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Unrath N, McCabe E, Macori G, Fanning S. Application of Whole Genome Sequencing to Aid in Deciphering the Persistence Potential of Listeria monocytogenes in Food Production Environments. Microorganisms 2021; 9:1856. [PMID: 34576750 PMCID: PMC8464834 DOI: 10.3390/microorganisms9091856] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/26/2023] Open
Abstract
Listeria monocytogenes is the etiological agent of listeriosis, a foodborne illness associated with high hospitalizations and mortality rates. This bacterium can persist in food associated environments for years with isolates being increasingly linked to outbreaks. This review presents a discussion of genomes of Listeria monocytogenes which are commonly regarded as persisters within food production environments, as well as genes which are involved in mechanisms aiding this phenotype. Although criteria for the detection of persistence remain undefined, the advent of whole genome sequencing (WGS) and the development of bioinformatic tools have revolutionized the ability to find closely related strains. These advancements will facilitate the identification of mechanisms responsible for persistence among indistinguishable genomes. In turn, this will lead to improved assessments of the importance of biofilm formation, adaptation to stressful conditions and tolerance to sterilizers in relation to the persistence of this bacterium, all of which have been previously associated with this phenotype. Despite much research being published around the topic of persistence, more insights are required to further elucidate the nature of true persistence and its implications for public health.
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Affiliation(s)
- Natalia Unrath
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
| | - Evonne McCabe
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
- Department of Microbiology, St. Vincent’s University Hospital, D04 T6F4 Dublin, Ireland
| | - Guerrino Macori
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
| | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
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2
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Yang Y, Yang Y, Fan Q, Huang Z, Li J, Wu Q, Tang X, Ding J, Han N, Xu B. Molecular and Biochemical Characterization of Salt-Tolerant Trehalose-6-Phosphate Hydrolases Identified by Screening and Sequencing Salt-Tolerant Clones From the Metagenomic Library of the Gastrointestinal Tract. Front Microbiol 2020; 11:1466. [PMID: 32733411 PMCID: PMC7358406 DOI: 10.3389/fmicb.2020.01466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 06/04/2020] [Indexed: 11/13/2022] Open
Abstract
The exploration and utilization of microbial salt-tolerant enzymatic and genetic resources are of great significance in the field of biotechnology and for the research of the adaptation of microorganisms to extreme environments. The presence of new salt-tolerant genes and enzymes in the microbial metagenomic library of the gastrointestinal tract has been confirmed through metagenomic technology. This paper aimed to identify and characterize enzymes that confer salt tolerance in the gastrointestinal tract microbe. By screening the fecal metagenomic library, 48 salt-tolerant clones were detected, of which 10 salt-tolerant clones exhibited stronger tolerance to 7% (wt/vol) NaCl and stability in different concentrations of NaCl [5%-9% (wt/vol)]. High-throughput sequencing and biological information analysis showed that 91 potential genes encoded proteins and enzymes that were widely involved in salt tolerance. Furthermore, two trehalose-6-phosphate hydrolase genes, namely, tre_P2 and tre_P3, were successfully cloned and expressed in Escherichia coli BL21 (DE3). By virtue of the substrate of p-nitrophenyl-α-D-glucopyranoside (pNPG) which can be specifically hydrolyzed by trehalose-6-phosphate hydrolase to produce glucose and p-nitrophenol, the two enzymes can act optimally at pH 7.5 and 30°C. Steady-state kinetics with pNPG showed that the K M and K cat values were 15.63 mM and 10.04 s-1 for rTRE_P2 and 12.51 mM and 10.71 s-1 for rTRE_P3, respectively. Characterization of enzymatic properties demonstrated that rTRE_P2 and rTRE_P3 were salt-tolerant. The enzymatic activity increased with increasing NaCl concentration, and the maximum activities of rTRE_P2 and rTRE_P3 were obtained at 4 and 3 M NaCl, respectively. The activities of rTRE_P2 increased by approximately 43-fold even after 24 h of incubation with 5 M NaCl. This study is the first to report the identification as well as molecular and biochemical characterization of salt-tolerant trehalose-6-phosphate hydrolase from the metagenomic library of the gastrointestinal tract. Results indicate the existence of numerous salt-tolerant genes and enzymes in gastrointestinal microbes and provide new insights into the salt-tolerant mechanisms in the gastrointestinal environment.
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Affiliation(s)
- Yanxia Yang
- School of Life Sciences, Yunnan Normal University, Kunming, China
| | - Yunjuan Yang
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Qin Fan
- School of Life Sciences, Yunnan Normal University, Kunming, China
| | - Zunxi Huang
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Junjun Li
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Qian Wu
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Xianghua Tang
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Junmei Ding
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Nanyu Han
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
| | - Bo Xu
- School of Life Sciences, Yunnan Normal University, Kunming, China.,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, China.,Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, China
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3
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Functional metagenomics identifies novel genes ABCTPP, TMSRP1 and TLSRP1 among human gut enterotypes. Sci Rep 2018; 8:1397. [PMID: 29362424 PMCID: PMC5780487 DOI: 10.1038/s41598-018-19862-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 01/09/2018] [Indexed: 01/08/2023] Open
Abstract
Every niche in the biosphere is touched by the seemingly endless capacity of microbes to transform the world around them by adapting swiftly and flexibly to the environmental changes, likewise the gastrointestinal tract is no exception. The ability to cope with rapid changes in external osmolarity is an important aspect of gut microbes for their survival and colonization. Identification of these survival mechanisms is a pivotal step towards understanding genomic suitability of a symbiont for successful human gut colonization. Here we highlight our recent work applying functional metagenomics to study human gut microbiome to identify candidate genes responsible for the salt stress tolerance. A plasmid borne metagenomic library of Bacteroidetes enriched human fecal metagenomic DNA led to identification of unique salt osmotolerance clones SR6 and SR7. Subsequent gene analysis combined with functional studies revealed that TLSRP1 within pSR7 and TMSRP1 and ABCTPP of pSR6 are the active loci responsible for osmotolerance through an energy dependent mechanism. Our study elucidates the novel genetic machinery involved in bestowing osmotolerance in Prevotella and Bacteroidetes, the predominant microbial groups in a North Indian population. This study unravels an alternative method for imparting ionic stress tolerance, which may be prevalent in the human gut microbiome.
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Hoffmann T, Bleisteiner M, Sappa PK, Steil L, Mäder U, Völker U, Bremer E. Synthesis of the compatible solute proline by Bacillus subtilis: point mutations rendering the osmotically controlled proHJ promoter hyperactive. Environ Microbiol 2017; 19:3700-3720. [PMID: 28752945 DOI: 10.1111/1462-2920.13870] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/09/2017] [Accepted: 07/24/2017] [Indexed: 01/29/2023]
Abstract
The ProJ and ProH enzymes of Bacillus subtilis catalyse together with ProA (ProJ-ProA-ProH), osmostress-adaptive synthesis of the compatible solute proline. The proA-encoded gamma-glutamyl phosphate reductase is also used for anabolic proline synthesis (ProB-ProA-ProI). Transcription of the proHJ operon is osmotically inducible whereas that of the proBA operon is not. Targeted and quantitative proteome analysis revealed that the amount of ProA is not limiting for the interconnected anabolic and osmostress-responsive proline production routes. A key player for enhanced osmostress-adaptive proline production is the osmotically regulated proHJ promoter. We used site-directed mutagenesis to study the salient features of this stress-responsive promoter. Two important features were identified: (i) deviations of the proHJ promoter from the consensus sequence of SigA-type promoters serve to keep transcription low under non-inducing growth conditions, while still allowing a finely tuned induction of transcriptional activity when the external osmolarity is increased and (ii) a suboptimal spacer length for SigA-type promoters of either 16-bp (the natural proHJ promoter), or 18-bp (a synthetic promoter variant) is strictly required to allow regulation of promoter activity in proportion to the external salinity. Collectively, our data suggest that changes in the local DNA structure at the proHJ promoter are important determinants for osmostress-inducibility of transcription.
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Affiliation(s)
- Tamara Hoffmann
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, Marburg D-35043, Germany
| | - Monika Bleisteiner
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, Marburg D-35043, Germany
| | - Praveen Kumar Sappa
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Leif Steil
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Ulrike Mäder
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Uwe Völker
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15, Greifswald D-17475, Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, Marburg D-35043, Germany
- LOEWE-Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerweinstr. 6, Marburg D-35043, Germany
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5
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Hingston P, Chen J, Dhillon BK, Laing C, Bertelli C, Gannon V, Tasara T, Allen K, Brinkman FSL, Truelstrup Hansen L, Wang S. Genotypes Associated with Listeria monocytogenes Isolates Displaying Impaired or Enhanced Tolerances to Cold, Salt, Acid, or Desiccation Stress. Front Microbiol 2017; 8:369. [PMID: 28337186 PMCID: PMC5340757 DOI: 10.3389/fmicb.2017.00369] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/22/2017] [Indexed: 01/11/2023] Open
Abstract
The human pathogen Listeria monocytogenes is a large concern in the food industry where its continuous detection in food products has caused a string of recalls in North America and Europe. Most recognized for its ability to grow in foods during refrigerated storage, L. monocytogenes can also tolerate several other food-related stresses with some strains possessing higher levels of tolerances than others. The objective of this study was to use a combination of phenotypic analyses and whole genome sequencing to elucidate potential relationships between L. monocytogenes genotypes and food-related stress tolerance phenotypes. To accomplish this, 166 L. monocytogenes isolates were sequenced and evaluated for their ability to grow in cold (4°C), salt (6% NaCl, 25°C), and acid (pH 5, 25°C) stress conditions as well as survive desiccation (33% RH, 20°C). The results revealed that the stress tolerance of L. monocytogenes is associated with serotype, clonal complex (CC), full length inlA profiles, and the presence of a plasmid which was identified in 55% of isolates. Isolates with full length inlA exhibited significantly (p < 0.001) enhanced cold tolerance relative to those harboring a premature stop codon (PMSC) in this gene. Similarly, isolates possessing a plasmid demonstrated significantly (p = 0.013) enhanced acid tolerance. We also identified nine new L. monocytogenes sequence types, a new inlA PMSC, and several connections between CCs and the presence/absence or variations of specific genetic elements. A whole genome single-nucleotide-variants phylogeny revealed sporadic distribution of tolerant isolates and closely related sensitive and tolerant isolates, highlighting that minor genetic differences can influence the stress tolerance of L. monocytogenes. Specifically, a number of cold and desiccation sensitive isolates contained PMSCs in σB regulator genes (rsbS, rsbU, rsbV). Collectively, the results suggest that knowing the sequence type of an isolate in addition to screening for the presence of full-length inlA and a plasmid, could help food processors and food agency investigators determine why certain isolates might be persisting in a food processing environment. Additionally, increased sequencing of L. monocytogenes isolates in combination with stress tolerance profiling, will enhance the ability to identify genetic elements associated with higher risk strains.
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Affiliation(s)
- Patricia Hingston
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| | - Jessica Chen
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| | - Bhavjinder K. Dhillon
- Department of Molecular Biology and Biochemistry, Simon Fraser UniversityBurnaby, BC, Canada
| | - Chad Laing
- Laboratory for Foodborne Zoonoses, Public Health Agency of CanadaLethbridge, AB, Canada
| | - Claire Bertelli
- Department of Molecular Biology and Biochemistry, Simon Fraser UniversityBurnaby, BC, Canada
| | - Victor Gannon
- Laboratory for Foodborne Zoonoses, Public Health Agency of CanadaLethbridge, AB, Canada
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, University of ZurichZurich, Switzerland
| | - Kevin Allen
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| | - Fiona S. L. Brinkman
- Department of Molecular Biology and Biochemistry, Simon Fraser UniversityBurnaby, BC, Canada
| | - Lisbeth Truelstrup Hansen
- Division for Microbiology and Production, National Food Institute, Technical University of DenmarkKongens Lyngby, Denmark
| | - Siyun Wang
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
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6
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Ma Y, Wang Q, Gao X, Zhang Y. Biosynthesis and uptake of glycine betaine as cold-stress response to low temperature in fish pathogen Vibrio anguillarum. J Microbiol 2016; 55:44-55. [PMID: 28035596 DOI: 10.1007/s12275-017-6370-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/06/2016] [Accepted: 10/07/2016] [Indexed: 12/28/2022]
Abstract
Fish pathogen Vibrio anguillarum, a mesophile bacterium, is usually found in estuarine and marine coastal ecosystems worldwide that pose a constant stress to local organism by its fluctuation in salinity as well as notable temperature change. Though V. anguillarum is able to proliferate while maintain its pathogenicity under low temperature (5-18°C), so far, coldadaption molecular mechanism of the bacteria is unknown. In this study, V. anguillarum was found possessing a putative glycine betaine synthesis system, which is encoded by betABI and synthesizes glycine betaine from its precursor choline. Furthermore, significant up-regulation of the bet gene at the transcriptional level was noted in log phase in response to cold-stress. Moreover, the accumulation of betaine glycine was only found appearing at low growth temperatures, suggesting that response regulation of both synthesis system and transporter system are cold-dependent. Furthermore, in-frame deletion mutation in the two putative ABC transporters and three putative BCCT family transporters associated with glycine betaine uptake could not block cellular accumulation of betaine glycine in V. anguillarum under coldstress, suggesting the redundant feature in V. anguillarum betaine transporter system. These findings confirmed that glycine betaine serves as an effective cold stress protectant and highlighted an underappreciated facet of the acclimatization of V. anguillarum to cold environments.
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Affiliation(s)
- Yue Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, P. R. China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, P. R. China
- Shanghai Collaborative Innovation Center for Biomanufacturing, Shanghai, 200237, P. R. China
| | - Xiating Gao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, P. R. China.
- Shanghai Collaborative Innovation Center for Biomanufacturing, Shanghai, 200237, P. R. China.
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7
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Keane SM, Culligan EP, Hoffmann RF, Gahan CGM, Hill C, Snelling WJ, Sleator RD. Shedding light on betL*: pPL2-lux mediated real-time analysis of betL* expression in Listeria monocytogenes. Bioengineered 2016; 7:116-9. [PMID: 27212260 DOI: 10.1080/21655979.2016.1171438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
We propose a mechanism of action for the betL* mutation which is based on DNA topology. Removing a single thymine residue from the betL σ(A) promoter's -10 and -35 spacer results in a 'twist'-mediated activation of transcription which accounts for the osmotolerance phenotype observed for strains expressing betL*.
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Affiliation(s)
- Shauna M Keane
- a Department of Biological Sciences , Cork Institute of Technology , Rossa Avenue, Bishopstown, Cork , Ireland
| | - Eamonn P Culligan
- a Department of Biological Sciences , Cork Institute of Technology , Rossa Avenue, Bishopstown, Cork , Ireland
| | - Roland F Hoffmann
- b APC Microbiome Institute, University College Cork , College Road, Cork , Ireland
| | - Cormac G M Gahan
- b APC Microbiome Institute, University College Cork , College Road, Cork , Ireland.,c School of Microbiology, University College Cork , College Road, Cork , Ireland.,d School of Pharmacy, University College Cork , College Road, Cork , Ireland
| | - Colin Hill
- b APC Microbiome Institute, University College Cork , College Road, Cork , Ireland.,c School of Microbiology, University College Cork , College Road, Cork , Ireland
| | - William J Snelling
- e Biomedical Sciences Research Institute, Ulster University , Northern Ireland
| | - Roy D Sleator
- a Department of Biological Sciences , Cork Institute of Technology , Rossa Avenue, Bishopstown, Cork , Ireland.,b APC Microbiome Institute, University College Cork , College Road, Cork , Ireland
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8
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Abstract
The review centers on the human gastrointestinal tract; focusing first on the bacterial stress responses needed to overcome the physiochemical defenses of the host, specifically how these stress survival strategies can be used as targets for alternative infection control strategies. The concluding section focuses on recent developments in molecular diagnostics; centring on the shifting paradigm from culture to molecular based diagnostics.
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Affiliation(s)
- Roy D Sleator
- a Department of Biological Sciences ; Cork Institute of Technology ; Bishopstown , Cork , Ireland
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9
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Sleator RD. Designer probiotics: Development and applications in gastrointestinal health. World J Gastrointest Pathophysiol 2015; 6:73-78. [PMID: 26301121 PMCID: PMC4540709 DOI: 10.4291/wjgp.v6.i3.73] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/23/2015] [Accepted: 07/14/2015] [Indexed: 02/06/2023] Open
Abstract
Given the increasing commercial and clinical relevance of probiotics, improving their stress tolerance profile and ability to overcome the physiochemical defences of the host is an important biological goal. Herein, I review the current state of the art in the design of engineered probiotic cultures, with a specific focus on their utility as therapeutics for the developing world; from the treatment of chronic and acute enteric infections, and their associated diarrhoeal complexes, to targeting HIV and application as novel mucosal vaccine delivery vehicles.
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10
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Feeney A, Kropp KA, O’Connor R, Sleator RD. Cronobacter sakazakii: stress survival and virulence potential in an opportunistic foodborne pathogen. Gut Microbes 2015; 5:711-8. [PMID: 25562731 PMCID: PMC4615781 DOI: 10.4161/19490976.2014.983774] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A characteristic feature of the opportunistic foodborne pathogen Cronobacter sakazakii is its ability to survive in extremely arid environments, such as powdered infant formula, making it a dangerous opportunistic pathogen of individuals of all age groups, especially infants and neonates. Herein, we provide a brief overview of the pathogen; clinical manifestations, environmental reservoirs and our current understanding of stress response mechanisms and virulence factors which allow it to cause disease.
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Affiliation(s)
- Audrey Feeney
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Kai A Kropp
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Roxana O’Connor
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Roy D Sleator
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland,Correspondence to: Roy D Sleator;
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11
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Culligan EP, Sleator RD, Marchesi JR, Hill C. Metagenomic identification of a novel salt tolerance gene from the human gut microbiome which encodes a membrane protein with homology to a brp/blh-family β-carotene 15,15'-monooxygenase. PLoS One 2014; 9:e103318. [PMID: 25058308 PMCID: PMC4110020 DOI: 10.1371/journal.pone.0103318] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/29/2014] [Indexed: 12/30/2022] Open
Abstract
The human gut microbiome consists of at least 3 million non-redundant genes, 150 times that of the core human genome. Herein, we report the identification and characterisation of a novel stress tolerance gene from the human gut metagenome. The locus, assigned brpA, encodes a membrane protein with homology to a brp/blh-family β-carotene monooxygenase. Cloning and heterologous expression of brpA in Escherichia coli confers a significant salt tolerance phenotype. Furthermore, when cultured in the presence of exogenous β-carotene, cell pellets adopt a red/orange pigmentation indicating the incorporation of carotenoids in the cell membrane.
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Affiliation(s)
- Eamonn P. Culligan
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- School of Microbiology, 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
- * E-mail: (CH); (RDS); (JRM)
| | - Julian R. Marchesi
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
- Department of Hepatology and Gastroenterology, Imperial College London, London, United Kingdom
- * E-mail: (CH); (RDS); (JRM)
| | - Colin Hill
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
- * E-mail: (CH); (RDS); (JRM)
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12
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Culligan EP, Marchesi JR, Hill C, Sleator RD. Combined metagenomic and phenomic approaches identify a novel salt tolerance gene from the human gut microbiome. Front Microbiol 2014; 5:189. [PMID: 24808895 PMCID: PMC4010731 DOI: 10.3389/fmicb.2014.00189] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 04/07/2014] [Indexed: 12/13/2022] Open
Abstract
In the current study, a number of salt-tolerant clones previously isolated from a human gut metagenomic library were screened using Phenotype MicroArray (PM) technology to assess their functional capacity. PM's can be used to study gene function, pathogenicity, metabolic capacity and identify drug targets using a series of specialized microtitre plate assays, where each well of the microtitre plate contains a different set of conditions and tests a different phenotype. Cellular respiration is monitored colorimetrically by the reduction of a tetrazolium dye. One clone, SMG 9, was found to be positive for utilization/transport of L-carnitine (a well-characterized osmoprotectant) in the presence of 6% w/v sodium chloride (NaCl). Subsequent experiments revealed a significant growth advantage in minimal media containing NaCl and L-carnitine. Fosmid sequencing revealed putative candidate genes responsible for the phenotype. Subsequent cloning of two genes did not replicate the L-carnitine-associated phenotype, although one of the genes, a σ54-dependent transcriptional regulator, did confer salt tolerance to Escherichia coli when expressed in isolation. The original clone, SMG 9, was subsequently found to have lost the original observed phenotype upon further investigation. Nevertheless, this study demonstrates the usefulness of a phenomic approach to assign a functional role to metagenome-derived clones.
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Affiliation(s)
- Eamonn P Culligan
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork Cork, Ireland ; School of Microbiology, University College Cork Cork, Ireland
| | - Julian R Marchesi
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork Cork, Ireland ; Cardiff School of Biosciences, Cardiff University Cardiff, UK ; Department of Surgery and Cancer, Centre for Digestive and Gut Health, Imperial College London London, UK
| | - Colin Hill
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork Cork, Ireland ; School of Microbiology, University College Cork Cork, Ireland
| | - Roy D Sleator
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork Cork, Ireland ; Department of Biological Sciences, Cork Institute of Technology Cork, Ireland
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Culligan EP, Sleator RD, Marchesi JR, Hill C. Metagenomics and novel gene discovery: promise and potential for novel therapeutics. Virulence 2014; 5:399-412. [PMID: 24317337 PMCID: PMC3979868 DOI: 10.4161/viru.27208] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/21/2013] [Accepted: 11/14/2013] [Indexed: 02/06/2023] Open
Abstract
Metagenomics provides a means of assessing the total genetic pool of all the microbes in a particular environment, in a culture-independent manner. It has revealed unprecedented diversity in microbial community composition, which is further reflected in the encoded functional diversity of the genomes, a large proportion of which consists of novel genes. Herein, we review both sequence-based and functional metagenomic methods to uncover novel genes and outline some of the associated problems of each type of approach, as well as potential solutions. Furthermore, we discuss the potential for metagenomic biotherapeutic discovery, with a particular focus on the human gut microbiome and finally, we outline how the discovery of novel genes may be used to create bioengineered probiotics.
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Affiliation(s)
- Eamonn P Culligan
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- School of Microbiology; University College Cork; Cork, Ireland
| | - Roy D Sleator
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Julian R Marchesi
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- Cardiff School of Biosciences; Cardiff University; Cardiff, UK
- Department of Hepatology and Gastroenterology; Imperial College London; London, UK
| | - Colin Hill
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- School of Microbiology; University College Cork; Cork, Ireland
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Zaprasis A, Hoffmann T, Wünsche G, Flórez LA, Stülke J, Bremer E. Mutational activation of the RocR activator and of a crypticrocDEFpromoter bypass loss of the initial steps of proline biosynthesis inBacillus subtilis. Environ Microbiol 2013; 16:701-17. [DOI: 10.1111/1462-2920.12193] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/07/2013] [Accepted: 06/11/2013] [Indexed: 12/11/2022]
Affiliation(s)
- Adrienne Zaprasis
- Department of Biology, Laboratory for Microbiology; Philipps-University Marburg; Karl-von-Frisch Str. 8 Marburg D-35032 Germany
| | - Tamara Hoffmann
- Department of Biology, Laboratory for Microbiology; Philipps-University Marburg; Karl-von-Frisch Str. 8 Marburg D-35032 Germany
| | - Guido Wünsche
- Department of Biology, Laboratory for Microbiology; Philipps-University Marburg; Karl-von-Frisch Str. 8 Marburg D-35032 Germany
| | - Lope A. Flórez
- Department of General Microbiology; Institute of Microbiology and Genetics; Georg-August University Göttingen; Grisebachstr. 8 Göttingen D-37077 Germany
| | - Jörg Stülke
- Department of General Microbiology; Institute of Microbiology and Genetics; Georg-August University Göttingen; Grisebachstr. 8 Göttingen D-37077 Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology; Philipps-University Marburg; Karl-von-Frisch Str. 8 Marburg D-35032 Germany
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