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Claudia MV, Javiera AA, Sebastián NS, José FR, Gloria L. Interplay between desiccation and oxidative stress responses in iron-oxidizing acidophilic bacteria. J Biotechnol 2024; 383:64-72. [PMID: 38311245 DOI: 10.1016/j.jbiotec.2024.01.017] [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: 07/17/2023] [Revised: 01/15/2024] [Accepted: 01/30/2024] [Indexed: 02/10/2024]
Abstract
Variations in water availability represent a foremost stress factor affecting the growth and survival of microorganisms. Acidophilic bioleaching bacteria are industrially applied for releasing metals from mineral sulphides, and they are considered extremely tolerant to oxidative conditions prevailing in acidic bioleaching environments. Such processes usually are performed in heaps and thus these microorganisms are also exposed to intermittent desiccations or high osmolarity periods that reduce the water availability. However, the tolerance to water stress and the molecular basis of adaptation to it are still largely unknown. The aim of this work was to determine the cellular response to desiccation stress and establish its relationship to oxidative stress response in the acidophilic iron-oxidizing bacteria Acidithiobacillus ferrooxidans ATCC 23270 and Leptospirillum ferriphilum DSM 14647. Results showed that the exposure of cell cultures to desiccation (0-120 min) led to a significant reduction in cell growth, and to an increase in content in reactive oxygen species in both bacteria. However, Leptospirillum ferriphilum turned out to be more tolerant than Acidithiobacillus ferrooxidans. In addition, the pre-treatment of the cell cultures with compatible solutes (trehalose and ectoine), and antioxidants (glutathione and cobalamin) restored all stress parameters to levels exhibited by the control cultures. To evaluate the role of the osmotic and redox homeostasis mechanisms in coping with desiccation stress, the relative expression of a set of selected genes was approached by RT-qPCR experiments in cells exposed to desiccation for 30 min. Results showed a generalized upregulation of genes that code for mechanosensitive channels, and enzymes related to the biosynthesis of compatible solutes and oxidative stress response in both bacteria. These data suggest that acidophiles show variable tolerance to desiccation and allow to establish that water stress can trigger oxidative stress, and thus anti-oxidative protection capability can be a relevant mechanism when cells are challenged by desiccation or other anhydrobiosis states.
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Affiliation(s)
- Muñoz-Villagrán Claudia
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Av. Libertador Bernardo O'Higgins, Santiago 3363, Chile
| | - Acevedo-Arbunic Javiera
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Av. Libertador Bernardo O'Higgins, Santiago 3363, Chile
| | - Navarro-Salazar Sebastián
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Av. Libertador Bernardo O'Higgins, Santiago 3363, Chile
| | - Fuentes-Rubio José
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Av. Libertador Bernardo O'Higgins, Santiago 3363, Chile
| | - Levicán Gloria
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Av. Libertador Bernardo O'Higgins, Santiago 3363, Chile.
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Zaccaria T, de Jonge MI, Domínguez-Andrés J, Netea MG, Beblo-Vranesevic K, Rettberg P. Survival of Environment-Derived Opportunistic Bacterial Pathogens to Martian Conditions: Is There a Concern for Human Missions to Mars? ASTROBIOLOGY 2024; 24:100-113. [PMID: 38227836 DOI: 10.1089/ast.2023.0057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The health of astronauts during space travel to new celestial bodies in the Solar System is a critical factor in the planning of a mission. Despite cleaning and decontamination protocols, microorganisms from the Earth have been and will be identified on spacecraft. This raises concerns for human safety and planetary protection, especially if these microorganisms can evolve and adapt to the new environment. In this study, we examined the tolerance of clinically relevant nonfastidious bacterial species that originate from environmental sources (Burkholderia cepacia, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens) to simulated martian conditions. Our research showed changes in growth and survival of these species in the presence of perchlorates, under desiccating conditions, exposure to ultraviolet radiation, and exposure to martian atmospheric composition and pressure. In addition, our results demonstrate that growth was enhanced by the addition of a martian regolith simulant to the growth media. Additional future research is warranted to examine potential changes in the infectivity, pathogenicity, and virulence of these species with exposure to martian conditions.
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Affiliation(s)
- Tommaso Zaccaria
- Research Group Astrobiology, Radiation Biology Department, Institute of Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Cologne, Germany
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Marien I de Jonge
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Laboratory of Medical Immunology, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jorge Domínguez-Andrés
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Mihai G Netea
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, Netherlands
- Department for Immunology and Metabolism, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Kristina Beblo-Vranesevic
- Research Group Astrobiology, Radiation Biology Department, Institute of Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Cologne, Germany
| | - Petra Rettberg
- Research Group Astrobiology, Radiation Biology Department, Institute of Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Cologne, Germany
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Detert K, Währer J, Nieselt K, Schmidt H. Broad time-dependent transcriptional activity of metabolic genes of E. coli O104:H4 strain C227/11Φcu in a soil microenvironment at low temperature. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:582-596. [PMID: 37644642 PMCID: PMC10667640 DOI: 10.1111/1758-2229.13198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023]
Abstract
In the current study, metabolic genes and networks that influence the persistence of pathogenic Escherichia coli O104:H4 strain C227/11Φcu in agricultural soil microenvironments at low temperature were investigated. The strain was incubated in alluvial loam (AL) and total RNA was prepared from samples at time point 0, and after 1 and 4 weeks. Differential transcriptomic analysis was performed by RNA sequencing analysis and values obtained at weeks 1 and 4 were compared to those of time point 0. We found differential expression of more than 1500 genes for either time point comparison. The two lists of differentially expressed genes were then subjected to gene set enrichment of Gene Ontology terms. In total, 17 GO gene sets and 3 Pfam domains were found to be enriched after 1 week. After 4 weeks, 17 GO gene sets and 7 Pfam domains were statistically enriched. Especially stress response genes and genes of the primary metabolism were particularly affected at both time points. Genes and gene sets for uptake of carbohydrates, amino acids were strongly upregulated, indicating adjustment to a low nutrient environment. The results of this transcriptome analysis show that persistence of C227/11Φcu in soils is associated with a complex interplay of metabolic networks.
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Affiliation(s)
- Katharina Detert
- Department of Food Microbiology and Hygiene, Institute of Food Science and BiotechnologyUniversity of HohenheimStuttgartGermany
| | - Jonathan Währer
- Institute for Bioinformatics and Medical InformaticsUniversity of TübingenTübingenGermany
| | - Kay Nieselt
- Institute for Bioinformatics and Medical InformaticsUniversity of TübingenTübingenGermany
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and BiotechnologyUniversity of HohenheimStuttgartGermany
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Loiko N, Tereshkina K, Kovalenko V, Moiseenko A, Tereshkin E, Sokolova OS, Krupyanskii Y. DNA-Binding Protein Dps Protects Escherichia coli Cells against Multiple Stresses during Desiccation. BIOLOGY 2023; 12:853. [PMID: 37372138 DOI: 10.3390/biology12060853] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
Gradual dehydration is one of the frequent lethal yet poorly understood stresses that bacterial cells constantly face in the environment when their micro ecotopes dry out, as well as in industrial processes. Bacteria successfully survive extreme desiccation through complex rearrangements at the structural, physiological, and molecular levels, in which proteins are involved. The DNA-binding protein Dps has previously been shown to protect bacterial cells from many adverse effects. In our work, using engineered genetic models of E. coli to produce bacterial cells with overproduction of Dps protein, the protective function of Dps protein under multiple desiccation stresses was demonstrated for the first time. It was shown that the titer of viable cells after rehydration in the experimental variants with Dps protein overexpression was 1.5-8.5 times higher. Scanning electron microscopy was used to show a change in cell morphology upon rehydration. It was also proved that immobilization in the extracellular matrix, which is greater when the Dps protein is overexpressed, helps the cells survive. Transmission electron microscopy revealed disruption of the crystal structure of DNA-Dps crystals in E. coli cells that underwent desiccation stress and subsequent watering. Coarse-grained molecular dynamics simulations showed the protective function of Dps in DNA-Dps co-crystals during desiccation. The data obtained are important for improving biotechnological processes in which bacterial cells undergo desiccation.
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Affiliation(s)
- Nataliya Loiko
- Winogradsky Institute of Microbiology, Fundamentals of Biotechnology Federal Research Center, Russian Academy of Sciences, 117312 Moscow, Russia
| | - Ksenia Tereshkina
- Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Vladislav Kovalenko
- Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Andrey Moiseenko
- Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Eduard Tereshkin
- Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Olga S Sokolova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Yurii Krupyanskii
- Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
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Diaz CI, Molina S, Smith MW, Rohla C, Ma LM. Prevalence of Shiga Toxin-Producing Escherichia coli and Salmonella in Native Pecan Orchards as Influenced by Waiting Periods between Grazing and Harvest. J Food Prot 2022; 85:36-43. [PMID: 34499730 DOI: 10.4315/jfp-21-163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 09/07/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT Animals (grazing, working, or intrusion) in produce production areas may present a potential contamination source of foodborne pathogens on produce. Cattle grazing on native pecan production orchards, a common practice in the southern United States, provides an opportunity to study the impact of grazing practice and waiting periods on contamination rates of foodborne pathogens of tree nuts. Therefore, the objective of this study was to determine the prevalence of Salmonella and Shiga toxin-producing Escherichia coli (STEC) in native pecan production orchards as influenced by waiting periods between grazing cattle and pecan harvest. Soil (10 g), cattle feces (10 g), and in-shell pecans (25 g) were sampled from five cattle-grazed orchards in areas with cattle removed 2 or 4 months before harvest and not removed. Five nongrazing orchards were sampled at harvest for comparison. Detection and isolation of the pathogens were performed by enrichment, selective isolation, and multiplex PCR. Statistical analyses were performed using contingency tables with Pearson's chi-square test. The prevalence of STEC (36%) and Salmonella (29%) in cattle-grazed orchards was significantly higher than in nongrazed orchards (13 and 7%, respectively). STEC prevalence in cattle-grazed orchards was higher (38%) in areas with cattle at harvest than in fenced areas where cattle were removed 2 (29%) and 4 (27%) months before harvest. Salmonella prevalence was similar in areas without fencing (31%) and areas with cattle removed at 2 (22%) and 4 (30%) months before harvest. However, there were no significant differences (P > 0.05) in contamination rates between waiting periods for either pathogen, suggesting a limited impact of waiting periods on reducing the risk of contamination. HIGHLIGHTS
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Affiliation(s)
- Claudia I Diaz
- Institute for Biosecurity and Microbial Forensics, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078
| | - Santiago Molina
- Institute for Biosecurity and Microbial Forensics, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078
| | - Michael W Smith
- Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, Oklahoma 74078
| | - Charles Rohla
- Noble Research Institute, Ardmore, Oklahoma 73401, USA
| | - Li Maria Ma
- Institute for Biosecurity and Microbial Forensics, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078
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Detert K, Schmidt H. Survival of Enterohemorrhagic Escherichia coli O104:H4 Strain C227/11Φcu in Agricultural Soils Depends on rpoS and Environmental Factors. Pathogens 2021; 10:pathogens10111443. [PMID: 34832598 PMCID: PMC8620961 DOI: 10.3390/pathogens10111443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 11/19/2022] Open
Abstract
The consumption of contaminated fresh produce caused outbreaks of enterohemorrhagic (EHEC) Escherichia coli. Agricultural soil might be a reservoir for EHEC strains and represent a contamination source for edible plants. Furthermore, the application of manure as fertilizer is an important contamination route. Thus, the German fertilizer ordinance prohibits the use of manure 12 weeks before crop harvest to avoid pathogen transmission into the food chain. In this study, the survival of E. coli O104:H4 strain C227/11Φcu in soil microenvironments with either diluvial sand or alluvial loam at two temperatures was investigated for more than 12 weeks. It was analyzed whether the addition of cattle manure extends EHEC survival in these microenvironments. The experiments were additionally performed with isogenic ΔrpoS and ΔfliC deletion mutants of C227/11Φcu. The survival of C227/11Φcu was highest at 4 °C, whereas the soil type had a minor influence. The addition of cattle manure increased the survival at 22 °C. Deletion of rpoS significantly decreased the survival period under all cultivation conditions, whereas fliC deletion did not have any influence. The results of our study demonstrate that EHEC C227/11Φcu is able to survive for more than 12 weeks in soil microenvironments and that RpoS is an important determinant for survival.
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7
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Survival of acid-adapted and non-adapted Shiga toxin-producing Escherichia coli using an in vitro model. Food Control 2019. [DOI: 10.1016/j.foodcont.2019.04.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Chen AI, Goulian M. A network of regulators promotes dehydration tolerance in Escherichia coli. Environ Microbiol 2018; 20:1283-1295. [PMID: 29457688 DOI: 10.1111/1462-2920.14074] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/13/2018] [Accepted: 02/12/2018] [Indexed: 01/09/2023]
Abstract
The ability to survive conditions of low water activity is critical for the survival of many bacteria in the environment and facilitates disease transmission through food and contaminated surfaces. However, the molecular mechanisms that enable bacteria to withstand this condition remain poorly understood. Here we describe a network of regulators in Escherichia coli that are important for this bacterium to survive dehydration. We found that the transcriptional regulator DksA and the general stress response regulator RpoS play a critical role. From a plasmid genomic library screen, we identified two additional regulators, Crl and ArcZ, that promote dehydration tolerance through modulation of RpoS. We also found that LexA, RecA and ArcA contribute to survival. Our results identify key regulators that enable E. coli to tolerate dehydration and suggest a hierarchical network is involved in protection against cellular damage associated with this stress.
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Affiliation(s)
- Annie I Chen
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark Goulian
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.,Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA, USA
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Somorin Y, Bouchard G, Gallagher J, Abram F, Brennan F, O’Byrne C. Roles for RpoS in survival of Escherichia coli during protozoan predation and in reduced moisture conditions highlight its importance in soil environments. FEMS Microbiol Lett 2017; 364:4159366. [DOI: 10.1093/femsle/fnx198] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/13/2017] [Indexed: 11/13/2022] Open
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Thermal Resistance and Gene Expression of both Desiccation-Adapted and Rehydrated Salmonella enterica Serovar Typhimurium Cells in Aged Broiler Litter. Appl Environ Microbiol 2017; 83:AEM.00367-17. [PMID: 28389541 DOI: 10.1128/aem.00367-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/04/2017] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to investigate the thermal resistance and gene expression of both desiccation-adapted and rehydrated Salmonella enterica serovar Typhimurium cells in aged broiler litter. S Typhimurium was desiccation adapted in aged broiler litter with a 20% moisture content (water activity [aw], 0.81) for 1, 2, 3, 12, or 24 h at room temperature and then rehydrated for 3 h. As analyzed by quantitative real-time reverse transcriptase PCR (qRT-PCR), the rpoS, proV, dnaK, and grpE genes were upregulated (P < 0.05) under desiccation stress and could be induced after 1 h but in less than 2 h. Following rehydration, fold changes in the levels of these four genes became significantly lower (P < 0.05). The desiccation-adapted ΔrpoS mutant was less heat resistant at 75°C than was the desiccation-adapted wild type (P < 0.05), whereas there were no differences in heat resistance between desiccation-adapted mutants in two nonregulated genes (otsA and PagfD) and the desiccation-adapted wild type (P > 0.05). Survival characteristics of the desiccation-adapted ΔPagfD (rdar [red, dry, and rough] morphotype) and ΔagfD (saw [smooth and white] morphotype) mutants were similar (P > 0.05). Trehalose synthesis in the desiccation-adapted wild type was not induced compared to a nonadapted control (P > 0.05). Our results demonstrated the importance of the rpoS, proV, dnaK, and grpE genes in the desiccation survival of S Typhimurium. By using an ΔrpoS mutant, we found that the rpoS gene was involved in the cross-protection of desiccation-adapted S Typhimurium against high temperatures, while trehalose synthesis or rdar morphology did not play a significant role in this phenomenon. In summary, S Typhimurium could respond rapidly to low-aw conditions in aged broiler litter while developing cross-protection against high temperatures, but this process could be reversed upon rehydration.IMPORTANCE Physical heat treatment is effective in eliminating human pathogens from poultry litter used as biological soil amendments. However, prior to physical heat treatment, some populations of microorganisms may be adapted to the stressful conditions in poultry litter during composting or stockpiling, which may cross-protect them against subsequent high temperatures. Our previous study demonstrated that desiccation-adapted S. enterica cells in aged broiler litter exhibited enhanced thermal resistance. However, there is limited research on the underlying mechanisms of the extended survival of pathogens under desiccation conditions in animal wastes and cross-tolerance to subsequent heat treatment. Moreover, no information is available about the thermal resistance of desiccation-adapted microorganisms in response to rehydration. Therefore, in the present study, we investigated the gene expression and thermal resistance of both desiccation-adapted and rehydrated S Typhimurium in aged broiler litter. This work will guide future research efforts to control human pathogens in animal wastes used as biological soil amendments.
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The General Stress Response Is Conserved in Long-Term Soil-Persistent Strains of Escherichia coli. Appl Environ Microbiol 2016; 82:4628-4640. [PMID: 27235429 DOI: 10.1128/aem.01175-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 05/12/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Although Escherichia coli is generally considered to be predominantly a commensal of the gastrointestinal tract, a number of recent studies suggest that it is also capable of long-term survival and growth in environments outside the host. As the extraintestinal physical and chemical conditions are often different from those within the host, it is possible that distinct genetic adaptations may be required to enable this transition. Several studies have shown a trade-off between growth and stress resistance in nutrient-poor environments, with lesions in the rpoS locus, which encodes the stress sigma factor RpoS (σ(S)). In this study, we investigated a unique collection of long-term soil-persistent E. coli isolates to determine whether the RpoS-controlled general stress response is altered during adaptation to a nutrient-poor extraintestinal environment. The sequence of the rpoS locus was found to be highly conserved in these isolates, and no nonsense or frameshift mutations were detected. Known RpoS-dependent phenotypes, including glycogen synthesis and γ-aminobutyrate production, were found to be conserved in all strains. All strains expressed the full-length RpoS protein, which was fully functional using the RpoS-dependent promoter reporter fusion PgadX::gfp RpoS was shown to be essential for long-term soil survival of E. coli, since mutants lacking rpoS lost viability rapidly in soil survival assays. Thus, despite some phenotypic heterogeneity, the soil-persistent strains all retained a fully functional RpoS-regulated general stress response, which we interpret to indicate that the stresses encountered in soil provide a strong selective pressure for maintaining stress resistance, despite limited nutrient availability. IMPORTANCE Escherichia coli has been, and continues to be, used as an important indicator species reflecting potential fecal contamination events in the environment. However, recent studies have questioned the validity of this, since E. coli has been found to be capable of long-term colonization of soils. This study investigated whether long-term soil-persistent E. coli strains have evolved altered stress resistance characteristics. In particular, the study investigated whether the main regulator of genes involved in stress protection, the sigma factor RpoS, has been altered in the soil-persistent strains. The results show that RpoS stress protection is fully conserved in soil-persistent strains of E. coli They also show that loss of the rpoS gene dramatically reduces the ability of this organism to survive in a soil environment. Overall, the results indicate that soil represents a stressful environment for E. coli, and their survival in it requires that they deploy a full stress protection response.
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Métris A, George SM, Ropers D. Piecewise linear approximations to model the dynamics of adaptation to osmotic stress by food-borne pathogens. Int J Food Microbiol 2016; 240:63-74. [PMID: 27377009 DOI: 10.1016/j.ijfoodmicro.2016.06.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 06/09/2016] [Accepted: 06/19/2016] [Indexed: 01/08/2023]
Abstract
Addition of salt to food is one of the most ancient and most common methods of food preservation. However, little is known of how bacterial cells adapt to such conditions. We propose to use piecewise linear approximations to model the regulatory adaptation of Escherichiacoli to osmotic stress. We apply the method to eight selected genes representing the functions known to be at play during osmotic adaptation. The network is centred on the general stress response factor, sigma S, and also includes a module representing the catabolic repressor CRP-cAMP. Glutamate, potassium and supercoiling are combined to represent the intracellular regulatory signal during osmotic stress induced by salt. The output is a module where growth is represented by the concentration of stable RNAs and the transcription of the osmotic gene osmY. The time course of gene expression of transport of osmoprotectant represented by the symporter proP and of the osmY is successfully reproduced by the network. The behaviour of the rpoS mutant predicted by the model is in agreement with experimental data. We discuss the application of the model to food-borne pathogens such as Salmonella; although the genes considered have orthologs, it seems that supercoiling is not regulated in the same way. The model is limited to a few selected genes, but the regulatory interactions are numerous and span different time scales. In addition, they seem to be condition specific: the links that are important during the transition from exponential to stationary phase are not all needed during osmotic stress. This model is one of the first steps towards modelling adaptation to stress in food safety and has scope to be extended to other genes and pathways, other stresses relevant to the food industry, and food-borne pathogens. The method offers a good compromise between systems of ordinary differential equations, which would be unmanageable because of the size of the system and for which insufficient data are available, and the more abstract Boolean methods.
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Affiliation(s)
- Aline Métris
- Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Susie M George
- Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Delphine Ropers
- Inria Grenoble - Rhône-Alpes Research Center, Saint Ismier, France.
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13
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Tarusawa T, Ito S, Goto S, Ushida C, Muto A, Himeno H. (p)ppGpp-dependent and -independent pathways for salt tolerance inEscherichia coli. J Biochem 2016; 160:19-26. [DOI: 10.1093/jb/mvw008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 12/27/2015] [Indexed: 11/13/2022] Open
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14
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The response of foodborne pathogens to osmotic and desiccation stresses in the food chain. Int J Food Microbiol 2016; 221:37-53. [PMID: 26803272 DOI: 10.1016/j.ijfoodmicro.2015.12.014] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/22/2015] [Accepted: 12/30/2015] [Indexed: 12/24/2022]
Abstract
In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products.
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15
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Yoo BK, Liu Y, Juneja V, Huang L, Hwang CA. Growth characteristics of Shiga toxin-producing Escherichia coli (STEC) stressed by chlorine, sodium chloride, acid, and starvation on lettuce and cantaloupe. Food Control 2015. [DOI: 10.1016/j.foodcont.2015.02.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Stevenson A, Burkhardt J, Cockell CS, Cray JA, Dijksterhuis J, Fox-Powell M, Kee TP, Kminek G, McGenity TJ, Timmis KN, Timson DJ, Voytek MA, Westall F, Yakimov MM, Hallsworth JE. Multiplication of microbes below 0.690 water activity: implications for terrestrial and extraterrestrial life. Environ Microbiol 2014; 17:257-77. [DOI: 10.1111/1462-2920.12598] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/08/2014] [Accepted: 08/14/2014] [Indexed: 01/25/2023]
Affiliation(s)
- Andrew Stevenson
- Institute for Global Food Security; School of Biological Sciences; MBC; Queen's University Belfast; Belfast BT9 7BL Northern Ireland
| | - Jürgen Burkhardt
- Plant Nutrition Group; Institute of Crop Science and Resource Conservation; University of Bonn; Karlrobert-Kreiten-Str. 13 D-53115 Bonn Germany
| | - Charles S. Cockell
- UK Centre for Astrobiology; School of Physics and Astronomy; University of Edinburgh; Edinburgh EH9 3JZ UK
| | - Jonathan A. Cray
- Institute for Global Food Security; School of Biological Sciences; MBC; Queen's University Belfast; Belfast BT9 7BL Northern Ireland
| | - Jan Dijksterhuis
- CBS Fungal Biodiversity Centre; Uppsalalaan 8 CT 3584 Utrecht The Netherlands
| | - Mark Fox-Powell
- UK Centre for Astrobiology; School of Physics and Astronomy; University of Edinburgh; Edinburgh EH9 3JZ UK
| | - Terence P. Kee
- School of Chemistry; University of Leeds; Leeds LS2 9JT West Yorkshire UK
| | | | - Terry J. McGenity
- School of Biological Sciences; University of Essex; Colchester CO4 3SQ Essex UK
| | - Kenneth N. Timmis
- Institute of Microbiology; Technical University Braunschweig; Spielmannstrasse 7 D-38106 Braunschweig Germany
| | - David J. Timson
- Institute for Global Food Security; School of Biological Sciences; MBC; Queen's University Belfast; Belfast BT9 7BL Northern Ireland
| | | | - Frances Westall
- Centre de Biophysique Moléculaire; CNRS; Rue Charles Sadron; Centre de Recherches sur les Matériaux à Haute Température; 1D, avenue de la recherché scientifique 45071 Orléans Cedex 2 France
| | | | - John E. Hallsworth
- Institute for Global Food Security; School of Biological Sciences; MBC; Queen's University Belfast; Belfast BT9 7BL Northern Ireland
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Mondani L, Roupioz Y, Delannoy S, Fach P, Livache T. Simultaneous enrichment and optical detection of low levels of stressed Escherichia coli
O157:H7 in food matrices. J Appl Microbiol 2014; 117:537-46. [DOI: 10.1111/jam.12522] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 04/08/2014] [Accepted: 04/08/2014] [Indexed: 11/29/2022]
Affiliation(s)
- L. Mondani
- SPrAM; UMR 5819 CEA/CNRS/UJF-Grenoble 1; Institute for Nanosciences & Cryogeny; Grenoble France
| | - Y. Roupioz
- SPrAM; UMR 5819 CEA/CNRS/UJF-Grenoble 1; Institute for Nanosciences & Cryogeny; Grenoble France
| | - S. Delannoy
- French Agency for Food, Environmental and Occupational Health and Safety (ANSES); Food Safety Laboratory; Maisons-Alfort France
| | - P. Fach
- French Agency for Food, Environmental and Occupational Health and Safety (ANSES); Food Safety Laboratory; Maisons-Alfort France
| | - T. Livache
- SPrAM; UMR 5819 CEA/CNRS/UJF-Grenoble 1; Institute for Nanosciences & Cryogeny; Grenoble France
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Transmission of Escherichia coli O157:H7 in cattle is influenced by the level of environmental contamination. Epidemiol Infect 2014; 143:274-87. [PMID: 24731271 PMCID: PMC4301210 DOI: 10.1017/s0950268814000867] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A pen infection-transmission experiment was conducted to elucidate the role of pathogen strain and environmental contamination in transmission of Escherichia coli O157:H7 (ECO157) in cattle. Five steers were inoculated with a three-strain mixture of ECO157 and joined with five susceptible steers in each of two experimental replicates. Faecal and environmental samples were monitored for ECO157 presence over 30 days. One ECO157 strain did not spread. Transmission rates for the other two strains were estimated using a generalized linear model developed based on a modified ‘Susceptible–Infectious–Susceptible’ mathematical model. Transmission rates estimated for the two strains (0·11 and 0·14) were similar. However, the rates significantly (P = 0·0006) increased 1·5 times for every 1-unit increase in the level of environmental contamination measured as log10 c.f.u. Depending on the level of environmental contamination, the estimated basic reproduction numbers varied from <1 to 8. The findings indicate the importance of on-farm measures to reduce environmental contamination for ECO157 control in cattle that should be validated under field conditions.
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The stress response factor RpoS is required for the natural transformation of Escherichia coli. CHINESE SCIENCE BULLETIN-CHINESE 2014. [DOI: 10.1007/s11434-013-0014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Ryu EH, Chang HC. In vitro study of potentially probiotic lactic acid bacteria strains isolated from kimchi. ANN MICROBIOL 2013. [DOI: 10.1007/s13213-013-0599-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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