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Comparative Genomic Analysis of Virulent Vibrio (Listonella) anguillarum Serotypes Revealed Genetic Diversity and Genomic Signatures in the O-Antigen Biosynthesis Gene Cluster. Microorganisms 2023; 11:microorganisms11030792. [PMID: 36985365 PMCID: PMC10059132 DOI: 10.3390/microorganisms11030792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/22/2023] Open
Abstract
Vibrio anguillarum is the most frequent pathogen affecting fish worldwide. The only known virulent strains of V. anguillarum are serotypes O1, O2, and O3. Genetic differences between the serotypes that could shed insight on the evolution and serotype differences of this marine pathogen are unknown. Here, we fully sequenced and characterized a strain of V. anguillarum O1 (J382) isolated from winter steelhead trout (Oncorhynchus mykiss irideus) in British Columbia, Canada. Koch’s postulates using the O1 strain were replicated in naïve lumpfish (Cyclopterus lumpus) and compared to O2. Phenotypic and genotypic comparisons were conducted for serotypes O1, O2, and O3, using biochemical tests and bioinformatic tools, respectively. The genome of V. anguillarum O1 (J382) contains two chromosomes (3.13 Mb and 1.03 Mb) and two typical pJM1-like plasmids (65,573 and 76,959 bp). Furthermore, V. anguillarum O1 (J382) displayed resistance to colistin sulphate, which differs from serotype O2 and could be attributed to the presence of the ugd gene. Comparative genomic analysis, among the serotypes, showed that intra-species evolution is driven by insertion sequences, bacteriophages, and a different repertoire of putative ncRNAs. Genetic heterogeneity in the O-antigen biosynthesis gene cluster is characterized by the absence or the presence of unique genes, which could result in differences in the immune evasion mechanisms employed by the respective serotypes. This study contributes to understanding the genetic differences among V. anguillarum serovars and their evolution.
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How Do Transposable Elements Activate Expression of Transcriptionally Silent Antibiotic Resistance Genes? Int J Mol Sci 2022; 23:ijms23158063. [PMID: 35897639 PMCID: PMC9330008 DOI: 10.3390/ijms23158063] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/17/2022] [Accepted: 07/20/2022] [Indexed: 02/06/2023] Open
Abstract
The rapidly emerging phenomenon of antibiotic resistance threatens to substantially reduce the efficacy of available antibacterial therapies. Dissemination of resistance, even between phylogenetically distant bacterial species, is mediated mainly by mobile genetic elements, considered to be natural vectors of horizontal gene transfer. Transposable elements (TEs) play a major role in this process—due to their highly recombinogenic nature they can mobilize adjacent genes and can introduce them into the pool of mobile DNA. Studies investigating this phenomenon usually focus on the genetic load of transposons and the molecular basis of their mobility. However, genes introduced into evolutionarily distant hosts are not necessarily expressed. As a result, bacterial genomes contain a reservoir of transcriptionally silent genetic information that can be activated by various transposon-related recombination events. The TEs themselves along with processes associated with their transposition can introduce promoters into random genomic locations. Thus, similarly to integrons, they have the potential to convert dormant genes into fully functional antibiotic resistance determinants. In this review, we describe the genetic basis of such events and by extension the mechanisms promoting the emergence of new drug-resistant bacterial strains.
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Mangar P, Barman P, Kumar A, Saha A, Saha D. Detection of Virulence-Associated Genes and in vitro Gene Transfer From Aeromonas sp. Isolated From Aquatic Environments of Sub-himalayan West Bengal. Front Vet Sci 2022; 9:887174. [PMID: 35754535 PMCID: PMC9230572 DOI: 10.3389/fvets.2022.887174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/03/2022] [Indexed: 11/23/2022] Open
Abstract
Aeromonas is omnipresent in aquatic environments and cause disease within a wide host range. A total of thirty-four isolates from water samples of small fish farms were identified as Aeromonas based on biochemical characteristics and 16S rRNA gene sequence. A total of six virulent factors were analyzed which indicated 100% of isolates as beta-haemolytic and proteolytic, whereas 44.1, 38.2, and 70.6% of isolates produced DNAse, siderophore, and amylase, respectively. Studies on the occurrence of four genetic determinants of virulence factors revealed that aer/haem (haemolytic toxin) and flaA (polar flagella) genes were present in 44.1% of strains whereas ascV (type 3 secretion system) and aspA (serine protease) genes were detected in 21.5 and 8.82% of strains, respectively. Fish (Anabas testudineus) challenge studies showed that the isolate GP3 (Aeromonas veronii) bearing five virulent factors with the combination of aer/haem+/ascV+/fla+ genes induced severe lesions leading to 100% of mortality. In contrast, RB7 possessing four virulence factors and three genes (aer/haem+/ascV+/aspA+) could not produce severe lesions and any mortality indicating the absence of correlation between the virulence factors, its genes, and the pathogenicity in fishes. GP3 was cytotoxic to human liver cell line (WRL-68) in trypan blue dye exclusion assay. The 431 bp aer/haem gene of GP3 was transferable to E. coli Dh5α with a conjugational efficiency of 0.394 × 10–4 transconjugants per recipient cell. The transfer was confirmed by PCR and by the presence of 23-kb plasmids in both donor and transconjugants. Therefore, the occurrence of mobile genetic elements bearing virulence-associated genes in Aeromonas indicates the need for periodic monitoring of the aquatic habitat to prevent disease outbreaks.
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Affiliation(s)
- Preeti Mangar
- Department of Botany, University of North Bengal, Siliguri, India
| | - Partha Barman
- Department of Biotechnology, University of North Bengal, Siliguri, India
| | - Anoop Kumar
- Department of Biotechnology, University of North Bengal, Siliguri, India
| | - Aniruddha Saha
- Department of Botany, University of North Bengal, Siliguri, India
| | - Dipanwita Saha
- Department of Biotechnology, University of North Bengal, Siliguri, India
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Bekaert M, Goffin N, McMillan S, Desbois AP. Essential Genes of Vibrio anguillarum and Other Vibrio spp. Guide the Development of New Drugs and Vaccines. Front Microbiol 2021; 12:755801. [PMID: 34745063 PMCID: PMC8564382 DOI: 10.3389/fmicb.2021.755801] [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: 08/09/2021] [Accepted: 09/24/2021] [Indexed: 01/04/2023] Open
Abstract
Essential genes in bacterial pathogens are potential drug targets and vaccine candidates because disrupting their function is lethal. The development of new antibiotics, in addition to effective prevention measures such as vaccination, contributes to addressing the global problem of bacterial antibiotic resistance. The aim of this present study was to determine the essential genes of Vibrio anguillarum, a bacterial pathogen of aquatic animals, as a means to identify putative targets for novel drugs and to assist the prioritisation of potential vaccine candidates. Essential genes were characterised by a Tn-seq approach using the TnSC189 mariner transposon to construct a library of 52,662 insertion mutants. In total, 329 essential genes were identified, with 34.7% found within the core genome of this species; each of these genes represents a strong potential drug target. Seven essential gene products were predicted to reside in the cell membrane or be released extracellularly, thus serving as putative vaccine candidates. Comparison to essential gene data from five other studies of Vibrio species revealed 13 proteins to be conserved across the studies, while 25 genes were specific to V. anguillarum and not found to be essential in the other Vibrio spp. This study provides new information on the essential genes of Vibrio species and the methodology may be applied to other pathogens to guide the development of new drugs and vaccines, which will assist efforts to counter antibiotic resistance.
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Affiliation(s)
- Michaël Bekaert
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Nikki Goffin
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Stuart McMillan
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Andrew P Desbois
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
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Chibani CM, Roth O, Liesegang H, Wendling CC. Genomic variation among closely related Vibrio alginolyticus strains is located on mobile genetic elements. BMC Genomics 2020; 21:354. [PMID: 32393168 PMCID: PMC7216594 DOI: 10.1186/s12864-020-6735-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/14/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Species of the genus Vibrio, one of the most diverse bacteria genera, have undergone niche adaptation followed by clonal expansion. Niche adaptation and ultimately the formation of ecotypes and speciation in this genus has been suggested to be mainly driven by horizontal gene transfer (HGT) through mobile genetic elements (MGEs). Our knowledge about the diversity and distribution of Vibrio MGEs is heavily biased towards human pathogens and our understanding of the distribution of core genomic signatures and accessory genes encoded on MGEs within specific Vibrio clades is still incomplete. We used nine different strains of the marine bacterium Vibrio alginolyticus isolated from pipefish in the Kiel-Fjord to perform a multiscale-comparative genomic approach that allowed us to investigate [1] those genomic signatures that characterize a habitat-specific ecotype and [2] the source of genomic variation within this ecotype. RESULTS We found that the nine isolates from the Kiel-Fjord have a closed-pangenome and did not differ based on core-genomic signatures. Unique genomic regions and a unique repertoire of MGEs within the Kiel-Fjord isolates suggest that the acquisition of gene-blocks by HGT played an important role in the evolution of this ecotype. Additionally, we found that ~ 90% of the genomic variation among the nine isolates is encoded on MGEs, which supports ongoing theory that accessory genes are predominately located on MGEs and shared by HGT. Lastly, we could show that these nine isolates share a unique virulence and resistance profile which clearly separates them from all other investigated V. alginolyticus strains and suggests that these are habitat-specific genes, required for a successful colonization of the pipefish, the niche of this ecotype. CONCLUSION We conclude that all nine V. alginolyticus strains from the Kiel-Fjord belong to a unique ecotype, which we named the Kiel-alginolyticus ecotype. The low sequence variation of the core-genome in combination with the presence of MGE encoded relevant traits, as well as the presence of a suitable niche (here the pipefish), suggest, that this ecotype might have evolved from a clonal expansion following HGT driven niche-adaptation.
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Affiliation(s)
- Cynthia Maria Chibani
- Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University, 37077, Göttingen, Germany
- Institute for Microbiology and Genetics, Georg-August University Goettingen, Grisebachstr. 8, 37077, Goettingen, Germany
| | - Olivia Roth
- GEOMAR, Helmholtz Centre for Ocean Research, Marine Evolutionary Ecology, Duesternbrooker Weg 20, 24105, Kiel, Germany
| | - Heiko Liesegang
- Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University, 37077, Göttingen, Germany
| | - Carolin Charlotte Wendling
- GEOMAR, Helmholtz Centre for Ocean Research, Marine Evolutionary Ecology, Duesternbrooker Weg 20, 24105, Kiel, Germany.
- Department of Environmental Systems Science, ETH Zürich, Universitätsstraße 16, 8092, Zürich, Switzerland.
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Akter T, Lindegaard M, Pedersen K, Strube ML, Ronco T, Dalsgaard I. Sequence Analysis of Plasmids in Vibrio anguillarum from Different Fish and Locations. JOURNAL OF AQUATIC ANIMAL HEALTH 2020; 32:21-27. [PMID: 31986229 DOI: 10.1002/aah.10093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/09/2019] [Indexed: 06/10/2023]
Abstract
The genetic diversity of Vibrio anguillarum pJM1-like plasmids was investigated. Plasmids were isolated from 18 V. anguillarum serovar O1 strains collected from different geographic locations and fish species. The plasmids were sequenced and compared with the complete sequence of the published virulence plasmid pJM1. All 18 strains contained pJM1-like plasmids with approximately 65 kbp and all plasmids encoded the virulence genes responsible for the anguibactin iron sequestering system. The plasmids were highly conserved but minor differences were observed in some genes. A single nucleotide polymorphisms (SNPs) analysis showed 0-11 nucleotide variations between each of the 18 plasmids and the pJM1 plasmid. Compared with the sequence of pJM1, nonsynonymous SNPs were identified in fatC, angR, angL, pJM1_p19, and angE. In particular, a mutation found in 15 out of 18 sequenced plasmids in angR has previously been linked to hyperproduction of anguibactin and was found in all the European isolates. However, overall the pJM1-like plasmids isolated from V. anguillarum serovar O1 exhibited a high degree of conservation regardless of their geographical origin or fish species.
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Affiliation(s)
- Tasmina Akter
- National Veterinary Institute, Technical University of Denmark, Anker Engelunds Vej 1, DK-2800, Kongens Lyngby, Denmark
| | - Mikkel Lindegaard
- National Veterinary Institute, Technical University of Denmark, Anker Engelunds Vej 1, DK-2800, Kongens Lyngby, Denmark
| | - Karl Pedersen
- National Veterinary Institute, Technical University of Denmark, Anker Engelunds Vej 1, DK-2800, Kongens Lyngby, Denmark
| | - Mikael L Strube
- National Veterinary Institute, Technical University of Denmark, Anker Engelunds Vej 1, DK-2800, Kongens Lyngby, Denmark
| | - Troels Ronco
- National Veterinary Institute, Technical University of Denmark, Anker Engelunds Vej 1, DK-2800, Kongens Lyngby, Denmark
| | - Inger Dalsgaard
- National Veterinary Institute, Technical University of Denmark, Anker Engelunds Vej 1, DK-2800, Kongens Lyngby, Denmark
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7
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Batallones V, Fernandez J, Farthing B, Shoemaker J, Qian KL, Phan K, Fung E, Rivera A, Van K, de la Cruz F, Ferreri AJ, Burinski K, Zhang J, Lizarraga V, Doan K, Rocha K, Traglia G, Ramirez MS, Tolmasky ME. Disruption of hmgA by DNA Duplication is Responsible for Hyperpigmentation in a Vibrio anguillarum Strain. Sci Rep 2019; 9:14589. [PMID: 31601906 PMCID: PMC6787238 DOI: 10.1038/s41598-019-51126-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 09/10/2019] [Indexed: 11/24/2022] Open
Abstract
Vibrio anguillarum 531A, isolated from a diseased fish in the Atlantic Ocean, is a mixture composed of about 95 and 5% of highly pigmented cells (strain 531Ad) and cells with normal levels of pigmentation (strain 531Ac), respectively. Analysis of the V. anguillarum 531Ad DNA region encompassing genes involved in the tyrosine metabolism showed a 410-bp duplication within the hmgA gene that results in a frameshift and early termination of translation of the homogentisate 1,2-dioxygenase. We hypothesized that this mutation results in accumulation of homogentisate that is oxidized and polymerized to produce pyomelanin. Introduction in E. coli of recombinant clones carrying the V. anguillarum hppD (4-hydroxyphenylpyruvate-dioxygenase), and a mutated hmgA produced brown colored colonies. Complementation with a recombinant clone harboring hmgA restored the original color to the colonies confirming that in the absence of homogentisate 1,2-dioxygenase the intermediary in tyrosine catabolism homogentisate accumulates and undergoes nonenzymatic oxidation and polymerization resulting in high amounts of the brown pigment. Whole-genome sequence analysis showed that V. anguillarum 531 Ac and 531Ad differ in the hmgA gene mutation and 23 mutations, most of which locate to intergenic regions and insertion sequences.
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Affiliation(s)
- Veronica Batallones
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Jennifer Fernandez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Brett Farthing
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Jordan Shoemaker
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Keizen Li Qian
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Kimberly Phan
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Eric Fung
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Ashley Rivera
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Kevin Van
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Francesca de la Cruz
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Alexandra J Ferreri
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Krystle Burinski
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Jackie Zhang
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Vicente Lizarraga
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Kevin Doan
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Kenneth Rocha
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - German Traglia
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Maria S Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Marcelo E Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA.
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8
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Boiteau RM, Fansler SJ, Farris Y, Shaw JB, Koppenaal DW, Pasa-Tolic L, Jansson JK. Siderophore profiling of co-habitating soil bacteria by ultra-high resolution mass spectrometry. Metallomics 2019; 11:166-175. [DOI: 10.1039/c8mt00252e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Calcareous soil microbes complete for scarce iron by synthesizing diverse suites of siderophores detectable by ultra-high resolution mass spectrometry.
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Affiliation(s)
- Rene M. Boiteau
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
- College of Earth, Ocean, Atmospheric Sciences
| | - Sarah J. Fansler
- Biological Sciences Division
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Yuliya Farris
- College of Earth, Ocean, Atmospheric Sciences
- Oregon State University
- Corvallis
- USA
| | - Jared B. Shaw
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - David W. Koppenaal
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Ljiljana Pasa-Tolic
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Janet K. Jansson
- Biological Sciences Division
- Pacific Northwest National Laboratory
- Richland
- USA
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Thode SK, Rojek E, Kozlowski M, Ahmad R, Haugen P. Distribution of siderophore gene systems on a Vibrionaceae phylogeny: Database searches, phylogenetic analyses and evolutionary perspectives. PLoS One 2018; 13:e0191860. [PMID: 29444108 PMCID: PMC5812596 DOI: 10.1371/journal.pone.0191860] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 01/13/2018] [Indexed: 11/19/2022] Open
Abstract
Siderophores are small molecules synthesized and secreted by bacteria and fungi to scavenge iron. Extracellular ferri-siderohores are recognized by cognate receptors on the cell surface for transport over membranes. Several siderophore systems from Vibrionaceae representatives are known and well understood, e.g., the molecular structure of the siderophore, the biosynthesis gene cluster and pathway, and the gene expression pattern. Less is known about how these systems are distributed among the ~140 Vibrionaceae species, and which evolutionary processes contributed to the present-day distribution. In this work, we compiled existing knowledge on siderophore biosynthesis systems and siderophore receptors from Vibrionaceae and used phylogenetic analyses to investigate their organization, distribution, origin and evolution. Through literature searches, we identified nine different siderophore biosynthesis systems and thirteen siderophore receptors in Vibrionaceae. Homologs were identified by BLAST searches, and the results were mapped onto a Vibrionaceae phylogeny. We identified 81 biosynthetic systems distributed in 45 Vibrionaceae species and 16 unclassified Vibrionaceae strains, and 409 receptors in 89 Vibrionaceae species and 49 unclassified Vibrionaceae strains. The majority of taxa are associated with at least one type of siderophore biosynthesis system, some (e.g., aerobactin and vibrioferrin) of which are widely distributed in the family, whereas others (i.e., bisucaberin and vibriobactin) are found in one lineage. Cognate receptors are found more widespread. Phylogenetic analysis of three siderophore systems (piscibactin, vibrioferrin and aerobactin) show that their present-day distribution can be explained by an old insertion into Vibrionaceae, followed mainly by stable vertical evolution and extensive loss, and some cases of horizontal gene transfers. The present work provides an up to date overview of the distribution of siderophore-based iron acquisition systems in Vibrionaceae, and presents phylogenetic analysis of these systems. Our results suggest that the present-day distribution is a result of several evolutionary processes, such as old and new gene acquisitions, gene loss, and both vertical and horizontal gene transfers.
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Affiliation(s)
- Sunniva Katharina Thode
- Department of Chemistry and Center for Bioinformatics (SfB), Faculty of Science and Technology, UiT − The Arctic University of Norway, Tromsø, Norway
| | - Ewelina Rojek
- Department of Natural Sciences and Technology, Faculty of Education and Natural Sciences, Inland Norway University of Applied Sciences, Hamar, Norway
| | - Mikolaj Kozlowski
- Department of Natural Sciences and Technology, Faculty of Education and Natural Sciences, Inland Norway University of Applied Sciences, Hamar, Norway
| | - Rafi Ahmad
- Department of Natural Sciences and Technology, Faculty of Education and Natural Sciences, Inland Norway University of Applied Sciences, Hamar, Norway
- * E-mail: (PH); (RA)
| | - Peik Haugen
- Department of Chemistry and Center for Bioinformatics (SfB), Faculty of Science and Technology, UiT − The Arctic University of Norway, Tromsø, Norway
- * E-mail: (PH); (RA)
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10
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Vandecraen J, Chandler M, Aertsen A, Van Houdt R. The impact of insertion sequences on bacterial genome plasticity and adaptability. Crit Rev Microbiol 2017; 43:709-730. [PMID: 28407717 DOI: 10.1080/1040841x.2017.1303661] [Citation(s) in RCA: 224] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transposable elements (TE), small mobile genetic elements unable to exist independently of the host genome, were initially believed to be exclusively deleterious genomic parasites. However, it is now clear that they play an important role as bacterial mutagenic agents, enabling the host to adapt to new environmental challenges and to colonize new niches. This review focuses on the impact of insertion sequences (IS), arguably the smallest TE, on bacterial genome plasticity and concomitant adaptability of phenotypic traits, including resistance to antibacterial agents, virulence, pathogenicity and catabolism. The direct consequence of IS transposition is the insertion of one DNA sequence into another. This event can result in gene inactivation as well as in modulation of neighbouring gene expression. The latter is usually mediated by de-repression or by the introduction of a complete or partial promoter located within the element. Furthermore, transcription and transposition of IS are affected by host factors and in some cases by environmental signals offering the host an adaptive strategy and promoting genetic variability to withstand the environmental challenges.
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Affiliation(s)
- Joachim Vandecraen
- a Microbiology Unit, Interdisciplinary Biosciences , Belgian Nuclear Research Centre (SCK•CEN) , Mol , Belgium.,b Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre , Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering , KU Leuven , Leuven , Belgium
| | - Michael Chandler
- c Laboratoire de Microbiologie et Génétique Moléculaires, Centre national de la recherche scientifique , Toulouse , France
| | - Abram Aertsen
- b Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre , Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering , KU Leuven , Leuven , Belgium
| | - Rob Van Houdt
- a Microbiology Unit, Interdisciplinary Biosciences , Belgian Nuclear Research Centre (SCK•CEN) , Mol , Belgium
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11
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Steinum TM, Karataş S, Martinussen NT, Meirelles PM, Thompson FL, Colquhoun DJ. Multilocus Sequence Analysis of Close Relatives Vibrio anguillarum and Vibrio ordalii. Appl Environ Microbiol 2016; 82:5496-504. [PMID: 27371582 PMCID: PMC5007779 DOI: 10.1128/aem.00620-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The genetic heterogeneity of the close relatives Vibrio anguillarum and Vibrio ordalii, both serious pathogens of fish causing extensive losses in aquaculture, was studied. Eight housekeeping genes, i.e., atpA, ftsZ, gapA, gyrB, mreB, rpoA, topA, and pyrH, were partially sequenced in 116 isolates from diverse fish species and geographical areas. The eight genes appear to be under purifying selection, and the genetic diversity in the total data set was estimated to be 0.767 ± 0.026. Our multilocus sequence analysis (MLSA) scheme identified several widespread clonal complexes and resolved the isolates, for the most part, according to serotype. Serotype O2b isolates from diseased cod in Norway, Ireland, and Scotland were found to be extremely homogeneous. Horizontal gene transfer appears to be fairly common within and between clonal complexes. Taken together, MLSA and in silico DNA-DNA hybridization (DDH) calculations suggest that some isolates previously characterized as V ordalii, i.e., 12B09, FF93, FS144, and FS238, are in fact V. anguillarum isolates. The precise taxonomic situation for two isolates from Atlantic cod that display several traits consistent with V. ordalii, i.e., NVI 5286 and NVI 5918, and a single environmental strain that was previously considered to represent V. ordalii, i.e., FF167, is less clear. IMPORTANCE It is still being debated whether V. anguillarum and V ordalii represent separate bacterial species. Our study addresses this issue and elucidates the degree of genetic variability within this group of closely related bacteria, based on a substantial number of isolates. Our results clearly illustrate the existence of different populations among putative V ordalii isolates. On the basis of additional full-length genomic analysis, we conclude that most environmental isolates previously identified as V ordalii lie firmly within the species V. anguillarum While bona fide fish-pathogenic V ordalii isolates display a very close genetic relationship with V. anguillarum, they combine a clearly divergent evolutionary pattern with clear phenotypic differences. The study also highlights the need for further characterization of fish-pathogenic isolates from the northern Atlantic region that share phenotypic characteristics with V. ordalii but are genetically closer to V. anguillarum The retention of taxonomic distinctions between the phenotypically different groups of bacteria is of practical advantage to microbial ecologists and veterinarians.
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Affiliation(s)
- Terje M Steinum
- Department of Genetics and Molecular Biology, Life Sciences Faculty, Istanbul University, Istanbul, Turkey
| | - Süheyla Karataş
- Department of Fish Diseases, Fisheries Faculty, Istanbul University, Istanbul, Turkey
| | | | - Pedro M Meirelles
- Institute of Biology and SAGE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabiano L Thompson
- Institute of Biology and SAGE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Duncan J Colquhoun
- Section for Bacteriology, Norwegian Veterinary Institute, Oslo, Norway Institute for Biology, University of Bergen, Bergen, Norway
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12
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Payne SM, Mey AR, Wyckoff EE. Vibrio Iron Transport: Evolutionary Adaptation to Life in Multiple Environments. Microbiol Mol Biol Rev 2016; 80:69-90. [PMID: 26658001 PMCID: PMC4711184 DOI: 10.1128/mmbr.00046-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Iron is an essential element for Vibrio spp., but the acquisition of iron is complicated by its tendency to form insoluble ferric complexes in nature and its association with high-affinity iron-binding proteins in the host. Vibrios occupy a variety of different niches, and each of these niches presents particular challenges for acquiring sufficient iron. Vibrio species have evolved a wide array of iron transport systems that allow the bacteria to compete for this essential element in each of its habitats. These systems include the secretion and uptake of high-affinity iron-binding compounds (siderophores) as well as transport systems for iron bound to host complexes. Transporters for ferric and ferrous iron not complexed to siderophores are also common to Vibrio species. Some of the genes encoding these systems show evidence of horizontal transmission, and the ability to acquire and incorporate additional iron transport systems may have allowed Vibrio species to more rapidly adapt to new environmental niches. While too little iron prevents growth of the bacteria, too much can be lethal. The appropriate balance is maintained in vibrios through complex regulatory networks involving transcriptional repressors and activators and small RNAs (sRNAs) that act posttranscriptionally. Examination of the number and variety of iron transport systems found in Vibrio spp. offers insights into how this group of bacteria has adapted to such a wide range of habitats.
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Affiliation(s)
- Shelley M Payne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Alexandra R Mey
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Elizabeth E Wyckoff
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
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Holm KO, Nilsson K, Hjerde E, Willassen NP, Milton DL. Complete genome sequence of Vibrio anguillarum strain NB10, a virulent isolate from the Gulf of Bothnia. Stand Genomic Sci 2015; 10:60. [PMID: 26380645 PMCID: PMC4572688 DOI: 10.1186/s40793-015-0060-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 08/17/2015] [Indexed: 11/12/2022] Open
Abstract
Vibrio anguillarum causes a fatal hemorrhagic septicemia in marine fish that leads to great economical losses in aquaculture world-wide. Vibrio anguillarum strain NB10 serotype O1 is a Gram-negative, motile, curved rod-shaped bacterium, isolated from a diseased fish on the Swedish coast of the Gulf of Bothnia, and is slightly halophilic. Strain NB10 is a virulent isolate that readily colonizes fish skin and intestinal tissues. Here, the features of this bacterium are described and the annotation and analysis of its complete genome sequence is presented. The genome is 4,373,835 bp in size, consists of two circular chromosomes and one plasmid, and contains 3,783 protein-coding genes and 129 RNA genes.
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Affiliation(s)
- Kåre Olav Holm
- />Department of Chemistry, Faculty of Science and Technology, UiT: The Arctic University of Norway, 9037 Tromsø, NO Norway
| | - Kristina Nilsson
- />Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Department of Molecular Biology, 901 87 Umeå, SE Sweden
| | - Erik Hjerde
- />Department of Chemistry, Faculty of Science and Technology, UiT: The Arctic University of Norway, 9037 Tromsø, NO Norway
| | - Nils-Peder Willassen
- />Department of Chemistry, Faculty of Science and Technology, UiT: The Arctic University of Norway, 9037 Tromsø, NO Norway
| | - Debra L. Milton
- />Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Department of Molecular Biology, 901 87 Umeå, SE Sweden
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Busschaert P, Frans I, Crauwels S, Zhu B, Willems K, Bossier P, Michiels C, Verstrepen K, Lievens B, Rediers H. Comparative genome sequencing to assess the genetic diversity and virulence attributes of 15 Vibrio anguillarum isolates. JOURNAL OF FISH DISEASES 2015; 38:795-807. [PMID: 25073650 DOI: 10.1111/jfd.12290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/14/2014] [Accepted: 06/19/2014] [Indexed: 06/03/2023]
Abstract
Vibrio anguillarum is the causative agent of vibriosis, a deadly haemorrhagic septicaemic disease affecting various marine and fresh/brackish water fish, bivalves and crustaceans. However, the diversity and virulence mechanisms of this pathogen are still insufficiently known. In this study, we aimed to increase our understanding of V. anguillarum diversity and virulence through comparative genome analysis of 15 V. anguillarum strains, obtained from different hosts or non-host niches and geographical regions, among which 10 and 5 strains were found to be virulent and avirulent, respectively, against sea bass larvae. First, the 15 draft genomes were annotated and screened for putative virulence factors, including genes encoding iron uptake systems, transport systems and non-ribosomal peptide synthetases. Second, comparative genome analysis was performed, focusing on single nucleotide polymorphisms (SNPs) and small insertions and deletions (InDels). Five V. anguillarum strains showed a remarkably high nucleotide identity. However, these strains comprise both virulent and avirulent strains towards sea bass larvae, suggesting that differences in virulence may be caused by subtle nucleotide variations. Clearly, the draft genome sequence of these 15 strains represents a starting point for further genetic research of this economically important fish pathogen.
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Affiliation(s)
- P Busschaert
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - I Frans
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - S Crauwels
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - B Zhu
- VIB Lab for Systems Biology & Centre of Microbial and Plant Genetics (CMPG), Lab for Genetics and Genomics, M2S, KU Leuven, Leuven, Belgium
| | - K Willems
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - P Bossier
- Laboratory of Aquaculture & Artemia Reference Centre, Department of Animal Production, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - C Michiels
- Centre for Food and Microbial Technology, M2S, KU Leuven, Leuven, Belgium
| | - K Verstrepen
- VIB Lab for Systems Biology & Centre of Microbial and Plant Genetics (CMPG), Lab for Genetics and Genomics, M2S, KU Leuven, Leuven, Belgium
| | - B Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
| | - H Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), KU Leuven - Campus De Nayer, Sint-Katelijne-Waver, Belgium
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15
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A Transmissible Plasmid-Borne Pathogenicity Island Confers Piscibactin Biosynthesis in the Fish Pathogen Photobacterium damselae subsp. piscicida. Appl Environ Microbiol 2015; 81:5867-79. [PMID: 26092457 DOI: 10.1128/aem.01580-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/15/2015] [Indexed: 11/20/2022] Open
Abstract
The fish pathogen Photobacterium damselae subsp. piscicida produces the siderophore piscibactin. A gene cluster that resembles the Yersinia high-pathogenicity island (HPI) encodes piscibactin biosynthesis. Here, we report that this HPI-like cluster is part of a hitherto-uncharacterized 68-kb plasmid dubbed pPHDP70. This plasmid lacks homologs of genes that mediate conjugation, but we found that it could be transferred at low frequencies from P. damselae subsp. piscicida to a mollusk pathogenic Vibrio alginolyticus strain and to other Gram-negative bacteria, likely dependent on the conjugative functions of the coresident plasmid pPHDP60. Following its conjugative transfer, pPHDP70 restored the capacity of a vibrioferrin mutant of V. alginolyticus to grow under low-iron conditions, and piscibactin became detectable in its supernatant. Thus, pPHDP70 appears to harbor all the genes required for piscibactin biosynthesis and transport. P. damselae subsp. piscicida strains cured of pPHDP70 no longer produced piscibactin, had impaired growth under iron-limited conditions, and exhibited markedly decreased virulence in fish. Collectively, our findings highlight the importance of pPHDP70, with its capacity for piscibactin-mediated iron acquisition, in the virulence of P. damselae subsp. piscicida. Horizontal transmission of this plasmid-borne piscibactin synthesis gene cluster in the marine environment may facilitate the emergence of new pathogens.
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Arkoosh MR, Dietrich JP. Pathogenicity of members of the vibrionaceae family to cultured juvenile sablefish. JOURNAL OF AQUATIC ANIMAL HEALTH 2015; 27:96-103. [PMID: 25970236 DOI: 10.1080/08997659.2015.1019159] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Sablefish Anoplopoma fimbria are a prized seafood species due to their high oil content and white flaky flesh. Raising these species in culture can help to provide an important source of protein for humans and relief to declining wild fish populations. Understanding the environmental factors that influence the production of Sablefish is important for successful culturing. The significance of host-pathogen interactions in Sablefish culture and the resulting environmental implications are unknown. Pathogens could potentially cause losses of cultured Sablefish stocks due to disease, while Sablefish cultured in net pens may also serve as reservoirs for pathogens and potentially transmit disease to wild fish species. In this initial study, the susceptibility of juvenile Sablefish to three bacterial pathogens from the family Vibrionaceae was examined. Listonella anguillarum, Vibrio ordalii, and V. splendidus can pose serious economic threats to cultured fish and shellfish. Groups of juvenile Sablefish were exposed to five concentrations of each of the pathogens. Sablefish were susceptible to L. anguillarum, but were resistant to V. ordalii and V. splendidus at exposure concentrations of ≤ 1.32 × 10⁷ CFU/mL and ≤ 3.57 × 10⁶ CFU/mL, respectively. The greatest L. anguillarum concentration examined (8.7 × 10⁶ CFU/mL) resulted in 24% mortality in juvenile Sablefish. A 24% loss of Sablefish stock could significantly influence an aquaculture program. As determined by multiple logistic regression, the survival of Sablefish to L. anguillarum exposure was significantly affected by their body mass, and larger fish had a greater probability of survival. Aquaculture operations could employ various strategies to minimize the loss of juvenile Sablefish by accounting for their size and known susceptibilities to pathogens.
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Affiliation(s)
- Mary R Arkoosh
- a National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northwest Fisheries Science Center , Environmental and Fisheries Sciences Division , 2032 Southeast OSU Drive, Newport , Oregon 97365 , USA
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17
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Abstract
ABSTRACT
Plasmids confer genetic information that benefits the bacterial cells containing them. In pathogenic bacteria, plasmids often harbor virulence determinants that enhance the pathogenicity of the bacterium. The ability to acquire iron in environments where it is limited, for instance the eukaryotic host, is a critical factor for bacterial growth. To acquire iron, bacteria have evolved specific iron uptake mechanisms. These systems are often chromosomally encoded, while those that are plasmid-encoded are rare. Two main plasmid types, ColV and pJM1, have been shown to harbor determinants that increase virulence by providing the cell with essential iron for growth. It is clear that these two plasmid groups evolved independently from each other since they do not share similarities either in the plasmid backbones or in the iron uptake systems they harbor. The siderophores aerobactin and salmochelin that are found on ColV plasmids fall in the hydroxamate and catechol group, respectively, whereas both functional groups are present in the anguibactin siderophore, the only iron uptake system found on pJM1-type plasmids. Besides siderophore-mediated iron uptake, ColV plasmids carry additional genes involved in iron metabolism. These systems include ABC transporters, hemolysins, and a hemoglobin protease. ColV- and pJM1-like plasmids have been shown to confer virulence to their bacterial host, and this trait can be completely ascribed to their encoded iron uptake systems.
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18
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Crisafi F, Denaro R, Genovese M, Yakimov M, Genovese L. Application of relative real-time PCR to detect differential expression of virulence genes in Vibrio anguillarum under standard and stressed growth conditions. JOURNAL OF FISH DISEASES 2014; 37:629-640. [PMID: 24033758 DOI: 10.1111/jfd.12158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 06/27/2013] [Accepted: 06/30/2013] [Indexed: 06/02/2023]
Abstract
In this study, we aimed to understand whether abiotic factors affect the expression of virulence genes in Vibrio anguillarum. We observed the in vitro responses of two Mediterranean strains of V. anguillarum to temperature, NaCl and iron concentration changes. We monitored growth performance and gene transcription levels by comparing the results obtained under stressed conditions (temperatures of 5 °C, 15 °C and 37 °C; NaCl concentrations of 3% and 5%; and iron depletion and excess) with those obtained under standard growth conditions (25 °C, 1.5% NaCl and 0.6 μm of iron). The results showed that the strains respond differently. The strain 975/I was most strongly affected by conditions of 15 °C and iron depletion; these conditions induced increased transcription levels of empA, angR and fatA. Growth of the strain 17/I was inhibited at 15 °C and in iron depletion conditions; this strain also showed dramatic changes in the transcription levels of toxR and tonB2 under increased NaCl concentrations. These results demonstrate that environmental stress affects the expression of virulence genes in V. anguillarum that have implications for the competitiveness, stress tolerance and the ability of V. anguillarum to cause infection.
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Affiliation(s)
- F Crisafi
- Institute for Coastal Marine Environment (IAMC), CNR, Messina, Italy
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19
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Nguyen AN, Jacq A. Small RNAs in the Vibrionaceae: an ocean still to be explored. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:381-92. [PMID: 24458378 DOI: 10.1002/wrna.1218] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 12/13/2013] [Accepted: 12/16/2013] [Indexed: 11/09/2022]
Abstract
In bacteria, the discovery of noncoding small RNAs (sRNAs) as modulators of gene expression in response to environmental signals has brought new insights into bacterial gene regulation, including control of pathogenicity. The Vibrionaceae constitute a family of marine bacteria of which many are responsible for infections affecting not only humans, such as Vibrio cholerae but also fish and marine invertebrates, representing the major cause of mortality in farmed marine species. They are able to colonize many habitats, existing as planktonic forms, in biofilms or associated with various hosts. This high adaptability is linked to their capacity to generate genetic diversity, in part through lateral gene transfer, but also by varying gene expression control. In the recent years, several major studies have illustrated the importance of small regulatory sRNAs in the Vibrionaceae for the control of pathogenicity and adaptation to environment and nutrient sources such as chitin, especially in V. cholerae and Vibrio harveyi. The existence of a complex regulatory network controlled by quorum sensing has been demonstrated in which sRNAs play central roles. This review covers major advances made in the discovery and elucidation of functions of Vibrionaceae sRNAs within the last 10 years.
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Affiliation(s)
- An Ngoc Nguyen
- Institut de Génétique et Microbiologie, UMR 8621 CNRS-Université Paris-Sud, 91405 Orsay Cedex, France
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20
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Li L, Mou X, Nelson DR. Characterization of Plp, a phosphatidylcholine-specific phospholipase and hemolysin of Vibrio anguillarum. BMC Microbiol 2013; 13:271. [PMID: 24279474 PMCID: PMC4222444 DOI: 10.1186/1471-2180-13-271] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 11/20/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vibrio anguillarum is the causative agent of vibriosis in fish. Several extracellular proteins secreted by V. anguillarum have been shown to contribute to virulence. While two hemolysin gene clusters, vah1-plp and rtxACHBDE, have been previously identified and described, the activities of the protein encoded by the plp gene were not known. Here we describe the biochemical activities of the plp-encoded protein and its role in pathogenesis. RESULTS The plp gene, one of the components in vah1 cluster, encodes a 416-amino-acid protein (Plp), which has homology to lipolytic enzymes containing the catalytic site amino acid signature SGNH. Hemolytic activity of the plp mutant increased 2-3-fold on sheep blood agar indicating that plp represses vah1; however, hemolytic activity of the plp mutant decreased by 2-3-fold on fish blood agar suggesting that Plp has different effects against erythrocytes from different species. His6-tagged recombinant Plp protein (rPlp) was over-expressed in E. coli. Purified and re-folded active rPlp exhibited phospholipase A2 activity against phosphatidylcholine and no activity against phosphatidylserine, phosphatidylethanolamine, or sphingomyelin. Characterization of rPlp revealed broad optimal activities at pH 5-9 and at temperatures of 30-64°C. Divalent cations and metal chelators did not affect activity of rPlp. We also demonstrated that Plp was secreted using thin layer chromatography and immunoblot analysis. Additionally, rPlp had strong hemolytic activity towards rainbow trout erythrocytes, but not to sheep erythrocytes suggesting that rPlp is optimized for lysis of phosphatidylcholine-rich fish erythrocytes. Further, only the loss of the plp gene had a significant effect on hemolytic activity of culture supernatant on fish erythrocytes, while the loss of rtxA and/or vah1 had little effect. However, V. anguillarum strains with mutations in plp or in plp and vah1 exhibited no significant reduction in virulence compared to the wild type strain when used to infect rainbow trout. CONCLUSION The plp gene of V. anguillarum encoding a phospholipase with A2 activity is specific for phosphatidylcholine and, therefore, able to lyse fish erythrocytes, but not sheep erythrocytes. Mutation of plp does not affect the virulence of V. anguillarum in rainbow trout.
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Affiliation(s)
- Ling Li
- Department of Cell and Molecular Biology, University of Rhode Island, 120 Flagg Rd,, Kingston, RI 02881, USA.
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Plasmid- and chromosome-encoded siderophore anguibactin systems found in marine vibrios: biosynthesis, transport and evolution. Biometals 2013; 26:537-47. [PMID: 23660776 DOI: 10.1007/s10534-013-9629-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/28/2013] [Indexed: 01/04/2023]
Abstract
Vibrio anguillarum is a marine pathogen that causes vibriosis, a hemorrhagic septicemia in aquatic invertebrate as well as vertebrate animals. The siderophore anguibactin system is one of the most important virulence factors of this bacterium. Most of the anguibactin biosynthesis and transport genes are located in the 65-kb pJM1 virulence plasmid although some of them are found in the chromosome of this fish pathogen. Over 30 years of research unveiled the role numerous chromosomal and pJM1 genes play in the synthesis of anguibactin and the transport of cognate ferric complexes into the bacterial cell. Furthermore, these studies showed that pJM1-carrying strains might be originated from pJM1-less strains producing the chromosome-mediated siderophore vanchrobactin. Additionally, we recently identified a chromosome-mediated anguibactin system in V. harveyi suggesting the possible evolutional origin of the V. anguillarum anguibactin system. In this review, we present our current understanding of the mechanisms and evolution hypothesis of the anguibactin system that might have occurred in these pathogenic vibrios.
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Development of TaqMan real-time PCR assays for monitoring Vibrio harveyi infection and a plasmid harbored by virulent strains in European abalone Haliotis tuberculata aquaculture. AQUACULTURE 2013. [DOI: 10.1016/j.aquaculture.2013.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Naka H, Liu M, Crosa JH. Two ABC transporter systems participate in siderophore transport in the marine pathogen Vibrio anguillarum 775 (pJM1). FEMS Microbiol Lett 2013; 341:79-86. [PMID: 23350649 DOI: 10.1111/1574-6968.12092] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 12/25/2012] [Accepted: 01/22/2013] [Indexed: 11/30/2022] Open
Abstract
ORF40 (named fatE) in the Vibrio anguillarum pJM1 plasmid-encoding anguibactin iron transport systems is a homolog of ATPase genes involved in ferric-siderophore transport. Mutation of fatE did not affect ferric-anguibactin transport, indicating that there must be other ATPase gene(s) in addition to fatE. By searching the genomic sequence of V. anguillarum 775(pJM1), we identified a homolog of fatE named fvtE on chromosome 2. It is of interest that in this locus, we also identified homologs of fatB, fatC, and fatD that we named fvtB, fvtC and fvtD, respectively. The fvtE mutant still showed ferric-anguibactin transport, while the double fatE and fvtE mutation completely abolished the ferric-anguibactin transport indicating that fatE and fvtE are functional ATPase homologs for ferric-anguibactin transport. Furthermore, we demonstrate that fvtB, fvtC, fvtD, and fvtE are essential for ferric-vanchrobactin and ferric-enterobactin transport.
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Affiliation(s)
- Hiroaki Naka
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA.
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Naka H, Actis LA, Crosa JH. The anguibactin biosynthesis and transport genes are encoded in the chromosome of Vibrio harveyi: a possible evolutionary origin for the pJM1 plasmid-encoded system of Vibrio anguillarum? Microbiologyopen 2013; 2:182-94. [PMID: 23335587 PMCID: PMC3584223 DOI: 10.1002/mbo3.65] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 11/22/2012] [Accepted: 12/03/2012] [Indexed: 12/31/2022] Open
Abstract
Many Vibrio anguillarum serotype O1 strains carry 65-kb pJM1-type plasmids harboring genes involved in siderophore anguibactin biosynthesis and transport. The anguibactin system is an essential factor for V. anguillarum to survive under iron-limiting conditions, and as a consequence, it is a very important virulence factor of this bacterium. Our comparative analysis of genomic data identified a cluster harboring homologs of anguibactin biosynthesis and transport genes in the chromosome of Vibrio harveyi. We have purified the putative anguibactin siderophore and demonstrated that it is indeed anguibactin by mass spectrometry and specific bioassays. Furthermore, we characterized two genes, angR and fatA, in this chromosome cluster that, respectively, participate in anguibactin biosynthesis and transport as determined by mutagenesis analysis. Furthermore, we found that the V. harveyi FatA protein is located in the outer membrane fractions as previously demonstrated in V. anguillarum. Based on our data, we propose that the anguibactin biosynthesis and transport cluster in the V. anguillarum pJM1 plasmid have likely evolved from the chromosome cluster of V. harveyi or vice versa.
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Affiliation(s)
- Hiroaki Naka
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, USA.
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25
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Penwell WF, Arivett BA, Actis LA. The Acinetobacter baumannii entA gene located outside the acinetobactin cluster is critical for siderophore production, iron acquisition and virulence. PLoS One 2012; 7:e36493. [PMID: 22570720 PMCID: PMC3343012 DOI: 10.1371/journal.pone.0036493] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 04/09/2012] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii causes severe infections in compromised patients, who present an iron-limited environment that controls bacterial growth. This pathogen has responded to this restriction by expressing high-affinity iron acquisition systems including that mediated by the siderophore acinetobactin. Gene cloning, functional assays and biochemical tests showed that the A. baumannii genome contains a single functional copy of an entA ortholog. This gene, which is essential for the biosynthesis of the acinetobactin precursor 2,3-dihydroxybenzoic acid (DHBA), locates outside of the acinetobactin gene cluster, which otherwise harbors all genes needed for acinetobactin biosynthesis, export and transport. In silico analyses and genetic complementation tests showed that entA locates next to an entB ortholog, which codes for a putative protein that contains the isochorismatase lyase domain, which is needed for DHBA biosynthesis from isochorismic acid, but lacks the aryl carrier protein domain, which is needed for tethering activated DHBA and completion of siderophore biosynthesis. Thus, basF, which locates within the acinetobactin gene cluster, is the only fully functional entB ortholog present in ATCC 19606(T). The differences in amino acid length and sequences between these two EntB orthologs and the differences in the genetic context within which the entA and entB genes are found in different A. baumannii isolates indicate that they were acquired from different sources by horizontal transfer. Interestingly, the AYE strain proved to be a natural entA mutant capable of acquiring iron via an uncharacterized siderophore-mediated system, an observation that underlines the ability of different A. baumannii isolates to acquire iron using different systems. Finally, experimental infections using in vivo and ex vivo models demonstrate the role of DHBA and acinetobactin intermediates in the virulence of the ATCC 19606(T) cells, although to a lesser extent when compared to the responses obtained with bacteria producing and using fully matured acinetobactin to acquire iron.
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Affiliation(s)
- William F. Penwell
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Brock A. Arivett
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Luis A. Actis
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
- * E-mail:
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Genome sequence of the marine bacterium Vibrio campbellii DS40M4, isolated from open ocean water. J Bacteriol 2012; 194:904. [PMID: 22275102 DOI: 10.1128/jb.06583-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Vibrio sp. strain DS40M4 is a marine bacterium that was isolated from open ocean water. In this work, using genomic taxonomy, we were able to classify this bacterium as V. campbellii. Our genomic analysis revealed that V. campbellii DS40M4 harbors genes related to iron transport, virulence, and environmental fitness, such as those encoding anguibactin and vanchrobactin biosynthesis proteins, type II, III, IV, and VI secretion systems, and proteorhodopsin.
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Macpherson HL, Bergh Ø, Birkbeck TH. An aerolysin-like enterotoxin from Vibrio splendidus may be involved in intestinal tract damage and mortalities in turbot, Scophthalmus maximus (L.), and cod, Gadus morhua L., larvae. JOURNAL OF FISH DISEASES 2012; 35:153-167. [PMID: 22233514 DOI: 10.1111/j.1365-2761.2011.01331.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Vibrio splendidus is a pathogen that can cause major losses during the early stages of larval turbot rearing when live feed (rotifers or Artemia) is used. As haemolytic bacteria have often been associated with larval rearing losses, we studied the role of the V. splendidus haemolysin in infection of larvae. From a bank of over 10,000 transposon mutants of V. splendidus, two different types of haemolysin-negative mutants were obtained. Both had lost virulence for larval fish, and immunohistochemistry showed that the transposon mutant studied colonized the turbot larval intestinal tract at a similar level to the wild-type organism but did not cause damage or signs of enteritis found with the wild-type organism. One transposon insertion site was located within a gene with high homology to aerolysin, the cytolytic toxin produced by several Aeromonas spp. The haemolysin, which we have termed vibrioaerolysin, had properties similar to aerolysin and osmotic protection studies showed that it formed pores in the membranes of erythrocytes of similar diameter to those of aerolysin. The Tn10 insertion site of the second transposon mutant was in an adjacent ToxR-like gene, suggesting that this might control expression of the vibrioaerolysin. The gastroenteritis caused by Aeromonas spp. in humans is considered to be due to production of aerolysin causing cyclic AMP-dependent chloride secretion in cells of the gastrointestinal tract. Damage to the intestinal tract of marine fish larvae could occur in a similar way, and it is possible that several Vibrio spp. found in the developing bacterial flora of the larval fish gut can secrete aerolysin-like toxins leading to death of larvae in the early rearing stages. Routine bacteriological screening on blood agar plates of live feed is recommended with measures to reduce the concentrations of haemolytic bacteria in rearing systems.
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Affiliation(s)
- H L Macpherson
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
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Two replication regions in the pJM1 virulence plasmid of the marine pathogen Vibrio anguillarum. Plasmid 2012; 67:95-101. [PMID: 22239981 DOI: 10.1016/j.plasmid.2011.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 11/24/2022]
Abstract
Vibrio anguillarum is a fish pathogen that causes vibriosis, a serious hemorrhagic septicemia, in wild and cultured fish. Many serotype O1 strains of this bacterium harbor the 65kb plasmid pJM1 carrying the majority of genes encoding the siderophore anguibactin iron transport system that is one of the most important virulence factors of this bacterium. We previously identified a replication region of the pJM1 plasmid named ori1. In this work we determined that ori1 can replicate in Escherichia coli and that the chromosome-encoded proteins DnaB, DnaC and DnaG are essential for its replication whereas PolI, IHF and DnaA are not required. The copy number of the pJM1 plasmid is 1-2, albeit cloned smaller fragments of the ori1 region replicate with higher copy numbers in V. anguillarum while in E. coli we did not observe an obvious difference of the copy numbers of these constructs which were all high. Furthermore, we were able to delete the ori1 region from the pJM1 plasmid and identified a second replication region in pJM1 that we named ori2. This second replication region is located on ORF25 that is within the trans-acting factor (TAFr) region, and showed that it can only replicate in V. anguillarum.
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Frans I, Michiels CW, Bossier P, Willems KA, Lievens B, Rediers H. Vibrio anguillarum as a fish pathogen: virulence factors, diagnosis and prevention. JOURNAL OF FISH DISEASES 2011; 34:643-661. [PMID: 21838709 DOI: 10.1111/j.1365-2761.2011.01279.x] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Vibrio anguillarum, also known as Listonella anguillarum, is the causative agent of vibriosis, a deadly haemorrhagic septicaemic disease affecting various marine and fresh/brackish water fish, bivalves and crustaceans. In both aquaculture and larviculture, this disease is responsible for severe economic losses worldwide. Because of its high morbidity and mortality rates, substantial research has been carried out to elucidate the virulence mechanisms of this pathogen and to develop rapid detection techniques and effective disease-prevention strategies. This review summarizes the current state of knowledge pertaining to V. anguillarum, focusing on pathogenesis, known virulence factors, diagnosis, prevention and treatment.
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Affiliation(s)
- I Frans
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Consortium for Industrial Microbiology and Biotechnology, Department of Microbial and Molecular Systems, K.U. Leuven Association, Lessius Mechelen, Sint-Katelijne-Waver, Belgium
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The Photobacterium damselae subsp. damselae hemolysins damselysin and HlyA are encoded within a new virulence plasmid. Infect Immun 2011; 79:4617-27. [PMID: 21875966 DOI: 10.1128/iai.05436-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Photobacterium damselae subsp. damselae (formerly Vibrio damsela) is a marine bacterium that causes infections and fatal disease in a wide range of marine animals and in humans. Highly hemolytic strains produce damselysin (Dly), a cytolysin encoded by the dly gene that is lethal for mice and has hemolytic activity. We found that Dly is encoded in the highly hemolytic strain RM-71 within a 153,429-bp conjugative plasmid that we dubbed pPHDD1. In addition to Dly, pPHDD1 also encodes a homologue of the pore-forming toxin HlyA. We found a direct correlation between presence of pPHDD1 and a strong hemolytic phenotype in a collection of P. damselae subsp. damselae isolates. Hemolysis was strongly reduced in a double dly hlyA mutant, demonstrating the role of the two pPHDD1-encoded genes in hemolysis. Interestingly, although single hlyA and dly mutants showed different levels of hemolysis reduction depending on the erythrocyte source, hemolysis was not abolished in any of the single mutants, suggesting that the hemolytic phenotype is the result of the additive effect of Dly and HlyA. We found that pPHDD1-encoded dly and hlyA genes are necessary for full virulence for mice and fish. Our results suggest that pPHDD1 can be considered as a driving force for the emergence of a highly hemolytic lineage of P. damselae subsp. damselae.
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Identification and characterization of a novel outer membrane protein receptor FetA for ferric enterobactin transport in Vibrio anguillarum 775 (pJM1). Biometals 2011; 25:125-33. [PMID: 21842211 DOI: 10.1007/s10534-011-9488-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 08/03/2011] [Indexed: 10/17/2022]
Abstract
In this work we demonstrate the existence in Vibrio anguillarum 775 (pJM1) of two chromosomal genes encoding outer membrane proteins that operate in the transport of ferric enterobactin. One of them is a novel receptor that we named FetA and the other is the already characterized FvtA that functions in the uptake of iron complexes of both enterobactin and vanchrobactin. Ferric enterobactin transport proficiency was resumed in double mutants for these two genes when they were complemented with either fetA or fvtA, whereas only the cloned fvtA could complement for ferric vanchrobactin transport. Quantitative RT-PCR assays demonstrated that transcription of the fetA gene is regulated by FetR, that is encoded upstream and in reverse orientation from fetA. This gene as well as fetA, are up-regulated in iron limiting condition in a Fur-dependent manner. The two divergent promoters are located in the intergenic region between fetR and fetA that has a putative Fur binding site and an IrgB binding site in the overlapping promoters of fetR and fetA. FetA and FetR show high homology to V. cholerae IrgA and IrgB respectively and the intergenic regions fetA-fetR and irgA-irgB are also highly related suggesting a vertical transmission of the fetA-fetR cluster from V. cholerae to V. anguillarum.
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Complete genome sequence of the marine fish pathogen Vibrio anguillarum harboring the pJM1 virulence plasmid and genomic comparison with other virulent strains of V. anguillarum and V. ordalii. Infect Immun 2011; 79:2889-900. [PMID: 21576332 DOI: 10.1128/iai.05138-11] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We dissected the complete genome sequence of the O1 serotype strain Vibrio anguillarum 775(pJM1) and determined the draft genomic sequences of plasmidless strains of serotype O1 (strain 96F) and O2β (strain RV22) and V. ordalii. All strains harbor two chromosomes, but 775 also harbors the virulence plasmid pJM1, which carries the anguibactin-producing and cognate transport genes, one of the main virulence factors of V. anguillarum. Genomic analysis identified eight genomic islands in chromosome 1 of V. anguillarum 775(pJM1) and two in chromosome 2. Some of them carried potential virulence genes for the biosynthesis of O antigens, hemolysins, and exonucleases as well as others for sugar transport and metabolism. The majority of genes for essential cell functions and pathogenicity are located on chromosome 1. In contrast, chromosome 2 contains a larger fraction (59%) of hypothetical genes than does chromosome 1 (42%). Chromosome 2 also harbors a superintegron, as well as host "addiction" genes that are typically found on plasmids. Unique distinctive properties include homologues of type III secretion system genes in 96F, homologues of V. cholerae zot and ace toxin genes in RV22, and the biofilm formation syp genes in V. ordalii. Mobile genetic elements, some of them possibly originated in the pJM1 plasmid, were very abundant in 775, resulting in the silencing of specific genes, with only few insertions in the 96F and RV22 chromosomes.
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Hazen TH, Pan L, Gu JD, Sobecky PA. The contribution of mobile genetic elements to the evolution and ecology of Vibrios. FEMS Microbiol Ecol 2011; 74:485-99. [PMID: 20662928 DOI: 10.1111/j.1574-6941.2010.00937.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
An increase in the frequency of seafood-borne gastroenteritis in humans and Vibrio-related disease of fish and invertebrates has generated interest in the ecology of disease-causing Vibrios and the mechanisms driving their evolution. Genome sequencing studies have indicated a substantial contribution of horizontal gene transfer (HGT) to the evolution of Vibrios. Of particular interest is the contribution of HGT to the evolution of Vibrios pathogens and the adaptation of disease-causing Vibrios for survival in diverse environments. In this review, we discuss the diversity and distribution of mobile genetic elements (MGEs) isolated from Vibrios and the contribution of these elements to the expansion of the ecological and pathogenic niches of the host strain. Much of the research on Vibrio MGEs has focused on understanding phages and plasmids and we will primarily discuss the evolution of these elements and also briefly highlight the other diverse elements characterized from Vibrios, which includes genomic islands and conjugative elements.
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Affiliation(s)
- Tracy H Hazen
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
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Erauso G, Lakhal F, Bidault-Toffin A, Le Chevalier P, Bouloc P, Paillard C, Jacq A. Evidence for the role of horizontal transfer in generating pVT1, a large mosaic conjugative plasmid from the clam pathogen, Vibrio tapetis. PLoS One 2011; 6:e16759. [PMID: 21326607 PMCID: PMC3033894 DOI: 10.1371/journal.pone.0016759] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 12/29/2010] [Indexed: 02/05/2023] Open
Abstract
The marine bacterium Vibrio tapetis is the causative agent of the brown ring disease, which affects the clam Ruditapes philippinarum and causes heavy economic losses in North of Europe and in Eastern Asia. Further characterization of V. tapetis isolates showed that all the investigated strains harbored at least one large plasmid. We determined the sequence of the 82,266 bp plasmid pVT1 from the CECT4600(T) reference strain and analyzed its genetic content. pVT1 is a mosaic plasmid closely related to several conjugative plasmids isolated from Vibrio vulnificus strains and was shown to be itself conjugative in Vibrios. In addition, it contains DNA regions that have similarity with several other plasmids from marine bacteria (Vibrio sp., Shewanella sp., Listonella anguillarum and Photobacterium profundum). pVT1 contains a number of mobile elements, including twelve Insertion Sequences or inactivated IS genes and an RS1 phage element related to the CTXphi phage of V. cholerae. The genetic organization of pVT1 underscores an important role of horizontal gene transfer through conjugative plasmid shuffling and transposition events in the acquisition of new genetic resources and in generating the pVT1 modular organization. In addition, pVT1 presents a copy number of 9, relatively high for a conjugative plasmid, and appears to belong to a new type of replicon, which may be specific to Vibrionaceae and Shewanelleacae.
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Affiliation(s)
- Gaël Erauso
- Laboratoire des Sciences de l'Environnement Marin, UMR 6539, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, CNRS, Plouzané, France
| | - Fatma Lakhal
- Institut de Génétique et Microbiologie, UMR 8621, Université Paris-Sud 11, CNRS, IFR115, Orsay, France
| | - Adeline Bidault-Toffin
- Laboratoire des Sciences de l'Environnement Marin, UMR 6539, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, CNRS, Plouzané, France
| | - Patrick Le Chevalier
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, Université de Bretagne Occidentale, Quimper, France
| | - Philippe Bouloc
- Institut de Génétique et Microbiologie, UMR 8621, Université Paris-Sud 11, CNRS, IFR115, Orsay, France
| | - Christine Paillard
- Laboratoire des Sciences de l'Environnement Marin, UMR 6539, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, CNRS, Plouzané, France
| | - Annick Jacq
- Institut de Génétique et Microbiologie, UMR 8621, Université Paris-Sud 11, CNRS, IFR115, Orsay, France
- * E-mail:
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Di Lorenzo M, Stork M, Crosa JH. Genetic and biochemical analyses of chromosome and plasmid gene homologues encoding ICL and ArCP domains in Vibrio anguillarum strain 775. Biometals 2011; 24:629-43. [PMID: 21286786 PMCID: PMC3123441 DOI: 10.1007/s10534-011-9416-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 01/10/2011] [Indexed: 11/30/2022]
Abstract
Anguibactin, the siderophore produced by Vibrioanguillarum 775 is synthesized from 2,3-dihydroxybenzoic acid (DHBA), cysteine and hydroxyhistamine via a nonribosomal peptide synthetase (NRPS) mechanism. Most of the genes encoding anguibactin biosynthetic proteins are harbored by the pJM1 plasmid. In this work we report the identification of a homologue of the plasmid-encoded angB on the chromosome of strain 775. The product of both genes harbor an isochorismate lyase (ICL) domain that converts isochorismic acid to 2,3-dihydro-2,3-dihydroxybenzoic acid, one of the steps of DHBA synthesis. We show in this work that both ICL domains are functional in the production of DHBA in V. anguillarum as well as in E. coli. Substitution by alanine of the aspartic acid residue in the active site of both ICL domains completely abolishes their isochorismate lyase activity in vivo. The two proteins also carry an aryl carrier protein (ArCP) domain. In contrast with the ICL domains only the plasmid encoded ArCP can participate in anguibactin production as determined by complementation analyses and site-directed mutagenesis in the active site of the plasmid encoded protein, S248A. The site-directed mutants, D37A in the ICL domain and S248A in the ArCP domain of the plasmid encoded AngB were also tested in vitro and clearly show the importance of each residue for the domain function and that each domain operates independently.
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Affiliation(s)
- Manuela Di Lorenzo
- Department of Microbial Ecology, Netherlands Institute of Ecology, Wageninegen, The Netherlands.
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Naka H, Crosa JH. Genetic Determinants of Virulence in the Marine Fish Pathogen Vibrio anguillarum. FISH PATHOLOGY 2011; 46:1-10. [PMID: 21625345 PMCID: PMC3103123 DOI: 10.3147/jsfp.46.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
One of the most studied fish pathogens is Vibrio anguillarum. Development of the genetics and biochemistry of the mechanisms of virulence in this fish pathogen together with clinical and ecologic studies has permitted the intensive development of microbiology in fish diseases. It is the intention of this review to compile the exhaustive knowledge accumulated on this bacterium and its interaction with the host fish by reporting a complete analysis of the V. anguillarum virulence factors and the genetics of their complexity.
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Zou YX, Mo ZL, Hao B, Ye XH, Guo DS, Zhang PJ. Screening of genes expressed in vivo after infection by Vibrio anguillarum M3. Lett Appl Microbiol 2010; 51:564-9. [PMID: 20849396 DOI: 10.1111/j.1472-765x.2010.02935.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Genes uniquely expressed in vivo may contribute to the overall pathogenicity of an organism and are likely to serve as potential targets for the development of new vaccine. This study aims to screen the genes expressed in vivo after Vibrio anguillarum infection by in vivo-induced antigen technology (IVIAT). METHODS AND RESULTS The convalescent-phase sera were obtained from turbot (Scophthalmus maximus) survived after infection by the virulent V. anguillarum M3. The pooled sera were thoroughly adsorbed with M3 cells and Escherichia coli BL21 (DE3) cells. A genomic expression library of M3 was constructed and screened for the identification of immunogenic proteins by colony immunoblot analysis with the adsorbed sera. After three rounds of screening, 19 putative in vivo-induced (ivi) genes were obtained. These ivi genes were catalogued into four functional groups: regulator/signalling, metabolism, biological process and hypothetical proteins. Three ivi genes were insertion-mutated, and the growth and 50% lethal dose (LD(50) ) of these mutants were evaluated. CONCLUSIONS The identification of ivi genes in V. anguillarum M3 sheds light on understanding the bacterial pathogenesis and provides novel targets for the development of new vaccines and diagnostic reagents. SIGNIFICANCE AND IMPACT OF THE STUDY To the best of our knowledge, this is the first report describing in vivo-expressed genes of V. anguillarum using IVIAT. The screened ivi genes in this study could be new virulent factors and targets for the development of vaccine, which may have implications for the development of diagnostic regents.
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Affiliation(s)
- Y-X Zou
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
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Björnsdóttir-Butler K, Bolton GE, Jaykus LA, McClellan-Green PD, Green DP. Development of molecular-based methods for determination of high histamine producing bacteria in fish. Int J Food Microbiol 2010; 139:161-7. [DOI: 10.1016/j.ijfoodmicro.2010.03.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 03/08/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
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Lemos ML, Balado M, Osorio CR. Anguibactin- versus vanchrobactin-mediated iron uptake in Vibrio anguillarum: evolution and ecology of a fish pathogen. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:19-26. [PMID: 23765994 DOI: 10.1111/j.1758-2229.2009.00103.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vibrio anguillarum is a marine bacterium that is present in many marine aquatic environments and that is the main cause of vibriosis in diverse wild and cultured fish species. Two siderophore-mediated iron uptake systems have been described in V. anguillarum. One, mediated by the siderophore anguibactin, is encoded by the pJM1-type plasmids and is restricted to serotype O1 strains. The second one is mediated by the vanchrobactin siderophore and is widespread in many strains belonging to different serotypes. Both siderophores belong to the catecholate group of siderophores, sharing a 2,3-dihydroxybenzoic acid moiety. Vanchrobactin biosynthesis and transport genes are present in all strains examined although the siderophore is not produced in serotype O1 strains harbouring a pJM1-type plasmid. In these strains the insertion of an IS element in the main vanchrobactin biosynthetic gene vabF leads to the fact that only anguibactin is produced. From our current knowledge we can presume that vanchrobactin is the ancestral siderophore in this species and that the anguibactin-mediated system was later acquired during evolution, likely by horizontal transfer. The role of these two different iron uptake mechanisms in the biology, evolution and ecology of V. anguillarum is discussed although they are still far from being completely understood.
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Affiliation(s)
- Manuel L Lemos
- Department of Microbiology and Parasitology, Institute of Aquaculture, University of Santiago de Compostela, Campus Sur, Santiago de Compostela 15782, Spain
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Naka H, López CS, Crosa JH. Role of the pJM1 plasmid-encoded transport proteins FatB, C and D in ferric anguibactin uptake in the fish pathogen Vibrio anguillarum. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:104-111. [PMID: 21304833 PMCID: PMC3034151 DOI: 10.1111/j.1758-2229.2009.00110.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Vibrio anguillarum serotype O1 is part of the natural flora in the aquatic habitat, but under certain circumstances it can cause terminal haemorrhagic septicemia in marine and fresh water fish due to the action of the anguibactin iron uptake system encoded by the virulence plasmid pJM1. This plasmid harbours the genes for the biosynthesis of the siderophore anguibactin and the ferric anguibactin transport proteins FatD, C, B and A encoded in the iron transport operon. The FatA protein is the outer membrane receptor for the ferric siderophore complex and the FatB lipoprotein provides the periplasmic domain for its internalization, whereas the FatC and D proteins are located in the cytoplasmic membrane and might play a role as part of the ABC transporter for internalization of the ferric siderophore. In this work we demonstrate the essential role of these two inner membrane proteins in ferric anguibactin transport and that the lipo-protein nature of FatB is not necessary for ferric anguibactin transport.
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Affiliation(s)
| | | | - Jorge H. Crosa
- For correspondence. ; Tel. (+1) 503 494 7583; Fax (+1) 503 494 6862
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Bjornsdottir K, Bolton GE, McClellan-Green PD, Jaykus LA, Green DP. Detection of gram-negative histamine-producing bacteria in fish: a comparative study. J Food Prot 2009; 72:1987-91. [PMID: 19777904 DOI: 10.4315/0362-028x-72.9.1987] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Poisoning due to ingestion of foods with elevated levels of biogenic amines (histamine, putrescine, cadaverine, and tyramine) is well documented. Histamine fish poisoning largely is due to growth of naturally occurring bacteria associated with scombroid fish species. A rapid and reliable method is needed to screen for the presence of histamine-forming bacteria in fish. This study included a comparison of three methods for the detection of histamine-producing bacteria. A total of 152 histamine-producing and non-histamine-producing bacteria from multiple sources were screened using a modified Niven's agar method, a potentiometric method, and a PCR-based assay targeting a 709-bp fragment of the histidine decarboxylase gene. Histamine production by bacterial isolates was confirmed by high-performance liquid chromatography (HPLC). Bacterial strains were categorized as producing high amounts of histamine, low amounts of histamine, or no histamine. Of the 152 strains tested, 128 (84%) were positive with the Niven's agar method, 73 (48%) were positive with the potentiometric technique, and 74 (49%) were positive with the PCR assay. Overall, a 38% false-positive rate was observed with the modified Niven's agar method, although this method detected both low-histamine and high-histamine strains. There was a high degree of concordance (> 99%) between results of the potentiometric and PCR methods, but neither of these methods detected low-histamine bacteria. These observations support the need for a simple and straightforward yet sensitive method for detecting histamine-producing bacteria in seafood and environmental samples.
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Affiliation(s)
- Kristin Bjornsdottir
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, c/o Center for Marine Sciences and Technology, 303 College Circle, Morehead City, North Carolina 28557, USA
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Castañeda-Carrión IN, Whiteley M, Krumholz LR. Characterization of pNC1, a small and mobilizable plasmid for use in genetic manipulation of Desulfovibrio africanus. J Microbiol Methods 2009; 79:23-31. [PMID: 19631701 DOI: 10.1016/j.mimet.2009.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/13/2009] [Accepted: 07/14/2009] [Indexed: 10/20/2022]
Abstract
To develop a vector system that facilitates genetic manipulation in Desulfovibrio species, we screened native sulfate-reducing bacteria for small plasmids. A self-replicating plasmid was discovered in Desulfovibrio africanus SR-1. Sequence analysis of this 8568-bp plasmid (pNC1) revealed a G+C content of 47.2% and nine open reading frames. This plasmid has a copy number of six. Compatible hosts include D. africanus and Pseudomonas aeruginosa PA14. Genetic characterization of pNC1 revealed that 53.6% of the plasmid contains genes associated with replication, mobilization, and partitioning. The 1123-bp replicon is composed of a rep gene and four 22-bp iterons. The mobilization operon is composed of three genes with a putative 144-bp oriT. The partitioning operon is composed of parA and parB with a downstream parS. We report the construction of a small pNC1-based cloning vector which transforms D. africanus at high frequencies (approximately 1.5 x 10(3) CFU/microg DNA), is mobilizable at high transfer frequency (4.8 x 10(-4) transconjugants/donor), and is stably maintained under non-selective pressure. This study provides a potential host-vector system for Desulfovibrio gene functional analyses.
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Zhang R, Gu JD. Complete sequence of plasmid pMP1 from the marine environmental Vibrio vulnificus and location of its replication origin. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2009; 11:456-462. [PMID: 19009320 DOI: 10.1007/s10126-008-9160-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Accepted: 10/22/2008] [Indexed: 05/27/2023]
Abstract
A novel cryptic plasmid, pMP1, from an environmental Vibrio vulnificus MP-4 isolated from Mai Po Nature Reserve in Hong Kong, has been characterized. The 7.6-kb plasmid had guanine-cytosine content of 40.03% and encoded four open reading frames (ORFs) with >100 amino acids. The predicted protein of ORF1 contained 478 amino acids showing 29% identity and 50% similarity over 309 amino acids to the integrase of Vibrio cholerae phage VP2. ORF2 encoded a putative protein of 596 amino acids, which were 23% identity and 42% similarity over 455 amino acids to the tail tape measure protein TP901 of Chromohalobacter salexigens phage. ORF3 and ORF4 encoded putative proteins of 103 and 287 amino acids, respectively, but showed no homologies to any known proteins. Further experiments indicated that a 3.2-kb fragment from EcoRI digestion could self-replicate. Analysis indicated that a sequence upstream of ORF4 had the features characteristic of theta-type replicons: AT-rich region, six potential direct repeats (iterons) spaced approximately two DNA helical turn apart (about 23 bp), two copies of 9 bp dnaA boxes, three Dam methylation sites, and five inverted repeats. Complementation experiments confirmed that the protein encoded by ORF4 was required for plasmid replication. We propose that ORF4 encode a new type of Rep protein and pMP1 is a new type of theta plasmid.
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Affiliation(s)
- Ruifu Zhang
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, People's Republic of China
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FvtA is the receptor for the siderophore vanchrobactin in Vibrio anguillarum: utility as a route of entry for vanchrobactin analogues. Appl Environ Microbiol 2009; 75:2775-83. [PMID: 19270115 DOI: 10.1128/aem.02897-08] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Some strains of Vibrio anguillarum, the causative agent of vibriosis in a variety of marine animals, produce a catechol-type siderophore named vanchrobactin. The biosynthetic pathway and regulation of vanchrobactin are quite well understood. However, aspects concerning its entry into the cell have remained uncharacterized. In the present study we characterized two genes, fvtA and orf13, encoding potential TonB-dependent ferric-vanchrobactin receptors in serotype O2 V. anguillarum strain RV22. We found that an fvtA mutant was defective for growth under iron limitation conditions and for utilization of vanchrobactin, suggesting that fvtA encodes the vanchrobactin receptor of V. anguillarum. Interestingly, an orf13 mutant was not significantly affected, and results of reverse transcriptase PCR, as well as analysis of outer membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggested that this gene is not expressed. Furthermore, fatA, a plasmid gene coding for the anguibactin receptor in plasmid pJM1-harboring strains, is also present in the chromosome of RV22, although it is inactivated by insertion of transposases. In addition, we found that FvtA is the route of entry for vanchrobactin analogues, and there is evidence that it recognizes primarily the catechol-iron center. These analogues are potential candidate vectors for a Trojan horse strategy aimed at generating antimicrobial compounds exploiting the same route of entry for native siderophores. We found that fvtA and vanchrobactin biosynthesis genes are ubiquitous in both vanchrobactin- and anguibactin-producing V. anguillarum strains, which reinforces the utility of the vanchrobactin route of entry for the design of future strategies for the control of vibriosis.
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Zimbler DL, Penwell WF, Gaddy JA, Menke SM, Tomaras AP, Connerly PL, Actis LA. Iron acquisition functions expressed by the human pathogen Acinetobacter baumannii. Biometals 2009; 22:23-32. [PMID: 19130255 DOI: 10.1007/s10534-008-9202-3] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Accepted: 12/07/2008] [Indexed: 11/26/2022]
Abstract
Acinetobacter baumannii is a gram-negative bacterium that causes serious infections in compromised patients. More recently, it has emerged as the causative agent of severe infections in military personnel wounded in Iraq and Afghanistan. This pathogen grows under a wide range of conditions including iron-limiting conditions imposed by natural and synthetic iron chelators. Initial studies using the type strain 19606 showed that the iron proficiency of this pathogen depends on the expression of the acinetobactin-mediated iron acquisition system. More recently, we have observed that hemin but not human hemoglobin serves as an iron source when 19606 isogenic derivatives affected in acinetobactin transport and biosynthesis were cultured under iron-limiting conditions. This finding is in agreement with the observation that the genome of the strain 17978 has a gene cluster coding for putative hemin-acquisition functions, which include genes coding for putative hemin utilization functions and a TonBExbBD energy transducing system. This system restored enterobactin biosynthesis in an E. coli ExbBD deficient strain but not when introduced into a TonB mutant. PCR and Southern blot analyses showed that this hemin-utilization gene cluster is also present in the 19606 strain. Analysis of the 17978 genome also showed that this strain harbors genes required for acinetobactin synthesis and transport as well as a gene cluster that could code for additional iron acquisition functions. This hypothesis is in agreement with the fact that the inactivation of the basD acinetobactin biosynthetic gene did not affect the growth of A. baumannii 17978 cells under iron-chelated conditions. Interestingly, this second iron uptake gene cluster is flanked by perfect inverted repeats and includes transposase genes that are expressed transcriptionally. Also interesting is the observation that this additional cluster could not be detected in the type strain 19606, an observation that suggests some significant differences in the iron uptake capacity between these two A. baumannii strains. Transposome mutagenesis of the strain 19606 resulted in the isolation of a derivative unable to grow under iron-chelated conditions. Gene mapping and protein analysis together with complementation assays showed that a protein related to SecA, which is a component of the Sec protein secretion system in a wide range of bacteria, is needed at least for the production of the BauA acinetobactin outer membrane receptor. Furthermore, this derivative was unable to use hemin as an iron source under limiting conditions. Taken together, these results indicate that A. baumannii expresses siderophore-mediated and hemin acquisition functions, although different isolates differ in their iron acquisition capacity. Unexpectedly, the ability of this pathogen to acquire iron depends on the expression of a SecA protein secretion function, which has not been associated with iron acquisition in bacteria.
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Affiliation(s)
- Daniel L Zimbler
- Department of Microbiology, Miami University, Oxford, OH 45056, USA
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Sobecky PA, Hazen TH. Horizontal gene transfer and mobile genetic elements in marine systems. Methods Mol Biol 2009; 532:435-53. [PMID: 19271200 DOI: 10.1007/978-1-60327-853-9_25] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The pool of mobile genetic elements (MGE) in microbial communities consists of viruses, plasmids, and associated elements (insertion sequences, transposons, and integrons) that are either self-transmissible or use mobile plasmids and viruses as vehicles for their dissemination. This mobilome facilitates the horizontal transfer of genes that promote the evolution and adaptation of microbial communities. Efforts to characterize MGEs from microbial populations resident in a variety of ecological habitats have revealed a surprisingly novel and seemingly untapped biodiversity. To better understand the impact of horizontal gene transfer (HGT), as well as the agents that promote HGT in marine ecosystems and to determine whether or not environmental parameters can effect the composition and structure of the mobilome in marine microbial communities, information on the distribution, diversity, and ecological traits of the marine mobilome is presented. In this chapter we discuss recent insights gained from different methodological approaches used to characterize the biodiversity and ecology of MGE in marine environments and their contributions to HGT. In addition, we present case studies that highlight specific HGT examples in coastal, open-ocean, and deep-sea marine ecosystems.
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Landete JM, De las Rivas B, Marcobal A, Muñoz R. Updated molecular knowledge about histamine biosynthesis by bacteria. Crit Rev Food Sci Nutr 2008; 48:697-714. [PMID: 18756395 DOI: 10.1080/10408390701639041] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Histamine poisoning is caused by the ingestion of food containing high levels of histamine, a biogenic amine. Histamine could be expected in virtually all foods that contain proteins or free histidine and that are subject to conditions enabling microbial activity. In most histamine-containing foods the majority of the histamine is generated by decarboxylation of the histidine through histidine decarboxylase enzymes derived from the bacteria present in food. Bacterial histidine decarboxylases have been extensively studied and characterized in different organisms and two different enzymes groups have been distinguished, pyridoxal phosphate- and the pyruvoyl-dependent. Pyridoxal phosphate-dependent histidine decarboxylases are encountered in gram-negative bacteria belonging to various species. Pyruvoyl-dependent histidine decarboxylases are found in gram-positive bacteria and specially in lactic acid bacteria implicated in food fermentation or spoilage. The molecular organization of the genes involved in histamine production have been elucidated in several histamine-producer bacteria. This molecular knowledge has led to the development of molecular methods for the rapid detection of bacteria possessing the ability to produce histamine. The detection of histamine-producer bacteria is of great importance for its potential health hazard as well as from an economic point of view since products exceeding recommended limits can be refused in commercial transactions.
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Affiliation(s)
- José María Landete
- Departamento de Microbiologia, Instituto de Fermentaciones Industriales, CSIC, Madrid, Spain
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Kamruzzaman M, Bhoopong P, Vuddhakul V, Nishibuchi M. Detection of a functional insertion sequence responsible for deletion of the thermostable direct hemolysin gene (tdh) in Vibrio parahaemolyticus. Gene 2008; 421:67-73. [DOI: 10.1016/j.gene.2008.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 05/28/2008] [Accepted: 06/02/2008] [Indexed: 10/22/2022]
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Di Lorenzo M, Stork M, Naka H, Tolmasky ME, Crosa JH. Tandem heterocyclization domains in a nonribosomal peptide synthetase essential for siderophore biosynthesis in Vibrio anguillarum. Biometals 2008; 21:635-48. [PMID: 18553137 DOI: 10.1007/s10534-008-9149-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 05/27/2008] [Indexed: 11/24/2022]
Abstract
Anguibactin, the siderophore produced by Vibrio anguillarum 775, is synthesized via a nonribosomal peptide synthetase (NRPS) mechanism. Most of the genes required for anguibactin biosynthesis are harbored by the pJM1 plasmid. Complete sequencing of this plasmid identified an orf encoding a 108 kDa predicted protein, AngN. In this work we show that AngN is essential for anguibactin biosynthesis and possesses two domains with homology to cyclization (Cy) domains of NRPSs. Substitution by alanine of the aspartic acid residues within a conserved motif of either Cy1 or Cy2 domain demonstrated the importance of these two domains in AngN function during siderophore biosynthesis. Site-directed mutations in both domains (D133A/D575A and D138A/D580A) resulted in anguibactin-deficient phenotypes while mutations in each domain did not abolish siderophore production but caused a reduction in the amounts produced. The mutations D133A/D575A and D138A/D580A also resulted as expected in a dramatic attenuation of the virulence of V. anguillarum 775 highlighting the importance of this gene for the biosynthesis of anguibactin within the vertebrate host. Regulation of the angN gene follows the patterns observed at the iron transport-biosynthesis promoter with angN transcription repressed in the presence of iron and enhanced by AngR and trans-acting factor (TAF) under iron limitation.
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Affiliation(s)
- Manuela Di Lorenzo
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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Biosynthetic and regulatory elements involved in the production of the siderophore vanchrobactin in Vibrio anguillarum. Microbiology (Reading) 2008; 154:1400-1413. [DOI: 10.1099/mic.0.2008/016618-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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