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structural characterization of the lipid a region of aeromonas salmonicida subsp. salmonicida lipopolysaccharide.the lipid a components of aeromonas salmonicida subsp. salmonicida from strains a449, 80204-1 and an in vivo rough isolate were isolated by mild acid hydrolysis of the lipopolysaccharide. structural studies carried out by a combination of fatty acid, electrospray ionization-mass spectrometry and nuclear magnetic resonance analyses confirmed that the structure of lipid a was conserved among different isolates of a. salmonicida subsp. salmonicida. all analyzed strains contained three major lipid a ...200617049500
structural studies of the core region of aeromonas salmonicida subsp. salmonicida lipopolysaccharide.the core oligosaccharide structure of the in vivo derived rough phenotype of aeromonas salmonicida subsp. salmonicida was investigated by a combination of compositional, methylation, ce-ms and one- and two-dimensional nmr analyses and established as the following: [carbohydrate: see text] where r=alpha-d-galp-(1-->4)-beta-d-galpnac-(1--> or alpha-d-galp-(1--> (approx. ratio 4:3). comparative ce-ms analysis of a. salmonicida subsp. salmonicida core oligosaccharides from strains a449, 80204-1 and ...200616297894
identification of the major outer membrane proteins of aeromonas salmonicida.aeromonas salmonicida subsp. salmonicida is a gram-negative bacterium that is the etiological agent of furunculosis, a serious infectious disease of salmonids. aeromonas spp. are ubiquitous waterborne bacteria responsible for a wide spectrum of diseases among aquatic organisms and humans. bacterial outer membrane proteins (omps) play a significant role in virulence as they comprise the outermost surface in contact with host cells and immune defense factors. to identify the major omps of a. salmo ...200516465831
attenuated virulence of an aeromonas salmonicida subsp. salmonicida type iii secretion mutant in a rainbow trout model.aeromonas salmonicida subsp. salmonicida is the causative agent of furunculosis, a severe systemic disease affecting salmonid fish. this bacterium contains a type iii protein secretion system that is responsible for the secretion and translocation of the adp-ribosylating toxin, aext, into the cytosol of fish cells. this study showed that inactivation of the type iii secretion system by marker-replacement mutagenesis of the gene ascv, which encodes an inner-membrane component of the type iii secr ...200515942017
bacterial vaccines for fish--an update of the current situation worldwide.during the last few years, the use of vaccines for disease prevention in aquaculture has expanded both with regard to the number of fish species and number of microbial diseases. according to the responses to a questionnaire received from 41 countries, vaccination is used in the commercial aquaculture of species like atlantic salmon (salmo salar), rainbow trout (oncorhynchus mykiss), sea bass (dicentrarchus labrax), sea bream (sparus aurata), barramundi (lates calcarifer), tilapia (tilapia spp), ...200515962470
standardization of a broth microdilution susceptibility testing method to determine minimum inhibitory concentrations of aquatic bacteria.a multiple laboratory study was conducted in accordance with the standards established by the clinical and laboratory standards institute (clsi), formerly the national committee for clinical laboratory standards (nccls), for the development of quality control (qc) ranges using dilution antimicrobial susceptibility testing methods for bacterial isolates from aquatic animal species. qc ranges were established for escherichia coli atcc 25922 and aeromonas salmonicida subsp. salmonicida atcc 33658 w ...200515997819
metabolic changes in atlantic salmon exposed to aeromonas salmonicida detected by 1h-nuclear magnetic resonance spectroscopy of plasma.1h-nmr (nuclear magnetic resonance)-based chemometric methods have been applied for the first time to investigate changes in the plasma metabolite profiles of atlantic salmon salmo salar as a result of exposure to aeromonas salmonicida subsp. salmonicida, a gram-negative bacterium that is the etiological agent of furunculosis. plasma samples were obtained from salmon that survived 21 d post exposure to a. salmonicida, and from a control group maintained under similar conditions. 1d 1h-nmr spectr ...200516060263
differential proteomic analysis of aeromonas salmonicida outer membrane proteins in response to low iron and in vivo growth conditions.aeromonas salmonicida subsp. salmonicida is the etiological agent of furunculosis, a serious infectious disease of salmonids. bacterial phenotypes are known to change in vivo compared to the in vitro state. proteomic analysis of in vivo phenotypes is usually not possible due to insufficient biomass. using an in vivo growth chamber model, the pathogenic fish bacterium a. salmonicida was cultured in pure culture in vivo in its host, the atlantic salmon, to obtain sufficient biomass to allow proteo ...200415048988
simultaneous detection of marine fish pathogens by using multiplex pcr and a dna microarray.we coupled multiplex pcr and a dna microarray to construct an assay suitable for the simultaneous detection of five important marine fish pathogens (vibrio vulnificus, listonella anguillarum, photobacterium damselae subsp. damselae, aeromonas salmonicida subsp. salmonicida, and vibrio parahaemolyticus). the array was composed of nine short oligonucleotide probes (25-mer) complementary to seven chromosomal loci (cyt, rpon, gyrb, toxr, urec, dly, and vapa) and two plasmid-borne loci (fata and a.sa ...200415070982
influence of chronic exposure to treated sewage effluent on the distribution of white blood cell populations in rainbow trout (oncorhynchus mykiss) spleen.impairment of immune function in aquatic animals has been proposed as a possible consequence of low-level contamination of surface waters with anthropogenic substances such as through the discharge of wastewater into rivers, lakes, and oceans. the study at hand investigated the effects of chronic (32 weeks) exposure to sewage treatment plant (stp) effluent on the prevalence and distribution of different leucocyte populations in spleen samples of rainbow trout (oncorhynchus mykiss). to simulate a ...200415310861
effects of treated sewage effluent on immune function in rainbow trout (oncorhynchus mykiss).in this study, the immune reactions of rainbow trout (oncorhynchus mykiss) were examined, after exposure to 10, 30 and 70% of tertiary-treated municipal sewage effluent for 27 days. exposures were conducted concurrently with and without an immune challenge using intraperitoneal injections of inactivated aeromonas salmonicida salmonicida. due to the time required to prepare and analyse samples, fish sampling was conducted over two consecutive days. there was no trout mortality for any of the expe ...200415588644
in vitro inhibition of microbial flora of fish by nisin and lactoperoxidase system.to test the antimicrobial effects of nisin and lactoperoxidase system (lp system) against sardines flora. this study is part of a programme designed to investigate the preservability of fish using these inhibitors as potential biopreservatives.200414687217
association of type iii secretion genes with virulence of aeromonas salmonicida subsp. salmonicida.aeromonas salmonicida subsp. salmonicida possesses a number of potential virulence factors, including a recently identified plasmid-encoded type iii secretion system. a number of field isolates of a. salmonicida subsp. salmonicida were examined for the presence of type iii secretion genes. using in vitro experiments, it was found that field isolates containing such genes are cytotoxic to fish cell lines, whereas those that lack these genes are not. using a rainbow trout in vivo model, the virule ...200314735937
removal of fish pathogenic bacteria in biological sand filters.documentation is required to evaluate the use of infiltration systems as an alternative method for removal of fish pathogenic bacteria in wastewater from fish-farms. this study was performed to investigate the removal of bacterial fish pathogens in biological sand filters. a second aim of the study was to evaluate the bacteria used in the study in order to find a suitable model organism for future experiments. low-strength wastewater from an inland freshwater salmonid farm was intermittently loa ...200312753839
molecular characterization and quantitative analysis of superoxide dismutases in virulent and avirulent strains of aeromonas salmonicida subsp. salmonicida.aeromonas salmonicida subsp. salmonicida is a facultatively intracellular gram-negative bacterium that is the etiological agent of furunculosis, a bacterial septicemia of salmonids that causes significant economic loss to the salmon farming industry. the mechanisms by which a. salmonicida evades intracellular killing may be relevant in understanding virulence and the eventual design of appropriate treatment strategies for furunculosis. we have identified two open reading frames (orfs) and relate ...200312867441
type iii secretion genes in aeromonas salmonicida subsp salmonicida are located on a large thermolabile virulence plasmid.type iii secretion genes in aeromonas salmonicida subsp. salmonicida are located on a large plasmid of approximately 140 kb. cultivation of this organism at elevated temperatures such as 25 degrees c can, however, result in loss of this plasmid. this is accompanied by a loss of virulence for cultured fish cells.200312904401
three small, cryptic plasmids from aeromonas salmonicida subsp. salmonicida a449.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 pre ...200312932739
antimicrobial susceptibility testing of aquatic bacteria: quality control disk diffusion ranges for escherichia coli atcc 25922 and aeromonas salmonicida subsp. salmonicida atcc 33658 at 22 and 28 degrees c.quality control (qc) ranges for disk diffusion susceptibility testing of aquatic bacterial isolates were proposed as a result of a multilaboratory study conducted according to procedures established by the national committee for clinical laboratory standards (nccls). ranges were proposed for escherichia coli atcc 25922 and aeromonas salmonicida subsp. salmonicida atcc 33658 at 22 and 28 degrees c for nine different antimicrobial agents (ampicillin, enrofloxacin, erythromycin, florfenicol, gentam ...200312958263
the adp-ribosylating toxin, aext, from aeromonas salmonicida subsp. salmonicida is translocated via a type iii secretion pathway.aext is an extracellular adp ribosyltransferase produced by the fish pathogen aeromonas salmonicida subsp. salmonicida. the protein is secreted by the bacterium via a recently identified type iii secretion system. in this study, we have identified a further 12 open reading frames that possess high homology to genes encoding both structural and regulatory components of the yersinia type iii secretion apparatus. using marker replacement mutagenesis of aopb, the a. salmonicida subsp. salmonicida ho ...200314594831
characterization of an adp-ribosyltransferase toxin (aext) from aeromonas salmonicida subsp. salmonicida.an adp-ribosylating toxin named aeromonas salmonicida exoenzyme t (aext) in a. salmonicida subsp. salmonicida, the etiological agent of furunculosis in fish, was characterized. gene aext, encoding toxin aext, was cloned and characterized by sequence analysis. aext shows significant sequence similarity to the exos and exot exotoxins of pseudomonas aeruginosa and to the yope cytotoxin of different yersinia species. the aext gene was detected in all of the 12 a. salmonicida subsp. salmonicida strai ...200211889090
characterization of carnobacterium divergens strain 6251 isolated from intestine of arctic charr (salvelinus alpinus l.).an atypical strain of carnobacterium divergens, strain 6251, was isolated from the small intestine of arctic charr (salvelinus alpinus l.), fed high dietary carbohydrate. this strain showed marked growth inhibitory effects in vitro against the fish pathogens aeromonas salmonicida subsp. salmonicida (furunculosis), vibrio anguillarum (vibriosis) and vibrio viscocus (winter ulcer). the strain is a non-motile gram-positive psychrotrophic rod that lacks both catalase and oxidase, grows at ph 9.1 (ct ...200212086178
evidence for a type iii secretion system in aeromonas salmonicida subsp. salmonicida.aeromonas salmonicida subsp. salmonicida, the etiological agent of furunculosis, is an important fish pathogen. we have screened this bacterium with a broad-host-range probe directed against yscv, the gene that encodes the archetype of a highly conserved family of inner membrane proteins found in every known type iii secretion system. this has led to the identification of seven open reading frames that encode homologues to proteins functioning within the type iii secretion systems of yersinia sp ...200212374830
class 1 integrons mediate antibiotic resistance in the fish pathogen aeromonas salmonicida worldwide.the presence of class 1 integrons was investigated in 38 sulfonamide-resistant strains of aeromonas salmonicida subsp. salmonicida, atypical a. salmonicida and escherichia coli conjugants with r plasmids originating from a. salmonicida. the strains originated from finland, france, japan, norway, scotland, switzerland, and the united states. additional resistance determinants in strains with class 1 integrons were also determined. of 21 strains containing a class 1 integron, 19 had a single gene ...200111759088
bath exposure of atlantic halibut (hippoglossus hippoglossus l.) yolk sac larvae to bacterial lipopolysaccharide (lps): absorption and distribution of the lps and effect on fish survival.radiolabelled bacterial lipopolysaccharide (3h-lps) obtained from aeromonas salmonicida subsp. salmonicida was added to the petri dishes containing yolk sac larvae of atlantic halibut (hippoglossus hippoglossus l.). the larvae were exposed either to 6.25, 12.5, 25, 50 or 100 micrograms 3h-lps ml-1. the uptake was both dependent on the lps concentration and the time of exposure. after 5 days of exposure, each larva contained 1.8-7.4 ng 3h-lps dependent on the initial concentration. after 10 days ...200010938728
functional tn5393-like transposon in the r plasmid pras2 from the fish pathogen aeromonas salmonicida subspecies salmonicida isolated in norway.tn5393c containing stra-strb was identified as part of r plasmid pras2 from the fish pathogen aeromonas salmonicida subsp. salmonicida. this is the first time an intact and active transposon in the tn5393 family has been reported in an ecological niche other than an agricultural habitat.200011097945
identification and characterization of carnobacteria associated with the gills of atlantic salmon (salmo salar l.).using the surface plate technique, the population level of aerobic bacteria, occurring in the gills of atlantic salmon (salmo salar l.), was determined to be approximately 3 x 10(4) g(-1). of 100 isolates investigated, 58 were gram-negative. out of the 42 gram-positive isolates, 26 belonged to the carnobacteria, of which ten were further identified on the basis of 16s rdna sequence analysis and aflp fingerprinting. all were identified as carnobacterium piscicola-like. these carnobacteria strains ...200011249022
peroxide-inducible catalase in aeromonas salmonicida subsp. salmonicida protects against exogenous hydrogen peroxide and killing by activated rainbow trout, oncorhynchus mykiss l., macrophages.aeromonas salmonicida subsp. salmonicida expresses a single cytoplasmically located catalase which was found to be inducible by exposure to 20 microm hydrogen peroxide in mid-exponential phase resulting in a 4 fold increase in activity. subsequent exposure to 2 mm peroxide in late-exponential/early-stationary phase resulted in further induction of catalase activity which increased to 20 fold higher levels than those found in uninduced cultures. exponentially induced cultures were protected again ...199910089155
efficacy of orally administered oxolinic acid and vetoquinol, an oxolinic acid ester, for the treatment of furunculosis in atlantic salmon salmo salar held in seawater.this study was performed to determine the efficacy of orally administered oxolinic acid and vetoquinol, an oxolinic acid ester, in the treatment of experimental induced furunculosis in atlantic salmon salmo salar held in seawater. two strains of the causative bacterium aeromonas salmonicida subsp. salmonicida, 1 sensitive (vi-88/09/03175) and 1 resistant (3475/90) to oxolinic acid, were used. in 2 trials, cohabitational challenges were performed by introducing 8 fish challenged in advance by an ...199910439903
sialic acid-binding lectin with antibacterial activity from the horse mussel: further characterization and immunolocalization.a heterogeneous sialic acid-binding lectin with affinity for bacterial lps was isolated and partially characterized from hemolymph of the horse mussel modiolus modiolus.(1) using two-dimensional electrophoresis with immobilized ph gradients, the lectin revealed three subunits with different molecular weight and isoelectric points (pi); mr14 (pi approximately 5.1 and approximately 5.5), 17.5 (pi approximately 5.5) and 20 (pi approximately 4.9) kda. the affinity purified lectin existed in its nati ...19989639084
siderophore production by aeromonas salmonicida subsp. salmonicida. lack of strain specificity.siderophore production, presence of iron-regulated outer membrane proteins and siderophore specificity was determined among 17 isolates of aeromonas salmonicida subsp. salmonicida obtained from spain and scotland. all grew in the presence of ethylenediamine di(o-hydroxyphenylacetic acid) (edda) and siderophore production was detected using chrome azurol s (cas) agar, confirming the presence of a high-affinity siderophore iron-uptake mechanism. the arnow test confirmed that all isolates produced ...19989684314
haemorrhagic septicaemia by aeromonas salmonicida subsp. salmonicida in a black-tip reef shark (carcharhinus melanopterus).one black-tip reef shark (carcharhinus melanopterus) was found dead without previous signs of disease. major lesions consisted in cutaneous erythema, mainly at the base of the fins, focal to diffuse inflammatory lesions in gills and intestinal wall, and discrete haemorrhages in the same organs, liver and kidneys. microcolonies of gram-negative rods were observed in the lamina propia of gills, underneath the intestinal mucosa and randomly distributed in the renal and hepatic parenchymas. also, em ...19989780832
in vivo production of a-protein, lipopolysaccharide, iron-regulated outer membrane proteins and 70-kda serine protease by aeromonas salmonicida subsp. salmonicida.using specific immunostaining of western blots, the in vivo expression of several putative virulence factors of aeromonas salmonicida subsp. salmonicida was demonstrated in infected muscle tissue of atlantic salmon and rainbow trout. three virulent isolates of a. salmonicida were used. one isolate was chosen because in vitro it was apparently a non-producer of the 70-kda serine protease. infected furuncle tissue was centrifuged and samples of the pellet and supernatant probed for evidence that t ...19979141656
rapd analysis of aeromonas salmonicida and aeromonas hydrophila.the randomly amplified polymorphic dna (rapd) technique was used to analyse the genetic differentiation of 13 strains of aeromonas salmonicida subsp. salmonicida, and seven strains of aer. hydrophila. reproducible profiles of genomic dna fingerprints were generated by polymerase chain reaction (pcr) using a single randomly designed primer. the rapd profiles of all the non-motile aeromonads, aer. salmonicida subsp. salmonicida were identical. however, profiles of the motile aeromonads, aer. hydro ...19957592114
phenotypic and molecular characteristics of aeromonas salmonicida subsp. salmonicida isolated in southern and northern finland.aeromonas salmonicida subsp. salmonicida causes outbreaks of furunculosis in salmonid fish. furunculosis was first detected in finland in 1986 on fish farms located on the finnish coast of the bothnian bay. molecular methods, sds-page, ribotyping, randomly amplified polymorphic dna (rapd) and plasmid profile analysis as well as phenotypic characteristics (biochemical characteristics, maximum growth temperature, pigment and elastase production) were used both for typing the strains and to study t ...19957665387
vaccination in european salmonid aquaculture: a review of practices and prospects.disease control by vaccination is widely used in european salmonid aquaculture against vibriosis (vibrio anguillarum), cold-water vibriosis (vibrio salmonicida), yersiniosis or enteric redmouth disease (yersinia ruckeri) and furunculosis (aeromonas salmonicida subsp. salmonicida). the vaccines against the vibrio spp. and y. ruckeri have proven effective especially when administered by injection. furunculosis vaccines have been less successful and have relied on combination with potent adjuvants ...19957735870
characterization of aeromonas salmonicida subsp. salmonicida: a comparative study of strains of different geographic origin.a total of 130 strains of the fish pathogen aeromonas salmonicida isolated in denmark, norway, scotland, canada and the usa were examined. the strains originated from farmed salmonid fish. the biochemical, physiological and serological characteristics, antibiotic resistance patterns and cell surface-related properties were compared. aeromonas salmonicida was found to be remarkably consistent in general cultural and biochemical characteristics. it is noteworthy that the strains were positive in t ...19947928780
transfer of multiple drug resistance plasmids between bacteria of diverse origins in natural microenvironments.plasmids harboring multiple antimicrobial-resistance determinants (r plasmids) were transferred in simulated natural microenvironments from various bacterial pathogens of human, animal, or fish origin to susceptible strains isolated from a different ecological niche. r plasmids in a strain of the human pathogen vibrio cholerae o1 e1 tor and a bovine escherichia coli strain were conjugated to a susceptible strain of the fish pathogenic bacterium aeromonas salmonicida subsp. salmonicida in marine ...199411865872
a comparison of the amino acid sequence of the serine protease of the fish pathogen aeromonas salmonicida subsp. salmonicida with those of other subtilisin-type enzymes relative to their substrate-binding sites.the amino acid sequence of the so-called 70 kda (actually 64 kda) serine protease secreted by the gram-negative fish pathogen aeromonas salmonicida has been determined. it shows a high degree of homology with the complete sequence of other bacterial serine proteases which, with molecular masses of approximately 30 kda, are less than half its size. this homology is particularly marked in regions adjacent to the catalytic triad asp32, his64 and ser221 of subtilisin bpn'. significant features of th ...19938436946
survival of nonculturable aeromonas salmonicida in lake water.the survival of aeromonas salmonicida subsp. salmonicida was investigated in sterile and untreated lake water. in sterile lake water (filtered and autoclaved), it was found that cells of a. salmonicida entered a nonculturable but viable condition. viability was determined by flow cytometry with the dye rhodamine 123, which is taken up and maintained within cells with a membrane potential. for survival studies in untreated lake water, a. salmonicida was marked with the xyle gene by using the plas ...19938481011
non-culturable aeromonas salmonicida in lake water.the survival of aeromonas salmonicida subsp. salmonicida was investigated in lake water. during a 21-day study a. salmonicida became non-culturable in sterile lake water held at 10 degrees c. the incubation of replicate samples between 5 degrees c and 25 degrees c produced similar results. the recovery of colony-forming units of a. salmonicida from different lake water systems indicated that they survived longer in water that was naturally enriched (eutrophic) or enriched with tryptone soya brot ...19921342635
temperature-dependent in vitro antimicrobial activity of four 4-quinolones and oxytetracycline against bacteria pathogenic to fish.the in vitro antimicrobial activities of oxolinic acid, flumequine, sarafloxacin, enrofloxacin, and oxytetracycline against strains of bacteria pathogenic to fish (aeromonas salmonicida subsp. salmonicida, atypical a. salmonicida, vibrio salmonicida, vibrio anguillarum, and yersinia ruckeri) were determined at two different incubation temperatures, 4 and 15 degrees c, by a drug microdilution method. the main objective of the study was to examine the effect of incubation temperature on the in vit ...19921416857
survival of aeromonas salmonicida in lake water.the survival of aeromonas salmonicida subsp. salmonicida in lake water was investigated by using a variety of techniques. they included acridine orange epifluorescence, respiration, cell culture, cell revival, flow cytometry, plasmid maintenance, and membrane fatty acid analysis. during a 21-day study, a. salmonicida became nonculturable in sterile lake water samples. flow cytometry and direct microscopy indicated that cells were present. although the nonculturable cells could not be revived, th ...19911872606
evidence against dormancy in the bacterial fish pathogen aeromonas salmonicida subsp. salmonicida.results indicate that a. salmonicida does not enter an unculturable dormant state. the resuscitation of dormant cells by nutrient broth described by previous workers appears to be due to the presence of small numbers of viable, culturable cells too few to be detected by the sampling protocol employed.19902332152
isolation of aeromonas salmonicida from masu salmon in the republic of korea.the isolation and identification of the gram-negative fish pathogen, aeromonas salmonicida salmonicida, from masu salmon (oncorhynchus masou) at the yang yang salmon hatchery in the republic of korea is described. the bacterium possessed certain characteristics in common with isolates from fish in japan. it is an important cause of mortality among cultured salmonids in the republic of korea. this is the first report of this fish pathogen from the asian mainland.19883373645
structural studies on the o-antigen of aeromonas salmonicida.lipopolysaccharide from a strain of aeromonas salmonicida salmonicida was isolated from cells by the aqueous phenol method in 2.3% yield (based on dry weight of bacteria). hydrolysis of the lipopolysaccharide in 1% acetic acid afforded o-polysaccharide (19% by weight), core-oligosaccharide (12.2%) and lipid a (44.6%). analysis indicated that 3-deoxy-d-manno-2-octulosonic acid was absent from the lipopolysaccharide and that no low-molecular-weight compounds were released by the mild hydrolysis. t ...19836188611
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