Publications

vibrio cholerae vcib promotes iron uptake via ferrous iron transporters.	vibrio cholerae uses a variety of strategies for obtaining iron in its diverse environments. in this study we report the identification of a novel iron utilization protein in v. cholerae, vcib. the vcib gene and its linked gene, vcia, were isolated in a screen for v. cholerae genes that permitted growth of an escherichia coli siderophore mutant in low-iron medium. the vciab operon encodes a predicted tonb-dependent outer membrane receptor, vcia, and a putative inner membrane protein, vcib. vcib, ...	2008	18586940
proteomic analysis of vibrio cholerae in human stool.	an effective vaccine for vibrio cholerae is not yet available for use in the developing world, where the burden of cholera disease is highest. characterizing the proteins that are expressed by v. cholerae in the human host environment may provide insight into the pathogenesis of cholera and assist with the development of an improved vaccine. we analyzed the v. cholerae proteins present in the stools of 32 patients with clinical cholera. the v. cholerae outer membrane porin, ompu, was identified ...	2008	18591230
structure-function analysis of inositol hexakisphosphate-induced autoprocessing of the vibrio cholerae multifunctional autoprocessing rtx toxin.	vibrio cholerae secretes a large virulence-associated multifunctional autoprocessing rtx toxin (martx(vc)). autoprocessing of this toxin by an embedded cysteine protease domain (cpd) is essential for this toxin to induce actin depolymerization in a broad range of cell types. a homologous cpd is also present in the large clostridial toxin tcdb and recent studies showed that inositol hexakisphosphate (ins(1,2,3,4,5,6)p(6) or insp(6)) stimulated the autoprocessing of tcdb dependent upon the cpd (eg ...	2008	18591243
[vibrio cholerae serogroups o1 and o139: susceptibility to antibiotics during 7th cholera pandemic].	the review presents data on circulation of antibiotic resistant and susceptible strains of vibrio cholerae serogroups o1 and o139 isolated from cholera patients and healthy persons as well as from the environment, in asia, africa, australia, and europe (including new independent states) during 7th cholera pandemic.	2008	18595476
new qnr gene cassettes associated with superintegron repeats in vibrio cholerae o1.	a novel qnr determinant emerged in ciprofloxacin-resistant vibrio cholerae o1 from the amazon region of brazil. this qnrvc1 was in a typical class 1 integron. its attc showed 89% identity with v. parahaemolyticus superintegron repeats. analysis showed v. cholerae o1 carrying qnrvc2 associated with a v. cholerae superintegron repeat.	2008	18598639
vibrio porteresiae sp. nov., a diazotrophic bacterium isolated from a mangrove-associated wild rice (porteresia coarctata tateoka).	two facultatively anaerobic, nitrogen-fixing bacteria (strains mssrf30(t) and mssrf31) were isolated from a mangrove-associated wild rice (porteresia coarctata tateoka). these strains were determined to be nitrogen-fixers using the acetylene reduction assay and by pcr detection of a nifh gene amplicon. phylogenetic analyses based on 16s rrna gene sequences indicated that the novel strains were most closely related to vibrio fluvialis lmg 7894(t) (96.8 % gene sequence similarity), vibrio furnissi ...	2008	18599703
wings of the common house fly (musca domestica l.): importance in mechanical transmission of vibrio cholerae.	the importance of house fly (musca domestica l) wings in mechanical transmission of bacteria was studied. a droplet of phosphate-buffered saline containing vibrio cholerae was rolled along one wing of each house fly. none adhered to the wings but small proportions of the bacterium were isolated from about half the wings. vibrio cholerae was spread onto the ventral wing surfaces of each unconscious house fly which then was placed inside a bottle. when it regained consciousness, the types of activ ...	2008	18600198
determination of clonality and relatedness of vibrio cholerae isolates by genomic fingerprinting, using long-range repetitive element sequence-based pcr.	a high-throughput method which is applicable for rapid screening, identification, and delineation of isolates of vibrio cholerae, sensitive to genome variation, and capable of providing phylogenetic inferences enhances environmental monitoring of this bacterium. we have developed and optimized a method for genomic fingerprinting of v. cholerae based on long-range pcr. the method uses a primer set directed to enterobacterial repetitive intergenic consensus sequences, a high-fidelity dna polymeras ...	2008	18606790
mucosal penetration primes vibrio cholerae for host colonization by repressing quorum sensing.	to successfully infect a host and cause the diarrheal disease cholera, vibrio cholerae must penetrate the intestinal mucosal layer and express virulence genes. previous studies have demonstrated that the transcriptional regulator hapr, which is part of the quorum sensing network in v. cholerae, represses the expression of virulence genes. here, we show that hapr expression is also modulated by the regulatory network that governs flagellar assembly. specifically, flia, which is the alternative si ...	2008	18606988
lateral gene transfer of o1 serogroup encoding genes of vibrio cholerae.	in gram-negative bacteria, the o-antigen-encoding genes may be transferred between lineages, although mechanisms are not fully understood. to assess possible lateral gene transfer (lgt), 21 argentinean vibrio cholerae o-group 1 (o1) isolates were examined using multilocus sequence typing (mlst) to determine the genetic relatedness of housekeeping genes and genes from the o1 gene cluster. mslt analysis revealed that 4.4% of the nucleotides in the seven housekeeping loci were variable, with six di ...	2008	18616601
excess seqa leads to replication arrest and a cell division defect in vibrio cholerae.	although most bacteria contain a single circular chromosome, some have complex genomes, and all vibrio species studied so far contain both a large and a small chromosome. in recent years, the divided genome of vibrio cholerae has proven to be an interesting model system with both parallels to and novel features compared with the genome of escherichia coli. while factors influencing the replication and segregation of both chromosomes have begun to be elucidated, much remains to be learned about t ...	2008	18621898
high cell density fermentation of recombinant vibrio cholerae for the production of b subunit of escherichia coli enterotoxin.	high cell density fermentation studies were performed to produce the b subunit of escherichia coli heat-labile enterotoxin (ltb) from a vibrio cholerae culture that carries a recombinant plasmid with an ampicillin resistance gene, tac promoter, and the gene encoding ltb. upon induction with isopropyl-beta-d-thiogalactopyranoside (iptg) the culture secreted the protein into the extracellular milieu. fed-batch fermentation with stepwise addition of a total of 5 mm of iptg during the active growth ...	1995	18623144
bactericidal effect of lactoferrin and lactoferrin chimera against halophilic vibrio parahaemolyticus.	infections caused by vibrio parahaemolyticus, an halophilic member of the genus vibrio, have increased globally in the last 5 years. diarrhea caused by v. parahaemolyticus results from eating raw or undercooked seafood. the aim of this work was to investigate whether lactoferrin and some lactoferrin-peptides have bactericidal activity against vibrio parahaemolyticus atcc 17802, the pandemic strain o3:k6, and the multidrug resistant isolate 727, as well as against vibrio cholerae strains o1 and n ...	2009	18625283
overview of the inactivation by 254 nm ultraviolet radiation of bacteria with particular relevance to biodefense.	our goal was to ultimately predict the sensitivity of untested bacteria (including those of biodefense interest) to ultraviolet (uv) radiation. in this study, we present an overview and analysis of the relevant 254 nm data previously reported and available in the literature. the amount of variability in this data prevented us from determining an "average" response for any bacterium. therefore, we developed particular selection criteria to include the data in our analysis and suggested future gui ...	2008	18627518
functional independence of a variant luxopl91 from a non-o1 non-o139 vibrio cholerae over the activity of csra and fis.		2008	18628511
intra-family transmission of vibrio cholerae during a cholera epidemic in rural south-southern nigeria.		2008	18628554
cell harvesting by cross-flow microfiltration using a shear-enhanced module.	protein, produced by a bacterial culture of recombinant vibrio cholerae, was separated from cells in a fermentation broth by cross-flow microfiltration. a new, mechanically agitated (rotational) shear filter, the dmf(tm) filter from pall, was used to perform the separation. higher protein recovery and permeate flux than commonly obtained during cell harvesting were demonstrated using sixfold concentration followed by twofold diafiltration. the transmembrane pressure only increased by 10 kpa when ...	1996	18629909
polish up on past pestilence and present pathogens.	the cases presented here illustrate potential epidemic or pandemic events that once-silent pathogens portend. developing countries, where defenses are limited, are primary targets. of future concern are the developed countries that fail to use rigorous control measures established by the cdc, the who, and others to prevent the spread of infectious diseases. international travel has brought changes in demographics and a greater need for surveillance programs to control selective antibiotic resist ...	2008	18630097
abundance of sewage-pollution indicator and human pathogenic bacteria in a tropical estuarine complex.	studies on abundance and types of various pollution indicator bacterial populations from tropical estuaries are rare. this study was aimed to estimate current levels of pollution indicator as well as many groups of human pathogenic bacteria and their seasonal variations in different locations in mandovi and zuari rivers in the central west coast of india. the sampling covered the estuarine and upstream regions of these rivers representing premonsoon (may 2005), monsoon (september 2006) and post- ...	2009	18633722
motility and flagellin gene expression in the fish pathogen vibrio salmonicida: effects of salinity and temperature.	the success of several vibrio species, including vibrio cholerae, vibrio anguillarum and vibrio fischeri in colonizing their symbiont, or causing infection is linked to flagella-based motility. it is during early colonization or the initial phase of infection that motility appears to be critical. in this study we used vibrio salmonicida, a psychrophilic and moderate halophilic bacterium that causes cold-water vibriosis in seawater-farmed atlantic salmon (salmo salar), to study motility and expre ...	2008	18634865
riboswitches in eubacteria sense the second messenger cyclic di-gmp.	cyclic di-guanosine monophosphate (di-gmp) is a circular rna dinucleotide that functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes, including cell differentiation, conversion between motile and biofilm lifestyles, and virulence gene expression. however, the mechanisms by which cyclic di-gmp regulates gene expression have remained a mystery. we found that cyclic di-gmp in many bacterial species is sensed by a riboswitch class in messenger r ...	2008	18635805
molecular typing of vibrio cholerae o1 isolates from thailand by pulsed-field gel electrophoresis.	the aim of the present study was to genotypically characterize vibrio cholerae strains isolated from cholera patients in various provinces of thailand. two hundred and forty v. cholerae o1 strains, isolated from patients with cholera during two outbreaks, i.e. march 1999-april 2000 and december 2001-february 2002, in thailand, were genotypically characterized by noti digestion and pulsed-field gel electrophoresis (pfge). in total, 17 pfge banding patterns were found and grouped into four dice-co ...	2008	18637531
ballast water as a vector of coral pathogens in the gulf of mexico: the case of the cayo arcas coral reef.	the discharge of nutrients, phytoplankton and pathogenic bacteria through ballast water may threaten the cayo arcas reef system. to assess this threat, the quality of ballast water and presence of coral reef pathogenic bacteria in 30 oil tankers loaded at the pemex cayo arcas crude oil terminal were determined. the water transported in the ships originated from coastal, oceanic or riverine regions. statistical associations among quality parameters and bacteria were tested using redundancy analys ...	2008	18639903
putative virulence traits and pathogenicity of vibrio cholerae non-o1, non-o139 isolates from surface waters in kolkata, india.	vibrio cholerae non-o1, non-o139 was isolated from natural surface waters from different sites sampled in diarrhea endemic zones in kolkata, india. twenty-one of these isolates were randomly selected and included in the characterization. the multiserogroup isolates were compared by their virulence traits with a group of clinical non-o1, non-o139 isolates from the same geographic area. of the 21 environmental isolates, 6 and 14 strains belonged to heiberg groups i and ii, respectively. three of t ...	2008	18641168
atp negatively regulates the initiator protein of vibrio cholerae chromosome ii replication.	vibrio cholerae, the agent of cholera, has two circular chromosomes. in bacteria that contain a single chromosome, initiation of chromosome dna replication is mediated by dnaa, a aaa+ atpase that unwinds the origin of replication. there is little knowledge regarding initiation of chromosome replication in bacteria with more than one chromosome. here, we purified v. cholerae dnaa and rctb, which have been implicated in the replication of v. cholerae chromosome ii, and characterized their activiti ...	2008	18647828
investigation towards bivalent chemically defined glycoconjugate immunogens prepared from acid-detoxified lipopolysaccharide of vibrio cholerae o1, serotype inaba.	a free amino group present on the acid-detoxified lipopolysaccharide (pmlps) of v. cholerae o1 serotype inaba was investigated for site-specific conjugation. chemoselective pmlps biotinylation afforded the corresponding mono-functionalized derivative, which retained antigenicity. thus, pmlps was bound to carrier proteins using thioether conjugation chemistry. induction of an anti-lps antibody (ab) response in balb/c mice was observed for all conjugates. interestingly, the sera had vibriocidal ac ...	2009	18648931
trend of antibiotic resistance of vibrio cholerae strains from east delhi.	epidemics of cholera caused by toxigenic vibrio cholerae o1 and o139 (bengal strain) represent a major public health problem in most developing countries. in view of the reported shift in epidemiology and pattern of antibiotic resistance in this was study carried out to assess the development of resistance to essential drugs like fluoroquinolones during treatment of cholera and cholera like cases in delhi.	2008	18653912
simultaneous detection of six human diarrheal pathogens by using dna microarray combined with tyramide signal amplification.	multiplex pcr and dna microarray were combined with tyramide signal amplification (tsa) to develop a reliable method suitable for simultaneous detection of six species of human diarrheal pathogens (yersinia enterocolitica, shigella spp, salmonella typhi, brucella spp, vibrio cholera and escherichia coli o157:h7). meanwhile, our method could distinguish v. cholera serotype o1 from o139, and o157:h7 from o157: non-h7. this assay conferred a specificity of 100% for target pathogens. the limit of de ...	2008	18655810
a new variant of vibrio cholerae o1 el tor causing cholera in india.		2008	18657323
a cluster of vibrio cholerae o1 infections in french travelers to rajasthan (india), may 2006.	a woman aged 60 years was hospitalized for vibrio cholerae serogroup o1 cholera. twenty-six fellow travelers and 48 health care workers who cared for the patient were individually traced and contacted. of the 23/27 travelers with diarrhea during the trip, 4 presented antibodies. there was no person-to-person transmission.	2008	18666928
cholera, 2007.		2008	18668979
comparison of detection and signal amplification methods for dna microarrays.	one of the factors limiting the use of dna microarray technology for the detection of pathogenic organisms from clinical and environmental matrices has been inadequate assay sensitivity. to assess the effectiveness of post-hybridization secondary detection steps to enhance the sensitivity of dna microarray-based pathogen detection, we evaluated a panel of 11 commercial and novel hybridization detection and signal amplification methods (direct labeling, indirect aminoallyl labeling, antibody, dna ...	2008	18675897
the vibrio cholerae hybrid sensor kinase vies contributes to motility and biofilm regulation by altering the cyclic diguanylate level.	phosphorelay systems are important mediators of signal transduction during bacterial adaptation to new environments. previously we described the viesab operon, encoding a putative three-protein component phosphorelay involved in regulating vibrio cholerae virulence gene expression. at least part of the regulatory activity of viesab is exerted through the cyclic diguanylate (c-di-gmp)-degrading activity of the putative response regulator viea. so far no direct evidence that viesab encodes a phosp ...	2008	18676667
immunization with vibrio cholerae outer membrane vesicles induces protective immunity in mice.	the gram-negative bacterium vibrio cholerae releases outer membrane vesicles (omvs) during growth. in this study, we immunized female mice by the intranasal, intragastric, or intraperitoneal route with purified omvs derived from v. cholerae. independent of the route of immunization, mice induced specific, high-titer immune responses of similar levels against a variety of antigens present in the omvs. after the last immunization, the half-maximum total immunoglobulin titer was stable over a 3-mon ...	2008	18678672
a new vibrio cholerae srna modulates colonization and affects release of outer membrane vesicles.	we discovered a new small non-coding rna (srna) gene, vrra of vibrio cholerae o1 strain a1552. a vrra mutant overproduces ompa porin, and we demonstrate that the 140 nt vrra rna represses ompa translation by base-pairing with the 5' region of the mrna. the rna chaperone hfq is not stringently required for vrra action, but expression of the vrra gene requires the membrane stress sigma factor, sigma(e), suggesting that vrra acts on ompa in response to periplasmic protein folding stress. we also ob ...	2008	18681937
[distribution and molecular characteristics of vibrio cholerae serogroups o1 and o139 isolates in estuary of pearl river].	through systematic monitoring of the number and strain types of o1 and o139 vibrio cholerae in the pearl river estuary waters to analyze it's relevance with the temperature of environment, and the relevance between strains in water and isolates during outbreaks and epidemics as well as to estimate the methods used for environmental water detection and the potential role in cholera surveillance program.	2008	18686854
effectiveness and kinetics of ferrate as a disinfectant for ballast water.	this study examined whether ferrate could meet the international standards for successful ballast water treatment, including final concentrations of less than 1 cfu/ml of enterococci, less than 2.5 cfu/ml of escherichia coli, and less than 1 cfu/100 ml of vibrio cholerae. pure cultures of e. coli, klebsiella pneumoniae, and v. cholerae, and a mixed culture of enterococcus faecium and e. faecilis were grown in saline solution to simulate ballast water and were treated with dosages of ferrate rang ...	2008	18686931
acquisition of classical ctx prophage from vibrio cholerae o141 by el tor strains aided by lytic phages and chitin-induced competence.	the el tor biotype of vibrio cholerae o1, causing the current seventh pandemic of cholera, has replaced the classical biotype, which caused the sixth pandemic. the ctx prophages encoding cholera toxin in the two biotypes have distinct repressor (rstr) genes. recently, new variants of el tor strains that carry the classical type (ctx(class)) prophage have emerged. these "hybrid" strains apparently originate through lateral gene transfer and recombination events. to explore possible donors of the ...	2008	18689675
modulation of vibrio cholerae porin function by acidic ph.	the outer membrane of gram-negative bacteria contains porins, large pore-forming proteins which allow the traffic of hydrophilic compounds between the external medium and the periplasm. the oral mode of infection of vibrio cholerae, the agent of cholera, implies that the bacteria must adapt to severe changes in the environment, such as acidic ph and the presence of bile. because of their localization and the regulation of their expression in response to these external factors, the ompu and ompt ...	2007	18690017
contamination of community water sources by potentially pathogenic vibrios following sea water inundation.	potentially pathogenic members of the vibrionaceae family including vibrio cholerae and vibrio parahemolyticus were isolated from domestic sources of drinking water in coastal villages following sea water inundation during the tsunami in southern india. phenotypic and genotypic studies were done to confirm the identity and detection of toxins. vibrio-gyr (gyrase b gene) was detected in all sixteen vibrio isolates. toxin regulating genes i.e.: ctx gene, tdh gene, and trh gene, however were not de ...	2007	18697592
outbreak of cholera in a labour encampment in suburbs of a modern city in north india.		2007	18697595
identification and functional characterization of gene components of type vi secretion system in bacterial genomes.	a new secretion system, called the type vi secretion system (t6ss), was recently reported in vibrio cholerae, pseudomonas aeruginosa and burkholderia mallei. a total of 18 genes have been identified to be belonging to this secretion system in v. cholerae. here we attempt to identify presence of t6ss in other bacterial genomes. this includes identification of orthologous sequences, conserved motifs, domains, families, 3d folds, genomic islands containing t6ss components, phylogenetic profiles and ...	2008	18698408
antibacterial properties of fish mucus from channa punctatus and cirrhinus mrigala.	extracts and preparations made from the animal origin were used extensively in folk and modern medicine for treating many human diseases. in the present study efforts have been made to find the antimicrobial effect of the mucus of two bottom dwelling fresh water fishes namely, channa punctatus and cirrhinus mrigala. fish mucus were tested against ten pathogenic bacteria such as escherichia coli, klebsiella oxytoca, klebsiella pneumoniae, lactobacillus vulgaris, proteus mirabilis, pseudomonas aer ...	2008	18700685
crystal structures of c4-dicarboxylate ligand complexes with sensor domains of histidine kinases dcus and dctb.	two-component signaling systems allow bacteria to adapt to changing environments. typically, a chemical or other stimulus is detected by the periplasmic sensor domain of a transmembrane histidine kinase sensor, which in turn relays a signal through a phosphotransfer cascade to the cognate cytoplasmic response regulator. such systems lead ultimately to changes in gene expression or cell motility. mechanisms of ligand binding and signal transduction through the cell membrane in histidine kinases a ...	2008	18701447
inapparent infections and cholera dynamics.	in many infectious diseases, an unknown fraction of infections produce symptoms mild enough to go unrecorded, a fact that can seriously compromise the interpretation of epidemiological records. this is true for cholera, a pandemic bacterial disease, where estimates of the ratio of asymptomatic to symptomatic infections have ranged from 3 to 100 (refs 1-5). in the absence of direct evidence, understanding of fundamental aspects of cholera transmission, immunology and control has been based on ass ...	2008	18704085
essential genes in salmonella enteritidis as identified by tnaraout mutagenesis.	tnaraout is a mariner-based transposon containing an arabinose-inducible promoter p(bad) facing outward. tnaraout mutagenesis previously used to identify essential genes in vibrio cholerae can also be used to identify in vitro essential genes in salmonella enteritidis. a mutant screen was conducted based on the assumption that a mutant-harboring tnaraout insertion in the promoter region of an essential gene should exhibit arabinose-dependent growth phenotype. among five isolated mutants with suc ...	2008	18704577
class 1 integrons and sxt elements conferring multidrug resistance in vibrio cholerae o1 strains associated with a recent large cholera outbreak in orissa, eastern india.		2008	18706789
interplay between cyclic amp-cyclic amp receptor protein and cyclic di-gmp signaling in vibrio cholerae biofilm formation.	vibrio cholerae is a facultative human pathogen. the ability of v. cholerae to form biofilms is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. formation of mature biofilms requires the production of extracellular matrix components, including vibrio polysaccharide (vps) and matrix proteins. biofilm formation is positively controlled by the transcriptional regulators vpsr and vpst and is negatively regulated by the ...	2008	18708497
vibrio cholerae o139 multiple-drug resistance mediated by yersinia pestis pip1202-like conjugative plasmids.	a conjugative plasmid, pmrv150, which mediated multiple-drug resistance (mdr) to at least six antibiotics, including ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole, was identified in a vibrio cholerae o139 isolate from hangzhou, eastern china, in 2004. according to partial pmrv150 dna sequences covering 15 backbone regions, the plasmid is most similar to pip1202, an inca/c plasmid in an mdr yersinia pestis isolate from a madagascar bubonic ...	2008	18710912
bacterial exotoxins downregulate cathelicidin (hcap-18/ll-37) and human beta-defensin 1 (hbd-1) expression in the intestinal epithelial cells.	cathelicidin (hcap-18/ll-37) and beta-defensin 1 (hbd-1) are human antimicrobial peptides (amps) with high basal expression levels, which form the first line of host defence against infections over the epithelial surfaces. the antimicrobial functions owe to their direct microbicidal effects as well as the immunomodulatory role. pathogenic microorganisms have developed multiple modalities including transcriptional repression to combat this arm of the host immune response. the precise mechanisms a ...	2008	18717821
increased isolation of vibrio cholerae o1 serotype inaba over serotype ogawa in pakistan.	although the predominant vibrio cholerae serotype in pakistan is ogawa and serotype inaba is rare, there has been a significant increase in the isolation of inaba in our referral laboratory in karachi. this paper reports this observation and further analysis of previous cholera data from 1993 to 2005 to assess the trend of occurrence and resistance pattern of v. cholerae strains. from january to september 2005, 245/3292 (7.4%) specimens yielded growth of v. cholerae. of these, 243 were serotype ...	2008	18720620
cholera toxin-specific memory b cell responses are induced in patients with dehydrating diarrhea caused by vibrio cholerae o1.	infection with vibrio cholerae induces durable immunity against subsequent disease, a process hypothesized to reflect anamnestic immune responses at the intestinal mucosa. the presence of antigen-specific memory b cells may therefore be a more direct measure of protection than serum antibody responses.	2008	18729782
vibrio cholerae o1 from accra, ghana carrying a class 2 integron and the sxt element.	vibrio cholerae o1 from a 2006 outbreak in accra were commonly resistant to multiple antimicrobials and, in particular, to trimethoprim/sulfamethoxazole, drugs commonly used in the treatment of cholera. we sought to determine the genetic basis for trimethoprim/sulfamethoxazole resistance in outbreak isolates.	2008	18755696
[characterization of the adhesive activity of cholera vibrions in mammalian red blood cells as an additional test for assessment of their epidemic significance].	the in vitro study of the adhesive properties of v. cholerae eltor and v. cholerae o139 on a model of mammalian red blood cells revealed a correlation of their adhesive properties, the presence of the ctx ab, tcpa genes, and their hemolytic activity when blood group a (ii) red blood cells were used. in the latter case, the strains having the characteristics of ctx(+) tcp(+) hly(-) were ascertained to have a mean adhesive value (mav) of > 1.5, a red blood cell involvement coefficient (rbcic) of > ...	2008	18756736
[variation in the genome of ctxphi prophage of vibrio cholerae biovar el tor caused by tn5-mob transposon].	a key pathogenicity factor of the cholera etiologic agent is cholera toxin (ct) whose synthesis is encoded by the ctxab operon forming apart of the ctxphi ptophage. alterations in the virulent properties of the cholera vibrios are based on the variability of the ctxphi prophage containing the genes for ctxab, zot, ace, cep, orfu, and psh in its core region. at the same time, the mechanism of the porophage genome reorganization needs further and more profound analysis. the goal of this work was t ...	2008	18756818
the extracellular nuclease dns and its role in natural transformation of vibrio cholerae.	free extracellular dna is abundant in many aquatic environments. while much of this dna will be degraded by nucleases secreted by the surrounding microbial community, some is available as transforming material that can be taken up by naturally competent bacteria. one such species is vibrio cholerae, an autochthonous member of estuarine, riverine, and marine habitats and the causative agent of cholera, whose competence program is induced after colonization of chitin surfaces. in this study, we in ...	2008	18757542
comparison of distribution of virulence determinants in clinical and environmental isolates of vibrio cholera.	the virulence of a pathogenic vibrio cholerae is dependent on a discrete set of genetic determinants. in this study, we determined the distribution of virulence determinants among the clinical and environmental isolates of v. cholerae.	2008	18762819
construction of a trivalent candidate vaccine against shigella species with dna recombination.	in this work asd gene of shigella flexneri 2a strain t32 was replaced by vibrio cholerae toxin b subunit (ctxb) gene with dna recombination in vivo and in vitro. the resulting derivative of t32, designed as fwl01, could stably express ctxb, but its growth in lb medium depended on the presence of diaminopimelic acid (dap). then form i plasmid of shigella sonnei strain s7 was labeled with strain t32 asd gene and mobilized into fwl01. thus a trivalent candidate oral vaccine strain, designed as fsw0 ...	2002	18763059
a transient breach in the epithelial barrier leads to regulatory t-cell generation and resistance to experimental colitis.	previous studies have indicated that a defective epithelial barrier leads to inflammation of the underlying lamina propria. nevertheless, it is likely that physiologic breaks in the barrier must occur for homeostatic regulatory t cells to develop. we determined the effect of agents that disrupt epithelial tight junctions (ethanol and at1002, a vibrio cholerae zonula occludens toxin hexapeptide) on regulatory t-cell induction and resistance to induction of colitis by trinitrobenzene sulfonic acid ...	2008	18765239
intestinal adherence of vibrio cholerae involves a coordinated interaction between colonization factor gbpa and mucin.	the chitin-binding protein gbpa of vibrio cholerae has been recently described as a common adherence factor for chitin and intestinal surface. using an isogenic in-frame gbpa deletion mutant, we first show that v. cholerae o1 el tor interacts with mouse intestinal mucus quickly, using gbpa in a specific manner. the gbpa mutant strain showed a significant decrease in intestinal adherence, leading to less colonization and fluid accumulation in a mouse in vivo model. purified recombinant gbpa (rgbp ...	2008	18765724
preliminary x-ray diffraction analysis of yqjh from escherichia coli: a putative cytoplasmic ferri-siderophore reductase.	yqjh is a cytoplasmic fad-containing protein from escherichia coli; based on homology to viub of vibrio cholerae, it potentially acts as a ferri-siderophore reductase. this work describes its overexpression, purification, crystallization and structure solution at 3.0 a resolution. yqjh shares high sequence similarity with a number of known siderophore-interacting proteins and its structure was solved by molecular replacement using the siderophore-interacting protein from shewanella putrefaciens ...	2008	18765906
andrimid producers encode an acetyl-coa carboxyltransferase subunit resistant to the action of the antibiotic.	andrimid is a hybrid nonribosomal peptide-polyketide antibiotic that blocks the carboxyl-transfer reaction of bacterial acetyl-coa carboxylase (acc) and thereby inhibits fatty acid biosynthesis with submicromolar potency. the andrimid biosynthetic gene cluster from pantoea agglomerans encodes an admt gene with homology to the acetyl-coa carboxyltransferase (ct) beta-subunit gene accd. escherichia coli cells overexpressing admt showed resistance to andrimid. co-overproduction of admt with e. coli ...	2008	18768797
cholera toxin b accelerates disease progression in lupus-prone mice by promoting lipid raft aggregation.	infectious agents, including bacteria and viruses, are thought to provide triggers for the development or exacerbation of autoimmune diseases such as systemic lupus erythematosus in the genetically predisposed individual. molecular mimicry and engagement of tlrs have been assigned limited roles that link infection to autoimmunity, but additional mechanisms are suspected to be involved. in this study we show that t cells from lupus-prone mice display aggregated lipid rafts that harbor signaling, ...	2008	18768857
efficacy of partially hydrolyzed guar gum-added oral rehydration solution in the treatment of severe cholera in adults.	partially hydrolyzed guar gum (phgg) is a water-soluble fiber if added to oral rehydration solution (ors) and undergoes fermentation in the colon liberating short chain fatty acids (scfas). scfas potentiate the effect of ors, reducing the severity of diarrhea.	2008	18769066
detection, isolation, and identification of vibrio cholerae from the environment.	microbiological techniques for sampling the aquatic realm have become increasingly sophisticated, especially with advances in molecular biology. these techniques have been used to detect microorganisms that cannot be cultured by conventional bacteriological methods. this has resulted in a deeper and a clearer understanding of the ecology and epidemiology of microorganisms. important advances have been made in isolation, detection, and identification of vibrio cholerae over the past decade. the u ...	2006	18770592
clonal relationship among vibrio cholerae o1 el tor strains isolated in somalia.	one hundred and three vibrio cholerae o1 strains, selected to represent the cholera outbreaks which occurred in somalia in 1998-1999, were characterized by random amplified polymorphic dna patterns, ribotyping, and antimicrobial susceptibility. all strains showed a unique amplified dna pattern and 2 closely related ribotypes (b5a and b8a), among which b5a was the more frequently identified. ninety-one strains were resistant to ampicillin, chloramphenicol, spectinomycin, streptomycin, sulfamethox ...	2009	18774337
the bile response repressor brer regulates expression of the vibrio cholerae breab efflux system operon.	enteric pathogens have developed several resistance mechanisms to survive the antimicrobial action of bile. we investigated the transcriptional profile of vibrio cholerae o1 el tor strain c6706 under virulence gene-inducing conditions in the presence and absence of bile. microarray analysis revealed that the expression of 119 genes was affected by bile. the mrna levels of genes encoding proteins involved in transport were increased in the presence of bile, whereas the mrna levels of genes encodi ...	2008	18776020
transition state analogues in quorum sensing and sam recycling.	transition state structures can be derived from kinetic isotope effects and computational chemistry. molecular electrostatic potential maps of transition states serve as blueprints to guide synthesis of transition state analogue inhibitors of target enzymes. 5'- methylthioadenosine phosphorylase (mtap) functions in the polyamine pathway by recycling methylthioadenosine (mta) and maintaining cellular s-adenosylmethionine (sam). its transition state structure was used to guide synthesis of mt-dadm ...	2008	18776260
isolation, characterization and public health aspects of vibrio cholerae nag isolated from a danish duck farm.	the hygienic and pathogenic consequences of the isolation of vibrio cholerae nag from the conjunctiva of two ducklings, from brackish water samples in their surroundings, and from the intestinal contents of a duckling, are discussed in relation to present knowledge of the occurrence of vibrio cholerae nag in man and animals.	1975	18777317
severe diarrhea caused by cholera toxin-producing vibrio cholerae serogroup o75 infections acquired in the southeastern united states.	from 2003 through 2007, vibrio cholerae serogroup o75 strains possessing the cholera toxin gene were isolated from 6 patients with severe diarrhea, including 3 in georgia, 2 in alabama, and 1 in south carolina. these reports represent the first identification of v. cholerae o75 as a cause of illness in the united states. v. cholerae o75 was isolated from a water sample collected from a pond in louisiana in 2004. subsequently, 3 v. cholerae isolates from louisiana (2 from patients with diarrhea i ...	2008	18781876
role of the histone-like nucleoid structuring protein in the regulation of rpos and rpos-dependent genes in vibrio cholerae.	production of the zn-metalloprotease hemagglutinin (ha)/protease by vibrio cholerae has been reported to enhance enterotoxicity in rabbit ileal loops and the reactogenicity of live cholera vaccine candidates. expression of ha/protease requires the alternate sigma factor sigma(s) (rpos), encoded by rpos. the histone-like nucleoid structuring protein (h-ns) has been shown to repress rpos expression in escherichia coli. in v. cholerae strains of the classical biotype, h-ns has been reported to sile ...	2008	18790865
identification and characterization of cyclic diguanylate signaling systems controlling rugosity in vibrio cholerae.	vibrio cholerae, the causative agent of the disease cholera, can generate rugose variants that have an increased capacity to form biofilms. rugosity and biofilm formation are critical for the environmental survival and transmission of the pathogen, and these processes are controlled by cyclic diguanylate (c-di-gmp) signaling systems. c-di-gmp is produced by diguanylate cyclases (dgcs) and degraded by phosphodiesterases (pdes). proteins that contain ggdef domains act as dgcs, whereas proteins tha ...	2008	18790873
association of vibrio cholerae with plankton in coastal areas of mexico.	the el niño event of 1997/1998 provided an opportunity to carry out a field experiment in which the relationship of sea surface temperature and the association of vibrio cholerae with marine plankton could be assessed in mexican coastal and estuarine areas. plankton samples were collected from may 1997 through june 1999. sites included the mexican ports of veracruz, coatzacoalcos and frontera in the gulf of mexico and ensenada, guaymas, mazatlán, manzanillo, acapulco and oaxaca in the pacific oc ...	2009	18793311
effect of phage on the infectivity of vibrio cholerae and emergence of genetic variants.	seasonal epidemics of cholera in bangladesh are self-limited in nature, presumably due to phage predation of the causative vibrio cholerae during the late stage of an epidemic, when cholera patients excrete large quantities of phage in their stools. to further understand the mechanisms involved, we studied the effect of phage on the infectivity and survival of v. cholerae shed in stools. the 50% infectious dose of stool vibrios in infant mice was approximately 10-fold higher when the stools cont ...	2008	18794293
accommodation of gdp-linked sugars in the active site of gdp-perosamine synthase.	perosamine (4-amino-4,6-dideoxy- d-mannose), or its n-acetylated form, is one of several dideoxy sugars found in the o-antigens of such infamous gram-negative bacteria as vibrio cholerae o1 and escherichia coli o157:h7. it is added to the bacterial o-antigen via a nucleotide-linked version, namely gdp-perosamine. three enzymes are required for the biosynthesis of gdp-perosamine starting from mannose 1-phosphate. the focus of this investigation is gdp-perosamine synthase from caulobacter crescent ...	2008	18795799
influence of size, shape, and flexibility on bacterial passage through micropore membrane filters.	sterilization of fluids by means of microfiltration is commonly applied in research laboratories as well as in pharmaceutical and industrial processes. sterile micropore filters are subject to microbiological validation, where brevundimonas diminuta is used as a standard test organism. however, several recent reports on the ubiquitous presence of filterable bacteria in aquatic environments have cast doubt on the accuracy and validity of the standard filter-testing method. six different bacterial ...	2008	18800559
production of monoclonal antibodies specific to major outer membrane protein of edwardsiella tarda.	edwardsiella tarda is an important cause for hemorrhagic septicemia in fish and gastro and extra-intestinal infections in humans. monoclonal antibodies (mabs) were produced against outer membrane proteins (omps) of e. tarda et-7, isolated from diseased snakehead (ophiocephalus punctatus). two stable hybridoma clones, designated as 3f10 and 2c3 mabs were found to be potentially specific for e. tarda by indirect enzyme linked immunosorbent assay (elisa). these mabs recognized major immunogenic omp ...	2010	18804863
incidence of bacterial enteropathogens among hospitalized diarrhea patients from orissa, india.	bacteriological analysis of 1,551 stool/rectal swabs from all age groups of diarrhea patients of different hospitals of orissa from january 2004 to december 2006 was carried out using standard procedures. among all enteropathogens isolated in 886 culture-positive samples, escherichia coli constituted 75.5%, including 13.2% pathogenic e. coli; vibrio cholerae o1 constituted 17.3%; v. cholerae o139, 1%; shigella spp., 4.5% (shigella flexneri type 6, 2.9%, s. dysenteriae type i, 0.7%, s. sonnei, 0. ...	2008	18806340
vibrio cholerae flagellins induce toll-like receptor 5-mediated interleukin-8 production through mitogen-activated protein kinase and nf-kappab activation.	vaccine reactogenicity has complicated the development of safe and effective live, oral cholera vaccines. delta ctx vibrio cholerae mutants have been shown to induce inflammatory diarrhea in volunteers and interleukin-8 (il-8) production in cultured intestinal epithelial cells. bacterial flagellins are known to induce il-8 production through toll-like receptor 5 (tlr5). since the v. cholerae genome encodes five distinct flagellin proteins, flaa to flae, with homology to conserved tlr5 recognitio ...	2008	18809662
vibrio cholerae non-o1 infection in cirrhotics: case report and literature review.	vibrio species are ubiquitous in the marine environment and can cause severe infections in cirrhotic patients. patients with liver disease should be warned about the potential dangers of consuming raw or undercooked seafood, and avoiding exposure of wounds to seawater. we report a case of severe sepsis from vibrio cholerae non-o1 in a patient with cirrhosis awaiting orthotopic liver transplant. this case is aimed to advise clinicians about the importance of v. cholerae subtypes, and non-cholera ...	2009	18811633
epidemiological study of vibrio cholerae using variable number of tandem repeats.	by conventional genetic methods, including pulse-field gel electrophoresis and multilocus sequence typing, most pathogenic, cholera toxin-positive o1 and o139 isolates of vibrio cholerae cannot be distinguished. we evaluated relationships among 173 v. cholerae isolates collected between 1992 and 2007 from different geographic areas in india by analyzing five variable number of tandem repeat (vntr) loci. each vntr locus was highly variable, with between 5 and 19 alleles. eburst analysis revealed ...	2008	18811655
mechanisms of infectious diarrhea.	infectious diarrhea is an important public health problem worldwide. research has provided new insights into the mechanisms of diarrhea caused by various pathogens that are classified as noninflammatory, inflammatory or invasive. these three groups of organisms cause two diarrheal syndromes--noninflammatory diarrhea and inflammatory diarrhea. the noninflammatory diarrheas are caused by enterotoxin-producing organisms such as vibrio cholerae and enterotoxigenic escherichia coli, or by viruses tha ...	2008	18813221
secretory and gm1 receptor binding role of n-terminal region of ltb in vibrio cholerae.	heat labile enterotoxin from enterotoxigenic escherichia coli is similar to cholera toxin (ct) and is a leading cause of diarrhea in developing countries. it consists of an enzymatically active a subunit (lta) and a carrier pentameric b subunit (ltb). in the current study, we evaluated the importance of the n-terminal region of ltb by mutation analysis. deletion of the glutamine (deltaq3) residue and a substitution mutation e7g in the alpha1 helix region led to defects in ltb protein secretion. ...	2008	18814842
ftsk-dependent dimer resolution on multiple chromosomes in the pathogen vibrio cholerae.	unlike most bacteria, vibrio cholerae harbors two distinct, nonhomologous circular chromosomes (chromosome i and ii). many features of chromosome ii are plasmid-like, which raised questions concerning its chromosomal nature. plasmid replication and segregation are generally not coordinated with the bacterial cell cycle, further calling into question the mechanisms ensuring the synchronous management of chromosome i and ii. maintenance of circular replicons requires the resolution of dimers creat ...	2008	18818731
[prevalence of type iii secretion system genes in cholera vibrios from different serogroups].	prevalence of vcs genes coding the type iii secretion system (t3ss) in cholera vibrios of different serogroups isolated in russia and neighboring countries was studied for the first time. virulent strains of o1 and o139 serogroups as well as toxigenic vibrio cholerae strains of other serogroups contained no t3ss genes. unlike mentioned strains, 29.2% of atoxigenic non o1/non o139 cholera vibrios isolated from patients in russia and neighboring countries contained the t3ss genes cluster, which mi ...	2008	18819403
[virulence of pre-ctxphi-carrying vibrio cholerae: genotypic and phenotypic characteristics].	complex assessment of virulence of cholera vibrios carrying the truncated ctx element (pre-ctxphi prophage).	2008	18819404
controlled expression of cholera toxin b subunit from vibrio cholerae in escherichia coli.	the ctxb gene, the causative agent of cholera epidemic was successfully cloned from v. cholerae in e. coli. the insertion of the gene was confirmed by pcr as well as restriction digestion analyses. the sequencing results for the gene confirmed that the insert was in the correct orientation and in-frame with the p(bad) promoter and it showed that the gene was 99% homologous to the published ctxb sequence. the ctb protein was successfully expressed in e. coli using the pbad/his vector system. the ...	2008	18819625
covalent binding of flavins to rnfg and rnfd in the rnf complex from vibrio cholerae.	enzymes of the rnf family are believed to be bacterial redox-driven ion pumps, coupling an oxidoreduction process to the translocation of na+ across the cell membrane. here we show for the first time that rnf is a flavoprotein, with fmn covalently bound to threonine-175 in rnfg and a second flavin bound to threonine-187 in rnfd. rnf subunits d and g are homologous to subunits b and c of na+-nqr, respectively. each of these na+-nqr subunits includes a conserved s(t)gat motif, with fmn covalently ...	2008	18831535
mechanism of action of zot-derived peptide at-1002, a tight junction regulator and absorption enhancer.	tight junctions (tjs) are intercellular structures that control paracellular permeability and epithelial polarity. it is now accepted that tjs are highly dynamic structures that are regulated in response to exogenous and endogenous stimuli. here, we provide details on the mechanism of action of at-1002, the active domain of vibrio cholerae's second toxin, zonula occludens toxin (zot). at-1002, a hexamer peptide, caused the redistribution of zo-1 away from cell junctions as seen by fluorescence m ...	2009	18832018
riboflavin is an active redox cofactor in the na+-pumping nadh: quinone oxidoreductase (na+-nqr) from vibrio cholerae.	here we present new evidence that riboflavin is present as one of four flavins in na+-nqr. in particular, we present conclusive evidence that the source of the neutral radical is not one of the fmns and that riboflavin is the center that gives rise to the neutral flavosemiquinone. the riboflavin is a bona fide redox cofactor and is likely to be the last redox carrier of the enzyme, from which electrons are donated to quinone. we have constructed a double mutant that lacks both covalently bound f ...	2008	18832377
macrophage migration inhibitory factor plays a role in the regulation of microfold (m) cell-mediated transport in the gut.	it has been shown previously that certain bacteria rapidly (3 h) up-regulated in vivo microfold cell (m cell)-mediated transport of ag across the follicle-associated epithelium of intestinal peyer's patch. our aim was to determine whether soluble mediators secreted following host-bacteria interaction were involved in this event. a combination of proteomics and immunohistochemical analyses was used to identify molecules produced in the gut in response to bacterial challenge in vivo; their effects ...	2008	18832726
a comparison of clinical and immunologic features in children and older patients hospitalized with severe cholera in bangladesh.	: infection with vibrio cholerae induces protection from subsequent severe disease, suggesting that an effective vaccine could be an important preventive strategy. available vaccines provide less protection against cholera than natural infection, particularly in children.	2008	18833030
a novel dna microarray for rapid diagnosis of enteropathogenic bacteria in stool specimens of patients with diarrhea.	a microarray technique for the detection and identification of enteropathogenic bacteria at the species and subspecies levels was developed in this study, and the target bacteria included pathogenic escherichia coli, vibrio cholerae, vibrio parahaemolyticus, salmonella enterica, campylobacter jejuni, shigellae, yersinia enterocolitica, and listeria monocytogenes. the virulence gene of each pathogen was chosen as the amplification target, labeled with a fluorescence dye by multiplex polymerase ch ...	2008	18834908
bacterial enteropathogens of neonates admitted to an urban diarrhoeal hospital in bangladesh.	data on the aetiology of diarrhoea in neonates are scarce, especially from developing countries including bangladesh. a retrospective review of the electronic database of the microbiology laboratory of the international centre for diarrhoeal disease research, bangladesh (icddr,b), was carried out to examine enteropathogens associated with diarrhoea in neonates. stool specimens of the neonates on admission to the dhaka hospital of icddr,b were collected and sent to the laboratory for direct plati ...	2009	18840632
an outbreak of cholera among migrants living in a thai-myanmar border area.	to study epidemiologic characteristics of a cholera outbreak involving mainly myanmar migrants living in overcrowded conditions with poor sanitation in a thai-myanmar border district, in 2007.	2008	18843875
[clone and express ctb-stx2b fusion gene in enterohemrrhagic escherichia coli o157:h7 shigeal toxin 2b subunit and v cholera toxin b subunit and the detection of their immunogenicity].	to clone and express the fusion gene encoding enterohemrrhagic escherichia coli o157 : h7 (ehec o157 : h7) shigela toxin 2b subunit (stx2b) and vibrio cholera toxin b subunit (ctb) as well as to detect the immunogenicity and gm1-binding ability of fusion protein.	2008	18843998
small molecule-induced allosteric activation of the vibrio cholerae rtx cysteine protease domain.	vibrio cholerae rtx (repeats in toxin) is an actin-disrupting toxin that is autoprocessed by an internal cysteine protease domain (cpd). the rtx cpd is efficiently activated by the eukaryote-specific small molecule inositol hexakisphosphate (insp6), and we present the 2.1 angstrom structure of the rtx cpd in complex with insp6. insp6 binds to a conserved basic cleft that is distant from the protease active site. biochemical and kinetic analyses of cpd mutants indicate that insp6 binding induces ...	2008	18845756
vibrio vulnificus rtx toxin plays an important role in the apoptotic death of human intestinal epithelial cells exposed to vibrio vulnificus.	during vibrio vulnificus infection, v. vulnificus reaches the intestine and then invades the bloodstream by crossing the intestinal mucosal barrier of the host, which results in systemic septicemia. previously, we reported that the rtxa toxin secreted through the rtxe transporter contributes to the cytotoxicity of v. vulnificus against intestinal epithelial cells. here, we used gene mutants of rtxe and rtxa to determine the role that v. vulnificus rtxa toxin plays in the apoptotic death of human ...	2008	18849006
genetic analysis of vibrio cholerae monolayer formation reveals a key role for deltapsi in the transition to permanent attachment.	a bacterial monolayer biofilm is a collection of cells attached to a surface but not to each other. monolayer formation is initiated when a bacterial cell forms a transient attachment to a surface. while some transient attachments are broken, others transition into the permanent attachments that define a monolayer biofilm. in this work, we describe the results of a large-scale, microscopy-based genetic screen for vibrio cholerae mutants that are defective in formation of a monolayer biofilm. thi ...	2008	18849423
flexibility of vibrio cholerae toxt in transcription activation of genes having altered promoter spacing.	cholera, a severe diarrheal disease, is caused by ingestion of the gram-negative bacterium vibrio cholerae. expression of v. cholerae virulence factors is highly regulated at the transcriptional and posttranscriptional levels by a complex network of proteins and small noncoding rnas. the direct activator of transcription of most v. cholerae virulence genes is the toxt protein. toxt binds to a 13-bp sequence, the toxbox, located upstream of genes in its regulon. however, the organization of toxbo ...	2008	18849430