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Fang X, Yang Y, Guo Q, Zhang Y, Yuan M, Liang X, Liu J, Fang S, Fang C. Two-component system LiaSR negatively regulated the acid resistance and pathogenicity of Listeria monocytogenes 10403S. Food Microbiol 2024; 119:104428. [PMID: 38225058 DOI: 10.1016/j.fm.2023.104428] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 11/10/2023] [Accepted: 11/17/2023] [Indexed: 01/17/2024]
Abstract
The glutamate decarboxylase (GAD) system is one of the acid-resistant systems of Listeria monocytogenes (L. monocytogenes), while the regulatory mechanism of GadT2/GadD2, which plays the major role in the GAD system for acid resistance, is not clear. The two-component system (TCS) is a signal transduction system that is also involved in regulating acid resistance in bacteria. By screening the TCSs of L. monocytogenes 10403S, we found that knocking out the TCS LisSR (encoded by lmo1021/lmo1022) led to a significant increase in the transcription and expression of the gadT2/gadD2 cluster. Subsequently, we constructed a complemental strain CΔliaSR. and a complemental strain with LiaS His157 to Ala, which was designated as CΔliaSRH157A. Survival assay, transcriptional and expression analysis and pathogenicity assay revealed that liaSR deletion significantly enhanced the acid resistance and pathogenicity of 10403S and significantly increased the gadT2/gadD2 transcription and expression. Mutating LiaS His157 to Ala significantly enhanced the acid resistance and pathogenicity of CΔliaSR and significantly increased the gadT2/gadD2 transcription and expression. The results suggest that the two-component system LiaSR mediates the acid resistance and pathogenicity in 10403S by inhibiting the gadT2/gadD2 cluster, and the key activation site of LiaS is His157. This study provides novel knowledge on the regulation of GAD system and the control of this foodborne pathogen.
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Affiliation(s)
- Xiaowei Fang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China; College of Agriculture, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Yuying Yang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Qian Guo
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Yu Zhang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Mei Yuan
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Xiongyan Liang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Jing Liu
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Shouguo Fang
- College of Agriculture, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China.
| | - Chun Fang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China.
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2
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Wu J, McAuliffe O, O'Byrne CP. A novel RofA-family transcriptional regulator, GadR, controls the development of acid resistance in Listeria monocytogenes. mBio 2023; 14:e0171623. [PMID: 37882515 PMCID: PMC10746197 DOI: 10.1128/mbio.01716-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The ability to survive the acidic conditions found in the stomach is crucial for the food-borne pathogen Listeria monocytogenes to gain access to the mammalian gastrointestinal tract. Little is currently known about how acid resistance is regulated in this pathogen and why this trait is highly variable between strains. Here, we used comparative genomics to identify a novel RofA-family transcriptional regulator, GadR, that controls the development of acid resistance. The RofA family of regulators was previously found only in a small group of bacterial pathogens, including streptococci, where they regulate virulence properties. We show that gadR encodes the dominant regulator of acid resistance in L. monocytogenes and that its sequence variability accounts for previously observed differences between strains in this trait. Together, these findings significantly advance our understanding of how this important pathogen copes with acid stress and suggest a potential molecular target to aid its control in the food chain.
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Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Olivia McAuliffe
- Department of Food Biosciences, Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Conor P. O'Byrne
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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3
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Chowdhury B, Anand S. Environmental persistence of Listeria monocytogenes and its implications in dairy processing plants. Compr Rev Food Sci Food Saf 2023; 22:4573-4599. [PMID: 37680027 DOI: 10.1111/1541-4337.13234] [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: 01/25/2023] [Revised: 07/10/2023] [Accepted: 08/09/2023] [Indexed: 09/09/2023]
Abstract
Listeriosis, an invasive illness with a fatality rate between 20% and 30%, is caused by the ubiquitous bacterium Listeria monocytogenes. Human listeriosis has long been associated with foods. This is because the ubiquitous nature of the bacteria renders it a common food contaminant, posing a significant risk to the food processing sector. Although several sophisticated stress coping mechanisms have been identified as significant contributing factors toward the pathogen's persistence, a complete understanding of the mechanisms underlying persistence across various strains remains limited. Moreover, aside from genetic aspects that promote the ability to cope with stress, various environmental factors that exist in food manufacturing plants could also contribute to the persistence of the pathogen. The objective of this review is to provide insight into the challenges faced by the dairy industry because of the pathogens' environmental persistence. Additionally, it also aims to emphasize the diverse adaptation and response mechanisms utilized by L. monocytogenes in food manufacturing plants to evade environmental stressors. The persistence of L. monocytogenes in the food processing environment poses a serious threat to food safety and public health. The emergence of areas with high levels of L. monocytogenes contamination could facilitate Listeria transmission through aerosols, potentially leading to the recontamination of food, particularly from floors and drains, when sanitation is implemented alongside product manufacturing. Hence, to produce safe dairy products and reduce the frequency of outbreaks of listeriosis, it is crucial to understand the factors that contribute to the persistence of this pathogen and to implement efficient control strategies.
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Affiliation(s)
- Bhaswati Chowdhury
- Department of Dairy and Food Science, South Dakota State University, Brookings, South Dakota, USA
| | - Sanjeev Anand
- Department of Dairy and Food Science, South Dakota State University, Brookings, South Dakota, USA
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4
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Fang X, Zhang Y, Guo Q, Yuan M, Liang X, Liu J, Fang S, Yang Y, Fang C. GadR4 mediates the acid resistance and pathogenicity of Listeria monocytogenes 10403S by negatively regulating the gadT2/gadD2 cluster. Food Microbiol 2023; 112:104248. [PMID: 36906312 DOI: 10.1016/j.fm.2023.104248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 01/29/2023] [Accepted: 02/23/2023] [Indexed: 03/06/2023]
Abstract
Listeria monocytogenes is an important foodborne pathogen that can survive under acidic conditions. The glutamate decarboxylase (GAD) system is one of the acid resistance systems of L. monocytogenes. It usually comprises two glutamate transporters (GadT1/T2) and three glutamate decarboxylases (GadD1/D2/D3). Among them, gadT2/gadD2 contributes most significantly to the acid resistance of L. monocytogenes. However, the regulation mechanisms of gadT2/gadD2 still remain unclear. The results of this study indicated that gadT2/gadD2 deletion significantly decreases the survival rate of L. monocytogenes under different acidic conditions, including brain and heart infusion (BHI) broth, with a pH of 2.5, 2% citric acid, 2% acetic acid and 2% lactic acid. Further, gadT2/gadD2 cluster was expressed in the representative strains in response to alkaline stress rather than acid stress. To explore the regulation of gadT2/gadD2, we knocked out the five transcriptional factors belonging to the Rgg family in L. monocytogenes 10403S. We found that the deletion of gadR4, which exhibits the highest homology with the gadR of Lactococcus lactis, resulted in a significant increase in the survival rate of L. monocytogenes upon acid stress. Western blot analysis showed that gadR4 deletion significantly increased the gadD2 expression of L. monocytogenes under alkaline and neutral conditions. Furthermore, the gfp reporter gene showed that gadR4 deletion significantly increased the expression of the gadT2/gadD2 cluster. Adhesion and invasion assays indicated that gadR4 deletion significantly increased the rates of adhesion and invasion of L. monocytogenes to epithelial Caco-2 cells. Virulence assays showed that gadR4 knockout significantly improved the colonization ability of L. monocytogenes in the livers and spleens of the infected mice. Taken together, our results showed that GadR4, a transcription factor belonging to the Rgg family, negatively regulates the gadT2/gadD2 cluster, thus, reducing the acid stress tolerance and pathogenicity of L. monocytogens 10403S. Our results provide a better understanding of the regulation of the GAD system of L. monocytogenes and a novel approach to potentially prevent and control listeriosis.
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Affiliation(s)
- Xiaowei Fang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China; College of Agriculture, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Yu Zhang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Qian Guo
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Mei Yuan
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Xiongyan Liang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Jing Liu
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Shouguo Fang
- College of Agriculture, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Yuying Yang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China
| | - Chun Fang
- College of Animal Science, Yangtze University, No.88, Jingmi Road, Jingzhou, 434025, China.
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Listeria monocytogenes-How This Pathogen Uses Its Virulence Mechanisms to Infect the Hosts. Pathogens 2022; 11:pathogens11121491. [PMID: 36558825 PMCID: PMC9783847 DOI: 10.3390/pathogens11121491] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/23/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Listeriosis is a serious food-borne illness, especially in susceptible populations, including children, pregnant women, and elderlies. The disease can occur in two forms: non-invasive febrile gastroenteritis and severe invasive listeriosis with septicemia, meningoencephalitis, perinatal infections, and abortion. Expression of each symptom depends on various bacterial virulence factors, immunological status of the infected person, and the number of ingested bacteria. Internalins, mainly InlA and InlB, invasins (invasin A, LAP), and other surface adhesion proteins (InlP1, InlP4) are responsible for epithelial cell binding, whereas internalin C (InlC) and actin assembly-inducing protein (ActA) are involved in cell-to-cell bacterial spread. L. monocytogenes is able to disseminate through the blood and invade diverse host organs. In persons with impaired immunity, the elderly, and pregnant women, the pathogen can also cross the blood-brain and placental barriers, which results in the invasion of the central nervous system and fetus infection, respectively. The aim of this comprehensive review is to summarize the current knowledge on the epidemiology of listeriosis and L. monocytogenes virulence mechanisms that are involved in host infection, with a special focus on their molecular and cellular aspects. We believe that all this information is crucial for a better understanding of the pathogenesis of L. monocytogenes infection.
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6
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Schwarz J, Schumacher K, Brameyer S, Jung K. Bacterial battle against acidity. FEMS Microbiol Rev 2022; 46:6652135. [PMID: 35906711 DOI: 10.1093/femsre/fuac037] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 07/11/2022] [Accepted: 07/27/2022] [Indexed: 01/09/2023] Open
Abstract
The Earth is home to environments characterized by low pH, including the gastrointestinal tract of vertebrates and large areas of acidic soil. Most bacteria are neutralophiles, but can survive fluctuations in pH. Herein, we review how Escherichia, Salmonella, Helicobacter, Brucella, and other acid-resistant Gram-negative bacteria adapt to acidic environments. We discuss the constitutive and inducible defense mechanisms that promote survival, including proton-consuming or ammonia-producing processes, cellular remodeling affecting membranes and chaperones, and chemotaxis. We provide insights into how Gram-negative bacteria sense environmental acidity using membrane-integrated and cytosolic pH sensors. Finally, we address in more detail the powerful proton-consuming decarboxylase systems by examining the phylogeny of their regulatory components and their collective functionality in a population.
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Affiliation(s)
- Julia Schwarz
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
| | - Kilian Schumacher
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
| | - Sophie Brameyer
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
| | - Kirsten Jung
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
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7
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Sun Y, Mehmood A, Battino M, Xiao J, Chen X. Enrichment of Gamma-aminobutyric acid in foods: From conventional methods to innovative technologies. Food Res Int 2022; 162:111801. [DOI: 10.1016/j.foodres.2022.111801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/11/2022] [Accepted: 08/18/2022] [Indexed: 11/26/2022]
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8
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Sibanda T, Buys EM. Listeria monocytogenes Pathogenesis: The Role of Stress Adaptation. Microorganisms 2022; 10:microorganisms10081522. [PMID: 36013940 PMCID: PMC9416357 DOI: 10.3390/microorganisms10081522] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/08/2022] [Accepted: 07/19/2022] [Indexed: 12/13/2022] Open
Abstract
Adaptive stress tolerance responses are the driving force behind the survival ability of Listeria monocytogenes in different environmental niches, within foods, and ultimately, the ability to cause human infections. Although the bacterial stress adaptive responses are primarily a necessity for survival in foods and the environment, some aspects of the stress responses are linked to bacterial pathogenesis. Food stress-induced adaptive tolerance responses to acid and osmotic stresses can protect the pathogen against similar stresses in the gastrointestinal tract (GIT) and, thus, directly aid its virulence potential. Moreover, once in the GIT, the reprogramming of gene expression from the stress survival-related genes to virulence-related genes allows L. monocytogenes to switch from an avirulent to a virulent state. This transition is controlled by two overlapping and interlinked transcriptional networks for general stress response (regulated by Sigma factor B, (SigB)) and virulence (regulated by the positive regulatory factor A (PrfA)). This review explores the current knowledge on the molecular basis of the connection between stress tolerance responses and the pathogenesis of L. monocytogenes. The review gives a detailed background on the currently known mechanisms of pathogenesis and stress adaptation. Furthermore, the paper looks at the current literature and theories on the overlaps and connections between the regulatory networks for SigB and PrfA.
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Affiliation(s)
- Thulani Sibanda
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa;
- Department of Applied Biology and Biochemistry, National University of Science and Technology, Bulawayo P.O. Box AC939, Zimbabwe
| | - Elna M. Buys
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa;
- Correspondence:
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9
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Osek J, Lachtara B, Wieczorek K. Listeria monocytogenes - How This Pathogen Survives in Food-Production Environments? Front Microbiol 2022; 13:866462. [PMID: 35558128 PMCID: PMC9087598 DOI: 10.3389/fmicb.2022.866462] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/04/2022] [Indexed: 12/13/2022] Open
Abstract
The foodborne pathogen Listeria monocytogenes is the causative agent of human listeriosis, a severe disease, especially dangerous for the elderly, pregnant women, and newborns. Although this infection is comparatively rare, it is often associated with a significant mortality rate of 20-30% worldwide. Therefore, this microorganism has an important impact on food safety. L. monocytogenes can adapt, survive and even grow over a wide range of food production environmental stress conditions such as temperatures, low and high pH, high salt concentration, ultraviolet lights, presence of biocides and heavy metals. Furthermore, this bacterium is also able to form biofilm structures on a variety of surfaces in food production environments which makes it difficult to remove and allows it to persist for a long time. This increases the risk of contamination of food production facilities and finally foods. The present review focuses on the key issues related to the molecular mechanisms of the pathogen survival and adaptation to adverse environmental conditions. Knowledge and understanding of the L. monocytogenes adaptation approaches to environmental stress factors will have a significant influence on the development of new, efficient, and cost-effective methods of the pathogen control in the food industry, which is critical to ensure food production safety.
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Affiliation(s)
- Jacek Osek
- Department of Hygiene of Food of Animal Origin, National Veterinary Research Institute, Puławy, Poland
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10
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Yogeswara IBA, Maneerat S, Haltrich D. Glutamate Decarboxylase from Lactic Acid Bacteria-A Key Enzyme in GABA Synthesis. Microorganisms 2020; 8:microorganisms8121923. [PMID: 33287375 PMCID: PMC7761890 DOI: 10.3390/microorganisms8121923] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 01/05/2023] Open
Abstract
Glutamate decarboxylase (l-glutamate-1-carboxylase, GAD; EC 4.1.1.15) is a pyridoxal-5’-phosphate-dependent enzyme that catalyzes the irreversible α-decarboxylation of l-glutamic acid to γ-aminobutyric acid (GABA) and CO2. The enzyme is widely distributed in eukaryotes as well as prokaryotes, where it—together with its reaction product GABA—fulfils very different physiological functions. The occurrence of gad genes encoding GAD has been shown for many microorganisms, and GABA-producing lactic acid bacteria (LAB) have been a focus of research during recent years. A wide range of traditional foods produced by fermentation based on LAB offer the potential of providing new functional food products enriched with GABA that may offer certain health-benefits. Different GAD enzymes and genes from several strains of LAB have been isolated and characterized recently. GABA-producing LAB, the biochemical properties of their GAD enzymes, and possible applications are reviewed here.
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Affiliation(s)
- Ida Bagus Agung Yogeswara
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences BOKU, Muthgasse 18, 1190 Vienna, Austria;
- Nutrition Department, Faculty of Health, Science and Technology, Universitas Dhyana Pura, Dalung Kuta utara 80361, Bali, Indonesia
- Correspondence:
| | - Suppasil Maneerat
- Faculty of Agro-Industry, Prince of Songkla University, Hat Yai 90110, Songkhla, Thailand;
| | - Dietmar Haltrich
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences BOKU, Muthgasse 18, 1190 Vienna, Austria;
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11
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Guerreiro DN, Arcari T, O'Byrne CP. The σ B-Mediated General Stress Response of Listeria monocytogenes: Life and Death Decision Making in a Pathogen. Front Microbiol 2020; 11:1505. [PMID: 32733414 PMCID: PMC7358398 DOI: 10.3389/fmicb.2020.01505] [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: 04/28/2020] [Accepted: 06/10/2020] [Indexed: 12/17/2022] Open
Abstract
Sensing and responding to environmental cues is critical for the adaptability and success of the food-borne bacterial pathogen Listeria monocytogenes. A supramolecular multi-protein complex known as the stressosome, which acts as a stress sensing hub, is responsible for orchestrating the activation of a signal transduction pathway resulting in the activation of σB, the sigma factor that controls the general stress response (GSR). When σB is released from the anti-sigma factor RsbW, a rapid up-regulation of the large σB regulon, comprised of ≥ 300 genes, ensures that cells respond appropriately to the new environmental conditions. A diversity of stresses including low pH, high osmolarity, and blue light are known to be sensed by the stressosome, resulting in a generalized increase in stress resistance. Appropriate activation of the stressosome and deployment of σB are critical to fitness as there is a trade-off between growth and stress protection when the GSR is deployed. We review the recent developments in this field and describe an up-to-date model of how this sensory organelle might integrate environmental signals to produce an appropriate activation of the GSR. Some of the outstanding questions and challenges in this fascinating field are also discussed.
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Affiliation(s)
- Duarte N Guerreiro
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Talia Arcari
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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12
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Paudyal R, O'Byrne CP, Karatzas KA. Amino acids other than glutamate affect the expression of the GAD system in Listeria monocytogenes enhancing acid resistance. Food Microbiol 2020; 90:103481. [PMID: 32336364 DOI: 10.1016/j.fm.2020.103481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/23/2020] [Accepted: 02/28/2020] [Indexed: 01/06/2023]
Abstract
The Glutamate Decarboxylase (GAD) system is important for survival of L. monocytogenes and other microorganisms under acidic conditions. Environmental conditions influence the function of the GAD system. Until now, the only conditions known to lead to increased transcription of the GAD system are the stationary phase in rich media and anoxic conditions. Previously, we showed that transcription of the GAD system requires unidentified compounds other than glutamate present in rich media. Following a test looking at various compounds we identified for first time that peptone, tryptone and casamino acids activate the GAD system under oxic conditions suggesting that amino acid(s) other than glutamate and/or peptides are important for the above process. The defined medium, where the GAD system is inactive, once it is supplemented with the above compounds results in an active intracellular and extracellular GAD system and increased acid resistance. Through functional genomics we show that these compounds are required for GadD2 activity and although we previously showed that GadD3 is active part of the intracellular GAD system, the supplementation did not activate this gene. The above is explained by the fact that only gadD2 transcription was upregulated by these compounds while the transcription of gadD1 and gadD3 remained unaffected. Together our results show that the L. monocytogenes GadD2 decarboxylase is activated in the presence of amino acids or peptides other than glutamate, a finding that has important implications for acid tolerance and food safety.
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Affiliation(s)
- Ranju Paudyal
- Department of Food and Nutritional Sciences, The University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP, UK
| | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
| | - Kimon Andreas Karatzas
- Department of Food and Nutritional Sciences, The University of Reading, PO Box 226, Whiteknights, Reading, RG6 6AP, UK.
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13
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Henderson LO, Erazo Flores BJ, Skeens J, Kent D, Murphy SI, Wiedmann M, Guariglia-Oropeza V. Nevertheless, She Resisted - Role of the Environment on Listeria monocytogenes Sensitivity to Nisin Treatment in a Laboratory Cheese Model. Front Microbiol 2020; 11:635. [PMID: 32328054 PMCID: PMC7160321 DOI: 10.3389/fmicb.2020.00635] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/20/2020] [Indexed: 01/24/2023] Open
Abstract
The growth of Listeria monocytogenes on refrigerated, ready-to-eat food products is a major health and economic concern. The natural antimicrobial nisin targets the bacterial cell wall and can be used to inhibit L. monocytogenes growth on cheese. Cell wall composition and structure, and therefore the efficacy of cell wall acting control strategies, can be severely affected by environmental and stress conditions. The goal of this study was to determine the effect of a range of pH and temperatures on the efficacy of nisin against several strains of L. monocytogenes in a lab-scale, cheese model. Cheese was made with or without the addition of nisin at different pH and then inoculated with L. monocytogenes; L. monocytogenes numbers were quantified after 1, 7, and 14 days of incubation at 6, 14, or 22°C. While our data show that nisin treatment is able to reduce L. monocytogenes numbers, at least initially, growth of this pathogen can occur even in the presence of nisin, especially when cheese is stored at higher temperatures. Several environmental factors were found to affect nisin efficacy against L. monocytogenes. For example, nisin is more effective when cheese is stored at lower temperatures. Nisin is also more effective when cheese is made at higher pH (6 and 6.5), compared to cheese made at pH 5.5, and this effect is at least partially due to the activity of cell envelope modification genes dltA and mprF. Serotype was also found to affect nisin efficacy against L. monocytogenes; serotype 4b strains showed lower susceptibility to nisin treatment compared to serotype 1/2 strains. Overall, our results highlight the importance of considering environmental conditions specific to a food matrix when developing and applying nisin-based intervention strategies against L. monocytogenes.
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Affiliation(s)
- L. O. Henderson
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - B. J. Erazo Flores
- Department of Food Science, Cornell University, Ithaca, NY, United States
- Universidad de Puerto Rico, Mayagüez, Puerto Rico
| | - J. Skeens
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - D. Kent
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - S. I. Murphy
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - M. Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY, United States
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14
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Lee S, Lee H, Choi Y, Kim S, Lee J, Ha J, Oh H, Kim Y, Lee Y, Kim HJ, Yoon Y. Development of Kinetic Models and Their Applications to Describe the Resistance of Listeria monocytogenes in Napa Cabbage Kimchi to Fermentation Conditions. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2020. [DOI: 10.3136/fstr.26.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Soomin Lee
- Risk Analysis Research Center, Sookmyung Women's University
| | - Heeyoung Lee
- Food Standard Research Center, Korea Food Research Institute
| | - Yukyung Choi
- Department of Food and Nutrition, Sookmyung Women's University
| | - Sejeong Kim
- Department of Food and Nutrition, Sookmyung Women's University
| | - Jeeyeon Lee
- Department of Food and Nutrition, Sookmyung Women's University
| | - Jimyeong Ha
- Department of Food and Nutrition, Sookmyung Women's University
| | - Hyemin Oh
- Department of Food and Nutrition, Sookmyung Women's University
| | - Yujin Kim
- Department of Food and Nutrition, Sookmyung Women's University
| | - Yewon Lee
- Department of Food and Nutrition, Sookmyung Women's University
| | - Hyun Jung Kim
- Food Safety Research Division, Korea Food Research Institute
| | - Yohan Yoon
- Risk Analysis Research Center, Sookmyung Women's University
- Department of Food and Nutrition, Sookmyung Women's University
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15
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16
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Castelletto V, Barnes RH, Karatzas KA, Edwards-Gayle CJC, Greco F, Hamley IW, Seitsonen J, Ruokolainen J. Restructuring of Lipid Membranes by an Arginine-Capped Peptide Bolaamphiphile. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:1302-1311. [PMID: 30056711 DOI: 10.1021/acs.langmuir.8b01014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We study the self-assembly of arginine-capped bolaamphiphile peptide RA3R (A: alanine, R: arginine) together with its binding to model membranes and its cytotoxicity and antimicrobial activity. Anionic 2-oleoyl-1-palmitoyl- sn-glycero-3-phospho-rac-(1-glycerol) sodium salt/2-oleoyl-1-palmitoyl- sn-glycero-3-phosphoethanolamine (POPG/POPE) vesicles and zwitterionic 1,2-dioleoyl- sn-glycero-3-phosphocholine/2-oleoyl-1-palmitoyl- sn-glycero-3-phosphocholine (POPC/DOPC) vesicles are used as model membranes to mimic bacterial and mammalian cell membranes, respectively. We show that RA3R adopts a polyproline-II collagen-like conformation in water. Binding of RA3R to POPG/POPE vesicles induces a strong correlation between the lipid bilayers, driven by RA3R/POPG attractive electrostatic interaction together with a shift of the intramolecular POPE zwitterionic interaction toward an attractive electrostatic interaction with the RA3R. Populations of RA3R/POPG/POPE vesicles comprise different bilayer spacings, dA and dB, controlled by the conformation of the lipid chains corresponding to the Lβ (gel-like) and Lα (liquid-crystal) phases, respectively. Cryo-TEM images reveal the presence of vesicles with no internal structure, compartmentalized thin-wall vesicles, or multilayer vesicles with uncorrelated layers and compartmentalization depending on the RA3R/POPG/POPE composition. In contrast, the interaction of RA3R with multilamellar POPC/DOPC vesicles leads to the decorrelation of the lipid bilayers. RA3R was tolerated by skin fibroblast cells for a concentration up to 0.01 wt %, while 0.25 wt % RA3R proved to be an efficient antibacterial agent against Gram-positive bacteria L. monocytogenes. Our results highlight the ability of RA3R to distinguish between bacterial and mammalian cells and establish this peptide as a candidate to reduce the proliferation of L. monocytogenes bacteria.
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Affiliation(s)
- Valeria Castelletto
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Ruth H Barnes
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Kimon-Andreas Karatzas
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Charlotte J C Edwards-Gayle
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Francesca Greco
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Ian W Hamley
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Jani Seitsonen
- Department of Applied Physics , Aalto School of Science , P.O. Box 15100, FI-00076 Aalto , Finland
| | - Janne Ruokolainen
- Department of Applied Physics , Aalto School of Science , P.O. Box 15100, FI-00076 Aalto , Finland
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17
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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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18
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Rodríguez-López P, Rodríguez-Herrera JJ, Vázquez-Sánchez D, López Cabo M. Current Knowledge on Listeria monocytogenes Biofilms in Food-Related Environments: Incidence, Resistance to Biocides, Ecology and Biocontrol. Foods 2018; 7:E85. [PMID: 29874801 PMCID: PMC6025129 DOI: 10.3390/foods7060085] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/16/2022] Open
Abstract
Although many efforts have been made to control Listeria monocytogenes in the food industry, growing pervasiveness amongst the population over the last decades has made this bacterium considered to be one of the most hazardous foodborne pathogens. Its outstanding biocide tolerance capacity and ability to promiscuously associate with other bacterial species forming multispecies communities have permitted this microorganism to survive and persist within the industrial environment. This review is designed to give the reader an overall picture of the current state-of-the-art in L. monocytogenes sessile communities in terms of food safety and legislation, ecological aspects and biocontrol strategies.
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Affiliation(s)
- Pedro Rodríguez-López
- Department of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), 6, Eduardo Cabello, 36208 Vigo, Spain.
| | - Juan José Rodríguez-Herrera
- Department of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), 6, Eduardo Cabello, 36208 Vigo, Spain.
| | - Daniel Vázquez-Sánchez
- "Luiz de Queiroz" College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900 São Paulo, Brazil.
| | - Marta López Cabo
- Department of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), 6, Eduardo Cabello, 36208 Vigo, Spain.
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19
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Wang Q, Liu X, Fu J, Wang S, Chen Y, Chang K, Li H. Substrate sustained release-based high efficacy biosynthesis of GABA by Lactobacillus brevis NCL912. Microb Cell Fact 2018; 17:80. [PMID: 29778094 PMCID: PMC5960080 DOI: 10.1186/s12934-018-0919-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/04/2018] [Indexed: 12/30/2022] Open
Abstract
Background Gamma-aminobutyric acid (GABA) plays a significant role in the food and drug industries. Our previous study established an efficient fed-batch fermentation process for Lactobacillus brevis NCL912 production of GABA from monosodium l-glutamate; however, monosodium l-glutamate may not be an ideal substrate, as it can result in the rapid increase of pH due to decarboxylation. Thus, in this study, l-glutamic acid was proposed as a substrate. To evaluate its potential, key components of the fermentation medium affecting GABA synthesis were re-screened and re-optimized to enhance GABA production from L. brevis NCL912. Results The initial fermentation medium (pH 3.3) used for optimization was: 50 g/L glucose, 25 g/L yeast extract, 10 mg/L manganese sulfate (MnSO4·H2O), 2 g/L Tween-80, and 220 g/L l-glutamic acid. Glucose, a nitrogen source, magnesium, and Tween-80 had notable effects on GABA production from the l-glutamic acid-based process; other factors showed no or marginal effects. The optimized levels of the four key components in the fermentation medium were 25 g/L glucose, 25 g/L yeast extract FM408, 25 mg/L MnSO4·H2O, and 2 g/L Tween-80. A simple and efficient fermentation process for the bioconversion of GABA by L. brevis NCL912 was subsequently developed in a 10 L fermenter as follows: fermentation medium, 5 L; glutamic acid, 295 g/L; inoculum, 10% (v/v); incubation temperature, 32 °C; and agitation, 100 rpm. After 48 h of fermentation, the final GABA concentration increased up to 205.8 ± 8.0 g/L. Conclusions l-Glutamic acid was superior to monosodium l-glutamate as a substrate in the bioproduction of GABA. Thus, a high efficacy bioprocess with 205 g/L GABA for L. brevis NCL912 was established. This strategy may provide an alternative for increasing the bioconversion of GABA.
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Affiliation(s)
- Qiong Wang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China.,Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Xiaohua Liu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China.,Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Jinheng Fu
- Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Shuixing Wang
- Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Yuanhong Chen
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China.,Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Kunpeng Chang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China.,Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Haixing Li
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China. .,Sino-German Joint Research Institute, Nanchang University, Nanchang, 330047, People's Republic of China.
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20
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Castelletto V, Barnes RH, Karatzas KA, Edwards-Gayle CJC, Greco F, Hamley IW, Rambo R, Seitsonen J, Ruokolainen J. Arginine-Containing Surfactant-Like Peptides: Interaction with Lipid Membranes and Antimicrobial Activity. Biomacromolecules 2018; 19:2782-2794. [PMID: 29738229 DOI: 10.1021/acs.biomac.8b00391] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The activity of antimicrobial peptides stems from their interaction with bacterial membranes, which are disrupted according to a number of proposed mechanisms. Here, we investigate the interaction of a model antimicrobial peptide that contains a single arginine residue with vesicles containing model lipid membranes. The surfactant-like peptide Ala6-Arg (A6R) is studied in the form where both termini are capped (CONH-A6R-NH2, capA6R) or uncapped (NH2-A6R-OH, A6R). Lipid membranes are selected to correspond to model anionic membranes (POPE/POPG) resembling those in bacteria or model zwitterionic membranes (POPC/DOPC) similar to those found in mammalian cells. Viable antimicrobial agents should show activity against anionic membranes but not zwitterionic membranes. We find, using small-angle X-ray scattering (SAXS) and cryogenic-TEM (transmission electron microscopy) that, uniquely, capA6R causes structuring of anionic membranes due to the incorporation of the peptide in the lipid bilayer with peptide β-sheet conformation revealed by circular dichroism spectroscopy (CD). There is a preferential interaction of the peptide with POPG (which is the only anionic lipid in the systems studied) due to electrostatic interactions and bidentate hydrogen bonding between arginine guanidinium and lipid phosphate groups. At a certain composition, this peptide leads to the remarkable tubulation of zwitterionic phosphatidylcholine (PC) vesicles, which is ascribed to the interaction of the peptide with the outer lipid membrane, which occurs without penetration into the membrane. In contrast, peptide A6R has a minimal influence on the anionic lipid membranes (and no β-sheet peptide structure is observed) but causes thinning (lamellar decorrelation) of zwitterionic membranes. We also investigated the cytotoxicity (to fibroblasts) and antimicrobial activity of these two peptides against model Gram positive and Gram negative bacteria. A strong selective antimicrobial activity against Gram positive Listeria monocytogenes, which is an important food-borne pathogen, is observed for capA6R. Peptide A6R is active against all three studied bacteria. The activity of the peptides against bacteria and mammalian cells is related to the specific interactions uncovered through our SAXS, cryo-TEM, and CD measurements. Our results highlight the exquisite sensitivity to the charge distribution in these designed peptides and its effect on the interaction with lipid membranes bearing different charges, and ultimately on antimicrobial activity.
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Affiliation(s)
- Valeria Castelletto
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Ruth H Barnes
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Kimon-Andreas Karatzas
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Charlotte J C Edwards-Gayle
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Francesca Greco
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Ian W Hamley
- School of Chemistry, Food Biosciences and Pharmacy , University of Reading , Whiteknights , Reading RG6 6AD , United Kingdom
| | - Robert Rambo
- Diamond Light Source , Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE , United Kingdom
| | - Jani Seitsonen
- Department of Applied Physics , Aalto School of Science , P.O. Box 15100, FI-00076 Aalto , Finland
| | - Janne Ruokolainen
- Department of Applied Physics , Aalto School of Science , P.O. Box 15100, FI-00076 Aalto , Finland
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21
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Paudyal R, Barnes RH, Karatzas KAG. A novel approach in acidic disinfection through inhibition of acid resistance mechanisms; Maleic acid-mediated inhibition of glutamate decarboxylase activity enhances acid sensitivity of Listeria monocytogenes. Food Microbiol 2018; 69:96-104. [DOI: 10.1016/j.fm.2017.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 01/23/2023]
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22
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Ricci A, Allende A, Bolton D, Chemaly M, Davies R, Fernández Escámez PS, Girones R, Herman L, Koutsoumanis K, Nørrung B, Robertson L, Ru G, Sanaa M, Simmons M, Skandamis P, Snary E, Speybroeck N, Ter Kuile B, Threlfall J, Wahlström H, Takkinen J, Wagner M, Arcella D, Da Silva Felicio MT, Georgiadis M, Messens W, Lindqvist R. Listeria monocytogenes contamination of ready-to-eat foods and the risk for human health in the EU. EFSA J 2018; 16:e05134. [PMID: 32760461 PMCID: PMC7391409 DOI: 10.2903/j.efsa.2018.5134] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Food safety criteria for Listeria monocytogenes in ready-to-eat (RTE) foods have been applied from 2006 onwards (Commission Regulation (EC) 2073/2005). Still, human invasive listeriosis was reported to increase over the period 2009-2013 in the European Union and European Economic Area (EU/EEA). Time series analysis for the 2008-2015 period in the EU/EEA indicated an increasing trend of the monthly notified incidence rate of confirmed human invasive listeriosis of the over 75 age groups and female age group between 25 and 44 years old (probably related to pregnancies). A conceptual model was used to identify factors in the food chain as potential drivers for L. monocytogenes contamination of RTE foods and listeriosis. Factors were related to the host (i. population size of the elderly and/or susceptible people; ii. underlying condition rate), the food (iii. L. monocytogenes prevalence in RTE food at retail; iv. L. monocytogenes concentration in RTE food at retail; v. storage conditions after retail; vi. consumption), the national surveillance systems (vii. improved surveillance), and/or the bacterium (viii. virulence). Factors considered likely to be responsible for the increasing trend in cases are the increased population size of the elderly and susceptible population except for the 25-44 female age group. For the increased incidence rates and cases, the likely factor is the increased proportion of susceptible persons in the age groups over 45 years old for both genders. Quantitative modelling suggests that more than 90% of invasive listeriosis is caused by ingestion of RTE food containing > 2,000 colony forming units (CFU)/g, and that one-third of cases are due to growth in the consumer phase. Awareness should be increased among stakeholders, especially in relation to susceptible risk groups. Innovative methodologies including whole genome sequencing (WGS) for strain identification and monitoring of trends are recommended.
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23
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Castelletto V, Kaur A, Hamley I, Barnes RH, Karatzas KA, Hermida-Merino D, Swioklo S, Connon CJ, Stasiak J, Reza M, Ruokolainen J. Hybrid membrane biomaterials from self-assembly in polysaccharide and peptide amphiphile mixtures: controllable structural and mechanical properties and antimicrobial activity. RSC Adv 2017. [DOI: 10.1039/c6ra27244d] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Macroscopic capsules, with tunable properties based on hierarchical self-assembly on multiple lengthscales, are prepared from the co-operative self-assembly of polysaccharide and peptide amphiphiles.
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Affiliation(s)
- V. Castelletto
- School of Chemistry, Pharmacy and Food Biosciences
- University of Reading
- Reading RG6 6AD
- UK
| | - A. Kaur
- School of Chemistry, Pharmacy and Food Biosciences
- University of Reading
- Reading RG6 6AD
- UK
| | - I. W. Hamley
- School of Chemistry, Pharmacy and Food Biosciences
- University of Reading
- Reading RG6 6AD
- UK
| | - R. H. Barnes
- School of Chemistry, Pharmacy and Food Biosciences
- University of Reading
- Reading RG6 6AD
- UK
| | - K.-A. Karatzas
- School of Chemistry, Pharmacy and Food Biosciences
- University of Reading
- Reading RG6 6AD
- UK
| | | | - S. Swioklo
- Institute of Genetic Medicine
- Newcastle University
- International Centre for Life
- Newcastle upon Tyne NE1 3BZ
- UK
| | - C. J. Connon
- Institute of Genetic Medicine
- Newcastle University
- International Centre for Life
- Newcastle upon Tyne NE1 3BZ
- UK
| | - J. Stasiak
- Department of Chemical Engineering and Biotechnology
- Cambridge CB2 3RA
- UK
| | - M. Reza
- Department of Applied Physics
- Aalto University School of Science
- FI-00076 Aalto
- Finland
| | - J. Ruokolainen
- Department of Applied Physics
- Aalto University School of Science
- FI-00076 Aalto
- Finland
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24
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Lim SY, Yap KP, Thong KL. Comparative genomics analyses revealed two virulent Listeria monocytogenes strains isolated from ready-to-eat food. Gut Pathog 2016; 8:65. [PMID: 27999619 PMCID: PMC5153821 DOI: 10.1186/s13099-016-0147-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/03/2016] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Listeria monocytogenes is an important foodborne pathogen that causes considerable morbidity in humans with high mortality rates. In this study, we have sequenced the genomes and performed comparative genomics analyses on two strains, LM115 and LM41, isolated from ready-to-eat food in Malaysia. RESULTS The genome size of LM115 and LM41 was 2,959,041 and 2,963,111 bp, respectively. These two strains shared approximately 90% homologous genes. Comparative genomics and phylogenomic analyses revealed that LM115 and LM41 were more closely related to the reference strains F2365 and EGD-e, respectively. Our virulence profiling indicated a total of 31 virulence genes shared by both analysed strains. These shared genes included those that encode for internalins and L. monocytogenes pathogenicity island 1 (LIPI-1). Both the Malaysian L. monocytogenes strains also harboured several genes associated with stress tolerance to counter the adverse conditions. Seven antibiotic and efflux pump related genes which may confer resistance against lincomycin, erythromycin, fosfomycin, quinolone, tetracycline, and penicillin, and macrolides were identified in the genomes of both strains. CONCLUSIONS Whole genome sequencing and comparative genomics analyses revealed two virulent L. monocytogenes strains isolated from ready-to-eat foods in Malaysia. The identification of strains with pathogenic, persistent, and antibiotic resistant potentials from minimally processed food warrant close attention from both healthcare and food industry.
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Affiliation(s)
- Shu Yong Lim
- Faculty of Science, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kien-Pong Yap
- Faculty of Science, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- Faculty of Science, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
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25
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NicAogáin K, O’Byrne CP. The Role of Stress and Stress Adaptations in Determining the Fate of the Bacterial Pathogen Listeria monocytogenes in the Food Chain. Front Microbiol 2016; 7:1865. [PMID: 27933042 PMCID: PMC5120093 DOI: 10.3389/fmicb.2016.01865] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/04/2016] [Indexed: 12/15/2022] Open
Abstract
The foodborne pathogen Listeria monocytogenes is a highly adaptable organism that can persist in a wide range of environmental and food-related niches. The consumption of contaminated ready-to-eat foods can cause infections, termed listeriosis, in vulnerable humans, particularly those with weakened immune systems. Although these infections are comparatively rare they are associated with high mortality rates and therefore this pathogen has a significant impact on food safety. L. monocytogenes can adapt to and survive a wide range of stress conditions including low pH, low water activity, and low temperature, which makes it problematic for food producers who rely on these stresses for preservation. Stress tolerance in L. monocytogenes can be explained partially by the presence of the general stress response (GSR), a transcriptional response under the control of the alternative sigma factor sigma B (σB) that reconfigures gene transcription to provide homeostatic and protective functions to cope with the stress. Within the host σB also plays a key role in surviving the harsh conditions found in the gastrointestinal tract. As the infection progresses beyond the GI tract L. monocytogenes uses an intracellular infectious cycle to propagate, spread and remain protected from the host's humoral immunity. Many of the virulence genes that facilitate this infectious cycle are under the control of a master transcriptional regulator called PrfA. In this review we consider the environmental reservoirs that enable L. monocytogenes to gain access to the food chain and discuss the stresses that the pathogen must overcome to survive and grow in these environments. The overlap that exists between stress tolerance and virulence is described. We review the principal measures that are used to control the pathogen and point to exciting new approaches that might provide improved means of control in the future.
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Affiliation(s)
| | - Conor P. O’Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, College of Science, National University of IrelandGalway, Ireland
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26
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Abee T, Koomen J, Metselaar K, Zwietering M, den Besten H. Impact of Pathogen Population Heterogeneity and Stress-Resistant Variants on Food Safety. Annu Rev Food Sci Technol 2016; 7:439-56. [DOI: 10.1146/annurev-food-041715-033128] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- T. Abee
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands;
| | - J. Koomen
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands;
| | - K.I. Metselaar
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands;
| | - M.H. Zwietering
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands;
| | - H.M.W. den Besten
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands;
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27
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Abstract
The dramatic rise in the incidence of antibiotic resistance demands that new therapeutic options will have to be developed. One potentially interesting class of antimicrobials are the modified bacteriocins termed lantibiotics, which are bacterially produced, posttranslationally modified, lanthionine/methyllanthionine-containing peptides. It is interesting that low levels of resistance have been reported for lantibiotics compared with commercial antibiotics. Given that there are very few examples of naturally occurring lantibiotic resistance, attempts have been made to deliberately induce resistance phenotypes in order to investigate this phenomenon. Mechanisms that hinder the action of lantibiotics are often innate systems that react to the presence of any cationic peptides/proteins or ones which result from cell well damage, rather than being lantibiotic specific. Such resistance mechanisms often arise due to altered gene regulation following detection of antimicrobials/cell wall damage by sensory proteins at the membrane. This facilitates alterations to the cell wall or changes in the composition of the membrane. Other general forms of resistance include the formation of spores or biofilms, which are a common mechanistic response to many classes of antimicrobials. In rare cases, bacteria have been shown to possess specific antilantibiotic mechanisms. These are often species specific and include the nisin lytic protein nisinase and the phenomenon of immune mimicry.
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Affiliation(s)
- Lorraine A Draper
- School of Microbiology, University College Cork, Cork, Ireland Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Paul D Cotter
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland
| | - Colin Hill
- School of Microbiology, University College Cork, Cork, Ireland Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - R Paul Ross
- School of Microbiology, University College Cork, Cork, Ireland Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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Metselaar KI, den Besten HMW, Boekhorst J, van Hijum SAFT, Zwietering MH, Abee T. Diversity of acid stress resistant variants of Listeria monocytogenes and the potential role of ribosomal protein S21 encoded by rpsU. Front Microbiol 2015; 6:422. [PMID: 26005439 PMCID: PMC4424878 DOI: 10.3389/fmicb.2015.00422] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 04/21/2015] [Indexed: 12/02/2022] Open
Abstract
The dynamic response of microorganisms to environmental conditions depends on the behavior of individual cells within the population. Adverse environments can select for stable stress resistant subpopulations. In this study, we aimed to get more insight in the diversity within Listeria monocytogenes LO28 populations, and the genetic basis for the increased resistance of stable resistant fractions isolated after acid exposure. Phenotypic cluster analysis of 23 variants resulted in three clusters and four individual variants and revealed multiple-stress resistance, with both unique and overlapping features related to stress resistance, growth, motility, biofilm formation, and virulence indicators. A higher glutamate decarboxylase activity correlated with increased acid resistance. Whole genome sequencing revealed mutations in rpsU, encoding ribosomal protein S21 in the largest phenotypic cluster, while mutations in ctsR, which were previously shown to be responsible for increased resistance of heat and high hydrostatic pressure resistant variants, were not found in the acid resistant variants. This underlined that large population diversity exists within one L. monocytogenes strain and that different adverse conditions drive selection for different variants. The finding that acid stress selects for rpsU variants provides potential insights in the mechanisms underlying population diversity of L. monocytogenes.
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Affiliation(s)
- Karin I Metselaar
- Top Institute Food and Nutrition Wageningen, Netherlands ; Laboratory of Food Microbiology, Wageningen University Wageningen, Netherlands
| | | | - Jos Boekhorst
- Top Institute Food and Nutrition Wageningen, Netherlands ; NIZO Food Research Ede, Netherlands
| | - Sacha A F T van Hijum
- Top Institute Food and Nutrition Wageningen, Netherlands ; NIZO Food Research Ede, Netherlands ; Bacterial Genomics Group, CMBI Centre for Molecular and Biomolecular Informatics, Radboud University Medical Center Nijmegen, Netherlands
| | - Marcel H Zwietering
- Top Institute Food and Nutrition Wageningen, Netherlands ; Laboratory of Food Microbiology, Wageningen University Wageningen, Netherlands
| | - Tjakko Abee
- Top Institute Food and Nutrition Wageningen, Netherlands ; Laboratory of Food Microbiology, Wageningen University Wageningen, Netherlands
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Bjornsdottir-Butler K, Green DP, Bolton GE, McClellan-Green PD. Control of Histamine-Producing Bacteria and Histamine Formation in Fish Muscle by Trisodium Phosphate. J Food Sci 2015; 80:M1253-8. [DOI: 10.1111/1750-3841.12875] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/12/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Kristin Bjornsdottir-Butler
- Dept. of Food; Bioprocessing and Nutrition Sciences North Carolina State Univ. Center of Marine Sciences and Technology; 303 College Circle Morehead City NC 28557 U.S.A
| | - David P. Green
- Dept. of Food; Bioprocessing and Nutrition Sciences North Carolina State Univ. Center of Marine Sciences and Technology; 303 College Circle Morehead City NC 28557 U.S.A
| | - Greg E. Bolton
- Dept. of Food; Bioprocessing and Nutrition Sciences North Carolina State Univ. Center of Marine Sciences and Technology; 303 College Circle Morehead City NC 28557 U.S.A
| | - Patricia D. McClellan-Green
- Dept. of Environmental and Molecular Toxicology; North Carolina State Univ. Center for Marine Sciences and Technology; 303 College Circle Morehead City NC 28557 U.S.A
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Barel M, Ramond E, Gesbert G, Charbit A. The complex amino acid diet of Francisella in infected macrophages. Front Cell Infect Microbiol 2015; 5:9. [PMID: 25705612 PMCID: PMC4319460 DOI: 10.3389/fcimb.2015.00009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/14/2015] [Indexed: 12/16/2022] Open
Abstract
Francisella tularensis, the agent of the zoonotic disease tularemia, is a highly infectious bacterium for a large number of animal species and can be transmitted to humans by various means. The bacterium is able to infect a variety of cell types but replicates in mammalian hosts mainly in the cytosol of infected macrophages. In order to resist the stressful and nutrient-restricted intracellular environments, it encounters during its systemic dissemination, Francisella has developed dedicated stress resistance mechanisms and adapted its metabolic and nutritional needs. Recent data form our laboratory and from several other groups have shown that Francisella simultaneously relies on multiple host amino acid sources during its intracellular life cycle. This review will summarize how intracellular Francisella use different amino acid sources, and their role in phagosomal escape and/or cytosolic multiplication and systemic dissemination. We will first summarize the data that we have obtained on two amino acid transporters involved in Francisella phagosomal escape and cytosolic multiplication i.e., the glutamate transporter GadC and the asparagine transporter AnsP, respectively. The specific contribution of glutamate and asparagine to the physiology of the bacterium will be evoked. Then, we will discuss how Francisella has adapted to obtain and utilize host amino acid resources, and notably the contribution of host transporters and autophagy process in the establishment of a nutrient-replete intracellular niche.
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Affiliation(s)
- Monique Barel
- Université Paris Descartes, Sorbonne Paris Cité Paris, France ; INSERM U1151 - Centre National de la Recherche Scientifique UMR 8253, Institut Necker-Enfants Malades Paris, France
| | - Elodie Ramond
- Université Paris Descartes, Sorbonne Paris Cité Paris, France ; INSERM U1151 - Centre National de la Recherche Scientifique UMR 8253, Institut Necker-Enfants Malades Paris, France
| | - Gael Gesbert
- Université Paris Descartes, Sorbonne Paris Cité Paris, France ; INSERM U1151 - Centre National de la Recherche Scientifique UMR 8253, Institut Necker-Enfants Malades Paris, France
| | - Alain Charbit
- Université Paris Descartes, Sorbonne Paris Cité Paris, France ; INSERM U1151 - Centre National de la Recherche Scientifique UMR 8253, Institut Necker-Enfants Malades Paris, France
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31
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Cheng C, Yang Y, Dong Z, Wang X, Fang C, Yang M, Sun J, Xiao L, Fang W, Song H. Listeria monocytogenes varies among strains to maintain intracellular pH homeostasis under stresses by different acids as analyzed by a high-throughput microplate-based fluorometry. Front Microbiol 2015; 6:15. [PMID: 25667585 PMCID: PMC4304241 DOI: 10.3389/fmicb.2015.00015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/07/2015] [Indexed: 11/16/2022] Open
Abstract
Listeria monocytogenes, a food-borne pathogen, has the capacity to maintain intracellular pH (pHi) homeostasis in acidic environments, but the underlying mechanisms remain elusive. Here, we report a simple microplate-based fluorescent method to determine pHi of listerial cells that were prelabeled with the fluorescent dye carboxyfluorescein diacetate N-succinimidyl ester and subjected to acid stress. We found that L. monocytogenes responds differently among strains toward organic and inorganic acids to maintain pHi homeostasis. The capacity of L. monocytogenes to maintain pHi at extracellular pH 4.5 (pHex) was compromised in the presence of acetic acid and lactic acid, but not by hydrochloric acid and citric acid. Organic acids exhibited more inhibitory effects than hydrochloric acid at certain pH conditions. Furthermore, the virulent stains L. monocytogenes EGDe, 850658 and 10403S was more resistant to acidic stress than the avirulent M7 which showed a defect in maintaining pHi homeostasis. Deletion of sigB, a stress-responsive alternative sigma factor from 10403S, markedly altered intracellular pHi homeostasis, and showed a significant growth and survival defect under acidic conditions. Thus, this work provides new insights into bacterial survival mechanism to acidic stresses.
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Affiliation(s)
- Changyong Cheng
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Yongchun Yang
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Zhimei Dong
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Xiaowen Wang
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Chun Fang
- Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Zhejiang University Institute of Preventive Veterinary Medicine Hangzhou, China
| | - Menghua Yang
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Jing Sun
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Liya Xiao
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
| | - Weihuan Fang
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China ; Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Zhejiang University Institute of Preventive Veterinary Medicine Hangzhou, China
| | - Houhui Song
- College of Animal Science and Technology, Zhejiang A&F University Lin'an, China
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Metselaar KI, den Besten HM, Abee T, Moezelaar R, Zwietering MH. Isolation and quantification of highly acid resistant variants of Listeria monocytogenes. Int J Food Microbiol 2013; 166:508-14. [DOI: 10.1016/j.ijfoodmicro.2013.08.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/06/2013] [Accepted: 08/10/2013] [Indexed: 11/24/2022]
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Caballero Gómez N, Abriouel H, Ennahar S, Gálvez A. Comparative proteomic analysis of Listeria monocytogenes exposed to enterocin AS-48 in planktonic and sessile states. Int J Food Microbiol 2013; 167:202-7. [PMID: 24135676 DOI: 10.1016/j.ijfoodmicro.2013.08.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/25/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
Abstract
Enterocin AS-48 is a cyclic peptide of great interest for application in food preservation and sanitation. In the present study, the proteome response of Listeria monocytogenes to purified enterocin AS-48 was studied under two different conditions: planktonic cells and sessile cells grown on polystyrene plates. Ten different proteins were differentially expressed in planktonic L. monocytogenes cells treated with 0.1 μg/ml enterocin AS-48 compared to the untreated controls. Overexpressed proteins were related to stress response (DnaK) or carbohydrate transport and metabolism, while underexpressed and unexpressed proteins were related to metabolism (such as glyceraldehyde-3-phosphate dehydrogenase, pyruvate oxidase, glutamate dehydrogenase or glutamate decarboxylase) or stress (GroEL). In the sessile state, L. monocytogenes cells tolerated up to 10 μg/ml bacteriocin, and the treated biofilm cells overexpressed a set of 11 proteins, some of which could be related to stress response (DnaK, GroEL), protein synthesis and carbohydrate metabolism, while glyceraldehyde-3-phosphate dehydrogenase was the only unexpressed protein. Some of the overexpressed proteins (such as elongation factor Tu and GroEL) could also be implicated in cell adhesion. These results suggest different cell responses of L. monocytogenes to enterocin AS-48 in the planktonic and in the sessile state, including stress response and cell metabolism proteins. While in the planktonic state the bacterium may tend to compensate for the cytoplasmic cell permeability changes induced by AS-48 by reinforcing carbohydrate transport and metabolism, sessile cells seem to respond by shifting carbohydrate metabolism and reinforcing protein synthesis. Stress response proteins also seem to be important in the response to AS-48, but the stress response seems to be different in planktonic and in sessile cells.
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Affiliation(s)
- Natacha Caballero Gómez
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
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Cheng C, Chen J, Fang C, Xia Y, Shan Y, Liu Y, Wen G, Song H, Fang W. Listeria monocytogenes aguA1, but not aguA2, encodes a functional agmatine deiminase: biochemical characterization of its catalytic properties and roles in acid tolerance. J Biol Chem 2013; 288:26606-15. [PMID: 23918931 DOI: 10.1074/jbc.m113.477380] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Listeria monocytogenes is adaptable to low pH environments and therefore crosses the intestinal barrier to establish systemic infections. L. monocytogenes aguA1 and aguA2 encode putative agmatine deiminases (AgDIs) AguA1 and AguA2. Transcription of aguA1 and aguA2 was significantly induced at pH 5.0. Deletion of aguA1 significantly impaired its survival both in gastric fluid at pH 2.5 and in mouse stomach, whereas aguA2 deletion did not show significant defect of survival in gastric fluid. With agmatine as the sole substrate, AguA1 expressed in Escherichia coli was optimal at 25 °C and over a wide range of pH from 3.5 to 10.5. Recombinant AguA2 showed no deiminase activity. Site-directed mutagenesis revealed that all nine AguA1 mutants completely lost enzymatic activity. AguA2 acquired AgDI activity only when Cys-157 was mutated to glycine. AguA1 mutation at the same site, G157C, also inactivated the enzyme. Thus, we have discovered Gly-157 as a novel residue other than the known catalytic triad (Cys-His-Glu/Asp) in L. monocytogenes that is critical for enzyme activity. Of the two putative AgDIs, we conclude that only AguA1 functionally participates in the AgDI pathway and mediates acid tolerance in L. monocytogenes.
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Affiliation(s)
- Changyong Cheng
- From the Zhejiang University Institute of Preventive Veterinary Medicine, Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, and Key Laboratory of Molecular Animal Nutrition of the Ministry of Education, Hangzhou, Zhejiang 310058, China
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35
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Cheng C, Chen J, Shan Y, Fang C, Liu Y, Xia Y, Song H, Fang W. Listeria monocytogenes ArcA contributes to acid tolerance. J Med Microbiol 2013; 62:813-821. [PMID: 23518652 DOI: 10.1099/jmm.0.055145-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The foodborne pathogen Listeria monocytogenes is able to colonize the human and animal intestinal tracts and subsequently crosses the intestinal barrier, causing systemic infection. For successful establishment of infection, L. monocytogenes must survive and adapt to the low pH environment of the stomach. Gene sequence analysis indicates that lmo0043, an orthologue of arcA, encodes a protein containing conserved motifs and critical active amino acids characteristic of arginine deiminase that mediates an arginine deimination reaction. We attempted to characterize the role of ArcA in acid tolerance in vitro and in mice models. Transcription of arcA was significantly increased in L. monocytogenes culture subjected to acid stress at pH 4.8, as compared with that at pH 7.0. Deletion of arcA impaired growth of L. monocytogenes under mild acidic conditions at pH 5.5, and reduced its survival in synthetic human gastric fluid at pH 2.5 and in the murine stomach. Bacterial load in the spleen of mice intraperitoneally inoculated with an arcA deletion mutant was significantly lower than that of the wild-type strain. These phenotypic changes were recoverable by genetic complementation. Thus, we conclude that L. monocytogenes arcA not only mediates acid tolerance in vitro but also participates in gastric survival and virulence in mice.
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Affiliation(s)
- Changyong Cheng
- Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
| | - Jianshun Chen
- Zhejiang Aquatic Disease Prevention and Quarantine Center, 20 Yile Road, Hangzhou, Zhejiang 310012, PR China
| | - Ying Shan
- Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
| | - Chun Fang
- Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
| | - Yuan Liu
- Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
| | - Ye Xia
- Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
| | - Houhui Song
- Zhejiang A&F University College of Animal Science & Technology, Lin'an, Zhejiang 311300, PR China
| | - Weihuan Fang
- Zhejiang A&F University College of Animal Science & Technology, Lin'an, Zhejiang 311300, PR China.,Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China
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36
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Sun Y, O'Riordan MXD. Regulation of bacterial pathogenesis by intestinal short-chain Fatty acids. ADVANCES IN APPLIED MICROBIOLOGY 2013; 85:93-118. [PMID: 23942149 PMCID: PMC4029053 DOI: 10.1016/b978-0-12-407672-3.00003-4] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The human gut microbiota is inextricably linked to health and disease. One important function of the commensal organisms living in the intestine is to provide colonization resistance against invading enteric pathogens. Because of the complex nature of the interaction between the microbiota and its host, multiple mechanisms likely contribute to resistance. In this review, we dissect the biological role of short-chain fatty acids (SCFA), which are fermentation end products of the intestinal microbiota, in host-pathogen interactions. SCFA exert an extensive influence on host physiology through nutritional, regulatory, and immunomodulatory functions and can also affect bacterial fitness as a form of acid stress. Moreover, SCFA act as a signal for virulence gene regulation in common enteric pathogens. Taken together, these studies highlight the importance of the chemical environment where the biology of the host, the microbiota, and the pathogen intersects, which provides a basis for designing effective infection prevention and control.
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Affiliation(s)
- Yvonne Sun
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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Smith JL, Liu Y, Paoli GC. How does Listeria monocytogenes combat acid conditions? Can J Microbiol 2012; 59:141-52. [PMID: 23540331 DOI: 10.1139/cjm-2012-0392] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Listeria monocytogenes, a major foodborne pathogen, possesses a number of mechanisms that enable it to combat the challenges posed by acidic environments, such as that of acidic foods and the gastrointestinal tract. One mechanism employed by L. monocytogenes for survival at low pH is the adaptive acid tolerance response (ATR) in which a short adaptive period at a nonlethal pH induces metabolic changes that allow the organism to survive a lethal pH. Overcoming acid conditions by L. monocytogenes involves a variety of regulatory responses, including the LisRK 2-component regulatory system, the SOS response, components of the σ(B) regulon, changes in membrane fluidity, the F0F1-ATPase proton pump, and at least 2 enzymatic systems that regulate internal hydrogen ion concentration (glutamate decarboxylase and arginine deiminase). It is not clear if these mechanisms exert their protective effects separately or in concert, but it is probable that these mechanisms overlap. Studies using mutants indicate that the glutamate decarboxylase system can protect L. monocytogenes when the organism is present in acidic juices, yogurt, salad dressing, mayonnaise, and modified CO2 atmospheres. The glutamate decarboxylase system also has a role in protecting L. monocytogenes against the acidic environment of the stomach. There is a need to study other acid resistance mechanisms of L. monocytogenes to determine their effectiveness in protecting the organism in acidic foods or during transit through the acid stomach.
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Affiliation(s)
- James L Smith
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038-8598, USA.
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38
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De Biase D, Pennacchietti E. Glutamate decarboxylase-dependent acid resistance in orally acquired bacteria: function, distribution and biomedical implications of the gadBC operon. Mol Microbiol 2012; 86:770-86. [PMID: 22995042 DOI: 10.1111/mmi.12020] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2012] [Indexed: 02/06/2023]
Abstract
For successful colonization of the mammalian host, orally acquired bacteria must overcome the extreme acidic stress (pH < 2.5) encountered during transit through the host stomach. The glutamate-dependent acid resistance (GDAR) system is by far the most potent acid resistance system in commensal and pathogenic Escherichia coli, Shigella flexneri, Listeria monocytogenes and Lactococcus lactis. GDAR requires the activity of glutamate decarboxylase (GadB), an intracellular PLP-dependent enzyme which performs a proton-consuming decarboxylation reaction, and of the cognate antiporter (GadC), which performs the glutamatein /γ-aminobutyrateout (GABA) electrogenic antiport. Herein we review recent findings on the structural determinants responsible for pH-dependent intracellular activation of E. coli GadB and GadC. A survey of genomes of bacteria (pathogenic and non-pathogenic), having in common the ability to colonize or to transit through the host gut, shows that the gadB and gadC genes frequently lie next or near each other. This gene arrangement is likely to be important to ensure timely co-regulation of the decarboxylase and the antiporter. Besides the involvement in acid resistance, GABA production and release were found to occur at very high levels in lactic acid bacteria originally isolated from traditionally fermented foods, supporting the evidence that GABA-enriched foods possess health-promoting properties.
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Affiliation(s)
- Daniela De Biase
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze e Biotecnologie Medico-Chirurgiche, Sapienza Università di Roma, 04100, Latina, Italy.
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39
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Tessema GT, Møretrø T, Snipen L, Heir E, Holck A, Naterstad K, Axelsson L. Microarray-based transcriptome ofListeria monocytogenesadapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid. Can J Microbiol 2012; 58:1112-23. [DOI: 10.1139/w2012-091] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies.
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Affiliation(s)
- Girum Tadesse Tessema
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway
| | - Trond Møretrø
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Lars Snipen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
| | - Even Heir
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Askild Holck
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Kristine Naterstad
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Lars Axelsson
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
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40
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Occhialini A, Jiménez de Bagüés MP, Saadeh B, Bastianelli D, Hanna N, De Biase D, Köhler S. The Glutamic Acid Decarboxylase System of the New Species Brucella microti Contributes to Its Acid Resistance and to Oral Infection of Mice. J Infect Dis 2012; 206:1424-32. [DOI: 10.1093/infdis/jis522] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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41
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Characterization of the intracellular glutamate decarboxylase system: analysis of its function, transcription, and role in the acid resistance of various strains of Listeria monocytogenes. Appl Environ Microbiol 2012; 78:3571-9. [PMID: 22407692 DOI: 10.1128/aem.00227-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The glutamate decarboxylase (GAD) system is important for the acid resistance of Listeria monocytogenes. We previously showed that under acidic conditions, glutamate (Glt)/γ-aminobutyrate (GABA) antiport is impaired in minimal media but not in rich ones, like brain heart infusion. Here we demonstrate that this behavior is more complex and it is subject to strain and medium variation. Despite the impaired Glt/GABA antiport, cells accumulate intracellular GABA (GABA(i)) as a standard response against acid in any medium, and this occurs in all strains tested. Since these systems can occur independently of one another, we refer to them as the extracellular (GAD(e)) and intracellular (GAD(i)) systems. We show here that GAD(i) contributes to acid resistance since in a ΔgadD1D2 mutant, reduced GABA(i) accumulation coincided with a 3.2-log-unit reduction in survival at pH 3.0 compared to that of wild-type strain LO28. Among 20 different strains, the GAD(i) system was found to remove 23.11% ± 18.87% of the protons removed by the overall GAD system. Furthermore, the GAD(i) system is activated at milder pH values (4.5 to 5.0) than the GAD(e) system (pH 4.0 to 4.5), suggesting that GAD(i) is the more responsive of the two and the first line of defense against acid. Through functional genomics, we found a major role for GadD2 in the function of GAD(i), while that of GadD1 was minor. Furthermore, the transcription of the gad genes in three common reference strains (10403S, LO28, and EGD-e) during an acid challenge correlated well with their relative acid sensitivity. No transcriptional upregulation of the gadT2D2 operon, which is the most important component of the GAD system, was observed, while gadD3 transcription was the highest among all gad genes in all strains. In this study, we present a revised model for the function of the GAD system and highlight the important role of GAD(i) in the acid resistance of L. monocytogenes.
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Rantsiou K, Greppi A, Garosi M, Acquadro A, Mataragas M, Cocolin L. Strain dependent expression of stress response and virulence genes of Listeria monocytogenes in meat juices as determined by microarray. Int J Food Microbiol 2011; 152:116-22. [PMID: 21924790 DOI: 10.1016/j.ijfoodmicro.2011.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 08/09/2011] [Accepted: 08/10/2011] [Indexed: 12/28/2022]
Abstract
A subgenomic array, encompassing 54 probes targeting genes responsible for virulence, adhesion and stress response in Listeria monocytogenes, was used in order to study their expression in food systems. RNA extracted from L. monocytogenes inoculated in BHI and in situ (i.e. in minced meat and fermented sausage juices) and incubated at 4°C, was hybridized on the array and the results obtained were compared in order to understand the effect that the food juice has on the expression. Three different strains of L. monocytogenes were tested, in order to determine the effect of the strain provenience. As determined by cluster analysis, each strain behaved in a different way when inoculated in food juices. The goal was to respond to acidic and osmotic stresses encountered in the food, particularly in the fermented sausage juice. No differences in the expression profile between the three strains were observed, when they were inoculated in BHI. On the other hand, in the meat and sausage juices, the iap, gadC and gadE genes, together with different internalin encoding genes, were significantly differentially expressed in the three strains.
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Affiliation(s)
- Kalliopi Rantsiou
- Dipartimento di Valorizzazione e Protezione delle Risorse Agroforestali, Section of Agricultural Microbiology and Food Technology, Facoltà di Agraria, Università di Torino, Italy.
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Senouci-Rezkallah K, Schmitt P, Jobin MP. Amino acids improve acid tolerance and internal pH maintenance in Bacillus cereus ATCC14579 strain. Food Microbiol 2011; 28:364-72. [DOI: 10.1016/j.fm.2010.09.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 09/03/2010] [Accepted: 09/06/2010] [Indexed: 10/19/2022]
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Collins B, Cotter PD, Hill C, Ross RP. The impact of nisin on sensitive and resistant mutants of Listeria monocytogenes in cottage cheese. J Appl Microbiol 2011; 110:1509-14. [PMID: 21435121 DOI: 10.1111/j.1365-2672.2011.05005.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
AIMS Listeria monocytogenes ΔgadD1 and ΔlisK mutants display enhanced and reduced sensitivity, respectively, to the food preservative nisin in laboratory media. However, the behaviour of these strains in a nisin-containing food has not been assessed. Here we use cottage cheese as a model food to address this issue. MATERIALS AND RESULTS Antibiotic-resistant forms of the wild-type and mutant strains were employed to investigate the behaviour of multiple strains in a single food sample, thereby eliminating the problem of intersample variation. Using this approach, it was established that percentage survival of the ΔlisK mutant was greater than the parent strain in the absence of nisin and that this relative difference became even more dramatic in cottage cheese supplemented with nisin. The numbers of the ΔgadD1 mutant decreased more rapidly than the parent in cottage cheese without nisin, but surprisingly this trend was reversed in nisin-supplemented cheese. Upon the addition of 10 mmol l(-1) monosodium glutamate, a substrate for the glutamate decarboxylase (GAD) system, the wild-type LO28 strain regained its relative advantage over ΔgadD1. CONCLUSIONS Care needs to be taken when predicting the behaviour of mutants of L. monocytogenes with altered resistance to nisin in food as experiments in laboratory media are not always a good indicator of how the strains will behave in such food environments. SIGNIFICANCE AND IMPACT OF THE STUDY This study further emphasizes the importance of utilizing food matrices to confirm observations made using laboratory media.
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Affiliation(s)
- B Collins
- Department of Microbiology, University College Cork, Cork, Ireland
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Investigation of the mechanisms by which Listeria monocytogenes grows in porcine gallbladder bile. Infect Immun 2010; 79:369-79. [PMID: 20937762 DOI: 10.1128/iai.00330-10] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The food-borne pathogen Listeria monocytogenes is known to colonize the lumen of the gallbladder in infected mice and to grow rapidly in this environment (J. Hardy et al., Science 303:851-853, 2004). However, relatively little is known about the mechanisms utilized by the pathogen to survive and grow in this location. We utilized gallbladder bile (GB bile) isolated directly from porcine gallbladders as an ex vivo model of gallbladder growth. We demonstrate that GB bile is generally nontoxic for bacteria and can readily support growth of a variety of bacterial species including L. monocytogenes, Lactococcus lactis, Salmonella enterica serovar Typhimurium, and Escherichia coli. Significantly, L. monocytogenes grew at the same rate as the nonpathogenic species Listeria innocua, indicating that the pathogen does not possess specialized mechanisms that enable growth in this environment. However, when we reduced the pH of GB bile to pH 5.5 in order to mimic the release of bile within the small intestine, the toxicity of GB bile increased significantly and specific resistance mechanisms (Sigma B, BSH, and BilE) were essential for survival of the pathogen under these conditions. In order to identify genetic loci that are necessary for growth of L. monocytogenes in the gallbladder, a mariner transposon bank was created and screened for mutants unable to replicate in GB bile. This led to the identification of mutants in six loci, including genes encoding enzymes involved in purine metabolism, amino acid biosynthesis, and biotin uptake. Although GB bile does not represent a significant impediment to bacterial growth, specific metabolic processes are required by L. monocytogenes in order to grow in this environment.
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Glutamate decarboxylase-mediated nisin resistance in Listeria monocytogenes. Appl Environ Microbiol 2010; 76:6541-6. [PMID: 20693450 DOI: 10.1128/aem.00203-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Analysis of a complete set of glutamate decarboxylase (gad) mutants of Listeria monocytogenes strain LO28 (ΔgadD1, ΔgadDT1, ΔgadD2, ΔgadT2, and ΔgadD3 mutants) revealed that the ΔgadD1 mutant is impaired in its ability to tolerate exposure to both sublethal and lethal levels of the lantibiotic nisin. gadD1 is strain variable and is found only in approximately 50% of L. monocytogenes strains. Growth and survival experiments revealed that possession of gadD1 correlates with a higher degree of tolerance to nisin. Significantly, a similar finding using a gadB mutant of L. lactis IL1403 implies that this may be a general phenomenon in Gram-positive bacteria. Our findings thus suggest that the specific inhibition of GAD activity or a reduction in the levels of free glutamate may prevent the growth of otherwise resistant GAD(+) bacteria in foods where low pH and/or nisin is used as a preservative.
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Schuppler M, Loessner MJ. The Opportunistic Pathogen Listeria monocytogenes: Pathogenicity and Interaction with the Mucosal Immune System. Int J Inflam 2010; 2010:704321. [PMID: 21188219 PMCID: PMC3003996 DOI: 10.4061/2010/704321] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 06/01/2010] [Indexed: 12/22/2022] Open
Abstract
Listeria monocytogenes is an opportunistic foodborne pathogen causing listeriosis, an often fatal infection leading to meningitis, sepsis, or infection of the fetus and abortion in susceptible individuals. It was recently found that the bacterium can also cause acute, self-limiting febrile gastroenteritis in healthy individuals. In the intestinal tract, L. monocytogenes penetrates the mucosa directly via enterocytes, or indirectly via invasion of Peyer's patches. Animal models for L. monocytogenes infection have provided many insights into the mechanisms of pathogenesis, and the development of new model systems has allowed the investigation of factors that influence adaptation to the gastrointestinal environment as well as adhesion to and invasion of the intestinal mucosa. The mucosal surfaces of the gastrointestinal tract are permanently exposed to an enormous antigenic load derived from the gastrointestinal microbiota present in the human bowel. The integrity of the important epithelial barrier is maintained by the mucosal immune system and its interaction with the commensal flora via pattern recognition receptors (PRRs). Here, we discuss recent advances in our understanding of the interaction of L. monocytogenes with the host immune system that triggers the antibacterial immune responses on the mucosal surfaces of the human gastrointestinal tract.
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Affiliation(s)
- Markus Schuppler
- Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstraße 7, 8092 Zurich, Switzerland
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Intracellular accumulation of high levels of gamma-aminobutyrate by Listeria monocytogenes 10403S in response to low pH: uncoupling of gamma-aminobutyrate synthesis from efflux in a chemically defined medium. Appl Environ Microbiol 2010; 76:3529-37. [PMID: 20400565 DOI: 10.1128/aem.03063-09] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It is well established that the glutamate decarboxylase (GAD) system is central to the survival of Listeria monocytogenes at low pH, both in acidic foods and within the mammalian stomach. The accepted model proposes that under acidic conditions extracellular glutamate is transported into the cell in exchange for an intracellular gamma-aminobutyrate (GABA(i)). The glutamate is then decarboxylated to GABA(i), a reaction that consumes a proton, thereby helping to prevent acidification of the cytoplasm. In this study, we show that glutamate supplementation had no influence on either growth rate at pH 5.0 or survival at pH 2.5 when L. monocytogenes 10403S was grown in a chemically defined medium (DM). In response to acidification, cells grown in DM failed to efflux GABA, even when glutamate was added to the medium. In contrast, in brain heart infusion (BHI), the same strain produced significant extracellular GABA (GABA(e)) in response to acidification. In addition, high levels of GABA(i) (>80 mM) were found in the cytoplasm in response to low pH in both growth media. Medium-swap and medium-mixing experiments revealed that the GABA efflux apparatus was nonfunctional in DM, even when glutamate was present. It was also found that the GadT2D2 antiporter/decarboxylase system was transcribed poorly in DM-grown cultures while overexpression of gadD1T1 and gadD3 occurred in response to pH 3.5. Interestingly, BHI-grown cells did not respond with upregulation of any of the GAD system genes when challenged at pH 3.5. The accumulation of GABA(i) in cells grown in DM in the absence of extracellular glutamate indicates that intracellular glutamate is the source of the GABA(i). These results demonstrate that GABA production can be uncoupled from GABA efflux, a finding that alters the way we should view the operation of bacterial GAD systems.
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Comparative analysis of acid resistance in Listeria monocytogenes and Salmonella enterica strains before and after exposure to poultry decontaminants. Role of the glutamate decarboxylase (GAD) system. Food Microbiol 2009; 26:905-9. [DOI: 10.1016/j.fm.2009.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 11/19/2022]
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Scollard J, Francis GA, O'Beirne D. Effects of essential oil treatment, gas atmosphere, and storage temperature on Listeria monocytogenes in a model vegetable system. J Food Prot 2009; 72:1209-15. [PMID: 19610331 DOI: 10.4315/0362-028x-72.6.1209] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Natural antimicrobials such as plant essential oils (EOs) may be useful for controlling pathogenic bacteria on fresh-cut vegetables. The antilisterial properties of EOs (thyme, oregano, and rosemary), in combination with different storage atmospheres (air, 5% CO2-2% O2-93% N2, and 20% CO2-1% O2-79% N2) and temperatures (4 and 80C), were examined using a gas flow-through system combined with a vegetable agar model. The antimicrobial effects of the EOs varied depending on the oil, the Listeria strain and species, the method of application, and the storage conditions tested. Using the disk diffusion assay, the antilisterial effectiveness of the oils was in the following order: thyme EO > oregano EO > rosemary EO. Volatiles released from the EOs resulted in very small antilisterial effects, indicating that the oils needed to be in direct contact with cultures in order to be effective. There were strain and species effects, with L. innocua NCTC 11288 exhibiting the strongest resistance to EOs, and L. monocytogenes NCTC 7973 being the most sensitive strain. In addition, the effectiveness of the EOs was influenced by storage atmosphere and temperature. Use of EOs in combination with a gas atmosphere of 20% CO2-1% O2-79% N2 had the greatest antilisterial effect, suggesting that high CO2 atmospheres enhanced the antilisterial properties of EOs. Lowering the storage temperature from 8 to 4OC improved the antilisterial activity of thyme oil. It is concluded that thyme and oregano EOs display strong inhibitory effects against Listeria and that increasing CO2 levels and lowering storage temperatures further enhance these antilisterial effects.
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Affiliation(s)
- Johann Scollard
- Food Science Research Centre, Department of Life Sciences, University of Limerick, Limerick, Ireland
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