1
|
Hart MT, Rom JS, Le Breton Y, Hause LL, Belew AT, El-Sayed NM, McIver KS. The Streptococcus pyogenes stand-alone regulator RofA exhibits characteristics of a PRD-containing virulence regulator. Infect Immun 2024; 92:e0008324. [PMID: 38712951 PMCID: PMC11237776 DOI: 10.1128/iai.00083-24] [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: 02/23/2024] [Accepted: 04/09/2024] [Indexed: 05/08/2024] Open
Abstract
Streptococcus pyogenes [group A streptococcus (GAS)] is a human pathogen capable of infecting diverse tissues. To successfully infect these sites, GAS must detect available nutrients and adapt accordingly. The phosphoenolpyruvate transferase system (PTS) mediates carbohydrate uptake and metabolic gene regulation to adapt to the nutritional environment. Regulation by the PTS can occur through phosphorylation of transcriptional regulators at conserved PTS-regulatory domains (PRDs). GAS has several PRD-containing stand-alone regulators with regulons encoding both metabolic genes and virulence factors [PRD-containing virulence regulators (PCVRs)]. One is RofA, which regulates the expression of virulence genes in multiple GAS serotypes. It was hypothesized that RofA is phosphorylated by the PTS in response to carbohydrate levels to coordinate virulence gene expression. In this study, the RofA regulon of M1T1 strain 5448 was determined using RNA sequencing. Two operons were consistently differentially expressed across growth in the absence of RofA; the pilus operon was downregulated, and the capsule operon was upregulated. This correlated with increased capsule production and decreased adherence to keratinocytes. Purified RofA-His was phosphorylated in vitro by PTS proteins EI and HPr, and phosphorylated RofA-FLAG was detected in vivo when GAS was grown in low-glucose C medium. Phosphorylated RofA was not observed when C medium was supplemented 10-fold with glucose. Mutations of select histidine residues within the putative PRDs contributed to the in vivo phosphorylation of RofA, although phosphorylation of RofA was still observed, suggesting other phosphorylation sites exist in the protein. Together, these findings support the hypothesis that RofA is a PCVR that may couple sugar metabolism with virulence regulation.
Collapse
Affiliation(s)
- Meaghan T Hart
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
| | - Joseph S Rom
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
| | - Yoann Le Breton
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
| | - Lara L Hause
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
| | - Ashton T Belew
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, USA
| | - Najib M El-Sayed
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, USA
| | - Kevin S McIver
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, College Park, Maryland, USA
| |
Collapse
|
2
|
Sangiorgio G, Calvo M, Migliorisi G, Campanile F, Stefani S. The Impact of Enterococcus spp. in the Immunocompromised Host: A Comprehensive Review. Pathogens 2024; 13:409. [PMID: 38787261 PMCID: PMC11124283 DOI: 10.3390/pathogens13050409] [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: 04/20/2024] [Revised: 05/05/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
The immunocompromised host is usually vulnerable to infectious diseases due to broad-spectrum treatments and immunological dysregulation. The Enterococcus genus consists of normal gut commensals, which acquire a leading role in infective processes among individuals with compromised immune systems. These microorganisms may express a potential virulence and resistance spectrum, enabling their function as severe pathogens. The Enterococcus spp. infections in immunocompromised hosts appear to be difficult to resolve due to the immunological response impairment and the possibility of facing antimicrobial-resistant strains. As regards the related risk factors, several data demonstrated that prior antibiotic exposure, medical device insertion, prolonged hospitalization and surgical interventions may lead to Enterococcus overgrowth, antibiotic resistance and spread among critical healthcare settings. Herein, we present a comprehensive review of Enterococcus spp. in the immunocompromised host, summarizing the available knowledge about virulence factors, antimicrobial-resistance mechanisms and host-pathogen interaction. The review ultimately yearns for more substantial support to further investigations about enterococcal infections and immunocompromised host response.
Collapse
Affiliation(s)
- Giuseppe Sangiorgio
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
| | - Maddalena Calvo
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| | - Giuseppe Migliorisi
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| | - Floriana Campanile
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| |
Collapse
|
3
|
Wu J, Wang C, O'Byrne C. Metabolic reprogramming in the food-borne pathogen Listeria monocytogenes as a critical defence against acid stress. FEMS Microbiol Lett 2024; 371:fnae060. [PMID: 39118365 PMCID: PMC11334721 DOI: 10.1093/femsle/fnae060] [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: 03/07/2024] [Revised: 05/29/2024] [Accepted: 08/07/2024] [Indexed: 08/10/2024] Open
Abstract
The ability to sense and respond effectively to acidic stress is important for microorganisms to survive and proliferate in fluctuating environments. As specific metabolic activities can serve to buffer the cytoplasmic pH, microorganisms rewire their metabolism to favour these reactions and thereby mitigate acid stress. The orally acquired pathogen Listeria monocytogenes exploits alternative metabolic activities to overcome the acidic stress encountered in the human stomach or food products. In this minireview, we discuss the metabolic processes in L. monocytogenes that mitigate acid stress, with an emphasis on the proton-depleting reactions, including glutamate decarboxylation, arginine/agmatine deimination, and fermentative acetoin production. We also summarize the recent findings on regulatory mechanisms that control the expression of genes that are responsible for these metabolic activities, including the general stress response regulator SigB, arginine repressor ArgR, and the recently discovered RofA-like transcriptional regulatory GadR. We further discuss the importance of this metabolic reprogramming in the context of food products and within the host. Finally, we highlight some outstanding challenges in the field, including an understanding of acid-sensing mechanisms, the role of intraspecies heterogeneity in acid resistance, and how a fundamental understanding of acid stress response can be exploited for food formulation to improve food safety and reduce food waste.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, H91 TK33, Galway, Ireland
| | - Chuhan Wang
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, H91 TK33, Galway, Ireland
| | - Conor O'Byrne
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, H91 TK33, Galway, Ireland
| |
Collapse
|
4
|
Wu J, McAuliffe O, O'Byrne CP. A novel RofA-family transcriptional regulator, GadR, controls the development of acid resistance in Listeria monocytogenes. mBio 2023; 14:e0171623. [PMID: 37882515 PMCID: PMC10746197 DOI: 10.1128/mbio.01716-23] [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: 07/04/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The ability to survive the acidic conditions found in the stomach is crucial for the food-borne pathogen Listeria monocytogenes to gain access to the mammalian gastrointestinal tract. Little is currently known about how acid resistance is regulated in this pathogen and why this trait is highly variable between strains. Here, we used comparative genomics to identify a novel RofA-family transcriptional regulator, GadR, that controls the development of acid resistance. The RofA family of regulators was previously found only in a small group of bacterial pathogens, including streptococci, where they regulate virulence properties. We show that gadR encodes the dominant regulator of acid resistance in L. monocytogenes and that its sequence variability accounts for previously observed differences between strains in this trait. Together, these findings significantly advance our understanding of how this important pathogen copes with acid stress and suggest a potential molecular target to aid its control in the food chain.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Olivia McAuliffe
- Department of Food Biosciences, Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Conor P. O'Byrne
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| |
Collapse
|
5
|
Horng YT, Panjaitan NSD, Tsai YJ, Su PW, Yang HC, Soo PC. The role of EII complex in the bacterial responses to the glucose-survey in clinical Klebsiella pneumoniae isolates. PLoS One 2023; 18:e0289759. [PMID: 37549172 PMCID: PMC10406186 DOI: 10.1371/journal.pone.0289759] [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: 05/11/2023] [Accepted: 07/24/2023] [Indexed: 08/09/2023] Open
Abstract
Type 3 fimbriae in Klebsiella pneumoniae are important for bacterial colonization on abiotic and biotic surfaces. The major subunit of type 3 fimbriae (MrkA) is increased by overexpression of EtcABC, an EII complex of phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs), through cAMP-cAMP receptor protein (cAMP-CRP) in K. pneumoniae STU1. Here, we further characterized the relations between the amount of etcABC mRNA and MrkA in 78 clinical K. pneumoniae isolates incubated in high levels of glucose. By Western blotting, we observed that MrkA of 29 isolates were not decreased much by high levels of glucose (Group A) but MrkA of other 49 isolates were significantly reduced (Group B) in the same condition. The bacterial biofilms on abiotic surfaces and colonization in the Caenorhabditis elegans of representative isolates in the Group A were not affected by high levels of glucose. However, the biofilm and colonization in the worm of clinical isolates in the Group B were much reduced by high levels of glucose. After quantification by real time RT-PCR, 76% of Group A but just 10% of Group B showed high amount of etcA mRNA. In summary, our results suggested that for most of K. pneumoniae clinical isolates, the amount of etcABC mRNA was positively related to their type 3 fimbriae production in a high level of glucose, thereby to their biofilm formation and colonization in the worm.
Collapse
Affiliation(s)
- Yu-Tze Horng
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Novaria Sari Dewi Panjaitan
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
- Center for Biomedical Research, Research Organization for Health, National Research and Innovation Agency (BRIN), Cibinong Science Center, Cibinong, Bogor, West Java, Indonesia
| | - Yi-Jhen Tsai
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Pin-Wei Su
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Hung-Chi Yang
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan, R.O.C
| | - Po-Chi Soo
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| |
Collapse
|
6
|
Li HK, Zhi X, Vieira A, Whitwell HJ, Schricker A, Jauneikaite E, Li H, Yosef A, Andrew I, Game L, Turner CE, Lamagni T, Coelho J, Sriskandan S. Characterization of emergent toxigenic M1 UK Streptococcus pyogenes and associated sublineages. Microb Genom 2023; 9:mgen000994. [PMID: 37093716 PMCID: PMC10210942 DOI: 10.1099/mgen.0.000994] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/23/2023] [Indexed: 04/25/2023] Open
Abstract
Streptococcus pyogenes genotype emm1 is a successful, globally distributed epidemic clone that is regarded as inherently virulent. An emm1 sublineage, M1UK, that produces increased levels of SpeA toxin was associated with increased scarlet fever and invasive infections in England in 2015/2016. Defined by 27 SNPs in the core genome, M1UK is now dominant in England. To more fully characterize M1UK, we undertook comparative transcriptomic and proteomic analyses of M1UK and contemporary non-M1UK emm1 strains (M1global). Just seven genes were differentially expressed by M1UK compared with contemporary M1global strains. In addition to speA, five genes in the operon that includes glycerol dehydrogenase were upregulated in M1UK (gldA, mipB/talC, pflD, and phosphotransferase system IIC and IIB components), while aquaporin (glpF2) was downregulated. M1UK strains have a stop codon in gldA. Deletion of gldA in M1global abrogated glycerol dehydrogenase activity, and recapitulated upregulation of gene expression within the operon that includes gldA, consistent with a feedback effect. Phylogenetic analysis identified two intermediate emm1 sublineages in England comprising 13/27 (M113SNPs) and 23/27 SNPs (M123SNPs), respectively, that had failed to expand in the population. Proteomic analysis of invasive strains from the four phylogenetic emm1 groups highlighted sublineage-specific changes in carbohydrate metabolism, protein synthesis and protein processing; upregulation of SpeA was not observed in chemically defined medium. In rich broth, however, expression of SpeA was upregulated ~10-fold in both M123SNPs and M1UK sublineages, compared with M113SNPs and M1global. We conclude that stepwise accumulation of SNPs led to the emergence of M1UK. While increased expression of SpeA is a key indicator of M1UK and undoubtedly important, M1UK strains have outcompeted M123SNPs and other emm types that produce similar or more superantigen toxin. We speculate that an accumulation of adaptive SNPs has contributed to a wider fitness advantage in M1UK on an inherently successful emm1 streptococcal background.
Collapse
Affiliation(s)
- Ho Kwong Li
- Department of Infectious Disease, Imperial College London, London, UK
- MRC Centre for Molecular Bacteriology & Infection (CMBI), Imperial College London, London, UK
| | - Xiangyun Zhi
- Department of Infectious Disease, Imperial College London, London, UK
- MRC Centre for Molecular Bacteriology & Infection (CMBI), Imperial College London, London, UK
| | - Ana Vieira
- Department of Infectious Disease, Imperial College London, London, UK
- MRC Centre for Molecular Bacteriology & Infection (CMBI), Imperial College London, London, UK
| | - Harry J. Whitwell
- National Phenome Centre and Imperial Clinical Phenotyping Centre, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Amelia Schricker
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, London, UK
| | - Elita Jauneikaite
- NIHR Health Protection Unit in Healthcare-associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
- School of Public Health, Imperial College London, London, UK
| | - Hanqi Li
- Department of Infectious Disease, Imperial College London, London, UK
| | - Ahmed Yosef
- Department of Infectious Disease, Imperial College London, London, UK
| | - Ivan Andrew
- Genomics Facility, UKRI-MRC London Institute for Medical Sciences (LMS), Imperial College London, London, UK
| | - Laurence Game
- Genomics Facility, UKRI-MRC London Institute for Medical Sciences (LMS), Imperial College London, London, UK
| | - Claire E. Turner
- The Florey Institute, School of Biosciences, University of Sheffield, South Yorkshire, UK
| | - Theresa Lamagni
- NIHR Health Protection Unit in Healthcare-associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
- Centre for Infections, UK Health Security Agency, London, UK
| | - Juliana Coelho
- NIHR Health Protection Unit in Healthcare-associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
- Centre for Infections, UK Health Security Agency, London, UK
| | - Shiranee Sriskandan
- Department of Infectious Disease, Imperial College London, London, UK
- MRC Centre for Molecular Bacteriology & Infection (CMBI), Imperial College London, London, UK
- NIHR Health Protection Unit in Healthcare-associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
| |
Collapse
|
7
|
Suo W, Guo X, Zhang X, Xiao S, Wang S, Yin Y, Zheng Y. Glucose levels affect MgaSpn regulation on the virulence and adaptability of Streptococcus pneumoniae. Microb Pathog 2023; 174:105896. [PMID: 36460142 DOI: 10.1016/j.micpath.2022.105896] [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: 09/20/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022]
Abstract
Streptococcus pneumoniae can regulate virulence gene expression by sensing environmental changes, which is key to its pathogenicity. The global transcription regulator MgaSpn of Streptococcus pneumoniae regulates virulence genes expression by directly binding to the promoter regions, but its role in response to different environments remains unclear. In this study, we found that glucose levels could affect phosphocholine content, which was mediated by MgaSpn. MgaSpn can also alter its anti-phagocytosis ability, depending on the availability of glucose. In addition, transcriptome analysis of wild-type D39s in low and high glucose concentrations revealed that MgaSpn was also involved in the regulation of carbon metabolism inhibition (carbon catabolite repression; CCR) and translation processes, which made S. pneumoniae highly competitive in fluctuating environments. In conclusion, MgaSpn is closely related to the virulence and environmental adaptability of Streptococcus pneumoniae.
Collapse
Affiliation(s)
- Weicai Suo
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, and Chongqing Key Laboratory of Pediatrics, Chongqing, PR China
| | - Xinlin Guo
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, and Chongqing Key Laboratory of Pediatrics, Chongqing, PR China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, PR China
| | - Shengnan Xiao
- Precision Medicine Center, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
| | - Shuhui Wang
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, and Chongqing Key Laboratory of Pediatrics, Chongqing, PR China
| | - Yibing Yin
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, PR China
| | - Yuqiang Zheng
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, and Chongqing Key Laboratory of Pediatrics, Chongqing, PR China.
| |
Collapse
|
8
|
Mucci NC, Jones KA, Cao M, Wyatt MR, Foye S, Kauffman SJ, Richards GR, Taufer M, Chikaraishi Y, Steffan SA, Campagna SR, Goodrich-Blair H. Apex Predator Nematodes and Meso-Predator Bacteria Consume Their Basal Insect Prey through Discrete Stages of Chemical Transformations. mSystems 2022; 7:e0031222. [PMID: 35543104 PMCID: PMC9241642 DOI: 10.1128/msystems.00312-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 11/20/2022] Open
Abstract
Microbial symbiosis drives physiological processes of higher-order systems, including the acquisition and consumption of nutrients that support symbiotic partner reproduction. Metabolic analytics provide new avenues to examine how chemical ecology, or the conversion of existing biomass to new forms, changes over a symbiotic life cycle. We applied these approaches to the nematode Steinernema carpocapsae, its mutualist bacterium, Xenorhabdus nematophila, and the insects they infect. The nematode-bacterium pair infects, kills, and reproduces in an insect until nutrients are depleted. To understand the conversion of insect biomass over time into either nematode or bacterium biomass, we integrated information from trophic, metabolomic, and gene regulation analyses. Trophic analysis established bacteria as meso-predators and primary insect consumers. Nematodes hold a trophic position of 4.6, indicative of an apex predator, consuming bacteria and likely other nematodes. Metabolic changes associated with Galleria mellonella insect bioconversion were assessed using multivariate statistical analyses of metabolomics data sets derived from sampling over an infection time course. Statistically significant, discrete phases were detected, indicating the insect chemical environment changes reproducibly during bioconversion. A novel hierarchical clustering method was designed to probe molecular abundance fluctuation patterns over time, revealing distinct metabolite clusters that exhibit similar abundance shifts across the time course. Composite data suggest bacterial tryptophan and nematode kynurenine pathways are coordinated for reciprocal exchange of tryptophan and NAD+ and for synthesis of intermediates that can have complex effects on bacterial phenotypes and nematode behaviors. Our analysis of pathways and metabolites reveals the chemistry underlying the recycling of organic material during carnivory. IMPORTANCE The processes by which organic life is consumed and reborn in a complex ecosystem were investigated through a multiomics approach applied to the tripartite Xenorhabdus bacterium-Steinernema nematode-Galleria insect symbiosis. Trophic analyses demonstrate the primary consumers of the insect are the bacteria, and the nematode in turn consumes the bacteria. This suggests the Steinernema-Xenorhabdus mutualism is a form of agriculture in which the nematode cultivates the bacterial food sources by inoculating them into insect hosts. Metabolomics analysis revealed a shift in biological material throughout progression of the life cycle: active infection, insect death, and conversion of cadaver tissues into bacterial biomass and nematode tissue. We show that each phase of the life cycle is metabolically distinct, with significant differences including those in the tricarboxylic acid cycle and amino acid pathways. Our findings demonstrate that symbiotic life cycles can be defined by reproducible stage-specific chemical signatures, enhancing our broad understanding of metabolic processes that underpin a three-way symbiosis.
Collapse
Affiliation(s)
- Nicholas C. Mucci
- Department of Microbiology, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
| | - Katarina A. Jones
- Department of Chemistry, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
| | - Mengyi Cao
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Michael R. Wyatt
- Department of Electrical Engineering and Computer Science, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
| | - Shane Foye
- Department of Entomology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Sarah J. Kauffman
- Department of Microbiology, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
| | - Gregory R. Richards
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Michela Taufer
- Department of Electrical Engineering and Computer Science, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
| | - Yoshito Chikaraishi
- Institute of Low Temperature Science, Hokkaido University, Japan
- Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology, Japan
| | - Shawn A. Steffan
- Department of Entomology, University of Wisconsin–Madison, Madison, Wisconsin, USA
- U.S. Department of Agriculture, Agricultural Research Service, Madison, Wisconsin, USA
| | - Shawn R. Campagna
- Department of Chemistry, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
- Biological and Small Molecule Mass Spectrometry Core, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
| | - Heidi Goodrich-Blair
- Department of Microbiology, University of Tennessee–Knoxville, Knoxville, Tennessee, USA
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| |
Collapse
|
9
|
Expression of the Bacillus thuringiensis vip3A Insecticidal Toxin Gene Is Activated at the Onset of Stationary Phase by VipR, an Autoregulated Transcription Factor. Microbiol Spectr 2022; 10:e0120522. [PMID: 35727045 PMCID: PMC9430311 DOI: 10.1128/spectrum.01205-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The Vegetative insecticidal protein Vip3A is produced by some Bacillus thuringiensis strains from the mid-log growth phase to sporulation. Although Vip3A is important for the entomopathogenicity of B. thuringiensis, the vip3A gene regulation is unknown. In the B. thuringiensis serovar kurstaki HD1 strain, vip3A is carried by the pBMB299 plasmid, which is absent in the closely related strain B. thuringiensis kurstaki HD73. Using a transcriptional fusion between the vip3A promoter and lacZ, we observed that the HD73 strain is unable to express vip3A. This result suggests that a specific regulator is required for vip3A expression. Assuming that the regulator gene is located on the same plasmid as vip3A, we transferred pBMB299 from the HD1 strain to the HD73 strain. We found that Vip3A was produced in the HD73 strain containing pBMB299, suggesting that the regulator gene is located on this plasmid. Using this heterologous host and promoter-lacZ transcription fusions, we showed that a specific regulator, VipR, is essential to activate vip3A expression at the onset of stationary phase. We demonstrated that vipR transcription is positively autoregulated and the determination of the vipR and vip3A promoters pinpointed a putative VipR target upstream from the Sigma A-specific −10 region of these two promoters. Surprisingly, this conserved sequence was also found upstream of cry1I and cry2 genes. Finally, we showed that vip3A and vipR expression is increased drastically in a Δspo0A mutant unable to initiate sporulation. In conclusion, we have characterized a novel regulator involved in the entomopathogenic potency of B. thuringiensis through a sporulation-independent pathway. IMPORTANCE The insecticidal properties of Bacillus thuringiensis are due mainly to Cry toxins which form a crystalline inclusion during sporulation. However, other proteins participate in the pathogenicity of the bacterium, notably, the Vip3A toxins that are produced from vegetative growth to sporulation. The VipR regulator that activates vip3A gene expression at the onset of stationary phase is positively autoregulated, and an analysis of the promoter region of the vip3A and vipR genes reveals the presence of a highly conserved DNA sequence. This possible VipR target sequence is also found upstream of the cry2A and cry1I genes, suggesting that Cry toxins can be produced before the bacteria enter sporulation. Such a result could allow us to better understand the role of Cry and Vip3A toxins during the B. thuringiensis infectious cycle in insects, in addition to the primary role of the Cry toxins in the toxemia caused by ingestion of crystals.
Collapse
|
10
|
Wang R, Li H, Liu Y, Chen J, Peng F, Jiang Z, Liu J, Song H. Efficient removal of azo dyes by Enterococcus faecalis R1107 and its application in simulated textile effluent treatment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 238:113577. [PMID: 35526458 DOI: 10.1016/j.ecoenv.2022.113577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/14/2022] [Accepted: 04/27/2022] [Indexed: 06/14/2023]
Abstract
This study aimed to exploit the potential of Enterococcus faecalis R1107 in the bioremediation of azo dyes. The maximal decolorization of Congo Red (CR), Reactive Black 5 (RB5), and Direct Black 38 (DB38) were 90.17%, 96.82%, and 81.95%, respectively, with the bacterial treatment for 48 h. 65.57% of CR and 72.64% of RB5 could be decolorized by E. faecalis R1107 within 48 h when the concentration of azo dyes increased up to 1000 mg/L. FTIR analysis confirmed that E. faecalis R1107 could effectively break down the chemical structures of three azo dyes. E. faecalis R1107 alleviated the phytotoxicity of azo dyes and improved seed germination, which contributed to the increase in the lengths of roots, stems, and leaves of Vigna radiata seedlings. Transcriptomic analysis suggested that the gene regulatory networks in E. faecalis R1107 synergistically improved the degradation and detoxification of RB5, including the major metabolic pathways, the secondary metabolism, the transport system, the amino acid metabolic pathways, and the signal transduction systems. Simulated textile effluent (STE) was used to mimic real textile effluent to evaluate the bioremediation potential of E. faecalis R1107, and 72.79% STE can be decolorized after E. faecalis R1107 treatment for 48 h. In summary, our study demonstrated that E. faecalis R1107 might be well suitable for potential applications in the bioremediation of textile effluent.
Collapse
Affiliation(s)
- Rui Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Huanan Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Yanfang Liu
- Hubei Academy of Scientific and Technical Information, Wuhan 430071, PR China
| | - Jianhui Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Fang Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, PR China
| | - Zhengbing Jiang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Jiashu Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China.
| | - Huiting Song
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, PR China.
| |
Collapse
|