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Xie ST, Zhu D, Song YQ, Zhu YG, Ding LJ. Unveiling potential roles of earthworms in mitigating the presence of virulence factor genes in terrestrial ecosystems. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:135133. [PMID: 38986408 DOI: 10.1016/j.jhazmat.2024.135133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 07/01/2024] [Accepted: 07/05/2024] [Indexed: 07/12/2024]
Abstract
Earthworms can redistribute soil microbiota, and thus might affect the profile of virulence factor genes (VFGs) which are carried by pathogens in soils. Nevertheless, the knowledge of VFG profile in the earthworm guts and its interaction with earthworm gut microbiome is still lacking. Herein, we characterized earthworm gut and soil microbiome and VFG profiles in natural and agricultural ecosystems at a national scale using metagenomics. VFG profiles in the earthworm guts significantly differed from those in the surrounding soils, which was mainly driven by variations of bacterial communities. Furthermore, the total abundance of different types of VFGs in the earthworm guts was about 20-fold lower than that in the soils due to the dramatic decline (also by approximately 20-fold) of VFG-carrying bacterial pathogens in the earthworm guts. Additionally, five VFGs related to nutritional/metabolic factors and stress survival were identified as keystones merely in the microbe-VFG network in the earthworm guts, implying their pivotal roles in facilitating pathogen colonization in earthworm gut microhabitats. These findings suggest the potential roles of earthworms in reducing risks related to the presence of VFGs in soils, providing novel insights into earthworm-based bioremediation of VFG contamination in terrestrial ecosystems.
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Affiliation(s)
- Shu-Ting Xie
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Dong Zhu
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China; Key Laboratory of Urban Environment and Health, Ningbo Urban Environment Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, China
| | - Ya-Qiong Song
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Sino-Danish College of University of Chinese Academy of Sciences, Beijing 101400, China; Sino-Danish Centre for Education and Research, Beijing 100049, China; Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
| | - Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Jimei District, Xiamen 361021, China
| | - Long-Jun Ding
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.
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Wölflingseder M, Fengler VH, Standhartinger V, Wagner GE, Reidl J. The regulatory network comprising ArcAB-RpoS-RssB influences motility in Vibrio cholerae. Mol Microbiol 2024; 121:850-864. [PMID: 38323722 DOI: 10.1111/mmi.15235] [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: 07/24/2023] [Revised: 01/08/2024] [Accepted: 01/21/2024] [Indexed: 02/08/2024]
Abstract
The diarrheal disease cholera is caused by the versatile and responsive bacterium Vibrio cholerae, which is capable of adapting to environmental changes. Among others, the alternative sigma factor RpoS activates response pathways, including regulation of motility- and chemotaxis-related genes under nutrient-poor conditions in V. cholerae. Although RpoS has been well characterised, links between RpoS and other regulatory networks remain unclear. In this study, we identified the ArcAB two-component system to control rpoS transcription and RpoS protein stability in V. cholerae. In a manner similar to that seen in Escherichia coli, the ArcB kinase not only activates the response regulator ArcA but also RssB, the anti-sigma factor of RpoS. Our results demonstrated that, in V. cholerae, RssB is phosphorylated by ArcB, which subsequently activates RpoS proteolysis. Furthermore, ArcA acts as a repressor of rpoS transcription. Additionally, we determined that the cysteine residue at position 180 of ArcB is crucial for signal recognition and activity. Thus, our findings provide evidence linking RpoS response to the anoxic redox control system ArcAB in V. cholerae.
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Affiliation(s)
- Martina Wölflingseder
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Vera H Fengler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Verena Standhartinger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Gabriel E Wagner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
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3
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Jeong GJ, Khan F, Tabassum N, Kim YM. Cellular and physiological roles of sigma factors in Vibrio spp.: A comprehensive review. Int J Biol Macromol 2024; 254:127833. [PMID: 37918595 DOI: 10.1016/j.ijbiomac.2023.127833] [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: 08/23/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023]
Abstract
Vibrio species are motile gram-negative bacteria commonly found in aquatic environments. Vibrio species include pathogenic as well as non-pathogenic strains. Pathogenic Vibrio species have been reported in invertebrates and humans, whereas non-pathogenic strains are involved in symbiotic relationships with their eukaryotic hosts. These bacteria are also able to adapt to fluctuations in temperature, salinity, and pH, in addition to oxidative stress, and osmotic pressure in aquatic ecosystems. Moreover, they have also developed protective mechanisms against the immune systems of their hosts. Vibrio species accomplish adaptation to changing environments outside or inside the host by altering their gene expression profiles. To this end, several sigma factors specifically regulate gene expression, particularly under stressful environmental conditions. Moreover, other sigma factors are associated with biofilm formation and virulence as well. This review discusses different types of sigma and anti-sigma factors of Vibrio species involved in virulence and regulation of gene expression upon changes in environmental conditions. The evolutionary relationships between sigma factors with various physiological roles in Vibrio species are also discussed extensively.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Fazlurrahman Khan
- Institute of Fisheries Sciences, Pukyong National University, Busan 48513, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan 48513, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
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4
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Gubensäk N, Sagmeister T, Buhlheller C, Geronimo BD, Wagner GE, Petrowitsch L, Gräwert MA, Rotzinger M, Berger TMI, Schäfer J, Usón I, Reidl J, Sánchez-Murcia PA, Zangger K, Pavkov-Keller T. Vibrio cholerae's ToxRS bile sensing system. eLife 2023; 12:e88721. [PMID: 37768326 PMCID: PMC10624426 DOI: 10.7554/elife.88721] [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: 04/20/2023] [Accepted: 09/27/2023] [Indexed: 09/29/2023] Open
Abstract
The seventh pandemic of the diarrheal cholera disease, which began in 1960, is caused by the Gram-negative bacterium Vibrio cholerae. Its environmental persistence provoking recurring sudden outbreaks is enabled by V. cholerae's rapid adaption to changing environments involving sensory proteins like ToxR and ToxS. Located at the inner membrane, ToxR and ToxS react to environmental stimuli like bile acid, thereby inducing survival strategies for example bile resistance and virulence regulation. The presented crystal structure of the sensory domains of ToxR and ToxS in combination with multiple bile acid interaction studies, reveals that a bile binding pocket of ToxS is only properly folded upon binding to ToxR. Our data proposes an interdependent functionality between ToxR transcriptional activity and ToxS sensory function. These findings support the previously suggested link between ToxRS and VtrAC-like co-component systems. Besides VtrAC, ToxRS is now the only experimentally determined structure within this recently defined superfamily, further emphasizing its significance. In-depth analysis of the ToxRS complex reveals its remarkable conservation across various Vibrio species, underlining the significance of conserved residues in the ToxS barrel and the more diverse ToxR sensory domain. Unravelling the intricate mechanisms governing ToxRS's environmental sensing capabilities, provides a promising tool for disruption of this vital interaction, ultimately inhibiting Vibrio's survival and virulence. Our findings hold far-reaching implications for all Vibrio strains that rely on the ToxRS system as a shared sensory cornerstone for adapting to their surroundings.
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Affiliation(s)
- Nina Gubensäk
- Institute of Molecular Biosciences, University of GrazGrazAustria
| | - Theo Sagmeister
- Institute of Molecular Biosciences, University of GrazGrazAustria
| | | | - Bruno Di Geronimo
- Laboratory of Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto-Loewi Research Center, Medical University of GrazGrazAustria
| | - Gabriel E Wagner
- Institute of Chemistry / Organic and Bioorganic Chemistry, Medical University of GrazGrazAustria
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of GrazGrazAustria
| | | | | | - Markus Rotzinger
- Institute of Chemistry / Organic and Bioorganic Chemistry, Medical University of GrazGrazAustria
| | | | | | - Isabel Usón
- Institute of Molecular Biology of BarcelonaBarcelonaSpain
- ICREA, Institució Catalana de Recerca i Estudis AvançatsBarcelonaSpain
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of GrazGrazAustria
- BioHealth Field of Excellence, University of GrazGrazAustria
- BioTechMed-GrazGrazAustria
| | - Pedro A Sánchez-Murcia
- Laboratory of Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto-Loewi Research Center, Medical University of GrazGrazAustria
| | - Klaus Zangger
- Institute of Chemistry / Organic and Bioorganic Chemistry, Medical University of GrazGrazAustria
- BioHealth Field of Excellence, University of GrazGrazAustria
- BioTechMed-GrazGrazAustria
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of GrazGrazAustria
- BioHealth Field of Excellence, University of GrazGrazAustria
- BioTechMed-GrazGrazAustria
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5
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Montero DA, Vidal RM, Velasco J, George S, Lucero Y, Gómez LA, Carreño LJ, García-Betancourt R, O’Ryan M. Vibrio cholerae, classification, pathogenesis, immune response, and trends in vaccine development. Front Med (Lausanne) 2023; 10:1155751. [PMID: 37215733 PMCID: PMC10196187 DOI: 10.3389/fmed.2023.1155751] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/14/2023] [Indexed: 05/24/2023] Open
Abstract
Vibrio cholerae is the causative agent of cholera, a highly contagious diarrheal disease affecting millions worldwide each year. Cholera is a major public health problem, primarily in countries with poor sanitary conditions and regions affected by natural disasters, where access to safe drinking water is limited. In this narrative review, we aim to summarize the current understanding of the evolution of virulence and pathogenesis of V. cholerae as well as provide an overview of the immune response against this pathogen. We highlight that V. cholerae has a remarkable ability to adapt and evolve, which is a global concern because it increases the risk of cholera outbreaks and the spread of the disease to new regions, making its control even more challenging. Furthermore, we show that this pathogen expresses several virulence factors enabling it to efficiently colonize the human intestine and cause cholera. A cumulative body of work also shows that V. cholerae infection triggers an inflammatory response that influences the development of immune memory against cholera. Lastly, we reviewed the status of licensed cholera vaccines, those undergoing clinical evaluation, and recent progress in developing next-generation vaccines. This review offers a comprehensive view of V. cholerae and identifies knowledge gaps that must be addressed to develop more effective cholera vaccines.
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Affiliation(s)
- David A. Montero
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Roberto M. Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Instituto Milenio de Inmunología e Inmunoterapia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juliana Velasco
- Unidad de Paciente Crítico, Clínica Hospital del Profesor, Santiago, Chile
- Programa de Formación de Especialista en Medicina de Urgencia, Universidad Andrés Bello, Santiago, Chile
| | - Sergio George
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Yalda Lucero
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Pediatría y Cirugía Infantil, Hospital Dr. Roberto del Rio, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Leonardo A. Gómez
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Leandro J. Carreño
- Instituto Milenio de Inmunología e Inmunoterapia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Programa de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Richard García-Betancourt
- Programa de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Miguel O’Ryan
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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6
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Dynamic Mechanism of Phase Variations in Bacteria Based on Multistable Gene Regulatory Networks. J Theor Biol 2022; 549:111212. [DOI: 10.1016/j.jtbi.2022.111212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 06/23/2022] [Accepted: 06/28/2022] [Indexed: 11/20/2022]
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7
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Controlled Proteolysis of an Essential Virulence Determinant Dictates Infectivity of Lyme Disease Pathogens. Infect Immun 2022; 90:e0005922. [PMID: 35416705 DOI: 10.1128/iai.00059-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Borrelia burgdorferi BB0323 protein undergoes a complex yet poorly defined proteolytic maturation event that generates N-terminal and C-terminal proteins with essential functions in cell growth and infection. Here, we report that a borrelial protease, B. burgdorferi high temperature requirement A protease (BbHtrA), cleaves BB0323 between asparagine (N) and leucine (L) at positions 236 and 237, while the replacement of these residues with alanine in the mutant protein prevents its cleavage, despite preserving its normal secondary structure. The N-terminal BB0323 protein binds BbHtrA, but its cleavage site mutant displays deficiency in such interaction. An isogenic borrelial mutant with NL-to-AA substitution in BB0323 (referred to as Bbbb0323NL) maintains normal growth yet is impaired for infection of mice or transmission from infected ticks. Notably, the BB0323 protein is still processed in Bbbb0323NL, albeit with lower levels of mature N-terminal BB0323 protein and multiple aberrantly processed polypeptides, which could result from nonspecific cleavages at other asparagine and leucine residues in the protein. The lack of infectivity of Bbbb0323NL is likely due to the impaired abundance or stoichiometry of a protein complex involving BB0238, another spirochete protein. Together, these studies highlight that a precise proteolytic event and a particular protein-protein interaction, involving multiple borrelial virulence determinants, are mutually inclusive and interconnected, playing essential roles in the infectivity of Lyme disease pathogens.
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8
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Kanungo S, Azman AS, Ramamurthy T, Deen J, Dutta S. Cholera. Lancet 2022; 399:1429-1440. [PMID: 35397865 DOI: 10.1016/s0140-6736(22)00330-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/14/2021] [Accepted: 02/07/2022] [Indexed: 12/11/2022]
Abstract
Cholera was first described in the areas around the Bay of Bengal and spread globally, resulting in seven pandemics during the past two centuries. It is caused by toxigenic Vibrio cholerae O1 or O139 bacteria. Cholera is characterised by mild to potentially fatal acute watery diarrhoeal disease. Prompt rehydration therapy is the cornerstone of management. We present an overview of cholera and its pathogenesis, natural history, bacteriology, and epidemiology, while highlighting advances over the past 10 years in molecular epidemiology, immunology, and vaccine development and deployment. Since 2014, the Global Task Force on Cholera Control, a WHO coordinated network of partners, has been working with several countries to develop national cholera control strategies. The global roadmap for cholera control focuses on stopping transmission in cholera hotspots through vaccination and improved water, sanitation, and hygiene, with the aim to reduce cholera deaths by 90% and eliminate local transmission in at least 20 countries by 2030.
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Affiliation(s)
- Suman Kanungo
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Andrew S Azman
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD, USA; Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | - Jaqueline Deen
- Institute of Child Health and Human Development, National Institutes of Health, University of the Philippines-Manila, Manila, Philippines
| | - Shanta Dutta
- National Institute of Cholera and Enteric Diseases, Kolkata, India.
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Kim H, Burkinshaw BJ, Lam LG, Manera K, Dong TG. Identification of Small Molecule Inhibitors of the Pathogen Box against Vibrio cholerae. Microbiol Spectr 2021; 9:e0073921. [PMID: 34937180 PMCID: PMC8694189 DOI: 10.1128/spectrum.00739-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/18/2021] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance (AMR) has become a serious public and economic threat. The rate of bacteria acquiring AMR surpasses the rate of new antibiotics discovery, projecting more deadly AMR infections in the future. The Pathogen Box is an open-source library of drug-like compounds that can be screened for antibiotic activity. We have screened molecules of the Pathogen Box against Vibrio cholerae, the cholera-causing pathogen, and successfully identified two compounds, MMV687807 and MMV675968, that inhibit growth. RNA-seq analyses of V. cholerae after incubation with each compound revealed that both compounds affect cellular functions on multiple levels including carbon metabolism, iron homeostasis, and biofilm formation. In addition, whole-genome sequencing analysis of spontaneous resistance mutants identified an efflux system that confers resistance to MMV687807. We also identified that the dihydrofolate reductase is the likely target of MMV675968 suggesting it acts as an analog of trimethoprim but with a MIC 14-fold lower than trimethoprim in molar concentration. In summary, these two compounds that effectively inhibit V. cholerae and other bacteria may lead to the development of new antibiotics for better treatment of the cholera disease. IMPORTANCE Cholera is a serious infectious disease in tropical regions causing millions of infections annually. Vibrio cholerae, the causative agent of cholera, has gained multi-antibiotic resistance over the years, posing greater threat to public health and current treatment strategies. Here we report two compounds that effectively target the growth of V. cholerae and have the potential to control cholera infection.
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Affiliation(s)
- Haeun Kim
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Brianne J. Burkinshaw
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Linh G. Lam
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kevin Manera
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Tao G. Dong
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
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10
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Gao C, Garren M, Penn K, Fernandez VI, Seymour JR, Thompson JR, Raina JB, Stocker R. Coral mucus rapidly induces chemokinesis and genome-wide transcriptional shifts toward early pathogenesis in a bacterial coral pathogen. THE ISME JOURNAL 2021; 15:3668-3682. [PMID: 34168314 PMCID: PMC8630044 DOI: 10.1038/s41396-021-01024-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/12/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023]
Abstract
Elevated seawater temperatures have contributed to the rise of coral disease mediated by bacterial pathogens, such as the globally distributed Vibrio coralliilyticus, which utilizes coral mucus as a chemical cue to locate stressed corals. However, the physiological events in the pathogens that follow their entry into the coral host environment remain unknown. Here, we present simultaneous measurements of the behavioral and transcriptional responses of V. coralliilyticus BAA-450 incubated in coral mucus. Video microscopy revealed a strong and rapid chemokinetic behavioral response by the pathogen, characterized by a two-fold increase in average swimming speed within 6 min of coral mucus exposure. RNA sequencing showed that this bacterial behavior was accompanied by an equally rapid differential expression of 53% of the genes in the V. coralliilyticus genome. Specifically, transcript abundance 10 min after mucus exposure showed upregulation of genes involved in quorum sensing, biofilm formation, and nutrient metabolism, and downregulation of flagella synthesis and chemotaxis genes. After 60 min, we observed upregulation of genes associated with virulence, including zinc metalloproteases responsible for causing coral tissue damage and algal symbiont photoinactivation, and secretion systems that may export toxins. Together, our results suggest that V. coralliilyticus employs a suite of behavioral and transcriptional responses to rapidly shift into a distinct infection mode within minutes of exposure to the coral microenvironment.
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Affiliation(s)
- Cherry Gao
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Civil and Environmental Engineering, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland
| | - Melissa Garren
- Working Ocean Strategies LLC, Carmel, CA, USA
- Department of Applied Environmental Science, California State University Monterey Bay, Seaside, CA, USA
| | - Kevin Penn
- Department of Civil and Environmental Engineering, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Vicente I Fernandez
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland
| | - Justin R Seymour
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Janelle R Thompson
- Singapore Center for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | - Jean-Baptiste Raina
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Roman Stocker
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland.
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11
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Quinn JD, Weening EH, Miller VL. PsaF Is a Membrane-Localized pH Sensor That Regulates psaA Expression in Yersinia pestis. J Bacteriol 2021; 203:e0016521. [PMID: 34060904 PMCID: PMC8407435 DOI: 10.1128/jb.00165-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/21/2021] [Indexed: 12/30/2022] Open
Abstract
The Yersinia pestis pH 6 antigen (PsaA) forms fimbria-like structures and is required for full virulence during bubonic plague. High temperature and low pH regulate PsaA production, and while recent work has uncovered the molecular aspects of temperature control, the mechanisms underlying this unusual regulation by pH are poorly understood. Using defined growth conditions, we recently showed that high levels of PsaE and PsaF (two regulatory proteins required for expression of psaA) are present at mildly acidic pH, but these levels are greatly reduced at neutral pH, resulting in low psaA expression. In prior work, the use of translational reporters suggested that pH had no impact on translation of psaE and psaF, but rather affected protein stability of PsaE and/or PsaF. Here, we investigated the pH-dependent posttranslational mechanisms predicted to regulate PsaE and PsaF stability. Using antibodies that recognize the endogenous proteins, we showed that the amount of PsaE and PsaF is defined by a distinct pH threshold. Analysis of histidine residues in the periplasmic domain of PsaF suggested that it functions as a pH sensor and indicated that the presence of PsaF is important for PsaE stability. At neutral pH, when PsaF is absent, PsaE appears to be targeted for proteolytic degradation by regulated intramembrane proteolysis. Together, our work shows that Y. pestis utilizes PsaF as a pH sensor to control psaA expression by enhancing the stability of PsaE, an essential psaA regulatory protein. IMPORTANCE Yersinia pestis is a bacterial pathogen that causes bubonic plague in humans. As Y. pestis cycles between fleas and mammals, it senses the environment within each host to appropriately control gene expression. PsaA is a protein that forms fimbria-like structures and is required for virulence. High temperature and low pH together stimulate psaA transcription by increasing the levels of two essential integral membrane regulators, PsaE and PsaF. Histidine residues in the PsaF periplasmic domain enable it to function as a pH sensor. In the absence of PsaF, PsaE (a DNA-binding protein) appears to be targeted for proteolytic degradation, thus preventing expression of psaA. This work offers insight into the mechanisms that bacteria use to sense pH and control virulence gene expression.
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Affiliation(s)
- Joshua D. Quinn
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Eric H. Weening
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Virginia L. Miller
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, USA
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12
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Yokoyama T, Niinae T, Tsumagari K, Imami K, Ishihama Y, Hizukuri Y, Akiyama Y. The Escherichia coli S2P intramembrane protease RseP regulates ferric citrate uptake by cleaving the sigma factor regulator FecR. J Biol Chem 2021; 296:100673. [PMID: 33865858 PMCID: PMC8144685 DOI: 10.1016/j.jbc.2021.100673] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/08/2021] [Accepted: 04/14/2021] [Indexed: 02/03/2023] Open
Abstract
Escherichia coli RseP, a member of the site-2 protease family of intramembrane proteases, is involved in the activation of the σE extracytoplasmic stress response and elimination of signal peptides from the cytoplasmic membrane. However, whether RseP has additional cellular functions is unclear. In this study, we used mass spectrometry-based quantitative proteomic analysis to search for new substrates that might reveal unknown physiological roles for RseP. Our data showed that the levels of several Fec system proteins encoded by the fecABCDE operon (fec operon) were significantly decreased in an RseP-deficient strain. The Fec system is responsible for the uptake of ferric citrate, and the transcription of the fec operon is controlled by FecI, an alternative sigma factor, and its regulator FecR, a single-pass transmembrane protein. Assays with a fec operon expression reporter demonstrated that the proteolytic activity of RseP is essential for the ferric citrate-dependent upregulation of the fec operon. Analysis using the FecR protein and FecR-derived model proteins showed that FecR undergoes sequential processing at the membrane and that RseP participates in the last step of this sequential processing to generate the N-terminal cytoplasmic fragment of FecR that participates in the transcription of the fec operon with FecI. A shortened FecR construct was not dependent on RseP for activation, confirming this cleavage step is the essential and sufficient role of RseP. Our study unveiled that E. coli RseP performs the intramembrane proteolysis of FecR, a novel physiological role that is essential for regulating iron uptake by the ferric citrate transport system.
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Affiliation(s)
- Tatsuhiko Yokoyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Tomoya Niinae
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kazuya Tsumagari
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Koshi Imami
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yasushi Ishihama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yohei Hizukuri
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.
| | - Yoshinori Akiyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.
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13
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Belisario JC, Lee HH, Luknauth H, Rigel NW, Martinez LR. Acinetobacter baumannii Strains Deficient in the Clp Chaperone-Protease Genes Have Reduced Virulence in a Murine Model of Pneumonia. Pathogens 2021; 10:pathogens10020204. [PMID: 33668542 PMCID: PMC7917692 DOI: 10.3390/pathogens10020204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/05/2023] Open
Abstract
Acinetobacter baumannii has emerged as a significant opportunistic Gram-negative pathogen and causative agent of nosocomial pneumonia especially in immunocompromised individuals in intensive care units. Recent advances to understand the contribution and function of A. baumannii virulence factors in its pathogenesis have begun to elucidate how this bacterium interacts with immune cells and its interesting mechanisms for multi-antibiotic resistance. Taking advantage of the availability of the A. baumannii AB5075 transposon mutant library, we investigated the impact of the A. baumannii Clp genes, which encode for a chaperone-protease responsible for the degradation of misfolded proteins, on bacterial virulence in a model of pneumonia using C57BL/6 mice and survival within J774.16 macrophage-like cells. Clp-protease A. baumannii mutants exhibit decreased virulence in rodents, high phagocytic cell-mediated killing and reduced biofilm formation. Capsular staining showed evidence of encapsulation in A. baumannii AB5075 and Clp-mutant strains. Surprisingly, clpA and clpS mutants displayed irregular cell morphology, which may be important in the biofilm structural deficiencies observed in these strains. Interestingly, clpA showed apical-like growth, proliferation normally observed in filamentous fungi. These findings provide new information regarding A. baumannii pathogenesis and may be important for the development of therapies intended at reducing morbidity and mortality associated with this remarkable pathogen.
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Affiliation(s)
- J Christian Belisario
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania, Philadelphia, PA 19146, USA;
- Department of Biomedical Sciences, NYIT College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA;
| | - Hiu Ham Lee
- Department of Biomedical Sciences, NYIT College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA;
| | - Harshani Luknauth
- Department of Biology, Hofstra University, Hempstead, NY 11549, USA; (H.L.); (N.W.R.)
| | - Nathan W. Rigel
- Department of Biology, Hofstra University, Hempstead, NY 11549, USA; (H.L.); (N.W.R.)
| | - Luis R. Martinez
- Department of Biomedical Sciences, NYIT College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA;
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL 32610, USA
- Correspondence:
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14
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Pennetzdorfer N, Höfler T, Wölflingseder M, Tutz S, Schild S, Reidl J. σ E controlled regulation of porin OmpU in Vibrio cholerae. Mol Microbiol 2021; 115:1244-1261. [PMID: 33330989 PMCID: PMC8359247 DOI: 10.1111/mmi.14669] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 01/19/2023]
Abstract
Bile resistance is essential for enteric pathogens, as exemplified by Vibrio cholerae, the causative agent of cholera. The outer membrane porin OmpU confers bacterial survival and colonization advantages in the presence of host‐derived antimicrobial peptides as well as bile. Expression of ompU is controlled by the virulence regulator ToxR. rpoE knockouts are accompanied by suppressor mutations causing ompU downregulation. Therefore, OmpU constitutes an intersection of the ToxR regulon and the σE‐pathway in V. cholerae. To understand the mechanism by which the sigma factor σE regulates OmpU synthesis, we performed transcription studies using ompU reporter fusions and immunoblot analysis. Our data revealed an increase in ompU promoter activity in ΔrpoE strains, as well as in a ΔompU background, indicating a negative feedback regulation circuit of ompU expression. This regulation seems necessary, since elevated lethality rates of ΔrpoE strains occur upon ompU overexpression. Manipulation of OmpU’s C‐terminal portion revealed its relevance for protein stability and potency of σE release. Furthermore, ΔrpoE strains are still capable of elevating OmpU levels under membrane stress conditions triggered by the bile salt sodium deoxycholate. This study provides new details about the impact of σE on ompU regulation, which is critical to the pathogen’s intestinal survival.
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Affiliation(s)
| | - Thomas Höfler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Sarah Tutz
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
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15
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Gubensäk N, Wagner GE, Schrank E, Falsone FS, Berger TMI, Pavkov-Keller T, Reidl J, Zangger K. The periplasmic domains of Vibriocholerae ToxR and ToxS are forming a strong heterodimeric complex independent on the redox state of ToxR cysteines. Mol Microbiol 2021; 115:1277-1291. [PMID: 33368680 PMCID: PMC8359183 DOI: 10.1111/mmi.14673] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 01/24/2023]
Abstract
The transmembrane protein ToxR plays a key role in the virulence expression system of Vibrio cholerae. The activity of ToxR is dependent on its periplasmic sensor domain (ToxRp) and on the inner membrane protein ToxS. Herein, we present the Nuclear Magnetic Resonance NMR solution structure of the sensory ToxRp containing an intramolecular disulfide bond. The presented structural and dynamic experiments with reduced and oxidized ToxRp propose an explanation for the increased proteolytic sensitivity of reduced ToxR. Additionally, for the first time, we could identify the formation of a strong heterodimer complex between the periplasmic domains of ToxR and ToxS in solution. NMR interaction studies reveal that binding of ToxS is not dependent on the redox state of ToxR cysteines, and formed complexes are structurally similar. By monitoring the proteolytic cleavage of ToxRp with NMR, we additionally provide a direct evidence of ToxS protective function. Taken together our results suggest that ToxR activity is regulated by its stability which is, on the one hand, dependent on the redox states of its cysteines, influencing the stability of its fold, and on the other hand, on its interaction with ToxS, which binds independent on the cysteines and acts as a protection against proteases.
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Affiliation(s)
- Nina Gubensäk
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria.,Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gabriel E Wagner
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria.,Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Evelyne Schrank
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria
| | - Fabio S Falsone
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria.,KAGes Healthcare, Graz, Austria
| | | | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
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16
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Effect of low power lasers on prokaryotic and eukaryotic cells under different stress condition: a review of the literature. Lasers Med Sci 2021; 36:1139-1150. [PMID: 33387079 DOI: 10.1007/s10103-020-03196-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022]
Abstract
Radiations emitted by low power radiation sources have been applied for therapeutic proposals due to their capacity of inactivating bacteria and cancer cells in photodynamic therapy and stimulating tissue cells in photobiomodulation. Exposure to these radiations could increase cell proliferation in bacterial cultures under stressful conditions. Cells in infected or not infected tissue injuries are also under stressful conditions and photobiomodulation-induced regenerative effect on tissue injuries could be related to effects on stressed cells. The understanding of the effects on cells under stressful conditions could render therapies based on photobiomodulation more efficient as well as expand them. Thus, the objective of this review was to update the studies reporting photobiomodulation on prokaryotic and eukaryotic cells under stress conditions. Exposure to radiations emitted by low power radiation sources could induce adaptive responses enabling cells to survive in stressful conditions, such as those experienced by bacteria in their host and by eukaryotic cells in injured tissues. Adaptive responses could be the basis for clinical photobiomodulation applications, either considering their contraindication for treatment of infected injuries or indication for treatment of injuries, inflammatory process resolution, or tissue regeneration.
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17
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Species-Specific Quorum Sensing Represses the Chitobiose Utilization Locus in Vibrio cholerae. Appl Environ Microbiol 2020; 86:AEM.00915-20. [PMID: 32651201 DOI: 10.1128/aem.00915-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/04/2020] [Indexed: 01/30/2023] Open
Abstract
The marine facultative pathogen Vibrio cholerae forms complex multicellular communities on the chitinous shells of crustacean zooplankton in its aquatic reservoir. V. cholerae-chitin interactions are critical for the growth, evolution, and waterborne transmission of cholera. This is due, in part, to chitin-induced changes in gene expression in this pathogen. Here, we sought to identify factors that influence chitin-induced expression of one locus, the chitobiose utilization operon (chb), which is required for the uptake and catabolism of the chitin disaccharide. Through a series of genetic screens, we identified that the master regulator of quorum sensing, HapR, is a direct repressor of the chb operon. We also found that the levels of HapR in V. cholerae are regulated by the ClpAP protease. Furthermore, we show that the canonical quorum sensing cascade in V. cholerae regulates chb expression in an HapR-dependent manner. Through this analysis, we found that signaling via the species-specific autoinducer CAI-1, but not the interspecies autoinducer AI-2, influences chb expression. This phenomenon of species-specific regulation may enhance the fitness of this pathogen in its environmental niche.IMPORTANCE In nature, bacteria live in multicellular and multispecies communities. Microbial species can sense the density and composition of their community through chemical cues using a process called quorum sensing (QS). The marine pathogen Vibrio cholerae is found in communities on the chitinous shells of crustaceans in its aquatic reservoir. V. cholerae interactions with chitin are critical for the survival, evolution, and waterborne transmission of this pathogen. Here, we show that V. cholerae uses QS to regulate the expression of one locus required for V. cholerae-chitin interactions.
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18
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Huang J, Chen Y, Chen J, Liu C, Zhang T, Luo S, Huang M, Min X. Exploration of the effects of a degS mutant on the growth of Vibrio cholerae and the global regulatory function of degS by RNA sequencing. PeerJ 2019; 7:e7959. [PMID: 31660280 PMCID: PMC6815195 DOI: 10.7717/peerj.7959] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 09/29/2019] [Indexed: 01/25/2023] Open
Abstract
Background DegS is a periplasmic serine protease that is considered to be the initiator of the σE stress response pathway, and this protein plays an important role in the regulation of the stress response in E. coli. However, knowledge of the biological function and global regulatory network of DegS in Vibrio cholerae remains limited. In this study, we aimed to characterize the molecular functions and further investigate the regulatory network of degS in V. cholerae. Methods A deletion mutant of degS was constructed in the V. cholerae HN375 strain. Bacterial colony morphology was observed by a plate-based growth experiment, and bacterial growth ability was observed by a growth curve experiment. High-throughput RNA sequencing (RNA-Seq) technology was used to analyze the differential transcriptomic profiles between the wild-type and degS mutant strains. Gene ontology (GO), pathway analysis and Gene-Act-network analysis were performed to explore the main functions of the differentially expressed genes. Quantitative real-time PCR (qRT-PCR) was performed to validate the reliability and accuracy of the RNA-Seq analysis. The complementation experiments were used to test the roles of degS and ropS in the small colony degS mutant phenotype. Results When degS was deleted, the degS mutant exhibited smaller colonies on various media and slower growth than the wild-type strain. A total of 423 differentially expressed genes were identified, including 187 genes that were upregulated in the degS mutant compared to the wild-type strain and 236 genes that were relatively downregulated. GO categories and pathway analysis showed that many differentially expressed genes were associated with various cellular metabolic pathways and the cell cycle. Furthermore, Gene-Act network analysis showed that many differentially expressed genes were involved in cellular metabolic pathways and bacterial chemotaxis. The cAMP-CRP-RpoS signaling pathway and the LuxPQ signal transduction system were also affected by the degS mutant. The expression patterns of nine randomly selected differentially expressed genes were consistent between the qRT-PCR and RNA-seq results. The complementation experiments showed that the small colony degS mutant phenotype could be partially restored by complementation with the pBAD24-degS or pBAD24-rpoS plasmid. Discussion These results suggest that the degS gene is important for normal growth of V. cholerae. Some of the differentially expressed genes were involved in various cellular metabolic processes and the cell cycle, which may be associated with bacterial growth. Several new degS-related regulatory networks were identified. In addition, our results suggested that the cAMP-CRP-RpoS signaling pathway may be involved in the small colony degS mutant phenotype. Overall, we believe that these transcriptomic data will serve as useful genetic resources for research on the functions of degS in V. cholerae.
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Affiliation(s)
- Jian Huang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Yuxi Chen
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Jie Chen
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Changjin Liu
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Tao Zhang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Shilu Luo
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Meirong Huang
- Department of Blood Transfusion, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Xun Min
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China
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