Publications

diversity in the arrangement of the ctx prophages in classical strains of vibrio cholerae o1.	this study reports the results of a molecular analysis of the ctx prophages in classical biotype strains of vibrio cholerae o1 of clinical origin isolated between 1970 and 1979 in india. all strains were sensitive to group iv classical phage and polymyxin b but resistant to group 5 el tor phage. these phenotypic traits are consistent to that exhibited by the classical biotype. pcr studies reconfirmed their biotype assignment and showed the presence of intact ctx prophages and the presence of the ...	2000	10612727
inorganic polyphosphate is required for motility of bacterial pathogens.	the ppk gene encodes polyphosphate kinase (ppk), the principal enzyme in many bacteria responsible for the synthesis of inorganic polyphosphate (polyp) from atp. a null mutation in the ppk gene of six bacterial pathogens renders them greatly impaired in motility on semisolid agar plates; this defect can be corrected by the introduction of ppk gene in trans. in view of the fact that the motility of pathogens is essential to invade and establish systemic infections in host cells, this impairment i ...	2000	10613886
characterization of adhesive epitopes with the omps display system.	omps is an outer membrane protein of vibrio cholerae where it forms trimeric pores that function in the uptake of maltose and maltodextrins. based on sequence similarity to lamb proteins, a model of omps folding in the outer membrane has been constructed. according to this model, omps contains 18 transmembrane beta-strands and nine surface-accessible loops. adhesive epitopes can, when inserted into surface-accessible loop 4 (l4) and expressed in escherichia coli, retain their functional characte ...	2000	10601863
development of a deltaglna balanced lethal plasmid system for expression of heterologous antigens by attenuated vaccine vector strains of vibrio cholerae.	we have previously shown that more prominent immune responses are induced to antigens expressed from multicopy plasmids in live attenuated vaccine vector strains of vibrio cholerae than to antigens expressed from single-copy genes on the v. cholerae chromosome. here, we report the construction of a deltaglna derivative of v. cholerae vaccine strain peru2. this mutant strain, peru2deltaglna, is unable to grow on medium that does not contain glutamine; this growth deficiency is complemented by pke ...	2000	10603391
role of the neuroendocrine system in pathogenesis of gastroenteritis.	the concept of neuroendocrine modulation of infectious gastroenteritis adds another dimension to the pathophysiology of diarrhoeal diseases. furthermore it opens up new avenues for therapeutic intervention. until now, most interest has been directed at enterotoxin-producing bacteria, notably vibrio cholerae and the enterotoxigenic escherichia coli. however, more recently neuroendocrine recruitment has been implicated by other pathogens. the roles of vasoactive intestinal peptide, 5-hydroxytrypta ...	2000	11964824
cloning of the ctxb gene of vibrio cholerae and its expression in e.coli.	the ctxb gene encoding cholerae toxin subunit b was amplified from vibrio cholerae genomic dna by pcr. the result of sequencing indicated that ctxb gene encodes 124 amino acid residues. the sequence of ctxb gene was almost the same as that of reported except for the codon of thr 62. the expression plasmid pgex-ctxb was constructed by inserting ctxb gene into plasmid pgex-4t-2, containing gst gene, immediately downstream of the t7 promoter. the expressed plasmid was introduced into e.coli bl21(de ...	2000	12098792
severe cholera outbreak following floods in a northern district of west bengal.	an explosive epidemic of cholera in the district of malda in the state of west bengal, was induced by devastating floods resulting from overflowing of the two main rivers of the district, at the end of july 1998, affecting 15 blocks and 2 municipalities. diarrhoeal outbreak occurred around the middle of august after receding of the flood waters. within two weeks of its onset, the outbreak spread throughout the district. an investigation was conducted to understand the epidemiological characteris ...	2000	12452126
[pcr amplification and cloning of virulence expression regulatory gene toxr of vibrio cholerae].	in order to construct a genomic bivalent oral vaccine of leishmania donovani and vibrio cholerae, we amplified a 1.3 kb dna fragment from 7 strains of vibrio cholerae with primers p1 and p2. restriction endonuclease analysis of pcr amplified products from 9 strains of vibrio cholerae was performed by digestion with ecor i. the results revealed an ecor i site in the central part of toxr gene. the entire toxr gene of vibrio cholerae non-ct strain 7743 was amplified by pcr with primers p1 and p2, d ...	2000	12501605
cholera epidemic in and around loni a rural area in western maharashtra.		2000	12583433
serum antibody response induced in mice after oral administration of three different antigens of enterotoxigenic escherichia coli in enteric coated microparticles.	gastric digestion of these antigens plays an important role, decreasing the ability to deliver antigens to the gut-associated lymphoid tissue. to overcome this obstacle, microencapsulated antigens from enterotoxigenic escherichia coli (etec) were evaluated for oral immunization of mice.	2000	11179951
[cloning of the zot gene of vibrio cholerae and its expression in escherichia coli].	the zot gene encoding zonula occludens toxin was amplified from classic vibrio cholerae genomic dna by pcr. the result of sequencing indicated that zot gene encodes 399 amino acid residues. the sequence of zot gene was a little bit different from that of reported including 14 nucleotides and four amino acid residues. the expression plasmid pet-zot was constructed by inserting zot gene into plasmid pet-28a(+) containing the t7 promoter. the expression plasmid was induced into e. coli bl21 (de3) a ...	2000	11191759
seasonal, nontoxigenic vibrio cholerae o1 ogawa infections in the eastern region of saudi arabia.	surveillance for vibrio cholerae in the eastern region of saudi arabia has been ongoing since 1985 to detect and prevent local proliferation of imported cholera. in 1996 and 1997 the authors performed additional microbiologic and epidemiologic assessment of v. cholerae surveillance to better characterize a recurrent summertime pattern of v. cholerae infections in the eastern region of saudi arabia.	2000	11231182
modulation of intestinal permeability: a novel and innovative approach for the oral delivery of drugs, macromolecules and antigens.		2000	11255677
live bacterial delivery systems for development of mucosal vaccines.	by expression of foreign antigens in attenuated strains derived from bacterial pathogens and in non-pathogenic commensal bacteria, recombinant vaccines are being developed that aim to stimulate mucosal immunity. recent advances in the pathogenesis and molecular biology of these bacteria have allowed rational development of new and improved bacterial carriers and more effective gene expression systems. these advances have improved the performance and versatility of these delivery systems to induc ...	2000	11249657
improvements for multipurpose bacteriological identification tables to suit the diagnosis of vibrio cholerae.	the aim of the study was to reduce to key tests the 4 extensive polyvalent diagnostic biochemical tables most widely used in croatia and to adapt them for the demonstration of vibrio cholerae and its differentiation from the 3 vibrios (v. alvinolyticus, v. mentschikovii, v. fluvialis) important in differential diagnosis. the fourth table has now been adapted to differentiate among all 12 vibrio species known to be human pathogens (v. mimicus, v. cincinatiensis, v. holisae, v. damsela, v. furnisi ...	2000	11268787
reappearance of vibrio cholerae serogroup 0139 in yavatmal during june-august-1998.		2000	11271727
clinical profile of non-o1 strain-o139 of vibrio cholerae in the region of ambajogai, maharashtra.	to study clinical profile of the newly emerged novel strain non-o1, o139 of vibrio cholerae, in the region of ambajogai, district beed of maharashtra.	2000	11273144
evaluation of synthetic schemes to prepare immunogenic conjugates of vibrio cholerae o139 capsular polysaccharide with chicken serum albumin.	vibrio cholerae serotype o139 is a new etiologic agent of epidemic cholera. there is no vaccine available against cholera caused by this serotype. v. cholerae o139 is an encapsulated bacterium, and its polysaccharide capsule is an essential virulent factor and likely protective antigen. this study evaluated several synthetic schemes for preparation of conjugates of v. cholerae o139 capsular polysaccharide (cps) with chicken serum albumin as the carrier protein (csa) using 1-ethyl-3(3-dimethylami ...	2000	11294508
year's comments for 2000.		2000	11334302
protection from cholera by adding lime juice to food - results from community and laboratory studies in guinea-bissau, west africa.	epidemiological studies have shown that food plays an important role in the transmission of vibrio cholerae, and different foods have been incriminated in many epidemic outbreaks of cholera. storing contaminated meals at ambient temperatures allows growth of v. cholerae. some ingredients such as lime juice may inhibit the survival of v. cholerae in foods. during an epidemic caused by v. cholerae o1 in guinea-bissau in 1996, a case control study was conducted in the capital bissau, the main affec ...	2000	10929141
passive protection of serum from volunteers inoculated with attenuated strain 638 of vibrio cholerae o1 in animal models.	as part of the studies to obtain an oral vaccine against cholera disease, the protective effect of serum from volunteers inoculated in a controlled trial with a candidate live attenuated vaccine of vibrio cholerae o1, el tor ogawa (638; ctxφ mutant, hap::cela), was tested. it was confirmed that the serum, as well as the purified igg and iga from the volunteers had a protective effect in both of the animal models used, although the purified antibodies needed the presence of complement to be p ...	2000	10930693
cloning and functional studies of a luxo regulator luxt from vibrio harveyi.	luxo is the central regulator integrating the quorum sensing signals controlling autoinduction of luminescence in vibrio harveyi. we have previously purified to homogeneity a new lux regulator, luxt, that binds to the luxo promoter. based on the sequence of the tryptic peptides of luxt, degenerate oligonucleotides were designed for pcr of the genomic dna. a 273 bp pcr dna fragment containing sequences encoding the tryptic peptides was extended by inverse pcr to obtain the complete gene (luxt) en ...	2000	11121579
molecular epidemiological study of vibrio cholerae isolates from infected patients in teheran, iran.	a total of 110 clinical isolates of vibrio cholerae o1 biotype el tor serotype ogawa isolated in a recent outbreak from different districts of teheran, iran, was subjected to 99 carbon source utilisation tests, ribotyping and toxinogenotyping. pcr showed that the genes encoding cholera toxin (ctxa), toxin co-regulated pilus (tcp), accessory cholera enterotoxin (ace) and zonula occludens toxin (zot) were present in 100%, 100%, 97.3% and 99.1% of the isolates, respectively. restriction fragment le ...	2000	11129720
current status of cholera and rise of novel mucosal vaccine.	three serious cholera epidemics have threatened the world during the last 10 years. as a countermeasure against such cholera epidemics, three vaccines, cvd 103-hgr, wc/rbs, and vietnamese wc, showed good performance. cvd 103-hgr is a recombinant attenuated live vaccine for travelers, and its highly safety and protective efficacy have been demonstrated in volunteers in advanced countries. wc/rbs, which consists of heat- and formalin-killed bacteria and cholera toxin b subunit, protects the vaccin ...	2000	11135702
clinical manifestations and characterization of extra-intestinal vibrio cholerae non-o1, non-o139 infections in denmark.		2000	11168070
cholera in its present day scenario.	cholera existed in many parts of the world since olden days. gangetic delta is considered as the home of the disease. since 1970 there has been a significant development of the disease with its ecologic and epidemiologic aspects. vibrio cholerae non-01 strain in taxonomically separated from v cholerae 01 strain. though 01 strain causes epidemic outbreaks, still non-01 has been implicated to cause cholera like illness. while humans are long considered to be the only reservoir of v cholerae 01 str ...	2000	11143856
outbreak of cholera caused by vibrio cholerae 01 intermediately resistant to norfloxacin at malda, west bengal.	during the end of september 1997, an unusual outbreak of severe dehydrating watery diarrhoea cases and deaths were reported from malda town. vibrio cholerae 01 el tor, the causative agent responsible for this episode was isolated from 56.5% of cases sampled. three of the five drinking water samples were also positive for v cholerae 01. majority of cases were adults. isolated strains were uniformly resistant to furazolidone and intermediately to norfloxacin. indiscriminate use of antibiotic shoul ...	2000	11143861
spectrum of gut immunologic reactions: selective induction of distinct responses to vibrio cholerae wo7 and its toxin.	past studies with vibrio cholerae have shown that cholera toxin (ct) is mainly responsible for inducing t helper type 2 (th2) responses with systemic igg1, ige and mucosal secretory iga (siga) antibodies. in this study, v. cholerae wo7, which produces novel toxin unrelated to ct, was given orally to mice in order to determine whether the strain v. cholerae wo7 differs from v. cholerae 569b, which produces ct, in the nature of responses generated at the gut and splenic level. the analysis of immu ...	2000	11145274
the complete genome sequence of vibrio cholerae: a tale of two chromosomes and of two lifestyles.	vibrio cholerae o1 has figured prominently in the history of infectious diseases as a cause of periodic global epidemics, an affliction of refugees in areas of social strife and as the disease first subjected to modern epidemiological analysis during the classic investigations of john snow in mid-19th century london [1]. thus, publication of the entire genome sequence of v. cholerae o1 (biotype el tor) in nature [2] by a consortium of investigators from the institute for genomic research, the un ...	2000	11178241
evidence for symmetric chromosomal inversions around the replication origin in bacteria.	whole-genome comparisons can provide great insight into many aspects of biology. until recently, however, comparisons were mainly possible only between distantly related species. complete genome sequences are now becoming available from multiple sets of closely related strains or species.	2000	11178265
regulation of intercellular tight junctions by zonula occludens toxin and its eukaryotic analogue zonulin.	the intestinal epithelium represents the largest interface between the external environment and the internal host milieu and constitutes the major barrier through which molecules can either be absorbed or secreted. there is now substantial evidence that tight junctions (tj) play a major role in regulating epithelial permeability by influencing paracellular flow of fluid and solutes. tj are one of the hallmarks of absorptive and secretory epithelia. evidence now exists that tj are dynamic rather ...	2000	11193578
distinct effects of vibrio cholerae haemagglutinin/protease on the structure and localization of the tight junction-associated proteins occludin and zo-1.	vibrio cholerae produces a little-studied cytotoxin, haemagglutinin/protease (ha/p), in addition to several better-characterized enterotoxins, i.e. cholera toxin (ct), zonula occludens toxin (zot) and accessory cholera enterotoxin (ace). we have found recently that ha/p perturbs the barrier function of mardin-darby canine kidney epithelial cell line i (mdck-i) by affecting the intercellular tight junctions (tjs) and the f-actin cytoskeleton. in the present study we have assessed more specificall ...	2000	11207559
cross-talk between enteric pathogens and the intestine.	enteric pathogens finely regulate the expression of virulence genes in reply to stimuli generated by the intestinal environment. this minireview focuses on recently discovered strategies developed by enteric bacteria to cause intestinal secretion through the elaboration of factors that share structure and function with specific host counterparts. such bacterial antigens appear to interfere largely with the epithelial cell signalling that physiologically regulates the numerous and, as yet not ful ...	2000	11207565
[vibrio cholerae o139 bacteriophages].	cholera bacteriophages have been isolated from 27 lysogenic cultures of v. cholerae o139. as shown the pages under study belong to two morphological groups a1 and f1 and serological types ii and xii. the use of prophage typing and the sensitivity test to specific phage made it possible to differentiate v. cholerae strains, serogroup o139.	2000	11210629
[synthesis of protective antigens during submerged cultivation of vibrio cholerae].	the effectiveness of dot immunoanalysis for evaluating the dynamics of the synthesis of o-antigen, cholera toxin, neuraminidase, adhesin cfa1 in the process of the reactor cultivation of v. cholerae used for the production of oral chemical cholera vaccine is shown. the established regularities of the synthesis of the protective antigens of v. cholerae in the process of scaled-up cultivation are discussed.	2000	11210646
[bactericidal properties of hemo-cytolysin from vibrio cholerae non o1 p-11702 strain in a panel of indicator cultures for detection of vibriocins].	the influence of the preparation of hemo-cytolysin, obtained from v. cholerae non o1 strain p-11702 and inducing lysis of both red blood cells and v. cholerae cultures using a panel of indicator cultures for the detection of vibriocins, was studied. the set of indicator cultures contained 2 shigella flexneri strains, 1 s. dysenteriae strain, 3 s. sonnei strains, 3 escherichia coli strains and 2 v. cholerae strains, one of them being atypical. hemo-cytolysin exhibited lytic activity with respect ...	2000	11210647
[factors contributing to preservation of vibrio cholerae in water reservoirs].	the summarized data of literature concerning the survival of v. cholerae in the environment and the influence of abiotic and biotic factors on this process are presented. these data make it possible to regard cholera as sapronosis and to form an idea of the role of factors contributing to the survival of v. cholerae in the environment and to its spread among human population.	2000	11210656
new insights on the emergence of cholera in latin america during 1991: the peruvian experience.	after a century of absence, in late january 1991, vibrio cholerae invaded the western hemisphere by way of peru. although a number of theories have been proposed, it is still not understood how that invasion took place. we reviewed the clinical records of persons attending hospital emergency departments in the major coastal cities of peru from september through january of 1989/1990 and 1990/1991. we identified seven adults suffering from severe, watery diarrhea compatible with a clinical diagnos ...	2000	11220769
[the use if francisella tularensis lipopolysaccharide in the dot solid phase enzyme immunoassay].	to determine antitularemia antibodies in the sera of humans and animale, the possibility of using dot immunoassay with the use of f. tularensis lipopolysaccharide (lps) as antigen-containing preparation was ascertained. experiments demonstrated that this method made it possible to determine specific antitularemia antibodies in the sera of sick and immunized humans and animals. investigetions carried out with the use of heterologous antisera to f. novicida, f. novicida-like and f. philomiragia, a ...	2000	11220974
[bactericidal properties of the vibrio cholerae non o1 bacteriolysin].	the influence of the preparation of hemocytolysin, obtained from v. cholerae non o1 (strain p-11702), on the growth of v. cholerae cells was studied. the study revealed that hemocytolysin is capable of inducing partial or complete bacterial lysis on the place of its application, depending on the protein load of the substance and the inoculation dose of microbes. two electrophoretic fractions with molecular weights of 14 and 14.5 kd induced the cytolysis of sheep, rabbit, guinea-pig red blood cel ...	2000	11220977
[genetic markers of epidemic strains of vibrio cholerae].	in this review new data on the key pathogenicity genes of v. cholerae are presented. as shown on the basis of the analysis of the latest information on the structure of the genomes of different v. cholerae strains, structural genes ctxab coding cholera toxin may not serve as the only marker of epidemically dangerous strains. more complete and reliable information for the evaluation of the epidemic potential of v. cholerae isolated from the environment may be obtained by the simultaneous detectio ...	2000	11220978
requirements for conversion of the na(+)-driven flagellar motor of vibrio cholerae to the h(+)-driven motor of escherichia coli.	bacterial flagella are powered by a motor that converts a transmembrane electrochemical potential of either h(+) or na(+) into mechanical work. in escherichia coli, the mota and motb proteins form the stator and function in proton translocation, whereas the flig protein is located on the rotor and is involved in flagellar assembly and torque generation. the sodium-driven polar flagella of vibrio species contain homologs of mota and motb, called poma and pomb, and also contain two other membrane ...	2000	10894732
vibrio cholerae h-ns silences virulence gene expression at multiple steps in the toxr regulatory cascade.	h-ns is an abundant nucleoid-associated protein involved in the maintenance of chromosomal architecture in bacteria. h-ns also has a role in silencing the expression of a variety of environmentally regulated genes during growth under nonpermissive conditions. in this study we demonstrate a role for h-ns in the negative modulation of expression of several genes within the toxr virulence regulon of vibrio cholerae. deletion of hns resulted in high, nearly constitutive levels of expression of the g ...	2000	10894740
sunlight-induced propagation of the lysogenic phage encoding cholera toxin.	in toxigenic vibrio cholerae, the cholera enterotoxin (ct) is encoded by ctxphi, a lysogenic bacteriophage. the propagation of this filamentous phage can result in the origination of new toxigenic strains. to understand the nature of possible environmental factors associated with the propagation of ctxphi, we examined the effects of temperature, ph, salinity, and exposure to direct sunlight on the induction of the ctx prophage and studied the transmission of the phage to potential recipient stra ...	2000	10899892
transcriptional regulation of transport and utilization systems for hexuronides, hexuronates and hexonates in gamma purple bacteria.	the comparative approach is a powerful tool for the analysis of gene regulation in bacterial genomes. it can be applied to the analysis of regulons that have been studied experimentally as well as that of regulons for which no known regulatory sites are available. it is assumed that the set of co-regulated genes and the regulatory signal itself are conserved in related genomes. here, we use genomic comparisons to study the regulation of transport and utilization systems for sugar acids in gamma ...	2000	11115104
change in receptor-binding specificity of recent human influenza a viruses (h3n2): a single amino acid change in hemagglutinin altered its recognition of sialyloligosaccharides.	human h3n2 influenza a viruses were known to preferentially bind to sialic acid (sa) in alpha2,6gal linkage on red blood cells (rbc). however, h3n2 viruses isolated in mdck cells after 1992 did not agglutinate chicken rbc (crbc). experiments with point-mutated hemagglutinin (ha) of a/aichi/51/92, one of these viruses, revealed that an amino acid change from glu to asp at position 190 (e190d) was responsible for the loss of ability to bind to crbc. a/aichi/51/92 did not agglutinate crbc treated w ...	2000	11118381
vibrio cholerae cytolysin: assembly and membrane insertion of the oligomeric pore are tightly linked and are not detectably restricted by membrane fluidity.	hemolytic strains of vibrio cholerae secrete a cytolysin that, upon binding as a monomer, forms pentameric pores in animal cell membranes. pore formation is inhibited at low temperature and in the absence of cholesterol. we here posed the following questions: firstly, can oligomerization be observed in the absence of pore formation? secondly, is membrane fluidity responsible for the effect of temperature or of cholesterol upon pore formation? the first issue was approached by chemical cross-link ...	2000	11118538
featured organism: pathogen special: vibrio cholerae, pseudomonas aeruginosa and xylella fastidiosa.	one could almost say that it is the latest fashion to sequence a bacterial genome. however, this would belittle the efforts of those working on these important organisms, whose data will greatly help those working on the prevention of disease in the fields of medicine and agriculture. in this feature we present a guided tour of the latest additions to the 'sequenced microbes' club. vibrio cholerae is the causative agent of cholera, which is still a threat in countries with poor sanitation and un ...	2000	11119308
[bacteriological particularities of vibrio cholerae serotype ogawa, biotype el tor isolated in burundi].		2000	11100450
pathogenicity islands and phage conversion: evolutionary aspects of bacterial pathogenesis.	horizontal gene transfer plays a key role in the generation of novel bacterial pathogens. besides plasmids and bacteriophages, large genomic regions termed pathogenicity islands (pais) can be transferred horizontally. all three mechanisms for dna exchange or transfer may be important for the evolution of bacterial pathogens.	2000	11100826
novel targets for the pharmacotherapy of diarrhoea: a view for the millennium.	acute diarrhoea continues to carry a high morbidity and mortality worldwide. intestinal infection is the major cause of acute diarrhoea although the prevalence of individual pathogens varies according to geographic location. in many countries in the industrialized world, reports of intestinal infections continue to increase; these are largely related to waterborne and foodborne outbreaks. acute diarrhoea may be due to increased intestinal secretion, commonly as a result of infection with enterot ...	2000	11100992
molecular properties of bacterial multidrug transporters.	one of the mechanisms that bacteria utilize to evade the toxic effects of antibiotics is the active extrusion of structurally unrelated drugs from the cell. both intrinsic and acquired multidrug transporters play an important role in antibiotic resistance of several pathogens, including neisseria gonorrhoeae, mycobacterium tuberculosis, staphylococcus aureus, streptococcus pneumoniae, pseudomonas aeruginosa, and vibrio cholerae. detailed knowledge of the molecular basis of drug recognition and t ...	2000	11104814
[evaluation of cytotoxic activity of vibrio cholerae non-01 culture filtrate on established cell lines and human diploid cells].	the cell-destroying effect of cell free filtrates of 90 v. cholerae non-01 cultures was measured by titration method in 3 established cell lines: cho, hela and vero and in 3 human diploid cells cultures: mrc-5, wi-38 and pz. the vibrio strains differed in the titre of toxic effect. most sensitive was cho cell line, least sensitive were human diploid cell cultures. it was found that bacterial strains produced different substances toxic for various cell lines. among them nag-st toxin produced by 4 ...	2000	11107788
[toxigenic vibrio cholerae non-01].	the antimicrobial susceptibility and the presence of a heat-stable toxin were researched into 100 non-01 vibrio cholerae strains sent by 7 different health centers to the national reference laboratory of acute diarrheal diseases in "pedro kourí" tropical medicine institute. the presence of 20% toxigenic non-01 vibrio cholerae was detected, a figure substantially higher than that reported in other geographic areas, except for endemic areas. this result will make it possible to set epidemiological ...	2000	11107903
use of the omps-display--system to localize the receptor-binding region in the papg adhesin of uropathogenic escherichia coli.		2000	11109098
characterization of the multimeric eps complex required for cholera toxin secretion.	vibrio cholerae causes diarrheal disease through colonization of the small intestine. a critical aspect of v. cholerae pathogenesis is its ability to actively secrete cholera toxin to the extracellular environment. this occurs via the type ii secretion pathway, where the toxin subunits are first transported to the periplasm through the sec pathway. following folding and assembly the toxin is then translocated across the outer membrane by a specialized extracellular protein secretion (eps) machin ...	2000	11111909
vibriobactin biosynthesis in vibrio cholerae: vibh is an amide synthase homologous to nonribosomal peptide synthetase condensation domains.	the vibrio cholerae siderophore vibriobactin is biosynthesized from three molecules of 2,3-dihydroxybenzoate (dhb), two molecules of l-threonine, and one of norspermidine. of the four genes positively implicated in vibriobactin biosynthesis, we have here expressed, purified, and assayed the products of three: vibe, vibb, and vibh. all three are homologous to nonribosomal peptide synthetase (nrps) domains: vibe is a 2,3-dihydroxybenzoate-adenosyl monophosphate ligase, vibb is a bifunctional isoch ...	2000	11112537
reconstitution and characterization of the vibrio cholerae vibriobactin synthetase from vibb, vibe, vibf, and vibh.	vibriobactin [n(1)-(2,3-dihydroxybenzoyl)-n(5),n(9)-bis[2-(2, 3-dihydroxyphenyl)-5-methyloxazolinyl-4-carboxamido]norspermidine] , is an iron chelator from the cholera-causing bacterium vibrio cholerae. the six-domain, 270 kda nonribosomal peptide synthetase (nrps) vibf, a component of vibriobactin synthetase, has been heterologously expressed in escherichia coli and purified. vibf has an unusual nrps domain organization: cyclization-cyclization-adenylation-condensation-peptidyl carrier protein- ...	2000	11112538
chemoenzymatic synthesis of sialyl oligosaccharides with sialidases employing transglycosylation methodology.	a series of sialyloligosaccharides was synthesized using the transglycolytic activity of the sialidases from vibrio cholerae, clostridium perfringens, salmonella typhimurium, and newcastle disease virus. according to their hydrolytic activities the sialidases from v. cholerae and c. perfringens catalyze preferentially the formation of sialyl alpha(2-6)-linkages whereas the sialidases from s.typhimurium and newcastle disease virus show a distinct preference for alpha(2-3) directed sialylations. u ...	2000	11112571
analysis of hi0220 protein from haemophilus influenzae, a novel structural and functional analog of arcb protein from escherichia coli.	a haemophilus influenzae gene encoding a protein with high homology to arcb receptor protein from escherichia coli has been cloned. an error in the previously reported sequence of this gene has been found, thus increasing its open reading frame. the cloned gene comprising the entire open reading frame restores oxygen-dependent regulation of succinate dehydrogenase in an arcb-deficient e. coli strain. thus, this gene is a functional analog of arcb from e. coli. by screening partially sequenced ba ...	2000	11112851
unexpected effects of pathogens on epithelial na+ channels.		2000	10981518
comparison of global transcription responses allows identification of vibrio cholerae genes differentially expressed following infection.	comparison of global transcription profiles of vibrio cholerae grown in vitro and in vivo revealed that 20% of the genome was repressed and about 5% was induced under in vivo conditions. hybridization with the cloned genes revealed that the virulence genes ctx, toxr, toxt and tcpa were induced under in vivo conditions. dissection of two in vivo induced cosmids identified another set of three genes homologous to che y1 involved in motility and chemotaxis, pnuc encoding the major component of the ...	2000	10981695
expanding multiple antibiotic resistance among clinical strains of vibrio cholerae isolated from 1992-7 in calcutta, india.	antimicrobial susceptibilities of vibrio cholerae strains isolated from cholera patients admitted to the infectious diseases hospital, calcutta, india for 6 years were analysed to determine the changing trends; 840 v. cholerae strains isolated in 1992-1997 were included in this study. among v. cholerae serogoup o1 and o139, ampicillin resistance increased from 1992 (35 and 70%, respectively) to 1997 (both serogroups 100%). resistance to furazolidone and streptomycin was constantly high among v. ...	2000	10982062
web-based visualization tools for bacterial genome alignments.	with the increase in the flow of sequence data, both in contigs and whole genomes, visual aids for comparison and analysis studies are becoming imperative. we describe three web-based tools for visualizing alignments of bacterial genomes. the first, called enteric, produces a graphical, hypertext view of pairwise alignments between a reference genome and sequences from each of several related organisms, covering 20 kb around a user-specified position. insertions, deletions and rearrangements rel ...	2000	10982867
regulation of vibrio cholerae genes required for acid tolerance by a member of the "toxr-like" family of transcriptional regulators.	the ability of the intestinal pathogen vibrio cholerae to undergo an adaptive stress response, known as the acid tolerance response (atr), was previously shown to enhance virulence. an essential component of the atr is cada-mediated lysine decarboxylation. cada is encoded by the acid- and infection-induced gene cada. herein, cada is shown to be the second gene in an operon with cadb, encoding a lysine/cadaverine antiporter. cadc, which is 5' of cadb, encodes an acid-responsive, positive transcri ...	2000	10986235
molecular analyses of a putative ctxphi precursor and evidence for independent acquisition of distinct ctx(phi)s by toxigenic vibrio cholerae.	the genes encoding cholera toxin (ctxa and ctxb) are encoded in the genome of ctxphi, a filamentous phage that infects vibrio cholerae. to study the evolutionary history of ctxphi, we examined genome diversity in ctx(phi)s derived from a variety of epidemic and nonepidemic vibrio sp. natural isolates. among these were three v. cholerae strains that contained ctx prophage sequences but not the ctxa and ctxb genes. these prophages each gave rise to a plasmid form whose genomic organization was ver ...	2000	10986258
cholera vaccines.	cholera causes significant morbidity and mortality worldwide. for travelers, the risk of developing cholera per month of stay in a developing country is approximately 0.001%-0.01%, and cholera may present as traveler's diarrhea. in the united states, only a poorly tolerated, marginally effective, parenterally administered, phenol-inactivated vaccine is available. outside the united states, 2 additional vaccines are commercially available: an oral killed whole cell-cholera toxin recombinant b sub ...	2000	10987721
genomics happens.	cholera has been the scourge of humankind for centuries. although most of the time vibrio cholerae, the microbe that causes this disease, is a free-living organism inhabiting aquatic environments, it can invade human hosts causing severe diarrhea and often death. as dirita explains in his perspective, sequencing of the entire v. cholerae genome is revealing new facets of the pathogenesis of this dangerous microbe.	2000	10991736
purification and characterization of a cytotonic protein expressed in vitro by the live cholera vaccine candidate cvd 103-hgr.	cholera vaccines developed by the deletion of ctx genes from vibrio cholerae induce a residual reactogenicity in up to 10% of vaccinees. a novel cytotonic agent named secreted cho cell elongating protein (s-cep) was purified from culture supernatants of cvd 103-hgr (levine et al., lancet ii:467-470, 1988). five fractionation steps yielded electrophoretically pure s-cep with an m(r) of 79,000. a partially purified preparation caused fluid accumulation in the sealed infant mouse model. the amino t ...	2000	10992523
enterotoxin-specific immunoglobulin e responses in humans after infection or vaccination with diarrhea-causing enteropathogens.	cholera toxin (ct)-specific antibody responses of the immunoglobulin e (ige) isotype in the sera of adult patients suffering from infection with either vibrio cholerae o1, v. cholerae o139, or enterotoxigenic escherichia coli (etec) were analyzed and compared with those in the sera of volunteers immunized with a bivalent b subunit o1/o139 whole-cell cholera vaccine. a significant ige response to ct was observed in 90% of the patients with v. cholerae o1 infection (18 of 20; p = <0.001) and 95% o ...	2000	10992527
cholera toxin and related enterotoxins: a cell biological and immunological perspective.	cholera toxin (ctx) from vibrio cholerae and the closely related escherichia coli heat-labile enterotoxin (etx) are the primary virulence factors responsible for causing cholera and traveller's diarrhea, respectively. studies on the mode of action of these toxins on gut epithelial cells have revealed important insights into the mechanisms of toxin uptake and trafficking in eukaryotic cells. however, of perhaps even greater fascination have been the discoveries that ctx and etx exhibit remarkable ...	2000	10994530
translocases: a bacterial tunnel for drugs and proteins.	unrelated translocases extrude proteins or antimicrobial agents across both membranes of the cell envelope in gram-negative bacteria. the tolc protein links the translocases to the external environment. the recently determined crystal structure of tolc shows how this universal tunnel operates.	2000	10996810
a new bacterial white spot syndrome (bwss) in cultured tiger shrimp penaeus monodon and its comparison with white spot syndrome (wss) caused by virus.	this paper describes a new bacterial white spot syndrome (bwss) in cultured tiger shrimp penaeus monodon. the affected shrimp showed white spots similar to those caused by white spot syndrome virus (wssv), but the shrimp remained active and grew normally without significant mortalities. the study revealed no evidence of wssv infection using electron microscopy, histopathology and nested polymerase chain reaction. electron microscopy indicated bacteria associated with white spot formation, and wi ...	2000	10907134
terminal glycosylation of bovine uroplakin iii, one of the major integral-membrane glycoproteins of mammalian bladder.	uroplakin iii (upiii) is one of the major transmembrane glycoproteins exposed at the luminal face of mammalian bladder. we investigated the terminal glycosylation of bovine upiii in order to ascertain whether it contains the alpha 2,3-sialylated sequence thus potentially serving as a receptor for uropathogenic escherichia coli expressing type s adhesins. we report the occurrence of sialic acid in alpha 2,3- and alpha 2,6-linkage to galactose in bovine upiii glycans as evidenced by the sensitivit ...	2000	10913821
iem101, a naturally attenuated vibrio cholerae strain as carrier for genetically detoxified derivatives of cholera toxin.	two mutants of cholera toxin (cts106 containing a pro106-->ser substitution and ctk63 containing a ser63-->lys substitution) with greatly reduced or no toxicity respectively, were expressed in the naturally attenuated iem101 vibrio cholerae strain (el tor, ogawa) which does not express cholera toxin (ct). expression was driven by the natural promoter of ct, or by a promoter known to induce strong in vivo expression such as nirb. in the rabbit ileal loop assay, where 10(4) wild type bacteria were ...	2000	10924789
[vibrio cholerae o139 isolated from humans and the water from open reservoirs: a comparative genotyping].	the comparative study of the genomes of v. cholerae o139 isolated from humans and from water of surface reservoirs was carried out with the use of single- and double-primer polymerase chain reaction (pcr). the profiles of polymorphic dna fragments obtained in this study made it possible to find out differences between groups of strains, as well as the individual features of some of them. the comparison of strains isolated from humans and from water in single-primer pcr revealed that they, in spi ...	2000	10925861
[the expression of the pathogenic properties of the vibrio cholerae o139 serogroup in vitro].	cholera toxin, hemolysin, dermonecrotic and proteolytic factors have been detected and identified in v. cholerae o139. the production of these substances has been found to depend on the conditions of the cultivation of vibrios, and the types of proteases have been determined.	2000	10925862
[the apud-system function of the intestines and the morphological changes in the internal organs of adult rabbits infected with toxigenic vibrio cholerae].	v. cholerae infection with clearly pronounced diarrhea was reproduced in adult rabbits with the use of the ritard system. the state of the apud system of the intestine of the animals and morphological changes in internal organs in experimental cholera were described. as noted in this study, the manifestation of changes in the intestine and other organs, as well as the reaction of apudocytes to v. cholerae infection, were linked with the intensity of diarrhea and the time of the death of the anim ...	2000	10925863
[strains of vibrio cholerae serogroups o1 and o139 that produce the basic protective antigens].	to find out stable and effective producers of major protective antigens intended for use as components of cholera chemical vaccine against v. cholerae strains of serogroups o and o139, the comparative analysis of the production of cholera toxin, toxin-coregulated pili (tcp), antigens o1 and o139, polysaccharide capsule and outer membrane protein ompu in different v. cholerae strains groups o1 and o139 has been made. v. cholerae strain km68, serogroup o1, has been found capable of the production ...	2000	10925874
prediction of transcription terminators in bacterial genomes.	this study describes an algorithm that finds rho-independent transcription terminators in bacterial genomes and evaluates the accuracy of its predictions. the algorithm identifies terminators by searching for a common mrna motif: a hairpin structure followed by a short uracil-rich region. for each terminator, an energy-scoring function that reflects hairpin stability, and a tail-scoring function based on the number of u nucleotides and their proximity to the stem, are computed. a confidence valu ...	2000	10926490
role and behaviour of the hydrophobic conditions in bacterial adhesion to incurrent siphon in a bivalve mollusc.	surface hydrophobicity is a widely distributed characteristic among human bacterial pathogens playing an important role in microbes retention by the incurrent siphon of a marine bivalve. feeding retention experiments with the bivalve mesodesma donacium was done with hydrophobic strains alone (staphylococcus aureus, salmonella paratyphi, vibrio cholerae) or with mixed cultures using a hydrophilic strain (aeromonas hydrophila). results showed that hydrophobic bacteria are retained in greater numbe ...	2000	10997493
delivery of protein antigens and dna by virulence-attenuated strains of salmonella typhimurium and listeria monocytogenes.	two different plasmid-vector systems were developed which allow the efficient production and presentation of protein antigens in antigen-presenting cells (apc) by means of virulence-attenuated bacteria. the first antigen-delivery system is based on the secretion machinery of the escherichia coli hemolysin (hlya-type i secretion system), which transports proteins, possessing the specific hlya secretion signal (hlya(s)) at the c-terminus, across both membranes of gram-negative bacteria. this syste ...	2000	11000455
activation, stimulation and uptake of bacterial ghosts in antigen presenting cells.	bacterial ghosts have been shown to be an innovative system to prepare vaccines of various bacteria with all features of the intact bacterial cell envelopes, especially all antigenic epitopes, but also to target recombinant proteins inserted in the cell envelopes of the ghost preparations to specific antigen presenting cells. to investigate the activation of the antigen presenting cell by bacterial ghosts in more detail we studied the uptake of bacterial ghosts in dendritic porcine cells and raw ...	2000	11000461
characterization and immunogenicity of vibrio cholerae ghosts expressing toxin-coregulated pili.	bacterial ghosts are attractive for use as non-living vaccines and as carriers of heterologous antigens of vaccine relevance. ghosts were prepared from vibrio cholerae strains of o1 or o139 serogroup after growth under culture conditions, which favor or repress the production of toxin-coregulated pili (tcp). immunoblotting confirmed the tcp status of these v. cholerae ghosts (vcg), which retained the cellular morphology and envelope sub-component profile of viable bacteria. rabbits were immunize ...	2000	11000467
detection of faecal leucocytes & erythrocytes from stools of cholera patients suggesting an evidence of an inflammatory response in cholera.	detection of faecal leucocytes and rbcs in stool samples of cholera patients has been reported in a small number of studies. this study extends these observations by examining stool samples of cholera patients in calcutta.	2000	11006654
vibrio cholerae o139 bengal: a descriptive study.	a prospective study was conducted to determine the clinical and laboratory characteristics and the clinical course of cholera due to vibrio cholerae o139 bengal. the study subjects included 22 adult males with stool culture-proven v. cholerae o139. on enrollment, mean +/- sd concentrations (mmol/l) of serum sodium, potassium, chloride, and bicarbonate were 134 +/- 3, 4 +/- 1, 102 +/- 4, and 13 +/- 4 respectively, and stool sodium, potassium, chloride, and bicarbonate concentrations were 120 +/- ...	2000	11014767
production of heat-labile enterotoxin by strains of aeromonas veronii bv veronii.	three isolates of aeromonas veronii bv veronii (2 environmental, one blood infection) were examined to see if they produce any enterotoxin and, if so, to determine its characteristics. two isolates caused fluid accumulation in the initial rabbit ileal loop tests. the other strain did so after a single passage through the rabbit ileal loop. all the isolates showed gradual enhancement of fluid secretion after each subsequent passage. inocula of 1 x 10(4) viable cells and 0.25 ml of culture filtrat ...	2000	11014770
class 1 integron-borne, multiple-antibiotic resistance encoded by a 150-kilobase conjugative plasmid in epidemic vibrio cholerae o1 strains isolated in guinea-bissau.	in the 1996-1997 cholera epidemic in guinea-bissau, surveillance for antimicrobial resistance showed the emergence of a multidrug-resistant strain of vibrio cholerae o1 during the course of the epidemic. the strain was resistant to ampicillin, erythromycin, tetracycline, furazolidone, aminoglycosides, trimethoprim, and sulfamethoxazole. concomitant with the emergence of this strain, we observed a resurgence in the number of registered cholera cases as well as an increase in the case fatality rat ...	2000	11015401
bacterial virulence gene regulation: an evolutionary perspective.	coevolution between bacteria and their plant or animal hosts determines characteristics of the interaction, the bacterial virulence genes involved, and the regulatory systems controlling expression of virulence genes. the long-standing association between salmonellae and their animal hosts has resulted in the acquisition by salmonella subspecies of a variety of virulence genes and the evolution of complex regulatory networks. the particular repertoire of virulence genes acquired by different sal ...	2000	11018137
detection of toxigenic vibrio cholerae from environmental water samples by an enrichment broth cultivation-pit-stop semi-nested pcr procedure.	a pit-stop semi-nested pcr assay for the detection of toxigenic vibrio cholerae in environmental water samples was developed and its performance evaluated. the pcr technique amplifies sequences within the cholera toxin operon specific for toxigenic v. cholerae. the pcr procedure coupled with an enrichment culture detected as few as four v. cholerae organisms in pure culture. treated sewage, surface, ground and drinking water samples were seeded with v. cholerae and following enrichment, a detect ...	2000	11021588
the vibrio cholerae o1 chromosomal integron.	until the discovery of the vibrio cholerae repeat (vcr), the gene capture and expression systems termed integrons had been typically associated with antibiotic-resistance gene cassettes with usually less than five genes in an array. a method is described for the cloning of the ends of large cassette arrays. conserved restriction sites within vcrs facilitated the mapping by southern hybridization and cloning of the 5' end of the vcr array, and using appropriate fragments it was possible to develo ...	2000	11021935
genetic relationships between clinical and environmental vibrio cholerae isolates based on multilocus enzyme electrophoresis.	a total of 107 isolates of vibrio cholerae, including 29 strains belonging to serogroup o139, were studied using multilocus enzyme electrophoresis (mlee) to determine allelic variation in 15 housekeeping enzyme loci. all loci were polymorphic and 99 electrophoretic types (ets) were identified from the total sample. no significant clustering of isolates was detected in the dendrogram generated from a matrix of coefficients of distances with respect to serogroup, biotype or country of isolation. t ...	2000	11021936
antisense pna effects in escherichia coli are limited by the outer-membrane lps layer.	antisense peptide nucleic acids (pnas) can inhibit escherichia coli gene expression and cell growth through sequence-specific rna binding, and this opens possibilities for novel anti-infective agents and tools for microbial functional genomics. however, the cellular effects of pnas are limited relative to effects in cell extracts, presumably because of cell barrier components such as the outer-membrane lipopolysaccharide (lps) layer or drug efflux pumps, both of which function to exclude antibio ...	2000	11021941
the vibrio cholerae toxr/tcpp/toxt virulence cascade: distinct roles for two membrane-localized transcriptional activators on a single promoter.	toxr is required in vibrio cholerae for transcriptional activation of the toxt gene, the protein product of which activates numerous genes involved in virulence. although toxr cannot activate the toxt promoter in escherichia coli, the products of the tcpph operon are shown here to activate the toxt promoter, and co-expression with toxrs enhances activation. an identical pattern was seen in a deltatcppdeltatoxr strain of v. cholerae when tcpph or toxrs was expressed from plasmids. although overex ...	2000	11029691
[molecular epidemiology of large bacterial endemics in sub-saharan africa].	over the past decades, the differentiation of bacterial strains for epidemiological purposes had been based on conventional phenotypic characters. more recently, methods studying the directly coded molecules or semantides (nucleic acids or proteins) have allowed, concomitantly with the technical progresses of electrophoresis, the description of stable, discriminant, reproducible markers, which were applicable to large series of isolates. initially applied to study nosocomial infections in indust ...	2000	11030062
in vivo covalent cross-linking of cellular actin by the vibrio cholerae rtx toxin.	enteric pathogens often export toxins that elicit diarrhea as a part of the etiology of disease, including toxins that affect cytoskeletal structure. recently, we discovered that the intestinal pathogen vibrio cholerae elicits rounding of epithelial cells that is dependent upon a gene we designated rtxa. here we investigate the association of rtxa with the cell-rounding effect. we find that v. cholerae exports a large toxin, rtx (repeats-in-toxin) toxin, to culture supernatant fluids and that th ...	2000	11032799
construction of a vibrio cholerae vaccine candidate using transposon delivery and flp recombinase-mediated excision.	recent efforts to develop a vaccine against the diarrheal disease cholera have focused on the use of live attenuated strains of the causative organism, vibrio cholerae. the ogawa lipopolysaccharide phenotype is expressed by many epidemic strains, and motility defects reduce the risk of reactive diarrhea in vaccine recipients. we therefore converted a motile inaba(+) vaccine candidate, peru-2, to a nonmotile ogawa(+) phenotype using a mariner-based transposon carrying rfbt, the gene required for ...	2000	11035750
construction and characterization of a nonproliferative el tor cholera vaccine candidate derived from strain 638.	in recent clinical assays, our cholera vaccine candidate strain, vibrio cholerae 638 el tor ogawa, was well tolerated and immunogenic in cuban volunteers. in this work we describe the construction of 638t, a thymidine auxotrophic version of improved environmental biosafety. in so doing, the thya gene from v. cholerae was cloned, sequenced, mutated in vitro, and used to replace the wild-type allele. except for its dependence on thymidine for growth in minimal medium, 638t is essentially indisting ...	2000	11035753
association of protease activity in vibrio cholerae vaccine strains with decreases in transcellular epithelial resistance of polarized t84 intestinal epithelial cells.	culture supernatants prepared from reactogenic strains of vibrio cholerae cause a decrease in the transcellular epithelial resistance of t84 intestinal cells. this decrease correlates with the presence of hemagglutinin/protease but not with the presence of other potential accessory toxins or proteases. these data suggest a possible role for hemagglutinin/protease in reactogenicity, although other factors may also contribute.	2000	11035765
a novel action of the proton pump inhibitor rabeprazole and its thioether derivative against the motility of helicobacter pylori.	the motility of helicobacter pylori was maximum at 37 degrees c and at ph 6. a newly developed proton pump inhibitor, rabeprazole (rpz), and its thioether derivative (rpz-th) markedly inhibited the motility of h. pylori. the concentrations of the drug necessary to inhibit 50% of the motility were 0.25, 16, 16, and >64 microgram/ml for rpz-th, rpz, lansoprazole, and omeprazole, respectively. no such inhibitory effects were observed with h(2) blockers or anti-h. pylori agents. the motilities of ca ...	2000	11036024