Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| pathogenic and vaccine significance of toxin-coregulated pili of vibrio cholerae e1 tor. | vibrio cholerae o1 strains are classified into one of two biotypes, classical and e1 tor, the latter being primarily responsible for cholera cases worldwide since 1961. recent studies in our laboratory have focused upon the pathogenic and vaccine significance of the toxin-coregulated pili (tcp) produced by strains of e1 tor biotype. mutants in which the tcpa gene (encoding the pilin subunit protein) has been inactivated are dramatically attenuated in the infant mouse cholera model, showing marke ... | 1999 | 10486921 |
| re-emergence of vibrio cholerae o139 serogroup during 1998 in nagpur (maharashtra), india. | in nagpur, maharashtra in 1993, v. cholerae serogroup o139 emerged as a novel epidemic strain. the decline in the isolation rate of this serogroup in subsequent year was followed by its re-emergence during 1998 indicating that this serotype requires careful monitoring. | 1999 | 10489733 |
| reappearance of vibrio cholerae o139 during march-august, 1998 in ludhiana (punjab), india. | an outbreak of v. cholerae o139 was reported from ludhiana in 1993. strict bacteriological vigilance between 1994 and 1997 showed no isolates of o139, while 01 strains continued to be isolated. in 1998, 30 strains of v. cholerae o139 and 15 strains of v. cholerae 01 were isolated. both strains appear to be endemic in punjab. | 1999 | 10489734 |
| distribution of phage type of vibrio cholerae o1 biotype eltor in indian scenario (1991-98). | during the period 1991-98, distribution of biotype, serotype and phage type of v. cholerae o1 strains isolated from different parts of the country and referred to the national institute of cholera and enteric diseases, calcutta were studied. of the 8101 strains received, 5613 (69.2%) were subjected to phage typing. all these strains belonged to the biotype eltor and ogawa was the predominant serotype (96.08%). the strains were clustered into only two types--types 2 and 4 and around 10 per cent s ... | 1999 | 10491911 |
| clonal analysis of non-toxigenic vibrio cholerae o1 associated with an outbreak of cholera. | we examined the clonal relationships among eight clinical isolates of non-toxigenic (nt) v. cholerae o1 associated with a cluster of cases of cholera in warangal, andhra pradesh in south india and compared their relatedness to toxigenic o1 strains of classical and e1tor biotypes and with o139 bengal strains of v. cholerae by pulsed-field gel electrophoresis (pfge). phylogentic analysis of the noti restriction fragment length polymorphism showed that all the nt. v. cholerae o1 strains formed a ti ... | 1999 | 10491912 |
| association of vibrio cholerae o1 with the cyanobacterium, anabaena sp., elucidated by polymerase chain reaction and transmission electron microscopy. | it has been hypothesized that vibrio cholerae is an autochthonous flora of the estuarine and brackish water environment. zooplankton and phytoplankton have been considered as possible reservoirs. the present study was carried out in microcosms to confirm the role of a cyanobacterium, anabaena sp., as a reservoir of v. cholerae o1 using culture, polymerase chain reaction (pcr) and immunoelectron microscopy. survival of culturable v. cholerae in microcosms was monitored by using tellurite taurocho ... | 1999 | 10492786 |
| resurgent vibrio cholerae o139: rearrangement of cholera toxin genetic elements and amplification of rrn operon. | the unprecedented genesis of a novel non-o1 vibrio cholerae strain belonging to serogroup o139, which caused an epidemic in late 1992 in the indian subcontinent, and its subsequent displacement by el tor o1 vibrios after 18 months initiated a renewed investigation of the aspects of the organism that are related to pathogenesis. the reappearance of v. cholerae o139 with altered antibiotic sensitivity compared to o139 bengal (o139b) in late 1996 has complicated the epidemiological scenario of v. c ... | 1999 | 9864209 |
| structure-based discovery of a pore-binding ligand: towards assembly inhibitors for cholera and related ab5 toxins. | cholera toxin (ct) and escherichia coli heat-labile enterotoxin (lt) are two closely related multi-subunit ab5 proteins responsible for significant morbidity and mortality worldwide. an attractive strategy to prevent disease by these organisms is to interfere with the assembly process of these toxins, since prevention of toxin formation is better than preventing the effects of a toxin which is already formed. the b subunits form a ring with a central pore which surrounds the c-terminal residues ... | 1999 | 9887271 |
| two forms of vibrio cholerae o1 el tor hemolysin derived from identical precursor protein. | vibrio cholerae o1 grown in heart infusion broth produces two forms of el tor hemolysin (eth) monomers of 65 and 50 kda. these monomers form several different sizes of mixed oligomers ranging from 180 to 280 kda in the liposomal membranes. we found that the n-terminal amino acid sequences, nh2-trp-pro-ala-pro-ala-asn-ser-glu, of both the 65- and 50-kda toxins were identical. we assumed, therefore, that the 65- and 50-kda toxins were derivatives of the identical precursor protein and the 50-kda p ... | 1999 | 9889386 |
| microbial-host interactions at mucosal sites. host response to pathogenic bacteria at mucosal sites. | 1999 | 9893360 | |
| bacterial mucosal vaccines: vibrio cholerae as a live attenuated vaccine/vector paradigm. | 1999 | 9893363 | |
| preliminary assessment of the safety and immunogenicity of a new ctxphi-negative, hemagglutinin/protease-defective el tor strain as a cholera vaccine candidate. | vibrio cholerae 638 (el tor, ogawa), a new ctxphi-negative hemagglutinin/protease-defective strain that is a cholera vaccine candidate, was examined for safety and immunogenicity in healthy adult volunteers. in a double-blind placebo-controlled study, no significant adverse reactions were observed in volunteers ingesting strain 638. four volunteers of 42 who ingested strain 638 and 1 of 14 who received placebo experienced loose stools. the strain strongly colonized the human small bowel, as evid ... | 1999 | 9916056 |
| isolation and characterization of rugose form of vibrio cholerae o139 strain mo10. | an extracellular exopolysaccharide (slime) is produced by vibrio cholerae o139 mo10 in response to nutrient starvation. the presence of this slime layer on the cell surface and its subsequent release have been shown to be associated with biofilm formation and the change from a normal smooth colony morphology to a rugose one. an immunoelectron microscopic examination demonstrated that there is an epitope common to the exopolysaccharide antigen of v. cholerae o1 and that of o139 mo10. | 1999 | 9916115 |
| rfb mutations in vibrio cholerae do not affect surface production of toxin-coregulated pili but still inhibit intestinal colonization. | the toxin-coregulated pilus (tcp) of vibrio cholerae is essential for colonization. it was recently reported that rfb mutations in v. cholerae 569b cause the translocation arrest of the structural subunit of tcp, raising the possibility that the colonization defects of lipopolysaccharide mutants are due to effects on tcp biogenesis. however, an rfbb gene disruption in either v. cholerae o395 or 569b has no apparent effect on surface tcp production as assessed by immunoelectron microscopy and ctx ... | 1999 | 9916119 |
| quantification of bacterial lipopolysaccharides by the purpald assay: measuring formaldehyde generated from 2-keto-3-deoxyoctonate and heptose at the inner core by periodate oxidation. | we have adapted the purpald assay (m. s. quesenberry and y. c. lee, anal. biochem. 234, 50-55, 1996) to quantify lipopolysaccharide (lps) content in solution in 96-well microtiter plates at room temperature. this method employs the oxidation of unsubstituted terminal vicinal glycol groups in 2-keto-3-deoxyoctonate (kdo) and l-(or d-)glycero-d-manno-heptose of lps molecules by periodate to release formaldehyde. the formaldehyde is quantified at 550 nm (or 530-570 nm) by reacting with purpald reag ... | 1999 | 9918668 |
| purification and characterization of an aeromonas caviae metalloprotease that is related to the vibrio cholerae hemagglutinin/protease. | a zinc metalloprotease (ap34) from aeromonas caviae was purified by ammonium sulfate precipitation and subsequent gel filtration through sephadex g-100 and sephadex g-50 superfine. the molecular mass was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 34 kda. the protease showed maximum activity at ph 7.0 and was stable at 60 degrees c. ap34 was completely inactivated by edta and zincov. the n-terminal amino acid sequence of ap34 showed a high degree of homology with ... | 1999 | 9919673 |
| response of wild-type mutants of vibrio cholerae o1 possessing different combinations of virulence genes in the ligated rabbit ileal loop and in ussing chambers: evidence for the presence of additional secretogen. | five wild-type mutant strains of vibrio cholerae serogroup o1 that lacked the ctx virulence cassette, or contained a natural deletion of a virulence gene within the ctx virulence cassette, or possessed an additional virulence gene, along with a prototype toxigenic strain representing the el tor classical biotypes were examined by in-vivo and in-vitro methods to determine their enterotoxic potential. the ability of whole cells and culture supernates of the strains to cause fluid accumulation in t ... | 1999 | 9920125 |
| characterisation of cholera toxin by liquid chromatography--electrospray mass spectrometry. | cholera toxin, one of the toxins that may be generated by various strains of the bacterium vibrio cholerae, can be considered as a substance possibly used in biological warfare. the possibilities of characterising the toxin by liquid chromatography electrospray mass spectrometry (lc-es-ms) were investigated. the toxin can be detected by flow-injection (fia) es-ms of a dialysed solution and observation of the charge envelope signals of its a-unit and b-chain protein; sufficient information for id ... | 1999 | 9920483 |
| a simple, nonenzymatic method for desialylating polysialylated ganglio-n-tetraose series gangliosides to produce gm1. | dowex-50w-h+ was used to catalyze the highly selective desialylation of polysialylated ganglio-n-tetraose series gangliosides to yield primarily gm1. high performance thin-layer chromatographic analysis of recovered lipid indicated that 60-70% of the recovered ganglioside was gm1. identification of the major product as gm1 was confirmed by proton nmr spectra and lack of sialic acid release by vibrio cholerae sialidase. | 1999 | 9869662 |
| oligomerization of vibrio cholerae cytolysin yields a pentameric pore and has a dual specificity for cholesterol and sphingolipids in the target membrane. | vibrio cholerae cytolysin permeabilizes animal cell membranes. upon binding to the target lipid bilayer, the protein assembles into homo-oligomeric pores of an as yet unknown stoichiometry. pore formation has been observed with model liposomes consisting of phosphatidylcholine and cholesterol, but the latter were much less susceptible to the cytolysin than were erythrocytes or intestinal epithelial cells. we here show that liposome permeabilization is strongly promoted if cholesterol is combined ... | 1999 | 9880509 |
| the mutk gene of vibrio cholerae: a new gene involved in dna mismatch repair. | a new gene, mutk, of vibrio cholerae, encoding a 19-kda protein which is involved in repairing mismatches in dna via a presumably methyl-independent pathway, has been identified. the product of the mutk gene cloned in either high- or low-copy-number vectors can reduce the spontaneous mutation frequency of escherichia coli muts, mutl, mutu, and dam mutants. the spontaneous mutation frequency of a chromosomal mutk knockout mutant was almost identical to that of wild-type v. cholerae cells, indicat ... | 1999 | 9922251 |
| the spi-3 pathogenicity island of salmonella enterica. | pathogenicity islands are chromosomal clusters of pathogen-specific virulence genes often found at trna loci. we have determined the molecular genetic structure of spi-3, a 17-kb pathogenicity island located at the selc trna locus of salmonella enterica serovar typhimurium. the g+c content of spi-3 (47.5%) differs from that of the salmonella genome (52%), consistent with the notion that these sequences have been horizontally acquired. spi-3 harbors 10 open reading frames organized in six transcr ... | 1999 | 9922266 |
| pseudomonas aeruginosa fur overlaps with a gene encoding a novel outer membrane lipoprotein, omla. | a novel outer membrane lipoprotein in pseudomonas aeruginosa is encoded by the omla gene, which was identified immediately upstream of the fur (ferric uptake regulator) gene. the omla and fur genes were divergently transcribed and had overlapping promoter regions. the proximal fur p2 promoter and the omla promoter shared a 5-bp dna motif for their -10 promoter elements. the distal fur p1 promoter was located within the omla coding sequence, and the omla and fur t1 mrnas overlapped by 154 nucleot ... | 1999 | 9973334 |
| genetic and transcriptional analyses of the vibrio cholerae mannose-sensitive hemagglutinin type 4 pilus gene locus. | the mannose-sensitive hemagglutinin (msha) of the vibrio cholerae o1 el tor biotype is a member of the family of type 4 pili. type 4 pili are found on the surface of a variety of gram-negative bacteria and have demonstrated importance as host colonization factors, bacteriophage receptors, and mediators of dna transfer. the gene locus required for the assembly and secretion of the msha pilus has been localized to a 16.7-kb region of the v. cholerae chromosome. sixteen genes required for hemagglut ... | 1999 | 9973335 |
| genetic diversity and population structure of vibrio cholerae. | multilocus enzyme electrophoresis (mlee) of 397 vibrio cholerae isolates, including 143 serogroup reference strains and 244 strains from mexico and guatemala, identified 279 electrophoretic types (ets) distributed in two major divisions (i and ii). linkage disequilibrium was demonstrated in both divisions and in subdivision ic of division i but not in subdivision ia, which includes 76% of the ets. despite this evidence of relatively frequent recombination, clonal lineages may persist for periods ... | 1999 | 9986816 |
| cholera in vietnam: changes in genotypes and emergence of class i integrons containing aminoglycoside resistance gene cassettes in vibrio cholerae o1 strains isolated from 1979 to 1996. | the number of cholera cases and the mortality rates reported from different regions of vietnam varied considerably in the period from 1979 to 1996, with between 2,500 and 6,000 cases reported annually from 1992 to 1995. annual mortality rates ranged from 2.0 to 9.6% from 1979 to 1983 to less than 1.8% after 1983. major cholera outbreaks were reported from the high plateau region for the first time in 1994 and 1995; this is an area with limited access to health services and safe drinking-water su ... | 1999 | 9986842 |
| toxr co-operative interactions are not modulated by environmental conditions or periplasmic domain conformation. | toxr is a transmembrane regulatory protein that controls virulence gene expression in vibrio cholerae. previous experiments using lambda repressor-toxr chimeric proteins and a lambda repressor-controlled reporter system (or1 pr-laczy) established that toxr sequences can effectively dimerize the amino-terminal domain of lambda repressor in escherichia coli. however, in e. coli, toxr does not respond to environmental signals that control virulence gene expression in v. cholerae. here, we report th ... | 1999 | 9987131 |
| the structural and functional organization of h-ns-like proteins is evolutionarily conserved in gram-negative bacteria. | the structural gene of the h-ns protein, a global regulator of bacterial metabolism, has been identified in the group of enterobacteria as well as in closely related bacteria, such as erwinia chrysanthemi and haemophilus influenzae. isolated outside these groups, the bph3 protein of bordetella pertussis exhibits a low amino acid conservation with h-ns, particularly in the n-terminal domain. to obtain information on the structure, function and/or evolution of h-ns, we searched for other h-ns-rela ... | 1999 | 9987132 |
| toxin-co-regulated pilus cluster in non-o1, non-toxigenic vibrio cholerae: evidence of a third allele of pilin gene. | polymerase chain reaction has been used to detect the presence of the virulence associated gene, tcpa and part of the promoter distal region of the toxin-co-regulated pilus cluster in non-o1, non-toxigenic, vibrio cholerae. the amplified regions were characterised by restriction fragment length polymorphism and heteroduplex motility assay. we describe the nucleotide sequence of the tcpa gene fragment from non-toxigenic vibrios from clinical and environmental sources. the present study shows that ... | 1999 | 9987841 |
| differentiation of microorganisms based on pyrolysis-ion trap mass spectrometry using chemical ionization. | the ability to differentiate microorganisms using pyrolysision trap mass spectrometry was demonstrated for five gram-negative disease-causing organisms: brucella melitensis, brucella suis, vibrio cholera, yersinia pestis, and francisella tularensis. bacterial profiles were generated for gamma-irradiated bacterial samples using pyrolytic methylation and compared for electron ionization and chemical ionization using several liquid reagents with increasing proton affinities. electron ionization com ... | 1999 | 9989380 |
| vibrio cholerae o1 serotype ogawa in a neonate. | in india, cholera is endemic and affects usually the 3 to 5-year-old age group. there have been occasional reports in the neonatal period with vibrio cholerae o139 bengal. we report here a case of vibrio cholerae o1 diarrhea in a 2-day-old, breastfed male, who had been delivered in the hospital and developed severe dehydration. | 1999 | 9990478 |
| cloning and characterisation of a novel ompb operon from vibrio cholerae 569b. | the ompb operon of vibrio cholerae 569b has been cloned and fully sequenced. the operon encodes two proteins, ompr and envz, which share sequence identity with the ompr and envz proteins of a variety of other bacteria. although the order of the ompr and envz genes of v. cholerae is similar to that of the ompb operon of e. coli, s. typhimurium and x. nematophilus, the vibrio operon exhibits a number of novel features. the structural organisation and features of the v. cholerae ompb operon are des ... | 1999 | 10023081 |
| role of dnak in in vitro and in vivo expression of virulence factors of vibrio cholerae. | the dnak gene of vibrio cholerae was cloned, sequenced, and used to construct a dnak insertion mutant which was then used to examine the role of dnak in expression of the major virulence factors of this important human pathogen. the central regulator of several virulence genes of v. cholerae is toxr, a transmembrane dna binding protein. the v. cholerae dnak mutant grown in standard laboratory medium exhibited phenotypes characteristic of cells deficient in toxr activity. using northern blot anal ... | 1999 | 10024539 |
| evolutionary relationships of pathogenic clones of vibrio cholerae by sequence analysis of four housekeeping genes. | studies of the vibrio cholerae population, using molecular typing techniques, have shown the existence of several pathogenic clones, mainly sixth-pandemic, seventh-pandemic, and u.s. gulf coast clones. however, the relationship of the pathogenic clones to environmental v. cholerae isolates remains unclear. a previous study to determine the phylogeny of v. cholerae by sequencing the asd (aspartate semialdehyde dehydrogenase) gene of v. cholerae showed that the sixth-pandemic, seventh-pandemic, an ... | 1999 | 10024551 |
| zonula occludens toxin is a powerful mucosal adjuvant for intranasally delivered antigens. | zonula occludens toxin (zot) is produced by toxigenic strains of vibrio cholerae and has the ability to reversibly alter intestinal epithelial tight junctions, allowing the passage of macromolecules through the mucosal barrier. in the present study, we investigated whether zot could be exploited to deliver soluble antigens through the nasal mucosa for the induction of antigen-specific systemic and mucosal immune responses. intranasal immunization of mice with ovalbumin (ova) and recombinant zot, ... | 1999 | 10024572 |
| genetic characterization of a new type iv-a pilus gene cluster found in both classical and el tor biotypes of vibrio cholerae. | the vibrio cholerae genome contains a 5.4-kb pil gene cluster that resembles the aeromonas hydrophila tap gene cluster and other type iv-a pilus assembly operons. the region consists of five complete open reading frames designated pilabcd and yace, based on the nomenclature of related genes from pseudomonas aeruginosa and escherichia coli k-12. this cluster is present in both classical and el tor biotypes, and the pila and pild genes are 100% conserved. the pila gene encodes a putative type iv p ... | 1999 | 10024587 |
| corpses and the spread of cholera. | 1999 | 10030354 | |
| characterization and nucleotide sequence of carb-6, a new carbenicillin-hydrolyzing beta-lactamase from vibrio cholerae. | a clinical strain of vibrio cholerae non-o1 non-o139 isolated in france produced a new beta-lactamase with a pi of 5.35. the purified enzyme, with a molecular mass of 33,000 da, was characterized. its kinetic constants show it to be a carbenicillin-hydrolyzing enzyme comparable to the five previously reported carb beta-lactamases and to sar-1, another carbenicillin-hydrolyzing beta-lactamase that has a pi of 4.9 and that is produced by a v. cholerae strain from tanzania. this beta-lactamase is d ... | 1999 | 9925522 |
| identification of a vibrio cholerae rtx toxin gene cluster that is tightly linked to the cholera toxin prophage. | we identify and characterize a gene cluster in el tor vibrio cholerae that encodes a cytotoxic activity for hep-2 cells in vitro. this gene cluster contains four genes and is physically linked to the cholera toxin (ctx) element in the v. cholerae genome. we demonstrate by using insertional mutagenesis that this gene cluster is required for the cytotoxic activity. the toxin, rtxa, resembles members of the rtx (repeats in toxin) toxin family in that it contains a gd-rich repeated motif. like other ... | 1999 | 9927695 |
| a new level in the vibrio cholerae toxr virulence cascade: apha is required for transcriptional activation of the tcpph operon. | the expression of the toxr virulence regulon is dependent upon the regulatory proteins toxr/toxs, tcpp/tcph and toxt. we describe here a previously unidentified gene in vibrio cholerae, apha (activator of tcpp and tcph expression), which is required for the transcription of the tcpph operon. under conditions normally optimal for virulence gene expression, an in frame apha deletion decreased the expression of a cholera toxin promoter fusion (ctx-lacz) and prevented the production of the toxin co- ... | 1999 | 10048021 |
| antibiotic resistance conferred by a conjugative plasmid and a class i integron in vibrio cholerae o1 el tor strains isolated in albania and italy. | multidrug-resistant vibrio cholerae o1 el tor strains isolated during the 1994 outbreak of cholera in albania and italy were characterized for the molecular basis of antibiotic resistance. all strains were found to be resistant to tetracycline, streptomycin, spectinomycin, trimethoprim, sulfathiazole, and the vibriostatic compound o/129 (2,4-diamino-6,7-diisopropylteridine). resistance genes were self-transferable by a conjugative plasmid of about 60 mda, with the exception of spectinomycin resi ... | 1999 | 10049292 |
| environmental signals modulate toxt-dependent virulence factor expression in vibrio cholerae. | the regulatory protein toxt directly activates the transcription of virulence factors in vibrio cholerae, including cholera toxin (ct) and the toxin-coregulated pilus (tcp). specific environmental signals stimulate virulence factor expression by inducing the transcription of toxt. we demonstrate that transcriptional activation by the toxt protein is also modulated by environmental signals. toxt expressed from an inducible promoter activated high-level expression of ct and tcp in v. cholerae at 3 ... | 1999 | 10049382 |
| role of surface proteins in vibrio cholerae attachment to chitin. | the role of surface proteins in vibrio cholerae attachment to chitin particles in vitro was studied. treatment of v. cholerae o1 atcc 14034 and atcc 14035 with pronase e reduced the attachment of bacteria to chitin particles by 57 to 77%. a statistically significant reduction was also observed when the attachment to chitin was evaluated in the presence of homologous sarkosyl-insoluble membrane proteins (mps) (67 to 84%), n-acetylglucosamine (glcnac) (62%), the sugar that makes up chitin, and whe ... | 1999 | 10049907 |
| optimization of preparative conditions for poly-dl-lactide- polyethylene glycol microspheres with entrapped vibrio cholera antigens. | poly-dl-lactide-polyethylene glycol (pela) with different contents of polyethylene glycol(peg) were synthesized and the peg content was estimated according to the integral height of hydrogen shown in 1h-nmr. pela microspheres containing v. cholera antigen, outer membrane protein (omp) were prepared by a water-in-oil-in-water (w/o/w) based on solvent evaporation procedure. antigen microspheres with smooth surface, suitable size for oral administration (0.5-5 microm), high loading efficiency (abou ... | 1999 | 10053185 |
| phagocytosis of vibrio cholerae o139 bengal by human polymorphonuclear leukocytes. | capsulated bacteria exhibit serum (complement) resistance and resistance to phagocytosis, which result in disseminated infections. vibrio cholerae o139 strains possess a thin capsule and have been found to be partially serum resistant in a previous study. in the present study, compared to a standard capsulated klebsiella pneumoniae strain, which showed total resistance to killing by phagocytosis, v. cholerae o139 strains were shown to be only partially resistant, with most strains showing <40% s ... | 1999 | 10066668 |
| diarrheagenicity evaluation of attenuated vibrio cholerae o1 and o139 strains in the human intestine ex vivo. | the recent spread of el tor cholera in latin america highlights the need for a safe and economical vaccine. the main approach for developing live recombinant vaccines has been to disarm known pathogenic strains of cholera toxin leaving intact antigens involved in protection. these recombinant vaccine candidates do not cause severe diarrhea, but they are too reactogenic for wide scale usage. we describe here a test capable of determining the diarrheagenic potential of attenuated v. cholerae strai ... | 1999 | 10067702 |
| transmission of epidemic vibrio cholerae o1 in rural western kenya associated with drinking water from lake victoria: an environmental reservoir for cholera? | sub-saharan africa has the highest reported cholera incidence and mortality rates in the world. in 1997, a cholera epidemic occurred in western kenya. between june 1997 and march 1998, 14,275 cholera admissions to hospitals in nyanza province in western kenya were reported. there were 547 deaths (case fatality rate = 4%). of 31 vibrio cholerae o1 isolates tested, all but one were sensitive to tetracycline. we performed a case-control study among 61 cholera patients and age-, sex-, and clinic-mat ... | 1999 | 10072150 |
| the polar flagellar motor of vibrio cholerae is driven by an na+ motive force. | vibrio cholerae is a highly motile bacterium which possesses a single polar flagellum as a locomotion organelle. motility is thought to be an important factor for the virulence of v. cholerae. the genome sequencing project of this organism is in progress, and the genes that are highly homologous to the essential genes of the na+-driven polar flagellar motor of vibrio alginolyticus were found in the genome database of v. cholerae. the energy source of its flagellar motor was investigated. we exam ... | 1999 | 10074090 |
| identification and characterization of is2404 and is2606: two distinct repeated sequences for detection of mycobacterium ulcerans by pcr. | molecular analysis of mycobacterium ulcerans has revealed two new insertion sequences (iss), is2404 and is2606. is2404 was identified by complete sequencing of a previously described repetitive dna segment from m. ulcerans. this element is 1,274 bp long, contains 12-bp inverted repeats and a single open reading frame (orf) potentially encoding a protein of 327 amino acids (aa), and apparently generates 7-bp direct repeats upon transposition. amino acid similarity was found between the putative t ... | 1999 | 10074520 |
| effects of changes in membrane sodium flux on virulence gene expression in vibrio cholerae. | the expression of several virulence factors of vibrio cholerae is coordinately regulated by the toxt molecule and the membrane proteins tcpp/h and toxr/s, which are required for toxt transcription. to identify proteins that negatively affect toxt transcription, we screened transposon mutants of v. cholerae carrying a chromosomally integrated toxt::lacz reporter construct for darker blue colonies on media containing 5-bromo-4-chlor-3-indolyl beta-d galactoside (x-gal). two mutants had transposon ... | 1999 | 10077658 |
| bacterial diarrheal pathogens. | 1999 | 10079856 | |
| in vivo expression and immunoadjuvancy of a mutant of heat-labile enterotoxin of escherichia coli in vaccine and vector strains of vibrio cholerae. | vibrio cholerae secretes cholera toxin (ct) and the closely related heat-labile enterotoxin (lt) of escherichia coli, the latter when expressed in v. cholerae. both toxins are also potent immunoadjuvants. mutant lt molecules that retain immunoadjuvant properties while possessing markedly diminished enterotoxic activities when expressed by e. coli have been developed. one such mutant lt molecule has the substitution of a glycine residue for arginine-192 [lt(r192g)]. live attenuated strains of v. ... | 1999 | 10085006 |
| expanded safety and immunogenicity of a bivalent, oral, attenuated cholera vaccine, cvd 103-hgr plus cvd 111, in united states military personnel stationed in panama. | to provide optimum protection against classical and el tor biotypes of vibrio cholerae o1, a single-dose, oral cholera vaccine was developed by combining two live, attenuated vaccine strains, cvd 103-hgr (classical, inaba) and cvd 111 (el tor, ogawa). the vaccines were formulated in a double-chamber sachet; one chamber contained lyophilized bacteria, and the other contained buffer. a total of 170 partially-immune american soldiers stationed in panama received one of the following five formulatio ... | 1999 | 10085055 |
| [vibrio cholerae o139 (bengal) infection]. | 1999 | 10088330 | |
| [cholera]. | 1999 | 10088357 | |
| vibrio cholerae o1 el tor: identification of a gene cluster required for the rugose colony type, exopolysaccharide production, chlorine resistance, and biofilm formation. | the rugose colony variant of vibrio cholerae o1, biotype el tor, is shown to produce an exopolysaccharide, epsetr, that confers chlorine resistance and biofilm-forming capacity. epsetr production requires a chromosomal locus, vps, that contains sequences homologous to carbohydrate biosynthesis genes of other bacterial species. mutations within this locus yield chlorine-sensitive, smooth colony variants that are biofilm deficient. the biofilm-forming properties of epsetr may enable the survival o ... | 1999 | 10097157 |
| localization of dnak and groel in vibrio cholerae. | though the groel and dnak heat shock proteins are well characterized in prokaryotes, only scanty and controversial information exist about their cellular localization. in the present study, the localization of the heat shock proteins dnak and groel in normal and heat shocked cells of vibrio cholerae, was investigated both by immunogold labeling of ultrathin sections and biochemical methods. much of the dnak was found to be localized at the inner membrane in unstressed cells, most probably at the ... | 1999 | 10188245 |
| [vibrio cholerae temperate phage o139: characteristics and role in changing expression of chromosomal virulence genes]. | restriction analysis of temperate cholera phage 139 isolated from vibrio cholerae p16064, serogroup 0139, showed its dna to be double-stranded linear with cohesive terminals. dna-dna hybridization on nylon membranes revealed that many v. cholerae strains of serogroup 0139 isolated in different regions contained a temperate cholera phage 139 in their genomes. southern blot hybridization of chromosomal dna pst-fragments with phage probe showed that the temperate phage 139 was identical to the temp ... | 1999 | 10190102 |
| [comparative study of various methods for determining vibrio cholerae toxigenicity]. | testing of 138 vibrio cholerae strains for gene determinants responsible for the production of cholera enterotoxin by the polymerase chain reaction (pcr) and gene probing using molecular ct-probe showed good correlation of the results of different methods and correlation of these data with studies of v. cholerae strain virulence in vivo and in hemolytic activity test. the advantages of pcr in rapid assessment of the toxigenicity and epidemic significance of v. cholerae strains are demonstrated. | 1999 | 10190103 |
| analysis of an autoregulatory loop controlling toxt, cholera toxin, and toxin-coregulated pilus production in vibrio cholerae. | coordinate expression of many virulence genes in the human pathogen vibrio cholerae is controlled by the toxr, tcpp, and toxt proteins. these proteins function in a regulatory cascade in which toxr and tcpp, two inner membrane proteins, are required to activate toxt and toxt is the direct activator of virulence gene expression. toxt-activated genes include those whose products are required for the biogenesis of cholera toxin (ctx) and the toxin-coregulated pilus, the major subunit of which is tc ... | 1999 | 10198025 |
| molecular characterization of a new ribotype of vibrio cholerae o139 bengal associated with an outbreak of cholera in bangladesh. | vibrio cholerae o139 bengal initially appeared in the southern coastal region of bangladesh and spread northward, causing explosive epidemics during 1992 and 1993. the resurgence of v. cholerae o139 during 1995 after its transient displacement by a new clone of el tor vibrios demonstrated rapid changes in the epidemiology of cholera in bangladesh. a recent outbreak of cholera in two north-central districts of bangladesh caused by v. cholerae o139 led us to analyze strains collected from the outb ... | 1999 | 10203477 |
| gene capture in vibrio cholerae. | 1999 | 10203830 | |
| traditional ribotyping shows a higher discrimination than the automated riboprinter system in typing vibrio cholerae o1. | sixteen clinical vibrio cholerae o1 strains from four different countries were selected for comparison by traditional ribotyping and an automated riboprinter system for identification and discrimination purposes. automated ribotyping, which routinely uses the restriction enzyme ecori for typing all bacterial species, produced only five different ribotypes compared with 10 different ecori ribotypes obtained by the traditional method. traditional and automated ribotyping using the restriction enzy ... | 1999 | 10212447 |
| [bacteriological studies of traveller's diarrhoea (6). analysis of enteropathogenic bacteria at kansai airport quarantine station from september 4th, 1994 through december 1996]. | during the period of investigation from sept. 4, 1994 to dec, 1996, a total of 11,446,534 overseas travellers were quarantined at kansai airport quarantine station, and 22,187 voluntarily reported of episodes suffering from diarrhoea. bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained. 1) various enteropathogenic bacteria were isolated from 33.3% of the stools examined. bacterial species isolated were as follows: plesiom ... | 1999 | 10213987 |
| cloning and sequence analysis of the lipase and lipase chaperone-encoding genes from acinetobacter calcoaceticus rag-1, and redefinition of a proteobacterial lipase family and an analogous lipase chaperone family. | the genes encoding the lipase (lipa) and lipase chaperone (lipb) from acinetobacter calcoaceticus rag-1 were cloned and sequenced. the genes were isolated from a genomic dna library by complementation of a lipase-deficient transposon mutant of the same strain. transposon insertion in this mutant and three others was mapped to a single site in the chaperone gene. the deduced amino acid (aa) sequences for the lipase and its chaperone were found to encode mature proteins of 313 aa (32.5kda) and 347 ... | 1999 | 10216267 |
| site-specific integration of the conjugal vibrio cholerae sxt element into prfc. | vibrio cholerae o139, the first non-o1 serogroup of v. cholerae to give rise to epidemic cholera, is characteristically resistant to the antibiotics sulphamethoxazole, trimethoprim, chloramphenicol and streptomycin. resistances to these antibiotics are encoded by a 62 kb self-transmissible, conjugative, chromosomally integrating element designated the 'sxt element'. we found that the sxt element integrates site specifically into both v. cholerae and escherichia coli k-12 into the 5' end of prfc, ... | 1999 | 10216863 |
| characterization of the major control region of vibrio cholerae bacteriophage k139: immunity, exclusion, and integration. | the temperate bacteriophage k139 is highly associated with pathogenic o1 vibrio cholerae strains. the nucleotide sequence of the major control region of k139 was determined. the sequences of four (cox, cii, ci, and int) of the six deduced open reading frames and their gene order indicated that k139 is related to the p2 bacteriophage family. two genes of the lysogenic transcript from the mapped promoter pl encode homologs to the proteins ci and int, with deduced functions in prophage formation an ... | 1999 | 10217785 |
| purification of a mannose/glucose-specific hemagglutinin/lectin from a vibrio cholerae o1 strain. | a cell-associated mannose/glucose-specific hemagglutinin (msha) has been purified from a strain of vibrio cholerae o1 by chromatography on a chitin column followed by affinity purification on sephadex g100. the purified protein gave a single stained band of 40 kda by sds-page, exhibited high affinity towards d-mannose and d-glucose but was resistant to l-fucose and n-acetyl-d-glucosamine. the purified msha was revealed as a globular form of protein under electron microscope. in immunodiffusion t ... | 1999 | 10219594 |
| vibrio cholerae outbreak in italy. | 1999 | 10221992 | |
| analysis of 16s-23s rrna intergenic spacer regions of vibrio cholerae and vibrio mimicus. | vibrio cholerae identification based on molecular sequence data has been hampered by a lack of sequence variation from the closely related vibrio mimicus. the two species share many genes coding for proteins, such as ctxab, and show almost identical 16s dna coding for rrna (rdna) sequences. primers targeting conserved sequences flanking the 3' end of the 16s and the 5' end of the 23s rdnas were used to amplify the 16s-23s rrna intergenic spacer regions of v. cholerae and v. mimicus. two major (c ... | 1999 | 10224020 |
| transient transcriptional activation of the vibrio cholerae el tor virulence regulator toxt in response to culture conditions. | vibrio cholerae el tor require special in vitro culture conditions, consisting of an initial static growth period followed by shift to shaking (aki conditions), for expression of cholera toxin (ct) and toxin coregulated pili (tcp). toxt, a regulator whose initial transcription depends on the toxr regulator, positively modulates expression of ct and tcp. to help understand control of ct and tcp in el tor vibrios, we monitored ctxab and toxr-dependent toxt transcription by time course primer exten ... | 1999 | 10225872 |
| [the emergence of multiple antimicrobial resistance in vibrio cholerae isolated from gastroenteritis patients in ceará, brazil]. | of 7058 vibrio cholerae strains recovered from patients suspected of cholera in the state of ceará between december 1991 and september 1993, two were resistant to antimicrobials (ampicillin, erythromycin, trimethoprim-sulfamethoxazole, tetracycline) and to vibriostatic agent o/129 (2,4-diamino-6,7-diisopropylpteridine). from the bacteriological standpoint, one strain was identified as v. cholerae serogroup o:1, biotype el tor, serovar inaba, and another as v. cholerae serogroup o:22, biochemical ... | 1999 | 10228365 |
| a high proportion of vibrio cholerae strains isolated from children with diarrhoea in bangkok, thailand are multiple antibiotic resistant and belong to heterogenous non-o1, non-o139 o-serotypes. | results of a surveillance on cholera conducted with patients seen at the children hospital in bangkok, thailand from august 1993 to july 1995 are presented. annually, isolation rates for vibrio cholerae varied between 1.7 and 4.4% of patients with diarrhoea. v. cholerae o1 serotype ogawa accounted for between 31 and 47% of patients cultured positive for v. cholerae, whereas the o139 serotype dominated in early 1994 after which it disappeared. non-o1, non-0139 strains were isolated at similar rat ... | 1999 | 10355785 |
| [the isolation of monoclonal antibodies to the hemolysin of noncholerigenic vibrios]. | the results of the work on obtaining monoclonal antibodies (mcab) to hemolysin of noncholerigenic vibrios and the study of hemolysin preparations and vibrio cholerae strains are presented. as established with the use of mcab, hemolysin preparations proved to be complex compounds containing, in addition to hemolytic protein, some lipopolysaccharide determinants, which had not been detected with the use of traditional biochemical tests. the study revealed that v. cholerae non-01 and v. cholerae el ... | 1999 | 10356728 |
| [the isolation and comparative characteristics of sera to the enterotoxin of vibrio cholerae of the serogroups o139 and o1]. | 1999 | 10356747 | |
| vibrio cholerae o2 sepsis in a patient with aids. | vibrio cholerae strains other than o1 and 0139 (non-o1 vibrio cholerae) are associated with sporadic diarrheal disorders and limited outbreaks of diarrhea and have often been reported in association with extraintestinal infections. the following is a presentation of a fatal case of non-o1 vibrio cholerae septicemia with disseminated intravascular coagulation and cutaneous bullous lesions that occurred in a patient infected with the acquired immunodeficiency syndrome. in order to prevent vibrio c ... | 1999 | 10357055 |
| significance of cryptosporidium in acute diarrhoea in north-eastern india. | in a hospital-based study, stool samples from 2095 patients of all ages were examined for different fungal, protozoal and bacterial enteropathogens over a period of 2 years (july 1994-june 1996). cryptosporidium was detected in 151 specimens (7.2%) and was the third commonest pathogen found. the highest prevalence of this organism was in the group aged 16-45 years and during the rainy months (july-oct.). diarrhoea caused by the protozoon was of mild to moderate severity and features of dysentery ... | 1999 | 10359300 |
| virus on virus infects bacterium. | 1999 | 10360569 | |
| a bacteriophage encoding a pathogenicity island, a type-iv pilus and a phage receptor in cholera bacteria. | the virulence properties of many pathogenic bacteria are due to proteins encoded by large gene clusters called pathogenicity islands, which are found in a variety of human pathogens including escherichia coli, salmonella, shigella, yersinia, helicobacter pylori, vibrio cholerae, and animal and plant pathogens such as dichelobacter nodosus and pseudomonas syringae. although the presence of pathogenicity islands is a prerequisite for many bacterial diseases, little is known about their origins or ... | 1999 | 10360577 |
| rapid structural characterisation of a murine monoclonal iga alpha chain: heterogeneity in the oligosaccharide structures at a specific site in samples produced in different bioreactor systems. | a murine hybridoma cell line which secretes a monoclonal iga antibody, directed against the lps antigen of vibrio cholerae, was grown in either a continuous stirred tank reactor, a fluidised bed reactor or a hollow fibre reactor. different methods were used for the structural characterisation of the iga alpha chains. a classical approach consisted of edman sequencing and mass determination of peptides separated by reversed phase hplc. alternatively, peptides and glycopeptides from a tryptic dige ... | 1999 | 10361726 |
| [cholera++ epidemic in kenya]. | a cholera epidemic in 1997 followed on the heels of the 1992 epidemic that claimed thousands of victims in kenya. this time, it emerged in the migori district near the tanzanian border, when a woman who had married in tanzania brought her five-month-old baby to visit her parents. the infant, who contracted serious diarrhea and vomiting, died before the mother could reach a dispensary. during the funeral, a perfect opportunity for the disease to spread, those attending observed the traditional ri ... | 1999 | 10362941 |
| time for a fresh look at the bacterial chromosome. | 1999 | 10366858 | |
| mortality in severely malnourished children with diarrhoea and use of a standardised management protocol. | severely malnourished children have high mortality rates. death commonly occurs during the first 48 h after hospital admission, and has been attributed to faulty case-management. we developed a standardised protocol for acute-phase treatment of children with severe malnutrition and diarrhoea, with the aim of reducing mortality. | 1999 | 10371570 |
| mucosal and systemic immune responses in humans after primary and booster immunizations with orally administered invasive and noninvasive live attenuated bacteria. | the mucosal and systemic immune responses after primary and booster immunizations with two attenuated live oral vaccine strains derived from a noninvasive (vibrio cholerae) and an invasive (salmonella typhi) enteric pathogen were comparatively evaluated. vaccination with s. typhi ty21a elicited antibody-secreting cell (asc) responses specific for s. typhi o9, 12 lipopolysaccharide (lps), as well as significant increases in levels of immunoglobulin g (igg) and iga antibodies to the same antigen i ... | 1999 | 10377160 |
| characterization of a dam mutant of serratia marcescens and nucleotide sequence of the dam region. | the dna of serratia marcescens has n6-adenine methylation in gatc sequences. among 2-aminopurine-sensitive mutants isolated from s. marcescens sr41, one was identified which lacked gatc methylation. the mutant showed up to 30-fold increased spontaneous mutability and enhanced mutability after treatment with 2-aminopurine, ethyl methanesulfonate, or uv light. the gene (dam) coding for the adenine methyltransferase (dam enzyme) of s. marcescens was identified on a gene bank plasmid which alleviate ... | 1999 | 10383952 |
| development of primers to o-antigen biosynthesis genes for specific detection of escherichia coli o157 by pcr. | the chemical composition of each o-antigen subunit in gram-negative bacteria is a reflection of the unique dna sequences within each rfb operon. by characterizing dna sequences contained with each rfb operon, a diagnostic serotype-specific probe to escherichia coli o serotypes that are commonly associated with bacterial infections can be generated. recently, from an e. coli o157:h7 cosmid library, o-antigen-positive cosmids were identified with o157-specific antisera. by using the cosmid dnas as ... | 1999 | 10388689 |
| intranasal administration of a schistosoma mansoni glutathione s-transferase-cholera toxoid conjugate vaccine evokes antiparasitic and antipathological immunity in mice. | mucosal administration of ags linked to cholera toxin b subunit (ctb) can induce both strong mucosal secretory iga immune responses and peripheral t cell hyporeactivity. in this study, intranasal (i.n. ) administration of ctb-conjugated schistosoma mansoni 28-kda gst (ctb-sm28gst) was found to protect infected animals from schistosomiasis, especially from immunopathological complications associated with chronic inflammation. worm burden and liver egg counts were reduced in infected animals treat ... | 1999 | 10395703 |
| risk screening for exposure to groundwater pollution in a wastewater irrigation district of the mexico city region. | untreated wastewater from the mexico city basin has been used for decades to irrigate cropland in the mezquital valley, state of hidalgo, mexico. excess irrigation water recharges the near-surface aquifer that is used as a domestic water supply source. we assessed the groundwater quality of three key groundwater sources of domestic water by analyzing for 24 trace metals, 67 target base/neutral/acid (bna) organic compounds, nontarget bna organics, 23 chlorinated pesticides, 20 polychlorinated bip ... | 1999 | 10398590 |
| identification and initial characterization of elastase activity associated with vibrio cholerae. | strains of vibrio cholerae o1 (ogawa, inaba) and non-o1 serogroups have been found to produce an elastolytic protease that can be detected on 0.3% elastin agar plates or in broth cultures. the elastase enzyme appears to be maximally expressed in late log phase (14-18 h postinoculation) and has optimum activity at a ph range between 7 and 8. comparative studies indicate that more than 60% of v. cholerae strains analyzed quantitatively produce more elastase in broth (two- to fourfold higher) than ... | 1999 | 10398830 |
| a vibrio cholerae lysr homolog, aphb, cooperates with apha at the tcpph promoter to activate expression of the toxr virulence cascade. | we describe here a new member of the lysr family of transcriptional regulators, aphb, which is required for activation of the vibrio cholerae toxr virulence cascade. aphb activates the transcription of the tcpph operon in response to environmental stimuli, and this process requires cooperation with a second protein, apha. the expression of neither apha or aphb is strongly regulated by environmental stimuli, raising the possibility that the activities of the proteins themselves may be influenced ... | 1999 | 10400582 |
| the chemotactic response of vibrio anguillarum to fish intestinal mucus is mediated by a combination of multiple mucus components. | chemotactic motility has previously been shown to be essential for the virulence of vibrio anguillarum in waterborne infections of fish. to investigate the mechanisms by which chemotaxis may function during infection, mucus was isolated from the intestinal and skin epithelial surfaces of rainbow trout. chemotaxis assays revealed that v. anguillarum swims towards both types of mucus, with a higher chemotactic response being observed for intestinal mucus. work was performed to examine the basis, i ... | 1999 | 10400589 |
| first do no harm: making oral rehydration solution safer in a cholera epidemic. | oral rehydration solution (ors) is lifesaving therapy for cholera and pediatric diarrhea. during a cholera epidemic in guinea-bissau, we evaluated the microbiologic quality of ors prepared at a hospital and tested a simple intervention using special vessels for disinfecting tap water with bleach and for preparing, storing, and dispensing ors. few coliform bacteria and escherichia coli were recovered from tap water; however, pre-intervention ors contained numerous bacteria including e. coli and t ... | 1999 | 10403342 |
| v cholerae non-o1: implications for man? | 1999 | 10408479 | |
| mutk may be a 32 kda protein and be widespread among proteobacteria. | 1999 | 10411738 | |
| faecal excretion of vibrio cholerae during convalescence of cholera patients in calabar, nigeria. | the pattern of faecal excretion of vibrio cholerae was studied over a duration of eight months among 13 cholera convalescents by two-weekly surveillance cultures. stools and rectal swabs were cultured on thiosulphate citrate bile salts sucrose (tcbs) agar for the recovery of vibrio pathogens. clinical phase and convalescent phase v. cholerae strains were compared for antibiogram profiles. the population of vibrios recovered from faecal inocula was usually scanty (<10(3) vibrios/g). all clinical ... | 1999 | 10414380 |
| vibrio cholerae intestinal population dynamics in the suckling mouse model of infection. | the suckling mouse has been used as a model to identify vibrio cholerae intestinal colonization factors for over two decades, yet little is known about the location of recoverable organisms along the gastrointestinal (gi) tract following intragastric inoculation. in the present study, we determined the population dynamics of wild-type and avirulent mutant derivatives of both classical and el tor biotype strains throughout the entire suckling mouse gi tract at various times after intragastric ino ... | 1999 | 10417131 |
| microbiological quality of retail imported unprepared whole lettuces: a phls food working group study. public health laboratory service. | a study of imported unprepared whole lettuces sampled from supermarkets, greengrocers, shops, and market stalls found that all were of acceptable microbiological quality. twenty-seven out of 151 (18%) imported lettuce samples had enterobacteriaceae levels of 10(4) cfu/g or more. however, these bacteria that constitute part of the natural microflora of unprepared vegetables may also be derived from the soil and/or by poor handling. the pathogens, salmonella spp., shigella spp., campylobacter spp. ... | 1999 | 10419203 |
| use of selective media to recover salmonella and vibrio cholerae after growth in reconditioned pork-processing wastewater. | selective plating media are used for the enumeration and isolation of bacterial pathogens from food and water samples. this study compared the quantitative recovery of salmonella spp. and vibrio cholerae grown in nutrient-limited, filter-sterilized, reconditioned wastewater over the temperature range of 4 to 45 degrees c using nonselective and pathogen-specific selective media. viable salmonella were enumerated on tryptic soy agar (tsa) and xlt-4, and viable v. cholerae were enumerated on tsa an ... | 1999 | 10419262 |
| construction of a recombinant live oral vaccine from a non-toxigenic strain of vibrio cholerae o1 serotype inaba biotype e1 tor and assessment of its reactogenicity and immunogenicity in the rabbit model. | the disease cholera is an important cause of mortality in many developing countries. though it can be controlled through improved sanitation, this goal is not easily attainable in many countries. development of an efficacious vaccine offers the best immediate solution. a new oral candidate vaccine has been constructed from a non-toxigenic strain of vibrio cholerae e1 tor, inaba, which is not only devoid of the cholera toxin (ct) virulence cassette but also is completely non-reactogenic in rabbit ... | 1999 | 10424424 |
| cloning and sequencing of the genes downstream of the wbf gene cluster of vibrio cholerae serogroup o139 and analysis of the junction genes in other serogroups. | the dna sequence of the o-antigen biosynthesis cluster (wbf) of a recently emergent pathogen, vibrio cholerae serogroup o139, has been determined. here we report the sequence of the genes downstream of the o139 wbfx gene and analysis of the genes flanking the wbf gene cluster in other serogroups. the gene downstream of wbfx, designated rjg (right junction gene), is predicted to be not required for o-antigen biosynthesis but appears to be a hot spot for dna rearrangements. several variants of the ... | 1999 | 10496875 |