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Thobor BM, Tilstra A, Mueller B, Haas A, Hehemann JH, Wild C. Mucus carbohydrate composition correlates with scleractinian coral phylogeny. Sci Rep 2024; 14:14019. [PMID: 38890484 PMCID: PMC11189453 DOI: 10.1038/s41598-024-64828-5] [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: 12/18/2023] [Accepted: 06/13/2024] [Indexed: 06/20/2024] Open
Abstract
The mucus surface layer serves vital functions for scleractinian corals and consists mainly of carbohydrates. Its carbohydrate composition has been suggested to be influenced by environmental conditions (e.g., temperature, nutrients) and microbial pressures (e.g., microbial degradation, microbial coral symbionts), yet to what extend the coral mucus composition is determined by phylogeny remains to be tested. To investigate the variation of mucus carbohydrate compositions among coral species, we analyzed the composition of mucosal carbohydrate building blocks (i.e., monosaccharides) for five species of scleractinian corals, supplemented with previously reported data, to discern overall patterns using cluster analysis. Monosaccharide composition from a total of 23 species (belonging to 14 genera and 11 families) revealed significant differences between two phylogenetic clades that diverged early in the evolutionary history of scleractinian corals (i.e., complex and robust; p = 0.001, R2 = 0.20), mainly driven by the absence of arabinose in the robust clade. Despite considerable differences in environmental conditions and sample analysis protocols applied, coral phylogeny significantly correlated with monosaccharide composition (Mantel test: p < 0.001, R2 = 0.70). These results suggest that coral mucus carbohydrates display phylogenetic dependence and support their essential role in the functioning of corals.
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Affiliation(s)
- Bianca M Thobor
- Department of Marine Ecology, University of Bremen, Bremen, Germany.
| | - Arjen Tilstra
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Benjamin Mueller
- Department of Marine Ecology, University of Bremen, Bremen, Germany
- Department of Freshwater and Marine Ecology, University of Amsterdam, Amsterdam, The Netherlands
- CARMABI Foundation, Willemstad, Curaçao
| | - Andreas Haas
- Department of Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Texel, The Netherlands
| | - Jan-Hendrik Hehemann
- Department of Marine Glycobiology, Max Planck Institute for Marine Microbiology, Bremen, Germany
- MARUM Centre for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Christian Wild
- Department of Marine Ecology, University of Bremen, Bremen, Germany
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2
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Stege PB, Hordijk J, Sandholt AKS, Zomer AL, Viveen MC, Rogers MRC, Salomons M, Wagenaar JA, Mughini-Gras L, Willems RJL, Paganelli FL. Gut Colonization by ESBL-Producing Escherichia coli in Dogs Is Associated with a Distinct Microbiome and Resistome Composition. Microbiol Spectr 2023; 11:e0006323. [PMID: 37404183 PMCID: PMC10434115 DOI: 10.1128/spectrum.00063-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/12/2023] [Indexed: 07/06/2023] Open
Abstract
The gut microbiome of humans and animals acts as a reservoir of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC). Dogs are known for having a high prevalence of ESBL-EC in their gut microbiota, although their ESBL-EC carrier status often shifts over time. We hypothesized that the gut microbiome composition of dogs is implicated in ESBL-EC colonization status. Therefore, we assessed whether ESBL-EC carriage in dogs is associated with changes in the gut microbiome and resistome. Fecal samples were collected longitudinally from 57 companion dogs in the Netherlands every 2 weeks for a total of 6 weeks (n = 4 samples/dog). Carriage of ESBL-EC was determined through selective culturing and PCR and in line with previous studies, we observed a high prevalence of ESBL-EC carriage in dogs. Using 16s rRNA gene profiling we found significant associations between detected ESBL-EC carriage and an increased abundance of Clostridium sensu stricto 1, Enterococcus, Lactococcus, and the shared genera of Escherichia-Shigella in the dog microbiome. A resistome capture sequencing approach (ResCap) furthermore, revealed associations between detected ESBL-EC carriage and the increased abundance of the antimicrobial resistance genes: cmlA, dfrA, dhfR, floR, and sul3. In summary, our study showed that ESBL-EC carriage is associated with a distinct microbiome and resistome composition. IMPORTANCE The gut microbiome of humans and animals is an important source of multidrug resistant pathogens, including beta-lactamase-producing Escherichia coli (ESBL-EC). In this study, we assessed if the carriage of ESBL-EC in dogs was associated with changes in gut composition of bacteria and antimicrobial resistant genes (ARGs). Therefore, stool samples from 57 dogs were collected every 2 weeks for a total of 6 weeks. Sixty eight percent of the dogs carried ESBL-EC during at least one of the time points analyzed. By investigating the gut microbiome and resistome composition, we observed specific changes at time points when dogs were colonized with ESBL-EC compared to time points whenESBL-EC were not detected. In conclusion, our study highlights the importance to study the microbial diversity in companion animals, as gut colonization of particular antimicrobial resistant bacteria might be an indication of a changed microbial composition that is associated with the selection of particular ARGs.
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Affiliation(s)
- Paul B. Stege
- Department of Medical Microbiology, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Joost Hordijk
- Centre for Infectious Disease Control Netherlands, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Arnar K. S. Sandholt
- Utrecht University, Institute for Risk Assessment Sciences, Utrecht, The Netherlands
| | - Aldert L. Zomer
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- WHO Collaborating Centre for Reference and Research on Campylobacter and Antimicrobial Resistance from an One Health Perspective/OIE Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands
| | - Marco C. Viveen
- Department of Medical Microbiology, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Malbert R. C. Rogers
- Department of Medical Microbiology, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Moniek Salomons
- Department of Medical Microbiology, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Jaap A. Wagenaar
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- WHO Collaborating Centre for Reference and Research on Campylobacter and Antimicrobial Resistance from an One Health Perspective/OIE Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands
| | - Lapo Mughini-Gras
- Centre for Infectious Disease Control Netherlands, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
- Utrecht University, Institute for Risk Assessment Sciences, Utrecht, The Netherlands
| | - Rob J. L. Willems
- Department of Medical Microbiology, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Fernanda L. Paganelli
- Department of Medical Microbiology, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
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3
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Loughran RM, Emsley SA, Jefferson T, Wasson BJ, Deadmond MC, Knauss TL, Pfannmuller KM, Lippert KJ, Miller G, Cline LC, Oline DK, Koyack MJ, Grant-Beurmann S, Gaylor MO, Saw JH, Ushijima B, Videau P. Vibrio tetraodonis subsp. pristinus subsp. nov., isolated from the coral Acropora cytherea at Palmyra Atoll, and creation and emended description of Vibrio tetraodonis subsp. tetraodonis subsp. nov. Antonie Van Leeuwenhoek 2022; 115:1215-1228. [PMID: 35920985 DOI: 10.1007/s10482-022-01766-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 07/10/2022] [Indexed: 11/30/2022]
Abstract
Strain OCN044T was isolated from the homogenised tissue and mucus of an apparently healthy Acropora cytherea coral fragment collected from the western reef terrace of Palmyra Atoll in the Northern Line Islands and was taxonomically evaluated with a polyphasic approach. The morphological and chemotaxonomic properties are consistent with characteristics of the genus Vibrio: Gram-stain-negative rods, oxidase- and catalase-positive, and motile by means of a polar flagellum. Strain OCN044T can be differentiated as a novel subspecies based on 21 differences among chemotaxonomic features (e.g., fatty acids percentages for C12:0 and C18:1 ω7c), enzymatic activities (e.g., DNase and cystine arylamidase), and carbon sources utilized (e.g., L-xylose and D-melezitose) from its nearest genetic relative. Phylogenetic analysis and genomic comparisons show close evolutionary relatedness to Vibrio tetraodonis A511T but the overall genomic relatedness indices identify strain OCN044T as a distinct subspecies. Based on a polyphasic characterisation, differences in genomic and taxonomic data, strain OCN044T represents a novel subspecies of V. tetraodonis A511T, for which the name Vibrio tetraodonis subsp. pristinus subsp. nov. is proposed. The type strain is OCN044T (= LMG 31895T = DSM 111778T).
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Affiliation(s)
- Rachel M Loughran
- Department of Biology, Southern Oregon University, Ashland, OR, USA.,Microbiology Graduate Program, University of Delaware, Newark, DE, USA
| | - Sarah A Emsley
- Department of Biology, Southern Oregon University, Ashland, OR, USA
| | - Tori Jefferson
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | | | | | - Taylor L Knauss
- Department of Biology, Southern Oregon University, Ashland, OR, USA
| | | | - Katherine J Lippert
- Department of Biology, Southern Oregon University, Ashland, OR, USA.,Triplebar, Emeryville, CA, USA
| | - Gregory Miller
- Natural Sciences Department, Flagler College, St. Augustine, FL, USA
| | | | - David K Oline
- Department of Biology, Southern Oregon University, Ashland, OR, USA
| | - Marc J Koyack
- Department of Chemistry, Southern Oregon University, Ashland, OR, USA
| | - Silvia Grant-Beurmann
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michael O Gaylor
- Department of Chemistry, Dakota State University, Madison, SD, USA
| | - Jimmy H Saw
- Department of Biological Sciences, The George Washington University, Washington, D.C, USA
| | - Blake Ushijima
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA.
| | - Patrick Videau
- Department of Biology, Southern Oregon University, Ashland, OR, USA. .,Bayer Crop Science, Chesterfield, MO, USA.
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4
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Ghaly TM, Gillings MR, Penesyan A, Qi Q, Rajabal V, Tetu SG. The Natural History of Integrons. Microorganisms 2021; 9:2212. [PMID: 34835338 PMCID: PMC8618304 DOI: 10.3390/microorganisms9112212] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 11/17/2022] Open
Abstract
Integrons were first identified because of their central role in assembling and disseminating antibiotic resistance genes in commensal and pathogenic bacteria. However, these clinically relevant integrons represent only a small proportion of integron diversity. Integrons are now known to be ancient genetic elements that are hotspots for genomic diversity, helping to generate adaptive phenotypes. This perspective examines the diversity, functions, and activities of integrons within both natural and clinical environments. We show how the fundamental properties of integrons exquisitely pre-adapted them to respond to the selection pressures imposed by the human use of antimicrobial compounds. We then follow the extraordinary increase in abundance of one class of integrons (class 1) that has resulted from its acquisition by multiple mobile genetic elements, and subsequent colonisation of diverse bacterial species, and a wide range of animal hosts. Consequently, this class of integrons has become a significant pollutant in its own right, to the extent that it can now be detected in most ecosystems. As human activities continue to drive environmental instability, integrons will likely continue to play key roles in bacterial adaptation in both natural and clinical settings. Understanding the ecological and evolutionary dynamics of integrons can help us predict and shape these outcomes that have direct relevance to human and ecosystem health.
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Affiliation(s)
- Timothy M. Ghaly
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; (T.M.G.); (A.P.); (Q.Q.); (V.R.)
| | - Michael R. Gillings
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; (T.M.G.); (A.P.); (Q.Q.); (V.R.)
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia;
| | - Anahit Penesyan
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; (T.M.G.); (A.P.); (Q.Q.); (V.R.)
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia;
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Qin Qi
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; (T.M.G.); (A.P.); (Q.Q.); (V.R.)
| | - Vaheesan Rajabal
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; (T.M.G.); (A.P.); (Q.Q.); (V.R.)
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia;
| | - Sasha G. Tetu
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia;
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
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5
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Takagi T, Yoshioka Y, Zayasu Y, Satoh N, Shinzato C. Transcriptome Analyses of Immune System Behaviors in Primary Polyp of Coral Acropora digitifera Exposed to the Bacterial Pathogen Vibrio coralliilyticus under Thermal Loading. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:748-759. [PMID: 32696240 DOI: 10.1007/s10126-020-09984-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Elevated sea surface temperature associated with global warming is a serious threat to coral reefs. Elevated temperatures directly or indirectly alter the distribution of coral-pathogen interactions and thereby exacerbate infectious coral diseases. The pathogenic bacterium Vibrio coralliilyticus is well-known as a causative agent of infectious coral disease. Rising sea surface temperature promotes the infection of corals by this bacterium, which causes several coral pathologies, such as bacterial bleaching, tissue lysis, and white syndrome. However, the effects of thermal stress on coral immune responses to the pathogen are poorly understood. To delineate the effects of thermal stress on coral immunity, we performed transcriptome analysis of aposymbiotic primary polyps of the reef-building coral Acropora digitifera exposed to V. coralliilyticus under thermal stress conditions. V. coralliilyticus infection of coral that was under thermal stress had negative effects on various molecular processes, including suppression of gene expression related to the innate immune response. In response to the pathogen, the coral mounted various responses including changes in protein metabolism, exosome release delivering signal molecules, extracellular matrix remodeling, and mitochondrial metabolism changes. Based on these results, we provide new insights into innate immunity of A. digitifera against pathogen infection under thermal stress conditions.
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Affiliation(s)
- Toshiyuki Takagi
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan.
| | - Yuki Yoshioka
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8564, Japan
| | - Yuna Zayasu
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Chuya Shinzato
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan
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6
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Ali N, Lin Y, Qing Z, Xiao D, Ud Din A, Ali I, Lian T, Chen B, Wen R. The Role of Agriculture in the Dissemination of Class 1 Integrons, Antimicrobial Resistance, and Diversity of Their Gene Cassettes in Southern China. Genes (Basel) 2020; 11:genes11091014. [PMID: 32872161 PMCID: PMC7564866 DOI: 10.3390/genes11091014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 12/15/2022] Open
Abstract
Integrons are hot spots for acquiring gene cassettes from the environment and play a major role in the bacterial evolution and dissemination of antimicrobial resistance (AMR), thus posing a serious threat. There are currently studies on integrons and antibiotic resistance genes; however, the presence and association of integrons in different agricultural crops and their subsequent dissemination and role in AMR have not been reported previously. This study examines the abundance of integrons, their gene cassette diversity in various crop soils, and their role in the dissemination of AMR in the southern region of China. Samples from different agri-crop soil, such as rice (R.S), sugarcane (S.S), citrus (C.S), banana (B.S), agricultural runoff (the point where the runoff of all sites meet (R.O)), and wild (non-agricultural) soil (W.S), were collected. Quantitative PCR was used to determine the abundance of integrons, and clone libraries were constructed to examine the gene cassette arrays. All the tested samples were found positive for Class-I (CL1) integrons and revealed a higher concentration and higher relative abundance of R.S than the others, with the least found at the W.S site. The W.S CL1 cassette arrays were found empty, and no putative conserved domains were found. The R.O was found to contain a high number of gene cassettes with various functions, while the smallest number of gene cassettes was found in the S.S among the crop soils. Most of the gene cassettes presented by the R.O were primarily shared with other sites, and the antibiotic-resistant genes were consistently observed to be dominant. The constructed clone libraries represented a diverse gene cassette array with 16% novel gene cassettes that play a vital role in pathogenesis, transportation, biosynthesis, and AMR. Most resistance-related gene cassettes were associated with the genes encoding resistance to quaternary ammonium compound (QAC) and aminoglycosides. This study highlights the significant differences in the abundance of integrons among various agricultural soils and offers deep insight into the pools of gene cassettes that play a key role in the dissemination of integrons and AMR.
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Affiliation(s)
- Niyaz Ali
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Yinfu Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Zhen Qing
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Dan Xiao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Ahmad Ud Din
- Drug Discovery Research Center, South West Medical University, Luzhou 646000, China;
| | - Izhar Ali
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Tengxiang Lian
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, South China Agricultural University, Guangzhou 510642, China;
| | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
- Guangxi Key Lab for Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Ronghui Wen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
- Correspondence: ; Tel.: +86-13669614062
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7
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The Peril and Promise of Integrons: Beyond Antibiotic Resistance. Trends Microbiol 2020; 28:455-464. [PMID: 31948729 DOI: 10.1016/j.tim.2019.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/13/2019] [Accepted: 12/09/2019] [Indexed: 12/11/2022]
Abstract
Integrons are bacterial genetic elements that can capture, rearrange, and express mobile gene cassettes. They are best known for their role in disseminating antibiotic-resistance genes among pathogens. Their ability to rapidly spread resistance phenotypes makes it important to consider what other integron-mediated traits might impact human health in the future, such as increased virulence, pathogenicity, or resistance to novel antimicrobial strategies. Exploring the functional diversity of cassettes and understanding their de novo creation will allow better pre-emptive management of bacterial growth, while also facilitating development of technologies that could harness integron activity. If we can control integrons and cassette formation, we could use integrons as a platform for enzyme discovery and to construct novel biochemical pathways, with applications in bioremediation or biosynthesis of industrial and therapeutic molecules. Integron activity thus holds both peril and promise for humans.
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8
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Vibrio coralliilyticus infection triggers a behavioural response and perturbs nutritional exchange and tissue integrity in a symbiotic coral. ISME JOURNAL 2018; 13:989-1003. [PMID: 30542077 PMCID: PMC6462045 DOI: 10.1038/s41396-018-0327-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 10/22/2018] [Accepted: 11/17/2018] [Indexed: 12/17/2022]
Abstract
Under homoeostatic conditions, the relationship between the coral Pocillopora damicornis and Vibrio coralliilyticus is commensal. An increase in temperature, or in the abundance of V. coralliilyticus, can turn this association pathogenic, causing tissue lysis, expulsion of the corals’ symbiotic algae (genus Symbiodinium), and eventually coral death. Using a combination of microfluidics, fluorescence microscopy, stable isotopes, electron microscopy and NanoSIMS isotopic imaging, we provide insights into the onset and progression of V. coralliilyticus infection in the daytime and at night, at the tissue and (sub-)cellular level. The objective of our study was to connect the macro-scale behavioural response of the coral to the micro-scale nutritional interactions that occur between the host and its symbiont. In the daytime, polyps enhanced their mucus production, and actively spewed pathogens. Vibrio infection primarily resulted in the formation of tissue lesions in the coenosarc. NanoSIMS analysis revealed infection reduced 13C-assimilation in Symbiodinium, but increased 13C-assimilation in the host. In the night incubations, no mucus spewing was observed, and a mucus film was formed on the coral surface. Vibrio inoculation and infection at night showed reduced 13C-turnover in Symbiodinium, but did not impact host 13C-turnover. Our results show that both the nutritional interactions that occur between the two symbiotic partners and the behavioural response of the host organism play key roles in determining the progression and severity of host-pathogen interactions. More generally, our approach provides a new means of studying interactions (ranging from behavioural to metabolic scales) between partners involved in complex holobiont systems, under both homoeostatic and pathogenic conditions.
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9
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Abstract
Vibrio is a genus of ubiquitous heterotrophic bacteria found in aquatic environments. Although they are a small percentage of the bacteria in these environments, vibrios can predominate during blooms. Vibrios also play important roles in the degradation of polymeric substances, such as chitin, and in other biogeochemical processes. Vibrios can be found as free-living bacteria, attached to particles, or associated with other organisms in a mutualistic, commensal, or pathogenic relationship. This review focuses on vibrio ecology and genome plasticity, which confers an ability to adapt to new niches and is driven, at least in part, by horizontal gene transfer (HGT). The extent of HGT and its role in pathogen emergence are discussed based on genomic studies of environmental and pathogenic vibrios, mobile genetically encoded virulence factors, and mechanistic studies on the different modes of HGT.
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Affiliation(s)
- Frédérique Le Roux
- Ifremer, Unité Physiologie Fonctionnelle des Organismes Marins, F-29280 Plouzané, France.,Laboratoire de Biologie Intégrative des Modèles Marins, Station Biologique de Roscoff, CNRS UMR 8227, UPMC Paris 06, Sorbonne Universités, F-29688 Roscoff CEDEX, France;
| | - Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland;
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10
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Ahasan MS, Picard J, Elliott L, Kinobe R, Owens L, Ariel E. Evidence of antibiotic resistance in Enterobacteriales isolated from green sea turtles, Chelonia mydas on the Great Barrier Reef. MARINE POLLUTION BULLETIN 2017; 120:18-27. [PMID: 28476351 DOI: 10.1016/j.marpolbul.2017.04.046] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/24/2017] [Accepted: 04/25/2017] [Indexed: 05/20/2023]
Abstract
This study investigated Enterobacteriales and their antimicrobial resistance in green sea turtles captured adjacent to the central Great Barrier Reef (GBR) and proximate to urban development. Cloacal swabs were taken from 73 green turtles between 2015 and 2016. A total of 154 out of 341 Gram-negative bacterial isolates were identified as Enterobacteriales that represent 16 different species from 9 different genera. The dominant isolates were Citrobacter (30.52%), Edwardsiella (21.43%) and Escherichia (12.34%). The resistance against 12 antibiotics belonging to 6 different classes was determined. The isolates showed highest resistance to β-lactam antibiotics (78.57%) followed by quinolone (50%) and tetracycline classes (46.1%). Approximately one-third (37.7%) of the isolates identified exhibited multidrug-resistance. Isolates recovered from rehabilitated turtles were significantly multidrug resistant (p<0.009) compared to isolates from other study sites. These results provide baseline information on antimicrobial resistance while revealing gaps for further research to evaluate the level of pollution in the GBR.
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Affiliation(s)
- Md Shamim Ahasan
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville 4811, Quensland, Australia.
| | - Jacqueline Picard
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville 4811, Quensland, Australia
| | - Lisa Elliott
- AusPhage, 10 Heather Avenue, Rasmussen, Queensland, 4811, Australia
| | - Robert Kinobe
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville 4811, Quensland, Australia
| | - Leigh Owens
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville 4811, Quensland, Australia
| | - Ellen Ariel
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville 4811, Quensland, Australia
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11
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Ghaly TM, Chow L, Asher AJ, Waldron LS, Gillings MR. Evolution of class 1 integrons: Mobilization and dispersal via food-borne bacteria. PLoS One 2017; 12:e0179169. [PMID: 28586403 PMCID: PMC5460862 DOI: 10.1371/journal.pone.0179169] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/24/2017] [Indexed: 11/18/2022] Open
Abstract
Class 1 integrons have played a major role in the global dissemination of antibiotic resistance. Reconstructing the history of class 1 integrons might help us control further spread of antibiotic resistance by understanding how human activities influence microbial evolution. Here we describe a class 1 integron that represents an intermediate stage in the evolutionary history of clinical integrons. It was embedded in a series of nested transposons, carried on an IncP plasmid resident in Enterobacter, isolated from the surface of baby spinach leaves. Based on the structure of this integron, we present a modified hypothesis for integron assembly, where the ancestral clinical class 1 integron was captured from a betaproteobacterial chromosome to form a Tn402-like transposon. This transposon then inserted into a plasmid-borne Tn21-like ancestor while in an environmental setting, possibly a bacterium resident in the phyllosphere. We suggest that the qacE gene cassette, conferring resistance to biocides, together with the mercury resistance operon carried by Tn21, provided a selective advantage when this bacterium made its way into the human commensal flora via food. The integron characterized here was located in Tn6007, which along with Tn6008, forms part of the larger Tn6006 transposon, itself inserted into another transposable element to form the Tn21-like transposon, Tn6005. This element has previously been described from the human microbiota, but with a promoter mutation that upregulates integron cassette expression. This element we describe here is from an environmental bacterium, and supports the hypothesis that the ancestral class 1 integron migrated into anthropogenic settings via foodstuffs. Selection pressures brought about by early antimicrobial agents, including mercury, arsenic and disinfectants, promoted its initial fixation, the acquisition of promoter mutations, and subsequent dissemination into various species and pathogens.
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Affiliation(s)
- Timothy M. Ghaly
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
- * E-mail:
| | - Louise Chow
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Amy J. Asher
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Liette S. Waldron
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Michael R. Gillings
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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12
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Sequential displacement of Type VI Secretion System effector genes leads to evolution of diverse immunity gene arrays in Vibrio cholerae. Sci Rep 2017; 7:45133. [PMID: 28327641 PMCID: PMC5361080 DOI: 10.1038/srep45133] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/17/2017] [Indexed: 11/09/2022] Open
Abstract
Type VI secretion systems (T6SS) enable bacteria to engage neighboring cells in contact-dependent competition. In Vibrio cholerae, three chromosomal clusters each encode a pair of effector and immunity genes downstream of those encoding the T6SS structural machinery for effector delivery. Different combinations of effector-immunity proteins lead to competition between strains of V. cholerae, which are thought to be protected only from the toxicity of their own effectors. Screening of all publically available V. cholerae genomes showed that numerous strains possess long arrays of orphan immunity genes encoded in the 3' region of their T6SS clusters. Phylogenetic analysis reveals that these genes are highly similar to those found in the effector-immunity pairs of other strains, indicating acquisition by horizontal gene transfer. Extensive genomic comparisons also suggest that successive addition of effector-immunity gene pairs replaces ancestral effectors, yet retains the cognate immunity genes. The retention of old immunity genes perhaps provides protection against nearby kin bacteria in which the old effector was not replaced. This mechanism, combined with frequent homologous recombination, is likely responsible for the high diversity of T6SS effector-immunity gene profiles observed for V. cholerae and closely related species.
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13
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Gatica J, Tripathi V, Green S, Manaia CM, Berendonk T, Cacace D, Merlin C, Kreuzinger N, Schwartz T, Fatta-Kassinos D, Rizzo L, Schwermer CU, Garelick H, Jurkevitch E, Cytryn E. High Throughput Analysis of Integron Gene Cassettes in Wastewater Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:11825-11836. [PMID: 27689892 DOI: 10.1021/acs.est.6b03188] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Integrons are extensively targeted as a proxy for anthropogenic impact in the environment. We developed a novel high-throughput amplicon sequencing pipeline that enables characterization of thousands of integron gene cassette-associated reads, and applied it to acquire a comprehensive overview of gene cassette composition in effluents from wastewater treatment facilities across Europe. Between 38 100 and 172 995 reads per-sample were generated and functionally characterized by screening against nr, SEED, ARDB and β-lactamase databases. Over 75% of the reads were characterized as hypothetical, but thousands were associated with toxin-antitoxin systems, DNA repair, cell membrane function, detoxification and aminoglycoside and β-lactam resistance. Among the reads characterized as β-lactamases, the carbapenemase blaOXA was dominant in most of the effluents, except for Cyprus and Israel where blaGES was also abundant. Quantitative PCR assessment of blaOXA and blaGES genes in the European effluents revealed similar trends to those displayed in the integron amplicon sequencing pipeline described above, corroborating the robustness of this method and suggesting that these integron-associated genes may be excellent targets for source tracking of effluents in downstream environments. Further application of the above analyses revealed several order-of-magnitude reductions in effluent-associated β-lactamase genes in effluent-saturated soils, suggesting marginal persistence in the soil microbiome.
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Affiliation(s)
- Joao Gatica
- The Institute of Soil, Water and Environmental Sciences, The Volcani Center, Agricultural Research Organization, Bet-Dagan, Israel
- The Department of Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot, Israel
| | - Vijay Tripathi
- The Department of Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot, Israel
| | - Stefan Green
- DNA Services Facility, Research Resources Center, University of Illinois at Chicago , Chicago, Illinois 60612, United States
| | - Celia M Manaia
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa , Lisboa, Portugal
| | - Thomas Berendonk
- Faculty of Environmental Sciences, Technische Universität Dresden , Dresden, Germany
| | - Damiano Cacace
- Faculty of Environmental Sciences, Technische Universität Dresden , Dresden, Germany
| | - Christophe Merlin
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol , 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France
- Université de Lorraine, LCPME , UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France
| | - Norbert Kreuzinger
- Institute for Water Quality, Resources and Waste Managment, Technische Universität Wien , Wien, Austria
| | - Thomas Schwartz
- Karlsruhe Institute of Technology , Eggenstein-Leopoldshafen, Germany
| | - Despo Fatta-Kassinos
- Department of Civil and Environmental Engineering and Nireas, International Water Research Center, University of Cyprus , P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Luigi Rizzo
- Department of Civil Engineering, University of Salerno , Salerno, Italy
| | | | - Hemda Garelick
- School of Science and Technology, Middlesex University , London, U.K
| | - Edouard Jurkevitch
- The Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot, Israel
| | - Eddie Cytryn
- The Institute of Soil, Water and Environmental Sciences, The Volcani Center, Agricultural Research Organization, Bet-Dagan, Israel
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14
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Gillings MR. Lateral gene transfer, bacterial genome evolution, and the Anthropocene. Ann N Y Acad Sci 2016; 1389:20-36. [DOI: 10.1111/nyas.13213] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/20/2016] [Accepted: 07/28/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Michael R. Gillings
- Genes to Geoscience Research Centre, Department of Biological Sciences Macquarie University Sydney New South Wales Australia
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15
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Engelstädter J, Harms K, Johnsen PJ. The evolutionary dynamics of integrons in changing environments. ISME JOURNAL 2016; 10:1296-307. [PMID: 26849314 DOI: 10.1038/ismej.2015.222] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/13/2015] [Accepted: 10/16/2015] [Indexed: 11/09/2022]
Abstract
Integrons are genetic elements that are common in bacteria and are hotspots for genome evolution. They facilitate the acquisition and reassembly of gene cassettes encoding a variety of functions, including drug resistance. Despite their importance in clinical settings, the selective forces responsible for the evolution and maintenance of integrons are poorly understood. We present a mathematical model of integron evolution within bacterial populations subject to fluctuating antibiotic exposures. Bacteria carrying a functional integrase that mediates reshuffling of cassette genes and thereby modulates gene expression patterns compete with bacteria without a functional integrase. Our results indicate that for a wide range of parameters, the functional integrase can be stably maintained in the population despite substantial fitness costs. This selective advantage arises because gene-cassette shuffling generates genetic diversity, thus enabling the population to respond rapidly to changing selective pressures. We also show that horizontal gene transfer promotes stable maintenance of the integrase and can also lead to de novo assembly of integrons. Our model generates testable predictions for integron evolution, including loss of functional integrases in stable environments and selection for intermediate gene-shuffling rates in changing environments. Our results highlight the need for experimental studies of integron population biology.
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Affiliation(s)
- Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Klaus Harms
- Faculty of Health Sciences, Department of Pharmacy, UIT - The Arctic University of Norway, Tromsø, Norway.,Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Pål J Johnsen
- Faculty of Health Sciences, Department of Pharmacy, UIT - The Arctic University of Norway, Tromsø, Norway
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16
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Abstract
Integrons are versatile gene acquisition systems commonly found in bacterial genomes. They are ancient elements that are a hot spot for genomic complexity, generating phenotypic diversity and shaping adaptive responses. In recent times, they have had a major role in the acquisition, expression, and dissemination of antibiotic resistance genes. Assessing the ongoing threats posed by integrons requires an understanding of their origins and evolutionary history. This review examines the functions and activities of integrons before the antibiotic era. It shows how antibiotic use selected particular integrons from among the environmental pool of these elements, such that integrons carrying resistance genes are now present in the majority of Gram-negative pathogens. Finally, it examines the potential consequences of widespread pollution with the novel integrons that have been assembled via the agency of human antibiotic use and speculates on the potential uses of integrons as platforms for biotechnology.
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17
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Penesyan A, Gillings M, Paulsen IT. Antibiotic discovery: combatting bacterial resistance in cells and in biofilm communities. Molecules 2015; 20:5286-98. [PMID: 25812150 PMCID: PMC6272253 DOI: 10.3390/molecules20045286] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/11/2015] [Accepted: 03/18/2015] [Indexed: 12/26/2022] Open
Abstract
Bacterial resistance is a rapidly escalating threat to public health as our arsenal of effective antibiotics dwindles. Therefore, there is an urgent need for new antibiotics. Drug discovery has historically focused on bacteria growing in planktonic cultures. Many antibiotics were originally developed to target individual bacterial cells, being assessed in vitro against microorganisms in a planktonic mode of life. However, towards the end of the 20th century it became clear that many bacteria live as complex communities called biofilms in their natural habitat, and this includes habitats within a human host. The biofilm mode of life provides advantages to microorganisms, such as enhanced resistance towards environmental stresses, including antibiotic challenge. The community level resistance provided by biofilms is distinct from resistance mechanisms that operate at a cellular level, and cannot be overlooked in the development of novel strategies to combat infectious diseases. The review compares mechanisms of antibiotic resistance at cellular and community levels in the light of past and present antibiotic discovery efforts. Future perspectives on novel strategies for treatment of biofilm-related infectious diseases are explored.
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Affiliation(s)
- Anahit Penesyan
- Department of Chemistry and Biomolecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia.
| | - Michael Gillings
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia.
| | - Ian T Paulsen
- Department of Chemistry and Biomolecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia.
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18
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Jackson RW, Vinatzer B, Arnold DL, Dorus S, Murillo J. The influence of the accessory genome on bacterial pathogen evolution. Mob Genet Elements 2014; 1:55-65. [PMID: 22016845 DOI: 10.4161/mge.1.1.16432] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/09/2011] [Accepted: 05/10/2011] [Indexed: 01/15/2023] Open
Abstract
Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens' frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorize the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution.
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Affiliation(s)
- Robert W Jackson
- School of Biological Sciences; University of Reading; Whiteknights; Reading, UK
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19
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Closek CJ, Sunagawa S, DeSalvo MK, Piceno YM, DeSantis TZ, Brodie EL, Weber MX, Voolstra CR, Andersen GL, Medina M. Coral transcriptome and bacterial community profiles reveal distinct Yellow Band Disease states in Orbicella faveolata. ISME JOURNAL 2014; 8:2411-22. [PMID: 24950107 DOI: 10.1038/ismej.2014.85] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 03/30/2014] [Accepted: 04/08/2014] [Indexed: 11/09/2022]
Abstract
Coral diseases impact reefs globally. Although we continue to describe diseases, little is known about the etiology or progression of even the most common cases. To examine a spectrum of coral health and determine factors of disease progression we examined Orbicella faveolata exhibiting signs of Yellow Band Disease (YBD), a widespread condition in the Caribbean. We used a novel combined approach to assess three members of the coral holobiont: the coral-host, associated Symbiodinium algae, and bacteria. We profiled three conditions: (1) healthy-appearing colonies (HH), (2) healthy-appearing tissue on diseased colonies (HD), and (3) diseased lesion (DD). Restriction fragment length polymorphism analysis revealed health state-specific diversity in Symbiodinium clade associations. 16S ribosomal RNA gene microarrays (PhyloChips) and O. faveolata complimentary DNA microarrays revealed the bacterial community structure and host transcriptional response, respectively. A distinct bacterial community structure marked each health state. Diseased samples were associated with two to three times more bacterial diversity. HD samples had the highest bacterial richness, which included components associated with HH and DD, as well as additional unique families. The host transcriptome under YBD revealed a reduced cellular expression of defense- and metabolism-related processes, while the neighboring HD condition exhibited an intermediate expression profile. Although HD tissue appeared visibly healthy, the microbial communities and gene expression profiles were distinct. HD should be regarded as an additional (intermediate) state of disease, which is important for understanding the progression of YBD.
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Affiliation(s)
- Collin J Closek
- 1] Department of Biology, The Pennsylvania State University, University Park, PA, USA [2] School of Natural Sciences, University of California, Merced, CA, USA
| | - Shinichi Sunagawa
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Yvette M Piceno
- Center for Environmental Biotechnology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Eoin L Brodie
- Center for Environmental Biotechnology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Michele X Weber
- 1] Department of Biology, The Pennsylvania State University, University Park, PA, USA [2] School of Natural Sciences, University of California, Merced, CA, USA
| | - Christian R Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Gary L Andersen
- Center for Environmental Biotechnology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mónica Medina
- 1] Department of Biology, The Pennsylvania State University, University Park, PA, USA [2] School of Natural Sciences, University of California, Merced, CA, USA
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20
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Takemura AF, Chien DM, Polz MF. Associations and dynamics of Vibrionaceae in the environment, from the genus to the population level. Front Microbiol 2014; 5:38. [PMID: 24575082 PMCID: PMC3920100 DOI: 10.3389/fmicb.2014.00038] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 01/20/2014] [Indexed: 12/02/2022] Open
Abstract
The Vibrionaceae, which encompasses several potential pathogens, including V. cholerae, the causative agent of cholera, and V. vulnificus, the deadliest seafood-borne pathogen, are a well-studied family of marine bacteria that thrive in diverse habitats. To elucidate the environmental conditions under which vibrios proliferate, numerous studies have examined correlations with bulk environmental variables—e.g., temperature, salinity, nitrogen, and phosphate—and association with potential host organisms. However, how meaningful these environmental associations are remains unclear because data are fragmented across studies with variable sampling and analysis methods. Here, we synthesize findings about Vibrio correlations and physical associations using a framework of increasingly fine environmental and taxonomic scales, to better understand their dynamics in the wild. We first conduct a meta-analysis to determine trends with respect to bulk water environmental variables, and find that while temperature and salinity are generally strongly predictive correlates, other parameters are inconsistent and overall patterns depend on taxonomic resolution. Based on the hypothesis that dynamics may better correlate with more narrowly defined niches, we review evidence for specific association with plants, algae, zooplankton, and animals. We find that Vibrio are attached to many organisms, though evidence for enrichment compared to the water column is often lacking. Additionally, contrary to the notion that they flourish predominantly while attached, Vibrio can have, at least temporarily, a free-living lifestyle and even engage in massive blooms. Fine-scale sampling from the water column has enabled identification of such lifestyle preferences for ecologically cohesive populations, and future efforts will benefit from similar analysis at fine genetic and environmental sampling scales to describe the conditions, habitats, and resources shaping Vibrio dynamics.
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Affiliation(s)
- Alison F Takemura
- Parsons Lab for Environmental Science and Engineering, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Diana M Chien
- Parsons Lab for Environmental Science and Engineering, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Martin F Polz
- Parsons Lab for Environmental Science and Engineering, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
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21
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Rapa RA, Labbate M. The function of integron-associated gene cassettes in Vibrio species: the tip of the iceberg. Front Microbiol 2013; 4:385. [PMID: 24367362 PMCID: PMC3856429 DOI: 10.3389/fmicb.2013.00385] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/25/2013] [Indexed: 12/17/2022] Open
Abstract
The integron is a genetic element that incorporates mobile genes termed gene cassettes into a reserved genetic site via site-specific recombination. It is best known for its role in antibiotic resistance with one type of integron, the class 1 integron, a major player in the dissemination of antibiotic resistance genes across Gram negative pathogens and commensals. However, integrons are ancient structures with over 100 classes (including class 1) present in bacteria from the broader environment. While, the class 1 integron is only one example of an integron being mobilized into the clinical environment, it is by far the most successful. Unlike clinical class 1 integrons which are largely found on plasmids, other integron classes are found on the chromosomes of bacteria and carry diverse gene cassettes indicating a non-antibiotic resistance role(s). However, there is very limited knowledge on what these alternative roles are. This is particularly relevant to Vibrio species where gene cassettes make up approximately 1-3% of their entire genome. In this review, we discuss how emphasis on class 1 integron research has resulted in a limited understanding by the wider research community on the role of integrons in the broader environment. This has the capacity to be counterproductive in solving or improving the antibiotic resistance problem into the future. Furthermore, there is still a significant lack of knowledge on how gene cassettes in Vibrio species drive adaptation and evolution. From research in Vibrio rotiferianus DAT722, new insight into how gene cassettes affect cellular physiology offers new alternative roles for the gene cassette resource. At least a subset of gene cassettes are involved in host surface polysaccharide modification suggesting that gene cassettes may be important in processes such as bacteriophage resistance, adhesion/biofilm formation, protection from grazers and bacterial aggregation.
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Affiliation(s)
- Rita A Rapa
- ithree Institute, University of Technology Sydney, NSW, Australia ; Department of Medical and Molecular Biosciences, University of Technology Sydney, NSW, Australia
| | - Maurizio Labbate
- ithree Institute, University of Technology Sydney, NSW, Australia ; Department of Medical and Molecular Biosciences, University of Technology Sydney, NSW, Australia
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22
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Quantitative and qualitative impact of hospital effluent on dissemination of the integron pool. ISME JOURNAL 2013; 8:768-77. [PMID: 24152716 DOI: 10.1038/ismej.2013.189] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 09/19/2013] [Accepted: 09/22/2013] [Indexed: 01/19/2023]
Abstract
There is increasing evidence that human activity, and especially the resulting effluent, has a major role in the dissemination of bacterial antibiotic-resistance determinants in the environment. Hospitals are the major antibiotic consumers and thus facilitate the spread of antibiotic resistance. Questions are increasingly being raised about the management of hospital effluents, but their involvement in antibiotic-resistance dissemination has never been assessed. Integrons are a paradigm of genetic transfer between the environmental resistome and both commensal and pathogenic bacteria. In order to assess the impact of hospital activities on antibiotic-resistance dissemination in the environment, we monitored integrons and their gene cassettes in hospital effluents, and their release in the environment. We found that bacterial communities present in a hospital effluent contained a high proportion of integrons. In terms of both their gene cassette diversity and gene cassette arrays, the urban effluent and municipal wastewater treatment plant (WWTP) influent were most similar, whereas the hospital effluent and recirculation sludge exhibited very specific patterns. We found that anthropogenic activities led to the release of abundant integrons and antibiotic-resistance gene cassettes, but we observed no specific impact of hospital activities on the receiving environment. Furthermore, although the WWTP did not reduce the normalized integron copy number, it reduced the diversity of gene cassette arrays contained in the raw wastewater, underlining the effect of the biological treatment on the anthropogenic integron pool arriving at the WWTP.
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23
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Johnson CN. Fitness factors in vibrios: a mini-review. MICROBIAL ECOLOGY 2013; 65:826-851. [PMID: 23306394 DOI: 10.1007/s00248-012-0168-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
Vibrios are Gram-negative curved bacilli that occur naturally in marine, estuarine, and freshwater systems. Some species include human and animal pathogens, and some vibrios are necessary for natural systems, including the carbon cycle and osmoregulation. Countless in vivo and in vitro studies have examined the interactions between vibrios and their environment, including molecules, cells, whole animals, and abiotic substrates. Many studies have characterized virulence factors, attachment factors, regulatory factors, and antimicrobial resistance factors, and most of these factors impact the organism's fitness regardless of its external environment. This review aims to identify common attributes among factors that increase fitness in various environments, regardless of whether the environment is an oyster, a rabbit, a flask of immortalized mammalian cells, or a planktonic chitin particle. This review aims to summarize findings published thus far to encapsulate some of the basic similarities among the many vibrio fitness factors and how they frame our understanding of vibrio ecology. Factors representing these similarities include hemolysins, capsular polysaccharides, flagella, proteases, attachment factors, type III secretion systems, chitin binding proteins, iron acquisition systems, and colonization factors.
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Affiliation(s)
- Crystal N Johnson
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA, USA.
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24
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Krediet CJ, Ritchie KB, Paul VJ, Teplitski M. Coral-associated micro-organisms and their roles in promoting coral health and thwarting diseases. Proc Biol Sci 2013; 280:20122328. [PMID: 23363627 DOI: 10.1098/rspb.2012.2328] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Over the last decade, significant advances have been made in characterization of the coral microbiota. Shifts in its composition often correlate with the appearance of signs of diseases and/or bleaching, thus suggesting a link between microbes, coral health and stability of reef ecosystems. The understanding of interactions in coral-associated microbiota is informed by the on-going characterization of other microbiomes, which suggest that metabolic pathways and functional capabilities define the 'core' microbiota more accurately than the taxonomic diversity of its members. Consistent with this hypothesis, there does not appear to be a consensus on the specificity in the interactions of corals with microbial commensals, even though recent studies report potentially beneficial functions of the coral-associated bacteria. They cycle sulphur, fix nitrogen, produce antimicrobial compounds, inhibit cell-to-cell signalling and disrupt virulence in opportunistic pathogens. While their beneficial functions have been documented, it is not certain whether or how these microbes are selected by the hosts. Therefore, understanding the role of innate immunity, signal and nutrient exchange in the establishment of coral microbiota and in controlling its functions will probably reveal ancient, evolutionarily conserved mechanisms that dictate the outcomes of host-microbial interactions, and impact the resilience of the host.
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Affiliation(s)
- Cory J Krediet
- Interdisciplinary Ecology, University of Florida-IFAS, Gainesville, FL 32610, USA
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25
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Wu YW, Doak TG, Ye Y. The gain and loss of chromosomal integron systems in the Treponema species. BMC Evol Biol 2013; 13:16. [PMID: 23339550 PMCID: PMC3607928 DOI: 10.1186/1471-2148-13-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 01/11/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Integron systems are now recognized as important agents of bacterial evolution and are prevalent in most environments. One of the human pathogens known to harbor chromosomal integrons, the Treponema spirochetes are the only clade among spirochete species found to carry integrons. With the recent release of many new Treponema genomes, we were able to study the distribution of chromosomal integrons in this genus. RESULTS We find that the Treponema spirochetes implicated in human periodontal diseases and those isolated from cow and swine intestines contain chromosomal integrons, but not the Treponema species isolated from termite guts. By examining the species tree of selected spirochetes (based on 31 phylogenetic marker genes) and the phylogenetic tree of predicted integron integrases, and assisted by our analysis of predicted integron recombination sites, we found that all integron systems identified in Treponema spirochetes are likely to have evolved from a common ancestor--a horizontal gain into the clade. Subsequent to this event, the integron system was lost in the branch leading to the speciation of T. pallidum and T. phagedenis (the Treponema sps. implicated in sexually transmitted diseases). We also find that the lengths of the integron attC sites shortened through Treponema speciation, and that the integron gene cassettes of T. denticola are highly strain specific. CONCLUSIONS This is the first comprehensive study to characterize the chromosomal integron systems in Treponema species. By characterizing integron distribution and cassette contents in the Treponema sps., we link the integrons to the speciation of the various species, especially to the pathogens T. pallidum and T. phagedenis.
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Affiliation(s)
- Yu-Wei Wu
- School of Informatics and Computing, Indiana University, Bloomington, IN 47408, USA
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Gillings MR, Stokes H. Are humans increasing bacterial evolvability? Trends Ecol Evol 2012; 27:346-52. [DOI: 10.1016/j.tree.2012.02.006] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 02/21/2012] [Accepted: 02/28/2012] [Indexed: 12/01/2022]
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Oral spirochetes implicated in dental diseases are widespread in normal human subjects and carry extremely diverse integron gene cassettes. Appl Environ Microbiol 2012; 78:5288-96. [PMID: 22635997 DOI: 10.1128/aem.00564-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The NIH Human Microbiome Project (HMP) has produced several hundred metagenomic data sets, allowing studies of the many functional elements in human-associated microbial communities. Here, we survey the distribution of oral spirochetes implicated in dental diseases in normal human individuals, using recombination sites associated with the chromosomal integron in Treponema genomes, taking advantage of the multiple copies of the integron recombination sites (repeats) in the genomes, and using a targeted assembly approach that we have developed. We find that integron-containing Treponema species are present in ∼80% of the normal human subjects included in the HMP. Further, we are able to de novo assemble the integron gene cassettes using our constrained assembly approach, which employs a unique application of the de Bruijn graph assembly information; most of these cassette genes were not assembled in whole-metagenome assemblies and could not be identified by mapping sequencing reads onto the known reference Treponema genomes due to the dynamic nature of integron gene cassettes. Our study significantly enriches the gene pool known to be carried by Treponema chromosomal integrons, totaling 826 (598 97% nonredundant) genes. We characterize the functions of these gene cassettes: many of these genes have unknown functions. The integron gene cassette arrays found in the human microbiome are extraordinarily dynamic, with different microbial communities sharing only a small number of common genes.
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Barott KL, Rodriguez-Mueller B, Youle M, Marhaver KL, Vermeij MJA, Smith JE, Rohwer FL. Microbial to reef scale interactions between the reef-building coral Montastraea annularis and benthic algae. Proc Biol Sci 2012; 279:1655-64. [PMID: 22090385 PMCID: PMC3282354 DOI: 10.1098/rspb.2011.2155] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 10/27/2011] [Indexed: 12/19/2022] Open
Abstract
Competition between reef-building corals and benthic algae is of key importance for reef dynamics. These interactions occur on many spatial scales, ranging from chemical to regional. Using microprobes, 16S rDNA pyrosequencing and underwater surveys, we examined the interactions between the reef-building coral Montastraea annularis and four types of benthic algae. The macroalgae Dictyota bartayresiana and Halimeda opuntia, as well as a mixed consortium of turf algae, caused hypoxia on the adjacent coral tissue. Turf algae were also associated with major shifts in the bacterial communities at the interaction zones, including more pathogens and virulence genes. In contrast to turf algae, interactions with crustose coralline algae (CCA) and M. annularis did not appear to be antagonistic at any scale. These zones were not hypoxic, the microbes were not pathogen-like and the abundance of coral-CCA interactions was positively correlated with per cent coral cover. We propose a model in which fleshy algae (i.e. some species of turf and fleshy macroalgae) alter benthic competition dynamics by stimulating bacterial respiration and promoting invasion of virulent bacteria on corals. This gives fleshy algae a competitive advantage over corals when human activities, such as overfishing and eutrophication, remove controls on algal abundance. Together, these results demonstrate the intricate connections and mechanisms that structure coral reefs.
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Affiliation(s)
- Katie L Barott
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
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Stalder T, Barraud O, Casellas M, Dagot C, Ploy MC. Integron involvement in environmental spread of antibiotic resistance. Front Microbiol 2012; 3:119. [PMID: 22509175 PMCID: PMC3321497 DOI: 10.3389/fmicb.2012.00119] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 03/13/2012] [Indexed: 11/13/2022] Open
Abstract
The spread of antibiotic-resistant bacteria is a growing problem and a public health issue. In recent decades, various genetic mechanisms involved in the spread of resistance genes among bacteria have been identified. Integrons - genetic elements that acquire, exchange, and express genes embedded within gene cassettes (GC) - are one of these mechanisms. Integrons are widely distributed, especially in Gram-negative bacteria; they are carried by mobile genetic elements, plasmids, and transposons, which promote their spread within bacterial communities. Initially studied mainly in the clinical setting for their involvement in antibiotic resistance, their role in the environment is now an increasing focus of attention. The aim of this review is to provide an in-depth analysis of recent studies of antibiotic-resistance integrons in the environment, highlighting their potential involvement in antibiotic-resistance outside the clinical context. We will focus particularly on the impact of human activities (agriculture, industries, wastewater treatment, etc.).
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Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus. ISME JOURNAL 2011; 6:835-46. [PMID: 22158392 DOI: 10.1038/ismej.2011.154] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sea surface temperatures (SST) are rising because of global climate change. As a result, pathogenic Vibrio species that infect humans and marine organisms during warmer summer months are of growing concern. Coral reefs, in particular, are already experiencing unprecedented degradation worldwide due in part to infectious disease outbreaks and bleaching episodes that are exacerbated by increasing SST. For example, Vibrio coralliilyticus, a globally distributed bacterium associated with multiple coral diseases, infects corals at temperatures above 27 °C. The mechanisms underlying this temperature-dependent pathogenicity, however, are unknown. In this study, we identify potential virulence mechanisms using whole genome sequencing of V. coralliilyticus ATCC (American Type Culture Collection) BAA-450. Furthermore, we demonstrate direct temperature regulation of numerous virulence factors using proteomic analysis and bioassays. Virulence factors involved in motility, host degradation, secretion, antimicrobial resistance and transcriptional regulation are upregulated at the higher virulent temperature of 27 °C, concurrent with phenotypic changes in motility, antibiotic resistance, hemolysis, cytotoxicity and bioluminescence. These results provide evidence that temperature regulates multiple virulence mechanisms in V. coralliilyticus, independent of abundance. The ecological and biological significance of this temperature-dependent virulence response is reinforced by climate change models that predict tropical SST to consistently exceed 27 °C during the spring, summer and fall seasons. We propose V. coralliilyticus as a model Gram-negative bacterium to study temperature-dependent pathogenicity in Vibrio-related diseases.
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Gestal AM, Liew EF, Coleman NV. Natural transformation with synthetic gene cassettes: new tools for integron research and biotechnology. Microbiology (Reading) 2011; 157:3349-3360. [DOI: 10.1099/mic.0.051623-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Integrons are genetic elements that can capture and express genes packaged as gene cassettes. Here we report new methods that allow integrons to be studied and manipulated in their native bacterial hosts. Synthetic gene cassettes encoding gentamicin resistance (aadB) and green fluorescence (gfp), or lactose metabolism (lacZY), were made by PCR and self-ligation, converted to large tandem arrays by multiple displacement amplification, and introduced into Escherichia coli or Pseudomonas stutzeri strains via electroporation or natural transformation. Recombinants (GmR or Lac+) were obtained at frequencies ranging from 101 to 106 c.f.u. (µg DNA)−1. Cassettes were integrated by site-specific recombination at the integron attI site in nearly all cases examined (370/384), including both promoterless and promoter-containing cassettes. Fluorometric analysis of gfp-containing recombinants revealed that expression levels from the integron-associated promoter PC were five- to 10-fold higher in the plasmid-borne integron In3 compared with the P. stutzeri chromosomal integrons. Integration of lacZY cassettes into P. stutzeri integrons allowed the bacteria to grow on lactose, and the lacZY gene cassette was stably maintained in the absence of selection. This study is believed to be the first to show natural transformation by gene cassettes, and integron-mediated capture of catabolic gene cassettes.
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Affiliation(s)
- Alicia M. Gestal
- School of Molecular Bioscience, Building G08, The University of Sydney, NSW 2006, Australia
| | - Elissa F. Liew
- School of Molecular Bioscience, Building G08, The University of Sydney, NSW 2006, Australia
| | - Nicholas V. Coleman
- School of Molecular Bioscience, Building G08, The University of Sydney, NSW 2006, Australia
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Labbate M, Boucher Y, Chowdhury PR, Stokes HW. Integration of a laterally acquired gene into a cell network important for growth in a strain of Vibrio rotiferianus. BMC Microbiol 2011; 11:253. [PMID: 22093957 PMCID: PMC3262767 DOI: 10.1186/1471-2180-11-253] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 11/18/2011] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Lateral Gene Transfer (LGT) is a major contributor to bacterial evolution and up to 25% of a bacterium's genome may have been acquired by this process over evolutionary periods of time. Successful LGT requires both the physical transfer of DNA and its successful incorporation into the host cell. One system that contributes to this latter step by site-specific recombination is the integron. Integrons are found in many diverse bacterial Genera and is a genetic system ubiquitous in vibrios that captures mobile DNA at a dedicated site. The presence of integron-associated genes, contained within units of mobile DNA called gene cassettes makes up a substantial component of the vibrio genome (1-3%). Little is known about the role of this system since the vast majority of genes in vibrio arrays are highly novel and functions cannot be ascribed. It is generally regarded that strain-specific mobile genes cannot be readily integrated into the cellular machinery since any perturbation of core metabolism is likely to result in a loss of fitness. RESULTS In this study, at least one mobile gene contained within the Vibrio rotiferianus strain DAT722, but lacking close relatives elsewhere, is shown to greatly reduce host fitness when deleted and tested in growth assays. The precise role of the mobile gene product is unknown but impacts on the regulation of outermembrane porins. This demonstrates that strain specific laterally acquired mobile DNA can be integrated rapidly into bacterial networks such that it becomes advantageous for survival and adaptation in changing environments. CONCLUSIONS Mobile genes that are highly strain specific are generally believed to act in isolation. This is because perturbation of existing cell machinery by the acquisition of a new gene by LGT is highly likely to lower fitness. In contrast, we show here that at least one mobile gene, apparently unique to a strain, encodes a product that has integrated into central cellular metabolic processes such that it greatly lowers fitness when lost under those conditions likely to be commonly encountered for the free living cell. This has ramifications for our understanding of the role mobile gene encoded products play in the cell from a systems biology perspective.
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Affiliation(s)
- Maurizio Labbate
- The ithree institute, University of Technology, Sydney. Harris Street and Broadway, Sydney, NSW 2007, Australia
| | - Yan Boucher
- Department of Biological Sciences, University of Alberta. 110 St NW Edmonton, Alberta, T6G 2R3, Canada
| | - Piklu Roy Chowdhury
- The ithree institute, University of Technology, Sydney. Harris Street and Broadway, Sydney, NSW 2007, Australia
| | - Hatch W Stokes
- The ithree institute, University of Technology, Sydney. Harris Street and Broadway, Sydney, NSW 2007, Australia
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