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Zhao Z, Yang T, Xiang G, Zhang S, Cai Y, Zhong G, Pu J, Shen C, Zeng J, Chen C, Huang B. A novel small RNA PhaS contributes to polymyxin B-heteroresistance in carbapenem-resistant Klebsiella pneumoniae. Emerg Microbes Infect 2024; 13:2366354. [PMID: 38979571 PMCID: PMC11238654 DOI: 10.1080/22221751.2024.2366354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 06/05/2024] [Indexed: 07/10/2024]
Abstract
In recent years, polymyxin has been used as a last-resort therapy for carbapenem-resistant bacterial infections. The emergence of heteroresistance (HR) to polymyxin hampers the efficacy of polymyxin treatment by amplifying resistant subpopulation. However, the mechanisms behind polymyxin HR remain unclear. Small noncoding RNAs (sRNAs) play an important role in regulating drug resistance. The purpose of this study was to investigate the effects and mechanisms of sRNA on polymyxin B (PB)-HR in carbapenem-resistant Klebsiella pneumoniae. In this study, a novel sRNA PhaS was identified by transcriptome sequencing. PhaS expression was elevated in the PB heteroresistant subpopulation. Overexpression and deletion of PhaS were constructed in three carbapenem-resistant K. pneumoniae strains. Population analysis profiling, growth curve, and time-killing curve analysis showed that PhaS enhanced PB-HR. In addition, we verified that PhaS directly targeted phoP through the green fluorescent protein reporter system. PhaS promoted the expression of phoP, thereby encouraging the expression of downstream genes pmrD and arnT. This upregulation of arnT promoted the 4-amino-4-deoxyL-arabinosaccharide (L-Ara4N) modification of lipid A in PhaS overexpressing strains, thus enhancing PB-HR. Further, within the promoter region of PhaS, specific PhoP recognition sites were identified. ONPG assays and RT-qPCR analysis confirmed that PhaS expression was positively modulated by PhoP and thus up-regulated by PB stimulation. To sum up, a novel sRNA enhancing PB-HR was identified and a positive feedback regulatory pathway of sRNA-PhoP/Q was demonstrated in the study. This helps to provide a more comprehensive and clear understanding of the underlying mechanisms behind polymyxin HR in carbapenem-resistant K. pneumoniae.
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Affiliation(s)
- Zhiwei Zhao
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Tingting Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Guoxiu Xiang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Shebin Zhang
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Yimei Cai
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Guosheng Zhong
- Department of Clinical Laboratory, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Jieying Pu
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Cong Shen
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Jianming Zeng
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Cha Chen
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
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Bruna RE, Kendra CG, Pontes MH. An intracellular phosphorus-starvation signal activates the PhoB/PhoR two-component system in Salmonella enterica. mBio 2024; 15:e0164224. [PMID: 39152718 DOI: 10.1128/mbio.01642-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 07/01/2024] [Indexed: 08/19/2024] Open
Abstract
Bacteria acquire P primarily as inorganic orthophosphate (Pi, PO43-). Once internalized, Pi is rapidly assimilated into biomass during the synthesis of ATP. Because Pi is essential, but excessive ATP is toxic, the acquisition of environmental Pi is tightly regulated. In the bacterium Salmonella enterica (Salmonella), growth in Pi-limiting environments activates the membrane sensor histidine kinase PhoR, leading to the phosphorylation of its cognate transcriptional regulator PhoB and subsequent transcription of genes involved in adaptations to low Pi. Pi limitation promotes PhoR kinase activity by altering the conformation of a membrane signaling complex comprised of PhoR, the multicomponent Pi transporter system PstSACB and the regulatory protein PhoU. However, the identity of the Pi-starvation signal and how it controls PhoR activity remain unknown. Here, we identify conditions where the PhoB and PhoR signal transduction proteins can be maintained in an inactive state when Salmonella is grown in media lacking Pi. Our results demonstrate that PhoB/PhoR is activated by an intracellular P-insufficiency signal.IMPORTANCEIn enteric bacteria, the transcriptional response to phosphorus (P) starvation is controlled by a specialized signal transduction system comprised of a membrane-bound, multicomponent signal sensor, and a cytoplasmic transcriptional factor. Whereas this system has been primarily studied in the context of phosphate (Pi) starvation, it is currently unknown how this stress initiates signal transduction. In the current study, we establish that this signaling system is regulated by a cytoplasmic signal arising from insufficient P. We demonstrate that rather than responding to extracellular conditions, cells couple the activation of their P starvation response to the availability of cytoplasmic P. This regulatory logic may enable cells to prevent toxicity resulting from excessive Pi acquisition and hinder the onset of a P starvation response when their metabolic demands are being met through the consumption of P sources other than Pi.
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Affiliation(s)
- Roberto E Bruna
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, Camp Hill, Pennsylvania, USA
| | - Christopher G Kendra
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, Camp Hill, Pennsylvania, USA
| | - Mauricio H Pontes
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, Camp Hill, Pennsylvania, USA
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3
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Whittle EE, Orababa O, Osgerby A, Siasat P, Element SJ, Blair JMA, Overton TW. Efflux pumps mediate changes to fundamental bacterial physiology via membrane potential. mBio 2024:e0237024. [PMID: 39248573 DOI: 10.1128/mbio.02370-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Accepted: 08/15/2024] [Indexed: 09/10/2024] Open
Abstract
Efflux pumps are well known to be an important mechanism for removing noxious substances such as antibiotics from bacteria. Given that many antibiotics function by accumulating inside bacteria, efflux pumps contribute to resistance. Efflux pump inactivation is a potential strategy to combat antimicrobial resistance, as bacteria would not be able to pump out antibiotics. We recently discovered that the impact of loss of efflux function is only apparent in actively growing cells. We demonstrated that the global transcriptome of Salmonella Typhimurium is drastically altered during slower growth leading to stationary-phase cells having a remodeled, less permeable envelope that prevents antibiotics entering the cell. Here, we investigated the effects of deleting the major efflux pump of Salmonella Typhimurium, AcrB, on global gene transcription across growth. We revealed that an acrB knockout entered stationary phase later than the wild-type strain SL1344 and displayed increased and prolonged expression of genes responsible for anaerobic energy metabolism. We devised a model linking efflux and membrane potential, whereby deactivation of AcrB prevents influx of protons across the inner membrane and thereby hyperpolarization. Knockout or deactivation of AcrB was demonstrated to increase membrane potential. We propose that the global transcription regulator ArcBA senses changes to the redox state of the quinol pool (linked to the membrane potential of the bacterium) and coordinates the shift from exponential to stationary phase via the key master regulators RpoS, Rsd, and Rmf. Inactivation of efflux pumps therefore influences the fundamental physiology of Salmonella, with likely impacts on multiple phenotypes.IMPORTANCEWe demonstrate for the first time that deactivation of efflux pumps brings about changes to gross bacterial physiology and metabolism. Rather than simply being a response to noxious substances, efflux pumps appear to play a key role in maintenance of membrane potential and thereby energy metabolism. This discovery suggests that efflux pump inhibition or inactivation might have unforeseen positive consequences on antibiotic activity. Given that stationary-phase bacteria are more resistant to antibiotic uptake, late entry into stationary phase would prolong antibiotic accumulation by bacteria. Furthermore, membrane hyperpolarization could result in increased generation of reactive species proposed to be important for the activity of some antibiotics. Finally, changes in gross physiology could also explain the decreased virulence of efflux mutants.
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Affiliation(s)
- Emily E Whittle
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Oluwatosin Orababa
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Alexander Osgerby
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Pauline Siasat
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Sarah J Element
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Jessica M A Blair
- Department of Microbes, Infection and Microbiomes, Institute of Microbiology and Infection, College of Medical and Dental Sciences, Birmingham, United Kingdom
| | - Tim W Overton
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
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Seege M, Schöls E, Barquist L. s CIRCLE-An interactive visual exploration tool for single cell RNA-Seq data. NAR Genom Bioinform 2024; 6:lqae084. [PMID: 39022325 PMCID: PMC11252841 DOI: 10.1093/nargab/lqae084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 06/17/2024] [Accepted: 07/04/2024] [Indexed: 07/20/2024] Open
Abstract
sCIRCLE (single-Cell Interactive Real-time Computer visualization for Low-dimensional Exploration) is a tool for exploratory analysis of single cell RNA-seq (scRNA-seq) data sets, with a focus on bacterial scRNA-seq. The software takes an information design perspective to re-envision visually and interactively exploring low dimensional representations of scRNA-Seq data. Users can project cells in various 3D and 2D spaces and interactively query and paint cells using rich metadata sets reporting on cell cluster, gene function, and gene expression. As a standalone application it contains, among other features, options for dimensionality reduction, navigation and interaction with data in 3d and 2d space, gene filtering, fold change and metacell computation as well as various capabilities for visualization, data import and export.
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Affiliation(s)
- Maximilian Seege
- Technical University of Applied Sciences Würzburg-Schweinfurt, Faculty of Design, 97070 Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, 97080 Würzburg, Germany
| | - Erich Schöls
- Technical University of Applied Sciences Würzburg-Schweinfurt, Faculty of Design, 97070 Würzburg, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, 97080 Würzburg, Germany
- University of Würzburg, Faculty of Medicine, 97080 Würzburg, Germany
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
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5
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Thind MK, Miraglia E, Ling C, Khan MA, Glembocki A, Bourdon C, ChenMi Y, Palaniyar N, Glogauer M, Bandsma RHJ, Farooqui A. Mitochondrial perturbations in low-protein-diet-fed mice are associated with altered neutrophil development and effector functions. Cell Rep 2024; 43:114493. [PMID: 39028622 PMCID: PMC11372442 DOI: 10.1016/j.celrep.2024.114493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/16/2024] [Accepted: 06/26/2024] [Indexed: 07/21/2024] Open
Abstract
Severe malnutrition is associated with infections, namely lower respiratory tract infections (LRTIs), diarrhea, and sepsis, and underlies the high risk of morbidity and mortality in children under 5 years of age. Dysregulations in neutrophil responses in the acute phase of infection are speculated to underlie these severe adverse outcomes; however, very little is known about their biology in this context. Here, in a lipopolysaccharide-challenged low-protein diet (LPD) mouse model, as a model of malnutrition, we show that protein deficiency disrupts neutrophil mitochondrial dynamics and ATP generation to obstruct the neutrophil differentiation cascade. This promotes the accumulation of atypical immature neutrophils that are incapable of optimal antimicrobial response and, in turn, exacerbate systemic pathogen spread and the permeability of the alveolocapillary membrane with the resultant lung damage. Thus, this perturbed response may contribute to higher mortality risk in malnutrition. We also offer a nutritional therapeutic strategy, nicotinamide, to boost neutrophil-mediated immunity in LPD-fed mice.
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Affiliation(s)
- Mehakpreet K Thind
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; The Childhood Acute Illness & Nutrition Network (CHAIN), Nairobi, Kenya
| | - Emiliano Miraglia
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada; Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
| | - Catriona Ling
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Meraj A Khan
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Aida Glembocki
- Division of Pathology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Celine Bourdon
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; The Childhood Acute Illness & Nutrition Network (CHAIN), Nairobi, Kenya
| | - YueYing ChenMi
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Nades Palaniyar
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Michael Glogauer
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada; Department of Dental Oncology and Maxillofacial Prosthetics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Robert H J Bandsma
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; The Childhood Acute Illness & Nutrition Network (CHAIN), Nairobi, Kenya.
| | - Amber Farooqui
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; The Childhood Acute Illness & Nutrition Network (CHAIN), Nairobi, Kenya.
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Jerez SA, Mora AY, Millanao AR, Saavedra CP, Bucarey SA, Mora GC, Villagra NA, Hidalgo AA. Transcriptional regulator MarT negatively regulates MarT-regulated motility gene I, a new gene involved in invasion and virulence of Salmonella enterica. Front Microbiol 2024; 15:1430982. [PMID: 39211323 PMCID: PMC11358694 DOI: 10.3389/fmicb.2024.1430982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 06/24/2024] [Indexed: 09/04/2024] Open
Abstract
The speciation of Salmonella occurred by acquisition of genomic islands from other bacterial species and continued to diverge into subspecies and serovars with diferent range of host. S. enterica serovar Typhimurium (STM) is a generalist pathogen infecting hosts that include birds, mice, and humans, whilst S. enterica serovar Typhi (STY) is a restricted-host pathogen, infecting only humans. Despite their ranges of hosts, STM and STY possess 97-98% identity. Gain of genes by horizontal transference and loss of genes by mutations, are believed essential for differentiation of Salmonella. Salmonella pathogenicity island 3 (SPI-3) is an example combining these two processes. SPI-3 encodes misL and marT, among other genes. In STM, misL is required for gut colonization. Furthermore, protein MarT, positively regulates expression of misL by binding to misL-promoter. On the other hand, in SPI-3 of STY, marT and misL are pseudogenes. Interestingly, the gene t3766 (gene involved in resistance to H2O2) is present only in STY and is negatively regulated when marT STM is heterologously expressed in STY. Based on the view that MarT might regulate genes implicated in virulence, this work searched for new genes regulated by MarT. In silico searches for possible MarT target genes were performed, and 4 genes were selected for further analysis as they contained at least 2 copies of the consensus MarT-binding sequence in their promoters. Mutating marT in STM or heterologously expressing marT STM in STY confirmed that MarT negatively regulates ORF STY1408 or STM14_2003, its homologue in STM. STY1408 encodes for a putative protein with homology to methyl accepting chemotaxis proteins, which participate in chemotaxis and motility. Therefore, STY1408 was named mrmI (MarT-regulated motility gene I). Motility assays confirmed that the product of mrmI modulates motility. In addition, in vitro infection of cells with STM and STY mutants in mrmI reduces association with cells at 1, 3 and 24 h post-infection. Oral infection of mice showed that a mrmI null mutant was defective in producing systemic disease. Therefore, we conclude that MarT regulated mrmI, is involved in virulence of Salmonella. While pseudogenization of marT might modulate the fitness of narrow host range STY.
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Affiliation(s)
- Sebastián A. Jerez
- Programa de Doctorado en Biociencias Moleculares, Universidad Andres Bello, Santiago, Chile
| | - Aracely Y. Mora
- Advanced Center for Chronic Diseases, Facultad de Ciencias Químicas y Farmacéuticas & Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ana R. Millanao
- Instituto de Farmacia, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Claudia P. Saavedra
- Laboratorio de Microbiología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Sergio A. Bucarey
- Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Guido C. Mora
- Instituto de Investigación Interdisciplinar en Ciencias Biomédicas SEK (I3CBSEK), Facultad de Ciencias de la Salud, Universidad SEK, Santiago, Chile
| | - Nicolás A. Villagra
- Escuela de Tecnología Médica, Facultad de Salud, Universidad Santo Tomas, Santiago, Chile
| | - Alejandro A. Hidalgo
- Laboratorio de Microbiología Molecular, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
- Escuela de Química y Farmacia, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
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7
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Hong B, Qin T, Wang W, Li Y, Ma Y, Wang J. Phage tailspike protein coated gold nanoparticles combined with smartphone for rapid bacterial detection and photothermal sterilization. Talanta 2024; 276:126268. [PMID: 38762975 DOI: 10.1016/j.talanta.2024.126268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/09/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
The integration of recognition and therapeutic functions in multifunctional biosensors is of great importance in guaranteeing food security and reducing the occurrence of foodborne illness caused by foodborne pathogens. In this study, a biosensor utilizing a "sense-and-treat" approach was developed by integrating phage tailspike protein (TSP) with gold nanoparticles (AuNPs@TSP). The synthesized AuNPs@TSP showed strong binding affinity towards Salmonella typhimurium causing color changes and exhibited effective bactericidal activity when exposed to near-infrared (NIR) irradiation. This biosensor facilitated rapid colorimetric detection of S. typhimurium in 50 min, with a LOD (limit of detection) of 2.53 × 103 CFU/mL output on a smartphone APP after analyzing the red-green-blue (RGB) values from color rendering results. Furthermore, the biosensor displayed high selectivity, rapid response time, and broad applicability when tested with real samples. Moreover, the biosensor exhibited a remarkably efficient antibacterial efficacy of 100 % against S. typhimurium under 808 nm light irradiation for 6 min. This study provides a comprehensive investigation into the potential utilization of biosensors for rapid detection and eradication of foodborne pathogens in food industry.
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Affiliation(s)
- Bin Hong
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Ting Qin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Wenhai Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Yanmei Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Yi Ma
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, China.
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, China.
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8
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Kelly SD, Allas MJ, Goodridge LD, Lowary TL, Whitfield C. Structure, biosynthesis and regulation of the T1 antigen, a phase-variable surface polysaccharide conserved in many Salmonella serovars. Nat Commun 2024; 15:6504. [PMID: 39090110 PMCID: PMC11294581 DOI: 10.1038/s41467-024-50957-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 07/22/2024] [Indexed: 08/04/2024] Open
Abstract
The bacterial genus Salmonella includes diverse isolates with multiple variations in the structure of the main polysaccharide component (O antigen) of membrane lipopolysaccharides. In addition, some isolates produce a transient (T) antigen, such as the T1 polysaccharide identified in the 1960s in an isolate of Salmonella enterica Paratyphi B. The structure and biosynthesis of the T1 antigen have remained enigmatic. Here, we use biophysical, biochemical and genetic methods to show that the T1 antigen is a complex linear glycan containing tandem homopolymeric domains of galactofuranose and ribofuranose, linked to lipid A-core, like a typical O antigen. T1 is a phase-variable antigen, regulated by recombinational inversion of the promoter upstream of the T1 genetic locus through a mechanism not observed for other bacterial O antigens. The T1 locus is conserved across many Salmonella isolates, but is mutated or absent in most typhoidal serovars and in serovar Enteritidis.
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Affiliation(s)
- Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Mikel Jason Allas
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei, Taiwan
| | | | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada.
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
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9
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Yu XJ, Xie H, Li Y, Liu M, Hou R, Predeus AV, Perez Sepulveda BM, Hinton JCD, Holden DW, Thurston TLM. Modulation of Salmonella virulence by a novel SPI-2 injectisome effector that interacts with the dystrophin-associated protein complex. mBio 2024; 15:e0112824. [PMID: 38904384 PMCID: PMC11253597 DOI: 10.1128/mbio.01128-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/16/2024] [Indexed: 06/22/2024] Open
Abstract
The injectisome encoded by Salmonella pathogenicity island 2 (SPI-2) had been thought to translocate 28 effectors. Here, we used a proteomic approach to characterize the secretome of a clinical strain of invasive non-typhoidal Salmonella enterica serovar Enteritidis that had been mutated to cause hyper-secretion of the SPI-2 injectisome effectors. Along with many known effectors, we discovered the novel SseM protein. sseM is widely distributed among the five subspecies of Salmonella enterica, is found in many clinically relevant serovars, and is co-transcribed with pipB2, a SPI-2 effector gene. The translocation of SseM required a functional SPI-2 injectisome. Following expression in human cells, SseM interacted with five components of the dystrophin-associated protein complex (DAPC), namely, β-2-syntrophin, utrophin/dystrophin, α-catulin, α-dystrobrevin, and β-dystrobrevin. The interaction between SseM and β-2-syntrophin and α-dystrobrevin was verified in Salmonella Typhimurium-infected cells and relied on the postsynaptic density-95/discs large/zonula occludens-1 (PDZ) domain of β-2-syntrophin and a sequence corresponding to a PDZ-binding motif (PBM) in SseM. A ΔsseM mutant strain had a small competitive advantage over the wild-type strain in the S. Typhimurium/mouse model of systemic disease. This phenotype was complemented by a plasmid expressing wild-type SseM from S. Typhimurium or S. Enteritidis and was dependent on the PBM of SseM. Therefore, a PBM within a Salmonella effector mediates interactions with the DAPC and modulates the systemic growth of bacteria in mice. Furthermore, the ΔsseM mutant strain displayed enhanced replication in bone marrow-derived macrophages, demonstrating that SseM restrains intracellular bacterial growth to modulate Salmonella virulence. IMPORTANCE In Salmonella enterica, the injectisome machinery encoded by Salmonella pathogenicity island 2 (SPI-2) is conserved among the five subspecies and delivers proteins (effectors) into host cells, which are required for Salmonella virulence. The identification and functional characterization of SPI-2 injectisome effectors advance our understanding of the interplay between Salmonella and its host(s). Using an optimized method for preparing secreted proteins and a clinical isolate of the invasive non-typhoidal Salmonella enterica serovar Enteritidis strain D24359, we identified 22 known SPI-2 injectisome effectors and one new effector-SseM. SseM modulates bacterial growth during murine infection and has a sequence corresponding to a postsynaptic density-95/discs large/zonula occludens-1 (PDZ)-binding motif that is essential for interaction with the PDZ-containing host protein β-2-syntrophin and other components of the dystrophin-associated protein complex (DAPC). To our knowledge, SseM is unique among Salmonella effectors in containing a functional PDZ-binding motif and is the first bacterial protein to target the DAPC.
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Affiliation(s)
- Xiu-Jun Yu
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Haixia Xie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Yan Li
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Mei Liu
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Ruhong Hou
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Alexander V. Predeus
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Blanca M. Perez Sepulveda
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Jay C. D. Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - David W. Holden
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Teresa L. M. Thurston
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
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10
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Xu Y, Yu Z, Wu S, Song M, Cui L, Sun S, Wu J. Pathogenicity of Multidrug-Resistant Salmonella typhimurium Isolated from Ducks. Microorganisms 2024; 12:1359. [PMID: 39065127 PMCID: PMC11279134 DOI: 10.3390/microorganisms12071359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 06/28/2024] [Accepted: 06/29/2024] [Indexed: 07/28/2024] Open
Abstract
Salmonella typhimurium (S. typhimurium) is one of the most common Salmonella serotypes in epidemiological surveys of poultry farms in recent years. It causes growth retardation, mortality, and significant economic losses. The extensive use of antibiotics has led to the emergence of multi-drug resistance (MDR) in Salmonella, which has become a significant global problem and long-term challenge. In this study, we investigated the prevalence and features of S. typhimurium strains in duck embryos and cloacal swabs from large-scale duck farms in Shandong, China, including drug resistance and virulence genes and the pathogenicity of an S. typhimurium strain by animal experiment. The results demonstrated that a total of 8 S. typhimurium strains were isolated from 13,621 samples. The drug resistance results showed that three of the eight S. typhimurium strains were MDR with the dominant resistance profile of CTX-DX-CTR-TE-AMX-AMP-CAZ. In particular, the virulence genes invA, hilA, pefA, rck, and sefA showed high positive rates. Based on the analysis of the biological characteristics of bacterial biofilm formation and mobility, a strain of S. typhimurium with the strongest biofilm formation ability, designated 22SD07, was selected for animal infection experiments with broiler ducklings. The results of animal experiments demonstrated that infection with 22SD07 reduced body weight and bursa index but increased heart and liver indexes compared to the control group. Histological examination revealed desquamation of the intestinal villous epithelium, the presence of large aggregates of lymphocytes, and a decrease in goblet cells following infection. Furthermore, the expression of IL-10 was significantly increased in the liver at 3 dpi, while TNF-α was significantly increased in the spleen at 7 dpi. The above results indicate that S. typhimurium may pose a potential threat to human health through the food chain. This helps us to understand the frequency and characteristics of S. typhimurium in duck farms and emphasizes the urgent need to strengthen and implement effective continuous monitoring to control its infection and transmission.
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Affiliation(s)
- Yulin Xu
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan 250100, China;
- Key Laboratory of Livestock and Poultry Multi-Omics of MARA, Jinan 250100, China
| | - Zhitong Yu
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an 271000, China; (Z.Y.); (S.W.); (M.S.); (L.C.)
| | - Shaopeng Wu
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an 271000, China; (Z.Y.); (S.W.); (M.S.); (L.C.)
| | - Mengze Song
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an 271000, China; (Z.Y.); (S.W.); (M.S.); (L.C.)
| | - Lulu Cui
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an 271000, China; (Z.Y.); (S.W.); (M.S.); (L.C.)
| | - Shuhong Sun
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an 271000, China; (Z.Y.); (S.W.); (M.S.); (L.C.)
| | - Jiaqiang Wu
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan 250100, China;
- Key Laboratory of Livestock and Poultry Multi-Omics of MARA, Jinan 250100, China
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11
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Grabe GJ, Giorgio RT, Wieczór M, Gollan B, Sargen M, Orozco M, Hare SA, Helaine S. Molecular stripping underpins derepression of a toxin-antitoxin system. Nat Struct Mol Biol 2024; 31:1050-1060. [PMID: 38538913 DOI: 10.1038/s41594-024-01253-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024]
Abstract
Transcription factors control gene expression; among these, transcriptional repressors must liberate the promoter for derepression to occur. Toxin-antitoxin (TA) modules are bacterial elements that autoregulate their transcription by binding the promoter in a T:A ratio-dependent manner, known as conditional cooperativity. The molecular basis of how excess toxin triggers derepression has remained elusive, largely because monitoring the rearrangement of promoter-repressor complexes, which underpin derepression, is challenging. Here, we dissect the autoregulation of the Salmonella enterica tacAT3 module. Using a combination of assays targeting DNA binding and promoter activity, as well as structural characterization, we determine the essential TA and DNA elements required to control transcription, and we reconstitute a repression-to-derepression path. We demonstrate that excess toxin triggers molecular stripping of the repressor complex off the DNA through multiple allosteric changes causing DNA distortion and ultimately leading to derepression. Thus, our work provides important insight into the mechanisms underlying conditional cooperativity.
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Affiliation(s)
- Grzegorz J Grabe
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Rachel T Giorgio
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Miłosz Wieczór
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Bridget Gollan
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Molly Sargen
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Stephen A Hare
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
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12
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Traglia GM, Betancor L, Yim L, Iriarte A, Chabalgoity JA. Genotypic and phenotypic analysis of Salmonella enterica serovar Derby, looking for clues explaining the impairment of egg isolates to cause human disease. Front Microbiol 2024; 15:1357881. [PMID: 38903793 PMCID: PMC11186997 DOI: 10.3389/fmicb.2024.1357881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/23/2024] [Indexed: 06/22/2024] Open
Abstract
Salmonella enterica serovar Derby causes foodborne disease (FBD) outbreaks worldwide, mainly from contaminated pork but also from chickens. During a major epidemic of FBD in Uruguay due to S. enteritidis from poultry, we conducted a large survey of commercially available eggs, where we isolated many S. enteritidis strains but surprisingly also a much larger number (ratio 5:1) of S. Derby strains. No single case of S. Derby infection was detected in that period, suggesting that the S. Derby egg strains were impaired for human infection. We sequenced fourteen of these egg isolates, as well as fifteen isolates from pork or human infection that were isolated in Uruguay before and after that period, and all sequenced strains had the same sequence type (ST40). Phylogenomic analysis was conducted using more than 3,500 genomes from the same sequence type (ST), revealing that Uruguayan isolates clustered into four distantly related lineages. Population structure analysis (BAPS) suggested the division of the analyzed genomes into nine different BAPS1 groups, with Uruguayan strains clustering within four of them. All egg isolates clustered together as a monophyletic group and showed differences in gene content with the strains in the other clusters. Differences included variations in the composition of mobile genetic elements, such as plasmids, insertion sequences, transposons, and phages, between egg isolates and human/pork isolates. Egg isolates showed an acid susceptibility phenotype, reduced ability to reach the intestine after oral inoculation of mice, and reduced induction of SPI-2 ssaG gene, compared to human isolates from other monophyletic groups. Mice challenge experiments showed that mice infected intraperitoneally with human/pork isolates died between 1-7 days p.i., while all animals infected with the egg strain survived the challenge. Altogether, our results suggest that loss of genes functions, the insertion of phages and the absence of plasmids in egg isolates may explain why these S. Derby were not capable of producing human infection despite being at that time, the main serovar recovered from eggs countrywide.
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Affiliation(s)
| | | | | | - Andrés Iriarte
- Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - José Alejandro Chabalgoity
- Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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13
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Wang BX, Leshchiner D, Luo L, Tuncel M, Hokamp K, Hinton JCD, Monack DM. High-throughput fitness experiments reveal specific vulnerabilities of human-adapted Salmonella during stress and infection. Nat Genet 2024; 56:1288-1299. [PMID: 38831009 PMCID: PMC11176087 DOI: 10.1038/s41588-024-01779-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Salmonella enterica is comprised of genetically distinct 'serovars' that together provide an intriguing model for exploring the genetic basis of pathogen evolution. Although the genomes of numerous Salmonella isolates with broad variations in host range and human disease manifestations have been sequenced, the functional links between genetic and phenotypic differences among these serovars remain poorly understood. Here, we conduct high-throughput functional genomics on both generalist (Typhimurium) and human-restricted (Typhi and Paratyphi A) Salmonella at unprecedented scale in the study of this enteric pathogen. Using a comprehensive systems biology approach, we identify gene networks with serovar-specific fitness effects across 25 host-associated stresses encountered at key stages of human infection. By experimentally perturbing these networks, we characterize previously undescribed pseudogenes in human-adapted Salmonella. Overall, this work highlights specific vulnerabilities encoded within human-restricted Salmonella that are linked to the degradation of their genomes, shedding light into the evolution of this enteric pathogen.
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Affiliation(s)
- Benjamin X Wang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Lijuan Luo
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Miles Tuncel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Karsten Hokamp
- Department of Genetics, School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Jay C D Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Denise M Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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14
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Shore SFH, Leinberger FH, Fozo EM, Berghoff BA. Type I toxin-antitoxin systems in bacteria: from regulation to biological functions. EcoSal Plus 2024:eesp00252022. [PMID: 38767346 DOI: 10.1128/ecosalplus.esp-0025-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 04/11/2024] [Indexed: 05/22/2024]
Abstract
Toxin-antitoxin systems are ubiquitous in the prokaryotic world and widely distributed among chromosomes and mobile genetic elements. Several different toxin-antitoxin system types exist, but what they all have in common is that toxin activity is prevented by the cognate antitoxin. In type I toxin-antitoxin systems, toxin production is controlled by an RNA antitoxin and by structural features inherent to the toxin messenger RNA. Most type I toxins are small membrane proteins that display a variety of cellular effects. While originally discovered as modules that stabilize plasmids, chromosomal type I toxin-antitoxin systems may also stabilize prophages, or serve important functions upon certain stress conditions and contribute to population-wide survival strategies. Here, we will describe the intricate RNA-based regulation of type I toxin-antitoxin systems and discuss their potential biological functions.
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Affiliation(s)
- Selene F H Shore
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Florian H Leinberger
- Institute for Microbiology and Molecular Biology, Justus-Liebig University, Giessen, Germany
| | - Elizabeth M Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Bork A Berghoff
- Institute for Microbiology and Molecular Biology, Justus-Liebig University, Giessen, Germany
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15
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Fijalkowski I, Snauwaert V, Van Damme P. Proteins à la carte: riboproteogenomic exploration of bacterial N-terminal proteoform expression. mBio 2024; 15:e0033324. [PMID: 38511928 PMCID: PMC11005335 DOI: 10.1128/mbio.00333-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
In recent years, it has become evident that the true complexity of bacterial proteomes remains underestimated. Gene annotation tools are known to propagate biases and overlook certain classes of truly expressed proteins, particularly proteoforms-protein isoforms arising from a single gene. Recent (re-)annotation efforts heavily rely on ribosome profiling by providing a direct readout of translation to fully describe bacterial proteomes. In this study, we employ a robust riboproteogenomic pipeline to conduct a systematic census of expressed N-terminal proteoform pairs, representing two isoforms encoded by a single gene raised by annotated and alternative translation initiation, in Salmonella. Intriguingly, conditional-dependent changes in relative utilization of annotated and alternative translation initiation sites (TIS) were observed in several cases. This suggests that TIS selection is subject to regulatory control, adding yet another layer of complexity to our understanding of bacterial proteomes. IMPORTANCE With the emerging theme of genes within genes comprising the existence of alternative open reading frames (ORFs) generated by translation initiation at in-frame start codons, mechanisms that control the relative utilization of annotated and alternative TIS need to be unraveled and our molecular understanding of resulting proteoforms broadened. Utilizing complementary ribosome profiling strategies to map ORF boundaries, we uncovered dual-encoding ORFs generated by in-frame TIS usage in Salmonella. Besides demonstrating that alternative TIS usage may generate proteoforms with different characteristics, such as differential localization and specialized function, quantitative aspects of conditional retapamulin-assisted ribosome profiling (Ribo-RET) translation initiation maps offer unprecedented insights into the relative utilization of annotated and alternative TIS, enabling the exploration of gene regulatory mechanisms that control TIS usage and, consequently, the translation of N-terminal proteoform pairs.
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Affiliation(s)
- Igor Fijalkowski
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Valdes Snauwaert
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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16
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Delgadillo-Guevara M, Halte M, Erhardt M, Popp PF. Fluorescent tools for the standardized work in Gram-negative bacteria. J Biol Eng 2024; 18:25. [PMID: 38589953 PMCID: PMC11003136 DOI: 10.1186/s13036-024-00420-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 03/18/2024] [Indexed: 04/10/2024] Open
Abstract
Standardized and thoroughly characterized genetic tools are a prerequisite for studying cellular processes to ensure the reusability and consistency of experimental results. The discovery of fluorescent proteins (FPs) represents a milestone in the development of genetic reporters for monitoring transcription or protein localization in vivo. FPs have revolutionized our understanding of cellular dynamics by enabling the real-time visualization and tracking of biological processes. Despite these advancements, challenges remain in the appropriate use of FPs, specifically regarding their proper application, protein turnover dynamics, and the undesired disruption of cellular functions. Here, we systematically compared a comprehensive set of 15 FPs and assessed their performance in vivo by focusing on key parameters, such as signal over background ratios and protein stability rates, using the Gram-negative model organism Salmonella enterica as a representative host. We evaluated four protein degradation tags in both plasmid- and genome-based systems and our findings highlight the necessity of introducing degradation tags to analyze time-sensitive cellular processes. We demonstrate that the gain of dynamics mediated by the addition of degradation tags impacts the cell-to-cell heterogeneity of plasmid-based but not genome-based reporters. Finally, we probe the applicability of FPs for protein localization studies in living cells using standard and super-resolution fluorescence microscopy. In summary, our study underscores the importance of careful FP selection and paves the way for the development of improved genetic reporters to enhance the reproducibility and reliability of fluorescence-based research in Gram-negative bacteria and beyond.
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Affiliation(s)
- Mario Delgadillo-Guevara
- Institute of Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Manuel Halte
- Institute of Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Marc Erhardt
- Institute of Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
- Max Planck Unit for the Science of Pathogens, Berlin, 10117, Germany
| | - Philipp F Popp
- Institute of Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, 10115, Germany.
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17
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Jenniches L, Michaux C, Popella L, Reichardt S, Vogel J, Westermann AJ, Barquist L. Improved RNA stability estimation through Bayesian modeling reveals most Salmonella transcripts have subminute half-lives. Proc Natl Acad Sci U S A 2024; 121:e2308814121. [PMID: 38527194 PMCID: PMC10998600 DOI: 10.1073/pnas.2308814121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/16/2024] [Indexed: 03/27/2024] Open
Abstract
RNA decay is a crucial mechanism for regulating gene expression in response to environmental stresses. In bacteria, RNA-binding proteins (RBPs) are known to be involved in posttranscriptional regulation, but their global impact on RNA half-lives has not been extensively studied. To shed light on the role of the major RBPs ProQ and CspC/E in maintaining RNA stability, we performed RNA sequencing of Salmonella enterica over a time course following treatment with the transcription initiation inhibitor rifampicin (RIF-seq) in the presence and absence of these RBPs. We developed a hierarchical Bayesian model that corrects for confounding factors in rifampicin RNA stability assays and enables us to identify differentially decaying transcripts transcriptome-wide. Our analysis revealed that the median RNA half-life in Salmonella in early stationary phase is less than 1 min, a third of previous estimates. We found that over half of the 500 most long-lived transcripts are bound by at least one major RBP, suggesting a general role for RBPs in shaping the transcriptome. Integrating differential stability estimates with cross-linking and immunoprecipitation followed by RNA sequencing (CLIP-seq) revealed that approximately 30% of transcripts with ProQ binding sites and more than 40% with CspC/E binding sites in coding or 3' untranslated regions decay differentially in the absence of the respective RBP. Analysis of differentially destabilized transcripts identified a role for ProQ in the oxidative stress response. Our findings provide insights into posttranscriptional regulation by ProQ and CspC/E, and the importance of RBPs in regulating gene expression.
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Affiliation(s)
- Laura Jenniches
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
| | - Charlotte Michaux
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Linda Popella
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Sarah Reichardt
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
- Faculty of Medicine, University of Würzburg, Würzburg97080, Germany
| | - Alexander J. Westermann
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
- Faculty of Medicine, University of Würzburg, Würzburg97080, Germany
- Department of Biology, University of Toronto Mississauga, Mississauga, ONL5L 1C6Canada
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18
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Ryan D, Bornet E, Prezza G, Alampalli SV, Franco de Carvalho T, Felchle H, Ebbecke T, Hayward RJ, Deutschbauer AM, Barquist L, Westermann AJ. An expanded transcriptome atlas for Bacteroides thetaiotaomicron reveals a small RNA that modulates tetracycline sensitivity. Nat Microbiol 2024; 9:1130-1144. [PMID: 38528147 PMCID: PMC10994844 DOI: 10.1038/s41564-024-01642-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 02/07/2024] [Indexed: 03/27/2024]
Abstract
Plasticity in gene expression allows bacteria to adapt to diverse environments. This is particularly relevant in the dynamic niche of the human intestinal tract; however, transcriptional networks remain largely unknown for gut-resident bacteria. Here we apply differential RNA sequencing (RNA-seq) and conventional RNA-seq to the model gut bacterium Bacteroides thetaiotaomicron to map transcriptional units and profile their expression levels across 15 in vivo-relevant growth conditions. We infer stress- and carbon source-specific transcriptional regulons and expand the annotation of small RNAs (sRNAs). Integrating this expression atlas with published transposon mutant fitness data, we predict conditionally important sRNAs. These include MasB, which downregulates tetracycline tolerance. Using MS2 affinity purification and RNA-seq, we identify a putative MasB target and assess its role in the context of the MasB-associated phenotype. These data-publicly available through the Theta-Base web browser ( http://micromix.helmholtz-hiri.de/bacteroides/ )-constitute a valuable resource for the microbiome community.
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Affiliation(s)
- Daniel Ryan
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Elise Bornet
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Gianluca Prezza
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Shuba Varshini Alampalli
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Taís Franco de Carvalho
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Hannah Felchle
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
- Department of Radiation Oncology, Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany
| | - Titus Ebbecke
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Regan J Hayward
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
- Faculty of Medicine, University of Würzburg, Würzburg, Germany
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
- Department of Microbiology, Biocentre, University of Würzburg, Würzburg, Germany.
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19
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Kumwenda B, Canals R, Predeus AV, Zhu X, Kröger C, Pulford C, Wenner N, Lora LL, Li Y, Owen SV, Everett D, Hokamp K, Heyderman RS, Ashton PM, Gordon MA, Msefula CL, Hinton JCD. Salmonella enterica serovar Typhimurium ST313 sublineage 2.2 has emerged in Malawi with a characteristic gene expression signature and a fitness advantage. MICROLIFE 2024; 5:uqae005. [PMID: 38623411 PMCID: PMC11018118 DOI: 10.1093/femsml/uqae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 03/27/2024] [Indexed: 04/17/2024]
Abstract
Invasive non-typhoidal Salmonella (iNTS) disease is a serious bloodstream infection that targets immune-compromised individuals, and causes significant mortality in sub-Saharan Africa. Salmonella enterica serovar Typhimurium ST313 causes the majority of iNTS in Malawi. We performed an intensive comparative genomic analysis of 608 S. Typhimurium ST313 isolates dating between 1996 and 2018 from Blantyre, Malawi. We discovered that following the arrival of the well-characterized S. Typhimurium ST313 lineage 2 in 1999, two multidrug-resistant variants emerged in Malawi in 2006 and 2008, designated sublineages 2.2 and 2.3, respectively. The majority of S. Typhimurium isolates from human bloodstream infections in Malawi now belong to sublineages 2.2 or 2.3. To understand the emergence of the prevalent ST313 sublineage 2.2, we studied two representative strains, D23580 (lineage 2) and D37712 (sublineage 2.2). The chromosome of ST313 lineage 2 and sublineage 2.2 only differed by 29 SNPs/small indels and a 3 kb deletion of a Gifsy-2 prophage region including the sseI pseudogene. Lineage 2 and sublineage 2.2 had distinctive plasmid profiles. The transcriptome was investigated in 15 infection-relevant in vitro conditions and within macrophages. During growth in physiological conditions that do not usually trigger S. Typhimurium SPI2 gene expression, the SPI2 genes of D37712 were transcriptionally active. We identified down-regulation of flagellar genes in D37712 compared with D23580. Following phenotypic confirmation of transcriptomic differences, we discovered that sublineage 2.2 had increased fitness compared with lineage 2 during mixed growth in minimal media. We speculate that this competitive advantage is contributing to the emergence of sublineage 2.2 in Malawi.
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Affiliation(s)
- Benjamin Kumwenda
- School of Life Sciences and Allied Health Professions, Kamuzu University of Health Sciences Blantyre, Blantyre, 265, Malawi
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
| | - Rocío Canals
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Alexander V Predeus
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Xiaojun Zhu
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Carsten Kröger
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Caisey Pulford
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Nicolas Wenner
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Lizeth Lacharme Lora
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Yan Li
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Siân V Owen
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Dean Everett
- Department of Public Health and Epidemiology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, P.O. Box 127788, United Arab Emirates
| | - Karsten Hokamp
- Smurfit Institute of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Robert S Heyderman
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
- Research Department of Infection, Division of Infection & Immunity, University College London, London, WC1E 6BT, United Kingdom
| | | | - Melita A Gordon
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
| | - Chisomo L Msefula
- School of Life Sciences and Allied Health Professions, Kamuzu University of Health Sciences Blantyre, Blantyre, 265, Malawi
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
| | - Jay C D Hinton
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
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20
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Bergman S, Andresen L, Kjellin J, Martinez Burgo Y, Geiser P, Baars S, Söderbom F, Sellin ME, Holmqvist E. ProQ-dependent activation of Salmonella virulence genes mediated by post-transcriptional control of PhoP synthesis. mSphere 2024; 9:e0001824. [PMID: 38411119 PMCID: PMC10964419 DOI: 10.1128/msphere.00018-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 02/06/2024] [Indexed: 02/28/2024] Open
Abstract
Gastrointestinal disease caused by Salmonella enterica is associated with the pathogen's ability to replicate within epithelial cells and macrophages. Upon host cell entry, the bacteria express a type-three secretion system encoded within Salmonella pathogenicity island 2, through which host-manipulating effector proteins are secreted to establish a stable intracellular niche. Transcription of this intracellular virulence program is activated by the PhoPQ two-component system that senses the low pH and the reduced magnesium concentration of host cell vacuoles. In addition to transcriptional control, Salmonella commonly employ RNA-binding proteins (RBPs) and small regulatory RNAs (sRNAs) to regulate gene expression at the post-transcriptional level. ProQ is a globally acting RBP in Salmonella that promotes expression of the intracellular virulence program, but its RNA repertoire has previously been characterized only under standard laboratory growth conditions. Here, we provide a high-resolution ProQ interactome during conditions mimicking the environment of the Salmonella-containing vacuole (SCV), revealing hundreds of previously unknown ProQ binding sites in sRNAs and mRNA 3'UTRs. ProQ positively affected both the levels and the stability of many sRNA ligands, some of which were previously shown to associate with the well-studied and infection-relevant RBP Hfq. We further show that ProQ activates the expression of PhoP at the post-transcriptional level, which, in turn, leads to upregulation of the intracellular virulence program. IMPORTANCE Salmonella enterica is a major pathogen responsible for foodborne gastroenteritis, and a leading model organism for genetic and molecular studies of bacterial virulence mechanisms. One key trait of this pathogen is the ability to survive within infected host cells. During infection, the bacteria employ a type three secretion system that deliver effector proteins to target and manipulate host cell processes. The transcriptional regulation of this virulence program is well understood. By contrast, the factors and mechanisms operating at the post-transcriptional level to control virulence gene expression are less clear. In this study, we have charted the global RNA ligand repertoire of the RNA-binding protein ProQ during in vitro conditions mimicking the host cell environment. This identified hundreds of binding sites and revealed ProQ-dependent stabilization of intracellular-specific small RNAs. Importantly, we show that ProQ post-transcriptionally activates the expression of PhoP, a master transcriptional activator of intracellular virulence in Salmonella.
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Affiliation(s)
- Sofia Bergman
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Liis Andresen
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Jonas Kjellin
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Yolanda Martinez Burgo
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Petra Geiser
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sophie Baars
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Fredrik Söderbom
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Mikael E. Sellin
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Erik Holmqvist
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
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21
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Gerlach RG, Wittmann I, Heinrich L, Pinkenburg O, Meyer T, Elpers L, Schmidt C, Hensel M, Schnare M. Subversion of a family of antimicrobial proteins by Salmonella enterica. Front Cell Infect Microbiol 2024; 14:1375887. [PMID: 38505286 PMCID: PMC10948614 DOI: 10.3389/fcimb.2024.1375887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 02/19/2024] [Indexed: 03/21/2024] Open
Abstract
Salmonella enterica is a food-borne pathogen able to cause a wide spectrum of diseases ranging from mild gastroenteritis to systemic infections. During almost all stages of the infection process Salmonella is likely to be exposed to a wide variety of host-derived antimicrobial peptides (AMPs). AMPs are important components of the innate immune response which integrate within the bacterial membrane, thus forming pores which lead ultimately to bacterial killing. In contrast to other AMPs Bactericidal/Permeability-increasing Protein (BPI) displayed only weak bacteriostatic or bactericidal effects towards Salmonella enterica sv. Typhimurium (STM) cultures. Surprisingly, we found that sub-antimicrobial concentrations of BPI fold-containing (BPIF) superfamily members mediated adhesion of STM depending on pre-formed type 1 fimbriae. BPIF proteins directly bind to type 1 fimbriae through mannose-containing oligosaccharide modifications. Fimbriae decorated with BPIF proteins exhibit extended binding specificity, allowing for bacterial adhesion on a greater variety of abiotic and biotic surfaces likely promoting host colonization. Further, fimbriae significantly contributed to the resistance against BPI, probably through sequestration of the AMP before membrane interaction. In conclusion, functional subversion of innate immune proteins of the BPIF family through binding to fimbriae promotes Salmonella virulence by survival of host defense and promotion of host colonization.
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Affiliation(s)
- Roman G. Gerlach
- Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital of Erlangen and Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany
- Robert Koch Institute, Wernigerode, Germany
| | - Irene Wittmann
- Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital of Erlangen and Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany
| | | | - Olaf Pinkenburg
- Institute for Immunology, Philipps-University Marburg, Marburg, Germany
| | - Torben Meyer
- Institute for Immunology, Philipps-University Marburg, Marburg, Germany
| | - Laura Elpers
- Division of Microbiology and CellNanOs – Center of Cellular Nanoanalytics Osnabrück, School of Biology/Chemistry, University Osnabrück, Osnabrück, Germany
| | | | - Michael Hensel
- Division of Microbiology and CellNanOs – Center of Cellular Nanoanalytics Osnabrück, School of Biology/Chemistry, University Osnabrück, Osnabrück, Germany
| | - Markus Schnare
- Institute for Immunology, Philipps-University Marburg, Marburg, Germany
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22
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Schiavolin L, Deneubourg G, Steinmetz J, Smeesters PR, Botteaux A. Group A Streptococcus adaptation to diverse niches: lessons from transcriptomic studies. Crit Rev Microbiol 2024; 50:241-265. [PMID: 38140809 DOI: 10.1080/1040841x.2023.2294905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 12/10/2023] [Indexed: 12/24/2023]
Abstract
Group A Streptococcus (GAS) is a major human pathogen, causing diseases ranging from mild superficial infections of the skin and pharyngeal epithelium to severe systemic and invasive diseases. Moreover, post infection auto-immune sequelae arise by a yet not fully understood mechanism. The ability of GAS to cause a wide variety of infections is linked to the expression of a large set of virulence factors and their transcriptional regulation in response to various physiological environments. The use of transcriptomics, among others -omics technologies, in addition to traditional molecular methods, has led to a better understanding of GAS pathogenesis and host adaptation mechanisms. This review focusing on bacterial transcriptomic provides new insight into gene-expression patterns in vitro, ex vivo and in vivo with an emphasis on metabolic shifts, virulence genes expression and transcriptional regulators role.
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Affiliation(s)
- Lionel Schiavolin
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
| | - Geoffrey Deneubourg
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
| | - Jenny Steinmetz
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
| | - Pierre R Smeesters
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
- Department of Paediatrics, Brussels University Hospital, Academic Children Hospital Queen Fabiola, Université libre de Bruxelles, Brussels, Belgium
| | - Anne Botteaux
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
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23
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Olsen JE, Frees D, Kyvsgaard NC, Barco L. Lack of correlation between growth, stress, and virulence phenotypes in strains of Salmonella enterica serovar Enteritidis, S. Typhimurium DT104, S. 4,12, b:- and S. Liverpool. Lett Appl Microbiol 2024; 77:ovae015. [PMID: 38366187 DOI: 10.1093/lambio/ovae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/08/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024]
Abstract
Strains of Salmonella Enteritidis (SEnt, n = 10) and S. Typhimurium (STm, n = 11), representing clones with high impact on human health, and strains of S. 4,12: b:- (S412B n = 11) and S. Liverpool (SLiv, n = 4), representing clones with minor impact on human health were characterized for 16 growth, stress, and virulence phenotypes to investigate whether systematic differences exist in their performance in these phenotypes and whether there was correlation between performance in different phenotypes. The term serotype was not found to be predictive of a certain type of performance in any phenotype, and surprisingly, on average, strains of SEnt and STm were not significantly better in adhering to and invading cultured intestinal cells than the less pathogenic types. Forest analysis identified desiccation tolerance and the ability to grow at 42°C with high salt as the characters that separated serovars with low human health impact (S412B/SLiv) from serovars with high human health impact (SEnt/STm). The study showed that variation in phenotypes was high even within serovars and correlation between phenotypes was low, i.e. the way that a strain performed phenotypically in one of the tested conditions had a low predictive value for the performance of the strain in other conditions.
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Affiliation(s)
- John Elmerdahl Olsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C., Denmark
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C., Denmark
| | - Niels Christian Kyvsgaard
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C., Denmark
| | - Lisa Barco
- WOAH, National Reference Laboratory for Salmonella, Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Padova, Italy
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24
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Ning C, Li N, Wang L, Guo Y, Ji C, Li Z, Shang Y, Zhang X, Sun Y, Huang X, Leng Q, Cai X, Meng Q, Qiao J. STnc1280, a trans-coding sRNA is involved in virulence modulation via targeting gldA mRNA in Salmonella Typhimurium. J Med Microbiol 2024; 73. [PMID: 38353511 DOI: 10.1099/jmm.0.001804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Introduction. Salmonella Typhimurium (STM) is a food-borne Gram-negative bacterium, which can infect humans and a wide range of livestock and poultry, causing a variety of diseases such as septicaemia, enteritis and abortion.Hypothesis/Gap Statement. We will decipher the impacts of sRNA STnc1280 on STM virulence and provide a theoretical basis to reveal the regulatory role and molecular mechanism of STnc1280.Aim. The main objective of this study was to clarify whether sRNA STnc1280 exerts regulatory roles on STM pathogenicity.Methodology. The STnc1280 gene was amplified and its molecular characteristics were analysed in this study. Then, STnc1280 gene deletion strain (STM-ΔSTnc1280) and the complementary strain (ΔSTnc1280/STnc1280) were constructed by λ-Red homologous recombination method, respectively, to analyse of adhesion and invasive ability and pathogenicity of different strains. Subsequently, the potential target gene regulated by STnc1280 was predicted using target RNA2 software, followed by the verification of the interaction between STnc1280 and target mRNA using the dual plasmid reporter system (DPRS). Furthermore, the mRNA and protein level of target gene was determined using qRT-PCR and Western blot, respectively.Results. The results revealed that the cell adhesion and invasive ability and pathogenicity of STM-ΔSTnc1280 were significantly reduced compared to STM-SL1344 strain, indicating that the deficiency of STnc1280 gene significantly influenced STM pathogenicity. The DPRS results showed that STnc1280 can interact with the mRNA of target gene gldA, thus suppressing the expression of lacZ gene. Furthermore, the level of gldA mRNA was not influenced in STM-ΔSTnc1280, but the expression of GldA protein decreased significantly.Conclusion. Combining the bioinformatic analysis, these findings suggested that STnc1280 may bind to the SD sequence of gldA mRNA, hindering the binding of ribosomes to gldA mRNA, thereby inhibiting the expression of GldA protein to modulate the virulence of STM.
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Affiliation(s)
- Chengcheng Ning
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
- College of Animal Science and Technology, Xinjiang Agricultural Vocational and Technical College, Changji, Xinjiang, 831100, PR China
| | - Na Li
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Lixia Wang
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Yun Guo
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Chunhui Ji
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Zhiyuan Li
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Yunxia Shang
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Xingxing Zhang
- Institute of Animal Science and Veterinary Research, Xinjiang Academy of Agricultural and Reclamation Science, Shihezi, Xinjiang, 832000, PR China
| | - Yaoqiang Sun
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Xiaoxing Huang
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Qingwen Leng
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Xuepeng Cai
- State Key Lab of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, PR China
| | - Qingling Meng
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
| | - Jun Qiao
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR China
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25
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Lee SM, Le HT, Taizhanova A, Nong LK, Park JY, Lee EJ, Palsson BO, Kim D. Experimental promoter identification of a foodborne pathogen Salmonella enterica subsp. enterica serovar Typhimurium with near single base-pair resolution. Front Microbiol 2024; 14:1271121. [PMID: 38239730 PMCID: PMC10794520 DOI: 10.3389/fmicb.2023.1271121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 12/01/2023] [Indexed: 01/22/2024] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a common foodborne pathogen which is frequently used as the reference strain for Salmonella. Investigating the sigma factor network and protomers is crucial to understand the genomic and transcriptomic properties of the bacterium. Its promoters were identified using various methods such as dRNA-seq, ChIP-chip, or ChIP-Seq. However, validation using ChIP-exo, which exhibits higher-resolution performance compared to conventional ChIP, has not been conducted to date. In this study, using the representative strain S. Typhimurium LT2 (LT2), the ChIP-exo experiment was conducted to accurately determine the binding sites of catalytic RNA polymerase subunit RpoB and major sigma factors (RpoD, RpoN, RpoS, and RpoE) during exponential phase. Integrated with the results of RNA-Seq, promoters and sigmulons for the sigma factors and their association with RpoB have been discovered. Notably, the overlapping regions among binding sites of each alternative sigma factor were found. Furthermore, comparative analysis with Escherichia coli str. K-12 substr. MG1655 (MG1655) revealed conserved binding sites of RpoD and RpoN across different species. In the case of small RNAs (sRNAs), 50 sRNAs observed their expression during the exponential growth of LT2. Collectively, the integration of ChIP-exo and RNA-Seq enables genome-scale promoter mapping with high resolution and facilitates the characterization of binding events of alternative sigma factors, enabling a comprehensive understanding of the bacterial sigma factor network and condition-specific active promoters.
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Affiliation(s)
- Sang-Mok Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Hoa Thi Le
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Assiya Taizhanova
- Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, Republic of Korea
| | - Linh Khanh Nong
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Joon Young Park
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Eun-Jin Lee
- Department of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Bernhard O. Palsson
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
| | - Donghyuk Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
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26
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Koczerka M, Lantier I, Morillon M, Deperne J, Clamagirand CD, Virlogeux-Payant I, Grépinet O. From intestine to beyond: Salmonella entry factors display distinct transcription pattern upon infection in murine models. Open Biol 2024; 14:230312. [PMID: 38228171 DOI: 10.1098/rsob.230312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 12/14/2023] [Indexed: 01/18/2024] Open
Abstract
The infectious process of bacteria of the genus Salmonella requires the finely regulated use of various virulence factors. Among them, the type 3 secretion system-1 (T3SS-1) and the Rck and PagN invasins are involved in the internalization of the pathogen within eukaryotic cells, but their precise role in the host and in the pathogenic process is still poorly understood. In this study, we aimed to determine the kinetics of expression of these entry factors in a typhoid fever-like and a gastroenteritis model in mice by in vivo imaging using bioluminescent Salmonella Typhimurium reporter strains carrying chromosomal transcriptional fusions. Only pagN and T3SS-1 transcription has been clearly identified. Independently of the pathological model, the caecum was identified as the main transcription site of both pagN and the T3SS-1-encoding gene both at early and late stages of the infection. An intense transcription of pagN was also observed in deep organs in the typhoid fever-like model, while that of T3SS-1 remained quite sporadic in these organs, and mainly focused on the intestine all along the infection. This work will help to understand the respective role of these entry factors at the cellular level in the pathogenesis of Salmonella in vivo.
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Affiliation(s)
| | | | - Marie Morillon
- INRAE, Université de Tours, ISP, 37380, Nouzilly, France
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27
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Chubiz LM. The Mar, Sox, and Rob Systems. EcoSal Plus 2023; 11:eesp00102022. [PMID: 37220096 PMCID: PMC10729928 DOI: 10.1128/ecosalplus.esp-0010-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 03/03/2023] [Indexed: 01/28/2024]
Abstract
Environments inhabited by Enterobacteriaceae are diverse and often stressful. This is particularly true for Escherichia coli and Salmonella during host association in the gastrointestinal systems of animals. There, E. coli and Salmonella must survive exposure to various antimicrobial compounds produced or ingested by their host. A myriad of changes to cellular physiology and metabolism are required to achieve this feat. A central regulatory network responsible for sensing and responding to intracellular chemical stressors like antibiotics are the Mar, Sox, and Rob systems found throughout the Enterobacteriaceae. Each of these distinct regulatory networks controls expression of an overlapping set of downstream genes whose collective effects result in increased resistance to a wide array of antimicrobial compounds. This collection of genes is known as the mar-sox-rob regulon. This review will provide an overview of the mar-sox-rob regulon and molecular architecture of the Mar, Sox, and Rob systems.
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Affiliation(s)
- Lon M. Chubiz
- Department of Biology, University of Missouri–St. Louis, St. Louis, Missouri, USA
- Biochemistry and Biotechnology Program, University of Missouri–St. Louis, St. Louis, Missouri, USA
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28
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Bruna RE, Kendra CG, Pontes MH. Phosphorus starvation response and PhoB-independent utilization of organic phosphate sources by Salmonella enterica. Microbiol Spectr 2023; 11:e0226023. [PMID: 37787565 PMCID: PMC10715179 DOI: 10.1128/spectrum.02260-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/21/2023] [Indexed: 10/04/2023] Open
Abstract
IMPORTANCE Phosphorus (P) is the fifth most abundant element in living cells. This element is acquired mainly as inorganic phosphate (Pi, PO4 3-). In enteric bacteria, P starvation activates a two-component signal transduction system which is composed of the membrane sensor protein PhoR and its cognate transcription regulator PhoB. PhoB, in turn, promotes the transcription of genes that help maintain Pi homeostasis. Here, we characterize the P starvation response of the bacterium Salmonella enterica. We determine the PhoB-dependent and independent transcriptional changes promoted by P starvation and identify proteins enabling the utilization of a range of organic substrates as sole P sources. We show that transcription and activity of a subset of these proteins are independent of PhoB and Pi availability. These results establish that Salmonella enterica can maintain Pi homeostasis and repress PhoB/PhoR activation even when cells are grown in medium lacking Pi.
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Affiliation(s)
- Roberto E. Bruna
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Christopher G. Kendra
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Mauricio H. Pontes
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
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29
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Liu F, Chen Z, Zhang S, Wu K, Bei C, Wang C, Chao Y. In vivo RNA interactome profiling reveals 3'UTR-processed small RNA targeting a central regulatory hub. Nat Commun 2023; 14:8106. [PMID: 38062076 PMCID: PMC10703908 DOI: 10.1038/s41467-023-43632-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 11/15/2023] [Indexed: 12/18/2023] Open
Abstract
Small noncoding RNAs (sRNAs) are crucial regulators of gene expression in bacteria. Acting in concert with major RNA chaperones such as Hfq or ProQ, sRNAs base-pair with multiple target mRNAs and form large RNA-RNA interaction networks. To systematically investigate the RNA-RNA interactome in living cells, we have developed a streamlined in vivo approach iRIL-seq (intracellular RIL-seq). This generic approach is highly robust, illustrating the dynamic sRNA interactomes in Salmonella enterica across multiple stages of growth. We have identified the OmpD porin mRNA as a central regulatory hub that is targeted by a dozen sRNAs, including FadZ cleaved from the conserved 3'UTR of fadBA mRNA. Both ompD and FadZ are activated by CRP, constituting a type I incoherent feed-forward loop in the fatty acid metabolism pathway. Altogether, we have established an approach to profile RNA-RNA interactomes in live cells, highlighting the complexity of RNA regulatory hubs and RNA networks.
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Affiliation(s)
- Fang Liu
- Microbial RNA Systems Biology Unit, Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
- The Center for Microbes, Development and Health (CMDH), Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Ziying Chen
- Microbial RNA Systems Biology Unit, Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200033, China
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center & Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Shuo Zhang
- Microbial RNA Systems Biology Unit, Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
- The Center for Microbes, Development and Health (CMDH), Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kejing Wu
- Microbial RNA Systems Biology Unit, Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
- The Center for Microbes, Development and Health (CMDH), Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Cheng Bei
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200033, China
| | - Chuan Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200033, China.
| | - Yanjie Chao
- Microbial RNA Systems Biology Unit, Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China.
- The Center for Microbes, Development and Health (CMDH), Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Key Laboratory of RNA Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China.
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30
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Yang W, Feng Y, Yan J, Kang C, Yao T, Sun H, Cheng Z. Phosphate (Pi) Transporter PIT1 Induces Pi Starvation in Salmonella-Containing Vacuole in HeLa Cells. Int J Mol Sci 2023; 24:17216. [PMID: 38139044 PMCID: PMC10743064 DOI: 10.3390/ijms242417216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium), an important foodborne pathogen, causes diarrheal illness and gastrointestinal diseases. S. Typhimurium survives and replicates in phagocytic and non-phagocytic cells for acute or chronic infections. In these cells, S. Typhimurium resides within Salmonella-containing vacuoles (SCVs), in which the phosphate (Pi) concentration is low. S. Typhimurium senses low Pi and expresses virulence factors to modify host cells. However, the mechanism by which host cells reduce the Pi concentration in SCVs is not clear. In this study, we show that through the TLR4-MyD88-NF-κB signaling pathway, S. Typhimurium upregulates PIT1, which in turn transports Pi from SCVs into the cytosol and results in Pi starvation in SCVs. Immunofluorescence and western blotting analysis reveal that after the internalization of S. Typhimurium, PIT1 is located on SCV membranes. Silencing or overexpressing PIT1 inhibits or promotes Pi starvation, Salmonella pathogenicity island-2 (SPI-2) gene expression, and replication in SCVs. The S. Typhimurium ΔmsbB mutant or silenced TLR4-MyD88-NF-κB pathway suppresses the expression of the SPI-2 genes and promotes the fusion of SCVs with lysosomes. Our results illustrate that S. Typhimurium exploits the host innate immune responses as signals to promote intracellular replication, and they provide new insights for the development of broad-spectrum therapeutics to combat bacterial infections.
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Affiliation(s)
- Wen Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Yingxing Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jun Yan
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Chenbo Kang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Ting Yao
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Hongmin Sun
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Zhihui Cheng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
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31
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Moon JH, Roh DH, Kwack KH, Lee JH. Bacterial single-cell transcriptomics: Recent technical advances and future applications in dentistry. JAPANESE DENTAL SCIENCE REVIEW 2023; 59:253-262. [PMID: 37674900 PMCID: PMC10477369 DOI: 10.1016/j.jdsr.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 06/17/2023] [Accepted: 08/09/2023] [Indexed: 09/08/2023] Open
Abstract
Metagenomics and metatranscriptomics have enhanced our understanding of the oral microbiome and its impact on oral health. However, these approaches have inherent limitations in exploring individual cells and the heterogeneity within mixed microbial communities, which restricts our current understanding to bulk cells and species-level information. Fortunately, recent technical advances have enabled the application of single-cell RNA sequencing (scRNA-seq) for studying bacteria, shedding light on cell-to-cell diversity and interactions between host-bacterial cells at the single-cell level. Here, we address the technical barriers in capturing RNA from single bacterial cells and highlight pioneering studies from the past decade. We also discuss recent achievements in host-bacterial dual transcriptional profiling at the single-cell level. Bacterial scRNA-seq provides advantages in various research fields, including the investigation of phenotypic heterogeneity within genetically identical bacteria, identification of rare cell types, detection of antibiotic-resistant or persistent cells, analysis of individual gene expression patterns and metabolic activities, and characterization of specific microbe-host interactions. Integrating single-cell techniques with bulk approaches is essential to gain a comprehensive understanding of oral diseases and develop targeted and personalized treatment in dentistry. The reviewed pioneering studies are expected to inspire future research on the oral microbiome at the single-cell level.
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Affiliation(s)
- Ji-Hoi Moon
- Department of Oral Microbiology, College of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Dae-Hyun Roh
- Department of Oral Physiology, College of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Kyu Hwan Kwack
- Department of Oral Microbiology, College of Dentistry, Kyung Hee University, Seoul, Republic of Korea
| | - Jae-Hyung Lee
- Department of Oral Microbiology, College of Dentistry, Kyung Hee University, Seoul, Republic of Korea
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32
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Ramezanifard R, Golubeva YA, Palmer AD, Slauch JM. TamAB is regulated by PhoPQ and functions in outer membrane homeostasis during Salmonella pathogenesis. J Bacteriol 2023; 205:e0018323. [PMID: 37728604 PMCID: PMC10601761 DOI: 10.1128/jb.00183-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/12/2023] [Indexed: 09/21/2023] Open
Abstract
Salmonella survive and replicate in macrophages, which normally kill bacteria by exposing them to a variety of harsh conditions and antimicrobial effectors, many of which target the bacterial cell envelope. The PhoPQ two-component system responds to the phagosome environment and induces factors that protect the outer membrane, allowing adaptation and growth in the macrophage. We show that PhoPQ induces the transcription of the tamAB operon both in vitro and in macrophages. The TamA protein is structurally similar to BamA, an essential protein in the Bam complex that assembles β-barrel proteins in the outer membrane, while TamB is an AsmA-family protein implicated in lipid transport between the inner and outer membranes. We show that the Bam machinery is stressed in vitro under low Mg2+, low pH conditions that mimic the phagosome. Not surprisingly, mutations affecting Bam function confer significant virulence defects. Although loss of TamAB alone confers no virulence defect, a tamAB deletion confers a synthetic phenotype in bam mutant backgrounds in animals and macrophages, and in vitro upon treatment with vancomycin or sodium dodecyl sulfate. Mutations affecting YhdP, which functions in partial redundancy with TamB, also confer synthetic phenotypes with bam mutations in the animal, but this interaction is not evident in vitro. Thus, in the harsh phagocytic environment of the macrophage, the outer membrane Bam machinery is compromised, and the TamAB system, and perhaps other PhoPQ-regulated factors, is induced to compensate. It is most likely that TamAB and other systems assist the Bam complex indirectly by affecting outer membrane properties. IMPORTANCE The TamAB system has been implicated in both outer membrane protein localization and phospholipid transport between the inner and outer membranes. We show that the β-barrel protein assembly complex, Bam, is stressed under conditions thought to mimic the macrophage phagosome. TamAB expression is controlled by the PhoPQ two-component system and induced in macrophages. This system somehow compensates for the Bam complex as evidenced by the fact that mutations affecting the two systems confer synthetic phenotypes in animals, macrophages, and in vitro in the presence of vancomycin or SDS. This study has implications concerning the role of TamAB in outer membrane homeostasis. It also contributes to our understanding of the systems necessary for Salmonella to adapt and reproduce within the macrophage phagosome.
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Affiliation(s)
- Rouhallah Ramezanifard
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - Yekaterina A. Golubeva
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - Alexander D. Palmer
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - James M. Slauch
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
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33
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Zhu W, Xi L, Qiao J, Du D, Wang Y, Morigen. Involvement of OxyR and Dps in the repression of replication initiation by DsrA small RNA in Escherichia coli. Gene 2023; 882:147659. [PMID: 37482259 DOI: 10.1016/j.gene.2023.147659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 07/25/2023]
Abstract
Regulation of the cell cycle process is an effective measure to ensure the stability and fidelity of genetic material during the reproduction of bacteria under different stresses. The small RNA DsrA helps bacteria adapt to environments by binding to multiple targets, but its association with the cell cycle remains unclear. Detection by flow cytometry, we first found that the knockout of dsrA promoted replication initiation, and corresponding overexpression of DsrA inhibited replication initiation in Escherichia coli. The absence of the chaperone protein Hfq, the DNA replication negative regulator protein Dps, or the transcription factor OxyR, was found to cause DsrA to no longer inhibit replication initiation. Excess DsrA promotes expression of the oxyR and dps gene, whereas β-galactosidase activity assay showed that deleting oxyR limited the enhancement of dps promoter transcriptional activity by DsrA. OxyR is a known positive regulator of Dps. Our data suggests that the effect of DsrA on replication initiation requires Hfq and that the upregulation of Dps expression by OxyR in response to DsrA levels may be a potential regulatory pathway for the negative regulation of DNA replication initiation.
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Affiliation(s)
- Weiwei Zhu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Lingjun Xi
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Jiaxin Qiao
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Dongdong Du
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Yao Wang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Morigen
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China.
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Bharathan G, Mundra S, Darwich DM, Saeed MM, Al Hafri ASA, Alsalmi MMSM, Maqsood S, Mudgil P, Fanning S, Srikumar S. Regulation of iron metabolism is critical for the survival of Salmonella Typhimurium in pasteurized milk. Food Microbiol 2023; 115:104326. [PMID: 37567619 DOI: 10.1016/j.fm.2023.104326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 08/13/2023]
Abstract
Salmonella is known to survive in raw/pasteurized milk and cause foodborne outbreaks. Lactoferrin, present in milk from all animal sources, is an iron-binding glycoprotein that limits the availability of iron to pathogenic bacteria. Despite the presence of lactoferrins, Salmonella can grow in milk obtained from different animal sources. However, the mechanism by which Salmonella overcomes iron scarcity induced by lactoferrin in milk is not evaluated yet. Salmonella employs the DNA binding transcriptional regulator Fur (ferric update regulator) to mediate iron uptake during survival in iron deplete conditions. To understand the importance of Fur in Salmonella milk growth, we profiled the growth of Salmonella Typhimurium Δfur (ST4/74Δfur) in both bovine and camel milk. ST4/74Δfur was highly inhibited in milk compared to wild-type ST4/74, confirming the importance of Fur mediated regulation of iron metabolism in Salmonella milk growth. We further studied the biology of ST4/74Δfur to understand the importance of iron metabolism in Salmonella milk survival. Using increasing concentrations of FeCl3, and the antibiotic streptonigrin we show that iron accumulates in the cytoplasm of ST4/74Δfur. We hypothesized that the accumulated iron could activate oxidative stress via Fenton's reaction leading to growth inhibition. However, the inhibition of ST4/74Δfur in milk was not due to Fenton's reaction, but due to the 'iron scarce' conditions of milk and microaerophilic incubation conditions which made the presence of the fur gene indispensable for Salmonella milk growth. Subsequently, survival studies of 14 other transcriptional mutants of ST4/74 in milk confirmed that RpoE-mediated response to extracytoplasmic stress is also important for the survival of Salmonella in milk. Though we have data only for fur and rpoE, many other Salmonella transcriptional factors could play important roles in the growth of Salmonella in milk, a theme for future research on Salmonella milk biology. Nevertheless, our data provide early insights into the biology of milk-associated Salmonella.
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Affiliation(s)
- Greeshma Bharathan
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Sunil Mundra
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, 15551, United Arab Emirates; Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, Al Ain, 15551, United Arab Emirates
| | - Dania Mustafa Darwich
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Maitha Mohammad Saeed
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Ahad Saeed Ali Al Hafri
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | | | - Sajid Maqsood
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Priti Mudgil
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Séamus Fanning
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin, D04 N2E5, Ireland
| | - Shabarinath Srikumar
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates.
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35
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Smith C, Smith E, Chiu C, Hinton J, Perez Sepulveda B, Gordon M, Choy RK, Hill PW, Meiring JE, Darton TC, Carey ME, Cooke G, Gibani MM. The Challenge Non-Typhoidal Salmonella (CHANTS) Consortium: Development of a non-typhoidal Salmonella controlled human infection model: Report from a consultation group workshop, 05 July 2022, London, UK. Wellcome Open Res 2023; 8:111. [PMID: 37808389 PMCID: PMC10558987 DOI: 10.12688/wellcomeopenres.19012.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2023] [Indexed: 10/10/2023] Open
Abstract
Invasive non-typhoidal Salmonella disease (iNTS) is a major cause of morbidity and mortality globally, particularly as a cause of bloodstream infection in children and immunocompromised adults in sub-Saharan Africa. Vaccines to prevent non-typhoidal Salmonella (NTS) would represent a valuable public health tool in this setting to avert cases and prevent expansion of antimicrobial resistance. Several NTS and combination typhoidal-NTS vaccine candidates are in early-stage development, although the pathway to licensure is unclear due to challenges in conducting large phase III field trials. Controlled human infection models (CHIM) present an opportunity to accelerate vaccine development for a range of enteric pathogens. Several recent typhoidal Salmonella CHIMs have been conducted safely and have played pivotal roles in progressing vaccine candidates to pre-qualification and licensure. The Challenge Non-Typhoidal Salmonella (CHANTS) consortium has been formed with funding from the Wellcome Trust, to deliver the first NTS CHIM, which can act as a platform for future vaccine evaluation. This paper reports the conclusions of a consultation group workshop convened with key stakeholders. The aims of this meeting were to: (1) define the rationale for an NTS CHIM (2) map the NTS vaccine pipeline (3) refine study design and (4) establish potential future use cases.
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Affiliation(s)
- Christopher Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Emma Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Christopher Chiu
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Jay Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Blanca Perez Sepulveda
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Melita Gordon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Peter W.S. Hill
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - James E. Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Megan E. Carey
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Graham Cooke
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Malick M. Gibani
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - CHANTS Consortium
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- PATH, Seattle, Washington, 98121, USA
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
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36
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Smith C, Smith E, Chiu C, Hinton J, Perez Sepulveda B, Gordon M, Choy RK, Hill PW, Meiring JE, Darton TC, Carey ME, Cooke G, Gibani MM. The Challenge Non-Typhoidal Salmonella (CHANTS) Consortium: Development of a non-typhoidal Salmonella controlled human infection model: Report from a consultation group workshop, 05 July 2022, London, UK. Wellcome Open Res 2023; 8:111. [PMID: 37808389 PMCID: PMC10558987 DOI: 10.12688/wellcomeopenres.19012.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2023] [Indexed: 04/21/2024] Open
Abstract
Invasive non-typhoidal Salmonella disease (iNTS) is a major cause of morbidity and mortality globally, particularly as a cause of bloodstream infection in children and immunocompromised adults in sub-Saharan Africa. Vaccines to prevent non-typhoidal Salmonella (NTS) would represent a valuable public health tool in this setting to avert cases and prevent expansion of antimicrobial resistance. Several NTS and combination typhoidal-NTS vaccine candidates are in early-stage development, although the pathway to licensure is unclear due to challenges in conducting large phase III field trials. Controlled human infection models (CHIM) present an opportunity to accelerate vaccine development for a range of enteric pathogens. Several recent typhoidal Salmonella CHIMs have been conducted safely and have played pivotal roles in progressing vaccine candidates to pre-qualification and licensure. The Challenge Non-Typhoidal Salmonella (CHANTS) consortium has been formed with funding from the Wellcome Trust, to deliver the first NTS CHIM, which can act as a platform for future vaccine evaluation. This paper reports the conclusions of a consultation group workshop convened with key stakeholders. The aims of this meeting were to: (1) define the rationale for an NTS CHIM (2) map the NTS vaccine pipeline (3) refine study design and (4) establish potential future use cases.
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Affiliation(s)
- Christopher Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Emma Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Christopher Chiu
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Jay Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Blanca Perez Sepulveda
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Melita Gordon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Peter W.S. Hill
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - James E. Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Megan E. Carey
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Graham Cooke
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Malick M. Gibani
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - CHANTS Consortium
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- PATH, Seattle, Washington, 98121, USA
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
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37
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Fels U, Willems P, De Meyer M, Gevaert K, Van Damme P. Shift in vacuolar to cytosolic regime of infecting Salmonella from a dual proteome perspective. PLoS Pathog 2023; 19:e1011183. [PMID: 37535689 PMCID: PMC10426988 DOI: 10.1371/journal.ppat.1011183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/15/2023] [Accepted: 06/19/2023] [Indexed: 08/05/2023] Open
Abstract
By applying dual proteome profiling to Salmonella enterica serovar Typhimurium (S. Typhimurium) encounters with its epithelial host (here, S. Typhimurium infected human HeLa cells), a detailed interdependent and holistic proteomic perspective on host-pathogen interactions over the time course of infection was obtained. Data-independent acquisition (DIA)-based proteomics was found to outperform data-dependent acquisition (DDA) workflows, especially in identifying the downregulated bacterial proteome response during infection progression by permitting quantification of low abundant bacterial proteins at early times of infection when bacterial infection load is low. S. Typhimurium invasion and replication specific proteomic signatures in epithelial cells revealed interdependent host/pathogen specific responses besides pointing to putative novel infection markers and signalling responses, including regulated host proteins associated with Salmonella-modified membranes.
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Affiliation(s)
- Ursula Fels
- iRIP unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
| | - Patrick Willems
- iRIP unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Margaux De Meyer
- iRIP unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Petra Van Damme
- iRIP unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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38
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Jiao C, Reckstadt C, König F, Homberger C, Yu J, Vogel J, Westermann AJ, Sharma CM, Beisel CL. RNA recording in single bacterial cells using reprogrammed tracrRNAs. Nat Biotechnol 2023; 41:1107-1116. [PMID: 36604543 PMCID: PMC7614944 DOI: 10.1038/s41587-022-01604-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 11/07/2022] [Indexed: 01/07/2023]
Abstract
Capturing an individual cell's transcriptional history is a challenge exacerbated by the functional heterogeneity of cellular communities. Here, we leverage reprogrammed tracrRNAs (Rptrs) to record selected cellular transcripts as stored DNA edits in single living bacterial cells. Rptrs are designed to base pair with sensed transcripts, converting them into guide RNAs. The guide RNAs then direct a Cas9 base editor to target an introduced DNA target. The extent of base editing can then be read in the future by sequencing. We use this approach, called TIGER (transcribed RNAs inferred by genetically encoded records), to record heterologous and endogenous transcripts in individual bacterial cells. TIGER can quantify relative expression, distinguish single-nucleotide differences, record multiple transcripts simultaneously and read out single-cell phenomena. We further apply TIGER to record metabolic bet hedging and antibiotic resistance mobilization in Escherichia coli as well as host cell invasion by Salmonella. Through RNA recording, TIGER connects current cellular states with past transcriptional states to decipher complex cellular responses in single cells.
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Affiliation(s)
- Chunlei Jiao
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Claas Reckstadt
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Fabian König
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Christina Homberger
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Jiaqi Yu
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
- Medical Faculty, University of Würzburg, Würzburg, Germany
| | - Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Cynthia M Sharma
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany.
- Medical Faculty, University of Würzburg, Würzburg, Germany.
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Bhatia RP, Kirit HA, Lewis CM, Sankaranarayanan K, Bollback JP. Evolutionary barriers to horizontal gene transfer in macrophage-associated Salmonella. Evol Lett 2023; 7:227-239. [PMID: 37475746 PMCID: PMC10355182 DOI: 10.1093/evlett/qrad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 04/06/2023] [Accepted: 04/20/2023] [Indexed: 07/22/2023] Open
Abstract
Horizontal gene transfer (HGT) is a powerful evolutionary force facilitating bacterial adaptation and emergence of novel phenotypes. Several factors, including environmental ones, are predicted to restrict HGT, but we lack systematic and experimental data supporting these predictions. Here, we address this gap by measuring the relative fitness of 44 genes horizontally transferred from Escherichia coli to Salmonella enterica in infection-relevant environments. We estimated the distribution of fitness effects in each environment and identified that dosage-dependent effects across different environments are a significant barrier to HGT. The majority of genes were found to be deleterious. We also found longer genes had stronger negative fitness consequences than shorter ones, showing that gene length was negatively associated with HGT. Furthermore, fitness effects of transferred genes were found to be environmentally dependent. In summary, a substantial fraction of transferred genes had a significant fitness cost on the recipient, with both gene characteristics and the environment acting as evolutionary barriers to HGT.
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Affiliation(s)
- Rama P Bhatia
- Institute of Infection, Veterinary, and Ecological Sciences, Department of Evolution, Ecology, and Behaviour, University of Liverpool, Liverpool, United Kingdom
| | - Hande Acar Kirit
- Institute of Infection, Veterinary, and Ecological Sciences, Department of Evolution, Ecology, and Behaviour, University of Liverpool, Liverpool, United Kingdom
- Laboratories of Molecular Anthropology and Microbiome Research (LMAMR), University of Oklahoma, Norman, OK, United States
| | - Cecil M Lewis
- Laboratories of Molecular Anthropology and Microbiome Research (LMAMR), University of Oklahoma, Norman, OK, United States
- Department of Anthropology, University of Oklahoma, Norman, OK, United States
| | - Krithivasan Sankaranarayanan
- Laboratories of Molecular Anthropology and Microbiome Research (LMAMR), University of Oklahoma, Norman, OK, United States
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Jonathan P Bollback
- Corresponding author: Institute of Infection, Veterinary, and Ecological Sciences, Department of Evolution, Ecology, and Behaviour, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom.
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40
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Singh M, Penmatsa A, Nandi D. Functional Characterization of Salmonella Typhimurium Encoded YciF, a Domain of Unknown Function (DUF892) Family Protein, and Its Role in Protection during Bile and Oxidative Stress. J Bacteriol 2023; 205:e0005923. [PMID: 37367303 PMCID: PMC10367587 DOI: 10.1128/jb.00059-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
YciF (STM14_2092) is a member of the domain of unknown function (DUF892) family. It is an uncharacterized protein involved in stress responses in Salmonella Typhimurium. In this study, we investigated the significance of YciF and its DUF892 domain during bile and oxidative stress responses of S. Typhimurium. Purified wild-type YciF forms higher order oligomers, binds to iron, and displays ferroxidase activity. Studies on the site-specific mutants revealed that the ferroxidase activity of YciF is dependent on the two metal binding sites present within the DUF892 domain. Transcriptional analysis displayed that the ΔcspE strain, which has compromised expression of YciF, encounters iron toxicity due to dysregulation of iron homeostasis in the presence of bile. Utilizing this observation, we demonstrate that the bile mediated iron toxicity in ΔcspE causes lethality, primarily through the generation of reactive oxygen species (ROS). Expression of wild-type YciF, but not the three mutants of the DUF892 domain, in ΔcspE alleviate ROS in the presence of bile. Our results establish the role of YciF as a ferroxidase that can sequester excess iron in the cellular milieu to counter ROS-associated cell death. This is the first report of biochemical and functional characterization of a member of the DUF892 family. IMPORTANCE The DUF892 domain has a wide taxonomic distribution encompassing several bacterial pathogens. This domain belongs to the ferritin-like superfamily; however, it has not been biochemically and functionally characterized. This is the first report of characterization of a member of this family. In this study, we demonstrate that S. Typhimurium YciF is an iron binding protein with ferroxidase activity, which is dependent on the metal binding sites present within the DUF892 domain. YciF combats iron toxicity and oxidative damage caused due to exposure to bile. The functional characterization of YciF delineates the significance of the DUF892 domain in bacteria. In addition, our studies on S. Typhimurium bile stress response divulged the importance of comprehensive iron homeostasis and ROS in bacteria.
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Affiliation(s)
- Madhulika Singh
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Aravind Penmatsa
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Dipankar Nandi
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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41
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Hu D, Laczkovich I, Federle MJ, Morrison DA. Identification and Characterization of Negative Regulators of Rgg1518 Quorum Sensing in Streptococcus pneumoniae. J Bacteriol 2023; 205:e0008723. [PMID: 37341600 PMCID: PMC10367586 DOI: 10.1128/jb.00087-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 06/02/2023] [Indexed: 06/22/2023] Open
Abstract
Streptococcus pneumoniae is an agent of otitis media, septicemia, and meningitis and remains the leading cause of community-acquired pneumonia regardless of vaccine use. Of the various strategies that S. pneumoniae takes to enhance its potential to colonize the human host, quorum sensing (QS) is an intercellular communication process that provides coordination of gene expression at a community level. Numerous putative QS systems are identifiable in the S. pneumoniae genome, but their gene-regulatory activities and contributions to fitness have yet to be fully evaluated. To contribute to assessing regulatory activities of rgg paralogs present in the D39 genome, we conducted transcriptomic analysis of mutants of six QS regulators. Our results find evidence that at least four QS regulators impact the expression of a polycistronic operon (encompassing genes spd_1517 to spd_1513) that is directly controlled by the Rgg/SHP1518 QS system. As an approach to unravel the convergent regulation placed on the spd_1513-1517 operon, we deployed transposon mutagenesis screening in search of upstream regulators of the Rgg/SHP1518 QS system. The screen identified two types of insertion mutants that result in increased activity of Rgg1518-dependent transcription, one type being where the transposon inserted into pepO, an annotated endopeptidase, and the other type being insertions in spxB, a pyruvate oxidase. We demonstrate that pneumococcal PepO degrades SHP1518 to prevent activation of Rgg/SHP1518 QS. Moreover, the glutamic acid residue in the conserved "HExxH" domain is indispensable for the catalytic function of PepO. Finally, we confirmed the metalloendopeptidase property of PepO, which requires zinc ions, but not other ions, to facilitate peptidyl hydrolysis. IMPORTANCE Streptococcus pneumoniae uses quorum sensing to communicate and regulate virulence. In our study, we focused on one Rgg quorum sensing system (Rgg/SHP1518) and found that multiple other Rgg regulators also control it. We further identified two enzymes that inhibit Rgg/SHP1518 signaling and revealed and validated one enzyme's mechanisms for breaking down quorum sensing signaling molecules. Our findings shed light on the complex regulatory network of quorum sensing in Streptococcus pneumoniae.
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Affiliation(s)
- Duoyi Hu
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Irina Laczkovich
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Michael J. Federle
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
- Center for Biomolecular Science, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Donald A. Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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42
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Wang F, Wang Z, Tang J. The interactions of Candida albicans with gut bacteria: a new strategy to prevent and treat invasive intestinal candidiasis. Gut Pathog 2023; 15:30. [PMID: 37370138 DOI: 10.1186/s13099-023-00559-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND The gut microbiota plays an important role in human health, as it can affect host immunity and susceptibility to infectious diseases. Invasive intestinal candidiasis is strongly associated with gut microbiota homeostasis. However, the nature of the interaction between Candida albicans and gut bacteria remains unclear. OBJECTIVE This review aimed to determine the nature of interaction and the effects of gut bacteria on C. albicans so as to comprehend an approach to reducing intestinal invasive infection by C. albicans. METHODS This review examined 11 common gut bacteria's interactions with C. albicans, including Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus faecalis, Staphylococcus aureus, Salmonella spp., Helicobacter pylori, Lactobacillus spp., Bacteroides spp., Clostridium difficile, and Streptococcus spp. RESULTS Most of the studied bacteria demonstrated both synergistic and antagonistic effects with C. albicans, and just a few bacteria such as P. aeruginosa, Salmonella spp., and Lactobacillus spp. demonstrated only antagonism against C. albicans. CONCLUSIONS Based on the nature of interactions reported so far by the literature between gut bacteria and C. albicans, it is expected to provide new ideas for the prevention and treatment of invasive intestinal candidiasis.
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Affiliation(s)
- Fei Wang
- Department of Trauma-Emergency & Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University, 128 Ruili Road, Shanghai, 200240, China
| | - Zetian Wang
- Department of Trauma-Emergency & Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University, 128 Ruili Road, Shanghai, 200240, China.
| | - Jianguo Tang
- Department of Trauma-Emergency & Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University, 128 Ruili Road, Shanghai, 200240, China.
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43
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Münch JM, Sobol MS, Brors B, Kaster AK. Single-cell transcriptomics and data analyses for prokaryotes-Past, present and future concepts. ADVANCES IN APPLIED MICROBIOLOGY 2023; 123:1-39. [PMID: 37400172 DOI: 10.1016/bs.aambs.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Transcriptomics, or more specifically mRNA sequencing, is a powerful tool to study gene expression at the single-cell level (scRNA-seq) which enables new insights into a plethora of biological processes. While methods for single-cell RNA-seq in eukaryotes are well established, application to prokaryotes is still challenging. Reasons for that are rigid and diverse cell wall structures hampering lysis, the lack of polyadenylated transcripts impeding mRNA enrichment, and minute amounts of RNA requiring amplification steps before sequencing. Despite those obstacles, several promising scRNA-seq approaches for bacteria have been published recently, albeit difficulties in the experimental workflow and data processing and analysis remain. In particular, bias is often introduced by amplification which makes it difficult to distinguish between technical noise and biological variation. Future optimization of experimental procedures and data analysis algorithms are needed for the improvement of scRNA-seq but also to aid in the emergence of prokaryotic single-cell multi-omics. to help address 21st century challenges in the biotechnology and health sector.
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Affiliation(s)
- Julia M Münch
- Institute for Biological Interfaces 5, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany; Division of Applied Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Biosciences, Heidelberg University, Heidelberg, Germany; HIDSS4Health - Helmholtz Information and Data Science School for Health, Karlsruhe/Heidelberg, Germany
| | - Morgan S Sobol
- Institute for Biological Interfaces 5, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Benedikt Brors
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany; HIDSS4Health - Helmholtz Information and Data Science School for Health, Karlsruhe/Heidelberg, Germany
| | - Anne-Kristin Kaster
- Institute for Biological Interfaces 5, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany; HIDSS4Health - Helmholtz Information and Data Science School for Health, Karlsruhe/Heidelberg, Germany.
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44
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Jiang L, Li W, Hou X, Ma S, Wang X, Yan X, Yang B, Huang D, Liu B, Feng L. Nitric oxide is a host cue for Salmonella Typhimurium systemic infection in mice. Commun Biol 2023; 6:501. [PMID: 37161082 PMCID: PMC10169850 DOI: 10.1038/s42003-023-04876-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 04/26/2023] [Indexed: 05/11/2023] Open
Abstract
Nitric oxide (NO) is produced as an innate immune response against microbial infections. Salmonella Typhimurium (S. Typhimurium), the major causative pathogen of human gastroenteritis, induces more severe systemic disease in mice. However, host factors contributing to the difference in species-related virulence are unknown. Here, we report that host NO production promotes S. Typhimurium replication in mouse macrophages at the early infection stage by activating Salmonella pathogenicity island-2 (SPI-2). The NO signaling-induced SPI-2 activation is mediated by Fnr and PhoP/Q two-component system. NO significantly induced fnr transcription, while Fnr directly activated phoP/Q transcription. Mouse infection assays revealed a NO-dependent increase in bacterial burden in systemic organs during the initial days of infection, indicating an early contribution of host NO to virulence. This study reveals a host signaling-mediated virulence activation pathway in S. Typhimurium that contributes significantly to its systemic infection in mice, providing further insights into Salmonella pathogenesis and host-pathogen interaction.
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Affiliation(s)
- Lingyan Jiang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Wanwu Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xi Hou
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Shuai Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xinyue Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xiaolin Yan
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Bin Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Di Huang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Bin Liu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Lu Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China.
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Middlemiss AD, Warman EA, Forrest D, Haycocks JRJ, Grainger DC. An unexpected abundance of bidirectional promoters within Salmonella Typhimurium plasmids. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001339. [PMID: 37204130 PMCID: PMC10268837 DOI: 10.1099/mic.0.001339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/05/2023] [Indexed: 05/20/2023]
Abstract
Transcription of the DNA template, to generate an RNA message, is the first step in gene expression. The process initiates at DNA sequences called promoters. Conventionally, promoters have been considered to drive transcription in a specific direction. However, in recent work, we showed that many prokaryotic promoters can drive divergent transcription. This is a consequence of key DNA sequences for transcription initiation being inherently symmetrical. Here, we used global transcription start site mapping to determine the prevalence of such bidirectional promoters in Salmonella Typhimurium. Surprisingly, bidirectional promoters occur three times more frequently in plasmid components of the genome compared to chromosomal DNA. Implications for the evolution of promoter sequences are discussed.
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Affiliation(s)
| | - Emily A. Warman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - David Forrest
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - James R. J. Haycocks
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - David C. Grainger
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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46
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Bruna RE, Kendra CG, Pontes MH. An intracellular phosphorus-starvation signal activates the PhoB/PhoR two-component system in Salmonella enterica. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533958. [PMID: 36993483 PMCID: PMC10055408 DOI: 10.1101/2023.03.23.533958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Bacteria acquire P primarily as inorganic orthophosphate (Pi, PO43-). Once internalized, Pi is rapidly assimilated into biomass during the synthesis of ATP. Because Pi is essential, but excessive ATP is toxic, the acquisition of environmental Pi is tightly regulated. In the bacterium Salmonella enterica (Salmonella), growth in Pi-limiting environments activates the membrane sensor histidine kinase PhoR, leading to the phosphorylation of its cognate transcriptional regulator PhoB and subsequent transcription of genes involved in adaptations to low Pi. Pi limitation is thought to promote PhoR kinase activity by altering the conformation of a membrane signaling complex comprised by PhoR, the multicomponent Pi transporter system PstSACB and the regulatory protein PhoU. However, the identity of the low Pi signal and how it controls PhoR activity remain unknown. Here we characterize the PhoB-dependent and independent transcriptional changes elicited by Salmonella in response to P starvation, and identify PhoB-independent genes that are required for the utilization of several organic-P sources. We use this knowledge to identify the cellular compartment where the PhoR signaling complex senses the Pi-limiting signal. We demonstrate that the PhoB and PhoR signal transduction proteins can be maintained in an inactive state even when Salmonella is grown in media lacking Pi. Our results establish that PhoR activity is controlled by an intracellular signal resulting from P insufficiency.
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Affiliation(s)
- Roberto E. Bruna
- Department of Pathology and Laboratory Medicine, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
| | - Christopher G. Kendra
- Department of Pathology and Laboratory Medicine, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
| | - Mauricio H. Pontes
- Department of Pathology and Laboratory Medicine, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
- Department of Microbiology and Immunology, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
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47
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Lallement C, Goldring WPD, Jelsbak L. Global transcriptomic response of the AI-3 isomers 3,5-DPO and 3,6-DPO in Salmonella Typhimurium. Arch Microbiol 2023; 205:117. [PMID: 36929450 DOI: 10.1007/s00203-023-03450-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/14/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023]
Abstract
Bacterial intercellular signaling mediated by small molecules, also called autoinducers (AIs), enables synchronized behavior in response to environmental conditions, and in many bacterial pathogens, intercellular signaling controls virulence gene expression. However, in the intestinal pathogen Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium), although three signals, named AI-1, AI-2 and AI-3, have been described, their roles in virulence remain elusive. AI-3 is the 3,6- isomer of a previously described Vibrio cholerae signaling molecule; 3,5-dimethylpyrazin-2-ol (3,5-DPO). To elucidate the role of AI-3/DPO in S. Typhimurium, we have mapped the global transcriptomic responses to 3,5- and 3,6-DPO isomers in S. Typhimurium. Our studies showed that DPO affects expression of almost 8% of all genes. Specifically, expression of several genes involved in gut-colonization respond to DPO. Interestingly, most of the affected genes are similarly regulated by 3,5-DPO and 3,6-DPO, respectively, indicating that the two isomers have overlapping roles in S. Typhimurium.
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Affiliation(s)
- Claire Lallement
- Department of Sciences and Environment, Roskilde University, Roskilde, Denmark
| | | | - Lotte Jelsbak
- Department of Sciences and Environment, Roskilde University, Roskilde, Denmark.
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48
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Ruddle SJ, Massis LM, Cutter AC, Monack DM. Salmonella-liberated dietary L-arabinose promotes expansion in superspreaders. Cell Host Microbe 2023; 31:405-417.e5. [PMID: 36812913 PMCID: PMC10016319 DOI: 10.1016/j.chom.2023.01.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/23/2022] [Accepted: 01/27/2023] [Indexed: 02/24/2023]
Abstract
The molecular understanding of host-pathogen interactions in the gastrointestinal (GI) tract of superspreader hosts is incomplete. In a mouse model of chronic, asymptomatic Salmonella enterica serovar Typhimurium (S. Tm) infection, we performed untargeted metabolomics on the feces of mice and found that superspreader hosts possess distinct metabolic signatures compared with non-superspreaders, including differential levels of L-arabinose. RNA-seq on S. Tm from superspreader fecal samples showed increased expression of the L-arabinose catabolism pathway in vivo. By combining bacterial genetics and diet manipulation, we demonstrate that diet-derived L-arabinose provides S. Tm a competitive advantage in the GI tract, and expansion of S. Tm in the GI tract requires an alpha-N-arabinofuranosidase that liberates L-arabinose from dietary polysaccharides. Ultimately, our work shows that pathogen-liberated L-arabinose from the diet provides a competitive advantage to S. Tm in vivo. These findings propose L-arabinose as a critical driver of S. Tm expansion in the GI tracts of superspreader hosts.
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Affiliation(s)
- Sarah J Ruddle
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Liliana M Massis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alyssa C Cutter
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Denise M Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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49
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Improved Bacterial Single-Cell RNA-Seq through Automated MATQ-Seq and Cas9-Based Removal of rRNA Reads. mBio 2023; 14:e0355722. [PMID: 36880749 PMCID: PMC10127585 DOI: 10.1128/mbio.03557-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023] Open
Abstract
Bulk RNA sequencing technologies have provided invaluable insights into host and bacterial gene expression and associated regulatory networks. Nevertheless, the majority of these approaches report average expression across cell populations, hiding the true underlying expression patterns that are often heterogeneous in nature. Due to technical advances, single-cell transcriptomics in bacteria has recently become reality, allowing exploration of these heterogeneous populations, which are often the result of environmental changes and stressors. In this work, we have improved our previously published bacterial single-cell RNA sequencing (scRNA-seq) protocol that is based on multiple annealing and deoxycytidine (dC) tailing-based quantitative scRNA-seq (MATQ-seq), achieving a higher throughput through the integration of automation. We also selected a more efficient reverse transcriptase, which led to reduced cell loss and higher workflow robustness. Moreover, we successfully implemented a Cas9-based rRNA depletion protocol into the MATQ-seq workflow. Applying our improved protocol on a large set of single Salmonella cells sampled over different growth conditions revealed improved gene coverage and a higher gene detection limit compared to our original protocol and allowed us to detect the expression of small regulatory RNAs, such as GcvB or CsrB at a single-cell level. In addition, we confirmed previously described phenotypic heterogeneity in Salmonella in regard to expression of pathogenicity-associated genes. Overall, the low percentage of cell loss and high gene detection limit makes the improved MATQ-seq protocol particularly well suited for studies with limited input material, such as analysis of small bacterial populations in host niches or intracellular bacteria. IMPORTANCE Gene expression heterogeneity among isogenic bacteria is linked to clinically relevant scenarios, like biofilm formation and antibiotic tolerance. The recent development of bacterial single-cell RNA sequencing (scRNA-seq) enables the study of cell-to-cell variability in bacterial populations and the mechanisms underlying these phenomena. Here, we report a scRNA-seq workflow based on MATQ-seq with increased robustness, reduced cell loss, and improved transcript capture rate and gene coverage. Use of a more efficient reverse transcriptase and the integration of an rRNA depletion step, which can be adapted to other bacterial single-cell workflows, was instrumental for these improvements. Applying the protocol to the foodborne pathogen Salmonella, we confirmed transcriptional heterogeneity across and within different growth phases and demonstrated that our workflow captures small regulatory RNAs at a single-cell level. Due to low cell loss and high transcript capture rates, this protocol is uniquely suited for experimental settings in which the starting material is limited, such as infected tissues.
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Iwadate Y, Golubeva YA, Slauch JM. Cation Homeostasis: Coordinate Regulation of Polyamine and Magnesium Levels in Salmonella. mBio 2023; 14:e0269822. [PMID: 36475749 PMCID: PMC9972920 DOI: 10.1128/mbio.02698-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/14/2022] [Indexed: 12/13/2022] Open
Abstract
Polyamines are organic cations that are important in all domains of life. Here, we show that in Salmonella, polyamine levels and Mg2+ levels are coordinately regulated and that this regulation is critical for viability under both low and high concentrations of polyamines. Upon Mg2+ starvation, polyamine synthesis is induced, as is the production of the high-affinity Mg2+ transporters MgtA and MgtB. Either polyamine synthesis or Mg2+ transport is required to maintain viability. Mutants lacking the polyamine exporter PaeA, the expression of which is induced by PhoPQ in response to low Mg2+, lose viability in the stationary phase. This lethality is suppressed by blocking either polyamine synthesis or Mg2+ transport, suggesting that once Mg2+ levels are reestablished, the excess polyamines must be excreted. Thus, it is the relative levels of both Mg2+ and polyamines that are regulated to maintain viability. Indeed, sensitivity to high concentrations of polyamines is proportional to the Mg2+ levels in the medium. These results are recapitulated during infection. Polyamine synthesis mutants are attenuated in a mouse model of systemic infection, as are strains lacking the MgtB Mg2+ transporter. The loss of MgtB in the synthesis mutant background confers a synthetic phenotype, confirming that Mg2+ and polyamines are required for the same process(es). Mutants lacking PaeA are also attenuated, but deleting paeA has no phenotype in a polyamine synthesis mutant background. These data support the idea that the cell coordinately controls both the polyamine and Mg2+ concentrations to maintain overall cation homeostasis, which is critical for survival in the macrophage phagosome. IMPORTANCE Polyamines are organic cations that are important in all life forms and are essential in plants and animals. However, their physiological functions and regulation remain poorly understood. We show that polyamines are critical for the adaptation of Salmonella to low Mg2+ conditions, including those found in the macrophage phagosome. Polyamines are synthesized upon low Mg2+ stress and partially replace Mg2+ until cytoplasmic Mg2+ levels are restored. Indeed, it is the sum of Mg2+ and polyamines in the cell that is critical for viability. While Mg2+ and polyamines compensate for one another, too little of both or too much of both is lethal. After cytoplasmic Mg2+ levels are reestablished, polyamines must be exported to avoid the toxic effects of excess divalent cations.
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Affiliation(s)
- Yumi Iwadate
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Yekaterina A. Golubeva
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - James M. Slauch
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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