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PubMed1995

A specific oligonucleotide probe based on 5S rRNA sequences for identification of Vibrio anguillarum and Vibrio ordalii.

An oligonucleotide DNA probe based on 5S rRNA sequence data was constructed for the identification of the fish pathogens, Vibrio anguillarum and Vibrio ordalii. Specificity of the probe was tested in a colony blot hybridization assay. The respective probe was found to be specific for both V. anguillarum and V. ordalii. No cross hybridization was observed against other fish pathogens and the closely related Vibrionaceae genera. This specific probe may be useful for rapid identification of V. anguillarum and V. ordalii.

Base Sequence↗
PubMed2003

Analysis of the Vibrio pathogenicity island-encoded Mop protein suggests a pleiotropic role in the virulence of epidemic Vibrio cholerae.

Epidemic Vibrio cholerae contain a large essential virulence gene cluster called the Vibrio pathogenicity island (VPI). We recently reported that no in vitro difference in virulence was found in El Tor strain N16961 containing a mutation in the VPI-encoded mop gene but this mutant was hypervirulent and reactogenic in rabbit ileal loops. In this paper, we report in vitro studies showing that independent Mop mutants of strain 3083 are significantly attenuated (approximately 40-fold) in cholera toxin (CT) production and have significantly increased motility and biofilm forming ability but appear to be unaffected in TcpA, hemagglutinin protease and hemolysin compared to their parent. The 3083 Mop mutant showed a 100-fold decrease in its in vivo intestinal colonization ability in the infant mouse competition assays. While reverse transcription polymerase chain reaction and phenotypic studies of a mop plasmid in both mutant and wild-type backgrounds suggest Mop is expressed by the plasmid, the differences in CT and biofilm formation could not be restored in any of the mutants. The inability to complement the Mop mutants in trans may be due either to the selection of secondary mutations or to mop possibly being part of an operon. Our findings that Mop is associated with CT, motility, biofilm formation and intestinal colonization support a hypothesis in which Mop has a pleiotropic role in the pathogenesis and persistence of epidemic V. cholerae.

Animals↗
PubMed2003

Cloning and molecular characterization of a unique hemolysin gene of Vibrio pommerensis sp. nov.: development of a DNA probe for the detection of the hemolysin gene and its use in identification of related Vibrio spp. from the Baltic Sea.

A group of hemolytic Vibrio strains was isolated from surface water of the Baltic Sea in 1995. A typical representative strain, CH-291, was found to lyse washed human and animal erythrocytes. Hemolysis was found to be calcium-dependent and occurred over a temperature range from 25 to 37 degrees C. The hemolysin-encoding genes were identified by screening a genomic library of total DNA from strain CH-291. A cloned chromosomal DNA fragment of 15.6 kb conferred to Escherichia coli DH5alpha a hemolytic phenotype. Hybridization and sequence analysis showed the cloned sequence to be unique to these Baltic Sea Vibrio isolates and therefore provides a useful marker for their identification. Moreover, the cloned 15.6-kb DNA fragment possessed structural features typical for genetic islands, including a decreased GC content and a flanking cryptic insertion sequence element.

Baltic States↗
PubMed1984

Transferable plasmid-mediated drug resistance among non-O1 Vibrio cholerae and rough strains of Vibrio cholerae from Tamilnadu, India.

A total of 289 non-O1 Vibrio cholerae (NVC) strains and 20 rough V. cholerae (RVC) strains isolated in an endemic area were tested for antibiotic resistance and for transferable R-plasmids. Twenty three per cent of NVC and 40% of the RVC isolates were found to be resistant to one or more drugs. Eight NVC and four RVC strains possessed multiple drug resistance, varying from four to eight drugs. The common spectrum found in NVC isolates were chloramphenicol and streptomycin (CS) or chloramphenicol, streptomycin, tetracycline and ampicillin (CSTA). Resistance to sulphamethoxazole (Su) and to trimethoprim (Tm) was encountered infrequently. In RVC isolates in addition CSTASuTm determinants, resistance markers to aminoglycosides kanamycin, gentamicin and neomycin were also found. Eighteen of the 27 V. cholerae strains with two or more resistance determinants transferred them en bloc to Escherichia coli K12. The level of resistance in the recipient strain was equal to or greater than that of the donor vibrio strains. Most of the strains possessing solitary resistance markers were unable to transfer them. beta-lactamase production could be demonstrated in 92.8% of the ampicillin resistant strains. None of the strains was resistant to nalidixic acid or furazolidone. The results emphasize the importance of antimicrobic susceptibility determination of V. cholerae isolates, regardless of the serotypes, before commencing chemotherapy.

Anti-Bacterial Agents↗
PubMed2004

Reaction mechanism of chitobiose phosphorylase from Vibrio proteolyticus: identification of family 36 glycosyltransferase in Vibrio.

A family 36 glycosyltransferase gene was cloned from Vibrio proteolyticus. The deduced amino acid sequence showed a high degree of identity with ChBP (chitobiose phosphorylase) from another species, Vibrio furnissii. The recombinant enzyme catalysed the reversible phosphorolysis of (GlcNAc)2 (chitobiose) to form 2-acetamide-2-deoxy-alpha-D-glucose 1-phosphate [GlcNAc-1-P] and GlcNAc, but showed no activity on cellobiose, indicating that the enzyme was ChBP, not cellobiose phosphorylase. In the synthetic reaction, the ChBP was active with alpha-D-glucose 1-phosphate as the donor substrate as well as GlcNAc-1-P to produce beta-D-glucosyl-(1-->4)-2-acetamide-2-deoxy-D-glucose with GlcNAc as the acceptor substrate. The enzyme allowed aryl-beta-glycosides of GlcNAc as the acceptor substrate with 10-20% activities of GlcNAc. Kinetic parameters of (GlcNAc)2 in the phosphorolysis and GlcNAc-1-P in the synthetic reaction were determined as follows: phosphorolysis, k(0)=5.5 s(-1), K(m)=2.0 mM; synthetic reaction, k(0)=10 s(-1), K(m)=14 mM, respectively. The mechanism of the phosphorolytic reaction followed a sequential Bi Bi mechanism, as frequently observed with cellobiose phosphorylases. Substrate inhibition by GlcNAc was observed in the synthetic reaction. The enzyme was considered a unique biocatalyst for glycosidation.

Amino Acid Sequence↗
PubMed1993

N-3-hydroxypropionyl-alpha-D-perosamine homopolymer constituting the O-chain of lipopolysaccharides from Vibrio bioserogroup 1875 possessing antigenic factor(s) in common with O1 Vibrio cholerae.

A structural study was performed by 13C-n.m.r. spectroscopy and methylation analysis of the O-chain of lipopolysaccharide (LPS) from Vibrio bioserogroup 1875 possessing antigenic factor(s) in common with O1 Vibrio cholerae. It was demonstrated to contain a linear homopolymer of (1-->2)-linked N-3-hydroxypropionyl-alpha-D-perosamine [4-(3-hydroxypropanamido)-4,6-dideoxy-alpha-D-mannopyranose], which is very similar to, but not identical with, both (1-->2)-linked linear N-3-deoxy-L-glycero-tetronyl(S-2,4-dihydroxybutyryl)-alpha-D - perosamine homopolymer and (1-->2)-linked linear N-acetyl-alpha-D-perosamine homopolymer which constitute the O-chains of O1 V. cholerae and non-O1 V. cholerae bioserogroup Hakata LPS respectively.

Acetylation↗
PubMed2002

Entry of Vibrio harveyi and Vibrio fischeri into the viable but nonculturable state.

AIMS: Physiological responses of marine luminous bacteria, Vibrio harveyi (ATCC 14216) and V. fischeri (UM1373) to nutrient-limited normal strength (35 ppt iso-osmolarity) and low (10 ppt hypo-osmolarity) salinity conditions were determined. METHODS AND RESULTS: Plate counts, direct viable counts, actively respiring cell counts, nucleoid-containing cell counts, and total counts were determined. Vibrio harveyi incubated at 22 degrees C in nutrient-limited artificial seawater (ASW) became nonculturable after approximately 62 and 45 d in microcosms of 35 ppt and 10 ppt ASW, respectively. In contrast, V. fischeri became nonculturable at approximately 55 and 31 d in similar microcosms. Recovery of both culturability and luminescence of cells in the viable but nonculturable state was achieved by addition of nutrient broth or nutrient broth supplemented with a carbon source, including luminescence-stimulating compounds. Temperature upshift from 22 degrees C to 30 degrees C or 37 degrees C did not result in recovery from nonculturability. CONCLUSIONS: The study confirms entry of V. harveyi and V. fischeri into the viable but nonculturable state under low-nutrient conditions and demonstrates nutrient-dependent resuscitation from this state. SIGNIFICANCE AND IMPACT OF THE STUDY: This study confirms loss of luminescence of V. harveyi and V. fischeri on entry into the viable but nonculturable state and suggests that enumeration of luminescent cells in water samples may be a rapid method to deduce the nutrient status of a water sample.

Colony Count, Microbial↗
PubMed1997

Characterization of hapR, a positive regulator of the Vibrio cholerae HA/protease gene hap, and its identification as a functional homologue of the Vibrio harveyi luxR gene.

The Vibrio cholerae HA/protease gene (hap) promoter is inactive in Escherichia coli. We cloned and sequenced the 0.7kb hap promoter fragment from strain 3083-2 and showed that hap is located immediately 3' of ompW, encoding a minor outer membrane protein. A clone from a genomic library of strain 3083-2 was isolated, which was required for activation of the hap promoter in E. coli. Expression from the hap promoter only occurred late in the growth phase. A single complete open reading frame (ORF) designated HapR was identified on a 1.7 kb DNA fragment that was required for activation. Allelic replacements showed that hapR was also essential for hap expression in V. cholerae. In El Tor, but not in classical biotypes of V. cholerae, hapR mutations also produced a rugose colonial phenotype. HapR was shown to encode a 203-amino-acid polypeptide with 71% identity to LuxR of V. harveyi, an essential positive regulator of the lux operon that has no previously identified homologues. The amino-terminal domain (residues 21-68) showed significant homology to the TetR family of helix-turn-helix DNA-binding domains and was 95% identical to the same domain of LuxR. HapR and LuxR activated both the hap and the lux promoters at near wild-type levels, despite only limited homology in the promoter sequences (46% identity with 12 gaps over 420bp). DNA sequences and ORFs 5' (but not 3') of the hapR and luxR loci were homologous, suggesting a common origin for these loci, and hapR-hybridizing sequences were found in other vibrios. We conclude that HapR is absolutely required for hap expression and that HapR and LuxR form a new family of transcriptional activator proteins.

Amino Acid Sequence↗
PubMed2000

Anaerobic respiratory growth of Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi with trimethylamine N-oxide, nitrate and fumarate: ecological implications.

Two symbiotic species, Photobacterium leiognathi and Vibrio fischeri, and one non-symbiotic species, Vibrio harveyi, of the Vibrionaceae were tested for their ability to grow by anaerobic respiration on various electron acceptors, including trimethylamine N-oxide (TMAO) and dimethylsulphoxide (DMSO), compounds common in the marine environment. Each species was able to grow anaerobically with TMAO, nitrate or fumarate, but not with DMSO, as an electron acceptor. Cell growth under microaerophilic growth conditions resulted in elevated levels of TMAO reductase, nitrate reductase and fumarate reductase activity in each strain, whereas growth in the presence of the respective substrate for each enzyme further elevated enzyme activity. TMAO reductase specific activity was the highest of all the reductases. Interestingly, the bacteria-colonized light organs from the two squids, Euprymna scolopes and Euprymna morsei, and the light organ of the ponyfish, Leiognathus equus, also had high levels of TMAO reductase enzyme activity, in contrast to non-symbiotic tissues. The ability of these bacterial symbionts to support cell growth by respiration with TMAO may conceivably eliminate the competition for oxygen needed for both bioluminescence and metabolism.

Anaerobiosis↗
PubMed1999

Cloning and characterization of manganese superoxide dismutase gene from Vibrio parahaemolyticus and application to preliminary identification of Vibrio strains.

The sodA gene coding for manganese superoxide dismutase (Mn-SOD) from the marine microorganism Vibrio parahaemolyticus was cloned, sequenced, and overexpressed in Escherichia coli by use of the pET20b (+) expression vector. The full-length gene consisted of a 588-bp open reading frame and encoded a polypeptide of 196 amino acid residues, with a calculated molecular mass of 21,713 Da. The recombinant enzyme was efficiently purified from crude E. coli cell lysate by metal ion affinity chromatography. The recombinant VPMn-SOD resisted thermo-denaturation up to 60 degrees C and was insensitive to such inhibitors as EDTA, NaN3 and diethyldithiocarbamic acid. The specificity of V. parahaemolyticus Mn-SOD gene probe was analyzed by cross-species polymerase chain reaction to provide information for Vibrio strain identification.

Amino Acid Sequence↗
PubMed1993

Vibrio infections on the Gulf Coast: results of first year of regional surveillance. Gulf Coast Vibrio Working Group.

In 1989, the first year of coordinated Vibrio surveillance in four Gulf Coast states (Alabama, Florida, Louisiana, and Texas), 121 infections were reported. These included 34 V. parahaemolyticus, 30 V. cholerae non-O1, 18 V. vulnificus, 9 V. hollisae, 7 V. alginolyticus, and 7 V. fluvialis. Fourteen patients had primary septicemia, 71 had gastroenteritis, and 29 had wound infections; 7 had other or unknown illnesses. Sixty-six patients were hospitalized, and 9 died. All patients with primary septicemia, but only 17% of those with gastroenteritis, were known to have an underlying illness (P < .001). Among patients for whom data were available, 67% with primary septicemia and 74% with gastroenteritis ate raw oysters in the week before illness began. Of 50 patients with data on where oysters were obtained, 42 (84%) ate them at oyster bars or restaurants. These data provide evidence that in the Gulf Coast region raw oyster consumption is an important cause of Vibrio-associated gastroenteritis among adults without underlying illnesses.

Adolescent↗
PubMed2006

Freshwater bioluminescence in Vibrio albensis (Vibrio cholerae biovar albensis) NCIMB 41 is caused by a two-nucleotide deletion in luxO.

We previously proposed that the function of the lux operon is to produce a halotolerant flavodoxin, FP390 or P-flavin binding protein, and not to produce light. A crucial basis of this hypothesis is that almost all species of luminous bacteria emit light in culture media containing over 2% NaCl. However, Vibrio albensis (Vibrio cholerae biovar albensis) NCIMB 41 emits light in freshwater and this appears to be in direct conflict with our hypothesis. To determine why this exceptional freshwater bioluminescence is emitted, we studied the lux operon and the regulatory system of the operon in this strain, and found that expression of the operon is regulated by a system involving a derivative of 4,5-dihydroxy 2,3-pentanedione, DPD, as an inducer, and the repressor gene for the lux operon, luxO, is damaged by deletion of two nucleotides. Furthermore, to study the effect of damage to the luxO gene, pUC18 derivatives containing the damaged and repaired luxO sequences were prepared. Cells transfected with the damaged luxO sequence emitted light like the parental strain, whereas ones transfected with the repaired one did so only sparingly. Here we show that the light emission in freshwater by this strain is not in conflict with our hypothesis.

Amino Acid Sequence↗
PubMed1996

Interspecific luciferase beta subunit hybrids between Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi.

Bacterial luciferase (EC 1.14.14.3) is a heterodimer composed of alpha- and beta-chains encoded by luxA and luxB, respectively. Although some interspecific combinations of these subunits lead to active enzyme, others do not. The beta subunits of Vibrio fischeri and Photobacterium leiognathi form active enzyme with the alpha subunits of V.fischeri, P.leiognathi and Vibrio harveyi, while the beta subunit from V.harveyi only complements the alpha subunit of V.harveyi. Inactivity is caused by a lack of dimerization of the beta subunit of V.harveyi with the alpha subunits of V.fischeri and P.leiognathi. These observations served as the basis for a search to discover which segment of the beta polypeptide confers the ability to dimerize with the alpha subunits of V.fischeri and P.leiognathi. Intragenic beta subunit hybrids were made between V.harveyi, V.fischeri and P.leiognathi. Unique restriction sites were introduced into the respective luxB genes to divide them into four roughly equal segments. In all, 78 hybrids were constructed by in vitro techniques. The N-terminal segment of the peptide contains the signals that differentiate between the beta subunits of V.fischeri and P. leiognathi and the beta subunit of V. harveyi, and allow the former to dimerize with their alpha subunits. The second segment has no major effect on enzyme activity but does exhibit some context effects. Important interactions were found between the third and fourth segments of the polypeptide with respect to enzymatic activity.

Amino Acid Sequence↗
PubMed2002

Characterization of a novel Vibrio pathogenicity island (VPI-2) encoding neuraminidase (nanH) among toxigenic Vibrio cholerae isolates.

Acquisition of virulence genes encoded on mobile genetic elements has played an important role in the emergence of pathogenic isolates of Vibrio cholerae, the causative agent of the diarrhoeal disease cholera. The genes encoding cholera toxin (ctxAB), the main cause of profuse secretory diarrhoea in cholera, are encoded on a filamentous bacteriophage CTXphi. The toxin coregulated pilus (TCP), an essential intestinal colonization factor, was originally designated as part of a pathogenicity island named the Vibrio pathogenicity island (VPI), but this island has more recently been proposed to be the genome of a filamentous phage, VPIphi. In this study, it is shown that nanH, which encodes neuraminidase, maps within a novel pathogenicity island designated VPI-2. The 57.3 kb VPI-2 has all of the characteristic features of a pathogenicity island, including the presence of a bacteriophage-like integrase (int), insertion in a tRNA gene (serine) and the presence of direct repeats at the chromosomal integration sites. Additionally, the G+C content of VPI-2 (42 mol%) is considerably lower than that of the entire genome (47 mol%). VPI-2 encodes several gene clusters, such as a restriction modification system (hsdR and hsdM) and genes required for the utilization of amino sugars (nan-nag region) as well as neuraminidase. To determine the distribution of VPI-2 among V. cholerae, 78 natural isolates were examined using PCR and Southern hybridization analysis for the presence of this region. All toxigenic V. cholerae O1 serogroup isolates examined contained VPI-2, whereas non-toxigenic isolates lacked the island. Of 14 V. cholerae O139 serogroup isolates examined, only one strain, MO2, contained the entire 57.3 kb island, whereas 13 O139 isolates contained only a 20.0 kb region with most of the 5' region of VPI-2 which included nanH deleted in these strains.

Humans↗
PubMed1992

Lipopolysaccharide composition and virulence properties of clinical and environmental strains of Vibrio fluvialis and Vibrio mimicus.

Vibrio mimicus strains W-26768 (stool isolate) and N-1301 (environmental isolate) and Vibrio fluvialis strains AA-18239 (stool isolate) and M-940 (environmental isolate) were studied for virulence properties and lipopolysaccharide composition. All four strains were hydrophobic, produced cytotoxin, adhered to HeLa cells and showed mannose-sensitive agglutination of guinea pig erythrocyte. The strains were negative for enterotoxin production and were mostly susceptible to the common antibiotics. The environmental and clinical isolates of both species were antigenically unrelated to each other. Lipopolysaccharide antigen analysis showed that O-antigen polysaccharides of two strains of V. fluvialis and two strains of V. mimicus differed with respect to the sugar components. Only LPS from V. mimicus W-26768 showed the presence of an unusual sugar, 3,6-dideoxy-3-acetamido-hexose. The sugar compositions of these V. fluvialis and V. mimicus strains differed from those of previously reported Japanese isolates. These differences probably reflect differences in the serogroup of strains.

Anti-Bacterial Agents↗
PubMed1996

The thermostable direct hemolysin gene (tdh) of Vibrio hollisae is dissimilar in prevalence to and phylogenetically distant from the tdh genes of other vibrios: implications in the horizontal transfer of the tdh gene.

Vibrio hollisae strains isolated recently from patients in various locations were examined for the presence of the thermostable direct hemolysin gene (tdh) using nucleic acid hybridization and polymerase chain reaction assays. The results were consistent with the previous finding that all strains of V. hollisae carry the tdh gene. In contrast, the tdh gene has been detected in a minority of strains for other Vibrio species (V. parahaemolyticus, V. cholerae non-O1, and V. mimicus). Detailed phylogenetic analysis showed that the tdh genes of the non-V. hollisae species were very closely related to each other and that the tdh gene of V. hollisae was distantly related to the tdh genes of the non-V. hollisae species. These results and the proposed insertion sequence-mediated tdh transfer mechanism suggest that the tdh gene may have been maintained stably in V. hollisae and that the tdh genes of the non-V. hollisae species may have been involved in recent horizontal transfer.

Bacterial Proteins↗
PubMed1995

Multiplex polymerase chain reaction to detect toxigenic Vibrio cholerae and to biotype Vibrio cholerae O1.

A multiplex polymerase chain reaction (PCR) was developed to identify cholera toxin-producing Vibrio cholerae and to biotype V. cholerae O1. Enterotoxin-producing V. cholerae strains were identified with a primer pair that amplified a fragment of the ctxA2-B gene. Vibrio cholerae O1 strains were simultaneously differentiated into biotypes with three primers specified for the hylA gene in the same reaction. The hlyA amplicon in the multiplex PCR serves as an internal control when testing toxin-producing strains, as hlyA gene sequences exist in all tested V. cholerae strains. Enrichment of V. cholerae present on oysters for 6 h in alkaline peptone water before detection by a nested PCR with internal primers for ctxA2-B gene yielded a detection limit lower than 3 colony-forming units (cfu) per gram of food.

Animals↗
PubMed1995

Ribotyping and plasmid profiling of Vibrio anguillarum serovar O2 and Vibrio ordalii.

One hundred and twenty-nine strains of Vibrio anguillarum serovar O2 and 14 strains of Vibrio ordalii were ribotyped and examined for plasmid contents. A total of 35 different ribotypes were detected. The V. anguillarum serovar O2 strains were divided into 32 different ribotypes. The V. ordalii strains showed three different ribotypes, clearly distinct from those of the V. anguillarum strains. Ribotypes were separated into seven clusters, of which one comprised the V. ordalii strains. Clustering of the strains indicated a genetic difference between North European and South European V. anguillarum O2 strains. Sero-subgroups O2a and O2b shared ribotypes; however, three of the clusters did not include O2a strains. All V. ordalii strains had a plasmid of 32 kb. This plasmid was not detected in any of the V. anguillarum strains. Seventeen different plasmid profiles with 17 different sized plasmids were detected among the V. anguillarum strains. Most of the plasmids were small (< 6 kb) and found in several strains. Except for one South European strain, plasmids were detected only in the North European strains of V. anguillarum O2.

Cluster Analysis↗