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Rojas VK, Winter MG, Jimenez AG, Tanner NW, Crockett SL, Spiga L, Hendrixson DR, Winter SE. Infection-associated gene regulation of L-tartrate metabolism in Salmonella enterica serovar Typhimurium. mBio 2024; 15:e0035024. [PMID: 38682906 DOI: 10.1128/mbio.00350-24] [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: 02/02/2024] [Accepted: 03/28/2024] [Indexed: 05/01/2024] Open
Abstract
Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for the sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, the regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, i.e., substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes the utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection. IMPORTANCE Bacterial pathogens must adapt their gene expression profiles to cope with diverse environments encountered during infection. This coordinated process is carried out by the integration of cues that the pathogen senses to fine-tune gene expression in a spatiotemporal manner. Many studies have elucidated the regulatory mechanisms of how Salmonella sense metabolites in the gut to activate or repress its virulence program; however, our understanding of how Salmonella coordinates its gene expression to maximize the utilization of carbon and energy sources found in transitional nutrient niches is not well understood. In this study, we discovered how Salmonella integrates two infection-relevant cues, substrate availability and exogenous electron acceptors, to control L-tartrate metabolism. From our experiments, we propose a model for how L-tartrate metabolism is regulated in response to different metabolic cues in addition to characterizing two previously unknown transcriptional regulators. This study expands our understanding of how microbes combine metabolic cues to enhance fitness during infection.
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Affiliation(s)
- Vivian K Rojas
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
| | - Maria G Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
| | - Angel G Jimenez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Natasha W Tanner
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
| | - Stacey L Crockett
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Luisella Spiga
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Sebastian E Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
- Department of Medical Microbiology and Immunology, UC Davis School of Medicine, Davis, California, USA
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2
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Ma K, Chinelo OR, Gu M, Kong F, Jiang Y, Wang H, Xue T. Role of ArcA in the regulation of antibiotic sensitivity in avian pathogenic Escherichia coli. Poult Sci 2024; 103:103686. [PMID: 38574461 PMCID: PMC11004985 DOI: 10.1016/j.psj.2024.103686] [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: 02/06/2024] [Revised: 03/16/2024] [Accepted: 03/18/2024] [Indexed: 04/06/2024] Open
Abstract
Avian pathogenic Escherichia coli (APEC) is one of the common extraintestinal infectious disease pathogens in chickens, geese, and other birds, inducing serious impediments to the development of the poultry industry. Hence, investigating how bacteria regulate themselves amidst different challenging conditions is immense essential in prevention and treatment for bacterial pathogen infections. The ArcA regulatory factor has been reported to regulate oxygen availability in strains, but its role in regulation of antibiotics resistance in APEC is unclear. This study delved into understanding how ArcA regulates antibiotic resistance in APEC. An E. coli APEC40 arcA knockout strain was constructed, and the regulatory mechanism of arcA on APEC antibiotic susceptibility was identified by drug sensitivity test, colony counting assay, real-time quantitative PCR, β-galactosidase assays and electrophoretic mobility shift assay (EMSA). The results showed that ArcA directly binds to the promoter region of the outer membrane protein OmpC/OmpW and regulates bacterial susceptibility to kanamycin and penicillin G. At the same time, the double knockout of ompW and ompW/arcA resulted in an increase in resistance to kanamycin compared to the deletion of the arcA gene. This outcome provided experimental proof suggesting that the outer membrane protein OmpW could serve as a crucial pathway for the ingress of kanamycin into cells. These results confirmed the important regulatory role of ArcA transcription factors under APEC antibiotic stress.
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Affiliation(s)
- Kai Ma
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Okoro Ruth Chinelo
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Mantian Gu
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Fanwenqing Kong
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Ying Jiang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Hui Wang
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China.
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Dong T, Zhang L, Hao S, Yang J, Peng Y. Interspecies cooperation-driven photogenerated electron transfer processes and efficient multi-pathway nitrogen removal in the g-C 3N 4-anammox consortia biohybrid system. WATER RESEARCH 2024; 255:121532. [PMID: 38564893 DOI: 10.1016/j.watres.2024.121532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/04/2024]
Abstract
Photocatalytic materials-microbial biohybrid systems pave the way for solar-driven wastewater nitrogen removal. In this study, interspecies cooperation in photogenerated electron transfer and efficient nitrogen removal mechanism in the g-C3N4-anammox consortia biohybrid system were first deciphered. The results indicated that the essential extracellular electron carriers (cytochrome c and flavin) for anammox genomes were provided by associated bacteria (BACT3 and CHLO2). This cooperation, regulated by the ArcAB system and electron transfer flavoprotein, made anammox bacteria the primary photogenerated electron sink. Furthermore, an efficient photogenerated electron harness was used to construct a reductive glycine pathway (rGlyP) in anammox bacteria inventively, which coexisted with the Wood-Ljungdahl pathway (WLP), constituting a dual-pathway carbon fixation model, rGlyP-WLP. Carbon fixation products efficiently contributed to the tricarboxylic acid cycle, while inhibiting electron diversion in anabolism. Photogenerated electrons were targeted channeled into nitrogen metabolism-available electron carriers, enhancing anammox and dissimilatory nitrate reduction to ammonium (DNRA) processes. Moreover, ammonia assimilation by the glycine cleavage system in rGlyP established an alternative ammonia removal route. Ultimately, multi-pathway nitrogen removal involving anammox, DNRA, and rGlyP achieved 100 % ammonia removal and 94.25 % total nitrogen removal efficiency. This study has expanded understanding of anammox metabolic diversity, enhancing its potential application in carbon-neutral wastewater treatment.
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Affiliation(s)
- Tingjun Dong
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing, 100124, China
| | - Li Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing, 100124, China.
| | - Shiwei Hao
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing, 100124, China
| | - Jiachun Yang
- China Coal Technology & Engineering Group Co. Ltd., Tokyo, 100-0011, Japan
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing, 100124, China
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Yoshidome D, Hidaka M, Miyanaga T, Ito Y, Kosono S, Nishiyama M. Glutamate production from aerial nitrogen using the nitrogen-fixing bacterium Klebsiella oxytoca. Commun Biol 2024; 7:443. [PMID: 38605181 PMCID: PMC11009414 DOI: 10.1038/s42003-024-06147-z] [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: 10/03/2023] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
Glutamate is an essential biological compound produced for various therapeutic and nutritional applications. The current glutamate production process requires a large amount of ammonium, which is generated through the energy-consuming and CO2-emitting Haber-Bosch process; therefore, the development of bio-economical glutamate production processes is required. We herein developed a strategy for glutamate production from aerial nitrogen using the nitrogen-fixing bacterium Klebsiella oxytoca. We showed that a simultaneous supply of glucose and citrate as carbon sources enhanced the nitrogenase activity of K. oxytoca. In the presence of glucose and citrate, K. oxytoca strain that was genetically engineered to increase the supply of 2-oxoglutarate, a precursor of glutamate synthesis, produced glutamate extracellularly more than 1 g L-1 from aerial nitrogen. This strategy offers a sustainable and eco-friendly manufacturing process to produce various nitrogen-containing compounds using aerial nitrogen.
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Affiliation(s)
- Daisuke Yoshidome
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
| | - Makoto Hidaka
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Toka Miyanaga
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yusuke Ito
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Kikkoman Corporation, Noda, Chiba, Japan
| | - Saori Kosono
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
| | - Makoto Nishiyama
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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Brannon JR, Reasoner SA, Bermudez TA, Comer SL, Wiebe MA, Dunigan TL, Beebout CJ, Ross T, Bamidele A, Hadjifrangiskou M. Mapping niche-specific two-component system requirements in uropathogenic Escherichia coli. Microbiol Spectr 2024; 12:e0223623. [PMID: 38385738 PMCID: PMC10986536 DOI: 10.1128/spectrum.02236-23] [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: 05/26/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024] Open
Abstract
Sensory systems allow pathogens to differentiate between different niches and respond to stimuli within them. A major mechanism through which bacteria sense and respond to stimuli in their surroundings is two-component systems (TCSs). TCSs allow for the detection of multiple stimuli to lead to a highly controlled and rapid change in gene expression. Here, we provide a comprehensive list of TCSs important for the pathogenesis of uropathogenic Escherichia coli (UPEC). UPEC accounts for >75% of urinary tract infections (UTIs) worldwide. UTIs are most prevalent among people assigned female at birth, with the vagina becoming colonized by UPEC in addition to the gut and the bladder. In the bladder, adherence to the urothelium triggers E. coli invasion of bladder cells and an intracellular pathogenic cascade. Intracellular E. coli are safely hidden from host neutrophils, competition from the microbiota, and antibiotics that kill extracellular E. coli. To survive in these intimately connected, yet physiologically diverse niches E. coli must rapidly coordinate metabolic and virulence systems in response to the distinct stimuli encountered in each environment. We hypothesized that specific TCSs allow UPEC to sense these diverse environments encountered during infection with built-in redundant safeguards. Here, we created a library of isogenic TCS deletion mutants that we leveraged to map distinct TCS contributions to infection. We identify-for the first time-a comprehensive panel of UPEC TCSs that are critical for infection of the genitourinary tract and report that the TCSs mediating colonization of the bladder, kidneys, or vagina are distinct.IMPORTANCEWhile two-component system (TCS) signaling has been investigated at depth in model strains of Escherichia coli, there have been no studies to elucidate-at a systems level-which TCSs are important during infection by pathogenic Escherichia coli. Here, we report the generation of a markerless TCS deletion library in a uropathogenic E. coli (UPEC) isolate that can be leveraged for dissecting the role of TCS signaling in different aspects of pathogenesis. We use this library to demonstrate, for the first time in UPEC, that niche-specific colonization is guided by distinct TCS groups.
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Affiliation(s)
- John R. Brannon
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Seth A. Reasoner
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Tomas A. Bermudez
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sarah L. Comer
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Michelle A. Wiebe
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Taryn L. Dunigan
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Connor J. Beebout
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Tamia Ross
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Adebisi Bamidele
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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6
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Snoeck S, Guidi C, De Mey M. "Metabolic burden" explained: stress symptoms and its related responses induced by (over)expression of (heterologous) proteins in Escherichia coli. Microb Cell Fact 2024; 23:96. [PMID: 38555441 PMCID: PMC10981312 DOI: 10.1186/s12934-024-02370-9] [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: 12/01/2023] [Accepted: 03/18/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND Engineering bacterial strains to redirect the metabolism towards the production of a specific product has enabled the development of industrial biotechnology. However, rewiring the metabolism can have severe implications for a microorganism, rendering cells with stress symptoms such as a decreased growth rate, impaired protein synthesis, genetic instability and an aberrant cell size. On an industrial scale, this is reflected in processes that are not economically viable. MAIN TEXT In literature, most stress symptoms are attributed to "metabolic burden", however the actual triggers and stress mechanisms involved are poorly understood. Therefore, in this literature review, we aimed to get a better insight in how metabolic engineering affects Escherichia coli and link the observed stress symptoms to its cause. Understanding the possible implications that chosen engineering strategies have, will help to guide the reader towards optimising the envisioned process more efficiently. CONCLUSION This review addresses the gap in literature and discusses the triggers and effects of stress mechanisms that can be activated when (over)expressing (heterologous) proteins in Escherichia coli. It uncovers that the activation of the different stress mechanisms is complex and that many are interconnected. The reader is shown that care has to be taken when (over)expressing (heterologous) proteins as the cell's metabolism is tightly regulated.
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Affiliation(s)
- Sofie Snoeck
- Department of Biotechnology, Centre for Synthetic Biology, Coupure Links 653, Gent, 9000, Belgium
| | - Chiara Guidi
- Department of Biotechnology, Centre for Synthetic Biology, Coupure Links 653, Gent, 9000, Belgium
| | - Marjan De Mey
- Department of Biotechnology, Centre for Synthetic Biology, Coupure Links 653, Gent, 9000, Belgium.
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7
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Rojas VK, Winter MG, Jimenez AG, Tanner NW, Crockett SL, Spiga L, Hendrixson DR, Winter SE. Gene regulation of infection-associated L-tartrate metabolism in Salmonella enterica serovar Typhimurium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.05.578992. [PMID: 38370731 PMCID: PMC10871181 DOI: 10.1101/2024.02.05.578992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection.
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Affiliation(s)
- Vivian K. Rojas
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
| | - Maria G. Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
| | - Angel G. Jimenez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Current address: Infectious Diseases, Genentech, South San Francisco, California, USA
| | - Natasha W. Tanner
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
| | - Stacey L. Crockett
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Luisella Spiga
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Current address: Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David R. Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sebastian E. Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
- Department of Medical Microbiology and Immunology, UC Davis School of Medicine, Davis, CA, USA
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8
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Addington E, Sandalli S, Roe AJ. Current understandings of colibactin regulation. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001427. [PMID: 38314762 PMCID: PMC10924459 DOI: 10.1099/mic.0.001427] [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: 10/30/2023] [Accepted: 01/12/2024] [Indexed: 02/07/2024]
Abstract
The biosynthetic machinery for the production of colibactin is encoded by 19 genes (clbA - S) within the pks pathogenicity island harboured by many E. coli of the B2-phylogroup. Colibactin is a potent genotoxic metabolite which causes DNA-damage and which has potential roles in microbial competition and fitness of pks+ bacteria. Colibactin has also been strongly implicated in the development of colorectal cancer. Given the genotoxicity of colibactin and the metabolic cost of its synthesis, the regulatory system governing the clb cluster is accordingly highly complex, and many of the mechanisms remain to be elucidated. In this review we summarise the current understanding of regulation of colibactin biosynthesis by internal molecular components and how these factors are modulated by signals from the external environment.
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Affiliation(s)
- Emily Addington
- School of Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Scotland, UK
| | - Sofia Sandalli
- School of Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Scotland, UK
| | - Andrew J. Roe
- School of Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Scotland, UK
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9
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Mintz KP, Danforth DR, Ruiz T. The Trimeric Autotransporter Adhesin EmaA and Infective Endocarditis. Pathogens 2024; 13:99. [PMID: 38392837 PMCID: PMC10892112 DOI: 10.3390/pathogens13020099] [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: 12/11/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Infective endocarditis (IE), a disease of the endocardial surface of the heart, is usually of bacterial origin and disproportionally affects individuals with underlying structural heart disease. Although IE is typically associated with Gram-positive bacteria, a minority of cases are caused by a group of Gram-negative species referred to as the HACEK group. These species, classically associated with the oral cavity, consist of bacteria from the genera Haemophilus (excluding Haemophilus influenzae), Aggregatibacter, Cardiobacterium, Eikenella, and Kingella. Aggregatibacter actinomycetemcomitans, a bacterium of the Pasteurellaceae family, is classically associated with Aggressive Periodontitis and is also concomitant with the chronic form of the disease. Bacterial colonization of the oral cavity serves as a reservoir for infection at distal body sites via hematological spreading. A. actinomycetemcomitans adheres to and causes disease at multiple physiologic niches using a diverse array of bacterial cell surface structures, which include both fimbrial and nonfimbrial adhesins. The nonfimbrial adhesin EmaA (extracellular matrix binding protein adhesin A), which displays sequence heterogeneity dependent on the serotype of the bacterium, has been identified as a virulence determinant in the initiation of IE. In this chapter, we will discuss the known biochemical, molecular, and structural aspects of this protein, including its interactions with extracellular matrix components and how this multifunctional adhesin may contribute to the pathogenicity of A. actinomycetemcomitans.
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Affiliation(s)
- Keith P. Mintz
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA;
| | - David R. Danforth
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA;
| | - Teresa Ruiz
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA;
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Charron R, Lemée P, Huguet A, Minlong O, Boulanger M, Houée P, Soumet C, Briandet R, Bridier A. Polyhexamethylene biguanide promotes adaptive cross-resistance to gentamicin in Escherichia coli biofilms. Front Cell Infect Microbiol 2023; 13:1324991. [PMID: 38149014 PMCID: PMC10750414 DOI: 10.3389/fcimb.2023.1324991] [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: 10/20/2023] [Accepted: 11/16/2023] [Indexed: 12/28/2023] Open
Abstract
Antimicrobial resistance is a critical public health issue that requires a thorough understanding of the factors that influence the selection and spread of antibiotic-resistant bacteria. Biocides, which are widely used in cleaning and disinfection procedures in a variety of settings, may contribute to this resistance by inducing similar defense mechanisms in bacteria against both biocides and antibiotics. However, the strategies used by bacteria to adapt and develop cross-resistance remain poorly understood, particularly within biofilms -a widespread bacterial habitat that significantly influences bacterial tolerance and adaptive strategies. Using a combination of adaptive laboratory evolution experiments, genomic and RT-qPCR analyses, and biofilm structural characterization using confocal microscopy, we investigated in this study how Escherichia coli biofilms adapted after 28 days of exposure to three biocidal active substances and the effects on cross-resistance to antibiotics. Interestingly, polyhexamethylene biguanide (PHMB) exposure led to an increase of gentamicin resistance (GenR) phenotypes in biofilms formed by most of the seven E. coli strains tested. Nevertheless, most variants that emerged under biocidal conditions did not retain the GenR phenotype after removal of antimicrobial stress, suggesting a transient adaptation (adaptive resistance). The whole genome sequencing of variants with stable GenR phenotypes revealed recurrent mutations in genes associated with cellular respiration, including cytochrome oxidase (cydA, cyoC) and ATP synthase (atpG). RT-qPCR analysis revealed an induction of gene expression associated with biofilm matrix production (especially curli synthesis), stress responses, active and passive transport and cell respiration during PHMB exposure, providing insight into potential physiological responses associated with adaptive crossresistance. In addition, confocal laser scanning microscopy (CLSM) observations demonstrated a global effect of PHMB on biofilm architectures and compositions formed by most E. coli strains, with the appearance of dense cellular clusters after a 24h-exposure. In conclusion, our results showed that the PHMB exposure stimulated the emergence of an adaptive cross-resistance to gentamicin in biofilms, likely induced through the activation of physiological responses and biofilm structural modulations altering gradients and microenvironmental conditions in the biological edifice.
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Affiliation(s)
- Raphaël Charron
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
- Université Paris-Saclay, National Research Institute for Agriculture, Food and the Environment (INRAE), AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Pierre Lemée
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
| | - Antoine Huguet
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
| | - Ornella Minlong
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
| | - Marine Boulanger
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
| | - Paméla Houée
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
| | - Christophe Soumet
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
| | - Romain Briandet
- Université Paris-Saclay, National Research Institute for Agriculture, Food and the Environment (INRAE), AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Arnaud Bridier
- Antibiotics, Biocides, Residues and Resistance Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Fougères, France
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11
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Luo X, Zhang A, Tai CH, Chen J, Majdalani N, Storz G, Gottesman S. An acetyltranferase moonlights as a regulator of the RNA binding repertoire of the RNA chaperone Hfq in Escherichia coli. Proc Natl Acad Sci U S A 2023; 120:e2311509120. [PMID: 38011569 PMCID: PMC10710024 DOI: 10.1073/pnas.2311509120] [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: 07/07/2023] [Accepted: 10/23/2023] [Indexed: 11/29/2023] Open
Abstract
Bacterial small RNAs (sRNAs) regulate gene expression by base-pairing with their target mRNAs. In Escherichia coli and many other bacteria, this process is dependent on the RNA chaperone Hfq, a mediator for sRNA-mRNA annealing. YhbS (renamed here as HqbA), a putative Gcn5-related N-acetyltransferase (GNAT), was previously identified as a silencer of sRNA signaling in a genomic library screen. Here, we studied how HqbA regulates sRNA signaling and investigated its physiological roles in modulating Hfq activity. Using fluorescent reporter assays, we found that HqbA overproduction suppressed all tested Hfq-dependent sRNA signaling. Direct interaction between HqbA and Hfq was demonstrated both in vivo and in vitro, and mutants that blocked the interaction interfered with HqbA suppression of Hfq. However, an acetylation-deficient HqbA mutant still disrupted sRNA signaling, and HqbA interacted with Hfq at a site far from the active site. This suggests that HqbA may be bifunctional, with separate roles for regulating via Hfq interaction and for acetylation of undefined substrates. Gel shift assays revealed that HqbA strongly reduced the interaction between the Hfq distal face and low-affinity RNAs but not high-affinity RNAs. Comparative RNA immunoprecipitation of Hfq and sequencing showed enrichment of two tRNA precursors, metZWV and proM, by Hfq in mutants that lost the HqbA-Hfq interaction. Our results suggest that HqbA provides a level of quality control for Hfq by competing with low-affinity RNA binders.
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Affiliation(s)
- Xing Luo
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD20892
| | - Aixia Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD20892-4417
| | - Chin-Hsien Tai
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD20892
| | - Jiandong Chen
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD20892
| | - Nadim Majdalani
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD20892
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD20892-4417
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD20892
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12
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Brown AN, Anderson MT, Smith SN, Bachman MA, Mobley HLT. Conserved metabolic regulator ArcA responds to oxygen availability, iron limitation, and cell envelope perturbations during bacteremia. mBio 2023; 14:e0144823. [PMID: 37681955 PMCID: PMC10653796 DOI: 10.1128/mbio.01448-23] [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: 07/12/2023] [Accepted: 07/17/2023] [Indexed: 09/09/2023] Open
Abstract
IMPORTANCE Infections of the bloodstream are life-threatening and can result in sepsis. Gram-negative bacteria cause a significant portion of bloodstream infections, which is also referred to as bacteremia. The long-term goal of our work is to understand how such bacteria establish and maintain infection during bacteremia. We have previously identified the transcription factor ArcA, which promotes fermentation in bacteria, as a likely contributor to the growth and survival of bacteria in this environment. Here, we study ArcA in the Gram-negative species Citrobacter freundii, Klebsiella pneumoniae, and Serratia marcescens. Our findings aid in determining how these bacteria sense their environment, utilize nutrients, and generate energy while countering the host immune system. This information is critical for developing better models of infection to inform future therapeutic development.
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Affiliation(s)
- Aric N. Brown
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Mark T. Anderson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sara N. Smith
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Michael A. Bachman
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Harry L. T. Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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13
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Lv Q, Shang Y, Bi H, Yang J, Lin L, Shi C, Wang M, Xie R, Zhu Z, Wang F, Hua L, Chen H, Wu B, Peng Z. Identification of two-component system ArcAB and the universal stress protein E in Pasteurella multocida and their effects on bacterial fitness and pathogenesis. Microbes Infect 2023:105235. [PMID: 37802468 DOI: 10.1016/j.micinf.2023.105235] [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: 08/05/2023] [Revised: 09/28/2023] [Accepted: 10/01/2023] [Indexed: 10/10/2023]
Abstract
Two-component regulatory system (TCS) is a widespread bacterial signal transduction mechanism and plays a critical role in bacterial adaptation to environments as well as regulating bacterial virulence. However, few studies have reported the actions of TCS in Pasteurella multocida, a zoonotic bacterial pathogen. In this study, genes encoding proteins homologous to the ArcAB TCS were identified in genome sequences of P. multocida belonging to different serogroups, and the transcription of both arcA and arcB was up-regulated in anaerobic and superoxygen environment. Compared to wild type strains, P. multocida arcA-deletion mutants (ΔarcA) displayed a decrease in growing under anaerobic conditions, biofilm formation, as well as the capacities of anti-serum bactericidal effect, cell adherence and invasion, anti-phagocytosis, and virulence in different in vivo models (Galleria mellonella and mice). RNA-Seq identified 70 significantly downregulated genes in ΔarcA compared to the wild type strain, and several of them are associated with P. multocida virulence. Among them, a universal stress protein E encoding gene uspE was characterized in P. multocida for the first time. Electrophoretic mobility shift assay (EMSA) demonstrated that the ArcAB TCS could regulate uspE directly. Deletion of uspE also led to a decrease of P. multocida in growing under anaerobic conditions, biofilm formation, anti-serum bactericidal effect, cell adherence and invasion, anti-phagocytosis, and virulence in mice. The data provided from this study will help further understanding the fitness and pathogenesis of P. multocida.
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Affiliation(s)
- Qingjie Lv
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yuyao Shang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Haixin Bi
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Jie Yang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Lin Lin
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Congcong Shi
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Mixue Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Rui Xie
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Zhanwei Zhu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Fei Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Lin Hua
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Bin Wu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Zhong Peng
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; Hubei Hongshan Laboratory, Wuhan, China; Frontiers Science Center for Animal Breeding and Sustainable Production, The Cooperative Innovation Central for Sustainable Pig Production, Wuhan, China.
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14
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Tomita K, Hirose A, Tanaka Y, Kouzuma A, Watanabe K. Electrogenetic control of gene expression in Shewanella oneidensis MR-1 using Arc-dependent transcriptional promoters. J Biosci Bioeng 2023:S1389-1723(23)00134-2. [PMID: 37244813 DOI: 10.1016/j.jbiosc.2023.05.001] [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: 03/24/2023] [Revised: 04/29/2023] [Accepted: 05/01/2023] [Indexed: 05/29/2023]
Abstract
Electrochemically active bacteria (EAB) are capable of electrically interacting with electrodes, enabling their application in bioelectrochemical systems (BESs). As the performance of BES is related to the metabolic activities of EAB, the development of methods to control their metabolic activities is important to facilitate BES applications. A recent study found that the EAB Shewanella oneidensis MR-1 uses the Arc system to regulate the expression of catabolic genes in response to electrode potentials, suggesting that a methodology for electrical control of gene expression in EAB, referred to as electrogenetics, can be developed by using electrode potential-responsive, Arc-dependent transcriptional promoters. Here, we explored Arc-dependent promoters in the genomes of S. oneidensis MR-1 and Escherichia coli to identify electrode potential-responsive promoters that are differentially activated in MR-1 cells exposed to high- and low-potential electrodes. LacZ reporter assays using electrode-associated cells of MR-1 derivatives revealed that the activities of promoters located upstream of the E. coli feo gene (Pfeo) and the MR-1 nqrA2 (SO_0902) gene (Pnqr2) were significantly increased when S. oneidensis cells were exposed to electrodes poised at +0.7 V and -0.4 V (versus the standard hydrogen electrode), respectively. Additionally, we developed a microscopic system for in situ monitoring of promoter activity in electrode-associated cells and found that Pnqr2 activity was persistently induced in MR-1 cells associated with an electrode poised at -0.4 V. Our results indicate that these electrode potential-responsive promoters enable efficient regulation of gene expression in EAB, providing a molecular basis for the development of electrogenetics.
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Affiliation(s)
- Keisuke Tomita
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Atsumi Hirose
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Yugo Tanaka
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
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15
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Brannon JR, Reasoner SA, Bermudez TA, Dunigan TL, Wiebe MA, Beebout CJ, Ross T, Bamidele A, Hadjifrangiskou M. Mapping Niche-specific Two-Component System Requirements in Uropathogenic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.23.541942. [PMID: 37292752 PMCID: PMC10245908 DOI: 10.1101/2023.05.23.541942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sensory systems allow pathogens to differentiate between different niches and respond to stimuli within them. A major mechanism through which bacteria sense and respond to stimuli in their surroundings is two-component systems (TCSs). TCSs allow for the detection of multiple stimuli to lead to a highly controlled and rapid change in gene expression. Here, we provide a comprehensive list of TCSs important for the pathogenesis of uropathogenic Escherichia coli (UPEC). UPEC accounts for >75% of urinary tract infections (UTIs) worldwide. UTIs are most prevalent among people assigned female at birth, with the vagina becoming colonized by UPEC in addition to the gut and the bladder. In the bladder, adherence to the urothelium triggers E. coli invasion of bladder cells and an intracellular pathogenic cascade. Intracellular E. coli are safely hidden from host neutrophils, competition from the microbiota, and antibiotics that kill extracellular E. coli. To survive in these intimately connected, yet physiologically diverse niches E. coli must rapidly coordinate metabolic and virulence systems in response to the distinct stimuli encountered in each environment. We hypothesized that specific TCSs allow UPEC to sense these diverse environments encountered during infection with built-in redundant safeguards. Here, we created a library of isogenic TCS deletion mutants that we leveraged to map distinct TCS contributions to infection. We identify - for the first time - a comprehensive panel of UPEC TCSs that are critical for infection of the genitourinary tract and report that the TCSs mediating colonization of the bladder, kidneys, or vagina are distinct.
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Affiliation(s)
- John R. Brannon
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Seth A. Reasoner
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Tomas A. Bermudez
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Taryn L. Dunigan
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michelle A. Wiebe
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Connor J. Beebout
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Tamia Ross
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Adebisi Bamidele
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Urology, Vanderbilt University Medical Center, Nashville, TN, USA
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16
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Roles of Two-Component Signal Transduction Systems in Shigella Virulence. Biomolecules 2022; 12:biom12091321. [PMID: 36139160 PMCID: PMC9496106 DOI: 10.3390/biom12091321] [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] [Received: 08/08/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
Two-component signal transduction systems (TCSs) are widespread types of protein machinery, typically consisting of a histidine kinase membrane sensor and a cytoplasmic transcriptional regulator that can sense and respond to environmental signals. TCSs are responsible for modulating genes involved in a multitude of bacterial functions, including cell division, motility, differentiation, biofilm formation, antibiotic resistance, and virulence. Pathogenic bacteria exploit the capabilities of TCSs to reprogram gene expression according to the different niches they encounter during host infection. This review focuses on the role of TCSs in regulating the virulence phenotype of Shigella, an intracellular pathogen responsible for severe human enteric syndrome. The pathogenicity of Shigella is the result of the complex action of a wide number of virulence determinants located on the chromosome and on a large virulence plasmid. In particular, we will discuss how five TCSs, EnvZ/OmpR, CpxA/CpxR, ArcB/ArcA, PhoQ/PhoP, and EvgS/EvgA, contribute to linking environmental stimuli to the expression of genes related to virulence and fitness within the host. Considering the relevance of TCSs in the expression of virulence in pathogenic bacteria, the identification of drugs that inhibit TCS function may represent a promising approach to combat bacterial infections.
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17
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Degradation of Exogenous Fatty Acids in Escherichia coli. Biomolecules 2022; 12:biom12081019. [PMID: 35892328 PMCID: PMC9329746 DOI: 10.3390/biom12081019] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/19/2022] [Accepted: 07/19/2022] [Indexed: 12/10/2022] Open
Abstract
Many bacteria possess all the machineries required to grow on fatty acids (FA) as a unique source of carbon and energy. FA degradation proceeds through the β-oxidation cycle that produces acetyl-CoA and reduced NADH and FADH cofactors. In addition to all the enzymes required for β-oxidation, FA degradation also depends on sophisticated systems for its genetic regulation and for FA transport. The fact that these machineries are conserved in bacteria suggests a crucial role in environmental conditions, especially for enterobacteria. Bacteria also possess specific enzymes required for the degradation of FAs from their environment, again showing the importance of this metabolism for bacterial adaptation. In this review, we mainly describe FA degradation in the Escherichia coli model, and along the way, we highlight and discuss important aspects of this metabolism that are still unclear. We do not detail exhaustively the diversity of the machineries found in other bacteria, but we mention them if they bring additional information or enlightenment on specific aspects.
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