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Bartula K, Biagui S, Begley M, Callanan M. Investigation of the growth of Listeria in plant-based beverages. Food Microbiol 2024; 121:104530. [PMID: 38637090 DOI: 10.1016/j.fm.2024.104530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/16/2024] [Accepted: 03/29/2024] [Indexed: 04/20/2024]
Abstract
The objective of the present study was to evaluate whether the content of sugar, protein, fat, or fibre in commercially available and specially formulated plant-based beverages (oat, soya and pea) influences the growth rates of Listeria. Beverages were inoculated with a strain cocktail of Listeria (approximately 1 × 103 CFU/mL), and the data demonstrated that Listeria could proliferate in all tested beverages. Moreover, varying concentrations of naturally occurring or added sugar (0-3.3%), protein (3.3-5%), fat (1.1-3.5%) and added fibre (0-1.5%) did not have a statistically significant (p > 0.05) impact on the growth rates of Listeria in the tested plant-based beverages. These data suggest that the wide variety of commercial plant-based beverages serve as an ideal medium for the growth of Listeria irrespective of product composition. All the various products tested provided sufficient nutrients to support at least a 2.6-log increase of Listeria within 16 h at room temperature, with some beverages supporting a 3-log increase. Therefore, these data highlight the importance of careful storage and handling of these increasingly varied and popular products.
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Affiliation(s)
- Klaudia Bartula
- Department of Biological Sciences, Munster Technological University, Bishopstown, Cork, Ireland.
| | - Sambou Biagui
- Department of Biological Sciences, Munster Technological University, Bishopstown, Cork, Ireland.
| | - Máire Begley
- Department of Biological Sciences, Munster Technological University, Bishopstown, Cork, Ireland.
| | - Michael Callanan
- Department of Biological Sciences, Munster Technological University, Bishopstown, Cork, Ireland.
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2
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Fante N, Desiderato CK, Riedel CU, Grünberger A. Time-resolved cell-to-cell heterogeneity of Listeria innocua after nisin exposure. Front Bioeng Biotechnol 2024; 12:1408652. [PMID: 38933537 PMCID: PMC11199691 DOI: 10.3389/fbioe.2024.1408652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/13/2024] [Indexed: 06/28/2024] Open
Abstract
The use of bacteriocins is a promising approach for addressing the immense threat of food-borne and drug-resistant pathogens. In recent years screening platforms for novel bacteriocins using whole-cell biosensors have been established. During screening cell-to-cell heterogeneity is currently neglected but might play a crucial role in signal development of the whole-cell biosensor after bacteriocin exposure. In this study, we explored the temporal dynamics of the signal heterogeneity of the biosensor Listeria innocua LMG2785/pNZpHin2 Lm after nisin exposure using microfluidic single-cell analysis. The results provided novel and detailed insights into the dynamics of cell-to-cell heterogeneity in L. innocua LMG2785/pNZpHin2 Lm at different nisin concentrations with a high spatio-temporal resolution. Furthermore, the formation of subpopulations during bacteriocin exposure was observed. In-depth single-cell tracking even revealed the regeneration of disrupted cells and recovery of pH homeostasis in rare instances. These findings are highly important for the future design and execution of bacteriocin assays and for the interpretation of fluorescence signal development at the population level after exposure to different concentrations of bacteriocins (here, nisin), as well as for obtaining deeper insights into single-cell persistence strategies to quantify the efficacy and efficiency of novel bacteriocins.
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Affiliation(s)
- Niklas Fante
- Multiscale Bioengineering, Technical Faculty, Bielefeld University, Bielefeld, Germany
| | | | | | - Alexander Grünberger
- Multiscale Bioengineering, Technical Faculty, Bielefeld University, Bielefeld, Germany
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
- Institute of Process Engineering in Life Sciences: Microsystems in Bioprocess Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
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3
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Chatterjee A, Kaval KG, Garsin DA. Role of ethanolamine utilization and bacterial microcompartment formation in Listeria monocytogenes intracellular infection. Infect Immun 2024; 92:e0016224. [PMID: 38752742 PMCID: PMC11237587 DOI: 10.1128/iai.00162-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 04/18/2024] [Indexed: 05/28/2024] Open
Abstract
Ethanolamine (EA) affects the colonization and pathogenicity of certain human bacterial pathogens in the gastrointestinal tract. However, EA can also affect the intracellular survival and replication of host cell invasive bacteria such as Listeria monocytogenes (LMO) and Salmonella enterica serovar Typhimurium (S. Typhimurium). The EA utilization (eut) genes can be categorized as regulatory, enzymatic, or structural, and previous work in LMO showed that loss of genes encoding functions for the enzymatic breakdown of EA inhibited LMO intracellular replication. In this work, we sought to further characterize the role of EA utilization during LMO infection of host cells. Unlike what was previously observed for S. Typhimurium, in LMO, an EA regulator mutant (ΔeutV) was equally deficient in intracellular replication compared to an EA metabolism mutant (ΔeutB), and this was consistent across Caco-2, RAW 264.7, and THP-1 cell lines. The structural genes encode proteins that self-assemble into bacterial microcompartments (BMCs) that encase the enzymes necessary for EA metabolism. For the first time, native EUT BMCs were fluorescently tagged, and EUT BMC formation was observed in vitro and in vivo. Interestingly, BMC formation was observed in bacteria infecting Caco-2 cells, but not the macrophage cell lines. Finally, the cellular immune response of Caco-2 cells to infection with eut mutants was examined, and it was discovered that ΔeutB and ΔeutV mutants similarly elevated the expression of inflammatory cytokines. In conclusion, EA sensing and utilization during LMO intracellular infection are important for optimal LMO replication and immune evasion but are not always concomitant with BMC formation.IMPORTANCEListeria monocytogenes (LMO) is a bacterial pathogen that can cause severe disease in immunocompromised individuals when consumed in contaminated food. It can replicate inside of mammalian cells, escaping detection by the immune system. Therefore, understanding the features of this human pathogen that contribute to its infectiousness and intracellular lifestyle is important. In this work we demonstrate that genes encoding both regulators and enzymes of EA metabolism are important for optimal growth inside mammalian cells. Moreover, the formation of specialized compartments to enable EA metabolism were visualized by tagging with a fluorescent protein and found to form when LMO infects some mammalian cell types, but not others. Interestingly, the formation of the compartments was associated with features consistent with an early stage of the intracellular infection. By characterizing bacterial metabolic pathways that contribute to survival in host environments, we hope to positively impact knowledge and facilitate new treatment strategies.
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Affiliation(s)
- Ayan Chatterjee
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, USA
| | - Karan Gautam Kaval
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, USA
| | - Danielle A Garsin
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, USA
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4
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Chatterjee A, Kaval KG, Garsin DA. Role of Ethanolamine Utilization and Bacterial Microcompartment Formation in Listeria monocytogenes Intracellular Infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.19.572424. [PMID: 38187703 PMCID: PMC10769209 DOI: 10.1101/2023.12.19.572424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Ethanolamine (EA) affects the colonization and pathogenicity of certain human bacterial pathogens in the gastrointestinal tract. However, EA can also affect the intracellular survival and replication of host-cell invasive bacteria such as Listeria monocytogenes (LMO) and Salmonella enterica serovar Typhimurium ( S. Typhimurium). The EA utilization ( eut) genes can be categorized as regulatory, enzymatic, or structural, and previous work in LMO showed that loss of genes encoding functions for the enzymatic breakdown of EA inhibited LMO intracellular replication. In this work, we sought to further characterize the role of EA utilization during LMO infection of host cells. Unlike what was previously observed for S. Typhimurium, in LMO, an EA regulator mutant ( ΔeutV) was equally deficient in intracellular replication compared to an EA metabolism mutant ( ΔeutB ), and this was consistent across Caco-2, RAW 264.7 and THP-1 cell lines. The structural genes encode proteins that self-assemble into bacterial microcompartments (BMCs) that encase the enzymes necessary for EA metabolism. For the first time, native EUT BMCs were fluorescently tagged, and EUT BMC formation was observed in vitro, and in vivo. Interestingly, BMC formation was observed in bacteria infecting Caco-2 cells, but not the macrophage cell lines. Finally, the cellular immune response of Caco-2 cells to infection with eut mutants was examined, and it was discovered that ΔeutB and ΔeutV mutants similarly elevated the expression of inflammatory cytokines. In conclusion, EA sensing and utilization during LMO intracellular infection are important for optimal LMO replication and immune evasion but are not always concomitant with BMC formation.
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5
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Berude JC, Kennouche P, Reniere ML, Portnoy DA. Listeria monocytogenes utilizes glutathione and limited inorganic sulfur compounds as sources of essential cysteine. Infect Immun 2024; 92:e0042223. [PMID: 38289071 PMCID: PMC10929415 DOI: 10.1128/iai.00422-23] [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: 10/13/2023] [Accepted: 12/13/2023] [Indexed: 02/13/2024] Open
Abstract
Listeria monocytogenes (Lm) is a Gram-positive facultative intracellular pathogen that leads a biphasic lifecycle, transitioning its metabolism and selectively inducing virulence genes when it encounters mammalian hosts. Virulence gene expression is controlled by the master virulence regulator PrfA, which is allosterically activated by the host- and bacterially derived glutathione (GSH). The amino acid cysteine is the rate-limiting substrate for GSH synthesis in bacteria and is essential for bacterial growth. Unlike many bacteria, Lm is auxotrophic for cysteine and must import exogenous cysteine for growth and virulence. GSH is enriched in the host cytoplasm, and previous work suggests that Lm utilizes exogenous GSH for PrfA activation. Despite these observations, the import mechanism(s) for GSH remains elusive. Analysis of known GSH importers predicted a homologous importer in Lm comprised of the Ctp ABC transporter and the OppDF ATPases of the Opp oligopeptide importer. Here, we demonstrated that the Ctp complex is a high-affinity GSH/GSSG importer that is required for Lm growth at physiologically relevant concentrations. Furthermore, we demonstrated that OppDF is required for GSH/GSSG import in an Opp-independent manner. These data support a model where Ctp and OppDF form a unique complex for GSH/GSSG import that supports growth and pathogenesis. In addition, we show that Lm utilizes the inorganic sulfur sources thiosulfate and H2S for growth in a CysK-dependent manner in the absence of other cysteine sources. These findings suggest a pathoadaptive role for partial cysteine auxotrophy in Lm, where locally high GSH/GSSG or inorganic sulfur concentrations may signal arrival to distinct host niches.
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Affiliation(s)
- John C. Berude
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Paul Kennouche
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Michelle L. Reniere
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
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6
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Zeng Z, Wijnands LM, Boeren S, Smid EJ, Notebaart RA, Abee T. Impact of vitamin B 12 on rhamnose metabolism, stress defense and in-vitro virulence of Listeria monocytogenes. Int J Food Microbiol 2024; 410:110486. [PMID: 37992553 DOI: 10.1016/j.ijfoodmicro.2023.110486] [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: 02/03/2023] [Revised: 07/05/2023] [Accepted: 11/11/2023] [Indexed: 11/24/2023]
Abstract
Listeria monocytogenes is a facultative anaerobe which can cause a severe food-borne infection known as listeriosis. L. monocytogenes is capable of utilizing various nutrient sources including rhamnose, a naturally occurring deoxy sugar abundant in foods. L. monocytogenes can degrade rhamnose into lactate, acetate and 1,2-propanediol. Our previous study showed that addition of vitamin B12 stimulated anaerobic growth of L. monocytogenes on rhamnose due to the activation of bacterial microcompartments for 1,2-propanediol utilization (pdu BMC) with concomitant production of propionate and propanol. Notably, anaerobic 1,2-propanediol metabolism has been linked to virulence of enteric pathogens including Salmonella spp. and L. monocytogenes. In this study we investigated the impact of B12 and BMC activation on i) aerobic and anerobic growth of L. monocytogenes on rhamnose and ii) the level of virulence. We observed B12-induced pdu BMC activation and growth stimulation only in anaerobically grown cells. Comparative Caco-2 virulence assays showed that these pdu BMC-induced cells have significantly higher translocation efficiency compared to non-induced cells (anaerobic growth without B12; aerobic growth with or without B12), while adhesion and invasion capacity is similar for all cells. Comparative proteome analysis showed specific and overlapping responses linked to metabolic shifts, activation of stress defense proteins and virulence factors, with RNA polymerase sigma factor SigL, teichoic acid export ATP-binding protein TagH, DNA repair and protection proteins, RadA and DPS, and glutathione synthase GshAB, previously linked to activation of virulence response in L. monocytogenes, uniquely upregulated in anaerobically rhamnose grown pdu-induced cells. Our results shed light on possible effects of B12 on L. monocytogenes competitive fitness and virulence activation when utilizing rhamnose in anaerobic conditions encountered during transmission and the human intestine.
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Affiliation(s)
- Zhe Zeng
- Food Microbiology, Wageningen University and Research, Wageningen, the Netherlands
| | - Lucas M Wijnands
- National Institute of Public Health and the Environment, Bilthoven, the Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, the Netherlands
| | - Eddy J Smid
- Food Microbiology, Wageningen University and Research, Wageningen, the Netherlands
| | - Richard A Notebaart
- Food Microbiology, Wageningen University and Research, Wageningen, the Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University and Research, Wageningen, the Netherlands.
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7
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Meireles D, Pombinho R, Cabanes D. Signals behind Listeria monocytogenes virulence mechanisms. Gut Microbes 2024; 16:2369564. [PMID: 38979800 PMCID: PMC11236296 DOI: 10.1080/19490976.2024.2369564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/13/2024] [Indexed: 07/10/2024] Open
Abstract
The tight and coordinated regulation of virulence gene expression is crucial to ensure the survival and persistence of bacterial pathogens in different contexts within their hosts. Considering this, bacteria do not express virulence factors homogenously in time and space, either due to their associated fitness cost or to their detrimental effect at specific infection stages. To efficiently infect and persist into their hosts, bacteria have thus to monitor environmental cues or chemical cell-to-cell signaling mechanisms that allow their transition from the external environment to the host, and therefore adjust gene expression levels, intrinsic biological activities, and appropriate behaviors. Listeria monocytogenes (Lm), a major Gram-positive facultative intracellular pathogen, stands out for its adaptability and capacity to thrive in a wide range of environments. Because of that, Lm presents itself as a significant concern in food safety and public health, that can lead to potentially life-threatening infections in humans. A deeper understanding of the intricate bacterial virulence mechanisms and the signals that control them provide valuable insights into the dynamic interplay between Lm and the host. Therefore, this review addresses the role of some crucial signals behind Lm pathogenic virulence mechanisms and explores how the ability to assimilate and interpret these signals is fundamental for pathogenesis, identifying potential targets for innovative antimicrobial strategies.
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Affiliation(s)
- Diana Meireles
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar – ICBAS, Porto, Portugal
| | - Rita Pombinho
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
| | - Didier Cabanes
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
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8
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Bannenberg JW, Boeren S, Zwietering MH, Abee T, den Besten HMW. Insight in lag phase of Listeria monocytogenes during enrichment through proteomic and transcriptomic responses. Food Res Int 2024; 175:113609. [PMID: 38128973 DOI: 10.1016/j.foodres.2023.113609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
The dynamics of the enrichment-based detection procedure of the foodborne pathogen Listeria monocytogenes from food still remains poorly understood. This enrichment is crucial in the reliable detection of this pathogen and more insight into the recovery mechanism during this step is important to advance our understanding of lag phase behaviour during enrichment. In this study we combined transcriptomic and proteomic analyses to better understand the physiological processes within the lag phase of L. monocytogenes during enrichment. Upon transfer of BHI-cultured stationary phase L. monocytogenes cells to half-Fraser enrichment broth (HFB), motility-associated genes and proteins were downregulated, while expression of metal uptake transporters, resuscitation-promoting factors that stimulate growth from dormancy, antibiotic efflux pumps and oxidative stress proteins were upregulated. Next to this, when cells with a heat stress history were cultured in enrichment broth, proteins necessary for recovery were upregulated with functions in DNA-damage repair, protein refolding, cell-wall repair, and zinc transport. Proteomic results pointed to possible factors that support shortening the lag duration, including the addition of 10 µM zinc and the addition of spent HFB containing presumed concentrations of resuscitation-promoting factors. However, these interventions did not lead to biologically relevant reduction of lag phase. Also, when cells were enriched in spent HFB, final cell concentrations were similar to enrichments in fresh HFB, indicating that the enrichment broth seems not to lack critical substrates. Concludingly, this study gives insight into the proteomic changes in the lag phase during enrichment and shows that supplementation of HFB is not the best strategy to optimize the current enrichment method.
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Affiliation(s)
- Jasper W Bannenberg
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, The Netherlands
| | - Marcel H Zwietering
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Tjakko Abee
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Heidy M W den Besten
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
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Schulz LM, Konrath A, Rismondo J. Characterisation of the growth behaviour of Listeria monocytogenes in Listeria synthetic media. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:669-683. [PMID: 37864319 PMCID: PMC10667646 DOI: 10.1111/1758-2229.13183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 06/05/2023] [Indexed: 10/22/2023]
Abstract
The foodborne pathogen Listeria monocytogenes can grow in a wide range of environmental conditions. For the study of the physiology of this organism, several chemically defined media have been developed over the past decades. Here, we examined the ability of L. monocytogenes wildtype strains EGD-e and 10403S to grow under salt and pH stress in Listeria synthetic medium (LSM). Furthermore, we determined that a wide range of carbon sources could support the growth of both wildtype strains in LSM. However, for hexose phosphate sugars such as glucose-1-phosphate, both L. monocytogenes strains need to be pre-grown under conditions, where the major virulence regulator PrfA is active. In addition, growth of both L. monocytogenes strains was observed when LSM was supplemented with the amino acid sugar N-acetylmannosamine (ManNAc). We were able to show that some of the proteins encoded in the operon lmo2795-nanE, such as the ManNAc-6-phosphate epimerase NanE, are required for growth in the presence of ManNAc. The first gene of the operon, lmo2795, encodes a transcriptional regulator of the RpiR family. Using electrophoretic mobility shift assays and quantitative real-time PCR analysis, we were able to show that Lmo2795 binds to the promoter region of the operon lmo2795-nanE and activates its expression.
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Affiliation(s)
- Lisa Maria Schulz
- Department of General Microbiology, Institute of Microbiology and GeneticsGZMB, Georg‐August University GöttingenGöttingenGermany
| | - Alicia Konrath
- Department of General Microbiology, Institute of Microbiology and GeneticsGZMB, Georg‐August University GöttingenGöttingenGermany
| | - Jeanine Rismondo
- Department of General Microbiology, Institute of Microbiology and GeneticsGZMB, Georg‐August University GöttingenGöttingenGermany
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10
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Feng Y, Chang SK, Portnoy DA. The major role of Listeria monocytogenes folic acid metabolism during infection is the generation of N-formylmethionine. mBio 2023; 14:e0107423. [PMID: 37695058 PMCID: PMC10653936 DOI: 10.1128/mbio.01074-23] [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: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 09/12/2023] Open
Abstract
IMPORTANCE Folic acid is an essential vitamin for bacteria, plants, and animals. The lack of folic acid leads to various consequences such as a shortage of amino acids and nucleotides that are fundamental building blocks for life. Though antifolate drugs are widely used for antimicrobial treatments, the underlying mechanism of bacterial folate deficiency during infection is unclear. This study compares the requirements of different folic acid end-products during the infection of Listeria monocytogenes, a facultative intracellular pathogen of animals and humans. The results reveal the critical importance of N-formylmethionine, the amino acid used by bacteria to initiate protein synthesis. This work extends the current understanding of folic acid metabolism in pathogens and potentially provides new insights into antifolate drug development in the future.
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Affiliation(s)
- Ying Feng
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Shannon K. Chang
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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11
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Elbakush AM, Fulano AM, Gomelsky M. Lignan-containing maple products inhibit Listeria monocytogenes biofilms on fresh produce. Front Microbiol 2023; 14:1258394. [PMID: 37928682 PMCID: PMC10620520 DOI: 10.3389/fmicb.2023.1258394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/05/2023] [Indexed: 11/07/2023] Open
Abstract
Major listeriosis outbreaks have been associated with fresh produce contaminated with Listeria monocytogenes. Strains that synthesize the Pss exopolysaccharide (EPS) have an estimated 102 to 104-fold advantage over nonsynthesizing strains in causing listeriosis. They more readily attach to the surfaces of fruit and vegetables forming EPS-biofilms that better withstand stresses associated with produce storage and consumption. Here, we show that the threat to fresh produce safety posed by the listerial EPS-biofilms may be countered by broadly available maple products. We serendipitously discovered that aqueous extracts of wood from several Acer (maple) and Carya (pecan, hickory) species inhibit the formation of listerial EPS-biofilms without affecting bacterial viability. One active ingredient in maple wood was identified as nortrachelogenin-8'-O-β-D-glucopyranoside (NTG). At 120 μM, this lignan decreased colonization of the EPS-synthesizing L. monocytogenes on cantaloupe pieces by approximately 150-fold, and on cut celery and lettuce by 10 to 11-fold. Another lignan, lariciresinol, which is abundant in a common food sweetener, maple syrup, had antibiofilm activity comparable to that of NTG. Diluted in the range of 1:200 to 1:800 maple syrup from two random manufacturers prevented formation of listeiral EPS-biofilms. Importantly, not only did maple products drastically decrease colonization of fresh produce by the EPS-synthesizing strains, they also decreased, by 6 to 30-fold, colonization by the L. monocytogenes strains that do not synthesize measurable EPS, including strains from the infamous 2011 cantaloupe listeriosis outbreak. Inhibition of surface colonization by various listerial strains, broad availability of maple sap and syrup as well as maple lumber processing waste position maple products as potential antibiofilm agents for protecting fresh produce from L. monocytogenes.
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Affiliation(s)
- Ahmed M. Elbakush
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
- Faculty of Veterinary Medicine, University of Tripoli, Tripoli, Libya
| | - Alex M. Fulano
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
| | - Mark Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
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12
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Berude JC, Kennouche P, Reniere ML, Portnoy DA. Listeria monocytogenes utilizes glutathione and limited inorganic sulfur compounds as a source of essential L-cysteine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562582. [PMID: 37905006 PMCID: PMC10614801 DOI: 10.1101/2023.10.16.562582] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Listeria monocytogenes ( Lm ) is a Gram-positive facultative intracellular pathogen that leads a biphasic lifecycle, transitioning its metabolism and selectively inducing virulence genes when it encounters mammalian hosts. Virulence gene expression is controlled by the master virulence regulator PrfA, which is allosterically activated by host- and bacterially-derived glutathione (GSH). The amino acid L-cysteine is the rate-limiting substrate for GSH synthesis in bacteria and is essential for bacterial growth. Unlike many bacteria, Lm is auxotrophic for L-cysteine and must import exogenous cysteine for growth and virulence. GSH is enriched in the host cytoplasm, and previous work suggests that Lm utilizes exogenous GSH for PrfA activation. Despite these observations, the import mechanism(s) for GSH remains elusive. Analysis of known GSH importers predicted a homologous importer in Lm comprised of the Ctp ABC transporter and the OppDF ATPases of the Opp oligopeptide importer. Here, we demonstrated that the Ctp complex is a high-affinity GSH/GSSG importer that is required for Lm growth at physiologically relevant concentrations. Further, we demonstrated that OppDF are required for GSH/GSSG import in an Opp-independent manner. These data support a model where Ctp and OppDF form a unique complex for GSH/GSSG import that supports growth and pathogenesis. Additionally, we show that Lm utilizes the inorganic sulfur sources thiosulfate and H 2 S for growth in a CysK-dependent manner in the absence of other L-cysteine sources. These findings suggest a pathoadaptive role for partial cysteine auxotrophy in Lm , where locally high GSH/GSSG or inorganic sulfur concentrations may signal arrival to distinct host niches.
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13
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Vaval Taylor DM, Xayarath B, Freitag NE. Two Permeases Associated with the Multifunctional CtaP Cysteine Transport System in Listeria monocytogenes Play Distinct Roles in Pathogenesis. Microbiol Spectr 2023; 11:e0331722. [PMID: 37199604 PMCID: PMC10269559 DOI: 10.1128/spectrum.03317-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 04/05/2023] [Indexed: 05/19/2023] Open
Abstract
The soil-dwelling bacterium Listeria monocytogenes survives a multitude of conditions when residing in the outside environment and as a pathogen within host cells. Key to survival within the infected mammalian host is the expression of bacterial gene products necessary for nutrient acquisition. Similar to many bacteria, L. monocytogenes uses peptide import to acquire amino acids. Peptide transport systems play an important role in nutrient uptake as well as in additional functions that include bacterial quorum sensing and signal transduction, recycling of peptidoglycan fragments, adherence to eukaryotic cells, and alterations in antibiotic susceptibility. It has been previously described that CtaP, encoded by lmo0135, is a multifunctional protein associated with activities that include cysteine transport, resistance to acid, membrane integrity, and bacterial adherence to host cells. ctaP is located next to two genes predicted to encode membrane-bound permeases lmo0136 and lmo0137, termed CtpP1 and CtpP2, respectively. Here, we show that CtpP1 and CtpP2 are required for bacterial growth in the presence of low concentrations of cysteine and for virulence in mouse infection models. Taken together, the data identify distinct nonoverlapping roles for two related permeases that are important for the growth and survival of L. monocytogenes within host cells. IMPORTANCE Bacterial peptide transport systems are important for nutrient uptake and may additionally function in a variety of other roles, including bacterial communication, signal transduction, and bacterial adherence to eukaryotic cells. Peptide transport systems often consist of a substrate-binding protein associated with a membrane-spanning permease. The environmental bacterial pathogen Listeria monocytogenes uses the substrate-binding protein CtaP not only for cysteine transport but also for resistance to acid, maintenance of membrane integrity, and bacterial adherence to host cells. In this study, we demonstrate complementary yet distinct functional roles for two membrane permeases, CtpP1 and CtpP2, that are encoded by genes linked to ctaP and that contribute to bacterial growth, invasion, and pathogenicity.
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Affiliation(s)
- Diandra M. Vaval Taylor
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Bobbi Xayarath
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Nancy E. Freitag
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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14
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Wu J, McAuliffe O, O'Byrne CP. Trehalose transport occurs via TreB in Listeria monocytogenes and it influences biofilm development and acid resistance. Int J Food Microbiol 2023; 394:110165. [PMID: 36933360 DOI: 10.1016/j.ijfoodmicro.2023.110165] [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: 12/25/2022] [Revised: 02/09/2023] [Accepted: 02/28/2023] [Indexed: 03/12/2023]
Abstract
Listeria monocytogenes is a pathogenic bacterium that can inhabit a diverse range of environmental niches. This is largely attributed to the high proportion of carbohydrate-specific phosphotransferase system (PTS) genes in its genome. Carbohydrates can be assimilated as sources of energy but additionally they can serve as niche-specific cues for L. monocytogenes to shape its global gene expression, in order to cope with anticipated stresses. To examine carbon source utilization among wild L. monocytogenes isolates and to understand underlying molecular mechanisms, a diverse collection of L. monocytogenes strains (n = 168) with whole genome sequence (WGS) data available was screened for the ability to grow in chemically defined media with different carbon sources. The majority of the strains grew in glucose, mannose, fructose, cellobiose, glycerol, trehalose, and sucrose. Maltose, lactose, and rhamnose supported slower growth while ribose did not support any growth. In contrast to other strains, strain1386, which belonged to clonal complex 5 (CC5), was unable to grow on trehalose as a sole carbon source. WGS data revealed that it carried a substitution (N352K) in a putative PTS EIIBC trehalose transporter, TreB, while this asparagine residue is conserved in other strains in this collection. Spontaneous mutants of strain 1386 that could grow in trehalose were found to harbour a reversion of the substitution in TreB. These results provide genetic evidence that TreB is responsible for trehalose uptake and that the N352 residue is essential for TreB activity. Moreover, reversion mutants also restored other unusual phenotypes that strain 1386 displayed, i.e. altered colony morphology, impaired biofilm development, and reduced acid resistance. Transcriptional analysis at stationary phase with buffered BHI media revealed that trehalose metabolism positively influences the transcription of genes encoding amino acid-based acid resistance mechanisms. In summary, our results demonstrated that N352 is key to the function of the sole trehalose transporter TreB in L. monocytogenes and suggest that trehalose metabolism alters physiology to favour biofilm development and acid stress resistance. Moreover, since strain 1386 is among the strains recommended by the European Union Reference Laboratory for conducting food challenge studies in order to determine whether or not L. monocytogenes can grow in food, these findings have important implications for food safety.
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Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland
| | | | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland.
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15
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Fulano AM, Elbakush AM, Chen LH, Gomelsky M. The Listeria monocytogenes exopolysaccharide significantly enhances colonization and survival on fresh produce. Front Microbiol 2023; 14:1126940. [PMID: 37180237 PMCID: PMC10172500 DOI: 10.3389/fmicb.2023.1126940] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 04/11/2023] [Indexed: 05/16/2023] Open
Abstract
Fresh produce contaminated with Listeria monocytogenes has caused major listeriosis outbreaks in the last decades. Our knowledge about components of the listerial biofilms formed on fresh produce and their roles in causing foodborne illness remains incomplete. Here, we investigated, for the first time, the role of the listerial Pss exopolysaccharide (EPS) in plant surface colonization and stress tolerance. Pss is the main component of L. monocytogenes biofilms synthesized at elevated levels of the second messenger c-di-GMP. We developed a new biofilm model, whereby L. monocytogenes EGD-e and its derivatives are grown in the liquid minimal medium in the presence of pieces of wood or fresh produce. After 48-h incubation, the numbers of colony forming units of the Pss-synthesizing strain on pieces of wood, cantaloupe, celery and mixed salads were 2-12-fold higher, compared to the wild-type strain. Colonization of manmade materials, metals and plastics, was largely unaffected by the presence of Pss. The biofilms formed by the EPS-synthesizing strain on cantaloupe rind were 6-16-fold more tolerant of desiccation, which resembles conditions of whole cantaloupe storage and transportation. Further, listeria in the EPS-biofilms survived exposure to low pH, a condition encountered by bacteria on the contaminated produce during passage through the stomach, by 11-116-fold better than the wild-type strain. We surmise that L. monocytogenes strains synthesizing Pss EPS have an enormous, 102-104-fold, advantage over the non-synthesizing strains in colonizing fresh produce, surviving during storage and reaching small intestines of consumers where they may cause disease. The magnitude of the EPS effect calls for better understanding of factors inducing Pss synthesis and suggests that prevention of listerial EPS-biofilms may significantly enhance fresh produce safety.
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Affiliation(s)
- Alex M. Fulano
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
| | | | - Li-Hong Chen
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
| | - Mark Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
- *Correspondence: Mark Gomelsky,
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16
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Fischer MA, Engelgeh T, Rothe P, Fuchs S, Thürmer A, Halbedel S. Listeria monocytogenes genes supporting growth under standard laboratory cultivation conditions and during macrophage infection. Genome Res 2022; 32:1711-1726. [PMID: 36114002 PMCID: PMC9528990 DOI: 10.1101/gr.276747.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/04/2022] [Indexed: 11/24/2022]
Abstract
The Gram-positive bacterium Listeria monocytogenes occurs widespread in the environment and infects humans when ingested along with contaminated food. Such infections are particularly dangerous for risk group patients, for whom they represent a life-threatening disease. To invent novel strategies to control contamination and disease, it is important to identify those cellular processes that maintain pathogen growth inside and outside the host. Here, we have applied transposon insertion sequencing (Tn-Seq) to L. monocytogenes for the identification of such processes on a genome-wide scale. Our approach identified 394 open reading frames that are required for growth under standard laboratory conditions and 42 further genes, which become necessary during intracellular growth in macrophages. Most of these genes encode components of the translation machinery and act in chromosome-related processes, cell division, and biosynthesis of the cellular envelope. Several cofactor biosynthesis pathways and 29 genes with unknown functions are also required for growth, suggesting novel options for the development of antilisterial drugs. Among the genes specifically required during intracellular growth are known virulence factors, genes compensating intracellular auxotrophies, and several cell division genes. Our experiments also highlight the importance of PASTA kinase signaling for general viability and of glycine metabolism and chromosome segregation for efficient intracellular growth of L. monocytogenes.
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Affiliation(s)
- Martin A Fischer
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| | - Tim Engelgeh
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| | - Patricia Rothe
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| | - Stephan Fuchs
- MF1 Bioinformatic Support, Robert Koch Institute, 13353 Berlin, Germany
| | - Andrea Thürmer
- MF2 Genome Sequencing, Robert Koch Institute, 13353 Berlin, Germany
| | - Sven Halbedel
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
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17
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Listeria monocytogenes TcyKLMN Cystine/Cysteine Transporter Facilitates Glutathione Synthesis and Virulence Gene Expression. mBio 2022; 13:e0044822. [PMID: 35435705 PMCID: PMC9239247 DOI: 10.1128/mbio.00448-22] [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] [Indexed: 11/20/2022] Open
Abstract
Bacterial pathogens sense the repertoire of metabolites in the mammalian niche and use this information to shift into the pathogenic state to accomplish a successful infection. Glutathione is a virulence-activating signal that is synthesized by
L. monocytogenes
during infection of mammalian cells.
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18
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Gu G, Kroft B, Lichtenwald M, Luo Y, Millner P, Patel J, Nou X. Dynamics of Listeria monocytogenes and the microbiome on fresh-cut cantaloupe and romaine lettuce during storage at refrigerated and abusive temperatures. Int J Food Microbiol 2022; 364:109531. [PMID: 35033975 DOI: 10.1016/j.ijfoodmicro.2022.109531] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/09/2021] [Accepted: 01/03/2022] [Indexed: 12/25/2022]
Abstract
Listeria monocytogenes (Lm) outbreaks and recalls associated with fresh produce in recent years have heightened concerns and demands from industry and consumers to more effectively mitigate the contamination risk of this foodborne pathogen on fresh produce. In this study, the growth of Lm and indigenous bacteria on fresh-cut cantaloupe and romaine lettuce held at refrigerated (4 °C) and abusive (10-24 °C) temperatures was determined by both culture dependent and independent methods. Composition and dynamics of bacterial communities on Lm inoculated and non-inoculated samples were analyzed by 16S rRNA high-throughput sequencing. Fresh-cut cantaloupe provided favorable growth conditions for Lm proliferation (1.7 and >6 log increase at refrigerated and abusive temperatures, respectively) to overtake indigenous bacteria. The Lm population also increased on fresh-cut lettuce, but the growth rate was lower than that of the total mesophilic bacteria, resulting in 0.4 and >2 log increase at refrigerated and abusive temperatures. Microbial diversity of fresh-cut cantaloupe was significantly lower than that of fresh-cut romaine lettuce. The Shannon index of microbial communities on cantaloupe declined after storage, but it was not significantly changed on lettuce samples. Shifts in the bacterial microbiome on cantaloupe were mainly affected by Lm inoculation, while both inoculation and storage temperature played significant roles on lettuce bacterial communities. Multiple indigenous bacteria, including Leuconostoc and Weissella spp., were negatively correlated to Lm abundance on romaine lettuce, and were determined by bioassay as potential anti-listerial species. Data derived from this study contribute to better understanding of the relationship between Lm and indigenous microbiota on fresh-cut produce during storage.
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Affiliation(s)
- Ganyu Gu
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, MD 20705, USA
| | - Brenda Kroft
- Centre for Food Safety and Security Systems, University of Maryland, College Park, MD 20742, USA
| | - Marina Lichtenwald
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, MD 20705, USA
| | - Yaguang Luo
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, MD 20705, USA
| | - Patricia Millner
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, MD 20705, USA
| | - Jitendra Patel
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, MD 20705, USA
| | - Xiangwu Nou
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, MD 20705, USA.
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19
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Wong CH, Mak IEK, Li D. Bilayer edible coating with stabilized Lactobacillus plantarum 299v improved the shelf life and safety quality of fresh-cut apple slices. Food Packag Shelf Life 2021. [DOI: 10.1016/j.fpsl.2021.100746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Bacterial Microcompartments Coupled with Extracellular Electron Transfer Drive the Anaerobic Utilization of Ethanolamine in Listeria monocytogenes. mSystems 2021; 6:6/2/e01349-20. [PMID: 33850044 PMCID: PMC8547011 DOI: 10.1128/msystems.01349-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Ethanolamine (EA) is a valuable microbial carbon and nitrogen source derived from cell membranes. EA catabolism is suggested to occur in a cellular metabolic subsystem called a bacterial microcompartment (BMC), and the activation of EA utilization (eut) genes is linked to bacterial pathogenesis. Despite reports showing that the activation of eut is regulated by a vitamin B12-binding riboswitch and that upregulation of eut genes occurs in mice, it remains unknown whether EA catabolism is BMC dependent in Listeria monocytogenes Here, we provide evidence for BMC-dependent anaerobic EA utilization via metabolic analysis, proteomics, and electron microscopy. First, we show vitamin B12-induced activation of the eut operon in L. monocytogenes coupled to the utilization of EA, thereby enabling growth. Next, we demonstrate BMC formation connected with EA catabolism with the production of acetate and ethanol in a molar ratio of 2:1. Flux via the ATP-generating acetate branch causes an apparent redox imbalance due to the reduced regeneration of NAD+ in the ethanol branch resulting in a surplus of NADH. We hypothesize that the redox imbalance is compensated by linking eut BMCs to anaerobic flavin-based extracellular electron transfer (EET). Using L. monocytogenes wild-type, BMC mutant, and EET mutant strains, we demonstrate an interaction between BMCs and EET and provide evidence for a role of Fe3+ as an electron acceptor. Taken together, our results suggest an important role of BMC-dependent EA catabolism in L. monocytogenes growth in anaerobic environments like the human gastrointestinal tract, with a crucial role for the flavin-based EET system in redox balancing.IMPORTANCE Listeria monocytogenes is a foodborne pathogen causing severe illness, and as such, it is crucial to understand the molecular mechanisms contributing to pathogenicity. One carbon source that allows L. monocytogenes to grow in humans is ethanolamine (EA), which is derived from phospholipids present in eukaryotic cell membranes. It is hypothesized that EA utilization occurs in bacterial microcompartments (BMCs), self-assembling subcellular proteinaceous structures and analogs of eukaryotic organelles. Here, we demonstrate that BMC-driven utilization of EA in L. monocytogenes results in increased energy production essential for anaerobic growth. However, exploiting BMCs and the encapsulated metabolic pathways also requires the balancing of oxidative and reductive pathways. We now provide evidence that L. monocytogenes copes with this by linking BMC activity to flavin-based extracellular electron transfer (EET) using iron as an electron acceptor. Our results shed new light on an important molecular mechanism that enables L. monocytogenes to grow using host-derived phospholipid degradation products.
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21
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Wang D, Greenwood P, Klein MS. A protein-free chemically defined medium for the cultivation of various micro-organisms with food safety significance. J Appl Microbiol 2021; 131:844-854. [PMID: 33449387 DOI: 10.1111/jam.15005] [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: 08/16/2020] [Revised: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 11/30/2022]
Abstract
AIMS To develop a broadly applicable medium free of proteins with well-defined and reproducible chemical composition for the cultivation of various micro-organisms with food safety significance. METHODS AND RESULTS The defined medium was designed as a buffered minimal salt medium supplemented with amino acids, vitamins, trace metals and other nutrients. Various strains commonly used for food safety research were selected to test the new defined medium. We investigated single growth factors needed by different strains and the growth performance of each strain cultivated in the defined medium. Results showed that the tested strains initially grew slower in the defined medium compared to tryptic soy broth, but after an overnight incubation cultures from the defined medium reached adequately high cell densities. CONCLUSIONS The newly designed defined medium can be widely applied in food safety studies that require media with well-defined chemical constituents. SIGNIFICANCE AND IMPACT OF THE STUDY Defined media are important in studies of microbial metabolites and physiological properties. A defined medium capable of cultivating different strains simultaneously is needed in the food safety area. The new defined medium has broader applications in comparing different strains directly and provides more reproducible results.
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Affiliation(s)
- D Wang
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA
| | - P Greenwood
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA
| | - M S Klein
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA
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22
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Köppel R, Tolido I, Ledermann R, Peier M. Use of a real-time thermocycler for charting bacterial growth. Eur Food Res Technol 2020. [DOI: 10.1007/s00217-020-03558-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Role of GlnR in Controlling Expression of Nitrogen Metabolism Genes in Listeria monocytogenes. J Bacteriol 2020; 202:JB.00209-20. [PMID: 32690554 DOI: 10.1128/jb.00209-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/10/2020] [Indexed: 01/27/2023] Open
Abstract
Listeria monocytogenes is a fastidious bacterial pathogen that can utilize only a limited number of nitrogen sources for growth. Both glutamine and ammonium are common nitrogen sources used in listerial defined growth media, but little is known about the regulation of their uptake or utilization. The functional role of L. monocytogenes GlnR, the transcriptional regulator of nitrogen metabolism genes in low-G+C Gram-positive bacteria, was determined using transcriptome sequencing and real-time reverse transcription-PCR experiments. The GlnR regulon included transcriptional units involved in ammonium transport (amtB glnK) and biosynthesis of glutamine (glnRA) and glutamate (gdhA) from ammonium. As in other bacteria, GlnR proved to be an autoregulatory repressor of the glnRA operon. Unexpectedly, GlnR was most active during growth with ammonium as the nitrogen source and less active in the glutamine medium, apparently because listerial cells perceive growth with glutamine as a nitrogen-limiting condition. Therefore, paradoxically, expression of the glnA gene, encoding glutamine synthetase, was highest in the glutamine medium. For the amtB glnK operon, GlnR served as both a negative regulator in the presence of ammonium and a positive regulator in the glutamine medium. The gdhA gene was subject to a third mode of regulation that apparently required an elevated level of GlnR for repression. Finally, activity of glutamate dehydrogenase encoded by the gdhA gene appeared to correlate inversely with expression of gltAB, the operon that encodes the other major glutamate-synthesizing enzyme, glutamate synthase. Both gdhA and amtB were also regulated, in a negative manner, by the global transcriptional regulator CodY.IMPORTANCE L. monocytogenes is a widespread foodborne pathogen. Nitrogen-containing compounds, such as the glutamate-containing tripeptide, glutathione, and glutamine, have been shown to be important for expression of L. monocytogenes virulence genes. In this work, we showed that a transcriptional regulator, GlnR, controls expression of critical listerial genes of nitrogen metabolism that are involved in ammonium uptake and biosynthesis of glutamine and glutamate. A different mode of GlnR-mediated regulation was found for each of these three pathways.
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Azinheiro S, Carvalho J, Prado M, Garrido-Maestu A. Multiplex Detection of Salmonella spp., E. coli O157 and L. monocytogenes by qPCR Melt Curve Analysis in Spiked Infant Formula. Microorganisms 2020; 8:E1359. [PMID: 32899815 PMCID: PMC7564587 DOI: 10.3390/microorganisms8091359] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 01/23/2023] Open
Abstract
Food poisoning continue to be a threat in the food industry showing a need to improve the detection of the pathogen responsible for the hospitalization cases and death. DNA-based techniques represent a real advantage and allow the detection of several targets at the same time, reducing cost and time of analysis. The development of new methodology using SYBR Green qPCR for the detection of L. monocytogenes, Salmonella spp. and E. coli O157 simultaneously was developed and a non-competitive internal amplification control (NC-IAC) was implemented to detect reaction inhibition. The formulation and supplementation of the enrichment medium was also optimized to allow the growth of all pathogens. The limit of detection (LoD) 95% obtained was <1 CFU/25 g for E. coli O157, and 2 CFU/25 g for Salmonella spp. and L. monocytogenes and regarding the multiplex detection a LoD 95% of 1.7 CFU/25 g was observed. The specificity, relative sensitivity and accuracy of full methodology were 100% and the use of the NC-IAC allowed the reliability of the results without interfering with the sensitivity of the methodology. The described study proved to obtain results comparable to those of probe-based qPCR, and more economically than classical high resolution melting qPCR, being both important aspects for its implementation in the food industry.
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Affiliation(s)
- Sarah Azinheiro
- Food Quality and Safety Research Group, International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal; (S.A.); (J.C.); (M.P.)
- College of Pharmacy/School of Veterinary Sciences, University of Santiago de Compostela, Campus Vida, E-15782 Santiago de Compostela, Spain
| | - Joana Carvalho
- Food Quality and Safety Research Group, International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal; (S.A.); (J.C.); (M.P.)
- College of Pharmacy/School of Veterinary Sciences, University of Santiago de Compostela, Campus Vida, E-15782 Santiago de Compostela, Spain
| | - Marta Prado
- Food Quality and Safety Research Group, International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal; (S.A.); (J.C.); (M.P.)
| | - Alejandro Garrido-Maestu
- Food Quality and Safety Research Group, International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal; (S.A.); (J.C.); (M.P.)
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25
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Krypotou E, Scortti M, Grundström C, Oelker M, Luisi BF, Sauer-Eriksson AE, Vázquez-Boland J. Control of Bacterial Virulence through the Peptide Signature of the Habitat. Cell Rep 2020; 26:1815-1827.e5. [PMID: 30759392 PMCID: PMC6389498 DOI: 10.1016/j.celrep.2019.01.073] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/09/2018] [Accepted: 01/17/2019] [Indexed: 12/20/2022] Open
Abstract
To optimize fitness, pathogens selectively activate their virulence program upon host entry. Here, we report that the facultative intracellular bacterium Listeria monocytogenes exploits exogenous oligopeptides, a ubiquitous organic N source, to sense the environment and control the activity of its virulence transcriptional activator, PrfA. Using a genetic screen in adsorbent-treated (PrfA-inducing) medium, we found that PrfA is functionally regulated by the balance between activating and inhibitory nutritional peptides scavenged via the Opp transport system. Activating peptides provide essential cysteine precursor for the PrfA-inducing cofactor glutathione (GSH). Non-cysteine-containing peptides cause promiscuous PrfA inhibition. Biophysical and co-crystallization studies reveal that peptides inhibit PrfA through steric blockade of the GSH binding site, a regulation mechanism directly linking bacterial virulence and metabolism. L. monocytogenes mutant analysis in macrophages and our functional data support a model in which changes in the balance of antagonistic Opp-imported oligopeptides promote PrfA induction intracellularly and PrfA repression outside the host. Listeria PrfA virulence regulation is controlled by antagonistic nutritional peptides Opp-imported peptides regulate PrfA upstream of the activating cofactor GSH PrfA is activated by peptides that provide essential cysteine for GSH biosynthesis Blockade of PrfA’s GSH binding site by peptides inhibits virulence gene activation
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Affiliation(s)
- Emilia Krypotou
- Microbial Pathogenesis Group, Infection Medicine, Edinburgh Medical School (Biomedical Sciences) and The Roslin Institute, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Mariela Scortti
- Microbial Pathogenesis Group, Infection Medicine, Edinburgh Medical School (Biomedical Sciences) and The Roslin Institute, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Christin Grundström
- Department of Chemistry and Umeå Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden
| | - Melanie Oelker
- Department of Chemistry and Umeå Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | | | - José Vázquez-Boland
- Microbial Pathogenesis Group, Infection Medicine, Edinburgh Medical School (Biomedical Sciences) and The Roslin Institute, University of Edinburgh, Edinburgh EH16 4SB, UK.
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Zeng Z, Smid EJ, Boeren S, Notebaart RA, Abee T. Bacterial Microcompartment-Dependent 1,2-Propanediol Utilization Stimulates Anaerobic Growth of Listeria monocytogenes EGDe. Front Microbiol 2019; 10:2660. [PMID: 31803170 PMCID: PMC6873790 DOI: 10.3389/fmicb.2019.02660] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/31/2019] [Indexed: 12/22/2022] Open
Abstract
Bacterial microcompartments (BMCs) are proteinaceous organelles that optimize specific metabolic pathways referred to as metabolosomes involving transient production of toxic volatile metabolites such as aldehydes. Previous bioinformatics analysis predicted the presence of BMCs in 23 bacterial phyla including foodborne pathogens and a link with gene clusters for the utilization of host-derived substrates such as 1,2-propanediol utilization, i.e., the Pdu cluster. Although, transcriptional regulation of the Pdu cluster and its role in Listeria monocytogenes virulence in animal models have recently been reported, the experimental identification and the physiological role of BMCs in L. monocytogenes is still unexplored. Here, we ask whether BMCs could enable utilization of 1,2-propanediol (Pd) in L. monocytogenes under anaerobic conditions. Using L. monocytogenes EGDe as a model strain, we could demonstrate efficient utilization of Pd with concomitant production of 1-propanol and propionate after 24 h of anaerobic growth, while the utilization was significantly reduced in aerobic conditions. In line with this, expression of genes encoding predicted shell proteins and the signature enzyme propanediol dehydratase is upregulated more than 20-fold in cells anaerobically grown in Pdu-induced versus non-induced control conditions. Additional proteomics analysis confirmed the presence of BMC shell proteins and Pdu enzymes in cells that show active degradation of Pd. Furthermore, using transmission electron microscopy, BMC structures have been detected in these cells linking gene expression, protein composition, and BMCs to activation of the Pdu cluster in anaerobic growth of L. monocytogenes. Studies in defined minimal medium with Pd as an energy source showed a significant increase in cell numbers, indicating that Pdu and the predicted generation of ATP in the conversion of propionyl-phosphate to the end product propionate can support anaerobic growth of L. monocytogenes. Our findings may suggest a role for BMC-dependent utilization of Pd in L. monocytogenes growth, transmission, and interaction with the human host.
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Affiliation(s)
- Zhe Zeng
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, Netherlands
| | - Eddy J Smid
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
| | - Richard A Notebaart
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, Netherlands
| | - Tjakko Abee
- Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, Netherlands
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Capita R, Felices-Mercado A, García-Fernández C, Alonso-Calleja C. Characterization of Listeria Monocytogenes Originating from the Spanish Meat-Processing Chain. Foods 2019; 8:E542. [PMID: 31684121 PMCID: PMC6915328 DOI: 10.3390/foods8110542] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/16/2022] Open
Abstract
Using agglutination techniques, 118 Listeria monocytogenes isolates from red meat and poultry were serotyped. Strains were ascribed to the serotypes 4b/4e (44.1% of the strains), 1/2 (a, b or c; 28.0%), 4c (6.8%), 4d/4e (5.9%) and 3 (a, b or c; 2.5%). Among these are the serotypes most frequently involved in cases of human listeriosis. The susceptibility of 72 strains to 26 antibiotics of clinical importance was determined by disc diffusion (Clinical and Laboratory Standards Institute; CLSI). High levels of resistance were observed to cefoxitin (77.8% of the strains showed resistance), cefotaxime (62.5%), cefepime (73.6%), and nalidixic acid (97.2%), nitrofurantoin (51.4%) and oxacillin (93.1%). Less than 3% of the strains showed resistance to the antibiotic classes used in human listeriosis therapy (i.e., ampicillin, gentamicin, rifampicin, chloramphenicol, enrofloxacin, vancomycin, trimethoprim-sulfamethoxazole, erythromycin, and tetracycline). The influence of species and serotype on the growth kinetics (modified Gompertz equation) and on the adhesion ability (crystal violet staining) of nine isolates of L. monocytogenes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4a, 4b, and 4d), and one strain of Listeria ivanovii were investigated. The maximum growth rate (ΔOD420-580/h) varied between 0.073 ± 0.018 (L. monocytogenes 1/2a) and 0.396 ± 0.026 (L. monocytogenes 4b). The isolates of L. monocytogenes belonging to serotypes 3a and 4a, as well as L. ivanovii, showed a greater (p < 0.05) biofilm-forming ability than did the remaining strains, including those that belong to the serotypes commonly implied in human listeriosis (1/2a, 1/2b, 1/2c and 4b). The need for training in good hygiene practices during the handling of meat and poultry is highlighted to reduce the risk of human listeriosis.
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Affiliation(s)
- Rosa Capita
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
- Institute of Food Science and Technology, University of León, León E-24071, Spain.
| | - Amanda Felices-Mercado
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
| | - Camino García-Fernández
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
- Institute of Food Science and Technology, University of León, León E-24071, Spain.
| | - Carlos Alonso-Calleja
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, León E-24071, Spain.
- Institute of Food Science and Technology, University of León, León E-24071, Spain.
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Abstract
Bacterial metabolism represents the biochemical space that bacteria can manipulate to produce energy, reducing equivalents and building blocks for replication. Gram-positive pathogens, such as Listeria monocytogenes, show remarkable flexibility, which allows for exploitation of diverse biological niches from the soil to the intracytosolic space. Although the human host represents a potentially rich source for nutrient acquisition, competition for nutrients with the host and hostile host defenses can constrain bacterial metabolism by various mechanisms, including nutrient sequestration. Here, we review metabolism in the model Gram-positive bacterium, L. monocytogenes, and highlight pathways that enable the replication, survival, and virulence of this bacterial pathogen.
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Copper-Induced Expression of a Transmissible Lipoprotein Intramolecular Transacylase Alters Lipoprotein Acylation and the Toll-Like Receptor 2 Response to Listeria monocytogenes. J Bacteriol 2019; 201:JB.00195-19. [PMID: 30988036 DOI: 10.1128/jb.00195-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/08/2019] [Indexed: 12/30/2022] Open
Abstract
Bacterial lipoproteins are globular proteins anchored to the extracytoplasmic surfaces of cell membranes through lipidation at a conserved N-terminal cysteine. Lipoproteins contribute to an array of important cellular functions for bacteria, as well as being a focal point for innate immune system recognition through binding to Toll-like receptor 2 (TLR2) heterodimer complexes. Although lipoproteins are conserved among nearly all classes of bacteria, the presence and type of α-amino-linked acyl chain are highly variable and even strain specific within a given bacterial species. The reason for lyso-lipoprotein formation and N-acylation variability in general is presently not fully understood. In Enterococcus faecalis, lipoproteins are anchored by an N-acyl-S-monoacyl-glyceryl cysteine (lyso form) moiety installed by a chromosomally encoded lipoprotein intramolecular transacylase (Lit). Here, we describe a mobile genetic element common to environmental isolates of Listeria monocytogenes and Enterococcus spp. encoding a functional Lit ortholog (Lit2) that is cotranscribed with several well-established copper resistance determinants. Expression of Lit2 is tightly regulated, and induction by copper converts lipoproteins from the diacylglycerol-modified form characteristic of L. monocytogenes type strains to the α-amino-modified lyso form observed in E. faecalis Conversion to the lyso form through either copper addition to media or constitutive expression of lit2 decreases TLR2 recognition when using an activated NF-κB secreted embryonic alkaline phosphatase reporter assay. While lyso formation significantly diminishes TLR2 recognition, lyso-modified lipoprotein is still predominantly recognized by the TLR2/TLR6 heterodimer.IMPORTANCE The induction of lipoprotein N-terminal remodeling in response to environmental copper in Gram-positive bacteria suggests a more general role in bacterial cell envelope physiology. N-terminal modification by lyso formation, in particular, simultaneously modulates the TLR2 response in direct comparison to their diacylglycerol-modified precursors. Thus, use of copper as a frontline antimicrobial control agent and ensuing selection raises the potential of diminished innate immune sensing and enhanced bacterial virulence.
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Lensmire JM, Hammer ND. Nutrient sulfur acquisition strategies employed by bacterial pathogens. Curr Opin Microbiol 2019; 47:52-58. [DOI: 10.1016/j.mib.2018.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/04/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
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Crauwels P, Schäfer L, Weixler D, Bar NS, Diep DB, Riedel CU, Seibold GM. Intracellular pHluorin as Sensor for Easy Assessment of Bacteriocin-Induced Membrane-Damage in Listeria monocytogenes. Front Microbiol 2019; 9:3038. [PMID: 30619129 PMCID: PMC6297387 DOI: 10.3389/fmicb.2018.03038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 11/26/2018] [Indexed: 11/13/2022] Open
Abstract
Bacteriocins are antimicrobial peptides naturally produced by many bacteria and were shown to be effective against various pathogens including Listeria monocytogenes. L. monocytogenes is a food-borne pathogen that frequently causes disease outbreaks around the world with fatal outcomes in at-risk individuals. Thus, bacteriocins are a promising solution to prevent contaminations with L. monocytogenes and other microorganisms during food production and preservation. In the present study, we constructed L. monocytogenes EGD-e/pNZ-Phelp-pHluorin, a strain that constitutively expresses the pH-sensitive fluorescent protein pHluorin, as a sensor strain to detect disruption of the pH gradient by the membrane-damaging activity of bacteriocins. The ratiometric fluorescence properties of pHluorin were validated both in crude extracts and permeabilized cells of this sensor strain. L. monocytogenes EGD-e/pNZ-Phelp-pHluorin was used to assess membrane damaging activity of the bacteriocins nisin A and pediocin PA-1 and to determine the minimal concentrations required for full disruption of the pH gradient across the membrane. Moreover, the sensor strain proved useful to analyze the presence of compounds affecting membrane integrity in supernatants of a nisin Z-producing Lactococcus lactis strain at different timepoints during growth. Supernatants of this strain that were active in disrupting the pH gradient across the membrane were also shown to inhibit growth of L. monocytogenes. In summary, the presented results suggest that the generated sensor strain is a convenient, fast and reliable tool to identify and characterize novel bacteriocins and other compounds that target membrane integrity.
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Affiliation(s)
- Peter Crauwels
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Leonie Schäfer
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Dominik Weixler
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Nadav S Bar
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Dzung B Diep
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Gerd M Seibold
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
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Prezioso SM, Xue K, Leung N, Gray-Owen SD, Christendat D. Shikimate Induced Transcriptional Activation of Protocatechuate Biosynthesis Genes by QuiR, a LysR-Type Transcriptional Regulator, in Listeria monocytogenes. J Mol Biol 2018. [PMID: 29530613 DOI: 10.1016/j.jmb.2018.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Listeria monocytogenes is a common foodborne bacterial pathogen that contaminates plant and animal consumable products. The persistent nature of L. monocytogenes is associated with millions of dollars in food recalls annually. Here, we describe the role of shikimate in directly modulating the expression of genes encoding enzymes for the conversion of quinate and shikimate metabolites to protocatechuate. In L. monocytogenes, these genes are found within two operons, named qui1 and qui2. In addition, a gene named quiR, encoding a LysR-Type Transcriptional Regulator (QuiR), is located immediately upstream of the qui1 operon. Transcriptional lacZ-promoter fusion experiments show that QuiR induces gene expression of both qui1 and qui2 operons in the presence of shikimate. Furthermore, co-crystallization of the QuiR effector binding domain in complex with shikimate provides insights into the mechanism of activation of this regulator. Together these data show that upon shikimate accumulation, QuiR activates the transcription of genes encoding enzymes involved in shikimate and quinate utilization for the production of protocatechuate. Furthermore, the accumulation of protocatechuate leads to the inhibition of Listeria growth. Since protocatechuate is not known to be utilized by Listeria, its role is distinct from those established in other bacteria.
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Affiliation(s)
- Stephanie M Prezioso
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - Kevin Xue
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - Nelly Leung
- Department of Molecular Genetics, University of Toronto, 1 King's College Cir, Toronto, Ontario, Canada M5S 1A8
| | - Scott D Gray-Owen
- Department of Molecular Genetics, University of Toronto, 1 King's College Cir, Toronto, Ontario, Canada M5S 1A8
| | - Dinesh Christendat
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2; Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2.
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CodY-Mediated c-di-GMP-Dependent Inhibition of Mammalian Cell Invasion in Listeria monocytogenes. J Bacteriol 2018; 200:JB.00457-17. [PMID: 29229701 DOI: 10.1128/jb.00457-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/28/2017] [Indexed: 01/11/2023] Open
Abstract
Elevated levels of the second messenger c-di-GMP suppress virulence in diverse pathogenic bacteria, yet mechanisms are poorly characterized. In the foodborne pathogen Listeria monocytogenes, high c-di-GMP levels inhibit mammalian cell invasion. Here, we show that invasion is impaired because of the decreased expression levels of internalin genes whose products are involved in invasion. We further show that at high c-di-GMP levels, the expression of the entire virulence regulon is suppressed, and so is the expression of the prfA gene encoding the master activator of the virulence regulon. Analysis of mechanisms controlling prfA expression pointed to the transcription factor CodY as a c-di-GMP-sensitive component. In high-c-di-GMP strains, codY gene expression is decreased, apparently due to the lower activity of CodY, which functions as an activator of codY transcription. We found that listerial CodY does not bind c-di-GMP in vitro and therefore investigated whether c-di-GMP levels affect two known cofactors of listerial CodY, branched-chain amino acids and GTP. Our manipulation of branched-chain amino acid levels did not perturb the c-di-GMP effect; however, our replacement of listerial CodY with the streptococcal CodY homolog, whose activity is GTP independent, abolished the c-di-GMP effect. The results of this study suggest that elevated c-di-GMP levels decrease the activity of the coordinator of metabolism and virulence, CodY, possibly via lower GTP levels, and that decreased CodY activity suppresses L. monocytogenes virulence by the decreased expression of the PrfA virulence regulon.IMPORTANCEListeria monocytogenes is a pathogen causing listeriosis, a disease responsible for the highest mortality rate among foodborne diseases. Understanding how the virulence of this pathogen is regulated is important for developing treatments to decrease the frequency of listerial infections in susceptible populations. In this study, we describe the mechanism through which elevated levels of the second messenger c-di-GMP inhibit listerial invasion in mammalian cells. Inhibition is caused by the decreased activity of the transcription factor CodY that coordinates metabolism and virulence.
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Chen GY, Pensinger DA, Sauer JD. Listeria monocytogenes cytosolic metabolism promotes replication, survival, and evasion of innate immunity. Cell Microbiol 2017; 19:10.1111/cmi.12762. [PMID: 28656691 PMCID: PMC5587384 DOI: 10.1111/cmi.12762] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/18/2017] [Accepted: 06/22/2017] [Indexed: 12/28/2022]
Abstract
Listeria monocytogenes, the causative agent of listeriosis, is an intracellular pathogen that is exquisitely evolved to survive and replicate in the cytosol of eukaryotic cells. Eukaryotic cells typically restrict bacteria from colonising the cytosol, likely through a combination of cell autonomous defences, nutritional immunity, and innate immune responses including induction of programmed cell death. This suggests that L. monocytogenes and other professional cytosolic pathogens possess unique metabolic adaptations, not only to support replication but also to facilitate resistance to host-derived stresses/defences and avoidance of innate immune activation. In this review, we outline our current understanding of L. monocytogenes metabolism in the host cytosol and highlight major metabolic processes which promote intracellular replication and survival.
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Affiliation(s)
- Grischa Y. Chen
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706
| | - Daniel A. Pensinger
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706
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35
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Sherratt AR, Rouleau Y, Luebbert C, Strmiskova M, Veres T, Bidawid S, Corneau N, Pezacki JP. Rapid Screening and Identification of Living Pathogenic Organisms via Optimized Bioorthogonal Non-canonical Amino Acid Tagging. Cell Chem Biol 2017; 24:1048-1055.e3. [PMID: 28757183 DOI: 10.1016/j.chembiol.2017.06.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/19/2017] [Accepted: 06/27/2017] [Indexed: 10/19/2022]
Abstract
Pathogenic bacteria can be a major cause of illness from environmental sources as well as the consumption of contaminated products, giving rise to public health concerns globally. The surveillance of such living organisms in food and water supplies remains an important challenge in mitigating their deleterious societal effects. Here, we have developed an optimized bioorthogonal non-canonical amino acid tagging approach to the imaging, capture, and interrogation of shigatoxigenic/verotoxigenic Escherichia coli (VTEC) and Listeria that enables the distinction between living wild-type pathogenic bacteria. The approaches utilize homopropargylglycine (HPG), as well as optimized growth media, that restricts endogenous methionine biosynthesis in a variety of species of public health concern. Endogenous methionine residues are then replaced with HPG, which can then be modified using a myriad of compatible bioorthogonal reactions for tagging of exclusively live bacteria. The methods reported allow for the very rapid screening and identification of living pathogenic organisms.
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Affiliation(s)
- Allison Rae Sherratt
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada; Life Sciences Division, National Research Council of Canada, 100 Sussex Drive, Ottawa K1A 0R6, Canada
| | - Yanouchka Rouleau
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada; Life Sciences Division, National Research Council of Canada, 100 Sussex Drive, Ottawa K1A 0R6, Canada
| | | | - Miroslava Strmiskova
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada
| | - Teodor Veres
- Life Sciences Division, National Research Council of Canada, 100 Sussex Drive, Ottawa K1A 0R6, Canada
| | - Sabah Bidawid
- Health Canada, Bureau of Microbial Hazards, Ottawa K1A 0K9, Canada
| | - Nathalie Corneau
- Health Canada, Bureau of Microbial Hazards, Ottawa K1A 0K9, Canada
| | - John Paul Pezacki
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada; Life Sciences Division, National Research Council of Canada, 100 Sussex Drive, Ottawa K1A 0R6, Canada.
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Reddy S, Turaga G, Abdelhamed H, Banes MM, Wills RW, Lawrence ML. Listeria monocytogenes PdeE, a phosphodiesterase that contributes to virulence and has hydrolytic activity against cyclic mononucleotides and cyclic dinucleotides. Microb Pathog 2017; 110:399-408. [PMID: 28711509 DOI: 10.1016/j.micpath.2017.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/27/2017] [Accepted: 07/11/2017] [Indexed: 12/25/2022]
Abstract
We have identified and partially characterized a putative HD domain hydrolase, LMOf2365_2464, which is highly expressed during listerial intracellular replication. LMOf2365_2464 is annotated as a putative HD domain-containing hydrolase. The ability of an isogenic mutant strain, F2365Δ2464, to adhere, invade and replicate in intestinal epithelial cells (Caco-2) was significantly lower than parent strain F2365. Colonization of mouse liver and spleen by L. monocytogenes F2365 was significantly higher than it was for the mutant. The recombinant protein showed phosphodiesterase activity in the presence of divalent metal ions, indicating its role in nucleotide metabolism. It has activity against several cyclic nucleotides and cyclic dinucleotides, but its strongest activity is against cyclic di-AMP and cyclic AMP. Based on this enzymatic activity, we designated LMOf2365_2464 phosphodiesterase E (PdeE).
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Affiliation(s)
- Swetha Reddy
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Gokul Turaga
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Hossam Abdelhamed
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Michelle M Banes
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Robert W Wills
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Mark L Lawrence
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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Fast detection of Listeria monocytogenes through a nanohybrid quantum dot complex. Anal Bioanal Chem 2017; 409:5359-5371. [DOI: 10.1007/s00216-017-0481-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/27/2017] [Accepted: 06/21/2017] [Indexed: 02/05/2023]
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Branck TA, Hurley MJ, Prata GN, Crivello CA, Marek PJ. Efficacy of a Sonicating Swab for Removal and Capture of Listeria monocytogenes in Biofilms on Stainless Steel. Appl Environ Microbiol 2017; 83:e00109-17. [PMID: 28314729 PMCID: PMC5440701 DOI: 10.1128/aem.00109-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/15/2017] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes is of great concern in food processing facilities because it persists in biofilms, facilitating biotransfer. Stainless steel is commonly used for food contact surfaces and transport containers. L. monocytogenes biofilms on stainless steel served as a model system for surface sampling, to test the performance of a sonicating swab in comparison with a standard cotton swab. Swab performance and consistency were determined using total viable counts. Stainless steel coupons sampled with both types of swabs were examined using scanning electron microscopy, to visualize biofilms and surface structures (i.e., polishing grooves and scratches). Laser scanning confocal microscopy was used to image and to quantitate the biofilms remaining after sampling with each swab type. The total viable counts were significantly higher (P ≤ 0.05) with the sonicating swab than with the standard swab in each trial. The sonicating swab was more consistent in cell recovery than was the standard swab, with coefficients of variation ranging from 8.9% to 12.3% and from 7.1% to 37.6%, respectively. Scanning electron microscopic imaging showed that biofilms remained in the polished grooves of the coupons sampled with the standard swab but were noticeably absent with the sonicating swab. Percent area measurements of biofilms remaining on the stainless steel coupons showed significantly (P ≤ 0.05) less biofilm remaining when the sonicating swab was used (median, 1.1%), compared with the standard swab (median, 70.4%). The sonicating swab provided greater recovery of cells, with more consistency, than did the standard swab, and it is employs sonication, suction, and scrubbing.IMPORTANCE Inadequate surface sampling can result in foodborne illness outbreaks from biotransfer, since verification of sanitization protocols relies on surface sampling and recovery of microorganisms for detection and enumeration. Swabbing is a standard method for microbiological sampling of surfaces. Although swabbing offers portability and ease of use, there are limitations, such as high user variability and low recovery rates, which can be attributed to many different causes. This study demonstrates some benefits that a sonicating swab has over a standard swab for removal and collection of microbiological samples from a surface, to provide better verification of surface cleanliness and to help decrease the potential for biotransfer of pathogens into foods.
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Affiliation(s)
- Tobyn A Branck
- Biological Science and Technology Team, Natick Soldier Research, Development and Engineering Center, Natick, Massachusetts, USA
| | - Matthew J Hurley
- Design, Engineering, and Fabrication Team, Engineering Cell, Natick Soldier Research, Development and Engineering Center, Natick, Massachusetts, USA
| | - Gianna N Prata
- Food Protection and Innovative Packaging Team, Natick Soldier Research, Development and Engineering Center, Natick, Massachusetts, USA
| | - Christina A Crivello
- Food Protection and Innovative Packaging Team, Natick Soldier Research, Development and Engineering Center, Natick, Massachusetts, USA
| | - Patrick J Marek
- Food Protection and Innovative Packaging Team, Natick Soldier Research, Development and Engineering Center, Natick, Massachusetts, USA
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Whiteley AT, Garelis NE, Peterson BN, Choi PH, Tong L, Woodward JJ, Portnoy DA. c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation. Mol Microbiol 2017; 104:212-233. [PMID: 28097715 DOI: 10.1111/mmi.13622] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2017] [Indexed: 12/26/2022]
Abstract
Cyclic diadenosine monophosphate (c-di-AMP) is a conserved nucleotide second messenger critical for bacterial growth and resistance to cell wall-active antibiotics. In Listeria monocytogenes, the sole diadenylate cyclase, DacA, is essential in rich, but not synthetic media and ΔdacA mutants are highly sensitive to the β-lactam antibiotic cefuroxime. In this study, loss of function mutations in the oligopeptide importer (oppABCDF) and glycine betaine importer (gbuABC) allowed ΔdacA mutants to grow in rich medium. Since oligopeptides were sufficient to inhibit growth of the ΔdacA mutant we hypothesized that oligopeptides act as osmolytes, similar to glycine betaine, to disrupt intracellular osmotic pressure. Supplementation with salt stabilized the ΔdacA mutant in rich medium and restored cefuroxime resistance. Additional suppressor mutations in the acetyl-CoA binding site of pyruvate carboxylase (PycA) rescued cefuroxime resistance and resulted in a 100-fold increase in virulence of the ΔdacA mutant. PycA is inhibited by c-di-AMP and these mutations prompted us to examine the role of TCA cycle enzymes. Inactivation of citrate synthase, but not down-stream enzymes suppressed ΔdacA phenotypes. These data suggested that c-di-AMP modulates central metabolism at the pyruvate node to moderate citrate production and indeed, the ΔdacA mutant accumulated six times the concentration of citrate present in wild-type bacteria.
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Affiliation(s)
- Aaron T Whiteley
- Graduate Group in Infectious Diseases and Immunity, School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Nicholas E Garelis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Bret N Peterson
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, CA, USA
| | - Philip H Choi
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,School of Public Health, University of California, Berkeley, Berkeley, CA, USA
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Lobete MM, Noriega E, Batalha MA, de Beurme S, Van de Voorde I, Van Impe JF. Effect of tagatose on growth dynamics of Salmonella Typhimurium and Listeria monocytogenes in media with different levels of structural complexity and in UHT skimmed milk. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.05.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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41
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Stevia-based sweeteners as a promising alternative to table sugar: The effect on Listeria monocytogenes and Salmonella Typhimurium growth dynamics. Int J Food Microbiol 2017; 245:38-52. [DOI: 10.1016/j.ijfoodmicro.2017.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 12/21/2016] [Accepted: 01/17/2017] [Indexed: 11/22/2022]
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L-glutamine Induces Expression of Listeria monocytogenes Virulence Genes. PLoS Pathog 2017; 13:e1006161. [PMID: 28114430 PMCID: PMC5289647 DOI: 10.1371/journal.ppat.1006161] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 02/02/2017] [Accepted: 12/30/2016] [Indexed: 12/27/2022] Open
Abstract
The high environmental adaptability of bacteria is contingent upon their ability to sense changes in their surroundings. Bacterial pathogen entry into host poses an abrupt and dramatic environmental change, during which successful pathogens gauge multiple parameters that signal host localization. The facultative human pathogen Listeria monocytogenes flourishes in soil, water and food, and in ~50 different animals, and serves as a model for intracellular infection. L. monocytogenes identifies host entry by sensing both physical (e.g., temperature) and chemical (e.g., metabolite concentrations) factors. We report here that L-glutamine, an abundant nitrogen source in host serum and cells, serves as an environmental indicator and inducer of virulence gene expression. In contrast, ammonia, which is the most abundant nitrogen source in soil and water, fully supports growth, but fails to activate virulence gene transcription. We demonstrate that induction of virulence genes only occurs when the Listerial intracellular concentration of L-glutamine crosses a certain threshold, acting as an on/off switch: off when L-glutamine concentrations are below the threshold, and fully on when the threshold is crossed. To turn on the switch, L-glutamine must be present, and the L-glutamine high affinity ABC transporter, GlnPQ, must be active. Inactivation of GlnPQ led to complete arrest of L-glutamine uptake, reduced type I interferon response in infected macrophages, dramatic reduction in expression of virulence genes, and attenuated virulence in a mouse infection model. These results may explain observations made with other pathogens correlating nitrogen metabolism and virulence, and suggest that gauging of L-glutamine as a means of ascertaining host localization may be a general mechanism.
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Pinheiro J, Reis O, Vieira A, Moura IM, Zanolli Moreno L, Carvalho F, Pucciarelli MG, García-Del Portillo F, Sousa S, Cabanes D. Listeria monocytogenes encodes a functional ESX-1 secretion system whose expression is detrimental to in vivo infection. Virulence 2016; 8:993-1004. [PMID: 27723420 DOI: 10.1080/21505594.2016.1244589] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Bacterial pathogenicity deeply depends on the ability to secrete virulence factors that bind specific targets on host cells and manipulate host responses. The Gram-positive bacterium Listeria monocytogenes is a human foodborne pathogen that remains a serious public health concern. To transport proteins across its cell envelope, this facultative intracellular pathogen engages a set of specialized secretion systems. Here we show that L. monocytogenes EGDe uses a specialized secretion system, named ESX-1, to secrete EsxA, a homolog of the virulence determinants ESAT-6 and EsxA of Mycobacterium tuberculosis and Staphylococcus aureus, respectively. Our data show that the L. monocytogenes ESX-1 secretion system and its substrates are dispensable for bacterial invasion and intracellular multiplication in eukaryotic cell lines. Surprisingly, we found that the EssC-dependent secretion of EsxA has a detrimental effect on L. monocytogenes in vivo infection.
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Affiliation(s)
- Jorge Pinheiro
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal.,c Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto , Porto , Portugal
| | - Olga Reis
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal.,c Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto , Porto , Portugal
| | - Ana Vieira
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal
| | - Ines M Moura
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal
| | - Luisa Zanolli Moreno
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal.,d Laboratório de Saúde Pública , Faculdade de Saúde Pública, Universidade de São Paulo , São Paulo , Brazil
| | - Filipe Carvalho
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal.,c Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto , Porto , Portugal
| | - M Graciela Pucciarelli
- e Centro Nacional de Biotecnología-CSIC (CNB-CSIC) , Madrid , Spain.,f Departamento de Biología Molecular , Universidad Autónoma de Madrid, Centro de Biología Molecular "Severo Ochoa" (CBMSO-CSIC) , Madrid , Spain
| | | | - Sandra Sousa
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal
| | - Didier Cabanes
- a Instituto de Investigação e Inovação em Saúde - i3S, Universidade do Porto , Porto , Portugal.,b Group of Molecular Microbiology , Instituto de Biologia Molecular e Celular - IBMC , Porto , Portugal
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Jarvis NA, O'Bryan CA, Ricke SC, Johnson MG, Crandall PG. A review of minimal and defined media for growth of Listeria monocytogenes. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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45
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Seel W, Derichs J, Lipski A. Increased Biomass Production by Mesophilic Food-Associated Bacteria through Lowering the Growth Temperature from 30°C to 10°C. Appl Environ Microbiol 2016; 82:3754-3764. [PMID: 27084015 PMCID: PMC4907174 DOI: 10.1128/aem.00211-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/11/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Five isolates from chilled food and refrigerator inner surfaces and closely related reference strains of the species Escherichia coli, Listeria monocytogenes, Staphylococcus xylosus, Bacillus cereus, Pedobacter nutrimenti, and Pedobacter panaciterrae were tested for the effect of growth temperature (30°C and 10°C) on biomass formation. Growth was monitored via optical density, and biomass formation was measured at the early stationary phase based on the following parameters in complex and defined media: viable cell count, total cell count, cell dry weight, whole-cell protein content, and cell morphology. According to the lack of growth at 1°C, all strains were assigned to the thermal class of mesophiles. Glucose and ammonium consumption related to cell yield were analyzed in defined media. Except for the protein content, temperature had a significant (t test, P < 0.05) effect on all biomass formation parameters for each strain. The results show a significant difference between the isolates and the related reference strains. Isolates achieved an increase in biomass production between 20% and 110% at the 10°C temperature, which is 15 to 25°C lower than their maximum growth rate temperatures. In contrast, reference strains showed a maximum increase of only about 25%, and some reference strains showed no increase or a decrease of approximately 25%. As expected, growth rates for all strains were higher at 30°C than at 10°C, while biomass production for isolates was higher at 10°C than at 30°C. In contrast, the reference strains showed similar growth yields at the two temperatures. This also demonstrates for mesophilic bacterial strains more efficient nutrient assimilation during growth at low temperatures. Until now, this characteristic was attributed only to psychrophilic microorganisms. IMPORTANCE For several psychrophilic species, increased biomass formation was described at temperatures lower than optimum growth temperatures, which are defined by the highest growth rate. This work shows increased biomass formation at low growth temperatures for mesophilic isolates. A comparison with closely related reference strains from culture collections showed a significantly smaller increase or no increase in biomass formation. This indicates a loss of specific adaptive mechanisms (e.g., cold adaptation) for mesophiles during long-term cultivation. The increased biomass production for mesophiles under low-temperature conditions opens new avenues for a more efficient biotechnological transformation of nutrients to microbial biomass. These findings may also be important for risk assessment of cooled foods since risk potential is often correlated with the cell numbers present in food samples.
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Affiliation(s)
- Waldemar Seel
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Ernährungs- und Lebensmittelwissenschaften, Abteilung Lebensmittelmikrobiologie und -hygiene, Bonn, Germany
| | - Julia Derichs
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Ernährungs- und Lebensmittelwissenschaften, Abteilung Lebensmittelmikrobiologie und -hygiene, Bonn, Germany
| | - André Lipski
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Ernährungs- und Lebensmittelwissenschaften, Abteilung Lebensmittelmikrobiologie und -hygiene, Bonn, Germany
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Metabolic Adaptations of Intracellullar Bacterial Pathogens and their Mammalian Host Cells during Infection ("Pathometabolism"). Microbiol Spectr 2016; 3. [PMID: 26185075 DOI: 10.1128/microbiolspec.mbp-0002-2014] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several bacterial pathogens that cause severe infections in warm-blooded animals, including humans, have the potential to actively invade host cells and to efficiently replicate either in the cytosol or in specialized vacuoles of the mammalian cells. The interaction between these intracellular bacterial pathogens and the host cells always leads to multiple physiological changes in both interacting partners, including complex metabolic adaptation reactions aimed to promote proliferation of the pathogen within different compartments of the host cells. In this chapter, we discuss the necessary nutrients and metabolic pathways used by some selected cytosolic and vacuolar intracellular pathogens and--when available--the links between the intracellular bacterial metabolism and the expression of the virulence genes required for the intracellular bacterial replication cycle. Furthermore, we address the growing evidence that pathogen-specific factors may also trigger metabolic responses of the infected mammalian cells affecting the carbon and nitrogen metabolism as well as defense reactions. We also point out that many studies on the metabolic host cell responses induced by the pathogens have to be scrutinized due to the use of established cell lines as model host cells, as these cells are (in the majority) cancer cells that exhibit a dysregulated primary carbon metabolism. As the exact knowledge of the metabolic host cell responses may also provide new concepts for antibacterial therapies, there is undoubtedly an urgent need for host cell models that more closely reflect the in vivo infection conditions.
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Kutzner E, Kern T, Felsl A, Eisenreich W, Fuchs TM. Isotopologue profiling of the listerial N-metabolism. Mol Microbiol 2016; 100:315-27. [PMID: 26699934 DOI: 10.1111/mmi.13318] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2015] [Indexed: 11/26/2022]
Abstract
The nitrogen (N-) sources and the relative contribution of a nitrogenous nutrient to the N-pool of the gram-positive pathogen Listeria monocytogenes are largely unknown. Therefore, (15) N-isotopologue profiling was established to study the N-metabolism of L. monocytogenes. The pathogen was grown in a defined minimal medium supplemented with potential (15) N-labeled nutrients. The bacteria were harvested and hydrolysed under acidic conditions, and the resulting amino acids were analysed by GC-MS, revealing (15) N-enrichments and isotopomeric compositions of amino acids. The differential (15) N-profiles showed the substantial and simultaneous usage of ammonium, glutamine, methionine, and, to a lower extent, the branched-chain amino acids valine, leucine, and isoleucine for anabolic purposes, with a significant preference for ammonium. In contrast, arginine, histidine and cysteine were directly incorporated into proteins. L. monocytogenes is able to replace glutamine with ethanolamine or glucosamine as amino donors for feeding the core N-metabolism. Perturbations of N-fluxes caused by gene deletions demonstrate the involvement of ethanolamine ammonia lyase, and suggest a role of the regulator GlnK of L. monocytogenes distinct from that of Escherichia coli. The metabolism of nitrogenous nutrients reflects the high flexibility of this pathogenic bacterium in exploiting N-sources that could also be relevant for its proliferation during infection.
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Affiliation(s)
- Erika Kutzner
- Lehrstuhl für Biochemie, Technische Universität München, D-85747, Garching, Germany
| | - Tanja Kern
- Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Angela Felsl
- Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Wolfgang Eisenreich
- Lehrstuhl für Biochemie, Technische Universität München, D-85747, Garching, Germany
| | - Thilo M Fuchs
- Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
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48
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Nowak J, Cruz CD, Palmer J, Fletcher GC, Flint S. Biofilm formation of the L. monocytogenes strain 15G01 is influenced by changes in environmental conditions. J Microbiol Methods 2015; 119:189-95. [PMID: 26524221 DOI: 10.1016/j.mimet.2015.10.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/27/2015] [Accepted: 10/28/2015] [Indexed: 02/06/2023]
Abstract
Listeria monocytogenes 15G01, a strain belonging to the persistent pulsotype 5132, was isolated from a seafood processing plant in New Zealand. Simple monoculture assays using crystal violet staining showed good biofilm formation for this strain and it was therefore chosen to be further investigated in regard to its biofilm forming ability. To evaluate its behaviour in different conditions commonly encountered in food processing environments, biofilm assays and growth studies were performed using common laboratory media under a range of temperatures (20 °C, 30 °C and 37 °C). Furthermore, the effects of incubation time and different environmental conditions including static, dynamic and anaerobic incubation on biofilm formation were investigated. Changes in the environmental conditions resulted in different biofilm phenotypes of L. monocytogenes 15G01. We demonstrated that increasing temperature and incubation time led to a higher biofilm mass and that dynamic incubation has little effect on biofilm formation at 37 °C but encourages biofilm formation at 30 °C. Biofilm production at 20 °C was minimal regardless of the medium used. We furthermore observed that anaerobic environment led to reduced biofilm mass at 30 °C for all tested media but not at 37 °C. Biofilm formation could not be narrowed down to one factor but was rather dependent on multiple factors with temperature and medium having the biggest effects.
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Affiliation(s)
- Jessika Nowak
- The New Zealand Institute for Plant & Food Research Limited, Mt Albert, Auckland, New Zealand; Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
| | - Cristina D Cruz
- The New Zealand Institute for Plant & Food Research Limited, Mt Albert, Auckland, New Zealand
| | - Jon Palmer
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Graham C Fletcher
- The New Zealand Institute for Plant & Food Research Limited, Mt Albert, Auckland, New Zealand
| | - Steve Flint
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
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Whiteley AT, Pollock AJ, Portnoy DA. The PAMP c-di-AMP Is Essential for Listeria monocytogenes Growth in Rich but Not Minimal Media due to a Toxic Increase in (p)ppGpp. [corrected]. Cell Host Microbe 2015; 17:788-98. [PMID: 26028365 PMCID: PMC4469362 DOI: 10.1016/j.chom.2015.05.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/05/2015] [Accepted: 03/31/2015] [Indexed: 12/20/2022]
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a widely distributed second messenger that appears to be essential in multiple bacterial species, including the Gram-positive facultative intracellular pathogen Listeria monocytogenes. In this study, the only L. monocytogenes diadenylate cyclase gene, dacA, was deleted using a Cre-lox system activated during infection of cultured macrophages. All ΔdacA strains recovered from infected cells harbored one or more suppressor mutations that allowed growth in the absence of c-di-AMP. Suppressor mutations in the synthase domain of the bi-functional (p)ppGpp synthase/hydrolase led to reduced (p)ppGpp levels. A genetic assay confirmed that dacA was essential in wild-type but not strains lacking all three (p)ppGpp synthases. Further genetic analysis suggested that c-di-AMP was essential because accumulated (p)ppGpp altered GTP concentrations, thereby inactivating the pleiotropic transcriptional regulator CodY. We propose that c-di-AMP is conditionally essential for metabolic changes that occur in growth in rich medium and host cells but not minimal medium.
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Affiliation(s)
- Aaron T Whiteley
- Graduate Group in Infectious Diseases and Immunity, School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Alex J Pollock
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel A Portnoy
- Graduate Group in Infectious Diseases and Immunity, School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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50
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A duplex qPCR for the simultaneous detection of Escherichia coli O157:H7
and Listeria monocytogenes
using LNA probes. Lett Appl Microbiol 2015; 61:20-7. [DOI: 10.1111/lam.12427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/01/2015] [Accepted: 04/01/2015] [Indexed: 12/01/2022]
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