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Vincent AT, Charette SJ. Phylogenetic analysis of the fish pathogen Aeromonas salmonicida underlines the dichotomy between European and Canadian strains for the salmonicida subspecies. JOURNAL OF FISH DISEASES 2017; 40:1241-1247. [PMID: 28105757 DOI: 10.1111/jfd.12595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/06/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Affiliation(s)
- A T Vincent
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Quebec City, QC, Canada
| | - S J Charette
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Quebec City, QC, Canada
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Vincent AT, Trudel MV, Freschi L, Nagar V, Gagné-Thivierge C, Levesque RC, Charette SJ. Increasing genomic diversity and evidence of constrained lifestyle evolution due to insertion sequences in Aeromonas salmonicida. BMC Genomics 2016; 17:44. [PMID: 26753691 PMCID: PMC4709979 DOI: 10.1186/s12864-016-2381-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/06/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Aeromonads make up a group of Gram-negative bacteria that includes human and fish pathogens. The Aeromonas salmonicida species has the peculiarity of including five known subspecies. However, few studies of the genomes of A. salmonicida subspecies have been reported to date. RESULTS We sequenced the genomes of additional A. salmonicida isolates, including three from India, using next-generation sequencing in order to gain a better understanding of the genomic and phylogenetic links between A. salmonicida subspecies. Their relative phylogenetic positions were confirmed by a core genome phylogeny based on 1645 gene sequences. The Indian isolates, which formed a sub-group together with A. salmonicida subsp. pectinolytica, were able to grow at either at 18 °C and 37 °C, unlike the A. salmonicida psychrophilic isolates that did not grow at 37 °C. Amino acid frequencies, GC content, tRNA composition, loss and gain of genes during evolution, pseudogenes as well as genes under positive selection and the mobilome were studied to explain this intraspecies dichotomy. CONCLUSION Insertion sequences appeared to be an important driving force that locked the psychrophilic strains into their particular lifestyle in order to conserve their genomic integrity. This observation, based on comparative genomics, is in agreement with previous results showing that insertion sequence mobility induced by heat in A. salmonicida subspecies causes genomic plasticity, resulting in a deleterious effect on the virulence of the bacterium. We provide a proof-of-concept that selfish DNAs play a major role in the evolution of bacterial species by modeling genomes.
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Affiliation(s)
- Antony T Vincent
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| | - Mélanie V Trudel
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| | - Luca Freschi
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Département de microbiologie-infectiologie et immunologie, Faculté de médecine, Université Laval, Quebec City, QC, Canada.
| | - Vandan Nagar
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
| | - Cynthia Gagné-Thivierge
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| | - Roger C Levesque
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Département de microbiologie-infectiologie et immunologie, Faculté de médecine, Université Laval, Quebec City, QC, Canada.
| | - Steve J Charette
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
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Diamanka A, Loch TP, Cipriano RC, Faisal M. Polyphasic characterization of Aeromonas salmonicida isolates recovered from salmonid and non-salmonid fish. JOURNAL OF FISH DISEASES 2013; 36:949-963. [PMID: 23444966 DOI: 10.1111/jfd.12092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 01/07/2013] [Accepted: 01/08/2013] [Indexed: 06/01/2023]
Abstract
Michigan's fisheries rely primarily upon the hatchery propagation of salmonid fish for release in public waters. One limitation on the success of these efforts is the presence of bacterial pathogens, including Aeromonas salmonicida, the causative agent of furunculosis. This study was undertaken to determine the prevalence of A. salmonicida in Michigan fish, as well as to determine whether biochemical or gene sequence variability exists among Michigan isolates. A total of 2202 wild, feral and hatchery-propagated fish from Michigan were examined for the presence of A. salmonicida. The examined fish included Chinook salmon, Oncorhynchus tshawytscha (Walbaum), coho salmon, O. kisutcha (Walbaum), steelhead trout, O. mykiss (Walbaum), Atlantic salmon, Salmo salar L., brook trout, Salvelinus fontinalis (Mitchill), and yellow perch, Perca flavescens (Mitchill). Among these, 234 fish yielded a brown pigment-producing bacterium that was presumptively identified as A. salmonicida. Further phenotypic and phylogenetic analyses identified representative isolates as Aeromonas salmonicida subsp. salmonicida and revealed some genetic and biochemical variability. Logistic regression analyses showed that infection prevalence varied according to fish species/strain, year and gender, whereby Chinook salmon and females had the highest infection prevalence. Moreover, this pathogen was found in six fish species from eight sites, demonstrating its widespread nature within Michigan.
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Affiliation(s)
- A Diamanka
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
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Roger F, Lamy B, Jumas-Bilak E, Kodjo A, Marchandin H. Ribosomal multi-operon diversity: an original perspective on the genus Aeromonas. PLoS One 2012; 7:e46268. [PMID: 23032081 PMCID: PMC3459834 DOI: 10.1371/journal.pone.0046268] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/28/2012] [Indexed: 12/31/2022] Open
Abstract
16S rRNA gene (rrs) is considered of low taxonomic interest in the genus Aeromonas. Here, 195 Aeromonas strains belonging to populations structured by multilocus phylogeny were studied using an original approach that considered Ribosomal Multi-Operon Diversity. This approach associated pulsed-field gel electrophoresis (PFGE) to assess rrn operon number and distribution across the chromosome and PCR-temporal temperature gel electrophoresis (TTGE) to assess rrs V3 region heterogeneity. Aeromonads harbored 8 to 11 rrn operons, 10 operons being observed in more than 92% of the strains. Intraspecific variability was low or nul except for A. salmonicida and A. aquariorum suggesting that large chromosomic rearrangements might occur in these two species while being extremely rarely encountered in the evolution of other taxa. rrn operon number at 8 as well as PFGE patterns were shown valuable for taxonomic purpose allowing resolution of species complexes. PCR-TTGE revealed a high rate of strains (41.5%) displaying intragenomic rrs heterogeneity. Strains isolated from human samples more frequently displayed intragenomic heterogeneity than strains recovered from non-human and environmental specimens. Intraspecific variability ranged from 0 to 76.5% of the strains. The observation of species-specific TTGE bands, the recovery of identical V3 regions in different species and the variability of intragenomic heterogeneity (1-13 divergent nucleotides) supported the occurrence of mutations and horizontal transfer in aeromonad rrs evolution. Altogether, the presence of a high number of rrn operon, the high proportion of strains harboring divergent rrs V3 region and the previously demonstrated high level of genetic diversity argued in favor of highly adaptative capabilities of aeromonads. Outstanding features observed for A. caviae supported the ongoing process of adaptation to a specialized niche represented by the gut, previously hypothesized. 16S rRNA gene is an informative marker in the genus Aeromonas for both evolutionary and polyphasic taxonomic studies provided that multi-operon fingerprinting approaches are used.
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Affiliation(s)
- Frédéric Roger
- UMR 5119 ECOSYM, Equipe Pathogènes et Environnements, U.F.R. des Sciences Pharmaceutiques et Biologiques, Université Montpellier 1, Montpellier, France
| | - Brigitte Lamy
- UMR 5119 ECOSYM, Equipe Pathogènes et Environnements, U.F.R. des Sciences Pharmaceutiques et Biologiques, Université Montpellier 1, Montpellier, France
- Laboratoire de Bactériologie, Hôpital Arnaud de Villeneuve, Centre Hospitalier Régional Universitaire de Montpellier, Montpellier, France
- Groupe d’Etude Français des Aeromonas (GFA), Lyon, France
| | - Estelle Jumas-Bilak
- UMR 5119 ECOSYM, Equipe Pathogènes et Environnements, U.F.R. des Sciences Pharmaceutiques et Biologiques, Université Montpellier 1, Montpellier, France
- Laboratoire d’Hygiène hospitalière, Centre Hospitalier Régional Universitaire de Montpellier, Montpellier, France
| | - Angeli Kodjo
- Groupe d’Etude Français des Aeromonas (GFA), Lyon, France
- CNRS UMR 5557 Ecologie microbienne, VetAgro Sup Campus vétérinaire de Lyon, Université Claude Bernard Lyon 1, Marcy-l’Étoile, France
| | | | - Hélène Marchandin
- UMR 5119 ECOSYM, Equipe Pathogènes et Environnements, U.F.R. des Sciences Pharmaceutiques et Biologiques, Université Montpellier 1, Montpellier, France
- Laboratoire de Bactériologie, Hôpital Arnaud de Villeneuve, Centre Hospitalier Régional Universitaire de Montpellier, Montpellier, France
- * E-mail:
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Roger F, Marchandin H, Jumas-Bilak E, Kodjo A, Lamy B. Multilocus genetics to reconstruct aeromonad evolution. BMC Microbiol 2012; 12:62. [PMID: 22545815 PMCID: PMC3487998 DOI: 10.1186/1471-2180-12-62] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Accepted: 04/30/2012] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Aeromonas spp. are versatile bacteria that exhibit a wide variety of lifestyles. In an attempt to improve the understanding of human aeromonosis, we investigated whether clinical isolates displayed specific characteristics in terms of genetic diversity, population structure and mode of evolution among Aeromonas spp. A collection of 195 Aeromonas isolates from human, animal and environmental sources was therefore genotyped using multilocus sequence analysis (MLSA) based on the dnaK, gltA, gyrB, radA, rpoB, tsf and zipA genes. RESULTS The MLSA showed a high level of genetic diversity among the population, and multilocus-based phylogenetic analysis (MLPA) revealed 3 major clades: the A. veronii, A. hydrophila and A. caviae clades, among the eleven clades detected. Lower genetic diversity was observed within the A. caviae clade as well as among clinical isolates compared to environmental isolates. Clonal complexes, each of which included a limited number of strains, mainly corresponded to host-associated subsclusters of strains, i.e., a fish-associated subset within A. salmonicida and 11 human-associated subsets, 9 of which included only disease-associated strains. The population structure was shown to be clonal, with modes of evolution that involved mutations in general and recombination events locally. Recombination was detected in 5 genes in the MLSA scheme and concerned approximately 50% of the STs. Therefore, these recombination events could explain the observed phylogenetic incongruities and low robustness. However, the MLPA globally confirmed the current systematics of the genus Aeromonas. CONCLUSIONS Evolution in the genus Aeromonas has resulted in exceptionally high genetic diversity. Emerging from this diversity, subsets of strains appeared to be host adapted and/or "disease specialized" while the A. caviae clade displayed an atypical tempo of evolution among aeromonads. Considering that A. salmonicida has been described as a genetically uniform pathogen that has adapted to fish through evolution from a variable ancestral population, we hypothesize that the population structure of aeromonads described herein suggested an ongoing process of adaptation to specialized niches associated with different degrees of advancement according to clades and clusters.
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Affiliation(s)
- Frédéric Roger
- Laboratoire de Bactériologie-Virologie, Université Montpellier, France
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Aujoulat F, Roger F, Bourdier A, Lotthé A, Lamy B, Marchandin H, Jumas-Bilak E. From environment to man: genome evolution and adaptation of human opportunistic bacterial pathogens. Genes (Basel) 2012; 3:191-232. [PMID: 24704914 PMCID: PMC3899952 DOI: 10.3390/genes3020191] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 02/29/2012] [Accepted: 02/29/2012] [Indexed: 02/07/2023] Open
Abstract
Environment is recognized as a huge reservoir for bacterial species and a source of human pathogens. Some environmental bacteria have an extraordinary range of activities that include promotion of plant growth or disease, breakdown of pollutants, production of original biomolecules, but also multidrug resistance and human pathogenicity. The versatility of bacterial life-style involves adaptation to various niches. Adaptation to both open environment and human specific niches is a major challenge that involves intermediate organisms allowing pre-adaptation to humans. The aim of this review is to analyze genomic features of environmental bacteria in order to explain their adaptation to human beings. The genera Pseudomonas, Aeromonas and Ochrobactrum provide valuable examples of opportunistic behavior associated to particular genomic structure and evolution. Particularly, we performed original genomic comparisons among aeromonads and between the strictly intracellular pathogens Brucella spp. and the mild opportunistic pathogens Ochrobactrum spp. We conclude that the adaptation to human could coincide with a speciation in action revealed by modifications in both genomic and population structures. This adaptation-driven speciation could be a major mechanism for the emergence of true pathogens besides the acquisition of specialized virulence factors.
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Affiliation(s)
- Fabien Aujoulat
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Frédéric Roger
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Alice Bourdier
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Anne Lotthé
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Brigitte Lamy
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Hélène Marchandin
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Estelle Jumas-Bilak
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
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The genome of Aeromonas salmonicida subsp. salmonicida A449: insights into the evolution of a fish pathogen. BMC Genomics 2008; 9:427. [PMID: 18801193 PMCID: PMC2556355 DOI: 10.1186/1471-2164-9-427] [Citation(s) in RCA: 217] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 09/18/2008] [Indexed: 12/04/2022] Open
Abstract
Background Aeromonas salmonicida subsp. salmonicida is a Gram-negative bacterium that is the causative agent of furunculosis, a bacterial septicaemia of salmonid fish. While other species of Aeromonas are opportunistic pathogens or are found in commensal or symbiotic relationships with animal hosts, A. salmonicida subsp. salmonicida causes disease in healthy fish. The genome sequence of A. salmonicida was determined to provide a better understanding of the virulence factors used by this pathogen to infect fish. Results The nucleotide sequences of the A. salmonicida subsp. salmonicida A449 chromosome and two large plasmids are characterized. The chromosome is 4,702,402 bp and encodes 4388 genes, while the two large plasmids are 166,749 and 155,098 bp with 178 and 164 genes, respectively. Notable features are a large inversion in the chromosome and, in one of the large plasmids, the presence of a Tn21 composite transposon containing mercury resistance genes and an In2 integron encoding genes for resistance to streptomycin/spectinomycin, quaternary ammonia compounds, sulphonamides and chloramphenicol. A large number of genes encoding potential virulence factors were identified; however, many appear to be pseudogenes since they contain insertion sequences, frameshifts or in-frame stop codons. A total of 170 pseudogenes and 88 insertion sequences (of ten different types) are found in the A. salmonicida genome. Comparison with the A. hydrophila ATCC 7966T genome reveals multiple large inversions in the chromosome as well as an approximately 9% difference in gene content indicating instances of single gene or operon loss or gain. A limited number of the pseudogenes found in A. salmonicida A449 were investigated in other Aeromonas strains and species. While nearly all the pseudogenes tested are present in A. salmonicida subsp. salmonicida strains, only about 25% were found in other A. salmonicida subspecies and none were detected in other Aeromonas species. Conclusion Relative to the A. hydrophila ATCC 7966T genome, the A. salmonicida subsp. salmonicida genome has acquired multiple mobile genetic elements, undergone substantial rearrangement and developed a significant number of pseudogenes. These changes appear to be a consequence of adaptation to a specific host, salmonid fish, and provide insights into the mechanisms used by the bacterium for infection and avoidance of host defence systems.
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Soto E, Mauel MJ, Karsi A, Lawrence ML. Genetic and virulence characterization of Flavobacterium columnare from channel catfish (Ictalurus punctatus). J Appl Microbiol 2007; 104:1302-10. [PMID: 18005349 DOI: 10.1111/j.1365-2672.2007.03632.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To develop a method for conducting pulsed-field gel electrophoresis (PFGE) on Flavobacterium columnare, to use PFGE to characterize F. columnare channel catfish isolates, and to determine whether variation in pathogenic potential exists in F. columnare isolates from channel catfish. METHODS AND RESULTS On the basis of PFGE-derived profiles, similarity dendrograms constructed for more than 30 F. columnare isolates showed two major genetic groups with more than 60% similarity. Channel catfish fingerlings challenged with PFGE group A isolates by bath immersion had significantly higher average mortalities (>60%) than fish challenged with PFGE group B isolates (<9%). However, abrasion and skin mucus removal made channel catfish fingerlings susceptible to disease caused by group B isolates following immersion exposure. CONCLUSION Our results suggest that two genetic divisions of F. columnare channel catfish isolates exist, and that isolates in PFGE group A isolates tend to be more pathogenic to immunocompetent channel catfish fingerlings than PFGE group B isolates. SIGNIFICANCE AND IMPACT OF THE STUDY PFGE is a potentially useful tool for determining whether F. columnare isolates are more likely to be primary or secondary pathogens. Pathogenesis research for columnaris disease in catfish should focus on pathogenic isolates from PFGE group A.
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Affiliation(s)
- E Soto
- Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS, USA
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Fehr D, Casanova C, Liverman A, Blazkova H, Orth K, Dobbelaere D, Frey J, Burr SE. AopP, a type III effector protein of Aeromonas salmonicida, inhibits the NF-κB signalling pathway. Microbiology (Reading) 2006; 152:2809-2818. [PMID: 16946275 DOI: 10.1099/mic.0.28889-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aeromonas salmonicida subsp. salmonicida contains a functional type III secretion system that is responsible for the secretion of the ADP-ribosylating toxin AexT. In this study, the authors identified AopP as a second effector protein secreted by this system. The aopP gene was detected in both typical and atypical A. salmonicida isolates and was found to be encoded on a small plasmid of approximately 6.4 kb. Sequence analysis indicates that AopP is a member of the YopJ family of effector proteins, a group of proteins that interfere with mitogen-activated protein kinase (MAPK) and/or nuclear factor kappa B (NF-κB) signalling pathways. AopP inhibits the NF-κB pathway downstream of IκB kinase (IKK) activation, while a catalytically inactivated mutant, AopPC177A, does not possess this inhibitory effect. Unlike other effectors of the YopJ family, such as YopJ and VopA, AopP does not inhibit the MAPK signalling pathway.
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Affiliation(s)
- Désirée Fehr
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, Universität Bern, Länggassstrasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Carlo Casanova
- Division of Molecular Pathology, Vetsuisse Faculty, Universität Bern, Länggassstrasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Amy Liverman
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, USA
| | - Hana Blazkova
- Division of Molecular Pathology, Vetsuisse Faculty, Universität Bern, Länggassstrasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, USA
| | - Dirk Dobbelaere
- Division of Molecular Pathology, Vetsuisse Faculty, Universität Bern, Länggassstrasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Joachim Frey
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, Universität Bern, Länggassstrasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Sarah E Burr
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, Universität Bern, Länggassstrasse 122, Postfach, CH-3001 Bern, Switzerland
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Lund V, Børdal S, Kjellsen O, Mikkelsen H, Schrøder MB. Comparison of antibody responses in Atlantic cod (Gadus morhua L.) to Aeromonas salmonicida and Vibrio anguillarum. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2006; 30:1145-55. [PMID: 16616955 DOI: 10.1016/j.dci.2006.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 01/31/2006] [Accepted: 02/21/2006] [Indexed: 05/08/2023]
Abstract
The immune system of Atlantic cod (Gadus morhua L.) differ from other bony fish species in that no or only very low increases in antibody levels are detected post-immunization with Vibrio salmonicida or V. anguillarum. Here, we report the results from the first study on comparison of antibody responses in cod to Aeromonas salmonicida and V. anguillarum. A. salmonicida appear to induce a stronger antibody response in cod compared to V. anguillarum, and more individuals immunized with A. salmonicida revealed a response compared to those immunized with V. anguillarum. The antibody responses to both bacterial species were mainly toward LPS, and the results indicate that cod antibodies are able to differentiate between LPS antigens from typical and atypical A. salmonicida strains.
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Affiliation(s)
- Vera Lund
- Fiskeriforskning, Norwegian Institute of Fisheries and Aquaculture Research, N-9291 Tromsø, Norway
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Abstract
The prevalence of the two-chromosome configuration was investigated in 34 species of vibrios and closely related species. Pulsed-field gel electrophoresis of undigested genomic DNA suggested that vibrios commonly have two chromosomes. The size of the large chromosome is predominantly within a narrow range (3.0 to 3.3 Mb), whereas the size of the small chromosome varies considerably among the vibrios (0.8 to 2.4 Mb). This fact suggests that the structure of the small chromosome is more flexible than that of the large chromosome during the evolution of vibrios.
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Affiliation(s)
- Kazuhisa Okada
- Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Boyd J, Williams J, Curtis B, Kozera C, Singh R, Reith M. Three small, cryptic plasmids from Aeromonas salmonicida subsp. salmonicida A449. Plasmid 2003; 50:131-44. [PMID: 12932739 DOI: 10.1016/s0147-619x(03)00058-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The nucleotide sequences of three small (5.2-5.6 kb) plasmids from Aeromonas salmonicida subsp. salmonicida A449 are described. Two of the plasmids (pAsa1 and pAsa3) use a ColE2-type replication mechanism while the third (pAsa2) is a ColE1-type replicon. Insertions in the Rep protein and oriV region of the ColE2-type plasmids provide subtle differences that allow them to be maintained compatibly. All three plasmids carry genes for mobilization (mobABCD), but transfer genes are absent and are presumably provided in trans. Two of the plasmids, pAsa1 and pAsa3, carry toxin-antitoxin gene pairs, most probably to ensure plasmid stability. One open reading frame (ORF), orf1, is conserved in all three plasmids, while other ORFs are plasmid-specific. A survey of A. salmonicida strains indicates that pAsa1 and pAsa2 are present in all 12 strains investigated, while pAsa3 is present in 11 and a fourth plasmid, pAsal1, is present in 7.
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Affiliation(s)
- Jessica Boyd
- National Research Council Institute for Marine Biosciences, 1411 Oxford Street, Halifax, NS, Canada B3H 3Z1.
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Langefors A, Lohm J, Grahn M, Andersen O, von Schantz T. Association between major histocompatibility complex class IIB alleles and resistance to Aeromonas salmonicida in Atlantic salmon. Proc Biol Sci 2001; 268:479-85. [PMID: 11296859 PMCID: PMC1088630 DOI: 10.1098/rspb.2000.1378] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have tested the importance of genetic variation in the major histocompatibility complex (MHC) class IIB in Atlantic salmon (Salmo salar) for survival after challenge with a highly virulent bacterial pathogen. Forty juvenile full siblings from each of 120 families were infected with the bacterium Aeromonas salmonicida, which causes high mortality in salmon due to furunculosis. Fishes from high-resistance (HR, < 35% mortality) and low-resistance (L,R, > 80% mortality) families were screened for their MHC class IIB genotypes using the denaturing gradient gel electrophoresis (DGGE) technique. The exon 2 sequences, encoding the major part of the peptide-binding region, were established for each DGGE fragment. One allele, e, containing a missense single base substitution was significantly more prevalent in HR families than in LR families. An odds-ratio test showed that broods carrying this allele had a 12-fold higher chance of being HR than broods without the e allele. A second allele, i, showed significantly higher frequencies in uninfected and surviving individuals than in infected dead individuals. A third allele, j, tended to more prevalent both in LR families and in individuals that had died of the infection. There was no correlation between MHC heterozygosity and resistance to A. salmonicida. Our results support the hypothesis that MHC polymorphism is maintained through pathogen-driven selection acting by means of frequency-dependent selection rather than heterozygous advantage.
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Affiliation(s)
- A Langefors
- Department of Animal Ecology, Lund University, Sweden.
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Villari P, Crispino M, Montuori P, Stanzione S. Prevalence and molecular characterization of Aeromonas spp. in ready-to-eat foods in Italy. J Food Prot 2000; 63:1754-7. [PMID: 11131903 DOI: 10.4315/0362-028x-63.12.1754] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A survey was carried out in Italy to ascertain the prevalence of Aeromonas spp. in ready-to-eat foods (vegetables, cheeses, meat products, and ice creams) and the level of molecular heterogeneity of the isolates found by macrorestriction analysis of genomic DNA with pulsed-field gel electrophoresis (PFGE). In total, 46 (14.4%) of the 320 food samples examined were found positive for Aeromonas spp. The highest percentages of isolation were discovered in vegetables, particularly lettuce (45.0%), endive (40.0%), and rucola (20.0%). Ricotta was the only cheese type analyzed that showed a high frequency of isolation (45.0%). Among meat products, salami and raw ham (25.0% of samples positive) and, to a lesser extent, baloney (5.0%) were found positive for Aeromonas spp. Aeromonas hydrophila was the most common isolate from foods of animal origin, whereas Aeromonas caviae was the dominant species in vegetables. No motile aeromonads were found in ice cream samples. Aeromonas isolates showed a high level of genetic heterogeneity, because 24 PFGE patterns were identified among 27 A. hydrophila strains and 20 PFGE patterns were found in 23 A. caviae isolates. In conclusion, consumers of ready-to-eat foods in Italy are regularly exposed to many genetically distinct strains of A. hydrophila and A. caviae without evident signs of malaise, and therefore, few of these strains, if any, are likely to be pathogenic.
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Affiliation(s)
- P Villari
- Department of Health and Preventive Sciences, University Federico II, Naples, Italy.
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Frangeul L, Nelson KE, Buchrieser C, Danchin A, Glaser P, Kunst F. Cloning and assembly strategies in microbial genome projects. MICROBIOLOGY (READING, ENGLAND) 1999; 145 ( Pt 10):2625-34. [PMID: 10537184 DOI: 10.1099/00221287-145-10-2625] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- L Frangeul
- Laboratoire de Génomique des Microorganismes Pathogènes, Institut Pasteur, Paris, France
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