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molecular and phenotypic methods for the characterization of atypical aeromonas salmonicida.atypical aeromonas salmonicida form a taxonomically diverse group among the psychrophilic a. salmonicida. characteristics of 53 atypical a. salmonicida strains originating from finland, denmark, norway and sweden were studied using 60 phenotypic tests. ribopattern analysis and plasmid profiles were used as genetic methods. the production of brown pigment on the furunculosis agar containing l-tyrosine divided the atypical oxidase-positive strains into two groups: pigment-producing (n = 35) and ac ...19979228690
purification and properties of an aminopeptidase from a protamine-degrading marine bacterium.a protamine-degrading marine bacterium was isolated from marine soil and identified as aeromonas salmonicida subsp. based on its taxonomical characteristics. an alanine-specific aminopeptidase, called aminopeptidase k, from an extract of the strain was purified and characterized. the aminopeptidase k was purified about 80-fold by fractionation with ammonium sulfate and column chromatography on qa-52 cellulose, phenyl superose and superose 12. the purified enzyme is composed of 6 subunits of 86 k ...19979255972
adjuvants and immunostimulants for enhancing vaccine potency in fish.adjuvants combined with immunogens are effective enhancers of the immune response in fish. as in other animals, substances such as freund's complete and incomplete adjuvants, light oils and bacterial lipopolysaccharides have been shown to induce elevated antibody production when added to bacterins and administered to fish. light oil adjuvants are now used successfully with injectable bacterins of aeromonas salmonicida, and in multivalent fish vaccines where a. salmonicida is combined with yersin ...19979270854
vaccinated fish welfare: protection versus side-effects.active immunisation of fish involves a number of potentially harmful procedures like handling, anaesthesia or injection of more or less toxic substances. adjuvanted vaccines may cause inflammation, granuloma and pigmentation at the site of injection. intraperitoneal administration of oil-adjuvanted vaccines to atlantic salmon pre-smolts has occasionally resulted in impaired growth and reduced carcass quality. the consequences of such vaccination for fish welfare may therefore be questioned. with ...19979270866
vaccination strategies in freshwater salmonid aquaculture.the focus of this chapter is antibacterial vaccines. the main salmonid species in freshwater aquaculture is the rainbow trout. other salmonid species are produced on a limited scale. the most important bacterial fish diseases in european freshwater aquaculture are the rainbow trout fry syndrome-rtfs-(flavobacterium psychrophilum) and enteric redmouth disease-erm-(yersinia ruckeri) which are widespread and cause serious epizootics, while furunculosis (aeromonas salmonicida) is endemic, only givin ...19979270868
functions of s-layers.although s-layers are being increasingly identified on bacteria and archaea, it is enigmatic that in most cases s-layer function continues to elude us. in a few instances, s-layers have been shown to be virulence factors on pathogens (e.g. campylobacter fetus ssp. fetus and aeromonas salmonicida), protective against bdellovibrio, a depository for surface-exposed enzymes (e.g. bacillus stearothermophilus), shape-determining agents (e.g. thermoproteus tenax) and nucleation factors for fine-grain m ...19979276929
quorum sensing in aeromonas hydrophila and aeromonas salmonicida: identification of the luxri homologs ahyri and asari and their cognate n-acylhomoserine lactone signal molecules.spent culture supernatants from both aeromonas hydrophila and aeromonas salmonicida activate a range of biosensors responsive to n-acylhomoserine lactones (ahls). the genes for a quorum sensing signal generator and a response regulator were cloned from each aeromonas species and termed ahyri and asari, respectively. protein sequence homology analysis places the gene products within the growing family of luxri homologs. ahyr and asar are transcribed divergently from ahyi and asai, respectively, a ...19979286976
identification and molecular characterization of two tandemly located flagellin genes from aeromonas salmonicida a449.two tandemly located flagellin genes, flaa and flab, with 79% nucleotide sequence identity were identified in aeromonas salmonicida a449. the fla genes are conserved in typical and atypical strains of a. salmonicida, and they display significant divergence at the nucleotide level from the fla genes of the motile species aeromonas hydrophila and aeromonas veronii biotype sobria. flaa and flab encode unprocessed flagellins with predicted mrs of 32,351 and 32,056, respectively. when cloned under th ...19979286979
the synthesis, secretion and role in virulence of the paracrystalline surface protein layers of aeromonas salmonicida and a. hydrophila.the s-layers of the aeromonas spp. studied to date are composed of identical protein subunits which are translocated across the cytoplasmic membrane, periplasm and outer membrane to the cell surface, where they are assembled and tethered to the cell via an interaction with the o-polysaccharide side chains of the lipopolysaccharide. aeromonas s-layers have the ability to bind a number of host factors such as fibronectin, laminin and vitronectin as well as providing resistance to serum killing and ...19979297815
aeromonas popoffii sp. nov., a mesophilic bacterium isolated from drinking water production plants and reservoirs.we examined the taxonomic position of seven aeromonas isolates, recovered from flemish and scottish drinking water production plants and reservoirs, which were previously recognized by numerical analysis of genomic aflp fingerprints as members of an unknown aeromonas taxon that most closely resembled the species aeromonas bestiarum (dna hybridization group [hg] 2). the new phenotypic and dna-dna hybridization data obtained in this study show that the a. bestiarum-like strains constitute a separa ...19979336924
pathogenicity of atypical aeromonas salmonicida in atlantic salmon compared with protease production.the pathogenicity of extracellular products (ecps) from 24 atypical aeromonas salmonicida strains was studied with respect to: lethality in atlantic salmon, pathogenic effect in muscle, haemolytic activity, cytotoxicity in two fish cell lines and proteolytic activities. furthermore, the relationship between lethality of ecps and mortality caused by bacterial challenge was examined. correlation was demonstrated between the pathogenic properties and proteolytic activities of the ecps. cytolytic (g ...19979418019
reappraisal of the effect of temperature on the growth kinetics of aeromonas salmonicida.the effect of temperature (1-34 degrees c) on the maximum specific growth rate of aeromonas salmonicida could not be described by the classical growth models; for some strains, two optimal temperatures at 23 degrees c and 30 degrees c were observed, as well as an unexpected increase in the pseudolag time above 27 degrees c. this could be explained by the presence of two subsets, notably s-layer+ and s-layer- sub-populations. the a- cells had higher growth parameters (topt and mu opt) than the a+ ...19979418073
further characterization of renibacterium salmoninarum extracellular products.renibacterium salmoninarum, the agent of bacterial kidney disease in salmonids, releases high concentrations of extracellular protein in tissues of infected fish. the extracellular protein consists almost entirely of a 57-kda protein and derivatives of degradation and aggregation of the same molecule. the 57-kda protein and its derivatives were fractionated into defined ranges of molecular mass. separated fractions continued to produce degradation and aggregation products. one-dimensional electr ...19979480644
acute phase proteins in salmonids: evolutionary analyses and acute phase response.inflammation induces dramatic changes in the biosynthetic profile of the liver, leading to increased serum concentrations of positive acute phase (ap) proteins and decreased concentrations of negative ap proteins. serum amyloid a (saa) and the pentraxins c-reactive protein (crp) and serum amyloid p component (sap) are major ap proteins: their serum levels can rise by 1000-fold, indicating that they play a critical role in defense and/or the restoration of homeostasis. we have cloned saa and a sa ...19978977214
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
the disulfide bond in the aeromonas hydrophila lipase/acyltransferase stabilizes the structure but is not required for secretion or activity.vibrio and aeromonas spp. secrete an unusual 35-kda lipase that shares several properties with mammalian lecithin-cholesterol acyltransferase. the aeromonas hydrophila lipase contains two cysteine residues that form an intramolecular disulfide bridge. here we show that changing either of the cysteines to serine does not reduce enzymatic activity, indicating that the disulfide bond is not required for correct folding. however, when either of the cysteines is replaced, the enzyme is more readily d ...19979150203
[recent knowledge on fish pathogenic bacteria aeromonas salmonicida, listonella anguillara and cytophaga columnaris, and their virulence factors]. 19979155200
proceedings: concurrent x-ray photodensitometric and gamma-ray absorptiometric measurements of bone mineral in the radius in patients. 1997179395
electron beam therapy in head and neck tumors.electron beam therapy with its high energy capabilities appears promising as a therapeutic modality in head and neck neoplasms. over a 10-year period, 153 cases of head and neck neoplasms involving the alveolar ridge, floor of mouth, buccal mucosa, retromolar trigone, tonsil, parotid, tongue, and pharynx were treated. the pharyngeal group was removed from consideration because of the unsuitability of this lesion for single port therapy. normal standard doses and time-dose fractions are included ...1997179392
fanconi's familial hypoplastic anaemia with some unusual features.a case of fanconi's familial hypoplastic anaemia is described in a 48-year-old woman who had the usual haematological and constitutional abnormalities of this condition. chromosomal studies on peripheral blood lymphocytes and direct marrow preparations demonstrated the chromosomal breaks previously described. the age of the patient and a congenital abnormality of breast development were unusual features, while the discovery of a benign liver tumour at necropsy is of interest, as the patient had ...1996177847
the effect of temperature and water quality on antibody response to aeromonas salmonicida in sunshine bass (morone chrysops x morone saxatilis).the kinetics of the antibody response to aeromonas salmonicida were determined in sunshine bass (hybrid striped bass: female morone chrysops x male morone saxatilis) acclimated to 10, 18, 24, 29 degrees c, and to 0.15 mg 1(-1) un-ionized ammonia and 200 mg 1(-1) nitrate levels. temperature and water quality factors affected the immune response of sunshine bass. temperatures of 10 degrees c and 18 degrees c decreased the magnitude and delayed the time of the antibody response to a. salmonicida. t ...19969157680
characterization of a stable l-form of the fish pathogen aeromonas salmonicida.a stable l-form of aeromonas salmonicida, which resulted from induction with benzylpenicillin, contained more of an outer membrane protein, with an estimated molecular weight of 40 kda but less of 47.9 and 38 kda proteins, than did parental walled cells. in addition, from western blots, two protein bands reacted strongly with a polyclonal antiserum. the antiserum did not react demonstrably with the band detected in the l-forms on the gels.19968987904
aeromonas salmonicida possesses two genes encoding homologs of the major outer membrane protein, ompa.two homologs of the outer membrane protein ompa were identified in aeromonas salmonicida by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and amino-terminal sequence analyses. an a. salmonicida genomic dna library was constructed by using lambda gem-11 and recombinant phage carrying both genes ompai and ompaii) selected by immunoscreening. a 5.0-kb bamhi fragment containing the two genes in tandem was subcloned in pbluescript and used for further subcloning and seque ...19968626290
immunotoxic effects of copper and cadmium in the sea bass dicentrarchus labrax.two phagocytes-mediated activities of the sea bass dicentrarchus labrax were examined after exposure to sublethal concentrations of copper and cadmium: (a) phagocytosis (measured by phagocytotic index), and (b) the production of reactive oxygen intermediates (luminol-dependent chemiluminescence) in response to bacteria aeromonas salmonicida. in vivo exposure for 48 h to each metal separately by intraperitoneal injection did not affect the quantity of phagocytes of pronephros and their viability ...19968683034
characterization of atypical aeromonas salmonicida isolates by ribotyping and plasmid profiling.a total of 38 strains of atypical aeromonas salmonicida, three oxidase-negative but otherwise typical aer. salmonicida, three typical aer. salmonicida, and two reference strains, isolated from several countries and fish species were examined with respect to rrna gene restriction patterns (ribotypes) and plasmid profiles. most epidemiologically unrelated strains had different ribotypes, whereas isolates from the same outbreak were identical. all strains, except one, carried one or more large plas ...19968698652
utilization of transferrin and salmon serum as sources of iron by typical and atypical strains of aeromonas salmonicida.the ability of typical and atypical strains of aeromonas salmonicida to utilize non-haem sources of protein-bound iron was evaluated. (i) in a plate bioassay, the suppression of growth imposed on typical and atypical a. salmonicida by addition of the high-affinity iron chelator ethylenediamine-di(o- hydroxyphenylacetic acid) (edda) to the growth medium was reversed by the addition of 30% or 90% iron-saturated bovine or human transferrin (tf) or lactoferrin (lf) to the growth medium. (ii) the mec ...19968704995
cloning and nucleotide sequence of the dna gyrase gyra gene from the fish pathogen aeromonas salmonicida.the dna gyrase gyra gene from the fish pathogen aeromonas salmonicida 2148/89 was cloned, and the nucleotide sequence was determined. an open reading frame of 2,766 nucleotides was identified and was found to encode a protein of 922 amino acids with a calculated molecular mass of 101.1 kda. the derived amino acid sequence shared a high degree of identity with other dna gyrase a proteins, in particular, with other gram-negative gyra sequences. when the amino acid sequence of a. salmonicida gyra w ...19968723452
a live (delta aroa) aeromonas salmonicida vaccine for furunculosis preferentially stimulates t-cell responses relative to b-cell responses in rainbow trout (oncorhynchus mykiss).we have previously described (l. m. vaughan, p. r. smith, and t. j. foster, infect. immun. 61:2172-2181, 1993) the construction of a kanamycin-resistant aromatic-dependent mutant of aeromonas salmonicida, the causative agent of furunculosis, and its use as a live vaccine. here we describe the construction of an unmarked aroa deletion mutant and examine the nature and magnitude of immune responses in rainbow trout (oncorhynchus mykiss) to this vaccine strain. good proliferative and antibody respo ...19968751940
atypical aeromonas salmonicida isolated from diseased turbot (scophtalmus maximus l.).atypical aeromonas salmonicida were isolated from 3 outbreaks of disease among farmed turbot (scophthalmus maximus l.) in 3 different farms, 1 from norway (n1) and 2 from denmark (dk1 and dk2). in all 3 cases, the incidence of disease and mortality was high and the main characteristic pathological finding was skin ulcers and septicaemia. the isolated bacteria were subjected to a thorough phenotypic and genotypic examination and comparison in the laboratory. all 3 isolates belonged to a. salmonic ...19968767692
multiple regulation of carp (cyprinus carpio l.) macrophages and neutrophilic granulocytes by serum factors: influence of infection with atypical aeromonas salmonicida.normal carp serum contains inhibitory and stimulatory factors for macrophage and neutrophilic granulocyte respiratory burst activity. as stimulatory factors were only effective in combination with phorbol myristate actetate (pma) activation, it is concluded that they are probably linked to protein kinase c activation. both the stimulatory and inhibitory factors are heat stable. macrophage- and neutrophilic granulocyte-enriched cell fractions from the pronephros of carp had high respiratory burst ...19968797288
survival of cells and dna of aeromonas salmonicida released into aquatic microcosms.the survival of the bacterial fish pathogen aeromonas salmonicida, and persistence of its dna, were monitored in aquatic microcosms using selective culture and most probable number pcr. bacterial cells and naked dna were released into natural non-sterile microcosms consisting of lake sediment overlayered with lake water. two different types of surface sediment were used. one was sandy in character, taken from the shoreline whilst the other was a littoral loamy surface mud. inoculated cells and n ...19968810058
the role of the capsular polysaccharide of aeromonas salmonicida in the adherence and invasion of fish cell lines.the ability of several aeromonas salmonicida strains grown under different conditions (capsulated and non-capsulated) to adhere to and invade two fish cell lines was compared. the level of adherence was slightly higher when the strains were grown under conditions promoting capsule formation than when the same strains were grown under conditions which did not promote capsule formation. however, the most significant difference among the wild-type strains grown under conditions promoting capsule fo ...19968810501
application of a modified disc diffusion technique to antimicrobial susceptibility testing of vibrio anguillarum and aeromonas salmonicida clinical isolates.two techniques for antimicrobial susceptibility testing of vibrio anguillarum and aeromonas salmonicida strains were compared. the first method was the reference test that determines minimal inhibitory concentrations (mic); the second was a modified diffusion test that measures the inhibitory concentrations in diffusion (icd) by carrying out the diffusion test with five discs of differing contents. icd measurement was not applicable for the susceptibility testing of oxytetracycline and sulfadime ...19968828130
an aeromonas salmonicida gene required for the establishment of infection in rainbow trout (oncorhynchus mykiss).the asob gene of aeromonas salmonicida is located approximately 9 kb downstream of the structural gene (vapa) for the surface layer (a-layer). the nucleotide sequence of asob was determined and found to encode a putative polytopic cytoplasmic membrane protein which exhibited homology to a number of bacterial transport proteins. allele exchange mutagenesis of asob resulted in a mutant (a449-d) which was avirulent when administered by bath immersion. however, when administered by intraperitoneal i ...19968917088
cloning, characterization and expression of the reca gene of aeromonas salmonicida.the aeromonas salmonicida a449 reca gene has been cloned, sequenced and expressed in vitro. the predicted amino acid sequence of a. salmonicida reca was determined and, when compared to other reca, was found to possess a number of domains identical to those characterized in escherichia coli reca. the a. salmonicida reca was mobilized into an e. coli reca mutant strain and was shown to allow increased survival in the presence of the chemical mutagen mms and after ultraviolet (uv) irradiation. the ...19968917089
the cell surface of aeromonas salmonicida determines in vitro survival in cultured brook trout (salvelinus fontinalis) peritoneal macrophages.aeromonas salmonicida strains phenotypically differing in their a-layer, lipopolysaccharide, and macrophage cytotoxicity were tested in vitro for survivability in brook trout (salvelinus fontinalis) serum with or without antibodies, and in vivo following intraperitoneal injection. the ability of brook trout peritoneal macrophages to phagocytize and kill the different phenotypes was investigated in an in vitro assay. the virulent strain, a. salmonicida 80204, which has the full complement of know ...19968971685
endogenous mutagenesis by an insertion sequence element identifies aeromonas salmonicida abca as an atp-binding cassette transport protein required for biogenesis of smooth lipopolysaccharide.analysis of an aeromonas salmonicida a layer-deficient/o polysaccharide-deficient mutant carrying a tn5 insertion in the structural gene for a protein (vapa) showed that the abca gene immediately downstream of vapa had been interrupted by the endogenous insertion sequence element isas1. immunoelectron microscopy showed that o polysaccharides did not accumulate at the inner membrane-cytoplasm interface of this mutant. abca encodes an unusual protein; it carries both an amino-terminal atp-binding ...19957777581
fatty acid profiles of "pasteurella" piscicida: comparison with other fish pathogenic gram-negative bacteria.the fatty acid methyl ester (fame) profiles of "pasteurella" piscicida were determined by gas chromatography and subjected to numerical analysis in comparison with those obtained for vibrio anguillarum, aeromonas salmonicida and pasteurella species of clinical origin. the bacterial species studied shared important characteristics with respect to their fame content: in all of them the saturated and unsaturated fatty acids of 16 carbon atoms were the predominant fatty acids. however, distinguishin ...19957778977
cloning and study of the genetic organization of the exe gene cluster of aeromonas salmonicida.the aeromonas salmonicida (as) exe gene cluster, an additional member of the pul-related operon family required for general signal-sequence-dependent secretion of proteins from gram- bacteria, was cloned in the broad-host-range cosmid plafr3. twelve genes, exec-n, were identified by partial nucleotide (nt) sequence analyses (exee-n) or determination of the complete sequence (exec and exed). the organisation of the exec-n genes is similar to that of several other operons of this family. these gen ...19957789814
development of a specific biotinylated dna probe for the detection of renibacterium salmoninarum.a specific dna probe for the identification of renibacterium salmoninarum, the causative agent of bacterial kidney disease (bkd), was developed from one of 3 clones prs47, prs49, and prs26 of 5.1 kb, 5.3 kb, and 11.3 kb, respectively. the biotinylated prs47/bamhi insert probe was tested on 3 dilutions of dna extracted from 3 strains of r. salmoninarum and from 1 strain each of arthrobacter protophormiae, aeromonas salmonicida, corynebacterium aquaticum, carnobacterium piscicola, listonella angui ...19958548693
study of the humoral response of atlantic salmon (salmo salar l.), naturally infected with aeromonas salmonicida ssp. achromogenes.the humoral antibody response of healthy atlantic salmon and of two groups of salmon, naturally infected with aeromonas salmonicida ssp. achromogenes, was examined in some detail. one diseased group was chronically infected and the other recently infected. it was found that the humoral response of these two infected groups was quite different. the chronically infected fish showed poor specific response to the causative agent whereas the recently infected salmon produced strong specific antibody ...19958588335
capsulated cells of aeromonas salmonicida grown in vitro have different functional properties than capsulated cells grown in vivo.when grown in vivo in the peritoneal cavity of rainbow trout, aeromonas salmonicida produces a clearly defined capsule with virulence-related functions. aeromonas salmonicida grown in vitro in a glucose-rich medium (grm) has also been reported to reproduce capsular material. because in vitro mimicry of in vivo induced traits is highly desirable in vaccine design, the extent to which growth in grm mimicked in vivo growth was examined. antibodies specific to in vivo grown cells partially labeled t ...19958590408
vibrio spp. secrete proaerolysin as a folded dimer without the need for disulphide bond formation.proaerolysin is an extracellular dimeric protein that is secreted across the inner and outer membranes of aeromonas spp. in separate steps. to investigate the role of protein folding in the second step, one or more cysteine residues were introduced and the mutant proaerolysins were expressed in aeromonas hydrophila and aeromonas salmonicida, as well as vibrio cholerae. replacing met-41 with cys resulted in expression of a protein that could form a dimer in which the monomers were linked together ...19958594324
immunoregulatory activities of eicosanoids in the rainbow trout (oncorhynchus mykiss).eicosanoids such as prostaglandins (pg), leukotrienes (lt) and lipoxins (lx) have been shown to be potent immunoregulatory molecules in mammals. to determine if they have similar roles in 'lower' animals, rainbow trout (oncorhynchus mykiss) were immunized with either sheep erythrocytes or aeromonas salmonicida in the presence or absence of the stable analogue of pge2, 16,16-dimethyl-pge2, and the number of plaque-forming cells (pfc) or specific antibody levels determined. the higher dose of 16,1 ...19957558126
the interaction of trimethoprim and quinolones against gram-negative fish pathogens.the effect of combination of trimethoprim with other non-sulphonamide antibacterial agents, in particular oxolinic acid and nalidixic acid, was evaluated against gram-negative fish pathogens. the species included aeromonas salmonicida, yersinia ruckeri, some vibrio spp. and escherichia coli as a reference. the extent of synergy found by other workers with these substances against human gram-negative bacteria was not apparent here. some positive interaction between trimethoprim and oxolinic acid ...19957592108
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
yeast beta-glucan stimulates respiratory burst activity of atlantic salmon (salmo salar l.) macrophages.previous studies have shown that head kidney macrophages isolated from glucan injected rainbow trout (oncorhychus mykiss) and atlantic salmon (salmo salar l.) have increased ability to kill aeromonas salmonicida. the present work was aimed at investigating the in vitro effects of glucan on the respiratory burst and bactericidal potential of atlantic salmon head kidney macrophages. salmon macrophages were incubated for 1-7 days with various concentrations of yeast beta-glucan (macrogard) and test ...19957615137
a conserved aeromonas salmonicida porin provides protective immunity to rainbow trout.a protein with an apparent m(r) of 28,000 was isolated from outer membrane preparations of aeromonas salmonicida a440. the protein was tested for the ability to form pores, using a planar lipid bilayer model membrane system. the protein appeared to be a monomer with a single-channel conductance in 1.0 m kcl of 1.96 ns and a cation/anion permeability ratio of 2.91 +/- 0.68. these data show that the porin channel is comparable in size to ompc and ompf of escherichia coli and is relatively nonselec ...19957622241
surface phenotypic characteristics and virulence of spanish isolates of aeromonas salmonicida after passage through fish.eleven strains of aeromonas salmonicida were passaged twice by intraperitoneal injection through rainbow trout and reisolated from the kidney of moribund fish. the surface characteristics and virulence of the strains changed following passage through fish. none of the in vitro tests used could effectively predict the in vivo virulence.19957646039
evaluation of the suitability of bis-(1,3-dibutylbarbituric acid) trimethine oxonol, (diba-c4(3)-), for the flow cytometric assessment of bacterial viability.the usefulness of oxonol (bis-(1,3-dibutylbarbituric acid)trimethine oxonol) as a generally applicable indicator of bacterial viability was investigated using untreated and killed cultures of a variety of bacterial genera. killing methods involved either heat or bactericidal antibiotics. for all strains tested, the fluorescent dye showed significantly more intense staining of killed than untreated cells. the sensitivity of aeromonas salmonicida to gentamicin was assessed using oxonol. although t ...19957649437
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
identification and characterization of the insertion element is1070 from leuconostoc lactis nz6009.a novel insertion sequence, designated is1070, was identified on the lactose plasmid of leuconostoc lactis nz6009 by nucleotide sequence analysis. the 1027-bp sequence contains partially matched (24 of 28 bp) inverted repeats and has one long open reading frame. the deduced 305-amino-acid sequence demonstrated homology to transposases of is30 from escherichia coli, is4351 from bacteroides fragilis, is1086 from alcaligenes eutrophus, is1161 from streptococcus salivarius, isas2 from aeromonas salm ...19957698675
ecopathology in aquaculture: risk factors in infectious disease outbreak.this paper describes a study of the risk factors associated with disease outbreaks in fish species of fish farms and rivers of north-east spain. we focused our work on the isolation of fish pathogens (bacteria, virus), the water quality (physicochemical and microbiological quality) and management characteristics. we have observed 2 important viral diseases, infectious pancreatic necrosis and spring viraemia of carp, and 2 important bacterial ones, furunculosis (aeromonas salmonicida) and bacteri ...19957711777
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
the plasmid profiles of fish pathogenic isolates of aeromonas salmonicida, vibrio anguillarum, and vibrio ordalii from the atlantic and pacific coasts of canada.the plasmid profiles of oxytetracycline- and streptomycin-resistant isolates of aeromonas salmonicida, vibrio anguillarum, and vibrio ordalii were examined by agarose gel electrophoresis. bacterial isolates were from disease outbreaks in fish on the atlantic and pacific coasts. resistant isolates were examined when grown in the presence and absence of antibiotic. alkaline lysis methods were used for plasmid isolation. vibrio spp. were predominantly plasmidless, except for a 47-kilobase (kb) plas ...19957736353
molecular analysis of an a-protein secretion mutant of aeromonas salmonicida reveals a surface layer-specific protein secretion pathway.the aeromonas salmonicida tn5 mutant, a449-tm1, is unable to secrete the surface layer protein (a-protein) through the outer membrane. immunogold labeling of thin sections of a449-tm1, with polyclonal antisera against the a-protein, showed the accumulation of large quantities of a-protein in an enlarged periplasm. the majority of the labeled a-protein could be seen at the poles of the cells. the ability of a449-tm1 to secrete other extracellular proteins such as hemolysin and protease was not im ...19957739043
physical and functional s-layer reconstitution in aeromonas salmonicida.the various functions attributed to the s-layer of aeromonas salmonicida have been previously identified by their conspicuous absence in s-layer-defective mutants. as a different approach to establish the multifunctional nature of this s-layer, we established methods for reconstitution of the s-layer of a. salmonicida. then we investigated the functional competence of the reconstituted s-layer. s-layers were reconstituted in different systems: on inert membranes or immobilized lipopolysaccharide ...19957751277
molecular characterization of an aeromonas salmonicida mutant with altered surface morphology and increased systemic virulence.the asoa gene of aeromonas salmonicida is located approximately 7 kb downstream of the a-layer structural gene, vapa. a 6 kb bamhi fragment containing asoa was cloned and marker-exchange mutagenesis using a kanamycin-resistance cassette was performed to generate an asoa mutation in the low-virulence strain a449l. when analysed by electron microscopy, the mutant a449l-mb exhibited an altered surface morphology. strands and blebs of membranous material were observed protruding from the disorganize ...19957752897
degradation of propanil by bacterial isolates and mixed populations from a pristine lake.the microbial transformation rates of propanil, a commonly used herbicide, were investigated using water from a pristine lake in northeast georgia. microbial degradation rates were measured using natural water microflora, the natural water microflora amended with five bacterial species (aerobacter aerogenes, aeromonas hydrophila, acinetobacter calcoaceticus, proteus mirabilis, and aeromonas salmonicida) isolated from the same lake, and the five isolates individually. transformation rate constant ...19957874462
recombinant infectious hematopoietic necrosis virus and viral hemorrhagic septicemia virus glycoprotein epitopes expressed in aeromonas salmonicida induce protective immunity in rainbow trout (oncorhynchus mykiss).fragments of the glycoprotein genes of viral hemorrhagic septicemia virus (vhsv) and infectious hematopoietic necrosis virus (ihnv) were cloned into a bacterial broad-host-range expression vector under the control of the plac promoter. western blot (immunoblot) analysis with monoclonal antibodies specific to the glycoproteins demonstrated the inducible expression of the fusion proteins in escherichia coli. aeromonas salmonicida is the causative agent of furunculosis in salmonid fish. it was conf ...19957486994
the leucine zipper of aeromonas salmonicida abca is required for the transcriptional activation of the p2 promoter of the surface-layer structural gene, vapa, in escherichia coli.the aeromonas salmonicida abca protein is involved in the synthesis of the o-polysaccharide side-chains on the lipopolysaccharide and is also capable of enhancing the expression of the structural gene for the a-layer, vapa, when cloned into escherichia coli. the p2 promoter of the vapa gene of a. salmonicida was cloned into a promoter probe vector and expression in e. coli was monitored. the expression of p2::lacz was shown to be increased when abca was provided in trans. abca contains an n-term ...19957494486
survival and activity of lux-marked aeromonas salmonicida in seawater.the fish pathogen aeromonas salmonicida was chromosomally marked with genes encoding bacterial luciferase, luxab, isolated from vibrio fischeri, resulting in constitutive luciferase production. during exponential growth in liquid batch culture, luminescence was directly proportional to biomass concentration, and luminometry provided a lower detection limit of approximately 10(sup3) cells ml(sup-1), 1 order of magnitude more sensitive than enzyme-linked immunosorbent assay detection. in sterile s ...199516535133
time vs. distance as measures of exposure in driving surveys.a survey of drivers carried out in ontario in 1988 has provided data on time spent driving as well as the distances driven for licensed drivers of both sexes in six age groups and three regions. substantial differences were found in times, distances, and distance/time ratios among these groups. men drove 50% greater distances, but spent only 30% more time driving than women; speed, averaged over each day's driving, was lower for older drivers than for younger drivers. differences in speed reflec ...19951388587
cardiac function in obstructive sleep apnea patients following uvulopalatopharyngoplasty.obstructive sleep apnea syndrome (osas) is associated with severe cardiac arrhythmias and conduction abnormalities. cor pulmonale and right-sided heart failure may ensue. uvulopalatopharyngoplasty (uppp) is one of several treatment modalities suggested for osas. tracheotomy and cpap treatment in adult osas patients and adenotonsillectomy in children with osas were shown to lead to improvement in some cardiac parameters. cardiac function was prospectively evaluated in 19 osas patients before and ...19951383911
microbial metabolism of aryl sulphonates a re-assessment of colorimetric methods for the determination of sulphite and their use in measuring desulphonation of aryl and alkylbenzene sulphonates.the reaction of 2,4-dinitroanilinomaleimide with sulphite which has been claimed as the basis of a suitable colorimetric assay for the anion was carefully re-examined. the sulphite-imide addition product provides a suitable and specific qualitative test for sulphite after separation by paper chromatography but the method as previously used is probably measuring the hydrolysis of the imide to 2,4-dinitroanilinomaleamic acid and cannot be used for sulphite determination either colorimetrically or ...1995176938
a survey of asthma mortality in patients between ages 35 and 64 in the greater london hospitals in 1971.we have examined the death certificates from all patients aged 35-64 years who were recorded as dying from asthma in greater london council hospitals in 1971. of the 47 death certificates studied, nine suggested that the primary cause of death was not asthma. from the remaining 38 deaths we have obtained 36 case records and found that 15 deaths occurred outside hospital and another two patients died in hospital having been admitted in a stable state. we have examined the remaining 19 case record ...1995167466
dormant/unculturable cells of the fish pathogen aeromonas salmonicida.viable cells of aeromonas salmonicida remained in experimental marine systems after plate counts indicated an absence of culturable cells. these so-called viable but nonculturable (vbnc) cells were coccoid and smaller than their normal culturable counterparts. there was no reduction in lipopolysaccharide of the vbnc cells. there was an alteration in protein composition, however, with a decline in some (15, 70, 30, 22, and 17 kda), but an increase in another protein (49 kda). a significant loss o ...199524185484
the effect of dietary vitamin a on the immunocompetence of atlantic salmon (salmo salar l.).atlantic salmon, salmo salar l. were maintained on diets containing low (0.37 mg kg(-1) diet), normal (1.95 mg kg(-1) diet) and high (15 mg kg(-1) diet) levels of vitamin a fed at 1.5% body weight per day. after 4 months, liver vitamin a levels reflected dietary intake and growth rates of all three groups were similar. kidney leucocyte migration and serum bactericidal activity were found to be significantly reduced in fish fed low levels of vitamin a. on the other hand, high levels of vitamin a ...199424203112
effect of beta1-24-corticotropic hormone, angiotensin ii and xanthinol nicotinate on the kinetics of aldosterone. 1994201974
serum ferritin in pregnancy: the effect of iron supplementation. 1994284763
effect of electroconvulsive therapy (electroshock) on plasma acth, gh, lh, fsh, tsh and 11-oh-cs in patients with mental disorders. 1994201900
specific dna probes for the identification of the fish pathogen, renibacterium salmoninarum.to obtain specific dna probes for the identification of the fish pathogen, renibacterium salmoninarum, a discriminatory recombinant dna library was constructed using selective fragments of the bacterial genome. three renibacterial clones, pmam29, pmam46 and pmam77, containing 149, 73, and 154 bp respectively, were isolated and characterized. the specificity of the probes was confirmed by dot-blot and southern hybridization analyses. bacterial hybridization experiments revealed that pmam29 discri ...199424420936
siderophore-mediated iron sequestering by shewanella putrefaciens.the iron-sequestering abilities of 51 strains of shewanella putrefaciens isolated from different sources (fish, water, and warm-blooded animals) were assessed. thirty strains (60%) produced siderophores in heat-sterilized fish juice as determined by the chrome-azurol-s assay. all cultures were negative for the catechol-type siderophore, whereas 24 of the 30 siderophore-producing strains tested positive in the csáky test, indicating the production of siderophores of the hydroxamate type. sideroph ...199416349298
transfer in marine sediments of the naturally occurring plasmid pras1 encoding multiple antibiotic resistance.the results of microcosm experiments performed with the fish-pathogenic bacterium aeromonas salmonicida acting as a donor showed that promiscuous plasmid pras1, which encodes tetracycline resistance, is transferred at a high frequency in marine sediments even in the absence of a selective factor. the presence of oxytetracycline resulted in an increase in the transfer frequency compared with that of a microcosm to which no selective factor was added. transfer frequencies of 3.4 x 10 transconjugan ...199416349453
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
assessing glycosidic linkage flexibility: conformational analysis of the repeating trisaccharide unit of aeromonas salmonicida.a detailed conformational analysis was performed for the synthetic branched trisaccharide beta-d-mannac-(1-->4)-[alpha-d-glc-(1-->3)]-l-rha 1 which represents the repeating unit of the o-antigenic polysaccharide of aeromonas salmonicida. the study was based on 26 experimental noe curves from 1d transient noe experiments, employing gaussian-shaped inversion pulses at 600 mhz. eight of the noe curves were interglycosidic and thus useful for an analysis of glycosidic linkage orientations. metropoli ...19947510557
immunoregulation in fish. i: intramolecular-induced suppression of antibody responses to haptenated protein antigens studied in atlantic salmon (salmo salar l).we report here evidence for intramolecular-induced suppression of the in vivo antibody response in fish, using a panel of t-dependent hapten-carrier antigens. atlantic salmon were immunized intraperitoneally with protein antigens (limulus polyphemus hemocyanin, chicken gamma globulin, and aeromonas salmonicida a-layer protein) given in their native form or haptenated with either 4-hydroxy-3-iodo-5-nitrophenyl-acetic acid (nip), 2,4,6-trinitrophenyl-acetic acid (tnp), or fluorescein-5-iso-thiocya ...19947521853
phagocytic defence mechanism in sea bass (dicentrarchus labrax l.): an ultrastructural study.the ultrastructure of the phagocytic process in fish has not been established in spite of the significant morphofunctional differences detected in the fish immune system with respect to the basic immunological pattern in vertebrates. we report the ultrastructure of the bacterial phagocytic defence mechanism in sea bass (dicentrarchus labrax l.).19947879910
three beta-lactamases isolated from aeromonas salmonicida, including a carbapenemase not detectable by conventional methods.the beta-lactamases of seven strains of aeromonas salmonicida subsp. achromogenes resistant to amoxicillin (mic > 1024 mg/l) and responsible for furunculosis in farmed atlantic salmon in scotland were examined to establish the mechanisms of beta-lactam resistance. separation of a cell-free extract on an isoelectric focusing gel stained with the chromogenic cephalosporin nitrocefin showed the presence of two beta-lactamases, one with a pi of 7.9 and the other with a pi of 6.0. hydrolysis assays o ...19947889949
physiological consequences of the s-layer of aeromonas salmonicida in relation to growth, temperature, and outer membrane permeation.s-layers are paracrystalline protein multimers that cover the entire cell surface of many bacterial species. the presence of an s-layer in aeromonas salmonicida (also known as a-layer) predisposed this bacterium to apparently unrelated physiological consequences: inhibition of growth at 30 degrees c, enhanced cell filamentation at 37 degrees c, and enhanced uptake of the hydrophobic antibiotics streptonigrin and chloramphenicol. growth inhibition or enhanced filamentation was not observed when t ...19947922885
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
isolation of aeromonas salmonicida from paddlefish, polyodon spathula.aeromonas salmonicida was isolated from paddlefish (polyodon spathula) mortalities collected during an epizootic of furunculosis at the spring river state hatchery, arkansas (usa), in 1992. isolates of the bacterium were obtained from culture of gill and kidney tissue. this is the first epizootic of bacterial etiology to be reported in paddlefish.19947933294
genetic variation in the humoral immune response in atlantic salmon (salmo salar) against aeromonas salmonicida a-layer.antibody responses to aeromonas salmonicida a-layer were analysed in family material of atlantic salmon (salmo salar), consisting of 791 fish belonging to 34 full-sib groups within 12 paternal half-sib groups. the fish were immunized twice and blood samples were collected three times. significant increase in antibody titre from first to second, and from second to third sampling, was observed. genetic variation in antibody titres was observed at the three samplings with estimated heritabilities r ...19947941312
modulation of the bacterial clearance activity of haemocytes from the freshwater mollusc, lymnaea stagnalis, by the avian schistosome, trichobilharzia ocellata.the ability of haemocytes, from the haemolymph of the gastropod mollusc lymnaea stagnalis, to recognize and eliminate the bacterium aeromonas salmonicida was shown using an in vitro bacterial clearance assay. the assay employs a dye which is reduced by a. salmonicida in direct proportion to the number of viable bacteria resulting in a colour change which can be determined spectrophotometrically. addition of cytochalasin b resulted in a marked decrease in bacterial clearance, implicating both int ...19947970887
antigen-induced release of macrophage activating factor from rainbow trout oncorhynchus mykiss leucocytes.the production of macrophage-activating factor (maf) by rainbow trout, oncorhynchus mykiss, head kidney leucocytes at varying times post-immunisation, with the fish bacterial pathogen, aeromonas salmonicida, was investigated and correlated with head kidney lymphocyte proliferation and serum antibody production. maf production was preceded by lymphocyte proliferation and both responses were highest using whole bacterial cells as the in vitro stimulant. maf production and antibody production incre ...19947975191
atypical aeromonas salmonicida isolated from ulcerated chub leuciscus cephalis. 19947992477
characteristics of 'atypical', cytochrome oxidase-negative aeromonas salmonicida isolated from ulcerated flounders (platichthys flesus (l.)).'atypical', cytochrome oxidase-negative variants of the fish pathogen aeromonas salmonicida, isolated from ulcerated flounder (platichthys flesus), were studied using different methods. two of the strains possessed a protein that corresponded to the a-layer protein of aer. salmonicida. the strains reacted with antibodies against the a-layer and monoclonal antibodies against the o-antigen of typical aer. salmonicida. these tests confirm that the isolates from flounder should be classified as aer. ...19948005836
dietary intake of immunostimulants by rainbow trout affects non-specific immunity and protection against furunculosis.immunostimulant preparations macrogard, candida utilis, saccharomyces cerevisiae, evetsel, chitosan, or finnstim were mixed into semipurified diets and fed to groups of rainbow trout for 1 week. fish were bled by non-lethal caudal puncture and blood samples assayed for changes in non-specific cellular immunity and humoral protein levels. in the immunostimulated fish, hematocrit levels and lymphocyte counts remained relatively stable; however, elevations were observed in oxidative radical release ...19948066989
relationship between resistance of salmonids to furunculosis and recovery of aeromonas salmonicida from external mucus.fish were sampled at the ed weed state fish hatchery (south hero, vermont, usa) in september 1992. aeromonas salmonicida was common, with concentrations as high as 10(5) to 10(7) colony-forming units per gram of mucus, and readily recovered from most mucus samples obtained from furunculosis-sensitive populations of brook trout (salvelinus fontinalis), lake trout (salvelinus namaycush), and atlantic salmon (salmo salar). the pathogen was the predominant microorganism and accounted for greater tha ...19947760494
genetic variation in the humoral immune response against vibrio salmonicida and in antibody titre against vibrio anguillarum and total igm in atlantic salmon (salmo salar).total igm level and antibody titre to vibrio anguillarum o-antigen after bath-vaccination, and specific antibody response to v. salmonicida o-antigen at three different samplings were analysed in family material of atlantic salmon (salmo salar), consisting of 791 fish belonging to 34 maternal full-sib groups within 12 paternal half-sib groups. the fish were immunized twice, and blood samples collected three times. after the third blood sampling, the fish were challenged with v. anguillarum. medi ...19947725631
aeromonas salmonicida resistance to complement-mediated killing.the resistance of aeromonas salmonicida to complement-mediated killing was investigated by using different strains and their isogenic mutants that had been previously characterized for their surface components. we found that the classical complement pathway is involved in serum killing of susceptible a. salmonicida strains, while the alternative complement pathway seems not to be involved. all of the a. salmonicida strains are able to activate complement, but the smooth strains (with or without ...19947525485
detection of aeromonas salmonicida, causal agent of furunculosis in salmonid fish, from the tank effluent of hatchery-reared atlantic salmon smolts.the fish pathogen, aeromonas salmonicida, could be detected only by bacteriological culture from the kidney of dead or moribund fish in one tank in a hatchery rearing atlantic salmon (salmo salar l.) smolts. however, by using a dna probe specific for this species, allied to a pcr assay, the pathogen could be detected in water, feces and effluent samples taken from this fish tank. also, the presence of the pathogen was found in effluent samples from two fish tanks containing apparently healthy fi ...19947527205
gyra mutations in quinolone-resistant isolates of the fish pathogen aeromonas salmonicida.gyra mutations in quinolone-resistant isolates of aeromonas salmonicida have been detected by using pcr to amplify the quinolone resistance-determining region of gyra and subsequent cloning and sequencing of pcr products. comparison of nucleotide and derived amino acid sequences of pcr products from quinolone-susceptible and -resistant bacteria revealed a serine 83-to-isoleucine substitution in the gyrase a protein of resistant isolates. one of the resistant isolates differed from the other by a ...19947840589
mutagenesis of the paracrystalline surface protein array of aeromonas salmonicida by endogenous insertion elements.the tetragonal paracrystalline surface protein array (a-layer) of the fish pathogenic bacterium aeromonas salmonicida is a virulence factor and bacteria which are unable to produce a-layer are attenuated in their ability to kill fish. ten independent mutants of aeromonas salmonicida which were unable to produce a-layer were isolated by growth at 30 degrees c. these mutants displayed either reduced synthesis of the a-layer subunit, synthesis of a truncated subunit, or complete loss of the ability ...19948151705
biological markers of macrophage activation: applications for fish phagocytes.the immune defence mechanisms of fish seem to be related and similarly competent to those of mammals. because of this, there is an increased interest in the immune responses of fish as models for higher vertebrates in immunological/immunotoxicological studies. macrophages (m phi), phagocytic cells of the mammalian and teleost immune system which reside in tissues, represent a quiescent population of cells. however, upon stimulation, alterations in the physiology of these resident m phi occur whi ...19938244466
fate of the fish pathogen aeromonas salmonicida in the peritoneal cavity of rainbow trout.a model was developed to study the fate of the fish pathogen aeromonas salmonicida in vivo, inside a specialized intraperitoneal chamber implanted in rainbow trout, oncorhynchus mykiss. although normally recalcitrant to lytic agents in vitro, owing to the presence of its regular surface array (s layer), a. salmonicida was rapidly killed in the peritoneal cavity by a host-derived, soluble lytic activity present in peritoneal fluid. peritoneal fluid was also found to kill other bacteria and lyse v ...19938306206
cloning and characterization of three hemolysin genes from aeromonas salmonicida.two hemolysin genes (ash3 and ash4) of aeromonas salmonicida strain 17-2 and one (ash1) of a. salmonicida atcc14174 were cloned into the cosmid vector charomid 9-36 in escherichia coli dh1. the overall amino acid sequence of the ash3 was similar to that of the aerolysins of aeromonas hydrophila and aeromonas sobria, and hemolysins ahh3, ahh4, and ahh5 of a. hydrophila, and hemolysin asa1 of a. sobria. the sequence of ash4 was similar to that of the ahh1 hemolysin of a. hydrophila. the ash4 hemol ...19938309354
assessment of the antimicrobial sensitivity of aeromonas salmonicida isolates from farmed atlantic salmon in scotland.sixty-five isolates of aeromonas salmonicida were assessed for antimicrobial sensitivity by disc diffusion tests and the results compared with the minimum inhibitory concentration for each isolate. the results demonstrated that disc diffusion, using a standard technique, may be used to categorize isolates as sensitive or resistant provided that the corresponding minimum inhibitory concentrations are known.19938310605
the effect of iron limitation on the growth of aeromonas salmonicida.the effects of the iron-chelating agents ethylenediamine dihydroxyphenylacetic acid (edda), 2,2'-dipyridyl (dipy) and 8-hydroxyquinoline (8hq) on the growth of aeromonas salmonicida were examined. in these studies, edda caused a small decrease in growth, whereas dipy and 8hq reduced cell growth by 50 and 90%, respectively. the extracellular products contained a greater proportion of the major protease (70 kd) when cells were grown in the presence of the chelating agents. analysis of the outer me ...19938336555
host range and transfer efficiency of incompatibility group hi plasmids.hi plasmids are distinguished by their thermosensitive mode of conjugation (transfer efficiency is optimal at 22-30 degrees c) and their capacity to encode multiple antibiotic resistance. these traits have implicated hi plasmids as potential vectors in the dissemination of antibiotic resistance among pathogenic and indigenous bacterial species in water and soil environments. we compared the transfer efficiency of hi plasmids with that of plasmids from 13 other incompatibility groups at 37, 24, a ...19938358670
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