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Koutsoumanis K, Allende A, Bolton D, Bover‐Cid S, Chemaly M, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Nonno R, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Fox E, Gosling R(B, Gil BM, Møretrø T, Stessl B, da Silva Felício MT, Messens W, Simon AC, Alvarez‐Ordóñez A. Persistence of microbiological hazards in food and feed production and processing environments. EFSA J 2024; 22:e8521. [PMID: 38250499 PMCID: PMC10797485 DOI: 10.2903/j.efsa.2024.8521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024] Open
Abstract
Listeria monocytogenes (in the meat, fish and seafood, dairy and fruit and vegetable sectors), Salmonella enterica (in the feed, meat, egg and low moisture food sectors) and Cronobacter sakazakii (in the low moisture food sector) were identified as the bacterial food safety hazards most relevant to public health that are associated with persistence in the food and feed processing environment (FFPE). There is a wide range of subtypes of these hazards involved in persistence in the FFPE. While some specific subtypes are more commonly reported as persistent, it is currently not possible to identify universal markers (i.e. genetic determinants) for this trait. Common risk factors for persistence in the FFPE are inadequate zoning and hygiene barriers; lack of hygienic design of equipment and machines; and inadequate cleaning and disinfection. A well-designed environmental sampling and testing programme is the most effective strategy to identify contamination sources and detect potentially persistent hazards. The establishment of hygienic barriers and measures within the food safety management system, during implementation of hazard analysis and critical control points, is key to prevent and/or control bacterial persistence in the FFPE. Once persistence is suspected in a plant, a 'seek-and-destroy' approach is frequently recommended, including intensified monitoring, the introduction of control measures and the continuation of the intensified monitoring. Successful actions triggered by persistence of L. monocytogenes are described, as well as interventions with direct bactericidal activity. These interventions could be efficient if properly validated, correctly applied and verified under industrial conditions. Perspectives are provided for performing a risk assessment for relevant combinations of hazard and food sector to assess the relative public health risk that can be associated with persistence, based on bottom-up and top-down approaches. Knowledge gaps related to bacterial food safety hazards associated with persistence in the FFPE and priorities for future research are provided.
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Zerouki C, Chakraborty K, Kuittinen S, Pappinen A, Turunen O. Whole-genome sequence and mass spectrometry study of the snow blight fungus Phacidium infestans (Karsten) DSM 5139 growing at freezing temperatures. Mol Genet Genomics 2023; 298:1449-1466. [PMID: 37815644 PMCID: PMC10657286 DOI: 10.1007/s00438-023-02073-7] [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: 06/12/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Phacidium infestans (synonym Gremmenia infestans) is a significant pathogen that impacts Pinus species across the northern regions of Europe and Asia. This study introduces the genome sequence of P. infestans Karsten DSM 5139 (Phain), obtained through Pacbio technology. The assembly resulted in 44 contigs, with a total genome size of 36,805,277 bp and a Guanine-Cytosine content of 46.4%. Genome-mining revealed numerous putative biosynthetic gene clusters that code for virulence factors and fungal toxins. The presence of the enzyme pisatin demethylase was indicative of the potential of Phain to detoxify its environment from the terpenoid phytoalexins produced by its host as a defense mechanism. Proteomic analysis revealed the potential survival strategies of Phain under the snow, which included the production of antifreeze proteins, trehalose synthesis enzymes, desaturases, proteins related to elongation of very long-chain fatty acids, and stress protein responses. Study of protein GH11 endoxylanase expressed in Escherichia coli showed an acidic optimum pH (pH 5.0) and a low optimum temperature (45 °C), which is reflective of the living conditions of the fungus. Mass spectrometry analysis of the methanol extract of Phain, incubated at - 3 °C and 22 °C, revealed differences in the produced metabolites. Both genomic and mass spectrometry analyses showed the ability of Phain to adapt its metabolic processes and secretome to freezing temperatures through the production of osmoprotectant and cryoprotectant metabolites. This comprehensive exploration of Phain's genome sequence, proteome, and secretome not only advances our understanding of its unique adaptive mechanisms but also expands the possibilities of biotechnological applications.
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Affiliation(s)
- C Zerouki
- School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, 80101, Joensuu, Finland.
| | - K Chakraborty
- School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, 80101, Joensuu, Finland
| | - S Kuittinen
- School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, 80101, Joensuu, Finland
| | - A Pappinen
- School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, 80101, Joensuu, Finland
| | - O Turunen
- School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, 80101, Joensuu, Finland
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Myintzaw P, Pennone V, McAuliffe O, Begley M, Callanan M. Association of Virulence, Biofilm, and Antimicrobial Resistance Genes with Specific Clonal Complex Types of Listeria monocytogenes. Microorganisms 2023; 11:1603. [PMID: 37375105 DOI: 10.3390/microorganisms11061603] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Precise classification of foodborne pathogen Listeria monocytogenes is a necessity in efficient foodborne disease surveillance, outbreak detection, and source tracking throughout the food chain. In this study, a total of 150 L. monocytogenes isolates from various food products, food processing environments, and clinical sources were investigated for variations in virulence, biofilm formation, and the presence of antimicrobial resistance genes based on their Whole-Genome Sequences. Clonal complex (CC) determination based on Multi-Locus Sequence Typing (MLST) revealed twenty-eight CC-types including eight isolates representing novel CC-types. The eight isolates comprising the novel CC-types share the majority of the known (cold and acid) stress tolerance genes and are all genetic lineage II, serogroup 1/2a-3a. Pan-genome-wide association analysis by Scoary using Fisher's exact test identified eleven genes specifically associated with clinical isolates. Screening for the presence of antimicrobial and virulence genes using the ABRicate tool uncovered variations in the presence of Listeria Pathogenicity Islands (LIPIs) and other known virulence genes. Specifically, the distributions of actA, ecbA, inlF, inlJ, lapB, LIPI-3, and vip genes across isolates were found to be significantly CC-dependent while the presence of ami, inlF, inlJ, and LIPI-3 was associated with clinical isolates specifically. In addition, Roary-derived phylogenetic grouping based on Antimicrobial-Resistant Genes (AMRs) revealed that the thiol transferase (FosX) gene was present in all lineage I isolates, and the presence of the lincomycin resistance ABC-F-type ribosomal protection protein (lmo0919_fam) was also genetic-lineage-dependent. More importantly, the genes found to be specific to CC-type were consistent when a validation analysis was performed with fully assembled, high-quality complete L. monocytogenes genome sequences (n = 247) extracted from the National Centre for Biotechnology Information (NCBI) microbial genomes database. This work highlights the usefulness of MLST-based CC typing using the Whole-Genome Sequence as a tool in classifying isolates.
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Affiliation(s)
- Peter Myintzaw
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland
| | - Vincenzo Pennone
- Teagasc Food Research Centre, Moorepark, Fermoy, Co., P61 C996 Cork, Ireland
| | - Olivia McAuliffe
- Teagasc Food Research Centre, Moorepark, Fermoy, Co., P61 C996 Cork, Ireland
| | - Máire Begley
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland
| | - Michael Callanan
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland
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Variability in Cold Tolerance of Food and Clinical Listeria monocytogenes Isolates. Microorganisms 2022; 11:microorganisms11010065. [PMID: 36677357 PMCID: PMC9862054 DOI: 10.3390/microorganisms11010065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022] Open
Abstract
The aim of this study was to investigate the level of strain variability amongst food and clinical Listeria monocytogenes isolates growing at low temperatures (4 and 7 °C) in both laboratory media and real food matrices. Isolates (n = 150) grown in laboratory media demonstrated a large variation in growth profiles measured using optical density. Overall, it was noted that clinical isolates exhibited a significantly higher growth rate (p ≤ 0.05) at 7 °C than the other isolates. Analysis of variance (ANOVA) tests of isolates grouped using Multi Locus Sequence Typing (MLST) revealed that clonal complex 18 (CC18) isolates were significantly (p ≤ 0.05) faster growing at 4 °C than other CC-type isolates while CC101, CC18, CC8, CC37 and CC14 were faster growing than other CC types at 7 °C. Euclidean distance and Ward method-based hierarchical clustering of mean growth rates classified 33.33% of isolates as faster growing. Fast and slow growing representative isolates were selected from the cluster analysis and growth rates were determined using plate count data in laboratory media and model food matrices. In agreement with the optical density experiments, CC18 isolates were faster and CC121 isolates were slower than other CC types in laboratory media, UHT milk and fish pie. The same trend was observed in chocolate milk but the differences were not statistically significant. Moreover, pan-genome analysis (Scoary) of isolate genome sequences only identified six genes of unknown function associated with increased cold tolerance while failing to identify any known cold tolerance genes. Overall, an association that was consistent in laboratory media and real food matrices was demonstrated between isolate CC type and increased cold tolerance.
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Muchaamba F, von Ah U, Stephan R, Stevens MJA, Tasara T. Deciphering the global roles of Cold shock proteins in Listeria monocytogenes nutrient metabolism and stress tolerance. Front Microbiol 2022; 13:1057754. [PMID: 36605504 PMCID: PMC9808409 DOI: 10.3389/fmicb.2022.1057754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022] Open
Abstract
Listeria monocytogenes (Lm) accounts for serious public health and food safety problems owing to its stress resilience and pathogenicity. Based on their regulatory involvement in global gene expression events, cold-shock domain family proteins (Csps) are crucial in expression of various stress fitness and virulence phenotypes in bacteria. Lm possesses three Csps (CspA, CspB, and CspD) whose regulatory roles in the context of the genetic diversity of this bacterium are not yet fully understood. We examined the impacts of Csps deficiency on Lm nutrient metabolism and stress tolerance using a set of csp deletion mutants generated in different genetic backgrounds. Phenotype microarrays (PM) analysis showed that the absence of Csps in ∆cspABD reduces carbon (C-) source utilization capacity and increases Lm sensitivity to osmotic, pH, various chemical, and antimicrobial stress conditions. Single and double csp deletion mutants in different Lm genetic backgrounds were used to further dissect the roles of individual Csps in these phenotypes. Selected PM-based observations were further corroborated through targeted phenotypic assays, confirming that Csps are crucial in Lm for optimal utilization of various C-sources including rhamnose and glucose as well as tolerance against NaCl, β-phenyethylamine (PEA), and food relevant detergent stress conditions. Strain and genetic lineage background-based differences, division of labour, epistasis, and functional redundancies among the Csps were uncovered with respect to their roles in various processes including C-source utilization, cold, and PEA stress resistance. Finally, targeted transcriptome analysis was performed, revealing the activation of csp gene expression under defined stress conditions and the impact of Csps on expression regulation of selected rhamnose utilization genes. Overall, our study shows that Csps play important roles in nutrient utilization and stress responses in Lm strains, contributing to traits that are central to the public health and food safety impacts of this pathogen.
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Affiliation(s)
- Francis Muchaamba
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland,*Correspondence: Francis Muchaamba,
| | | | - Roger Stephan
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Marc J. A. Stevens
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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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: 34] [Impact Index Per Article: 17.0] [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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Muchaamba F, Eshwar AK, Stevens MJA, Stephan R, Tasara T. Different Shades of Listeria monocytogenes: Strain, Serotype, and Lineage-Based Variability in Virulence and Stress Tolerance Profiles. Front Microbiol 2022; 12:792162. [PMID: 35058906 PMCID: PMC8764371 DOI: 10.3389/fmicb.2021.792162] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 11/11/2021] [Indexed: 12/30/2022] Open
Abstract
Listeria monocytogenes is a public health and food safety challenge due to its virulence and natural stress resistance phenotypes. The variable distribution of L. monocytogenes molecular subtypes with respect to food products and processing environments and among human and animal clinical listeriosis cases is observed. Sixty-two clinical and food-associated L. monocytogenes isolates were examined through phenome and genome analysis. Virulence assessed using a zebrafish infection model revealed serotype and genotype-specific differences in pathogenicity. Strains of genetic lineage I serotype 4b and multilocus sequence type clonal complexes CC1, CC2, CC4, and CC6 grew and survived better and were more virulent than serotype 1/2a and 1/2c lineage II, CC8, and CC9 strains. Hemolysis, phospholipase activity, and lysozyme tolerance profiles were associated with the differences observed in virulence. Osmotic stress resistance evaluation revealed serotype 4b lineage I CC2 and CC4 strains as more osmotolerant, whereas serotype 1/2c lineage II CC9 strains were more osmo-sensitive than others. Variable tolerance to the widely used quaternary ammonium compound benzalkonium chloride (BC) was observed. Some outbreak and sporadic clinical case associated strains demonstrated BC tolerance, which might have contributed to their survival and transition in the food-processing environment facilitating food product contamination and ultimately outbreaks or sporadic listeriosis cases. Genome comparison uncovered various moderate differences in virulence and stress associated genes between the strains indicating that these differences in addition to gene expression regulation variations might largely be responsible for the observed virulence and stress sensitivity phenotypic differences. Overall, our study uncovered strain and genotype-dependent variation in virulence and stress resilience among clinical and food-associated L. monocytogenes isolates with potential public health risk implications. The extensive genome and phenotypic data generated provide a basis for developing improved Listeria control strategies and policies.
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Affiliation(s)
- Francis Muchaamba
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
| | - Athmanya K Eshwar
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
| | - Marc J A Stevens
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
| | - Roger Stephan
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
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8
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Listeria monocytogenes Cold Shock Proteins: Small Proteins with A Huge Impact. Microorganisms 2021; 9:microorganisms9051061. [PMID: 34068949 PMCID: PMC8155936 DOI: 10.3390/microorganisms9051061] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 01/26/2023] Open
Abstract
Listeria monocytogenes has evolved an extensive array of mechanisms for coping with stress and adapting to changing environmental conditions, ensuring its virulence phenotype expression. For this reason, L. monocytogenes has been identified as a significant food safety and public health concern. Among these adaptation systems are cold shock proteins (Csps), which facilitate rapid response to stress exposure. L. monocytogenes has three highly conserved csp genes, namely, cspA, cspB, and cspD. Using a series of csp deletion mutants, it has been shown that L. monocytogenes Csps are important for biofilm formation, motility, cold, osmotic, desiccation, and oxidative stress tolerance. Moreover, they are involved in overall virulence by impacting the expression of virulence-associated phenotypes, such as hemolysis and cell invasion. It is postulated that during stress exposure, Csps function to counteract harmful effects of stress, thereby preserving cell functions, such as DNA replication, transcription and translation, ensuring survival and growth of the cell. Interestingly, it seems that Csps might suppress tolerance to some stresses as their removal resulted in increased tolerance to stresses, such as desiccation for some strains. Differences in csp roles among strains from different genetic backgrounds are apparent for desiccation tolerance and biofilm production. Additionally, hierarchical trends for the different Csps and functional redundancies were observed on their influences on stress tolerance and virulence. Overall current data suggest that Csps have a wider role in bacteria physiology than previously assumed.
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9
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Tran BM, Prabha H, Iyer A, O'Byrne C, Abee T, Poolman B. Measurement of Protein Mobility in Listeria monocytogenes Reveals a Unique Tolerance to Osmotic Stress and Temperature Dependence of Diffusion. Front Microbiol 2021; 12:640149. [PMID: 33679676 PMCID: PMC7925416 DOI: 10.3389/fmicb.2021.640149] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/21/2021] [Indexed: 11/18/2022] Open
Abstract
Protein mobility in the cytoplasm is essential for cellular functions, and slow diffusion may limit the rates of biochemical reactions in the living cell. Here, we determined the apparent lateral diffusion coefficient (DL) of GFP in Listeria monocytogenes as a function of osmotic stress, temperature, and media composition. We find that DL is much less affected by hyperosmotic stress in L. monocytogenes than under similar conditions in Lactococcus lactis and Escherichia coli. We find a temperature optimum for protein diffusion in L. monocytogenes at 30°C, which deviates from predicted trends from the generalized Stokes-Einstein equation under dilute conditions and suggests that the structure of the cytoplasm and macromolecular crowding vary as a function of temperature. The turgor pressure of L. monocytogenes is comparable to other Gram-positive bacteria like Bacillus subtilis and L. lactis but higher in a knockout strain lacking the stress-inducible sigma factor SigB. We discuss these findings in the context of how L. monocytogenes survives during environmental transmission and interaction with the human host.
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Affiliation(s)
- Buu Minh Tran
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Haritha Prabha
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Aditya Iyer
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Conor O'Byrne
- School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Tjakko Abee
- Laboratory of Food Microbiology, Wageningen University Research, Wageningen, Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
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Matereke LT, Okoh AI. Listeria monocytogenes Virulence, Antimicrobial Resistance and Environmental Persistence: A Review. Pathogens 2020; 9:E528. [PMID: 32629911 PMCID: PMC7400505 DOI: 10.3390/pathogens9070528] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/06/2020] [Accepted: 06/20/2020] [Indexed: 12/23/2022] Open
Abstract
Listeria monocytogenes is a ubiquitous opportunistic pathogen responsible for the well-known listeriosis disease. This bacterium has become a common contaminant of food, threatening the food processing industry. Once consumed, the pathogen is capable of traversing epithelial barriers, cellular invasion, and intracellular replication through the modulation of virulence factors such as internalins and haemolysins. Mobile genetic elements (plasmids and transposons) and other sophisticated mechanisms are thought to contribute to the increasing antimicrobial resistance of L. monocytogenes. The environmental persistence of the pathogen is aided by its ability to withstand environmental stresses such as acidity, cold stress, osmotic stress, and oxidative stress. This review seeks to give an insight into L. monocytogenes biology, with emphasis on its virulence factors, antimicrobial resistance, and adaptations to environmental stresses.
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Affiliation(s)
- Lavious Tapiwa Matereke
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa
| | - Anthony Ifeanyi Okoh
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa
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Activity and Metabolic Versatility of Complete Ammonia Oxidizers in Full-Scale Wastewater Treatment Systems. mBio 2020; 11:mBio.03175-19. [PMID: 32184251 PMCID: PMC7078480 DOI: 10.1128/mbio.03175-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The discovery of comammox in the genus Nitrospira changes our perception of nitrification. However, genomes of comammox organisms have not been acquired from full-scale WWTPs, and very little is known about their survival strategies and potential metabolisms in complex wastewater treatment systems. Here, four comammox metagenome-assembled genomes and metatranscriptomic data sets were retrieved from two full-scale WWTPs. Their impressive and—among nitrifiers—unsurpassed ecophysiological versatility could make comammox Nitrospira an interesting target for optimizing nitrification in current and future bioreactor configurations. The recent discovery of complete ammonia oxidizers (comammox) contradicts the paradigm that chemolithoautotrophic nitrification is always catalyzed by two different microorganisms. However, our knowledge of the survival strategies of comammox in complex ecosystems, such as full-scale wastewater treatment plants (WWTPs), remains limited. Analyses of genomes and in situ transcriptomes of four comammox organisms from two full-scale WWTPs revealed that comammox were active and showed a surprisingly high metabolic versatility. A gene cluster for the utilization of urea and a gene encoding cyanase suggest that comammox may use diverse organic nitrogen compounds in addition to free ammonia as the substrates. The comammox organisms also encoded the genomic potential for multiple alternative energy metabolisms, including respiration with hydrogen, formate, and sulfite as electron donors. Pathways for the biosynthesis and degradation of polyphosphate, glycogen, and polyhydroxyalkanoates as intracellular storage compounds likely help comammox survive unfavorable conditions and facilitate switches between lifestyles in fluctuating environments. One of the comammox strains acquired from the anaerobic tank encoded and transcribed genes involved in homoacetate fermentation or in the utilization of exogenous acetate, both pathways being unexpected in a nitrifying bacterium. Surprisingly, this strain also encoded a respiratory nitrate reductase which has not yet been found in any other Nitrospira genome and might confer a selective advantage to this strain over other Nitrospira strains in anoxic conditions.
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Xia JM, Hu XM, Huang CH, Yu LB, Xu RF, Tang XX, Lin DH. Metabolic profiling of cold adaptation of a deep-sea psychrotolerant Microbacterium sediminis to prolonged low temperature under high hydrostatic pressure. Appl Microbiol Biotechnol 2019; 104:277-289. [PMID: 31728583 DOI: 10.1007/s00253-019-10134-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/30/2019] [Accepted: 09/08/2019] [Indexed: 12/01/2022]
Abstract
The most wide-spread "hostile" environmental factor for marine microorganisms is low temperature, which is usually accompanied by high hydrostatic pressure (HHP). Metabolic mechanisms of marine microorganisms adapting to prolonged low temperature under HHP remain to be clarified. To reveal the underlying metabolic mechanisms, we performed NMR-based metabolomic analysis of aqueous extracts derived from a psychrotolerant Microbacterium sediminis YLB-01, which was isolated from deep-sea sediment and possess great biotechnology potentials. The YLB-01 cells were firstly cultivated at the optimal condition (28 °C, 0.1 MPa) for either 18 h (logarithmic phase) or 24 h (stationary phase), then continually cultivated at either 28 °C or 4 °C under HHP (30 MPa) for 7 days. The cells cultivated at low temperature, which experienced cold stress, were distinctly distinguished from those at normal temperature. Cold stress primarily induced metabolic changes in amino acid metabolism and carbohydrate metabolism. Furthermore, the logarithmic and stationary phase cells cultivated at low temperature exhibited distinct metabolic discrimination, which was mostly reflected in the significantly disturbed carbohydrate metabolism. The logarithmic phase cells displayed suppressed TCA cycle, while the stationary phase cells showed decreased pyruvate and increased lactate. In addition, we performed transcriptome analysis for the stationary phase cells to support the metabolomic analysis. Our results suggest that the cold adaptation of the psychrotroph YLB-01 is closely associated with profoundly altered amino acid metabolism and carbohydrate metabolism. Our work provides a mechanistic understanding of the metabolic adaptation of marine psychrotrophs to prolonged low temperature under HHP.
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Affiliation(s)
- Jin-Mei Xia
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, 184 Daxue Road, Xiamen, 361005, China
| | - Xiao-Min Hu
- College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Xiamen University, Xiamen, 361005, China
| | - Cai-Hua Huang
- Research and Communication Center of Exercise and Health, Xiamen University of Technology, Xiamen, 361024, China
| | - Li-Bo Yu
- China Ocean Sample Respository (Biology), 184 Daxue Road, Xiamen, 361005, China
| | - Ru-Fang Xu
- China Ocean Sample Respository (Biology), 184 Daxue Road, Xiamen, 361005, China
| | - Xi-Xiang Tang
- China Ocean Sample Respository (Biology), 184 Daxue Road, Xiamen, 361005, China.
| | - Dong-Hai Lin
- College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Xiamen University, Xiamen, 361005, China.
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13
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Santos T, Viala D, Chambon C, Esbelin J, Hébraud M. Listeria monocytogenes Biofilm Adaptation to Different Temperatures Seen Through Shotgun Proteomics. Front Nutr 2019; 6:89. [PMID: 31259174 PMCID: PMC6587611 DOI: 10.3389/fnut.2019.00089] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/24/2019] [Indexed: 12/16/2022] Open
Abstract
Listeria monocytogenes is a foodborne pathogen that can cause invasive severe human illness (listeriosis) in susceptible patients. Most human listeriosis cases appear to be caused by consumption of refrigerated ready-to-eat foods. Although initial contamination levels in foods are usually low, the ability of these bacteria to survive and multiply at low temperatures allows it to reach levels high enough to cause disease. This study explores the set of proteins that might have an association with L. monocytogenes adaptation to different temperatures. Cultures were grown in biofilm, the most widespread mode of growth in natural and industrial realms. Protein extractions were performed from three different growth temperatures (10, 25, and 37°C) and two growth phases (early stage and mature biofilm). L. monocytogenes subproteomes were targeted using three extraction methods: trypsin-enzymatic shaving, biotin-labeling and cell fractionation. The different subproteomes obtained were separated and analyzed by shotgun proteomics using high-performance liquid chromatography combined with tandem mass spectrometry (LC-OrbiTrap LTQVelos, ThermoFisher Scientific). A total of 141 (biotinylation), 98 (shaving) and 910 (fractionation) proteins were identified. Throughout the 920 unique proteins identified, many are connected to basic cell functions, but some are linked with thermoregulation. We observed some noteworthy protein abundance shifts associated with the major adaptation to cold mechanisms present in L. monocytogenes, namely: the role of ribosomes and the stressosome with a higher abundance of the general stress protein Ctc (Rl25) and the general stress transcription factor sigma B (σB), changes in cell fluidity and motility seen by higher levels of foldase protein PrsA2 and flagellin (FlaA), the uptake of osmolytes with a higher abundance of glycine betaine (GbuB) and carnitine transporters (OpucA), and the relevance of the overexpression of chaperone proteins such as cold shock proteins (CspLA and Dps). As for 37°C, we observed a significantly higher percentage of proteins associated with transcriptional or translational activity present in higher abundance upon comparison with the colder settings. These contrasts of protein expression throughout several conditions will enrich databases and help to model the regulatory circuitry that drives adaptation of L. monocytogenes to environments.
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Affiliation(s)
- Tiago Santos
- Université Clermont Auvergne, INRA, UMR Microbiologie Environnement Digestif Santé (MEDiS), Saint-Genès-Champanelle, France
| | - Didier Viala
- INRA, Plateforme d'Exploration du Métabolisme, Composante Protéomique (PFEMcp), Saint-Genès-Champanelle, France
| | - Christophe Chambon
- INRA, Plateforme d'Exploration du Métabolisme, Composante Protéomique (PFEMcp), Saint-Genès-Champanelle, France
| | - Julia Esbelin
- Université Clermont Auvergne, INRA, UMR Microbiologie Environnement Digestif Santé (MEDiS), Saint-Genès-Champanelle, France
| | - Michel Hébraud
- Université Clermont Auvergne, INRA, UMR Microbiologie Environnement Digestif Santé (MEDiS), Saint-Genès-Champanelle, France
- INRA, Plateforme d'Exploration du Métabolisme, Composante Protéomique (PFEMcp), Saint-Genès-Champanelle, France
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Long X, Wang D, Zou Y, Tian J, Tian Y, Liao X. Glycine betaine enhances biodegradation of phenol in high saline environments by the halophilic strain Oceanobacillussp. PT-20. RSC Adv 2019; 9:29205-29216. [PMID: 35528440 PMCID: PMC9071815 DOI: 10.1039/c9ra05163e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/11/2019] [Indexed: 11/21/2022] Open
Abstract
Glycine betaine enhanced the biodegradation of phenol by halophilic strain PT-20 in high salinity conditions.
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Affiliation(s)
- Xiufeng Long
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
| | - Denggang Wang
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering
- South China University of Technology
- Guangzhou 510006
- PR China
| | - Yuqi Zou
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
| | - Jiewei Tian
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
| | - Yongqiang Tian
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
- National Engineering Laboratory for Clean Technology of Leather Manufacture
| | - Xuepin Liao
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
- National Engineering Laboratory for Clean Technology of Leather Manufacture
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15
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Wallace N, Rinehart E, Sun Y. Stimulating Respiratory Activity Primes Anaerobically Grown Listeria monocytogenes for Subsequent Intracellular Infections. Pathogens 2018; 7:E96. [PMID: 30544815 PMCID: PMC6313316 DOI: 10.3390/pathogens7040096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/30/2018] [Accepted: 12/05/2018] [Indexed: 11/25/2022] Open
Abstract
Listeria monocytogenes (L. monocytogenes) is a Gram-positive, enteric pathogen and the causative agent of listeriosis. During transition through the gastrointestinal tract, L. monocytogenes routinely encounters suboxic conditions. However, how the exposure to the low oxygen environment affects subsequent pathogenesis is not completely understood. Our lab previously reported that anaerobically grown L. monocytogenes exhibited an intracellular growth defect in macrophages even though the infection took place under aerobic conditions. This phenotype suggests that prior growth conditions have a prolonged effect on the outcome of subsequent intracellular infection. In this study, to further investigate the mechanisms that contribute to the compromised intracellular growth after anaerobic exposure, we hypothesized that the lack of respiratory activity under anaerobic conditions prevented anaerobically grown L. monocytogenes to establish subsequent intracellular growth under aerobic conditions. To test this hypothesis, respiratory activity in anaerobically grown L. monocytogenes was stimulated by exogenous fumarate and subsequent intracellular pathogenesis was assessed. The results showed that fumarate supplementation significantly increased the respiratory activity of anaerobically grown L. monocytogenes and rescued the subsequent intracellular growth defect, likely through promoting the production of listeriolysin O, phagosomal escape, and cell-cell spread. This study highlights the importance of respiratory activity in L. monocytogenes in modulating the outcome of subsequent intracellular infections.
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Affiliation(s)
- Nathan Wallace
- Department of Biology, University of Dayton, Dayton, OH 45469, USA.
| | - Erica Rinehart
- Department of Biology, University of Dayton, Dayton, OH 45469, USA.
| | - Yvonne Sun
- Department of Biology, University of Dayton, Dayton, OH 45469, USA.
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16
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Bucur FI, Grigore-Gurgu L, Crauwels P, Riedel CU, Nicolau AI. Resistance of Listeria monocytogenes to Stress Conditions Encountered in Food and Food Processing Environments. Front Microbiol 2018; 9:2700. [PMID: 30555426 PMCID: PMC6282059 DOI: 10.3389/fmicb.2018.02700] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/23/2018] [Indexed: 12/17/2022] Open
Abstract
Listeria monocytogenes is a human food-borne facultative intracellular pathogen that is resistant to a wide range of stress conditions. As a consequence, L. monocytogenes is extremely difficult to control along the entire food chain from production to storage and consumption. Frequent and recent outbreaks of L. monocytogenes infections illustrate that current measures of decontamination and preservation are suboptimal to control L. monocytogenes in food. In order to develop efficient measures to prevent contamination during processing and control growth during storage of food it is crucial to understand the mechanisms utilized by L. monocytogenes to tolerate the stress conditions in food matrices and food processing environments. Food-related stress conditions encountered by L. monocytogenes along the food chain are acidity, oxidative and osmotic stress, low or high temperatures, presence of bacteriocins and other preserving additives, and stresses as a consequence of applying alternative decontamination and preservation technologies such high hydrostatic pressure, pulsed and continuous UV light, pulsed electric fields (PEF). This review is aimed at providing a summary of the current knowledge on the response of L. monocytogenes toward these stresses and the mechanisms of stress resistance employed by this important food-borne bacterium. Circumstances when L. monocytogenes cells become more sensitive or more resistant are mentioned and existence of a cross-resistance when multiple stresses are present is pointed out.
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Affiliation(s)
- Florentina Ionela Bucur
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Leontina Grigore-Gurgu
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Peter Crauwels
- Institute of Microbiology and Biotechnology, Ulm University, Ulm, Germany
| | | | - Anca Ioana Nicolau
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
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Jacques F, Rippa S, Perrin Y. Physiology of L-carnitine in plants in light of the knowledge in animals and microorganisms. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 274:432-440. [PMID: 30080631 DOI: 10.1016/j.plantsci.2018.06.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/04/2018] [Accepted: 06/19/2018] [Indexed: 05/24/2023]
Abstract
L-carnitine is present in all living kingdoms where it acts in diverse physiological processes. It is involved in lipid metabolism in animals and yeasts, notably as an essential cofactor of fatty acid intracellular trafficking. Its physiological significance is poorly understood in plants, but L-carnitine may be linked to fatty acid metabolism among other roles. Indeed, carnitine transferases activities and acylcarnitines are measured in plant tissues. Current knowledge of fatty acid trafficking in plants rules out acylcarnitines as intermediates of the peroxisomal and mitochondrial fatty acid metabolism, unlike in animals and yeasts. Instead, acylcarnitines could be involved in plastidial exportation of de novo fatty acid, or importation of fatty acids into the ER, for synthesis of specific glycerolipids. L-carnitine also contributes to cellular maintenance though antioxidant and osmolyte properties in animals and microbes. Recent data indicate similar features in plants, together with modulation of signaling pathways. The biosynthesis of L-carnitine in the plant cell shares similar precursors as in the animal and yeast cells. The elucidation of the biosynthesis pathway of L-carnitine, and the identification of the enzymes involved, is today essential to progress further in the comprehension of its biological significance in plants.
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Affiliation(s)
- Florian Jacques
- Sorbonne Universités, Université de Technologie de Compiègne, UMR CNRS 7025 Enzyme and Cell Engineering Laboratory, Rue Roger Couttolenc, CS, 60319, 60203, Compiègne Cedex, France.
| | - Sonia Rippa
- Sorbonne Universités, Université de Technologie de Compiègne, UMR CNRS 7025 Enzyme and Cell Engineering Laboratory, Rue Roger Couttolenc, CS, 60319, 60203, Compiègne Cedex, France.
| | - Yolande Perrin
- Sorbonne Universités, Université de Technologie de Compiègne, UMR CNRS 7025 Enzyme and Cell Engineering Laboratory, Rue Roger Couttolenc, CS, 60319, 60203, Compiègne Cedex, France.
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18
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Ghonimy A, Zhang DM, Farouk MH, Wang Q. The Impact of Carnitine on Dietary Fiber and Gut Bacteria Metabolism and Their Mutual Interaction in Monogastrics. Int J Mol Sci 2018; 19:E1008. [PMID: 29597260 PMCID: PMC5979481 DOI: 10.3390/ijms19041008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/06/2018] [Accepted: 03/21/2018] [Indexed: 12/20/2022] Open
Abstract
Carnitine has vital roles in the endogenous metabolism of short chain fatty acids. It can protect and support gut microbial species, and some dietary fibers can reduce the available iron involved in the bioactivity of carnitine. There is also an antagonistic relationship between high microbial populations and carnitine bioavailability. This review shows the interactions between carnitine and gut microbial composition. It also elucidates the role of carnitine bacterial metabolism, mitochondrial function, fiber fermentability, and short chain fatty acids (SCFAs).
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Affiliation(s)
- Abdallah Ghonimy
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Dong Ming Zhang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
- Tonghua Normal University, Tonghua 134000, China.
| | - Mohammed Hamdy Farouk
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
- Department of Animal Production, Faculty of Agriculture, Al-Azhar University, Cairo 11884, Egypt.
| | - Qiuju Wang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
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19
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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: 149] [Impact Index Per Article: 24.8] [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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20
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Hingston P, Chen J, Allen K, Truelstrup Hansen L, Wang S. Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes. PLoS One 2017; 12:e0180123. [PMID: 28662112 PMCID: PMC5491136 DOI: 10.1371/journal.pone.0180123] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/11/2017] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA) profiling to characterize the bacterium's cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more genes (1.3×) were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431) and magnitude (>1,000-fold) of differentially expressed genes (>2-fold, p<0.05) in response to cold. A core set of 22 genes was upregulated at all growth phases, including nine genes required for branched-chain fatty acid (BCFA) synthesis, the osmolyte transporter genes opuCBCD, and the internalin A and D genes. Genes suppressed at 4°C were largely associated with cobalamin (B12) biosynthesis or the production/export of cell wall components. Antisense transcription accounted for up to 1.6% of total mapped reads with higher levels (2.5×) observed at 4°C than 20°C. The greatest number of upregulated antisense transcripts at 4°C occurred in early lag phase, however, at both temperatures, antisense expression levels were highest in late stationary-phase cells. Cold-induced FA membrane changes included a 15% increase in the proportion of BCFAs and a 15% transient increase in unsaturated FAs between lag and exponential phase. These increases probably reduced the membrane phase transition temperature until optimal levels of BCFAs could be produced. Collectively, this research provides new information regarding cold-induced membrane composition changes in L. monocytogenes, the growth-phase dependency of its cold-stress regulon, and the active roles of antisense transcripts in regulating its cold stress response.
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Affiliation(s)
- Patricia Hingston
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica Chen
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevin Allen
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Siyun Wang
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
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21
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Comparative genomic analysis reveals the environmental impacts on two Arcticibacter strains including sixteen Sphingobacteriaceae species. Sci Rep 2017; 7:2055. [PMID: 28515455 PMCID: PMC5435697 DOI: 10.1038/s41598-017-02191-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/27/2017] [Indexed: 01/30/2023] Open
Abstract
How the genomic diversity of species is driven by geographical isolation and environmental factors are not well understood for cold environments. Here, the environmental stress responses of two phylogenetically close Arcticibacter strains, A. eurypsychrophilus MJ9-5 and A. svalbardensis MN12-7, isolated from a Tibetan Plateau glacier and Svalbard soil, were analyzed. The comparative genomic analysis was performed with sixteen other related Sphingobacteriaceae species. Analyses of the relationships between growth temperature and genome composition, cold and heat shock genes showed that genomic adaption characteristics were more obvious when the strains were grouped by their upper limit in growth temperature, rather than by their minimal or optimal growth temperatures for Sphingobacteriaceae species. The very divergent genetic distance of genome fractions assigned to the functions of ‘secondary metabolism’, ‘dormancy and sporulation’ and ‘metabolism of aromatic compounds’ indicated the heterogeneous evolution of genes under different environmental pressures of the Sphingobacteriaceae species. The greatest differences between strains MJ9-5 and MN12-7 occurred in the genes devoted to the CRISPRs, osmotic adaption and metabolism of monosaccharides, nitrogen and aromatic compounds. These distinctions corresponded to two different environmental pressures, salinity and nutritional level, in the glacier ice and Svalbard soil environments.
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22
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Lobete MM, Noriega E, Batalha MA, de Beurme S, Van de Voorde I, Van Impe JF. Effect of tagatose on growth dynamics of Salmonella Typhimurium and Listeria monocytogenes in media with different levels of structural complexity and in UHT skimmed milk. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.05.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Stevia-based sweeteners as a promising alternative to table sugar: The effect on Listeria monocytogenes and Salmonella Typhimurium growth dynamics. Int J Food Microbiol 2017; 245:38-52. [DOI: 10.1016/j.ijfoodmicro.2017.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 12/21/2016] [Accepted: 01/17/2017] [Indexed: 11/22/2022]
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24
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Crystal Structure of the Substrate-Binding Domain from Listeria monocytogenes Bile-Resistance Determinant BilE. CRYSTALS 2016. [DOI: 10.3390/cryst6120162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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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: 117] [Impact Index Per Article: 14.6] [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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Jarvis NA, O'Bryan CA, Ricke SC, Johnson MG, Crandall PG. A review of minimal and defined media for growth of Listeria monocytogenes. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Seel W, Derichs J, Lipski A. Increased Biomass Production by Mesophilic Food-Associated Bacteria through Lowering the Growth Temperature from 30°C to 10°C. Appl Environ Microbiol 2016; 82:3754-3764. [PMID: 27084015 PMCID: PMC4907174 DOI: 10.1128/aem.00211-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/11/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Five isolates from chilled food and refrigerator inner surfaces and closely related reference strains of the species Escherichia coli, Listeria monocytogenes, Staphylococcus xylosus, Bacillus cereus, Pedobacter nutrimenti, and Pedobacter panaciterrae were tested for the effect of growth temperature (30°C and 10°C) on biomass formation. Growth was monitored via optical density, and biomass formation was measured at the early stationary phase based on the following parameters in complex and defined media: viable cell count, total cell count, cell dry weight, whole-cell protein content, and cell morphology. According to the lack of growth at 1°C, all strains were assigned to the thermal class of mesophiles. Glucose and ammonium consumption related to cell yield were analyzed in defined media. Except for the protein content, temperature had a significant (t test, P < 0.05) effect on all biomass formation parameters for each strain. The results show a significant difference between the isolates and the related reference strains. Isolates achieved an increase in biomass production between 20% and 110% at the 10°C temperature, which is 15 to 25°C lower than their maximum growth rate temperatures. In contrast, reference strains showed a maximum increase of only about 25%, and some reference strains showed no increase or a decrease of approximately 25%. As expected, growth rates for all strains were higher at 30°C than at 10°C, while biomass production for isolates was higher at 10°C than at 30°C. In contrast, the reference strains showed similar growth yields at the two temperatures. This also demonstrates for mesophilic bacterial strains more efficient nutrient assimilation during growth at low temperatures. Until now, this characteristic was attributed only to psychrophilic microorganisms. IMPORTANCE For several psychrophilic species, increased biomass formation was described at temperatures lower than optimum growth temperatures, which are defined by the highest growth rate. This work shows increased biomass formation at low growth temperatures for mesophilic isolates. A comparison with closely related reference strains from culture collections showed a significantly smaller increase or no increase in biomass formation. This indicates a loss of specific adaptive mechanisms (e.g., cold adaptation) for mesophiles during long-term cultivation. The increased biomass production for mesophiles under low-temperature conditions opens new avenues for a more efficient biotechnological transformation of nutrients to microbial biomass. These findings may also be important for risk assessment of cooled foods since risk potential is often correlated with the cell numbers present in food samples.
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Affiliation(s)
- Waldemar Seel
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Ernährungs- und Lebensmittelwissenschaften, Abteilung Lebensmittelmikrobiologie und -hygiene, Bonn, Germany
| | - Julia Derichs
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Ernährungs- und Lebensmittelwissenschaften, Abteilung Lebensmittelmikrobiologie und -hygiene, Bonn, Germany
| | - André Lipski
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Ernährungs- und Lebensmittelwissenschaften, Abteilung Lebensmittelmikrobiologie und -hygiene, Bonn, Germany
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28
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Teixeira JS, Maier MB, Miller P, Gänzle MG, McMullen LM. The effect of growth temperature, process temperature, and sodium chloride on the high-pressure inactivation of Listeria monocytogenes on ham. Eur Food Res Technol 2016. [DOI: 10.1007/s00217-016-2700-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cordero N, Maza F, Navea-Perez H, Aravena A, Marquez-Fontt B, Navarrete P, Figueroa G, González M, Latorre M, Reyes-Jara A. Different Transcriptional Responses from Slow and Fast Growth Rate Strains of Listeria monocytogenes Adapted to Low Temperature. Front Microbiol 2016; 7:229. [PMID: 26973610 PMCID: PMC4772535 DOI: 10.3389/fmicb.2016.00229] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/12/2016] [Indexed: 01/12/2023] Open
Abstract
Listeria monocytogenes has become one of the principal foodborne pathogens worldwide. The capacity of this bacterium to grow at low temperatures has opened an interesting field of study in terms of the identification and classification of new strains of L. monocytogenes with different growth capacities at low temperatures. We determined the growth rate at 8°C of 110 strains of L. monocytogenes isolated from different food matrices. We identified a group of slow and fast strains according to their growth rate at 8°C and performed a global transcriptomic assay in strains previously adapted to low temperature. We then identified shared and specific transcriptional mechanisms, metabolic and cellular processes of both groups; bacterial motility was the principal process capable of differentiating the adaptation capacity of L. monocytogenes strains with different ranges of tolerance to low temperatures. Strains belonging to the fast group were less motile, which may allow these strains to achieve a greater rate of proliferation at low temperature.
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Affiliation(s)
- Ninoska Cordero
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Felipe Maza
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Helen Navea-Perez
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Andrés Aravena
- Department of Molecular Biology and Genetics, Istanbul University Istanbul, Turkey
| | - Bárbara Marquez-Fontt
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Paola Navarrete
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Guillermo Figueroa
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
| | - Mauricio González
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Center for Genome Regulation (Fondap 15090007), Universidad de ChileSantiago, Chile
| | - Mauricio Latorre
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de ChileSantiago, Chile; Center for Genome Regulation (Fondap 15090007), Universidad de ChileSantiago, Chile; Mathomics, Center for Mathematical Modeling, Universidad de ChileSantiago, Chile
| | - Angélica Reyes-Jara
- Laboratorio de Microbiología y Probióticos, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile Santiago, Chile
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30
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Vermassen A, Dordet-Frisoni E, de La Foye A, Micheau P, Laroute V, Leroy S, Talon R. Adaptation of Staphylococcus xylosus to Nutrients and Osmotic Stress in a Salted Meat Model. Front Microbiol 2016; 7:87. [PMID: 26903967 PMCID: PMC4742526 DOI: 10.3389/fmicb.2016.00087] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/18/2016] [Indexed: 11/17/2022] Open
Abstract
Staphylococcus xylosus is commonly used as starter culture for meat fermentation. Its technological properties are mainly characterized in vitro, but the molecular mechanisms for its adaptation to meat remain unknown. A global transcriptomic approach was used to determine these mechanisms. S. xylosus modulated the expression of about 40-50% of the total genes during its growth and survival in the meat model. The expression of many genes involved in DNA machinery and cell division, but also in cell lysis, was up-regulated. Considering that the S. xylosus population remained almost stable between 24 and 72 h of incubation, our results suggest a balance between cell division and cell lysis in the meat model. The expression of many genes encoding enzymes involved in glucose and lactate catabolism was up-regulated and revealed that glucose and lactate were used simultaneously. S. xylosus seemed to adapt to anaerobic conditions as revealed by the overexpression of two regulatory systems and several genes encoding cofactors required for respiration. In parallel, genes encoding transport of peptides and peptidases that could furnish amino acids were up-regulated and thus concomitantly a lot of genes involved in amino acid synthesis were down-regulated. Several genes involved in glutamate homeostasis were up-regulated. Finally, S. xylosus responded to the osmotic stress generated by salt added to the meat model by overexpressing genes involved in transport and synthesis of osmoprotectants, and Na(+) and H(+) extrusion.
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Affiliation(s)
| | | | - Anne de La Foye
- INRA, Plateforme d'Exploration du MétabolismeSaint-Genès Champanelle, France
| | - Pierre Micheau
- INRA, UR454 MicrobiologieSaint-Genès Champanelle, France
| | - Valérie Laroute
- Université de Toulouse, INSA, UPS, INP, LISBPToulouse, France
| | - Sabine Leroy
- INRA, UR454 MicrobiologieSaint-Genès Champanelle, France
| | - Régine Talon
- INRA, UR454 MicrobiologieSaint-Genès Champanelle, France
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31
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Roumiantseva ML, Muntyan VS. Root nodule bacteria Sinorhizobium meliloti: Tolerance to salinity and bacterial genetic determinants. Microbiology (Reading) 2015. [DOI: 10.1134/s0026261715030170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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32
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Meadows JA, Wargo MJ. Carnitine in bacterial physiology and metabolism. MICROBIOLOGY (READING, ENGLAND) 2015; 161:1161-74. [PMID: 25787873 PMCID: PMC4635513 DOI: 10.1099/mic.0.000080] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/17/2015] [Indexed: 12/23/2022]
Abstract
Carnitine is a quaternary amine compound found at high concentration in animal tissues, particularly muscle, and is most well studied for its contribution to fatty acid transport into mitochondria. In bacteria, carnitine is an important osmoprotectant, and can also enhance thermotolerance, cryotolerance and barotolerance. Carnitine can be transported into the cell or acquired from metabolic precursors, where it can serve directly as a compatible solute for stress protection or be metabolized through one of a few distinct pathways as a nutrient source. In this review, we summarize what is known about carnitine physiology and metabolism in bacteria. In particular, recent advances in the aerobic and anaerobic metabolic pathways as well as the use of carnitine as an electron acceptor have addressed some long-standing questions in the field.
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Affiliation(s)
- Jamie A. Meadows
- Department of Microbiology and Molecular Genetics, University of Vermont College of Medicine, 95 Carrigan Drive, Burlington, VT, 05405, USA
| | - Matthew J. Wargo
- Department of Microbiology and Molecular Genetics, University of Vermont College of Medicine, 95 Carrigan Drive, Burlington, VT, 05405, USA
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33
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Tanizawa Y, Tohno M, Kaminuma E, Nakamura Y, Arita M. Complete genome sequence and analysis of Lactobacillus hokkaidonensis LOOC260(T), a psychrotrophic lactic acid bacterium isolated from silage. BMC Genomics 2015; 16:240. [PMID: 25879859 PMCID: PMC4377027 DOI: 10.1186/s12864-015-1435-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/06/2015] [Indexed: 01/19/2023] Open
Abstract
Background Lactobacillus hokkaidonensis is an obligate heterofermentative lactic acid bacterium, which is isolated from Timothy grass silage in Hokkaido, a subarctic region of Japan. This bacterium is expected to be useful as a silage starter culture in cold regions because of its remarkable psychrotolerance; it can grow at temperatures as low as 4°C. To elucidate its genetic background, particularly in relation to the source of psychrotolerance, we constructed the complete genome sequence of L. hokkaidonensis LOOC260T using PacBio single-molecule real-time sequencing technology. Results The genome of LOOC260T comprises one circular chromosome (2.28 Mbp) and two circular plasmids: pLOOC260-1 (81.6 kbp) and pLOOC260-2 (41.0 kbp). We identified diverse mobile genetic elements, such as prophages, integrated and conjugative elements, and conjugative plasmids, which may reflect adaptation to plant-associated niches. Comparative genome analysis also detected unique genomic features, such as genes involved in pentose assimilation and NADPH generation. Conclusions This is the first complete genome in the L. vaccinostercus group, which is poorly characterized, so the genomic information obtained in this study provides insight into the genetics and evolution of this group. We also found several factors that may contribute to the ability of L. hokkaidonensis to grow at cold temperatures. The results of this study will facilitate further investigation for the cold-tolerance mechanism of L. hokkaidonensis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1435-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yasuhiro Tanizawa
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8561, Japan. .,Center for Information Biology, National Institute of Genetics, Shizuoka, 411-8540, Japan.
| | - Masanori Tohno
- National Agriculture and Food Research Organization, National Institute of Livestock and Grassland Science, Tochigi, 329-2793, Japan.
| | - Eli Kaminuma
- Center for Information Biology, National Institute of Genetics, Shizuoka, 411-8540, Japan.
| | - Yasukazu Nakamura
- Center for Information Biology, National Institute of Genetics, Shizuoka, 411-8540, Japan.
| | - Masanori Arita
- Center for Information Biology, National Institute of Genetics, Shizuoka, 411-8540, Japan. .,RIKEN Center for Sustainable Resource Science, Kanagawa, 230-0045, Japan.
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34
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Burall LS, Simpson AC, Chou L, Laksanalamai P, Datta AR. A novel gene, lstC, of Listeria monocytogenes is implicated in high salt tolerance. Food Microbiol 2015; 48:72-82. [PMID: 25790994 DOI: 10.1016/j.fm.2014.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 12/01/2014] [Accepted: 12/16/2014] [Indexed: 01/08/2023]
Abstract
Listeria monocytogenes, causative agent of human listeriosis, has been isolated from a wide variety of foods including deli meats, soft cheeses, cantaloupes, sprouts and canned mushrooms. Standard control measures for restricting microbial growth such as refrigeration and high salt are often inadequate as L. monocytogenes grows quite well in these environments. In an effort to better understand the genetic and physiological basis by which L. monocytogenes circumvents these controls, a transposon library of L. monocytogenes was screened for changes in their ability to grow in 7% NaCl and/ or at 5 °C. This work identified a transposon insertion upstream of an operon, here named lstABC, that led to a reduction in growth in 7% NaCl. In-frame deletion studies identified lstC which codes for a GNAT-acetyltransferase being responsible for the phenotype. Transcriptomic and RT-PCR analyses identified nine genes that were upregulated in the presence of high salt in the ΔlstC mutant. Further analysis of lstC and the genes affected by ΔlstC is needed to understand LstC's role in salt tolerance.
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Affiliation(s)
- Laurel S Burall
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Alexandra C Simpson
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Luoth Chou
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Pongpan Laksanalamai
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Atin R Datta
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA.
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35
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Broy S, Chen C, Hoffmann T, Brock NL, Nau-Wagner G, Jebbar M, Smits SHJ, Dickschat JS, Bremer E. Abiotic stress protection by ecologically abundant dimethylsulfoniopropionate and its natural and synthetic derivatives: insights from Bacillus subtilis. Environ Microbiol 2014; 17:2362-78. [PMID: 25384455 DOI: 10.1111/1462-2920.12698] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/22/2014] [Accepted: 10/28/2014] [Indexed: 12/01/2022]
Abstract
Dimethylsulfoniopropionate (DMSP) is an abundant osmolyte and anti-stress compound produced primarily in marine ecosystems. After its release into the environment, microorganisms can exploit DMSP as a source of sulfur and carbon, or accumulate it as an osmoprotectant. However, import systems for this ecophysiologically important compatible solute, and its stress-protective properties for microorganisms that do not produce it are insufficiently understood. Here we address these questions using a well-characterized set of Bacillus subtilis mutants to chemically profile the influence of DMSP import on stress resistance, the osmostress-adaptive proline pool and on osmotically controlled gene expression. We included in this study the naturally occurring selenium analogue of DMSP, dimethylseleniopropionate (DMSeP), as well as a set of synthetic DMSP derivatives. We found that DMSP is not a nutrient for B. subtilis, but it serves as an excellent stress protectant against challenges conferred by sustained high salinity or lasting extremes in both low and high growth temperatures. DMSeP and synthetic DMSP derivatives retain part of these stress protective attributes, but DMSP is clearly the more effective stress protectant. We identified the promiscuous and widely distributed ABC transporter OpuC as a high-affinity uptake system not only for DMSP, but also for its natural and synthetic derivatives.
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Affiliation(s)
- Sebastian Broy
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, D-35043, Marburg, Germany
| | - Chiliang Chen
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, D-35043, Marburg, Germany.,LOEWE-Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerwein Str., D-35043, Marburg, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, D-35043, Marburg, Germany.,LOEWE-Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerwein Str., D-35043, Marburg, Germany
| | - Nelson L Brock
- Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, D-38106, Braunschweig, Germany
| | - Gabriele Nau-Wagner
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, D-35043, Marburg, Germany
| | - Mohamed Jebbar
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, D-35043, Marburg, Germany.,Laboratory of Microbiology of Extreme Environments, UMR 6197 (CNRS - Ifremer - UBO), European Institute of Marine Studies, University of West Brittany (Brest), Technopole Brest-Iroise, F-29280, Plouzané, France
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Universitäts Str. 1, D-40225, Düsseldorf, Germany
| | - Jeroen S Dickschat
- Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, D-38106, Braunschweig, Germany.,Kekule-Institute for Organic Chemistry and Biochemistry, Friedrich Wilhelms-University Bonn, Gerhard-Domagk-Str. 1, D-53121, Bonn, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, D-35043, Marburg, Germany.,LOEWE-Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerwein Str., D-35043, Marburg, Germany
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36
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Murdock L, Burke T, Coumoundouros C, Culham DE, Deutch CE, Ellinger J, Kerr CH, Plater SM, To E, Wright G, Wood JM. Analysis of strains lacking known osmolyte accumulation mechanisms reveals contributions of osmolytes and transporters to protection against abiotic stress. Appl Environ Microbiol 2014; 80:5366-78. [PMID: 24951793 PMCID: PMC4136119 DOI: 10.1128/aem.01138-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 06/17/2014] [Indexed: 11/20/2022] Open
Abstract
Osmolyte accumulation and release can protect cells from abiotic stresses. In Escherichia coli, known mechanisms mediate osmotic stress-induced accumulation of K(+) glutamate, trehalose, or zwitterions like glycine betaine. Previous observations suggested that additional osmolyte accumulation mechanisms (OAMs) exist and their impacts may be abiotic stress specific. Derivatives of the uropathogenic strain CFT073 and the laboratory strain MG1655 lacking known OAMs were created. CFT073 grew without osmoprotectants in minimal medium with up to 0.9 M NaCl. CFT073 and its OAM-deficient derivative grew equally well in high- and low-osmolality urine pools. Urine-grown bacteria did not accumulate large amounts of known or novel osmolytes. Thus, CFT073 showed unusual osmotolerance and did not require osmolyte accumulation to grow in urine. Yeast extract and brain heart infusion stimulated growth of the OAM-deficient MG1655 derivative at high salinity. Neither known nor putative osmoprotectants did so. Glutamate and glutamine accumulated after growth with either organic mixture, and no novel osmolytes were detected. MG1655 derivatives retaining individual OAMs were created. Their abilities to mediate osmoprotection were compared at 15°C, 37°C without or with urea, and 42°C. Stress protection was not OAM specific, and variations in osmoprotectant effectiveness were similar under all conditions. Glycine betaine and dimethylsulfoniopropionate (DMSP) were the most effective. Trimethylamine-N-oxide (TMAO) was a weak osmoprotectant and a particularly effective urea protectant. The effectiveness of glycine betaine, TMAO, and proline as osmoprotectants correlated with their preferential exclusion from protein surfaces, not with their propensity to prevent protein denaturation. Thus, their effectiveness as stress protectants correlated with their ability to rehydrate the cytoplasm.
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Affiliation(s)
- Lindsay Murdock
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Tangi Burke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Chelsea Coumoundouros
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Doreen E Culham
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Charles E Deutch
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada School of Mathematical and Natural Sciences, Arizona State University at the West Campus, Phoenix, Arizona, USA
| | - James Ellinger
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Craig H Kerr
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Samantha M Plater
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Eric To
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Geordie Wright
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Janet M Wood
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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King T, Kocharunchitt C, Gobius K, Bowman JP, Ross T. Global genome response of Escherichia coli O157∶H7 Sakai during dynamic changes in growth kinetics induced by an abrupt temperature downshift. PLoS One 2014; 9:e99627. [PMID: 24926786 PMCID: PMC4057180 DOI: 10.1371/journal.pone.0099627] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 05/17/2014] [Indexed: 11/23/2022] Open
Abstract
Escherichia coli O157∶H7 is a mesophilic food-borne pathogen. We investigated the growth kinetics of E. coli O157∶H7 Sakai during an abrupt temperature downshift from 35°C to either 20°C, 17°C, 14°C or 10°C; as well as the molecular mechanisms enabling growth after cold stress upon an abrupt downshift from 35°C to 14°C in an integrated transcriptomic and proteomic analysis. All downshifts caused a lag period of growth before growth resumed at a rate typical of the post-shift temperature. Lag and generation time increased with the magnitude of the shift or with the final temperature, while relative lag time displayed little variation across the test range. Analysis of time-dependent molecular changes revealed, in keeping with a decreased growth rate at lower temperature, repression of genes and proteins involved in DNA replication, protein synthesis and carbohydrate catabolism. Consistent with cold-induced remodelling of the bacterial cell envelope, alterations occurred in the expression of genes and proteins involved in transport and binding. The RpoS regulon exhibited sustained induction confirming its importance in adaptation and growth at 14°C. The RpoE regulon was transiently induced, indicating a potential role for this extracytoplasmic stress response system in the early phase of low temperature adaptation during lag phase. Interestingly, genes previously reported to be amongst the most highly up-regulated under oxidative stress were consistently down-regulated. This comprehensive analysis provides insight into the molecular mechanisms operating during adaptation of E. coli to growth at low temperature and is relevant to its physiological state during chilling in foods, such as carcasses.
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Affiliation(s)
- Thea King
- Commonwealth Scientific and Industrial Research Organisation, Animal, Food and Health Sciences, North Ryde, New South Wales, Australia
- * E-mail:
| | - Chawalit Kocharunchitt
- Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Kari Gobius
- Commonwealth Scientific and Industrial Research Organisation, Animal, Food and Health Sciences, Werribee, Victoria, Australia
| | - John P. Bowman
- Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Tom Ross
- Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
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38
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Bashir A, Hoffmann T, Smits SHJ, Bremer E. Dimethylglycine provides salt and temperature stress protection to Bacillus subtilis. Appl Environ Microbiol 2014; 80:2773-85. [PMID: 24561588 PMCID: PMC3993278 DOI: 10.1128/aem.00078-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 02/17/2014] [Indexed: 12/13/2022] Open
Abstract
Glycine betaine is a potent osmotic and thermal stress protectant of many microorganisms. Its synthesis from glycine results in the formation of the intermediates monomethylglycine (sarcosine) and dimethylglycine (DMG), and these compounds are also produced when it is catabolized. Bacillus subtilis does not produce sarcosine or DMG, and it cannot metabolize these compounds. Here we have studied the potential of sarcosine and DMG to protect B. subtilis against osmotic, heat, and cold stress. Sarcosine, a compatible solute that possesses considerable protein-stabilizing properties, did not serve as a stress protectant of B. subtilis. DMG, on the other hand, proved to be only moderately effective as an osmotic stress protectant, but it exhibited good heat stress-relieving and excellent cold stress-relieving properties. DMG is imported into B. subtilis cells primarily under osmotic and temperature stress conditions via OpuA, a member of the ABC family of transporters. Ligand-binding studies with the extracellular solute receptor (OpuAC) of the OpuA system showed that OpuAC possesses a moderate affinity for DMG, with a Kd value of approximate 172 μM; its Kd for glycine betaine is about 26 μM. Docking studies using the crystal structures of the OpuAC protein with the sulfur analog of DMG, dimethylsulfonioacetate, as a template suggest a model of how the DMG molecule can be stably accommodated within the aromatic cage of the OpuAC ligand-binding pocket. Collectively, our data show that the ability to acquire DMG from exogenous sources under stressful environmental conditions helps the B. subtilis cell to cope with growth-restricting osmotic and temperature challenges.
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Affiliation(s)
- Abdallah Bashir
- Laboratory for Microbiology, Department of Biology, Philipps-Universität Marburg, Marburg, Germany
- Al-Azhar University—Gaza, Faculty of Science, Biology Department, Gaza
- Max Planck Institute for Terrestrial Microbiology, Emeritus Group of R. K. Thauer, Marburg, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-Universität Marburg, Marburg, Germany
- LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany
| | - Sander H. J. Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-Universität Marburg, Marburg, Germany
- LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany
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39
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Identification of genes involved in salt tolerance and symbiotic nitrogen fixation in chickpea rhizobium Mesorhizobium ciceri Ca181. Symbiosis 2013. [DOI: 10.1007/s13199-013-0264-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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40
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Global transcriptome analysis of Lactococcus garvieae strains in response to temperature. PLoS One 2013; 8:e79692. [PMID: 24223997 PMCID: PMC3817100 DOI: 10.1371/journal.pone.0079692] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 09/24/2013] [Indexed: 11/19/2022] Open
Abstract
Lactococcus garvieae is an important fish and an opportunistic human pathogen. The genomic sequences of several L. garvieae strains have been recently published, opening the possibility of global studies on the biology of this pathogen. In this study, a whole genome DNA microarray of two strains of L. garvieae was designed and validated. This DNA microarray was used to investigate the effects of growth temperature (18°C and 37°C) on the transcriptome of two clinical strains of L. garvieae that were isolated from fish (Lg8831) and from a human case of septicemia (Lg21881). The transcriptome profiles evidenced a strain-specific response to temperature, which was more evident at 18°C. Among the most significant findings, Lg8831 was found to up-regulate at 18°C several genes encoding different cold-shock and cold-induced proteins involved in an efficient adaptive response of this strain to low-temperature conditions. Another relevant result was the description, for the first time, of respiratory metabolism in L. garvieae, whose gene expression regulation was temperature-dependent in Lg21881. This study provides new insights about how environmental factors such as temperature can affect L. garvieae gene expression. These data could improve our understanding of the regulatory networks and adaptive biology of this important pathogen.
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41
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Hoffmann RF, McLernon S, Feeney A, Hill C, Sleator RD. A single point mutation in the listerial betL σ(A)-dependent promoter leads to improved osmo- and chill-tolerance and a morphological shift at elevated osmolarity. Bioengineered 2013; 4:401-7. [PMID: 23478432 PMCID: PMC3937201 DOI: 10.4161/bioe.24094] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Betaine uptake in Listeria monocytogenes is mediated by three independent transport systems, the simplest of which in genetic terms is the secondary transporter BetL. Using a random mutagenesis approach, based on the E. coli XL1 Red mutator strain, we identified a single point mutation in a putative promoter region upstream of the BetL coding region which leads to a significant increase in betL transcript levels under osmo- and chill-stress conditions and a concomitant increase in stress tolerance. Furthermore, the mutation appears to counter the heretofore unreported “twisted” cell morphology observed for L. monocytogenes grown at elevated osmolarities in tryptone soy broth.
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Affiliation(s)
- Roland F Hoffmann
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland; Department of Biological Sciences; Cork Institute of Technology; Cork, Ireland
| | - Susan McLernon
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
| | - Audrey Feeney
- Department of Biological Sciences; Cork Institute of Technology; Cork, Ireland
| | - Colin Hill
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
| | - Roy D Sleator
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland; Department of Biological Sciences; Cork Institute of Technology; Cork, Ireland
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Rippa S, Zhao Y, Merlier F, Charrier A, Perrin Y. The carnitine biosynthetic pathway in Arabidopsis thaliana shares similar features with the pathway of mammals and fungi. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 60:109-14. [PMID: 22922110 DOI: 10.1016/j.plaphy.2012.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/02/2012] [Indexed: 05/01/2023]
Abstract
Carnitine is an essential quaternary ammonium amino acid that occurs in the microbial, plant and animal kingdoms. The role and synthesis of this compound are very well documented in bacteria, fungi and mammals. On the contrary, although the presence of carnitine in plant tissue has been reported four decades ago and information about its biological implication are available, nothing is known about its synthesis in plants. We designed experiments to determine if the carnitine biosynthetic pathway in Arabidopsis thaliana is similar to the pathway in mammals and in the fungi Neurospora crassa and Candida albicans. We first checked for the presence of trimetyllysine (TML) and γ-butyrobetaine (γ-BB), two precursors of carnitine in fungi and in mammals, using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Both compounds were shown to be present in plant extracts at concentrations in the picomole range per mg of dry weight. We next synthesized deuterium-labeled TML and transferred A. thaliana seedlings on growth medium supplemented with 1 mM of the deuterated precursor. LC-ESI-MS/MS analysis of plant extracts clearly highlighted the synthesis of deuterium labeled γ-BB and labeled carnitine in deuterated-TML fed plants. The similarities between plant, fungal and mammalian pathways provide very useful information to search homologies between genomes. As a matter of fact the analysis of A. thaliana protein database provides homology for several enzymes responsible for carnitine synthesis in fungi and mammals. The study of mutants affected in the corresponding genes would be very useful to elucidate the plant carnitine biosynthetic pathway and to investigate further the role of carnitine in plant physiology.
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Affiliation(s)
- Sonia Rippa
- Génie Enzymatique et Cellulaire (GEC), UMR 6022 CNRS, Université de Technologie de Compiègne, Centre de Recherche Royallieu, BP 20529, 60205 Compiègne Cedex, France
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43
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Gomes Neto NJ, Luz IS, Honório WG, Tavares AG, de Souza EL. Rosmarinus officinalisL. essential oil and the related compound 1,8-cineole do not induce direct or cross-protection inListeria monocytogenesATCC 7644 cultivated in meat broth. Can J Microbiol 2012; 58:973-81. [DOI: 10.1139/w2012-070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Listeria monocytogenes has the capability of adapting to 1 or more antimicrobial compounds or procedures applied by the food industry to control the growth and survival of microorganisms in foods. In this study, the effects of Rosmarinus officinalis essential oil (EO) and the related compound 1,8-cineole on the inhibition of the growth and survival of L. monocytogenes ATCC 7644 were determined. The ability of the R. officinalis EO and 1,8-cineole to induce direct and cross-protection of bacteria against various stresses (lactic acid, pH 5.2; NaCl, 3 g/100 mL; high temperature, 45 °C) was also determined. At all concentrations tested (minimum inhibitory concentration (MIC), ½ MIC, and ¼ MIC), both compounds inhibited the cell viability of L. monocytogenes over 120 min of exposure. Overnight exposure of L. monocytogenes to sublethal amounts of either the R. officinalis EO or 1,8-cineole in meat broth revealed no induction of direct or cross-protection against lactic acid, NaCl, or high temperature. Similarly, cells subjected to 24 h cycles of adaptation with increasing amounts (½ MIC to 2× MIC) of the EO and 1,8-cineole showed no increase in direct tolerance, as they were able to survive in growth medium containing up to ½ MIC of either substance. These results show the antimicrobial efficacy of R. officinalis EO and 1,8-cineole for use in systems, particularly as anti-L. monocytogenes compounds.
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Affiliation(s)
- Nelson Justino Gomes Neto
- Laboratory of Food Microbiology, Department of Nutrition, Health Sciences Center, Federal University of Paraíba, João Pessoa 58051-900, Brazil
| | - Isabelle Silva Luz
- Laboratory of Food Microbiology, Department of Nutrition, Health Sciences Center, Federal University of Paraíba, João Pessoa 58051-900, Brazil
| | - Wanessa Gonçalves Honório
- Laboratory of Food Microbiology, Department of Nutrition, Health Sciences Center, Federal University of Paraíba, João Pessoa 58051-900, Brazil
| | - Adassa Gama Tavares
- Laboratory of Food Microbiology, Department of Nutrition, Health Sciences Center, Federal University of Paraíba, João Pessoa 58051-900, Brazil
| | - Evandro Leite de Souza
- Laboratory of Food Microbiology, Department of Nutrition, Health Sciences Center, Federal University of Paraíba, João Pessoa 58051-900, Brazil
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Charrier A, Rippa S, Yu A, Nguyen PJ, Renou JP, Perrin Y. The effect of carnitine on Arabidopsis development and recovery in salt stress conditions. PLANTA 2012; 235:123-135. [PMID: 21853252 DOI: 10.1007/s00425-011-1499-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 08/05/2011] [Indexed: 05/31/2023]
Abstract
Carnitine exists in all living organisms where it plays diverse roles. In animals and yeast, it is implicated in lipid metabolism and is also associated with oxidative stress tolerance. In bacteria, it is a major player in osmotic stress tolerance. We investigate the carnitine function in plants and our present work shows that carnitine enhances the development and recovery of Arabidopsis thaliana seedlings subjected to salt stress. Biological data show that exogenous carnitine supplies improve the germination and survival rates of seedlings grown on salt-enriched medium, in a manner comparable to proline. Both compounds are shown to improve seedling survival under oxidative constraint meaning that they may act on salt stress through antioxidant properties. A transcriptome analysis of seedlings treated with exogenous carnitine reveals that it modulates the expression of genes involved in water stress and abscisic acid responses. Analyses of the abscisic acid mutants, aba1-1 and abi1-1, indicate that carnitine and proline may act through a modulation of the ABA pathway.
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Affiliation(s)
- Aurélie Charrier
- Université de Technologie de Compiègne, UMR CNRS 6022 Génie Enzymatique et Cellulaire, BP 20529, 60205, Compiègne Cedex, France
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Ectoine and hydroxyectoine as protectants against osmotic and cold stress: uptake through the SigB-controlled betaine-choline- carnitine transporter-type carrier EctT from Virgibacillus pantothenticus. J Bacteriol 2011; 193:4699-708. [PMID: 21764932 DOI: 10.1128/jb.05270-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Virgibacillus pantothenticus has been shown to synthesize the compatible solute ectoine in response to high salinity or low growth temperature. We found that exogenously provided ectoine and hydroxyectoine also serve as protectants against these challenges. Transport studies with [(14)C]ectoine revealed that both types of stress induced a high-affinity ectoine uptake activity in V. pantothenticus. By using an Escherichia coli mutant defective in osmoprotectant uptake systems, a functional complementation approach for osmostress resistance in the presence of ectoine was employed to retrieve a gene encoding an ectoine transporter from V. pantothenticus. The cloned gene (ectT) encodes a protein (EctT) that is a member of the BCCT (betaine-choline-carnitine-transporter) family of carriers. Osmoprotection assays demonstrated that the EctT carrier mediates the preferential import of ectoine and hydroxyectoine but also possesses minor uptake activities for the compatible solutes proline and glycine betaine. Northern blot analysis with RNA isolated from V. pantothenticus revealed that a rise in the external osmolality or a reduction in growth temperature strongly increased the transcription of the ectT gene. Primer extension analysis demonstrated that ectT was transcribed under these conditions from a SigB-type promoter. SigB is the master regulator of the general stress regulon of bacilli and provides protection to cells against various challenges, including high salinity and low temperature. Both the synthesis of ectoine and the EctT-mediated uptake of ectoine and hydroxyectoine are triggered by the same environmental cues, high salinity and cold stress, and thereby provide, in a concerted fashion, the protection of V. pantothenticus against these challenges.
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A specialized aspartokinase enhances the biosynthesis of the osmoprotectants ectoine and hydroxyectoine in Pseudomonas stutzeri A1501. J Bacteriol 2011; 193:4456-68. [PMID: 21725014 DOI: 10.1128/jb.00345-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The compatible solutes ectoine and hydroxyectoine are widely produced by bacteria as protectants against osmotic and temperature stress. l-Aspartate-beta-semialdehyde is used as the precursor molecule for ectoine/hydroxyectoine biosynthesis that is catalyzed by the EctABCD enzymes. l-Aspartate-beta-semialdehyde is a central intermediate in different biosynthetic pathways and is produced from l-aspartate by aspartokinase (Ask) and aspartate-semialdehyde-dehydrogenase (Asd). Ask activity is typically stringently regulated by allosteric control to avoid gratuitous synthesis of aspartylphosphate. Many organisms have evolved multiple forms of aspartokinase, and feedback regulation of these specialized Ask enzymes is often adapted to the cognate biochemical pathways. The ectoine/hydroxyectoine biosynthetic genes (ectABCD) are followed in a considerable number of microorganisms by an askgene (ask_ect), suggesting that Ask_Ect is a specialized enzyme for this osmoadaptive biosynthetic pathway. However, none of these Ask_Ect enzymes have been functionally characterized. Pseudomonas stutzeri A1501 synthesizes both ectoine and hydroxyectoine in response to increased salinity, and it possesses two Ask enzymes: Ask_Lys and Ask_Ect. We purified both Ask enzymes and found significant differences with regard to their allosteric control: Ask_LysC was inhibited by threonine and in a concerted fashion by threonine and lysine, whereas Ask_Ect showed inhibition only by threonine. The ectABCD_askgenes from P. stutzeri A1501 were cloned and functionally expressed in Escherichia coli, and this led to osmostress protection. An E. colistrain carrying the plasmid-based ectABCD_askgene cluster produced significantly more ectoine/hydroxyectoine than a strain expressing the ectABCDgene cluster alone. This finding suggests a specialized role for Ask_Ect in ectoine/hydroxyectoine biosynthesis.
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Singh AK, Ulanov AV, Li Z, Jayaswal RK, Wilkinson BJ. Metabolomes of the psychrotolerant bacterium Listeria monocytogenes 10403S grown at 37 °C and 8 °C. Int J Food Microbiol 2011; 148:107-14. [PMID: 21645939 DOI: 10.1016/j.ijfoodmicro.2011.05.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 04/01/2011] [Accepted: 05/10/2011] [Indexed: 11/19/2022]
Abstract
Listeria monocytogenes is a food-borne pathogen with the ability to grow at refrigeration temperatures. Knowledge of the mechanisms involved in low temperature growth is incomplete and here we report the results of a metabolomics investigation of this. The small molecule contents of L. monocytogenes 10403S grown at 37 °C and 8 °C were compared by gas chromatography/mass spectrometry (GC/MS). Over 500 peaks were detected in both 37 °C and 8 °C-grown cells, and 103 were identified. Of the identified metabolites, the concentrations of 56 metabolites were increased (P<0.05), while the concentrations of 8 metabolites were decreased at low temperature. Metabolites increasing in concentration at 8 °C included amino acids, sugars, organic acids, urea cycle intermediates, polyamines, and different compatible solutes. A principal component analysis (PCA) was used to visualize and compare the matrix containing the data in 6 samples, and this clearly identified the 37 °C and 8 °C metabolomes as different. The results indicated that an increase in solute concentrations in the cytoplasm was associated with low temperature adaptation, which may be a response to chill stress with the effect of lowering the freezing point of intracellular water and decreasing ice crystal formation.
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Affiliation(s)
- Atul K Singh
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, Illinois 61790-4120, USA
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Michel E, Stephan R, Tasara T. The lmo0501 gene coding for a putative transcription activator protein in Listeria monocytogenes promotes growth under cold, osmotic and acid stress conditions. Food Microbiol 2011; 28:1261-5. [PMID: 21839374 DOI: 10.1016/j.fm.2011.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 03/16/2011] [Accepted: 05/06/2011] [Indexed: 10/18/2022]
Abstract
In Listeria monocytogenes EGDe, the lmo0501 gene locus encodes a protein similar to the mannitol transcription regulator (MltR) protein in Bacillus subtilis and Bacillus stearothermophilus. In this study we investigated its functional role in L. monocytogenes EGDe cells in view of growth under different stress conditions. Increased lmo0501 gene expression at mRNA level was detected in response to cold, osmotic and organic acid stress exposure. An EGDe Δlmo0501 mutant strain was diminished in growth compared to the wild type strain in minimal defined medium containing either glucose or fructose, as carbon sources. Growth of the lmo0501 null mutant was retarded growth under cold (4 °C), salt (NaCl) and organic acid stress conditions relative to the parental wild type strain. Our results confirm the role of the lmo0501 gene in adaptation of L. monocytogenes cells to food preservation stress conditions as well as to the efficient utilization of glucose and fructose as carbon sources.
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Affiliation(s)
- Evelyne Michel
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstr. 272, CH-8057 Zurich, Switzerland
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Soni KA, Nannapaneni R, Tasara T. The contribution of transcriptomic and proteomic analysis in elucidating stress adaptation responses of Listeria monocytogenes. Foodborne Pathog Dis 2011; 8:843-52. [PMID: 21495855 DOI: 10.1089/fpd.2010.0746] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The foodborne transmission of Listeria monocytogenes requires physiological adaptation to various conditions, including the cold, osmotic, heat, acid, alkaline, and oxidative stresses, associated with food hygiene, processing, and preservation measures. We review the current knowledge on the molecular stress adaptation responses in L. monocytogenes cells as revealed through transcriptome, proteome, genetic, and physiological analysis. The adaptation of L. monocytogenes to stress exposure is achieved through global expression changes in a large number of cellular components. In addition, the cross-protection of L. monocytogenes exposed to different stress environments might be conferred through various cellular machineries that seem to be commonly activated by the different stresses. To assist in designing L. monocytogenes mitigation strategies for ready-to-eat food products, further experiments are warranted to specifically evaluate the effects of food composition, additives, preservatives, and processing technologies on the modulation of L. monocytogenes cellular components in response to specific stresses.
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Affiliation(s)
- Kamlesh A Soni
- Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, Mississippi 39762, USA
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50
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Protection of Bacillus subtilis against cold stress via compatible-solute acquisition. J Bacteriol 2011; 193:1552-62. [PMID: 21296969 DOI: 10.1128/jb.01319-10] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Accumulation of compatible solutes is a strategy widely employed by bacteria to achieve cellular protection against high osmolarity. These compounds are also used in some microorganisms as thermostress protectants. We found that Bacillus subtilis uses the compatible solute glycine betaine as an effective cold stress protectant. Glycine betaine strongly stimulated growth at 15°C and permitted cell proliferation at the growth-inhibiting temperature of 13°C. Initial uptake of glycine betaine at 15°C was low but led eventually to the buildup of an intracellular pool whose size was double that found in cells grown at 35°C. Each of the three glycine betaine transporters (OpuA, OpuC, and OpuD) contributed to glycine betaine accumulation in the cold. Protection against cold stress was also accomplished when glycine betaine was synthesized from its precursor choline. Growth of a mutant defective in the osmoadaptive biosynthesis for the compatible solute proline was not impaired at low temperature (15°C). In addition to glycine betaine, the compatible solutes and osmoprotectants l-carnitine, crotonobetaine, butyrobetaine, homobetaine, dimethylsulfonioactetate, and proline betaine all served as cold stress protectants as well and were accumulated via known Opu transport systems. In contrast, the compatible solutes and osmoprotectants choline-O-sulfate, ectoine, proline, and glutamate were not cold protective. Our data highlight an underappreciated facet of the acclimatization of B. subtilis to cold environments and allow a comparison of the characteristics of compatible solutes with respect to their osmotic, heat, and cold stress-protective properties for B. subtilis cells.
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