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Ireton K, Mortuza R, Gyanwali GC, Gianfelice A, Hussain M. Role of internalin proteins in the pathogenesis of Listeria monocytogenes. Mol Microbiol 2021; 116:1407-1419. [PMID: 34704304 DOI: 10.1111/mmi.14836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/15/2022]
Abstract
Listeria monocytogenes is a food-borne bacterium that causes gastroenteritis, meningitis, or abortion. L. monocytogenes induces its internalization (entry) into human cells and either spreads laterally in tissues or transcytoses to traverse anatomical barriers. In this review, we discuss mechanisms by which five structurally related proteins of the "internalin" family of L. monocytogenes (InlA, InlB, InlC, InlF, and InlP) interact with distinct host receptors to promote infection of human cells and/or crossing of the intestinal, blood-brain, or placental barriers. We focus on recent results demonstrating that the internalin proteins InlA, InlB, and InlC exploit exocytic pathways to stimulate transcytosis, entry, or cell-to-cell spread, respectively. We also discuss evidence that InlA-mediated transcytosis contributes to traversal of the intestinal barrier, whereas InlF promotes entry into endothelial cells to breach the blood-brain barrier. InlB also facilitates the crossing of the blood-brain barrier, but does so by extending the longevity of infected monocytes that may subsequently act as a "Trojan horse" to transfer bacteria to the brain. InlA, InlB, and InlP each contribute to fetoplacental infection by targeting syncytiotrophoblast or cytotrophoblast layers of the placenta. This work highlights the diverse functions of internalins and the complex mechanisms by which these structurally related proteins contribute to disease.
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Affiliation(s)
- Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Roman Mortuza
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | | | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Mazhar Hussain
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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2
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Unrath N, McCabe E, Macori G, Fanning S. Application of Whole Genome Sequencing to Aid in Deciphering the Persistence Potential of Listeria monocytogenes in Food Production Environments. Microorganisms 2021; 9:1856. [PMID: 34576750 PMCID: PMC8464834 DOI: 10.3390/microorganisms9091856] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/26/2023] Open
Abstract
Listeria monocytogenes is the etiological agent of listeriosis, a foodborne illness associated with high hospitalizations and mortality rates. This bacterium can persist in food associated environments for years with isolates being increasingly linked to outbreaks. This review presents a discussion of genomes of Listeria monocytogenes which are commonly regarded as persisters within food production environments, as well as genes which are involved in mechanisms aiding this phenotype. Although criteria for the detection of persistence remain undefined, the advent of whole genome sequencing (WGS) and the development of bioinformatic tools have revolutionized the ability to find closely related strains. These advancements will facilitate the identification of mechanisms responsible for persistence among indistinguishable genomes. In turn, this will lead to improved assessments of the importance of biofilm formation, adaptation to stressful conditions and tolerance to sterilizers in relation to the persistence of this bacterium, all of which have been previously associated with this phenotype. Despite much research being published around the topic of persistence, more insights are required to further elucidate the nature of true persistence and its implications for public health.
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Affiliation(s)
- Natalia Unrath
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
| | - Evonne McCabe
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
- Department of Microbiology, St. Vincent’s University Hospital, D04 T6F4 Dublin, Ireland
| | - Guerrino Macori
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
| | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
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3
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Pombinho R, Vieira A, Camejo A, Archambaud C, Cossart P, Sousa S, Cabanes D. Virulence gene repression promotes Listeria monocytogenes systemic infection. Gut Microbes 2020; 11:868-881. [PMID: 31955655 PMCID: PMC7524345 DOI: 10.1080/19490976.2020.1712983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The capacity of bacterial pathogens to infect their hosts depends on the tight spatiotemporal regulation of virulence genes. The Listeria monocytogenes (Lm) metal efflux pump repressor CadC is highly expressed during late infection stages, modulating lipoprotein processing and host immune response. Here we investigate the potential of CadC as broad repressor of virulence genes. We show that CadC represses the expression of the bile salt hydrolase impairing Lm resistance to bile. During late infection, in absence of CadC-dependent repression, the constitutive bile salt hydrolase expression induces the overexpression of the cholic acid efflux pump MdrT that is unfavorable to Lm virulence. We establish the CadC regulon and show that CadC represses additional virulence factors activated by σB during colonization of the intestinal lumen. CadC is thus a general repressor that promotes Lm virulence by down-regulating, at late infection stages, genes required for survival in the gastrointestinal tract. This demonstrates for the first time how bacterial pathogens can repurpose regulators to spatiotemporally repress virulence genes and optimize their infectious capacity.
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Affiliation(s)
- Rita Pombinho
- Instituto de Investigação e Inovação em Saúde – i3S, Universidade do Porto, Porto, Portugal,Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular - IBMC, Porto, Portugal
| | - Ana Vieira
- Instituto de Investigação e Inovação em Saúde – i3S, Universidade do Porto, Porto, Portugal,Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular - IBMC, Porto, Portugal
| | - Ana Camejo
- Instituto de Investigação e Inovação em Saúde – i3S, Universidade do Porto, Porto, Portugal,Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular - IBMC, Porto, Portugal
| | - Cristel Archambaud
- Unité des Interactions Bactéries-Cellules, INSERM U604 and INRA USC2020, Institut Pasteur, Paris, France
| | - Pascale Cossart
- Unité des Interactions Bactéries-Cellules, INSERM U604 and INRA USC2020, Institut Pasteur, Paris, France
| | - Sandra Sousa
- Instituto de Investigação e Inovação em Saúde – i3S, Universidade do Porto, Porto, Portugal,Cell Biology of Bacterial Infections, Instituto de Biologia Molecular e Celular - IBMC, Porto, Portugal
| | - Didier Cabanes
- Instituto de Investigação e Inovação em Saúde – i3S, Universidade do Porto, Porto, Portugal,Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular - IBMC, Porto, Portugal,CONTACT Didier Cabanes i3S - Instituto de Investigação e Inovação em Saúde, IBMC - Instituto de Biologia Molecular e Celular, Group of Molecular Microbiology, Rua do Campo Rua Alfredo Allen, 2084200-135Porto, Portugal
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4
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Response of the Biocontrol Agent Pseudomonas pseudoalcaligenes AVO110 to Rosellinia necatrix Exudate. Appl Environ Microbiol 2019; 85:AEM.01741-18. [PMID: 30478234 PMCID: PMC6344628 DOI: 10.1128/aem.01741-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/17/2018] [Indexed: 01/08/2023] Open
Abstract
Diseases associated with fungal root invasion cause a significant loss of fruit tree production worldwide. The bacterium Pseudomonas pseudoalcaligenes AVO110 controls avocado white root rot disease caused by Rosellinia necatrix by using mechanisms involving competition for nutrients and niches. Here, a functional genomics approach was conducted to identify the bacterial traits involved in the interaction with this fungal pathogen. Our results contribute to a better understanding of the multitrophic interactions established among bacterial biocontrol agents, the plant rhizosphere, and the mycelia of soilborne pathogens. The rhizobacterium Pseudomonas pseudoalcaligenes AVO110, isolated by the enrichment of competitive avocado root tip colonizers, controls avocado white root rot disease caused by Rosellinia necatrix. Here, we applied signature-tagged mutagenesis (STM) during the growth and survival of AVO110 in fungal exudate-containing medium with the goal of identifying the molecular mechanisms linked to the interaction of this bacterium with R. necatrix. A total of 26 STM mutants outcompeted by the parental strain in fungal exudate, but not in rich medium, were selected and named growth-attenuated mutants (GAMs). Twenty-one genes were identified as being required for this bacterial-fungal interaction, including membrane transporters, transcriptional regulators, and genes related to the metabolism of hydrocarbons, amino acids, fatty acids, and aromatic compounds. The bacterial traits identified here that are involved in the colonization of fungal hyphae include proteins involved in membrane maintenance (a dynamin-like protein and ColS) or cyclic-di-GMP signaling and chemotaxis. In addition, genes encoding a DNA helicase (recB) and a regulator of alginate production (algQ) were identified as being required for efficient colonization of the avocado rhizosphere. IMPORTANCE Diseases associated with fungal root invasion cause a significant loss of fruit tree production worldwide. The bacterium Pseudomonas pseudoalcaligenes AVO110 controls avocado white root rot disease caused by Rosellinia necatrix by using mechanisms involving competition for nutrients and niches. Here, a functional genomics approach was conducted to identify the bacterial traits involved in the interaction with this fungal pathogen. Our results contribute to a better understanding of the multitrophic interactions established among bacterial biocontrol agents, the plant rhizosphere, and the mycelia of soilborne pathogens.
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Paul O, Chakravarty D, Donaldson JR. Transposon Mutagenesis of Listeria monocytogenes. Methods Mol Biol 2019; 2016:63-71. [PMID: 31197709 PMCID: PMC10687897 DOI: 10.1007/978-1-4939-9570-7_6] [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] [Indexed: 12/02/2023]
Abstract
Listeria monocytogenes is a Gram-positive, facultative intracellular foodborne pathogen that enters the human digestive tract after the consumption of contaminated food. Much research has been done to understand the virulence factors of Listeria monocytogenes. One useful tool to study these virulence factors has been transposon mutagenesis. Many mutants can be generated at a time by performing high-throughput mutagenesis using transposons and later screening these mutants to identify features related to particular functions in the bacteria. Many transposon delivery systems are not ideal for transposon studies in Listeria monocytogenes, as the transposon system is too large, has lower transposition efficiency, and a high rate of plasmid retention. Therefore, a new mariner-based transposition system has been developed for Listeria monocytogenes. This system is an ideal high-throughput transposon mutagenesis as the rate of transposition is high and random, along with very low plasmid retention capacity.
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Affiliation(s)
- Oindrila Paul
- Department of Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Damayanti Chakravarty
- Department of Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Janet R Donaldson
- Department of Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, MS, USA.
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Schardt J, Jones G, Müller-Herbst S, Schauer K, D'Orazio SEF, Fuchs TM. Comparison between Listeria sensu stricto and Listeria sensu lato strains identifies novel determinants involved in infection. Sci Rep 2017; 7:17821. [PMID: 29259308 PMCID: PMC5736727 DOI: 10.1038/s41598-017-17570-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/28/2017] [Indexed: 01/01/2023] Open
Abstract
The human pathogen L. monocytogenes and the animal pathogen L. ivanovii, together with four other species isolated from symptom-free animals, form the “Listeria sensu stricto” clade. The members of the second clade, “Listeria sensu lato”, are believed to be solely environmental bacteria without the ability to colonize mammalian hosts. To identify novel determinants that contribute to infection by L. monocytogenes, the causative agent of the foodborne disease listeriosis, we performed a genome comparison of the two clades and found 151 candidate genes that are conserved in the Listeria sensu stricto species. Two factors were investigated further in vitro and in vivo. A mutant lacking an ATP-binding cassette transporter exhibited defective adhesion and invasion of human Caco-2 cells. Using a mouse model of foodborne L. monocytogenes infection, a reduced number of the mutant strain compared to the parental strain was observed in the small intestine and the liver. Another mutant with a defective 1,2-propanediol degradation pathway showed reduced persistence in the stool of infected mice, suggesting a role of 1,2-propanediol as a carbon and energy source of listeriae during infection. These findings reveal the relevance of novel factors for the colonization process of L. monocytogenes.
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Affiliation(s)
- Jakob Schardt
- ZIEL-Institute for Food & Health, and Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Grant Jones
- Department of Microbiology, Immunology, & Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Stefanie Müller-Herbst
- ZIEL-Institute for Food & Health, and Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Kristina Schauer
- Lehrstuhl für Hygiene und Technologie der Milch, Tiermedizinische Fakultät, Ludwig-Maximilians-Universität München, Schönleutner Str. 8, 85764, Oberschleißheim, Germany
| | - Sarah E F D'Orazio
- Department of Microbiology, Immunology, & Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Thilo M Fuchs
- ZIEL-Institute for Food & Health, and Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany. .,Friedrich-Loeffler-Institut, Institut für Molekulare Pathogenese, Naumburger Str. 96a, 07743, Jena, Germany.
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Liu Y, Yoo BB, Hwang CA, Suo Y, Sheen S, Khosravi P, Huang L. LMOf2365_0442 Encoding for a Fructose Specific PTS Permease IIA May Be Required for Virulence in L. monocytogenes Strain F2365. Front Microbiol 2017; 8:1611. [PMID: 28900418 PMCID: PMC5581801 DOI: 10.3389/fmicb.2017.01611] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/07/2017] [Indexed: 02/06/2023] Open
Abstract
Listeria monocytogenes is a foodborne pathogen that causes listeriosis, which is a major public health concern due to the high fatality rate. LMOf2365_0442, 0443, and 0444 encode for fructose-specific EIIABC components of phosphotransferase transport system (PTS) permease that is responsible for sugar transport. In previous studies, in-frame deletion mutants of a putative fructose-specific PTS permease (LMOf2365_0442, 0443, and 0444) were constructed and analyzed. However, the virulence potential of these deletion mutants has not been studied. In this study, two in vitro methods were used to analyze the virulence potential of these L. monocytogenes deletion mutants. First, invasion assays were used to measure the invasion efficiencies to host cells using the human HT-29 cell line. Second, plaque forming assays were used to measure cell-to-cell spread in host cells. Our results showed that the deletion mutant ΔLMOf2365_0442 had reduced invasion and cell-to-cell spread efficiencies in human cell line compared to the parental strain LMOf2365, indicating that LMOf2365_0442 encoding for a fructose specific PTS permease IIA may be required for virulence in L. monocytogenes strain F2365. In addition, the gene expression levels of 15 virulence and stress-related genes were analyzed in the stationary phase cells of the deletion mutants using RT-PCR assays. Virulence-related gene expression levels were elevated in the deletion mutants ΔLMOf2365_0442-0444 compared to the wild type parental strain LMOf2365, indicating the down-regulation of virulence genes by this PTS permease in L. monocytogenes. Finally, stress-related gene clpC expression levels were also increased in all of the deletion mutants, suggesting the involvement of this PTS permease in stress response. Furthermore, these deletion mutants displayed the same pressure tolerance and the same capacity for biofilm formation compared to the wild-type parental strain LMOf2365. In summary, our findings suggest that the LMOf2365_0442 gene can be used as a potential target to develop inhibitors for new therapeutic and pathogen control strategies for public health.
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Affiliation(s)
- Yanhong Liu
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, WyndmoorPA, United States
| | - Brian B Yoo
- Clinical and Environmental Microbiology Branch, Division of Healthcare Quality and Promotion, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, AtlantaGA, United States
| | - Cheng-An Hwang
- Residue Chemistry and Predictive Microbiology Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, WyndmoorPA, United States
| | - Yujuan Suo
- Institute for Agri-Food Standards and Testing Technology, Shanghai Academy of Agricultural SciencesShanghai, China
| | - Shiowshuh Sheen
- Food Safety Intervention Technologies Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, WyndmoorPA, United States
| | - Parvaneh Khosravi
- Food Safety Intervention Technologies Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, WyndmoorPA, United States
| | - Lihan Huang
- Residue Chemistry and Predictive Microbiology Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, WyndmoorPA, United States
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Fox EM, Allnutt T, Bradbury MI, Fanning S, Chandry PS. Comparative Genomics of the Listeria monocytogenes ST204 Subgroup. Front Microbiol 2016; 7:2057. [PMID: 28066377 PMCID: PMC5177744 DOI: 10.3389/fmicb.2016.02057] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 12/07/2016] [Indexed: 11/18/2022] Open
Abstract
The ST204 subgroup of Listeria monocytogenes is among the most frequently isolated in Australia from a range of environmental niches. In this study we provide a comparative genomics analysis of food and food environment isolates from geographically diverse sources. Analysis of the ST204 genomes showed a highly conserved core genome with the majority of variation seen in mobile genetic elements such as plasmids, transposons and phage insertions. Most strains (13/15) harbored plasmids, which although varying in size contained highly conserved sequences. Interestingly 4 isolates contained a conserved plasmid of 91,396 bp. The strains examined were isolated over a period of 12 years and from different geographic locations suggesting plasmids are an important component of the genetic repertoire of this subgroup and may provide a range of stress tolerance mechanisms. In addition to this 4 phage insertion sites and 2 transposons were identified among isolates, including a novel transposon. These genetic elements were highly conserved across isolates that harbored them, and also contained a range of genetic markers linked to stress tolerance and virulence. The maintenance of conserved mobile genetic elements in the ST204 population suggests these elements may contribute to the diverse range of niches colonized by ST204 isolates. Environmental stress selection may contribute to maintaining these genetic features, which in turn may be co-selecting for virulence markers relevant to clinical infection with ST204 isolates.
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Affiliation(s)
- Edward M Fox
- CSIRO Food and Nutrition Werribee, VIC, Australia
| | | | | | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin Dublin, Ireland
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Choby JE, Skaar EP. Heme Synthesis and Acquisition in Bacterial Pathogens. J Mol Biol 2016; 428:3408-28. [PMID: 27019298 PMCID: PMC5125930 DOI: 10.1016/j.jmb.2016.03.018] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis.
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Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN, USA.
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10
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Zhang T, Bae D, Wang C. LMOh7858_0369, a gene encoding a putative leucine-rich repeat-containing protein, is required for virulence of Listeria monocytogenes. FEMS Microbiol Lett 2016; 363:fnw060. [PMID: 26976852 DOI: 10.1093/femsle/fnw060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2016] [Indexed: 11/13/2022] Open
Abstract
Listeria monocytogenes possesses the highest number of leucine-rich repeat (LRR)-containing proteins among all Gram-positive bacteria; these LRR-containing molecules are known as the 'internalin' family. To understand the functions of largely uncharacterized LRR-containing molecules, we constructed seven deletion mutants in the L. monocytogenes H7858 strain targeting genes in this family and tested their virulence. Among the seven mutants, the ΔLMOh7858_0369 strain and the ΔLMOh7858_2546 strain showed significantly impaired invasiveness of HepG2 cells. We further tested the virulence of these two strains in the intravascular sepsis model using BALB/c mice. Interestingly, the ΔLMOh7858_0369 strain showed significant reduction in organ colonization, bacteremia and invasion of the brain compared with the parental wild-type strain. Host immune responses to listerial intravascular infection were measured at 24 and 72 h post-infection. Transcript levels of several proinflammatory cytokines and chemokines were significantly lower when induced by the ΔlmOh7858_0369 strain than when induced by the wild type. These results suggest that the putative LRR-containing protein encoded by LMOh7858_0369 might be a novel virulence factor of the L. monocytogenes H7858 strain.
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Affiliation(s)
- Ting Zhang
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Dongryeoul Bae
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Chinling Wang
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
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11
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Scornec H, Tichit M, Bouchier C, Pédron T, Cavin JF, Sansonetti PJ, Licandro-Seraut H. Rapid 96-well plates DNA extraction and sequencing procedures to identify genome-wide transposon insertion sites in a difficult to lyse bacterium: Lactobacillus casei. J Microbiol Methods 2014; 106:78-82. [PMID: 25135488 DOI: 10.1016/j.mimet.2014.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/04/2014] [Accepted: 08/05/2014] [Indexed: 11/18/2022]
Abstract
Random transposon mutagenesis followed by adequate screening methods is an unavoidable procedure to characterize genetics of bacterial adaptation to environmental changes. We have recently constructed a mutant library of Lactobacillus casei and we aimed to fully annotate it. However, we have observed that, for L. casei which is a difficult to lyse bacterium, methods used to identify the transposon insertion site in a few mutants (transposon rescue by restriction and recircularization or PCR-based methods) were not transposable for a larger number because they are too time-consuming and sometimes not reliable. Here, we describe a method for large-scale and reliable identification of transposon insertion sites in a L. casei mutant library of 9250 mutants. DNA extraction procedure based on silica membranes in 96-column format was optimized to obtain genomic DNA from a large number of mutants. Then reliable direct genomic sequencing was improved to fit the obtained genomic DNA extracts. Using this procedure, readable and identifiable sequences were obtained for 87% of the L. casei mutants. This method extends the applications of a library of this type, reduces the number of insertions needed to be screened, and allows selection of specific mutants from an arrayed and stored mutant library. This method is applicable to any already existing mutant library (obtained by transposon or insertional mutagenesis) and could be useful for other bacterial species, especially for highly lysis-resistant bacteria species such as lactic acid bacteria.
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Affiliation(s)
- Hélène Scornec
- UMR A PAM, AgroSup Dijon/Université de Bourgogne, 1 Esplanade Erasme, 21000, Dijon, France
| | - Magali Tichit
- Plate-forme Génomique, Département Génomes et Génétique, Institut Pasteur, 28 Rue du Docteur Roux, 75724, Paris cedex 15, France
| | - Christiane Bouchier
- Plate-forme Génomique, Département Génomes et Génétique, Institut Pasteur, 28 Rue du Docteur Roux, 75724, Paris cedex 15, France
| | - Thierry Pédron
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 28 Rue du Docteur Roux, 75724, Paris cedex 15, France; Unité INSERM 786, Institut Pasteur, Paris, France
| | - Jean-François Cavin
- UMR A PAM, AgroSup Dijon/Université de Bourgogne, 1 Esplanade Erasme, 21000, Dijon, France
| | - Philippe J Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 28 Rue du Docteur Roux, 75724, Paris cedex 15, France; Unité INSERM 786, Institut Pasteur, Paris, France; Chaire de Microbiologie et Maladies Infectieuses, Collège de France, 11 Place Marcelin Berthelot, 75005, Paris, France.
| | - Hélène Licandro-Seraut
- UMR A PAM, AgroSup Dijon/Université de Bourgogne, 1 Esplanade Erasme, 21000, Dijon, France; Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 28 Rue du Docteur Roux, 75724, Paris cedex 15, France
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12
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Gahan CGM, Hill C. Listeria monocytogenes: survival and adaptation in the gastrointestinal tract. Front Cell Infect Microbiol 2014; 4:9. [PMID: 24551601 PMCID: PMC3913888 DOI: 10.3389/fcimb.2014.00009] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 01/18/2014] [Indexed: 12/27/2022] Open
Abstract
The foodborne pathogen Listeria monocytogenes has the capacity to survive and grow in a diverse range of natural environments. The transition from a food environment to the gastrointestinal tract begins a process of adaptation that may culminate in invasive systemic disease. Here we describe recent advances in our understanding of how L. monocytogenes adapts to the gastrointestinal environment prior to initiating systemic infection. We will discuss mechanisms used by the pathogen to survive encounters with acidic environments (which include the glutamate decarboxylase and arginine deiminase systems), and those which enable the organism to cope with bile acids (including bile salt hydrolase) and competition with the resident microbiota. An increased understanding of how the pathogen survives in this environment is likely to inform the future design of novel prophylactic approaches that exploit specific pharmabiotics; including probiotics, prebiotics, or phages.
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Affiliation(s)
- Cormac G M Gahan
- Alimentary Pharmabiotic Centre, University College Cork Cork, Ireland ; School of Microbiology, University College Cork Cork, Ireland ; School of Pharmacy, University College Cork Cork, Ireland
| | - Colin Hill
- Alimentary Pharmabiotic Centre, University College Cork Cork, Ireland ; School of Microbiology, University College Cork Cork, Ireland
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