Publications

genetic detoxification of bacterial toxins.		2003	12958454
stimulation of mucosal immunity.		2003	12958460
identifying and subtyping species of dangerous pathogens by automated ribotyping.	an investigation of dangerous bacterial pathogens was conducted to determine the usefulness of automated rrna operon ribotyping (riboprinter system) to identify species. a total of 26 isolates comprising bacillus anthracis, brucella spp., burkholderia mallei, francisella tularensis, and yersinia pestis were tested using restriction endonucleases ecori, psti, pvuii and asei. the main problem was that the system's database-relying on ecori as restriction enzyme-does not contain the essential dange ...	2003	12967744
conjugating low molecular mass carbohydrates to proteins. 2. recovery of excess ligand used in the conjugation reaction.		2003	12968362
efficacy and tolerability of racecadotril in the treatment of cholera in adults: a double blind, randomised, controlled clinical trial.	the enkephalins, endogenous opiate substances, act as neurotransmitters along the entire digestive tract where they elicit intestinal antisecretory activity without affecting intestinal transit time or motility. racecadotril, through inhibition of enkephalinase, reinforces the physiological activity of endogenous enkephalins and, therefore, shows intestinal antisecretory activity.	2003	12970133
use of telemedicine in evading cholera outbreak in mahakumbh mela, prayag, up, india: an encouraging experience.	telemedicine (tm) services a process in which expert medical advice from afar is provided using electronic signals to transfer the medical data from one site to another. as a pilot project to assess the efficacy of tm in developing countries like india, a telemedicine center was set up at the main hospital of mahakumbh mela--a grand religious fair, at prayag, a city in north india. the daily reporting of the in-patient and outpatient cases at the fair revealed a surge of diarrhea cases among the ...	2003	12699612
class i integrons and sxt elements in el tor strains isolated before and after 1992 vibrio cholerae o139 outbreak, calcutta, india.	we examined the distribution of class i integrons and sxt elements in vibrio cholerae o1 el tor strains, isolated in calcutta, india, before and after the v. cholerae o139 outbreak in 1992. class i integrons, with aada1 gene cassette, were detected primarily in the pre-o139 strains; the sxt element was found mainly in the post-o139 strains.	2003	12702236
a constitutively active variant of the quorum-sensing regulator luxo affects protease production and biofilm formation in vibrio cholerae.	vibrio cholerae normally inhabits aquatic habitats but can cause a severe diarrheal illness in humans. its arsenal of virulence factors includes a secreted hemagglutinin (ha) protease. an ha protease-deficient mutant of v. cholerae was isolated and designated e7946 mpc. e7946 mpc was found to contain a point mutation in the luxo quorum-sensing regulator. in accordance with this finding, e7946 mpc exhibits a defect in quorum sensing. the mutant luxo allele [luxo(con)] produces a protein with a le ...	2003	12704130
vibrio cholerae o139 bengal: odyssey of a fortuitous variant.	vibrio cholerae o139, the new serogroup associated with epidemic cholera, came into being in the second half of the year 1992 in an explosive fashion and was responsible for several outbreaks in india and other neighbouring countries. this was an unprecedented event in the history of cholera and the genesis of the o139 serogroup was, at that time, thought to be the beginning of the next or the eighth pandemic of cholera. however, with the passage of time, the o1 serogroup of the el tor biotype a ...	2003	12706446
enhanced mucosal and systemic immune responses to a vaginal vaccine coadministered with rantes-expressing plasmid dna using in situ-gelling mucoadhesive delivery system.	to develop more potent and convenient mucosal vaccines, we investigated the effect of an in situ-gelling mucoadhesive vaginal vaccine delivery system and a genetic chemokine adjuvant on the local and systemic immune responses. the in situ-gelling mucoadhesive delivery system of hepatitis b surface antigen (hbsag), composed of poloxamers and polycarbophil, showed the prolonged retention at the vaginal tissues. following intravaginal administration to mice, hbsag-specific iga was induced in the va ...	2003	12706687
characterization of a vibrio cholerae phage isolated from the coastal water of peru.	a vibrio cholerae bacteriophage, family myoviridae, was isolated from seawater collected from the coastal water of lima, peru. genome size was estimated to be 29 kbp. the temperate phage was specific to v. cholerae and infected 12/13 v. cholerae o1 strains and half of the four non-o1/non-o139 strains tested in this study. vibrio cholerae o139 strains were resistant to infection and highest infection rates were obtained in low nutrient media amended with nacl or prepared using seawater as diluent ...	2003	12713461
acute gastroenteritis in children : what role for antibacterials?	the aim of this article is to define the currently accepted role of antibacterials in the treatment of acute gastroenteritis in children. most cases of acute gastroenteritis in children are viral, self-limited, and need only supportive treatment. appropriate fluid and electrolyte therapy, with close attention to nutrition, remain central to therapy.antibacterial therapy serves as an adjunct, to shorten the clinical course, eradicate causative organisms, reduce transmission, and prevent invasive ...	2003	12716215
[vibrios (vibrio cholerae, v. parahaemolyticus, v. vulnificus)].		2003	12718054
[cholera].		2003	12718067
characterization of the novel factor paa involved in the early steps of the adhesion mechanism of attaching and effacing escherichia coli.	nonenterotoxigenic porcine escherichia coli strains belonging to the serogroup o45 have been associated with postweaning diarrhea in swine and adhere to intestinal epithelial cells in a characteristic attaching and effacing (a/e) pattern. o45 porcine enteropathogenic e. coli (pepec) strain 86-1390 induces typical a/e lesions in a pig ileal explant model. using tnphoa transposon insertion mutagenesis on strain 86-1390, we found a mutant that did not induce a/e lesions. the insertion was identifie ...	2003	12874331
antigen-specific immunoglobulin a antibodies secreted from circulating b cells are an effective marker for recent local immune responses in patients with cholera: comparison to antibody-secreting cell responses and other immunological markers.	gut-derived lymphocytes transiently migrate through the peripheral circulation before homing back to mucosal sites and can be detected using an elispot-based antibody secreting cell (asc) assay. alternatively, transiently circulating lymphocytes may be cultured in vitro, and culture supernatants may be assayed for antigen-specific responses (antibody in lymphocyte supernatant [als] assay). the als assay has not been validated extensively in natural mucosal infection, nor has the als response bee ...	2003	12874365
molecular cloning and characterization of an abc multidrug efflux pump, vcam, in non-o1 vibrio cholerae.	a gene responsible for multidrug resistance was cloned from the chromosomal dna of non-o1 vibrio cholerae nctc 4716 by using as a host drug-hypersensitive escherichia coli strain kam32, which lacks major multidrug efflux pumps. e. coli cells transformed with the gene showed elevated levels of resistance to a number of structurally dissimilar drugs, such as tetracycline, norfloxacin, ciprofloxacin, doxorubicin, daunomycin, 4',6-diamidino-2-phenylindole, and hoechst 33342. we determined the nucleo ...	2003	12878498
unfolding of vibrio cholerae hemolysin induces oligomerization of the toxin monomer.	vibrio cholerae hemolysin (hlya) is a pore-forming toxin that exists in two stable forms: a hemolytically active water-soluble monomer with a native molecular weight of 65,000 and a hemolytically inactive sds-stable heptamer with the configuration of a transmembrane diffusion channel. transformation of the monomer into the oligomer is spontaneous but very slow in the absence of interaction with specific membrane components like cholesterol and sphingolipids. in this report, we show that mild dis ...	2003	12878594
purification and characterization of three members of the photolyase/cryptochrome family blue-light photoreceptors from vibrio cholerae.	the sequence of vibrio cholerae genome revealed three genes belonging to the photolyase/cryptochrome blue-light photoreceptor family. the proteins encoded by the three genes were purified and characterized. all three proteins contain folate and flavin cofactors and have absorption peaks in the range of 350-500 nm. only one of the three, vcphr, is a photolyase specific for cyclobutane pyrimidine dimers. the other two are cryptochromes and were designated vccry1 and vccry2, respectively. mutation ...	2003	12878596
humoral immune response of carp (cyprinus carpio) induced by oral immunization with liposome-entrapped antigen.	to study the value of liposomes as carriers of antigens for oral vaccination in fish, humoral immune responses were analyzed after immunizing carp (cyprinus carpio) with liposome-entrapped bovine serum albumin (bsa) as a model antigen. oral immunization of bsa (100 microg)-containing liposomes that were stable in carp bile induced significant antibody responses against bsa in serum as well as in intestinal mucus and bile. by contrast, no serum antibody responses were observed when fish were oral ...	2003	12631523
vgj phi, a novel filamentous phage of vibrio cholerae, integrates into the same chromosomal site as ctx phi.	we describe a novel filamentous phage, designated vgj phi, isolated from strain sg25-1 of vibrio cholerae o139, which infects all o1 (classical and el tor) and o139 strains tested. the sequence of the 7,542 nucleotides of the phage genome reveals that vgj phi has a distinctive region of 775 nucleotides and a conserved region with an overall genomic organization similar to that of previously characterized filamentous phages, such as ctx phi of v. cholerae and ff phages of escherichia coli. the co ...	2003	13129939
in vivo evidence for tonb dimerization.	tonb, in complex with exbb and exbd, is required for the energy-dependent transport of ferric siderophores across the outer membrane of escherichia coli, the killing of cells by group b colicins, and infection by phages t1 and phi80. to gain insights into the protein complex, tonb dimerization was studied by constructing hybrid proteins from complete tonb (containing amino acids 1 to 239) [tonb(1-239)] and the cytoplasmic fragment of toxr which, when dimerized, activates the transcription of the ...	2003	13129945
reclassification of vibrio hollisae as grimontia hollisae gen. nov., comb. nov.	the taxonomic positions of three representative strains of vibrio hollisae (lmg 17719(t), lmg 21416 and lmg 21538) were investigated by means of 16s rdna sequences and phenotypic data. v. hollisae strains (genbank/embl accession nos aj514909-aj514911) shared 99.5 % 16s rdna sequence similarity, but had only 94.6 % similarity to their closest phylogenetic neighbour, enterovibrio norvegicus. 16s rdna sequence similarity of v. hollisae and vibrio cholerae was only 91 %. these results suggest that v ...	2003	13130058
the influence of his94 and pro149 in modulating the activity of v. cholerae dsba.	dsba is the primary catalyst of disulfide bond formation in the periplasm of gram-negative bacteria. numerous theoretical and experimental studies have been undertaken to determine the molecular mechanisms by which dsba acts as a potent oxidant, whereas the homologous cytoplasmic protein, thioredoxin, acts as a reductant. many of these studies have focused on the nature of the two residues that lie between the active-site cysteines. although these are clearly important, they are not solely respo ...	2003	13678522
a new dimer interface for an abc transporter.	the crystallization of msba, an atp-binding cassette (abc) transporter involved in the transport of lipid a in escherichia coli, provided a fascinating glimpse into the high-resolution structure of an abc transporter at 4.8 a. the e. coli crystal structure of msba reveals a dimer. although the structure of the msba monomer is consistent with the biochemistry of abc transporters, including the human multidrug resistance p-glycoprotein, the interface between the monomers in the msba dimer may not ...	2003	13678821
emergence of vibrio cholerae o139 in and around hyderabad.		2003	17643008
vibrionaceae from cases of acute diarrhoea and their antimicrobial sensitivity pattern - a five year prospective study.	over a five year period, stool samples were screened for vibrionaceae from cases of acute diarrhoea, to study their isolation rate and their antimicrobial sensitivity pattern. all the isolates were identified by standard laboratory techniques. a total of 323 species belonging to vibrionaceae were isolated from 4492 stool samples tested over five year period (1996-2000), giving a positivity rate of 7.2%. maximum isolation was during the months of may to august (62.5%). out of 323 isolates, vibrio ...	2003	17643020
repeatability and pattern recognition of bacterial fatty acid profiles generated by direct mass spectrometric analysis of in situ thermal hydrolysis/methylation of whole cells.	direct ci mass spectrometry profiling of fatty acid methyl esters (fames) from in situ thermal hydrolysis/methylation (thm) of whole bacterial cells with tetramethylammonium hydroxide (tmah) has been demonstrated as a potential method for real time and fieldable detection/identification of microorganisms. bacillus anthracis (ames), yersinia pestis (nair. kenya), vibrio cholerae (e1 tor), brucella melitensis (abortus wild) and francisella tularensis (lvs vaccine) were profiled by this method duri ...	2003	18968943
a structural basis for the mechanism of aspartate-beta-semialdehyde dehydrogenase from vibrio cholerae.	l-aspartate-beta-semialdehyde dehydrogenase (asadh) catalyzes the reductive dephosphorylation of beta-aspartyl phosphate to l-aspartate-beta-semialdehyde in the aspartate biosynthetic pathway of plants and micro-organisms. the aspartate pathway produces fully one-quarter of the naturally occurring amino acids, but is not found in humans or other eukaryotic organisms, making asadh an attractive target for the development of new antibacterial, fungicidal, or herbicidal compounds. we have determine ...	2003	12493825
the vibrio pathogenicity island-encoded mop protein modulates the pathogenesis and reactogenicity of epidemic vibrio cholerae.	epidemic vibrio cholerae possess the vpi (vibrio pathogenicity island) essential virulence gene cluster. the vpi is 41.2 kb in size and encodes 29 potential proteins, several of which have no known function. we show that the vpi-encoded orf4 is a predicted 34-kda periplasmic protein containing a zinc metalloprotease motif. v. cholerae seventh-pandemic (el tor) strain n16961 carrying an orf4 mutation showed no obvious difference relative to its parent in the production of cholera toxin and the to ...	2003	12496202
a 4-year study of the epidemiology of vibrio cholerae in four rural areas of bangladesh.	how vibrio cholerae spreads around the world and what determines its seasonal peaks in endemic areas are not known. these features of cholera have been hypothesized to be primarily the result of environmental factors associated with aquatic habitats that can now be identified. since 1997, fortnightly surveillance in 4 widely separated geographic locations in bangladesh has been performed to identify patients with cholera and to collect environmental data. a total of 5670 patients (53% <5 years o ...	2003	12508151
experimental verification of a sequence-based prediction: f(1)f(0)-type atpase of vibrio cholerae transports protons, not na(+) ions.	the membrane energetics of the intestinal pathogen vibrio cholerae involves both h(+) and na(+) as coupling ions. the sequence of the c subunit of v. cholerae f(0)f(1) atpase suggested that this enzyme is h(+) specific, in contrast to the results of previous studies on the na(+)-dependent atp synthesis in closely related vibrio spp. measurements of the ph gradient and membrane potential in membrane vesicles isolated from wild-type and deltaatpe mutant v. cholerae show that the f(1)f(0) atpase of ...	2003	12511516
x- and w-band epr and q-band endor studies of the flavin radical in the na+ -translocating nadh:quinone oxidoreductase from vibrio cholerae.	na(+)-nqr is the entry point for electrons into the respiratory chain of vibrio cholerae. it oxidizes nadh, reduces ubiquinone, and uses the free energy of this redox reaction to translocate sodium across the cell membrane. the enzyme is a membrane complex of six subunits that accommodates a 2fe-2s center and several flavins. both the oxidized and reduced forms of na(+)-nqr exhibit a radical epr signal. here, we present epr and endor data that demonstrate that, in both forms of the enzyme, the r ...	2003	12515529
genetic diversity of vibrio cholerae o1 in argentina and emergence of a new variant.	the genetic diversity of vibrio cholerae o1 strains from argentina was estimated by random amplified polymorphic dna (rapd) analysis and pulsed-field gel electrophoresis (pfge). twenty-nine isolates carrying the virulence genes ctxa, zot, ace, and tcpa appeared to represent a single clone by both typing methods; while 11 strains lacking these virulence genes exhibited several heterogeneous rapd and pfge patterns. among the last group, a set of isolates from the province tucumán showed a single r ...	2003	12517837
effect of the biologically active fragment of zonula occludens toxin, delta g, on the intestinal paracellular transport and oral absorption of mannitol.	many therapeutically active agents experience low bioavailability upon oral administration due to low permeability, low solubility, interaction with efflux transporters or first pass metabolism. in general, absorption enhancers are agents that can modulate the paracellular permeability of drugs, thus, potentially increasing oral bioavailability. the objective of this study was to examine the effect of the active fragment of zonula occludens toxin (zot), deltag, on the transport of a paracellular ...	2003	12527181
ctxphi-independent production of the rs1 satellite phage by vibrio cholerae.	the cholera toxin genes of vibrio cholerae are encoded by the filamentous phage, ctxphi. chromosomal ctxphi prophage dna is often found flanked by copies of a related genetic element designated rs1, and rs1 dna can be packaged into filamentous phage particles (designated rs1phi) by using the ctxphi morphogenesis genes. rs1phi is a satellite phage that further controls expression and dissemination of ctxphi. here we describe a ctxphi-independent mechanism for production of rs1phi. a nontoxigenic ...	2003	12529504
reduction of cholera in bangladeshi villages by simple filtration.	based on results of ecological studies demonstrating that vibrio cholerae, the etiological agent of epidemic cholera, is commensal to zooplankton, notably copepods, a simple filtration procedure was developed whereby zooplankton, most phytoplankton, and particulates >20 microm were removed from water before use. effective deployment of this filtration procedure, from september 1999 through july 2002 in 65 villages of rural bangladesh, of which the total population for the entire study comprised ...	2003	12529505
experience with registered mucosal vaccines.	most pathogens gain access to their host through mucosal surfaces. it is therefore desirable to develop vaccination strategies that lead to mucosal immune responses. ideally, a vaccine should be administered mucosally in order to elicit mucosal protection. several attenuated live viral and bacterial pathogens are registered as oral vaccines for human use, including the oral polio vaccine (sabin) as well as attenuated strains of salmonella typhi and vibrio cholerae. these attenuated bacterial liv ...	2003	12531339
zonula occludens toxin increases the permeability of molecular weight markers and chemotherapeutic agents across the bovine brain microvessel endothelial cells.	the purpose of this study was to examine the ability of zonula occludens toxin (zot) to reversibly open tight junctions in bovine brain microvessel endothelial cells (bbmecs) to enhance drug delivery via the paracellular pathway. transport across bbmec monolayers was examined for molecular weight markers and chemotherapeutic agents ([(14)c]sucrose, [(14)c]inulin, [(3)h]propranolol, [(3)h]doxorubicin, and [(14)c]paclitaxel) with zot (0.0-4.0 microg/ml). teer of monolayers was measured to assess e ...	2003	12532391
elucidation of the vibrio anguillarum genetic response to the potential fish probiont pseudomonas fluorescens ah2, using rna-arbitrarily primed pcr.	the antagonistic interaction between a potential fish probiont, pseudomonas fluorescens strain ah2, and its target organism, vibrio anguillarum, was investigated by studying the genetic response of the target organism when it was exposed to the antagonist. we compared the differential display of arbitrarily pcr-amplified gene transcripts in v. anguillarum serotype o1 when it was exposed to ah2 supernatant with the display of transcripts in nonexposed control cultures. growth of v. anguillarum wa ...	2003	12533458
piiictx, a predicted ctxphi minor coat protein, can expand the host range of coliphage fd to include vibrio cholerae.	ctxphi is a filamentous bacteriophage that encodes cholera toxin. ctxphi infection of its host bacterium, vibrio cholerae, requires the toxin-coregulated pilus (tcp) and the products of the v. cholerae tolqra genes. here, we have explored the role of orfu, a predicted ctxphi minor coat protein, in ctxphi infection. prior to the discovery that it was part of a prophage, orfu was initially described as an open reading frame of unknown function that lacked similarity to known protein sequences. bas ...	2003	12533480
emergence and evolution of vibrio cholerae o139.	the emergence of vibrio cholerae o139 bengal during 1992-1993 was associated with large epidemics of cholera in india and bangladesh and, initially, with a total displacement of the existing v. cholerae o1 strains. however, the o1 strains reemerged in 1994 and initiated a series of disappearance and reemergence of either of the two serogroups that was associated with temporal genetic and phenotypic changes sustained by the strains. since the initial emergence of the o139 vibrios, new variants of ...	2003	12538850
vibrio cholerae cytolysin is composed of an alpha-hemolysin-like core.	the enteric pathogen vibrio cholerae secretes a water-soluble 80-kd cytolysin, vibrio cholerae cytolysin (vcc) that assembles into pentameric channels following proteolytic activation by exogenous proteases. until now, vcc has been placed in a unique class of pore-forming toxins, distinct from paradigms such as staphyloccal alpha-hemolysin. however, as reported here, amino acid sequence analysis and three-dimensional structure modeling indicate that the core component of the vcc toxin is related ...	2003	12538902
pathogenic potential of environmental vibrio cholerae strains carrying genetic variants of the toxin-coregulated pilus pathogenicity island.	the major virulence factors of toxigenic vibrio cholerae are cholera toxin (ct), which is encoded by a lysogenic bacteriophage (ctxphi), and toxin-coregulated pilus (tcp), an essential colonization factor which is also the receptor for ctxphi. the genes for the biosynthesis of tcp are part of a larger genetic element known as the tcp pathogenicity island. to assess their pathogenic potential, we analyzed environmental strains of v. cholerae carrying genetic variants of the tcp pathogenicity isla ...	2003	12540588
determination of the transcriptome of vibrio cholerae during intraintestinal growth and midexponential phase in vitro.	vibrio cholerae is the etiologic bacterial agent of cholera, a severe diarrheal disease endemic in much of the developing world. the v. cholerae genome contains 3,890 genes distributed between a large and a small chromosome. although the large chromosome encodes the majority of recognizable gene products and virulence determinants, the small chromosome carries a disproportionate number of hypothetical genes. thus, little is known about the role of the small chromosome in the biology of this orga ...	2003	12552086
construction and characterisation of o139 cholera vaccine candidates.	the hemagglutinin/protease (ha/p) seems to be an attractive locus for the insertion of heterologous tags in live cholera vaccine strains. a deltactxphi spontaneous mutant derived from a pathogenic strain of o139 vibrio cholerae was sequentially manipulated to obtain hapa colon, two colons cela derivatives which were later improved in their environmental safety by means of a thya mutation. all the strains here obtained showed similar phenotypes in traits known to be remarkable for live cholera va ...	2003	12559810
an evaluation of current cholera treatment.	cholera, caused by vibrio cholerae o1 and o139, is characterised by profuse purging of watery stools, and vomiting and dehydration. the mainstay of therapy of cholera patients is rehydration with oral rehydration salt solution or intravenous ringer's lactate depending upon the degree of dehydration. antibiotics such as tetracycline, doxycycline, norfloxacin, ciprofloxacin and furazolidone may be used as an adjunct to rehydration therapy for severely purging cholera patients to reduce the rate of ...	2003	12562304
analysis of residues determining specificity of vibrio cholerae tonb1 for its receptors.	in gram-negative organisms, high-affinity transport of iron substrates requires energy transduction to specific outer membrane receptors by the tonb-exbb-exbd complex. vibrio cholerae encodes two tonb proteins, one of which, tonb1, recognizes only a subset of v. cholerae tonb-dependent receptors and does not facilitate transport through escherichia coli receptors. to investigate the receptor specificity exhibited by v. cholerae tonb1, chimeras were created between v. cholerae tonb1 and e. coli t ...	2003	12562789
roles of nhaa, nhab, and nhad na+/h+ antiporters in survival of vibrio cholerae in a saline environment.	vibrio cholerae, the causative agent of cholera, is a normal inhabitant of aquatic environments, where it survives in a wide range of conditions of ph and salinity. in this work, we investigated the role of three na+/h+ antiporters on the survival of v. cholerae in a saline environment. we have previously cloned the vc-nhaa gene encoding the v. cholerae homolog of escherichia coli. here we identified two additional antiporter genes, designated vc-nhab and vc-nhad, encoding two putative proteins ...	2003	12562793
identification and characterization of a vibrio cholerae gene, mbaa, involved in maintenance of biofilm architecture.	the formation of biofilms is thought to play a key role in the environmental survival of the marine bacterium vibrio cholerae. although the factors involved in v. cholerae attachment to abiotic surfaces have been extensively studied, relatively little is known about the mechanisms involved in the subsequent maturation of the biofilms. here we report the identification of a novel gene, which we have named mbaa (for maintenance of biofilm architecture), that plays a role in the formation and maint ...	2003	12562809
contribution of pila to competitive colonization of the squid euprymna scolopes by vibrio fischeri.	vibrio fischeri colonizes the squid euprymna scolopes in a mutualistic symbiosis. hatchling squid lack these bacterial symbionts, and v. fischeri strains must compete to occupy this privileged niche. we cloned a v. fischeri gene, designated pila, that contributes to colonization competitiveness and encodes a protein similar to type iv-a pilins. unlike its closest known relatives, vibrio cholerae msha and vcfa, pila is monocistronic and not clustered with genes associated with pilin export or ass ...	2003	12571000
biosynthesis of 2-acetamido-2,6-dideoxy-l-hexoses in bacteria follows a pattern distinct from those of the pathways of 6-deoxy-l-hexoses.	6-deoxy-l-hexoses have been shown to be synthesized from dtdp-d-glucose or gdp-d-mannose so that the gluco/galacto-configuration is converted into the manno/talo-configuration, and manno/talo is switched to gluco/galacto. our laboratory has been investigating the biosynthesis of 2-acetamido-2,6-dideoxy-l-hexoses in both gram-positive and gram-negative bacteria, and in a recent paper we described the biosynthesis of the talo (pneumosamine) and galacto (fucosamine) derivatives from udp-d-n-acetylg ...	2003	12575896
genesis of variants of vibrio cholerae o1 biotype el tor: role of the ctxphi array and its position in the genome.	the gene encoding cholera toxin, the principal virulence factor of vibrio cholerae, is encoded by a filamentous, lysogenic bacteriophage known as ctxphi. the genome of v. cholerae, the host for ctxphi, consists of two chromosomes, one large and one small. here, it is shown that localization and array of ctx prophage dna in either the large or small chromosome of v. cholerae is likely to be one of the reasons for the emergence of o1 biotype el tor variants isolated just before and after the v. ch ...	2003	12576583
infection-blocking genes of a symbiotic rhizobium leguminosarum strain that are involved in temperature-dependent protein secretion.	rhizobium leguminosarum strain rbl5523 is able to form nodules on pea, but these nodules are ineffective for nitrogen fixation. the impairment in nitrogen fixation appears to be caused by a defective infection of the host plant and is host specific for pea. a tn5 mutant of this strain, rbl5787, is able to form effective nodules on pea. we have sequenced a 33-kb region around the phage-transductable tn5 insertion. the tn5 insertion was localized to the 10th gene of a putative operon of 14 genes t ...	2003	12580282
toxigenic vibrio cholerae serogroup o141-associated cholera-like diarrhea and bloodstream infection in the united states.	toxigenic vibrio cholerae serogroup o141 has been associated with sporadic cholera-like diarrhea and bloodstream infection in the united states. consumption of seafood and proximity to the coast may increase the risk of infection. all v. cholerae isolates recovered from stool samples of patients with diarrhea or from a normally sterile site should be serogrouped and assessed for cholera toxin production. improved surveillance and case-control studies are needed to further characterize illness an ...	2003	12599062
toxr regulon of vibrio cholerae and its expression in vibrios shed by cholera patients.	toxigenic vibrio cholerae cause cholera, a severe diarrheal disease responsible for significant morbidity and mortality worldwide. two determinants, cholera enterotoxin (ct) and toxin coregulated pilus (tcp) are critical factors responsible for this organism's virulence. the genes for these virulence determinants belong to a network of genes (the toxr regulon) whose expression is modulated by transcriptional regulators encoded by the toxrs, tcpph, and toxt genes. to define the toxr regulon more ...	2003	12601157
membrane localization of the toxr winged-helix domain is required for tcpp-mediated virulence gene activation in vibrio cholerae.	toxr is a bitopic membrane protein that controls virulence gene expression in vibrio cholerae. its cytoplasmic domain is homologous to the winged helix-turn-helix ('winged helix') dna-binding/transcription activation domain found in a variety of prokaryotic and eukaryotic regulators, whereas its periplasmic domain is of ill-defined function. several genes in v. cholerae are regulated by toxr, but by apparently different mechanisms. whereas toxr directly controls the transcription of genes encodi ...	2003	12603748
maltodextrin-binding proteins from diverse bacteria and archaea are potent solubility enhancers.	escherichia coli maltose-binding protein (mbp) is frequently used as an affinity tag to facilitate the purification of recombinant proteins. an important additional attribute of mbp is its remarkable ability to enhance the solubility of its fusion partners. mbps are present in a wide variety of microorganisms including both mesophilic and thermophilic bacteria and archaea. in the present study, we compared the ability of mbps from six diverse microorganisms (e. coli, pyrococcus furiosus, thermoc ...	2003	12606030
the vibrio cholerae porins ompu and ompt have distinct channel properties.	numerous environmental signals regulate the production of virulence factors and the composition of the outer membrane of vibrio cholerae. in particular, bile promotes the toxr-dependent expression of the porin ompu. strains expressing solely ompu are more resistant to bile, are better able to colonize the intestine, and produce more cholera toxin than strains expressing solely the ompt porin. to gain some understanding in the physiological relevance and the molecular mechanism underlying these p ...	2003	12606562
filamentous phages linked to virulence of vibrio cholerae.	the pathogenicity of vibrio cholerae depends upon its production of two key virulence factors: the toxin co-regulated pilus (tcp), a colonization factor, and cholera toxin, an exotoxin. genes encoding both virulence factors were introduced into v. cholerae by horizontal gene transfer. the toxin genes are contained within the genome of ctxphi, an integrated filamentous phage identified in 1996. in the past few years, it has been shown that ctxphi relies on novel processes for phage dna integratio ...	2003	12615217
purification and renaturation of membrane neuraminidase from haemophilus parasuis.	haemophilus parasuis, which causes polyserositis, polysynovitis, meningitis, septicemia, and pneumonia in pigs, has emerged as an increasing problem in modern swine production systems. co-factors for and the pathogenesis of h. parasuis disease are not defined. one of the potential virulence factors of h. parasuis is its neuraminidase (sialidase). while purifying the h. parasuis neuraminidase from the membrane fraction, we developed a protocol to renature enzymatic activity after enzyme preparati ...	2003	12591209
rpod promoters in campylobacter jejuni exhibit a strong periodic signal instead of a -35 box.	we have used a hidden markov model (hmm) to identify the consensus sequence of the rpod promoters in the genome of campylobacter jejuni. the identified promoter consensus sequence is unusual compared to other bacteria, in that the region upstream of the tata-box does not contain a conserved -35 region, but shows a very strong periodic variation in the at-content and semi-conserved t-stretches, with a period of 10-11 nucleotides. the tata-box is in some, but not all cases, preceded by a tgx, simi ...	2003	12595250
genome sequence of vibrio parahaemolyticus: a pathogenic mechanism distinct from that of v cholerae.	vibrio parahaemolyticus, a gram-negative marine bacterium, is a worldwide cause of food-borne gastroenteritis. v parahaemolyticus strains of a few specific serotypes, probably derived from a common clonal ancestor, have lately caused a pandemic of gastroenteritis. the organism is phylogenetically close to v cholerae, the causative agent of cholera.	2003	12620739
comparative genomic analyses of the vibrio pathogenicity island and cholera toxin prophage regions in nonepidemic serogroup strains of vibrio cholerae.	two major virulence factors are associated with epidemic strains (o1 and o139 serogroups) of vibrio cholerae: cholera toxin encoded by the ctxab genes and toxin-coregulated pilus encoded by the tcpa gene. the ctx genes reside in the genome of a filamentous phage (ctxphi), and the tcpa gene resides in a vibrio pathogenicity island (vpi) which has also been proposed to be a filamentous phage designated vpiphi. in order to determine the prevalence of horizontal transfer of vpi and ctxphi among none ...	2003	12620865
potentiality of a new compound for in vitro differentiation between halophilic and non-halophilic vibrios.	sensitivity of 21 halophilic vibrios and 16 clinical isolates of non-halophilic vibrios was determined against a new possible antivibrio agent, a pyrimidine analogue, 4, 6-dimethylpyrimidine -2-thiol (4,6-dmpt). it appeared to be a vibriocidal agent, having a mean mic and mbc of 32 microg/ml for halophilic strains and 64 microg/ml for non-halophilic strains and an ld50 of 300 mg/kg body weight of mice. thus, 4,6-dmpt may help an in vitro distinction between halophilic and non-halophilic vibrios. ...	2002	12622188
[characterization of vibrio cholerae cultures isolated in foci of cholera in the city of kazan].	during the period of the registered outbreak of cholera in 2001 in kazan 171 v. cholerae cultures were isolated in the focus of the infection (from patients, carriers and 7 environmental objects). the use of the basic and additional tests, including the polymerase chain reaction, made it possible to establish the circulation of v. cholerae, phagovar 15, in the focus of the infection. the strain isolated from the water reservoir azino-1 in kazan was identical in its properties to the epidemically ...	2002	12506636
[obtaining diagnostic fluorescent monoclonal immunoglobulins against the v. cholerae 0139-serovar].	below is given a procedure of the obtaining diagnostic fluorescent monoclonal immunoglobulin to detect cholera vibrios of o139 serovar. while obtaining preparations it was managed to determine optimal ftts-mka ratio, duration of their conjugation, series of fluorochrome. test specimens of fluorescent monoclonal immunoglobulin provides intensive glow of v cholerae o139 cells in the working dilution 1:16-1:32. tests of diagnostic ftts-mka on the great number of homologic and heterologic strains sh ...	2002	12587559
antimicrobial potentiality of a phenothiazine group of antipsychotic drug-prochlorperazine.	the antipsychotic drug, prochlorperazine (pcp), was tested for its antimicrobial efficacy against 103 strains belonging to both gram positive and gram negative bacteria. the drug was found to possess maximum activity against staphylococcus aureus, vibrio cholerae and shigella spp. pcp was moderately active against e. coli but most of the strains belonging to bacillus spp, klebsiella spp, salmonella spp and lactobacillus spp were found to be resistant to this drug. the drug was tested for its mod ...	2002	12597553
synergistic effect of ayurvedic pearl preparation on enhancing effectiveness of antibiotics.	studies were carried out with ayurvedic preparations derived from pearl, which include preparations bhasma and pishti. the synergistic effect to reduce the dose of antibiotic was tested against e. coli the test bacterium with ampicillin antibiotic by bore well and disks diffusion methods. it was observed that pearl preparations do not show any antibacterial activity but when used at 200 microg/ml concentration with antibiotics, then even at sub-lethal dose, the antibiotic has effectively shown t ...	2002	12597554
[a cholera epidemic in dijibouti (may 2000-january 2001)].	the purpose of this report is to describe a cholera outbreak that occurred in the republic of djibouti from may 2000 to january 2001. because the somalian index cases involved were identified, this outbreak can be used as a model for imported epidemics. development of the disease in the djibouti city is promoted by a combination of poor living conditions and inadequate water supply. unlike in previous epidemics in djibouti, bacteriological study demonstrated the emergence of vibrio cholerae stra ...	2002	12616941
quinolone susceptibility of vibrio cholerae o1 & o139 isolates from vellore.	vellore is an endemic area for cholera. the relative prevalence of clinical cases of vibrio cholerae o1 and o139 has been fluctuating. few studies have examined the susceptibility of local isolates to quinolones. the objective of the present study was to look at quinolone susceptibility and determine mic of ciprofloxacin to representative clinical isolates of v. cholerae o1 and o139 in vellore, obtained between 1997 and 1999.	2002	12619447
information overload: assigning genetic functionality in the age of genomics and large-scale screening.	as more and more genome sequences are completed, it is becoming increasingly evident that our understanding of the function of most bacterial gene products is lacking. this is frustrating, particularly in the study of pathogens, where an understanding of the role of individual gene products would probably facilitate the development of novel antimicrobials and vaccines. recently, we devised a technique known as virulence-attenuated pool (vap) screening to help assign genetic functionality to gene ...	2002	12564993
comparison of sxt and r391, two conjugative integrating elements: definition of a genetic backbone for the mobilization of resistance determinants.	the sxt element (sxt) is becoming an increasingly prevalent vector for the dissemination of antibiotic resistances in vibrio cholerae. sxt is a member of a larger family of elements, formerly defined as incj plasmids, that are self-transmissible by conjugation and integrate site-specifically into the host chromosome. comparison of the dna sequences of sxt and r391, an incj element from providencia rettgeri, indicate that these elements consist of a conserved backbone that mediates the regulation ...	2002	12568332
[analysis of gene cluster of tat-dependent protein export system of vibrio cholerae and its function].	the tat (twin-arginine translocatin) system is a recently defined protein export pathway that serves to translocate folded proteins. the substrates of the tat pathway contain specific amino-terminal signal peptides that exhibit a conserved amino acid consensus motif-s/t-r-r-x-f-l-x. here is the report of knocked out the tata, tatb and tatc genes of the v. cholerae by suicide plasmid homologous recombination technology. mutant strains showed obvious changes of growth characteristics. the transpor ...	2002	12561481
enlightening cholera bug reveals new virulence system.		2002	12546909
[differences in virulence genes in vibrio cholerae eltor strains isolated from different sources in turkmenistan territory].	polymerase chain reaction (pcr) detected the presence of various genes associated with virulence in genome of strains v. cholerae eltor isolated in turkmenistan territory during epidemic and epidemic-free perios. it was found that a complete set of virulence genes (ctxa+, tcpa+ and toxr+) contained strains isolated from patients, carriers and environment only in cholera epidemics. strains isolated from the environment in the period free of epidemics did not contain ctxa and tcpa in 78.2% of case ...	2002	12534264
[hemolytic activity and toxigenicity of vibrio cholerae of different serogroups].	experimental data on the comparative evaluation of the hemolytic activity of ctx+ hly- and ctx- hly+ v. cholerae, serogroups o1 and o139, in the process of their cultivation in different nutrient media are presented. the capacity of ctx+ v. cholerae of both serogroups cultivated under the conditions of iron deficiency, for the production of hemolysin capable of lyzing sheep red blood cells was shown. hemolysin produced by ctx- strains of v. cholerae was synthesized under any conditions. the stud ...	2002	12524992
[morphology and enzyme activity of nonculturable forms of vibrio cholerae].	the transition of v. cholerae into the uncultivable state under experimental conditions was accompanied by gradual changes in their morphology, motility and metabolic activity. the vibrios took the oval form, lost their flagellum, motility and enzyme activity on diagnostic media. dehydrogenase activity tested by reduction of triphenyl tetrazolium chloride, increased at the initial stages and dropped to the initial level or even lower by the end of the observation period (10 months). similar dyna ...	2002	12524994
comparison of single-dose azithromycin and 12-dose, 3-day erythromycin for childhood cholera: a randomised, double-blind trial.	cholera is a major public-health problem, with children most affected. however, effective single-dose antimicrobial regimens have been identified only for adults. our aim was to compare the efficacy of azithromycin and erythromycin regimens in the treatment of children.	2002	12480424
drug sensitivity pattern of cholera in children.	to study the drug sensitivity pattern of cholera in children.	2002	12481672
the binding of synthetic analogs of the upstream, terminal residue of the o-polysaccharides (o-ps) of vibrio cholerae o:1 serotypes ogawa and inaba to two murine monoclonal antibodies (mabs) specific for the ogawa lipopolysaccharide (lps).	the binding of nineteen analogues of the upstream, terminal, monosaccharide residue of each of the o-polysaccharide (o-ps) of vibrio cholerae o:1, serotype ogawa and inaba, with two murine monoclonal igg antibodies both specific for the ogawa lps were measured using fluorescence spectroscopy. the use of the deoxy and the deoxyfluoro analogs allowed further refinement of the hydrogen-bonding pattern involved in the binding. based on the binding characteristics observed for some of the ligands in ...	2002	12493228
[variable tandem repeat vca of vibrio cholerae].	computer analysis revealed seven potential variable-number tandem-repeat (vntr) loci in the vibrio cholerae genome. specific primers were designed to amplify locus vca located on chromosome 2 and containing a tgctgt repeat. the locus was found in all tested strains from a v. cholerae strain collection, the repeat number varying 3 to 23. in total, 14 vca alleles were observed. the vca locus was proposed as a marker for the molecular typing of v. cholerae strains.	2002	12500547
enhanced permeability of molecular weight markers and poorly bioavailable compounds across caco-2 cell monolayers using the absorption enhancer, zonula occludens toxin.	zonula occludens toxin (zot), a protein elaborated from vibrio cholerae, has been shown to be capable of reversibly opening tight junctions. the objective of this work was to determine the stability of zot and to examine the permeability of a series of molecular weight hydrophilic markers and therapeutic agents in the presence of zot.	2002	12458674
involvement of in vivo induced chey-4 gene of vibrio cholerae in motility, early adherence to intestinal epithelial cells and regulation of virulence factors.	using a global transcription profile approach chey-4 of vibrio cholerae was identified as an in vivo induced gene. in the present study, duplication of the gene in the chromosome resulted in increased motility, increased chemotactic response towards isolated intestinal mucus layer and stronger adhesion to human intestinal epithelial cell line at an early phase of infection compared to wild type and a null mutant strain. in contrast to the chey-4 null mutant, duplication of chey-4 gene resulted i ...	2002	12459494
domestic cholera in germany associated with fresh fish imported from nigeria.		2002	12461596
alive but non-infectious.		2002	12467699
comparison of mucosal and systemic humoral immune responses after transcutaneous and oral immunization strategies.	in order to compare the ability of transcutaneous and oral immunization strategies to induce mucosal and systemic immune responses, we inoculated mice transcutaneously with cholera toxin (ct) or the non-toxic b subunit of cholera toxin (ctxb), or orally with peru2(petr1), an attenuated vaccine strain of vibrio cholerae expressing ctxb. in addition, we also evaluated dual immunization regimens (oral inoculation with transcutaneous boosting, and transcutaneous immunization with oral boosting) in a ...	2002	12034098
characterization of a toxigenic vibrio cholerae o139 strain belonging to a new ribotype and isolated from a diarrheal patient.	we characterized a vibrio cholerae o139 strain isolated from a diarrheal patient admitted to taluk hospital, cherthala, alleppey, kerala, india, on 9 june 2000. the v. cholerae o139 strain possesses the core of the ctx genetic element, colonization toxin-coregulated pilus, the adherence outer membrane protein, and the central regulatory protein encoded by toxr and produces cholera toxin (200 pg/ml). we provide molecular evidence showing that toxigenic v. cholerae o139 strain alo95 belongs to a d ...	2002	12454195
involvement of the hap gene (mucinase) in the survival of vibrio cholerae o1 in association with the blue-green alga, anabaena sp.	mucinase is a soluble haemagglutinin protease, which may be important for the survival of vibrio cholerae in association with mucilaginous blue-green algae (cyanobacteria). a comparative survival study was carried out with an anabaena sp. and a wild-type v. cholerae o1 strain hap+ gene (haemagglutinin-protease), together with its isogenic mutant hap (hap-deleted gene). a simple spread plate technique was followed to count culturable v. cholerae o1 on taurocholate tellurite gelatin agar plate. th ...	2002	12455611
comparative and genetic analyses of the putative vibrio cholerae lipopolysaccharide core oligosaccharide biosynthesis (wav) gene cluster.	we identified five different putative wav gene cluster types, which are responsible for the synthesis of the core oligosaccharide (os) region of vibrio cholerae lipopolysaccharide. preliminary evidence that the genes encoded by this cluster are involved in core os biosynthesis came from analysis of the recently released o1 el tor v. cholerae genome sequence and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of o1 el tor mutant strains defective in three genes (waaf, waal, and ...	2002	11953379
evidence for the emergence of non-o1 and non-o139 vibrio cholerae strains with pathogenic potential by exchange of o-antigen biosynthesis regions.	the novel epidemic strain vibrio cholerae o139 bengal originated from a seventh-pandemic o1 el tor strain by antigenic shift resulting from homologous recombination-mediated exchange of o-antigen biosynthesis (wb) clusters. conservation of the genetic organization of wb regions seen in other serogroups raised the possibility of the existence of pathogenic non-o1 and non-o139 v. cholerae strains that emerged by similar events. to test this hypothesis, 300 v. cholerae isolates of non-o1 and non- ...	2002	11953381
plasmidic extended-spectrum beta-lactamases in vibrio cholerae o1 el tor isolates in argentina.	since 1992 there have been seven major outbreaks of cholera in argentina. susceptibility analysis of 1,947 isolates (40% of reported cases) of vibrio cholerae o1 biotype el tor suggested the presence of extended-spectrum beta-lactamases (esbls) in 28 isolates. because of their different susceptibility profiles, v. cholerae isolates m1502, m1516, m1573, and m3030 (all of which are of the ogawa serotype) were selected for the present study. by susceptibility analysis, isoelectric focusing, and pcr ...	2002	11959583
ygbq, a cell division protein in escherichia coli and vibrio cholerae, localizes in codependent fashion with ftsl to the division site.	ygbq is a cell division protein in escherichia coli and vibrio cholerae. in e. coli the ygbq gene was discovered as a result of a computer search of the e. coli genome designed to find potential interacting partners for cell division protein ftsl. in v. cholerae, ygbq was identified as an essential gene by using a transposon that fuses genes to an arabinose promoter. the role of ygbq in cell division is supported by the following. cells depleted of ygbq in both organisms form long filaments, but ...	2002	11972052
a voyage of discovery: cholera, climate and complexity.		2002	11972615
binding site requirements of the virulence gene regulator aphb: differential affinities for the vibrio cholerae classical and el tor tcpph promoters.	the differential expression of virulence genes be-tween the two disease-causing biotypes of vibrio cholerae, classical and el tor, is primarily due to a single basepair change in the tcpph promoter, which strongly influences the ability of the lysr regulator aphb to activate transcription in response to environmental conditions. we show here that this single basepair change influences virulence gene expression by dramatically altering the affinity of aphb for its recognition site in the tcpph pr ...	2002	11972789
model of vibrio cholerae toxin coregulated pilin capable of filament formation.	a complete three-dimensional model (rcsb001169; pdb code 1qqz ) for the vibrio cholerae toxin coregulated pilus protein (tcpa), including residues 1-197, is presented. we have used the crystal structure of the neisseria gonorrhoeae pilin (pile), available biochemical data about tcpa, variations in the primary sequences of tcpa among various vibrio cholerae strains and secondary structure prediction, hydrophilicity, surface probability and antigenicity plots for tcpa to build our model. in our tc ...	2002	11983930
minor pilin subunits are conserved in vibrio cholerae type iv pili.	the nucleotide sequences of five open reading frames within the vibrio cholerae nagv14 type iv pilus gene cluster were determined. the genes showed high homology to the mannose-sensitive hemagglutinin (msha) pilus genes mshb, mshc, mshd, msho and mshp. pcr analysis showed that a msha-like gene cluster is highly conserved among different v. cholerae strains, with the exception of the previously reported major pilin subunit. recombinant mshb and msho proteins were purified and specific antiserum w ...	2002	11985966
effect of mild acid ph on the functioning of bacterial membranes in vibrio cholerae.	in this paper, we initiated the first two-dimensional electrophoresis map of vibrio cholerae, the aetiological agent of cholera disease. in this pathogen the efficient adaptation to detrimental conditions plays an important role in its survival in both the aquatic reservoir and human intestine. by proteome analysis we investigated the effect of mild acid treatment on the physiology of v. cholerae. more than 50 proteins were identified by matrix-assisted laser desorption/ionization-time of flight ...	2002	11987131
a molecular and phenotypic study of vibrio cholerae in iran.	vibrio cholerae is again the subject of attention on account of the current increase in the world-wide incidence of cholera. in this study, 200 clinical isolates of v. cholerae serotypes o1 and non-o1, non-o139, were collected from different provinces in iran. the isolates were subjected to biochemical analysis, antibiogram, pcr of toxin genes, plasmid profile, ribotyping and pulsed-field gel electrophoresis (pfge). the analysis of plasmid content showed that 33-96% of v. cholerae isolated from ...	2002	11990491
molecular epidemiology of 3 putative virulence genes for escherichia coli urinary tract infection-usp, iha, and iron(e. coli).	this study describes the epidemiological association of 3 putative genes for virulence of uropathogenic escherichia coli; uropathogenic specific protein (usp), a vibrio cholerae zot gene homologue; irga homologue adhesin (iha), a nonhemagglutinating adhesin; and iron(e. coli), a catechole siderophore receptor homologue. we compared the relative frequency in urinary tract infection (uti) isolates (n=508), compared with non-uti isolates (n=416). iron(e. coli) occurred 2.1-3.6 times more frequently ...	2002	11992291