Publications

molecular analyses of a putative ctxphi precursor and evidence for independent acquisition of distinct ctx(phi)s by toxigenic vibrio cholerae.	the genes encoding cholera toxin (ctxa and ctxb) are encoded in the genome of ctxphi, a filamentous phage that infects vibrio cholerae. to study the evolutionary history of ctxphi, we examined genome diversity in ctx(phi)s derived from a variety of epidemic and nonepidemic vibrio sp. natural isolates. among these were three v. cholerae strains that contained ctx prophage sequences but not the ctxa and ctxb genes. these prophages each gave rise to a plasmid form whose genomic organization was ver ...	2000	10986258
cholera vaccines.	cholera causes significant morbidity and mortality worldwide. for travelers, the risk of developing cholera per month of stay in a developing country is approximately 0.001%-0.01%, and cholera may present as traveler's diarrhea. in the united states, only a poorly tolerated, marginally effective, parenterally administered, phenol-inactivated vaccine is available. outside the united states, 2 additional vaccines are commercially available: an oral killed whole cell-cholera toxin recombinant b sub ...	2000	10987721
genomics happens.	cholera has been the scourge of humankind for centuries. although most of the time vibrio cholerae, the microbe that causes this disease, is a free-living organism inhabiting aquatic environments, it can invade human hosts causing severe diarrhea and often death. as dirita explains in his perspective, sequencing of the entire v. cholerae genome is revealing new facets of the pathogenesis of this dangerous microbe.	2000	10991736
purification and characterization of a cytotonic protein expressed in vitro by the live cholera vaccine candidate cvd 103-hgr.	cholera vaccines developed by the deletion of ctx genes from vibrio cholerae induce a residual reactogenicity in up to 10% of vaccinees. a novel cytotonic agent named secreted cho cell elongating protein (s-cep) was purified from culture supernatants of cvd 103-hgr (levine et al., lancet ii:467-470, 1988). five fractionation steps yielded electrophoretically pure s-cep with an m(r) of 79,000. a partially purified preparation caused fluid accumulation in the sealed infant mouse model. the amino t ...	2000	10992523
enterotoxin-specific immunoglobulin e responses in humans after infection or vaccination with diarrhea-causing enteropathogens.	cholera toxin (ct)-specific antibody responses of the immunoglobulin e (ige) isotype in the sera of adult patients suffering from infection with either vibrio cholerae o1, v. cholerae o139, or enterotoxigenic escherichia coli (etec) were analyzed and compared with those in the sera of volunteers immunized with a bivalent b subunit o1/o139 whole-cell cholera vaccine. a significant ige response to ct was observed in 90% of the patients with v. cholerae o1 infection (18 of 20; p = <0.001) and 95% o ...	2000	10992527
cholera toxin and related enterotoxins: a cell biological and immunological perspective.	cholera toxin (ctx) from vibrio cholerae and the closely related escherichia coli heat-labile enterotoxin (etx) are the primary virulence factors responsible for causing cholera and traveller's diarrhea, respectively. studies on the mode of action of these toxins on gut epithelial cells have revealed important insights into the mechanisms of toxin uptake and trafficking in eukaryotic cells. however, of perhaps even greater fascination have been the discoveries that ctx and etx exhibit remarkable ...	2000	10994530
translocases: a bacterial tunnel for drugs and proteins.	unrelated translocases extrude proteins or antimicrobial agents across both membranes of the cell envelope in gram-negative bacteria. the tolc protein links the translocases to the external environment. the recently determined crystal structure of tolc shows how this universal tunnel operates.	2000	10996810
a putative heat-labile enterotoxin expressed by strains of aeromonas media.	fifteen isolates of aeromonas media (seven from diarrhoeal stools, four from water and four from superficial skin ulcers of catfish) were examined for enterotoxin production. ten of these isolates (six diarrhoeal, one from water and three from fish) caused accumulation of fluid in the initial rabbit ileal loop (ril) tests. isolates from diarrhoeal stools and fish caused relatively more fluid accumulation than those from water. those strains that caused little or no fluid accumulation in the init ...	2000	10933251
vaccines for the future: problems and potential solutions from the countries that need them.		2000	10934500
effect of iron on the survival of vibrio cholerae in water.	effect of iron in the form of ferric oxide (fe2o3) on the survival of v. cholerae o1 was studied. v. cholerae o1 survived for 8 days in plain water whereas in presence of fe2o3 it survived up to 15 days. presence of organic material in the water further promoted the bacterial survival by at least 4 days. there was no difference between the behaviour of el tor and classical biotype. these results indicate that the presence of iron in water could promote the survival of v. cholerae o1 in water and ...	2000	10935316
entry into and release of solvents by escherichia coli in an organic-aqueous two-liquid-phase system and substrate specificity of the acrab-tolc solvent-extruding pump.	growth of escherichia coli is inhibited upon exposure to a large volume of a harmful solvent, and there is an inverse correlation between the degree of inhibition and the log p(ow) of the solvent, where p(ow) is the partition coefficient measured for the partition equilibrium established between the n-octanol and water phases. the acrab-tolc efflux pump system is involved in maintaining intrinsic solvent resistance. we inspected the solvent resistance of delta acrab and/or delta tolc mutants in ...	2000	10940021
development of hyperfimbriated strains of vibrio cholerae o1.	the vibrio cholerae o1 and o139 fimbrillin genes (fima or msha) were amplified by polymerase chain reaction and cloned into an escherichia coli pcr vector. these clones were sequenced. the fima sequences were found to be identical between v cholerae o1 and o139. one of the plasmids was digested with ecor i and inserted into the ecor i site of pgex-3x. the plasmid pvpp thus obtained was transferred into strains of wild-type v cholerae o1 bgd17 (classical in biotype) and its fimbriated strain by e ...	2000	10941926
vibrio cholerae ace stimulates ca(2+)-dependent cl(-)/hco(3)(-) secretion in t84 cells in vitro.	ace, accessory cholera enterotoxin, the third enterotoxin in vibrio cholerae, has been reported to increase short-circuit current (i(sc)) in rabbit ileum and to cause fluid secretion in ligated rabbit ileal loops. we studied the ace-induced change in i(sc) and potential difference (pd) in t84 monolayers mounted in modified ussing chambers, an in vitro model of a cl(-) secretory cell. ace added to the apical surface alone stimulated a rapid increase in i(sc) and pd that was concentration dependen ...	2000	10942706
evaluation of oral hypo-osmolar glucose-based and rice-based oral rehydration solutions in the treatment of cholera in children.	in a randomized controlled clinical trial, the efficacy of a low-sodium low-glucose oral rehydration solution (ors) and a low-sodium rice-based ors was compared with standard who glucose ors in the treatment of severe cholera in children aged 2-10y. in total, 120 children were evaluated for the study, of whom 58 patients were positive for vibrio cholerae and were included in the study. of these 58 cases, 19 received rice-based hypo-osmolar ors, 20 received who-ors and 19 received glucose-based h ...	2000	10943958
altered expression of the toxr-regulated porins ompu and ompt diminishes vibrio cholerae bile resistance, virulence factor expression, and intestinal colonization.	the transmembrane transcriptional activators toxr and tcpp modulate expression of vibrio cholerae virulence factors by exerting control over toxt, which encodes the cytoplasmic transcriptional activator of the ctx, tcp, and acf virulence genes. however, toxr, independently of tcpp and toxt, activates and represses transcription of the genes encoding two outer-membrane porins, ompu and ompt. to determine the role of toxr-dependent porin regulation in v. cholerae pathogenesis, the toxr-activated o ...	2000	10944196
prevalence and virulence properties of vibrio cholerae non-o1, aeromonas spp. and plesiomonas shigelloides isolated from cambé stream (state of paraná, brazil).	the incidence of vibrio cholerae, aeromonas spp. and plesiomonas shigelloides was determined in water samples from cambé stream. the samples were collected from seven different sites. the serogroups, virulence markers and drug resistance profiles were also evaluated. twelve aer. hydrophila, 12aer. caviae, eight aer. sobria, seven ple. shigelloides and two v. cholerae non-o1 were isolated. they belonged to different serogroups and all produced haemolysis in different assays. five of the aeromonas ...	2000	10945781
nontoxigenic vibrio cholerae o1 bacteremia: case report and review.		2000	10947231
phagocytic cell killing mediated by secreted cytotoxic factors of vibrio cholerae.	vibrio cholerae strain vb1 secretes a number of enzymes into the outside medium that utilize atp as a substrate. such enzymes are found in the outside medium during the mid-log phase of growth, when the optical density at 650 nm is about 0.4, and they demonstrate nucleoside diphosphate kinase (ndk), 5' nucleotidase, and adenylate kinase (ak) activities. we report that the filtered growth medium of v. cholerae, as well as the flowthrough fraction of a green sepharose column during fractionation o ...	2000	10948107
vibrio cholerae o139 conjugate vaccines: synthesis and immunogenicity of v. cholerae o139 capsular polysaccharide conjugates with recombinant diphtheria toxin mutant in mice.	epidemiologic and experimental data provide evidence that a critical level of serum immunoglobulin g (igg) antibodies to the surface polysaccharide of vibrio cholerae o1 (lipopolysaccharide) and of vibrio cholerae o139 (capsular polysaccharide [cps]) is associated with immunity to the homologous pathogen. the immunogenicity of polysaccharides, especially in infants, may be enhanced by their covalent attachment to proteins (conjugates). two synthetic schemes, involving 1-ethyl-3-(3-dimethylaminop ...	2000	10948122
treasure trove for cholera research.		2000	10952295
dna sequence of both chromosomes of the cholera pathogen vibrio cholerae.	here we determine the complete genomic sequence of the gram negative, gamma-proteobacterium vibrio cholerae el tor n16961 to be 4,033,460 base pairs (bp). the genome consists of two circular chromosomes of 2,961,146 bp and 1,072,314 bp that together encode 3,885 open reading frames. the vast majority of recognizable genes for essential cell functions (such as dna replication, transcription, translation and cell-wall biosynthesis) and pathogenicity (for example, toxins, surface antigens and adhes ...	2000	10952301
characterization of vibrio cholerae o1 antigen as the bacteriophage k139 receptor and identification of is1004 insertions aborting o1 antigen biosynthesis.	bacteriophage k139 was recently characterized as a temperate phage of o1 vibrio cholerae. in this study we have determined the phage adsorption site on the bacterial cell surface. phage-binding studies with purified lipopolysaccharide (lps) of different o1 serotypes and biotypes revealed that the o1 antigen serves as the phage receptor. in addition, phage-resistant o1 el tor strains were screened by using a virulent isolate of phage k139. analysis of the lps of such spontaneous phage-resistant m ...	2000	10960093
predicted highly expressed genes of diverse prokaryotic genomes.	our approach in predicting gene expression levels relates to codon usage differences among gene classes. in prokaryotic genomes, genes that deviate strongly in codon usage from the average gene but are sufficiently similar in codon usage to ribosomal protein genes, to translation and transcription processing factors, and to chaperone-degradation proteins are predicted highly expressed (phx). by these criteria, phx genes in most prokaryotic genomes include those encoding ribosomal proteins, trans ...	2000	10960111
nhaa, an na(+)/h(+) antiporter involved in environmental survival of vibrio cholerae.	vibrio cholerae, the agent of cholera, is a normal inhabitant of aquatic environments, in which it survives under a wide range of conditions of ph and salinity. in this work, we identified the nhaa gene in a wild-type epidemic strain of v. cholerae o1. nhaa encodes a protein of 382 amino acids that is very similar to the proteins nhaa of vibrio parahaemolyticus, vibrio alginolyticus ( approximately 87% identity), and escherichia coli (56% identity). v. cholerae nhaa complements an e. coli nhaa m ...	2000	10781565
bacteremic cellulitis caused by non-01, non-0139 vibrio cholerae: report of a case in a patient with hemochromatosis.	we report a case of bacteremia associated with hemorrhagic bullous skin lesions on the leg caused by non-01, non-0139 vibrio cholerae in a 66-year-old man with hemochromatosis developed in an inland region. the organism was isolated from blood and bullae fluid. the patient was treated successfully with cefotaxime and doxycycline. this report emphasizes the potential of this organism to produce bacteremic cellulitis in people with underlying illness in the absence of usual epidemiological risk fa ...	2000	10794945
zonulin, a newly discovered modulator of intestinal permeability, and its expression in coeliac disease.	we identified zonulin, a novel human protein analogue to the vibrio cholerae derived zonula occludens toxin, which induces tight junction disassembly and a subsequent increase in intestinal permeability in non-human primate intestinal epithelia. zonulin expression was raised in intestinal tissues during the acute phase of coeliac disease, a clinical condition in which tight junctions are opened and permeability is increased.	2000	10801176
[a dried nutrient medium for the isolation of vibrio cholerae].	a dried differential nutrient medium for the isolation of v. cholerae has been developed. the medium is sufficiently sensitive, has pronounced differentiating properties and greatly inhibits the appearance of microbial associations. during the cultivation of v. cholerae with the use of this medium the cultural, morphological and agglutination properties of the initial strains are retained.	2000	10808569
vibrio cholerae o139 in calcutta, 1992-1998: incidence, antibiograms, and genotypes.	we report results of surveillance for cholera caused by vibrio cholerae o139 from september 1992, when it was first identified, to december 1998. v. cholerae o139 dominated as the causative agent of cholera in calcutta during 1992-93 and 1996- 97, while the o1 strains dominated during the rest of the period. dramatic shifts in patterns of resistance to cotrimoxazole, neomycin, and streptomycin were observed. molecular epidemiologic studies showed clonal diversity among the o139 strains and conti ...	2000	10756147
vibrio cholerae o2 as a cause of a skin lesion in a tourist returning from tunisia.	isolates of vibrio cholerae other than o1 and o139 (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 majority of cases of non o1 vibrio cholerae infection involve immunocompromised patients with hematologic malignancies or cirrhosis. in italy, very few cases of gastrointestinal and extraintestinal infections due to non o1 vibrio cholerae have been described ...	2000	10759577
convergence of the secretory pathways for cholera toxin and the filamentous phage, ctxphi.	virulence of vibrio cholerae depends on secretion of cholera toxin (ct), which is encoded within the genome of a filamentous phage, ctxphi. release of ct is mediated by the extracellular protein secretion (eps) type ii secretion system. here, the outer membrane component of this system, epsd, was shown to be required for secretion of the phage as well. thus, epsd plays a role both in pathogenicity and in horizontal transfer of a key virulence gene. genomic analysis suggests that additional filam ...	2000	10764646
survival of vibrio cholerae o1 in ceviche and its reduction by heat pretreatment of raw ingredients.	the survival of vibrio cholerae o1 serotypes inaba and ogawa was determined in ceviche prepared from inoculated ground fish. ground mackerel purchased from a seafood distribution center was inoculated with v. cholerae and stored at 8 or 20 degrees c. counts of v. cholerae decreased in 2.6 to 2.7 log10 cfu/g during 96 h of storage at 8 degrees c or 2.5 to 2.6 log10 cfu/g during 24 h at 20 degrees c. survival studies indicated that serotype inaba decreased its number following a linear or retarded ...	2000	10772208
vibrio cholerae h-ns silences virulence gene expression at multiple steps in the toxr regulatory cascade.	h-ns is an abundant nucleoid-associated protein involved in the maintenance of chromosomal architecture in bacteria. h-ns also has a role in silencing the expression of a variety of environmentally regulated genes during growth under nonpermissive conditions. in this study we demonstrate a role for h-ns in the negative modulation of expression of several genes within the toxr virulence regulon of vibrio cholerae. deletion of hns resulted in high, nearly constitutive levels of expression of the g ...	2000	10894740
sunlight-induced propagation of the lysogenic phage encoding cholera toxin.	in toxigenic vibrio cholerae, the cholera enterotoxin (ct) is encoded by ctxphi, a lysogenic bacteriophage. the propagation of this filamentous phage can result in the origination of new toxigenic strains. to understand the nature of possible environmental factors associated with the propagation of ctxphi, we examined the effects of temperature, ph, salinity, and exposure to direct sunlight on the induction of the ctx prophage and studied the transmission of the phage to potential recipient stra ...	2000	10899892
[the determination of the optimal conditions for the production of a number of pathogenicity factors in vibrio cholerae].	conditions for the cultivation of v. cholerae of different sero- and biovars on tryptone medium, ensuring the maximum production of cholera toxin (ct), dermonecrotic factor (dnf), hemorrhagic factor (hf) and new cholera toxin (nct) have been determined. the lack of coincidence in the optimum conditions ensuring the maximum production of ct, dnf and hf has been established, which may be indicative of different nature of these toxic substances. nct, produced by vct- strains, is similar to cn in bi ...	2000	10876885
[noncapsular mutants of vibrio cholerae serogroup o139: their isolation, identification and use for the preparation of an o139 diagnostic antiserum].	on the basis of v. cholerae strain p16064, serogroup o139, spontaneous and transposon mutants with the stable lose of the capacity for producing the polysaccharide capsule, but retaining antigen o139, have been obtained. as revealed in this study, capsular and noncapsular strains differ in their sensitivity to cholera phages 20 and inaba, as well as in agglutination with o139-antiserum. these data make it possible to use of bacteriophages for the differentiation of capsular and noncapsular strai ...	2000	10876889
protection from cholera by adding lime juice to food - results from community and laboratory studies in guinea-bissau, west africa.	epidemiological studies have shown that food plays an important role in the transmission of vibrio cholerae, and different foods have been incriminated in many epidemic outbreaks of cholera. storing contaminated meals at ambient temperatures allows growth of v. cholerae. some ingredients such as lime juice may inhibit the survival of v. cholerae in foods. during an epidemic caused by v. cholerae o1 in guinea-bissau in 1996, a case control study was conducted in the capital bissau, the main affec ...	2000	10929141
passive protection of serum from volunteers inoculated with attenuated strain 638 of vibrio cholerae o1 in animal models.	as part of the studies to obtain an oral vaccine against cholera disease, the protective effect of serum from volunteers inoculated in a controlled trial with a candidate live attenuated vaccine of vibrio cholerae o1, el tor ogawa (638; ctxφ mutant, hap::cela), was tested. it was confirmed that the serum, as well as the purified igg and iga from the volunteers had a protective effect in both of the animal models used, although the purified antibodies needed the presence of complement to be p ...	2000	10930693
purification and characterization of n-acetylglucosamine-6-phosphate deacetylase from a psychrotrophic marine bacterium, alteromonas species.	a psychrotrophic bacterium, strain mct-9, which produced an n-acetylglucosamine-6-phosphate deacetylase, was isolated from a deep-seawater sample in the mariana trough. the mct-9 strain was identified as alteromonas sp. the native enzyme had a molecular mass of 164,000 da, and was predicted to be composed of four identical subunits with molecular masses of 41,000 da. the purified enzyme hydrolyzed n-acetylglucosamine (glcnac), glcnac-6-phosphate, and glcnac-6-sulfate. considering the low k(m) an ...	2000	10804240
the marine pathogen vibrio vulnificus encodes a putative homologue of the vibrio harveyi regulatory gene, luxr: a genetic and phylogenetic comparison.	vibrio vulnificus is an opportunistic pathogen that exhibits numerous virulence factors, including the secretion of a zinc metalloprotease and the production of a capsule. we have cloned and sequenced a gene from v. vulnificus that is a homologue of the positive transcriptional regulator, luxr, of the lux operon in vibrio harveyi. this gene encodes a putative, single complete open reading frame designated smcr, which shares greater than 75% nucleotide identity with luxr of v. harveyi. the deduce ...	2000	10806366
differential activation of the tcpph promoter by aphb determines biotype specificity of virulence gene expression in vibrio cholerae.	vibrio cholerae strains of the classical biotype express the genes encoding cholera toxin (ct) and toxin-coregulated pilus (tcp) under a variety of environmental conditions in vitro, whereas el tor biotype strains express these genes only under specialized culture conditions. we show here that a single base-pair difference at positions -65 and -66 of the classical and el tor tcpph promoters, respectively, is responsible for the differential regulation of virulence gene expression in these two di ...	2000	10809704
ecological study of vibrio cholerae in vellore.	vellore is endemic for cholera due to vibrio cholerae o1 and o139. in a previous study the prevalence of vibrio cholerae in drinking water, lakes and sewage outfalls in a single 2-months period in vellore, india was determined. in addition water samples from three sites were also tested for the presence of v. cholerae o1 and o139 by fluorescent antibody staining. this follow on study has examined how the environmental distribution of v. cholerae at the same sites alters over a 12-month period an ...	2000	10813143
identification of a novel gene, fimv, involved in twitching motility in pseudomonas aeruginosa.	transposon mutagenesis was used to identify a new locus required for twitching motility in pseudomonas aeruginosa. four tn5-b21 mutants which lacked twitching motility and a fifth which exhibited impaired motility were found to map to the same kpn:i restriction fragment at approximately 40 min on the p. aeruginosa genome. cloning and sequencing studies showed that all five transposon insertions occurred within the same 2.8 kb orf, which was termed fimv. the product of this gene has a putative pe ...	2000	10846211
detection and analysis of gene expression during infection by in vivo expression technology.	many limitations associated with the use of in vitro models for study of bacterial pathogenesis can be overcome by the use of technologies that detect pathogen gene expression during the course of infection within an intact animal. in vivo expression technology (ivet) accomplishes this with versatility: it has been developed with a variety of reporter systems which allow for either in vivo selection or ex vivo screening. selectable gene fusion systems generally allow for the complementation of a ...	2000	10874732
requirements for conversion of the na(+)-driven flagellar motor of vibrio cholerae to the h(+)-driven motor of escherichia coli.	bacterial flagella are powered by a motor that converts a transmembrane electrochemical potential of either h(+) or na(+) into mechanical work. in escherichia coli, the mota and motb proteins form the stator and function in proton translocation, whereas the flig protein is located on the rotor and is involved in flagellar assembly and torque generation. the sodium-driven polar flagella of vibrio species contain homologs of mota and motb, called poma and pomb, and also contain two other membrane ...	2000	10894732
use of rna arbitrarily primed-pcr fingerprinting to identify vibrio cholerae genes differentially expressed in the host following infection.	evidence suggests that a repertoire of vibrio cholerae genes are differentially expressed in vivo, and regulation of virulence factors in vivo may follow a different pathway. our work was aimed at characterization of in vivo-grown bacteria and identification of genes that are differentially expressed following infection by rna arbitrarily primed (rap)-pcr fingerprinting. the ligated rabbit ileal loop model was used. the motility of in vivo-grown bacteria increased by 350% over that of in vitro-g ...	2000	10858198
bacterial, viral and parasitic enteric pathogens associated with acute diarrhea in hospitalized children from northern jordan.	to determine the etiology of acute diarrhea in jordanian children under 5 years of age, we examined stool samples from 265 children admitted to the pediatric ward at princess rahma hospital for children, irbid, jordan, for parasites, rotavirus and enteric bacteria. using both traditional and molecular diagnostic techniques, we detected enteropathogens in 66.4% of patients with diarrhea. a single enteric pathogen was detected in 50.9% of the children, and multiple pathogens were detected in 15.5% ...	2000	10865179
cholera incidence and el niño-related higher ambient temperature.		2000	10865299
antibacterial activity of a chitooligosaccharide mixture prepared by cellulase digestion of shrimp chitosan and its application to milk preservation.	the antibacterial activity of a chitooligosaccharide mixture prepared by digestion of shrimp chitosan with cellulase at 50 degrees c for 14 h was evaluated. sugars with 1 to 8 degrees of polymer (dp) were found in this chitooligosaccharide mixture, and the weight percentage of sugars with dp > or = 6 was 44.3%. minimal lethal concentrations of this mixture against aeromonas hydrophila, escherichia coli, listeria monocytogenes, pseudomonas aeruginosa, salmonella typhimurium, shigella dysenteriae, ...	2000	10852568
functional analysis of genes in the rfb locus of leptospira borgpetersenii serovar hardjo subtype hardjobovis.	lipopolysaccharide (lps) is a key antigen in immunity to leptospirosis. its biosynthesis requires enzymes for the biosynthesis and polymerization of nucleotide sugars and the transport through and attachment to the bacterial membrane. the genes encoding these functions are commonly clustered into loci; for leptospira borgpetersenii serovar hardjo subtype hardjobovis, this locus, named rfb, spans 36.7 kb and contains 31 open reading frames, of which 28 have been assigned putative functions on the ...	2000	10858186
identification of a cho cell-elongating factor produced by vibrio cholerae o1.	vibrio cholerae strains with all known toxin genes deleted or inactivated still cause diarrhoea in some volunteers, suggesting the presence of an unknown virulence factor or factors. lysozyme-edta treated cells of jbk70, a genetically manipulated cholera toxin negative strain of vibrio cholerae o1, biotype el tor, release a factor that causes elongation of chinese hamster ovary (cho) cells. cho cell-elongating toxin (cef) was purified by fplc chromatography (anion exchange; q sepharose high perf ...	2000	10873485
virulence gene regulation inside and outside.	much knowledge about microbial gene regulation and virulence is derived from genetic and biochemical studies done outside of hosts. the aim of this review is to correlate observations made in vitro and in vivo with two different bacterial pathogens in which the nature of regulated gene expression leading to virulence is quite different. the first is vibrio cholerae, in which the concerted action of a complicated regulatory cascade involving several transcription activators leads ultimately to ex ...	2000	10874738
role and behaviour of the hydrophobic conditions in bacterial adhesion to incurrent siphon in a bivalve mollusc.	surface hydrophobicity is a widely distributed characteristic among human bacterial pathogens playing an important role in microbes retention by the incurrent siphon of a marine bivalve. feeding retention experiments with the bivalve mesodesma donacium was done with hydrophobic strains alone (staphylococcus aureus, salmonella paratyphi, vibrio cholerae) or with mixed cultures using a hydrophilic strain (aeromonas hydrophila). results showed that hydrophobic bacteria are retained in greater numbe ...	2000	10997493
delivery of protein antigens and dna by virulence-attenuated strains of salmonella typhimurium and listeria monocytogenes.	two different plasmid-vector systems were developed which allow the efficient production and presentation of protein antigens in antigen-presenting cells (apc) by means of virulence-attenuated bacteria. the first antigen-delivery system is based on the secretion machinery of the escherichia coli hemolysin (hlya-type i secretion system), which transports proteins, possessing the specific hlya secretion signal (hlya(s)) at the c-terminus, across both membranes of gram-negative bacteria. this syste ...	2000	11000455
activation, stimulation and uptake of bacterial ghosts in antigen presenting cells.	bacterial ghosts have been shown to be an innovative system to prepare vaccines of various bacteria with all features of the intact bacterial cell envelopes, especially all antigenic epitopes, but also to target recombinant proteins inserted in the cell envelopes of the ghost preparations to specific antigen presenting cells. to investigate the activation of the antigen presenting cell by bacterial ghosts in more detail we studied the uptake of bacterial ghosts in dendritic porcine cells and raw ...	2000	11000461
characterization and immunogenicity of vibrio cholerae ghosts expressing toxin-coregulated pili.	bacterial ghosts are attractive for use as non-living vaccines and as carriers of heterologous antigens of vaccine relevance. ghosts were prepared from vibrio cholerae strains of o1 or o139 serogroup after growth under culture conditions, which favor or repress the production of toxin-coregulated pili (tcp). immunoblotting confirmed the tcp status of these v. cholerae ghosts (vcg), which retained the cellular morphology and envelope sub-component profile of viable bacteria. rabbits were immunize ...	2000	11000467
detection of faecal leucocytes & erythrocytes from stools of cholera patients suggesting an evidence of an inflammatory response in cholera.	detection of faecal leucocytes and rbcs in stool samples of cholera patients has been reported in a small number of studies. this study extends these observations by examining stool samples of cholera patients in calcutta.	2000	11006654
vibrio cholerae o139 bengal: a descriptive study.	a prospective study was conducted to determine the clinical and laboratory characteristics and the clinical course of cholera due to vibrio cholerae o139 bengal. the study subjects included 22 adult males with stool culture-proven v. cholerae o139. on enrollment, mean +/- sd concentrations (mmol/l) of serum sodium, potassium, chloride, and bicarbonate were 134 +/- 3, 4 +/- 1, 102 +/- 4, and 13 +/- 4 respectively, and stool sodium, potassium, chloride, and bicarbonate concentrations were 120 +/- ...	2000	11014767
production of heat-labile enterotoxin by strains of aeromonas veronii bv veronii.	three isolates of aeromonas veronii bv veronii (2 environmental, one blood infection) were examined to see if they produce any enterotoxin and, if so, to determine its characteristics. two isolates caused fluid accumulation in the initial rabbit ileal loop tests. the other strain did so after a single passage through the rabbit ileal loop. all the isolates showed gradual enhancement of fluid secretion after each subsequent passage. inocula of 1 x 10(4) viable cells and 0.25 ml of culture filtrat ...	2000	11014770
class 1 integron-borne, multiple-antibiotic resistance encoded by a 150-kilobase conjugative plasmid in epidemic vibrio cholerae o1 strains isolated in guinea-bissau.	in the 1996-1997 cholera epidemic in guinea-bissau, surveillance for antimicrobial resistance showed the emergence of a multidrug-resistant strain of vibrio cholerae o1 during the course of the epidemic. the strain was resistant to ampicillin, erythromycin, tetracycline, furazolidone, aminoglycosides, trimethoprim, and sulfamethoxazole. concomitant with the emergence of this strain, we observed a resurgence in the number of registered cholera cases as well as an increase in the case fatality rat ...	2000	11015401
bacterial virulence gene regulation: an evolutionary perspective.	coevolution between bacteria and their plant or animal hosts determines characteristics of the interaction, the bacterial virulence genes involved, and the regulatory systems controlling expression of virulence genes. the long-standing association between salmonellae and their animal hosts has resulted in the acquisition by salmonella subspecies of a variety of virulence genes and the evolution of complex regulatory networks. the particular repertoire of virulence genes acquired by different sal ...	2000	11018137
detection of toxigenic vibrio cholerae from environmental water samples by an enrichment broth cultivation-pit-stop semi-nested pcr procedure.	a pit-stop semi-nested pcr assay for the detection of toxigenic vibrio cholerae in environmental water samples was developed and its performance evaluated. the pcr technique amplifies sequences within the cholera toxin operon specific for toxigenic v. cholerae. the pcr procedure coupled with an enrichment culture detected as few as four v. cholerae organisms in pure culture. treated sewage, surface, ground and drinking water samples were seeded with v. cholerae and following enrichment, a detect ...	2000	11021588
the vibrio cholerae o1 chromosomal integron.	until the discovery of the vibrio cholerae repeat (vcr), the gene capture and expression systems termed integrons had been typically associated with antibiotic-resistance gene cassettes with usually less than five genes in an array. a method is described for the cloning of the ends of large cassette arrays. conserved restriction sites within vcrs facilitated the mapping by southern hybridization and cloning of the 5' end of the vcr array, and using appropriate fragments it was possible to develo ...	2000	11021935
genetic relationships between clinical and environmental vibrio cholerae isolates based on multilocus enzyme electrophoresis.	a total of 107 isolates of vibrio cholerae, including 29 strains belonging to serogroup o139, were studied using multilocus enzyme electrophoresis (mlee) to determine allelic variation in 15 housekeeping enzyme loci. all loci were polymorphic and 99 electrophoretic types (ets) were identified from the total sample. no significant clustering of isolates was detected in the dendrogram generated from a matrix of coefficients of distances with respect to serogroup, biotype or country of isolation. t ...	2000	11021936
antisense pna effects in escherichia coli are limited by the outer-membrane lps layer.	antisense peptide nucleic acids (pnas) can inhibit escherichia coli gene expression and cell growth through sequence-specific rna binding, and this opens possibilities for novel anti-infective agents and tools for microbial functional genomics. however, the cellular effects of pnas are limited relative to effects in cell extracts, presumably because of cell barrier components such as the outer-membrane lipopolysaccharide (lps) layer or drug efflux pumps, both of which function to exclude antibio ...	2000	11021941
the vibrio cholerae toxr/tcpp/toxt virulence cascade: distinct roles for two membrane-localized transcriptional activators on a single promoter.	toxr is required in vibrio cholerae for transcriptional activation of the toxt gene, the protein product of which activates numerous genes involved in virulence. although toxr cannot activate the toxt promoter in escherichia coli, the products of the tcpph operon are shown here to activate the toxt promoter, and co-expression with toxrs enhances activation. an identical pattern was seen in a deltatcppdeltatoxr strain of v. cholerae when tcpph or toxrs was expressed from plasmids. although overex ...	2000	11029691
[molecular epidemiology of large bacterial endemics in sub-saharan africa].	over the past decades, the differentiation of bacterial strains for epidemiological purposes had been based on conventional phenotypic characters. more recently, methods studying the directly coded molecules or semantides (nucleic acids or proteins) have allowed, concomitantly with the technical progresses of electrophoresis, the description of stable, discriminant, reproducible markers, which were applicable to large series of isolates. initially applied to study nosocomial infections in indust ...	2000	11030062
in vivo covalent cross-linking of cellular actin by the vibrio cholerae rtx toxin.	enteric pathogens often export toxins that elicit diarrhea as a part of the etiology of disease, including toxins that affect cytoskeletal structure. recently, we discovered that the intestinal pathogen vibrio cholerae elicits rounding of epithelial cells that is dependent upon a gene we designated rtxa. here we investigate the association of rtxa with the cell-rounding effect. we find that v. cholerae exports a large toxin, rtx (repeats-in-toxin) toxin, to culture supernatant fluids and that th ...	2000	11032799
construction of a vibrio cholerae vaccine candidate using transposon delivery and flp recombinase-mediated excision.	recent efforts to develop a vaccine against the diarrheal disease cholera have focused on the use of live attenuated strains of the causative organism, vibrio cholerae. the ogawa lipopolysaccharide phenotype is expressed by many epidemic strains, and motility defects reduce the risk of reactive diarrhea in vaccine recipients. we therefore converted a motile inaba(+) vaccine candidate, peru-2, to a nonmotile ogawa(+) phenotype using a mariner-based transposon carrying rfbt, the gene required for ...	2000	11035750
construction and characterization of a nonproliferative el tor cholera vaccine candidate derived from strain 638.	in recent clinical assays, our cholera vaccine candidate strain, vibrio cholerae 638 el tor ogawa, was well tolerated and immunogenic in cuban volunteers. in this work we describe the construction of 638t, a thymidine auxotrophic version of improved environmental biosafety. in so doing, the thya gene from v. cholerae was cloned, sequenced, mutated in vitro, and used to replace the wild-type allele. except for its dependence on thymidine for growth in minimal medium, 638t is essentially indisting ...	2000	11035753
association of protease activity in vibrio cholerae vaccine strains with decreases in transcellular epithelial resistance of polarized t84 intestinal epithelial cells.	culture supernatants prepared from reactogenic strains of vibrio cholerae cause a decrease in the transcellular epithelial resistance of t84 intestinal cells. this decrease correlates with the presence of hemagglutinin/protease but not with the presence of other potential accessory toxins or proteases. these data suggest a possible role for hemagglutinin/protease in reactogenicity, although other factors may also contribute.	2000	11035765
a novel action of the proton pump inhibitor rabeprazole and its thioether derivative against the motility of helicobacter pylori.	the motility of helicobacter pylori was maximum at 37 degrees c and at ph 6. a newly developed proton pump inhibitor, rabeprazole (rpz), and its thioether derivative (rpz-th) markedly inhibited the motility of h. pylori. the concentrations of the drug necessary to inhibit 50% of the motility were 0.25, 16, 16, and >64 microgram/ml for rpz-th, rpz, lansoprazole, and omeprazole, respectively. no such inhibitory effects were observed with h(2) blockers or anti-h. pylori agents. the motilities of ca ...	2000	11036024
bactericidal activity of lemon juice and lemon derivatives against vibrio cholerae.	food products can be possible vectors of the agent responsible for cholera epidemics, because some of these products allow vibrio cholerae o1 to develop to concentrations above the dangerous level. this study deals with the behaviour of essential oils, natural and concentrated lemon juice and fresh and dehydrated lemon peel against v. cholerae o1 biotype eltor serotype inaba tox+. our aim was to evaluate whether these products, used at different dilutions, exhibit bactericidal or bacteriostatic ...	2000	11041258
active intestinal chloride secretion in human carriers of cystic fibrosis mutations: an evaluation of the hypothesis that heterozygotes have subnormal active intestinal chloride secretion.	to explain the very high frequency of cystic fibrosis (cf) mutations in most populations of european descent, it has been proposed that cf heterozygotes have a survival advantage when infected with vibrio cholerae or escherichia coli, the toxins of which induce diarrhea by stimulation of active intestinal chloride secretion. two assumptions underlie this hypothesis: (1) chloride conductance by the cf transmembrane conductance regulator (cftr) is the rate-limiting step for active intestinal chlor ...	2000	11055897
[experimental resistance of vibrio cholerae el tor to nalidixic acid and fluoroquinolones].	it was shown that sensitivity of vibrio cholerae eltor p-5879 to tetracycline, levomycetin, furazolidone, trimethoprim/sulfamethoxazole, aminoglycosides, beta-lactams, rifampicin, quinolones in vitro correlated with drugs efficacy in the treatment of experimental cholera of albino mice. mutants of v. cholerae eltor p-5879 nalr resistant to nalidixic acid (mic 160-200 mg/l) formed with frequency 10(-9)-110(-8) had no cross resistance to fluoroquinolones. but the efficacy of ofloxacin, lomefloxaci ...	2000	11057367
detection of virulence associated genes, haemolysin and protease amongst vibrio cholerae isolated in malaysia.	eighty-four strains of vibrio cholerae o1, o139 and non-o1/non-o139 from clinical and environmental sources were investigated for the presence of the toxin co-regulated pilus gene, tcpa, the virulence cassette genes ctxa, zot, ace and cep and also for their ability to elaborate haemolysin and protease. the ctxa and zot genes were detected using dna-dna hybridization while the ace, cep and tcpa genes were detected using pcr. production of haemolysin and protease was detected using mammalian eryth ...	2000	11057956
rapid method for species-specific identification of vibrio cholerae using primers targeted to the gene of outer membrane protein ompw.	the distribution of genes for an outer membrane protein (ompw) and a regulatory protein (toxr) in vibrio cholerae and other organisms was studied using respective primers and probes. pcr amplification results showed that all (100%) of the 254 v. cholerae strains tested were positive for ompw and 229 ( approximately 98%) of 233 were positive for toxr. none of the 40 strains belonging to other vibrio species produced amplicons with either ompw- or toxr-specific primers, while 80 bacterial strains ...	2000	11060082
emergence of vibrio cholerae o1 biotype el tor serotype inaba from the prevailing o1 ogawa serotype strains in india.	the toxigenic inaba serotype of vibrio cholerae o1 biotype el tor reappeared in india in 1998 and 1999, almost 10 years after its last dominance in calcutta in 1989. extensive molecular characterization by ribotyping, restriction fragment length polymorphism, and pulsed-field gel electrophoresis indicated that recent inaba strains are remarkably different from the earlier inaba strains but are very similar to the prevailing v. cholerae o1 ogawa el tor biotype strains. the antibiograms of the ina ...	2000	11060101
tetracycline resistant cholera in kelantan.	sensitivity testing on vibrio cholerae isolates during an epidemic in 1998 in kelantan identified strains resistant to tetracycline. this prompted a change in the usual management of cholera in kelantan. the antibiotic of choice was changed from tetracycline to erythromycin.	2000	11072502
inorganic polyphosphate in vibrio cholerae: genetic, biochemical, and physiologic features.	vibrio cholerae o1, biotype el tor, accumulates inorganic polyphosphate (poly p) principally as large clusters of granules. poly p kinase (ppk), the enzyme that synthesizes poly p from atp, is encoded by the ppk gene, which has been cloned from v. cholerae, overexpressed, and knocked out by insertion-deletion mutagenesis. the predicted amino acid sequence of ppk is 701 residues (81.6 kda), with 64% identity to that of escherichia coli, which it resembles biochemically. as in e. coli, ppk is part ...	2000	11073913
global spread of microorganisms by ships.		2000	11081499
human zonulin, a potential modulator of intestinal tight junctions.	intercellular tight junctions are dynamic structures involved in vectorial transport of water and electrolytes across the intestinal epithelium. zonula occludens toxin derived from vibrio cholerae interacts with a specific intestinal epithelial surface receptor, with subsequent activation of a complex intracellular cascade of events that regulate tight junction permeability. we postulated that this toxin may mimic the effect of a functionally and immunologically related endogenous modulator of i ...	2000	11082037
vibrio cholerae requires rpos for efficient intestinal colonization.	vibrio cholerae is a facultative intestinal pathogen that lives in aquatic environments, often in association with planktonic species. in the suckling mouse, oral inoculation with v. cholerae leads to intestinal colonization and symptoms of diarrheal disease. results reported here indicate a role for the alternative sigma factor, rpos, in intestinal colonization in this model of cholera. we constructed within rpos multiple independent mutations which consistently resulted in a fivefold decrease ...	2000	11083783
sequence analysis of tnphoa insertion sites in vibrio cholerae mutants defective in rugose polysaccharide production.	vibrio cholerae can switch from a smooth to a wrinkled or rugose colony phenotype characterized by the secretion of a polysaccharide that enables the bacteria to survive harsh environmental conditions. in order to understand the genetic basis of rugosity, we isolated tnphoa-induced stable, smooth mutants of two o1 el tor rugose strains and mapped the insertion sites in several of the mutants using a modified y-adapter pcr technique. one of the tnphoa insertions was mapped to the first gene of th ...	2000	11083805
phylogeny of vibrio cholerae based on reca sequence.	we sequenced a 705-bp fragment of the reca gene from 113 vibrio cholerae strains and closely related species. one hundred eighty-seven nucleotides were phylogenetically informative, 55 were phylogenetically uninformative, and 463 were invariant. not unexpectedly, vibrio parahaemolyticus and vibrio vulnificus strains formed out-groups; we also identified isolates which resembled v. cholerae biochemically but which did not cluster with v. cholerae. in many instances, v. cholerae serogroup designat ...	2000	11083852
ctx prophages in classical biotype vibrio cholerae: functional phage genes but dysfunctional phage genomes.	ctxphi is a filamentous, lysogenic bacteriophage whose genome encodes cholera toxin, the primary virulence factor produced by vibrio cholerae. ctx prophages in o1 el tor and o139 strains of v. cholerae are found within arrays of genetically related elements integrated at a single locus within the v. cholerae large chromosome. the prophages of o1 el tor and o139 strains generally yield infectious ctxphi. in contrast, o1 classical strains of v. cholerae do not produce ctxphi, although they produce ...	2000	11092860
monoclonal antibody ds6 detects a tumor-associated sialoglycotope expressed on human serous ovarian carcinomas.	a newly developed murine monoclonal antibody, ds6, immunohistochemically reacts with an antigen, ca6, that is expressed by human serous ovarian carcinomas but not by normal ovarian surface epithelium or mesothelium. ca6 has a limited distribution in normal adult tissues and is most characteristically detected in fallopian tube epithelium, inner urothelium and type 2 pneumocytes. pre-treatment of tissue sections with either periodic acid or neuraminidase from vibrio cholerae abolishes immunoreact ...	2000	11093807
cluster-analysis & patterns of dissemination of multidrug resistance among clinical strains of vibrio cholerae in calcutta, india.	antimicrobial resistance among vibrio cholerae has been monitored for several years in calcutta. to investigate the changing trends in multidrug resistance (mdr) among different serogroups of v. cholerae and to perform software assisted cluster analysis the current study was undertaken.	2000	11094852
an outbreak of eltor cholera in aizwal town of mizoram, india.	during the months of may, june and through early part of july 1994, an unusual occurrence of severe dehydrating watery diarrhoea cases and deaths were reported from aizwal town, the capital of mizoram, a north-eastern state of india. vibrio cholerae 01 biotype eltor, the causative agent responsible for this outbreak, was isolated from 50.0% of hospitalised cases. the disease affected older children and adults more (52.9%) than younger children below five years of age. vibrio cholerae 01 strains ...	2000	11407007
mechanical carrier of bacterial enteric pathogens by chrysomya megacephala (diptera: calliphoridae) in chiang mai, thailand.	chrysomya megacephala was studied regarding its mechanically bacterial carrier in urban areas of chiang mai, northern thailand. fifty-six adult flies were randomly collected using sweep insect net during april-may, 1999 from 3 fresh food markets and examined for bacteriological isolation. among them, 49 flies (87.5%) were bacterial carriers. the total 22 bacterial species and 8 groups were isolated. three species previously reported as the bacterial enteric pathogens causing diarrheal disease we ...	2000	11414447
year's comments for 2000.		2000	11334302
environmental cues and gene expression in porphyromonas gingivalis and actinobacillus actinomycetemcomitans.	microorganisms typically adapt to environmental cues by turning on and off the expression of virulence genes which, in turn, allows for optimal growth and survival within different environmental niches. this adaptation strategy includes sensing and responding to changes in nutrients, ph, temperature, oxygen tension, redox potential, microbial flora, and osmolarity. for a bacterium to adhere to, penetrate, replicate in, and colonize host cells, it is critical that virulence genes are expressed du ...	2000	11355267
[simultaneous detection and differentiation of o1 classical e1 tor, o139 and nono1 nono139 strains of vibrio cholerae by using multiplex pcr].	to explore the rapid and sensitive procedures for detection and differentiation of o1 classical(cvc), el tor(evc), o139 and nono1 nono139 strains of vibrio cholerae.	2000	11372395
regulation of intercellular tight junctions by zonula occludens toxin and its eukaryotic analogue zonulin.	the intestinal epithelium represents the largest interface between the external environment and the internal host milieu and constitutes the major barrier through which molecules can either be absorbed or secreted. there is now substantial evidence that tight junctions (tj) play a major role in regulating epithelial permeability by influencing paracellular flow of fluid and solutes. tj are one of the hallmarks of absorptive and secretory epithelia. evidence now exists that tj are dynamic rather ...	2000	11193578
modulation of intestinal permeability: a novel and innovative approach for the oral delivery of drugs, macromolecules and antigens.		2000	11255677
evaluation of synthetic schemes to prepare immunogenic conjugates of vibrio cholerae o139 capsular polysaccharide with chicken serum albumin.	vibrio cholerae serotype o139 is a new etiologic agent of epidemic cholera. there is no vaccine available against cholera caused by this serotype. v. cholerae o139 is an encapsulated bacterium, and its polysaccharide capsule is an essential virulent factor and likely protective antigen. this study evaluated several synthetic schemes for preparation of conjugates of v. cholerae o139 capsular polysaccharide (cps) with chicken serum albumin as the carrier protein (csa) using 1-ethyl-3(3-dimethylami ...	2000	11294508
reappearance of vibrio cholerae serogroup 0139 in yavatmal during june-august-1998.		2000	11271727
clinical profile of non-o1 strain-o139 of vibrio cholerae in the region of ambajogai, maharashtra.	to study clinical profile of the newly emerged novel strain non-o1, o139 of vibrio cholerae, in the region of ambajogai, district beed of maharashtra.	2000	11273144
improvements for multipurpose bacteriological identification tables to suit the diagnosis of vibrio cholerae.	the aim of the study was to reduce to key tests the 4 extensive polyvalent diagnostic biochemical tables most widely used in croatia and to adapt them for the demonstration of vibrio cholerae and its differentiation from the 3 vibrios (v. alvinolyticus, v. mentschikovii, v. fluvialis) important in differential diagnosis. the fourth table has now been adapted to differentiate among all 12 vibrio species known to be human pathogens (v. mimicus, v. cincinatiensis, v. holisae, v. damsela, v. furnisi ...	2000	11268787
live bacterial delivery systems for development of mucosal vaccines.	by expression of foreign antigens in attenuated strains derived from bacterial pathogens and in non-pathogenic commensal bacteria, recombinant vaccines are being developed that aim to stimulate mucosal immunity. recent advances in the pathogenesis and molecular biology of these bacteria have allowed rational development of new and improved bacterial carriers and more effective gene expression systems. these advances have improved the performance and versatility of these delivery systems to induc ...	2000	11249657
[cholera 1].		2000	11385767