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red bayberry extract inhibits growth and virulence gene expression of the human pathogen vibrio cholerae. 200818222950
quorum sensing controls biofilm formation in vibrio cholerae through modulation of cyclic di-gmp levels and repression of vpst.two chemical signaling systems, quorum sensing (qs) and 3',5'-cyclic diguanylic acid (c-di-gmp), reciprocally control biofilm formation in vibrio cholerae. qs is the process by which bacteria communicate via the secretion and detection of autoinducers, and in v. cholerae, qs represses biofilm formation. c-di-gmp is an intracellular second messenger that contains information regarding local environmental conditions, and in v. cholerae, c-di-gmp activates biofilm formation. here we show that hapr, ...200818223081
identification and functional characterization of gene components of type vi secretion system in bacterial genomes.a new secretion system, called the type vi secretion system (t6ss), was recently reported in vibrio cholerae, pseudomonas aeruginosa and burkholderia mallei. a total of 18 genes have been identified to be belonging to this secretion system in v. cholerae. here we attempt to identify presence of t6ss in other bacterial genomes. this includes identification of orthologous sequences, conserved motifs, domains, families, 3d folds, genomic islands containing t6ss components, phylogenetic profiles and ...200818698408
antibacterial properties of fish mucus from channa punctatus and cirrhinus mrigala.extracts and preparations made from the animal origin were used extensively in folk and modern medicine for treating many human diseases. in the present study efforts have been made to find the antimicrobial effect of the mucus of two bottom dwelling fresh water fishes namely, channa punctatus and cirrhinus mrigala. fish mucus were tested against ten pathogenic bacteria such as escherichia coli, klebsiella oxytoca, klebsiella pneumoniae, lactobacillus vulgaris, proteus mirabilis, pseudomonas aer ...200818700685
crystal structures of c4-dicarboxylate ligand complexes with sensor domains of histidine kinases dcus and dctb.two-component signaling systems allow bacteria to adapt to changing environments. typically, a chemical or other stimulus is detected by the periplasmic sensor domain of a transmembrane histidine kinase sensor, which in turn relays a signal through a phosphotransfer cascade to the cognate cytoplasmic response regulator. such systems lead ultimately to changes in gene expression or cell motility. mechanisms of ligand binding and signal transduction through the cell membrane in histidine kinases a ...200818701447
inapparent infections and cholera dynamics.in many infectious diseases, an unknown fraction of infections produce symptoms mild enough to go unrecorded, a fact that can seriously compromise the interpretation of epidemiological records. this is true for cholera, a pandemic bacterial disease, where estimates of the ratio of asymptomatic to symptomatic infections have ranged from 3 to 100 (refs 1-5). in the absence of direct evidence, understanding of fundamental aspects of cholera transmission, immunology and control has been based on ass ...200818704085
essential genes in salmonella enteritidis as identified by tnaraout mutagenesis.tnaraout is a mariner-based transposon containing an arabinose-inducible promoter p(bad) facing outward. tnaraout mutagenesis previously used to identify essential genes in vibrio cholerae can also be used to identify in vitro essential genes in salmonella enteritidis. a mutant screen was conducted based on the assumption that a mutant-harboring tnaraout insertion in the promoter region of an essential gene should exhibit arabinose-dependent growth phenotype. among five isolated mutants with suc ...200818704577
class 1 integrons and sxt elements conferring multidrug resistance in vibrio cholerae o1 strains associated with a recent large cholera outbreak in orissa, eastern india. 200818706789
interplay between cyclic amp-cyclic amp receptor protein and cyclic di-gmp signaling in vibrio cholerae biofilm formation.vibrio cholerae is a facultative human pathogen. the ability of v. cholerae to form biofilms is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. formation of mature biofilms requires the production of extracellular matrix components, including vibrio polysaccharide (vps) and matrix proteins. biofilm formation is positively controlled by the transcriptional regulators vpsr and vpst and is negatively regulated by the ...200818708497
vibrio cholerae o139 multiple-drug resistance mediated by yersinia pestis pip1202-like conjugative plasmids.a conjugative plasmid, pmrv150, which mediated multiple-drug resistance (mdr) to at least six antibiotics, including ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole, was identified in a vibrio cholerae o139 isolate from hangzhou, eastern china, in 2004. according to partial pmrv150 dna sequences covering 15 backbone regions, the plasmid is most similar to pip1202, an inca/c plasmid in an mdr yersinia pestis isolate from a madagascar bubonic ...200818710912
bacterial exotoxins downregulate cathelicidin (hcap-18/ll-37) and human beta-defensin 1 (hbd-1) expression in the intestinal epithelial cells.cathelicidin (hcap-18/ll-37) and beta-defensin 1 (hbd-1) are human antimicrobial peptides (amps) with high basal expression levels, which form the first line of host defence against infections over the epithelial surfaces. the antimicrobial functions owe to their direct microbicidal effects as well as the immunomodulatory role. pathogenic microorganisms have developed multiple modalities including transcriptional repression to combat this arm of the host immune response. the precise mechanisms a ...200818717821
increased isolation of vibrio cholerae o1 serotype inaba over serotype ogawa in pakistan.although the predominant vibrio cholerae serotype in pakistan is ogawa and serotype inaba is rare, there has been a significant increase in the isolation of inaba in our referral laboratory in karachi. this paper reports this observation and further analysis of previous cholera data from 1993 to 2005 to assess the trend of occurrence and resistance pattern of v. cholerae strains. from january to september 2005, 245/3292 (7.4%) specimens yielded growth of v. cholerae. of these, 243 were serotype ...200818720620
cholera toxin-specific memory b cell responses are induced in patients with dehydrating diarrhea caused by vibrio cholerae o1.infection with vibrio cholerae induces durable immunity against subsequent disease, a process hypothesized to reflect anamnestic immune responses at the intestinal mucosa. the presence of antigen-specific memory b cells may therefore be a more direct measure of protection than serum antibody responses.200818729782
vibrio cholerae o1 from accra, ghana carrying a class 2 integron and the sxt element.vibrio cholerae o1 from a 2006 outbreak in accra were commonly resistant to multiple antimicrobials and, in particular, to trimethoprim/sulfamethoxazole, drugs commonly used in the treatment of cholera. we sought to determine the genetic basis for trimethoprim/sulfamethoxazole resistance in outbreak isolates.200818755696
[characterization of the adhesive activity of cholera vibrions in mammalian red blood cells as an additional test for assessment of their epidemic significance].the in vitro study of the adhesive properties of v. cholerae eltor and v. cholerae o139 on a model of mammalian red blood cells revealed a correlation of their adhesive properties, the presence of the ctx ab, tcpa genes, and their hemolytic activity when blood group a (ii) red blood cells were used. in the latter case, the strains having the characteristics of ctx(+) tcp(+) hly(-) were ascertained to have a mean adhesive value (mav) of > 1.5, a red blood cell involvement coefficient (rbcic) of > ...200818756736
[variation in the genome of ctxphi prophage of vibrio cholerae biovar el tor caused by tn5-mob transposon].a key pathogenicity factor of the cholera etiologic agent is cholera toxin (ct) whose synthesis is encoded by the ctxab operon forming apart of the ctxphi ptophage. alterations in the virulent properties of the cholera vibrios are based on the variability of the ctxphi prophage containing the genes for ctxab, zot, ace, cep, orfu, and psh in its core region. at the same time, the mechanism of the porophage genome reorganization needs further and more profound analysis. the goal of this work was t ...200818756818
the extracellular nuclease dns and its role in natural transformation of vibrio cholerae.free extracellular dna is abundant in many aquatic environments. while much of this dna will be degraded by nucleases secreted by the surrounding microbial community, some is available as transforming material that can be taken up by naturally competent bacteria. one such species is vibrio cholerae, an autochthonous member of estuarine, riverine, and marine habitats and the causative agent of cholera, whose competence program is induced after colonization of chitin surfaces. in this study, we in ...200818757542
comparison of distribution of virulence determinants in clinical and environmental isolates of vibrio cholera.the virulence of a pathogenic vibrio cholerae is dependent on a discrete set of genetic determinants. in this study, we determined the distribution of virulence determinants among the clinical and environmental isolates of v. cholerae.200818762819
is hiv infection associated with an increased risk for cholera? findings from a case-control study in mozambique.as residents of sub-saharan africa are at high risk for hiv and cholera, it is biologically plausible that immune suppression caused by hiv infection predisposes to cholera. our aim was to assess the potential association between both diseases.200818331384
microchip electrophoresis for specific gene detection of the pathogenic bacteria v. cholerae by circle-to-circle amplification.we have developed a new method for a fast and precise analysis of circle-to-circle amplification (c2ca) product for specific gene detection by microchip electrophoresis. in this method, we have added a new enzymatic step to the c2ca reaction, which could be carried out isothermally at 37 degrees c. compared to the original single-stranded dna, the double-stranded dna that is produced by this enzymatic reaction is more reliable for analysis by microchip electrophoresis. c2ca product was detected ...200818332538
rapid spread of vibrio cholerae o1 throughout kenya, 2005.between january and june 2005, 5 distinct cholera outbreaks occurred in kenya. overall, 990 cases and 25 deaths (2.5%) were reported. four outbreaks occurred in towns along major highways, and 1 occurred in a refugee camp near the sudanese border, accessible to nairobi by daily flights. matched case-control studies from 2 outbreaks showed that failure to treat drinking water and storing drinking water in wide-mouthed containers were significantly associated with disease. isolates from all 5 outb ...200818337355
production and sequence validation of a complete full length orf collection for the pathogenic bacterium vibrio cholerae.cholera, an infectious disease with global impact, is caused by pathogenic strains of the bacterium vibrio cholerae. high-throughput functional proteomics technologies now offer the opportunity to investigate all aspects of the proteome, which has led to an increased demand for comprehensive protein expression clone resources. genome-scale reagents for cholera would encourage comprehensive analyses of immune responses and systems-wide functional studies that could lead to improved vaccine and th ...200818337508
overview of the inactivation by 254 nm ultraviolet radiation of bacteria with particular relevance to biodefense.our goal was to ultimately predict the sensitivity of untested bacteria (including those of biodefense interest) to ultraviolet (uv) radiation. in this study, we present an overview and analysis of the relevant 254 nm data previously reported and available in the literature. the amount of variability in this data prevented us from determining an "average" response for any bacterium. therefore, we developed particular selection criteria to include the data in our analysis and suggested future gui ...200818627518
functional independence of a variant luxopl91 from a non-o1 non-o139 vibrio cholerae over the activity of csra and fis. 200818628511
intra-family transmission of vibrio cholerae during a cholera epidemic in rural south-southern nigeria. 200818628554
trend of antibiotic resistance of vibrio cholerae strains from east delhi.epidemics of cholera caused by toxigenic vibrio cholerae o1 and o139 (bengal strain) represent a major public health problem in most developing countries. in view of the reported shift in epidemiology and pattern of antibiotic resistance in this was study carried out to assess the development of resistance to essential drugs like fluoroquinolones during treatment of cholera and cholera like cases in delhi.200818653912
simultaneous detection of six human diarrheal pathogens by using dna microarray combined with tyramide signal amplification.multiplex pcr and dna microarray were combined with tyramide signal amplification (tsa) to develop a reliable method suitable for simultaneous detection of six species of human diarrheal pathogens (yersinia enterocolitica, shigella spp, salmonella typhi, brucella spp, vibrio cholera and escherichia coli o157:h7). meanwhile, our method could distinguish v. cholera serotype o1 from o139, and o157:h7 from o157: non-h7. this assay conferred a specificity of 100% for target pathogens. the limit of de ...200818655810
a new variant of vibrio cholerae o1 el tor causing cholera in india. 200818657323
a cluster of vibrio cholerae o1 infections in french travelers to rajasthan (india), may 2006.a woman aged 60 years was hospitalized for vibrio cholerae serogroup o1 cholera. twenty-six fellow travelers and 48 health care workers who cared for the patient were individually traced and contacted. of the 23/27 travelers with diarrhea during the trip, 4 presented antibodies. there was no person-to-person transmission.200818666928
cholera, 2007. 200818668979
comparison of detection and signal amplification methods for dna microarrays.one of the factors limiting the use of dna microarray technology for the detection of pathogenic organisms from clinical and environmental matrices has been inadequate assay sensitivity. to assess the effectiveness of post-hybridization secondary detection steps to enhance the sensitivity of dna microarray-based pathogen detection, we evaluated a panel of 11 commercial and novel hybridization detection and signal amplification methods (direct labeling, indirect aminoallyl labeling, antibody, dna ...200818675897
the vibrio cholerae hybrid sensor kinase vies contributes to motility and biofilm regulation by altering the cyclic diguanylate level.phosphorelay systems are important mediators of signal transduction during bacterial adaptation to new environments. previously we described the viesab operon, encoding a putative three-protein component phosphorelay involved in regulating vibrio cholerae virulence gene expression. at least part of the regulatory activity of viesab is exerted through the cyclic diguanylate (c-di-gmp)-degrading activity of the putative response regulator viea. so far no direct evidence that viesab encodes a phosp ...200818676667
immunization with vibrio cholerae outer membrane vesicles induces protective immunity in mice.the gram-negative bacterium vibrio cholerae releases outer membrane vesicles (omvs) during growth. in this study, we immunized female mice by the intranasal, intragastric, or intraperitoneal route with purified omvs derived from v. cholerae. independent of the route of immunization, mice induced specific, high-titer immune responses of similar levels against a variety of antigens present in the omvs. after the last immunization, the half-maximum total immunoglobulin titer was stable over a 3-mon ...200818678672
a new vibrio cholerae srna modulates colonization and affects release of outer membrane vesicles.we discovered a new small non-coding rna (srna) gene, vrra of vibrio cholerae o1 strain a1552. a vrra mutant overproduces ompa porin, and we demonstrate that the 140 nt vrra rna represses ompa translation by base-pairing with the 5' region of the mrna. the rna chaperone hfq is not stringently required for vrra action, but expression of the vrra gene requires the membrane stress sigma factor, sigma(e), suggesting that vrra acts on ompa in response to periplasmic protein folding stress. we also ob ...200818681937
[distribution and molecular characteristics of vibrio cholerae serogroups o1 and o139 isolates in estuary of pearl river].through systematic monitoring of the number and strain types of o1 and o139 vibrio cholerae in the pearl river estuary waters to analyze it's relevance with the temperature of environment, and the relevance between strains in water and isolates during outbreaks and epidemics as well as to estimate the methods used for environmental water detection and the potential role in cholera surveillance program.200818686854
effectiveness and kinetics of ferrate as a disinfectant for ballast water.this study examined whether ferrate could meet the international standards for successful ballast water treatment, including final concentrations of less than 1 cfu/ml of enterococci, less than 2.5 cfu/ml of escherichia coli, and less than 1 cfu/100 ml of vibrio cholerae. pure cultures of e. coli, klebsiella pneumoniae, and v. cholerae, and a mixed culture of enterococcus faecium and e. faecilis were grown in saline solution to simulate ballast water and were treated with dosages of ferrate rang ...200818686931
acquisition of classical ctx prophage from vibrio cholerae o141 by el tor strains aided by lytic phages and chitin-induced competence.the el tor biotype of vibrio cholerae o1, causing the current seventh pandemic of cholera, has replaced the classical biotype, which caused the sixth pandemic. the ctx prophages encoding cholera toxin in the two biotypes have distinct repressor (rstr) genes. recently, new variants of el tor strains that carry the classical type (ctx(class)) prophage have emerged. these "hybrid" strains apparently originate through lateral gene transfer and recombination events. to explore possible donors of the ...200818689675
role of cyclic di-gmp during el tor biotype vibrio cholerae infection: characterization of the in vivo-induced cyclic di-gmp phosphodiesterase cdpa.in vibrio cholerae, the second messenger cyclic di-gmp (c-di-gmp) positively regulates biofilm formation and negatively regulates virulence and is proposed to play an important role in the transition from persistence in the environment to survival in the host. herein we describe a characterization of the infection-induced gene cdpa, which encodes both ggdef and eal domains, which are known to mediate diguanylate cyclase and c-di-gmp phosphodiesterase (pde) activities, respectively. cdpa is shown ...200818227161
changing patterns of vibrio cholerae in sevagram between 1990 and 2005.a retrospective analysis was done to note changes in prevalence, distribution of biotypes, serotypes, antibiotic susceptibility patterns and phage types of vibrio cholerae isolated in mahatma gandhi institute of medical sciences, sevagram over a period of 16 years.200818227596
application of dna-based methods in typing vibrio cholerae strains.molecular biology-based techniques based on microbial genotype or dna sequence have emerged as a basic tool in biological research and in the establishment of large databases of characterized organisms. genotyping methods have the potential to provide information on subtypes of the organism and their source and/or origin of infection, and to recognize particularly virulent strains of the organism and monitor vaccination programs. pulsed-field gel electrophoresis, ribotyping, ctx typing, amplifie ...200818230037
the evolution of quorum sensing in bacterial biofilms.bacteria have fascinating and diverse social lives. they display coordinated group behaviors regulated by quorum-sensing systems that detect the density of other bacteria around them. a key example of such group behavior is biofilm formation, in which communities of cells attach to a surface and envelope themselves in secreted polymers. curiously, after reaching high cell density, some bacterial species activate polymer secretion, whereas others terminate polymer secretion. here, we investigate ...200818232735
structure of the minor pseudopilin epsh from the type 2 secretion system of vibrio cholerae.many gram-negative bacteria use the multi-protein type ii secretion system (t2ss) to selectively translocate virulence factors from the periplasmic space into the extracellular environment. in vibrio cholerae the t2ss is called the extracellular protein secretion (eps) system,which translocates cholera toxin and several enzymes in their folded state across the outer membrane. five proteins of the t2ss, the pseudopilins, are thought to assemble into a pseudopilus, which may control the outer memb ...200818241884
vibrios in association with sedimentary crustaceans in three beaches of the northern adriatic sea (italy).in the marine environment, vibrios adhere to a number of substrates including chitin-rich organisms such as crustaceans. their wide diffusion in coastal waters and pathogenic potential require knowledge of the lifestyle and environmental reservoirs of these bacteria. to test the presence of culturable vibrios in coastal areas and their association with benthic crustaceans, vibrios were isolated from water, sediments and crustaceans (copepods and anphipods) at three stations placed in front of he ...200818243247
rapid growth of planktonic vibrio cholerae non-o1/non-o139 strains in a large alkaline lake in austria: dependence on temperature and dissolved organic carbon quality.vibrio cholerae non-o1/non-o139 strains have caused several cases of ear, wound, and blood infections, including one lethal case of septicemia in austria, during recent years. all of these cases had a history of local recreational activities in the large eastern austrian lake neusiedler see. thus, a monitoring program was started to investigate the prevalence of v. cholerae strains in the lake over several years. genetic analyses of isolated strains revealed the presence of a variety of pathogen ...200818245230
gdp-perosamine synthase: structural analysis and production of a novel trideoxysugar.perosamine or 4-amino-4,6-dideoxy- d-mannose is an unusual sugar found in the o-antigens of some gram-negative bacteria such as vibrio cholerae o1 (the causative agent of cholera) or escherichia coli o157:h7 (the leading cause of food-borne illnesses). it and similar deoxysugars are added to the o-antigens of bacteria via the action of glycosyltransferases that employ nucleotide-linked sugars as their substrates. the focus of this report is gdp-perosamine synthase, a plp-dependent enzyme that ca ...200818247575
vibrio vulnificus rtxe is important for virulence, and its expression is induced by exposure to host cells.numerous secreted virulence factors have been proposed to account for the fulminating and destructive nature of vibrio vulnificus infections. a mutant of v. vulnificus that exhibited less cytotoxicity to int-407 human intestinal epithelial cells was screened from a library of mutants constructed by random transposon mutagenesis. a transposon-tagging method was used to identify and clone an open reading frame encoding an rtx toxin secretion atp binding protein, rtxe, from v. vulnificus. the deduc ...200818250174
virulence factor rtx in legionella pneumophila, evidence suggesting it is a modular multifunctional protein.the repeats in toxin (rtx) are an important pathogenicity factor involved in host cells invasion of legionella pneumophila and other pathogenic bacteria. its role in escaping the host immune system and cytotoxic activity is well known. its repeated motives and modularity make rtx a multifunctional factor in pathogenicity.200818194518
a negative feedback loop involving small rnas accelerates vibrio cholerae's transition out of quorum-sensing mode.quorum sensing is a cell-to-cell communication process that allows bacteria to measure their population numbers and to synchronously alter gene expression in response to changes in cell population density. at the core of the vibrio cholerae quorum-sensing signal transduction pathway lie four redundant small rnas (srnas), named the quorum regulatory rnas (qrr1-4). expression of qrr1-4 is cell population density-dependent due to a requirement for the quorum-sensing controlled phosphorylated respon ...200818198339
persistence and degradation of maize-expressed vaccine protein, escherichia coli heat-labile enterotoxin subunit b, in soil and water.transgenic plants represent an innovative platform for the cost-effective large-scale production of various pharmaceutical proteins. the eventual open-field production of plant-made pharmaceuticals (pmps) requires risk assessment to determine the potential for harm to the surrounding ecosystem. in the present study, the environmental persistence of a transgenic maize-expressed antigen, escherichia coli heat-labile enterotoxin subunit b (ltb), was studied under laboratory conditions. to semiquant ...200818198938
foodborne disease outbreaks caused by sucrose-nonfermenting and beta-galactosidase-deficient variants of vibrio cholerae.we reported four foodborne disease outbreaks in taiwan caused by sucrose-nonfermenting and by beta-galactosidase-deficient variants of non-o1, non-o139 vibrio cholerae. the sucrose-nonfermenting vibrios collected from three outbreaks were biochemically identified to be v. mimicus and the beta-galactosidase-deficient vibrios from an outbreak to be v. alginolyticus. however, molecular methods including dna-dna hybridization, fatty acid profile analysis, and sequence analysis of 16s rrna, oric, pyr ...200818164089
role of escherichia coli in acute diarrhoea in tribal preschool children of central india.five hundred and eighty preschool children belonging to tribal areas of madhya pradesh were followed up daily for the presence of diarrhoea for a period of 1 year. in all, 1236 episodes of diarrhoea were recorded with an average of 2.13 episodes per child per year. stool samples were collected during 780 episodes. they were cultured to isolate escherichia coli as well as non-e. coli enteropathogens. ten different genes were detected to identify all diarrhoeagenic e. coli using multiplex polymera ...200818173783
functional role of conserved residues in the characteristic secretion ntpase motifs of the pseudomonas aeruginosa type iv pilus motor proteins pilb, pilt and pilu.type iv pili are retractable protein fibres used by many bacterial pathogens for adherence, twitching motility, biofilm development and host colonization. in pseudomonas aeruginosa, pilb and pilt are bipolar proteins belonging to the secretion ntpase superfamily, and power pilus extension and retraction, respectively, while the unipolar pilt paralogue pilu supports pilus retraction in an unknown manner. assay of purified 6xhis-tagged pilb, pilt and pilu from p. aeruginosa showed that all three p ...200818174131
decreased potency of the vibrio cholerae sheathed flagellum to trigger host innate immunity.vibrio cholerae is a monoflagellated gram-negative bacterium that causes the severe diarrheal disease cholera. in contrast to salmonella enterica serovar typhimurium infection, which is accompanied by both acute diarrhea and high-level inflammation, v. cholerae infection is largely noninflammatory in human hosts. bacterial flagella are composed of flagellin, a highly conserved protein that is also a target of the innate immune response. because the v. cholerae flagellum is covered by a sheath, w ...200818174340
post-transcriptional cross-talk between pro- and anti-colonization pili biosynthesis systems in vibrio cholerae.the pathogen vibrio cholerae modulates the expression of many genes in order to transition from its environmental reservoir to its niche in the human host. among these are genes encoding two related type iv pili, the mannose-sensitive haemagglutinin (msha) pilus, which aids v. cholerae persistence in aquatic environments but causes clearance of bacteria by host immune defences, and the toxin co-regulated pilus (tcp) required for colonization. these antagonistic effects are resolved transcription ...200818179420
isolation and characterization of vibrio tubiashii outer membrane proteins and determination of a toxr homolog.outer membrane proteins (omps) expressed by vibrio tubiashii under different environmental growth conditions were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, n-terminal amino acid sequencing, and pcr analyses. results showed the presence of a 38- to 40-kda ompu-like protein and ompu gene, a maltoporin-like protein, several novel omps, and a regulatory toxr homolog.200818083865
assessment by electron-microscopy of recombinant vibrio cholerae and salmonella vaccine strains expressing enterotoxigenic escherichia coli-specific surface antigens.diarrhoea caused by enterotoxigenic escherichia coli (etec) requires adhesion of microorganisms to enterocytes. hence, a promising approach to immunoprophylaxis is to elicit antibodies against colonisation factor antigens (cfas). genes encoding the most prevalent etec-specific surface antigens were cloned into vibrio cholerae and salmonella vaccine strains. expression of surface antigens was assessed by electron-microscopy. whereas negative staining was effective in revealing cfa/i and cs3, but ...200818093230
temperate bacteriophage phio18p from an aeromonas media isolate: characterization and complete genome sequence.a group of 74 aeromonas isolates from surface water of three ponds in bielefeld, germany was screened for prophage induction after uv irradiation. the phage phio18p was induced from the aeromonas media isolate o18. phio18p belongs to the myoviridae phage family. the complete nucleotide sequence of the double stranded dna genome of bacteriophage phio18p consists of 33,985 bp. the genome has 5' protruding cohesive ends of 16 bases. on the phio18p genome 46 open reading frames (orfs) were identifie ...200818096197
hyposialylation of neprilysin possibly affects its expression and enzymatic activity in hereditary inclusion-body myopathy muscle.autosomal recessive hereditary inclusion-body myopathy (h-ibm) is caused by mutations of the udp-n-acetylglucosamine 2-epimerase/n-acetylmannosamine kinase gene, a rate-limiting enzyme in the sialic acid metabolic pathway. previous studies have demonstrated an abnormal sialylation of glycoproteins in h-ibm. h-ibm muscle shows the abnormal accumulation of proteins including amyloid-beta (abeta). neprilysin (nep), a metallopeptidase that cleaves abeta, is characterized by the presence of several n ...200818182043
vibrio cholerae toxin-coregulated pilus structure analyzed by hydrogen/deuterium exchange mass spectrometry.the bacterial pathogen vibrio cholerae uses toxin-coregulated pili (tcp) to colonize the human intestine, causing the severe diarrheal disease cholera. tcp are long, thin, flexible homopolymers of the tcpa subunit that self-associate to hold cells together in microcolonies and serve as the receptor for the cholera toxin phage. to better understand tcp's roles in pathogenesis, we characterized its structure using hydrogen/deuterium exchange mass spectrometry and computational modeling. we show th ...200818184591
zinc supplementation in children with cholera in bangladesh: randomised controlled trial.to investigate the impact of zinc supplementation in children with cholera.200818184631
presence of quorum-sensing systems associated with multidrug resistance and biofilm formation in bacteroides fragilis.bacteroides fragilis constitutes 1-2% of the natural microbiota of the human digestive tract and is the predominant anaerobic opportunistic pathogen in gastrointestinal infections. most bacteria use quorum sensing (qs) to monitor cell density in relation to other cells and their environment. in gram-negative bacteria, the luxri system is common. the luxr gene encodes a transcriptional activator inducible by type i acyl-homoserine lactone autoinducers (e.g., n-[3-oxohexanoyl] homoserine lactone a ...200818188535
construction of non-toxic escherichia coli and vibrio cholerae strains expressing high and immunogenic levels of enterotoxigenic e. coli colonization factor i fimbriae.to express high quantities of colonization factor antigen i (cfa/i) derived from enterotoxigenic escherichia coli (etec) for use in etec vaccines, the entire cfa/i operon consisting of four genes (cfa-a, -b, -c, -e) was cloned into plasmid expression vectors that could be maintained either with or without antibiotic selection. expression from the powerful tac promoter was under the control of the laciq repressor present on the plasmids. fimbriae were expressed on the surface of both a non-toxige ...200818191006
development of a multiplex single-tube nested pcr (mstnpcr) assay for vibrio cholerae o1 detection.a multiplex nested pcr method for detection of vibrio cholerae o1 using a single tube was developed (mstnpcr). firstly, single-tube nested pcr (stnpcr) with primers directed to ctxa gene was standardized, and its detection limit was compared to simple pcr and two-step nested pcr. secondly, primers directed to rfbn gene were added to the reaction. the detection limit of the multiplex reaction was determined using v. cholerae o1 dna and v. cholerae o1 grown in alkaline peptone water (apw). stnpcr ...200818191489
antibacterial activities and cytotoxicity of terpenoids isolated from spirostachys africana.spirostachys africana sond. stem bark is used traditionally for the treatment of diarrhoea and dysentery in limpopo province of south africa. bioassay-guided fractionation of ethanolic extract from bark of spirostachys africana led to the isolation of four known compounds, two triterpenoids, compound 1 [d-friedoolean-14-en-oic acid (3-acetyl aleuritolic acid)] and compound 2 (lupeol), and two diterpenes, compound 3 [ent-2,6alpha-dihydroxy-norbeyer-1,4,15-trien-3-one (diosphenol 2)] and compound ...200818191928
occurrence and expression of luminescence in vibrio cholerae.several species of the genus vibrio, including vibrio cholerae, are bioluminescent or contain bioluminescent strains. previous studies have reported that only 10% of v. cholerae strains are luminescent. analysis of 224 isolates of non-o1/non-o139 v. cholerae collected from chesapeake bay, md, revealed that 52% (116/224) were luminescent when an improved assay method was employed and 58% (130/224) of isolates harbored the luxa gene. in contrast, 334 non-o1/non-o139 v. cholerae strains isolated fr ...200818065611
synthesis and use of mechanism-based protein-profiling probes for retaining beta-d-glucosaminidases facilitate identification of pseudomonas aeruginosa nagz.the nagz class of retaining exo-glucosaminidases play a critical role in peptidoglycan recycling in gram-negative bacteria and the induction of resistance to beta-lactams. here we describe the concise synthesis of 2-azidoacetyl-2-deoxy-5-fluoro-beta-d-glucopyranosyl fluoride as an activity-based proteomics probe for profiling these exo-glycosidases. this active-site directed reagent covalently inactivates this class of retaining n-acetylglucosaminidases with exquisite selectivity by stabilizing ...200818067297
construction of cholera toxin b subunit-producing vibrio cholerae strains using the mariner-frt transposon delivery system.the most widely used oral whole-cell-recombinant b subunit cholera vaccine contains the nontoxic cholera toxin b subunit (ctxb) and either heat- or formalin-killed vibrio cholerae o1 strains. vibrio cholerae o1 strains in the vaccine provide antibacterial immunity, and ctxb contributes to the vaccine's efficacy by stimulating production of anti-ctxb antibody. various attempts have been made to increase ctxb production. in this study, the mariner-frt transposon delivery system developed by chiang ...200818070076
homology modeling of hemagglutinin/protease [ha/p (vibriolysin)] from vibrio cholerae: sequence comparision, residue interactions and molecular mechanism.vibrio cholerae produces a zinc-containing and calcium-stabilized soluble hemagglutinin/protease, which has been earlier shown to have the ability to cleave several physiologically important substrates including mucin, fibronectin and lactoferin. this study presents homology modeling of hemagglutinin/protease (vibriolysin) from vibrio cholerae in the presence of inhibitor hpi [n-(1-carboxy-3-phenylpropyl)-phenylalanyl-alpha-aspargine]. the 3d structure was predicted based on its sequence homolog ...200818074211
chemical basis of glycine riboswitch cooperativity.the glycine binding riboswitch forms a unique tandem aptamer structure that binds glycine cooperatively. we employed nucleotide analog interference mapping (naim) and mutagenesis to explore the chemical basis of glycine riboswitch cooperativity. based on the interference pattern, at least two sites appear to facilitate cooperative tertiary interactions, namely, the minor groove of the p1 helix from aptamer 1 and the major groove of the p3a helix from both aptamers. mutation of these residues alt ...200818042658
structure discrimination for the c-terminal domain of escherichia coli trigger factor in solution.nmr measurements can give important information on solution structure, without the necessity for a full-scale solution structure determination. the c-terminal protein binding domain of the ribosome-associated chaperone protein trigger factor is composed of non-contiguous parts of the polypeptide chain, with an interpolated prolyl isomerase domain. a construct of the c-terminal domain of escherichia coli trigger factor containing residues 113-149 and 247-432, joined by a gly-ser-gly-ser linker, i ...200818043871
molecular characterization of a functional type vi secretion system from a clinical isolate of aeromonas hydrophila.our laboratory recently molecularly characterized the type ii secretion system (t2ss)-associated cytotoxic enterotoxin (act) and the t3ss-secreted aexu effector from a diarrheal isolate ssu of aeromonas hydrophila. the role of these toxin proteins in the pathogenesis of a. hydrophila infections was subsequently delineated in in vitro and in vivo models. in this study, we characterized the new type vi secretion system (t6ss) from isolate ssu of a. hydrophila and demonstrated its role in bacterial ...200818037263
the crystal structure of a binary complex of two pseudopilins: epsi and epsj from the type 2 secretion system of vibrio vulnificus.type ii secretion systems (t2ss) translocate virulence factors from the periplasmic space of many pathogenic bacteria into the extracellular environment. the t2ss of vibrio cholerae and related species is called the extracellular protein secretion (eps) system that consists of a core of multiple copies of 11 different proteins. the pseudopilins, epsg, epsh, epsi, epsj and epsk, are five t2ss proteins that are thought to assemble into a pseudopilus, which is assumed to interact with the outer mem ...200818022192
exploiting cholera vaccines as a versatile antigen delivery platform.the development of safe, immunogenic and protective cholera vaccine candidates makes possible their use as a versatile antigen delivery platform. foreign antigens can be delivered to the immune system with cholera vaccines by expressing heterologous antigens in live attenuated vectors, as fusion proteins with cholera toxin subunits combined with inactivated vibrio cholerae whole cells or by exposing them on the surface of v. cholerae ghosts. progress in our understanding of the genes expressed b ...200818008168
vibrio cholerae fabv defines a new class of enoyl-acyl carrier protein reductase.enoyl-acyl carrier protein (acp) reductase catalyzes the last step of the fatty acid elongation cycle. the paradigm enoyl-acp reductase is the fabi protein of escherichia coli that is the target of the antibacterial compound, triclosan. however, some gram-positive bacteria are naturally resistant to triclosan due to the presence of the triclosan-resistant enoyl-acp reductase isoforms, fabk and fabl. the genome of the gram-negative bacterium, vibrio cholerae lacks a gene encoding a homologue of a ...200818032386
vibrio vulnificus rtx toxin kills host cells only after contact of the bacteria with host cells.vibrio vulnificus causes acute cell death and a fatal septicaemia. in this study, we show that contact with host cells is a prerequisite to the acute cytotoxicity. we screened transposon mutants defective in the contact-dependent cytotoxicity. two mutants had insertions within two open reading frames in a putative rtx toxin operon, the rtxa1 or rtxd encoding an rtx toxin (4701 amino acids) or an abc type transporter (467 amino acids). an rtxa1 mutation resulted in a cytotoxicity defect, which wa ...200818005241
the vibrio cholerae cytolysin promotes activation of mast cell (t helper 2) cytokine production.many strains of vibrio cholerae produce a cytolysin (vcc) that forms oligomeric transmembrane pores responsible for vacuolization of several cell types in culture. here we suggest that vcc could contribute to the t helper 2 (th2) response seen in the natural infection; acting through tlr2, vcc enhances mast cells secretion of il-4, il-6 and tnf-alpha by 330-, 290- and 550-fold respectively. moreover, vcc-induced cytokine production is dependent on increased cytosolic ca(2+) and on the presence o ...200818005391
three pathogenicity islands of vibrio cholerae can excise from the chromosome and form circular intermediates.vibrio pathogenicity island-2 (vpi-2) is a 57-kb region integrated at a transfer rna (trna)-serine locus that encompasses vc1758 to vc1809 on the v. cholerae n16961 genome and is present in pandemic isolates. vpi-2 encodes a p4-like integrase, a restriction modification system, a mu phage-like region, and a sialic acid metabolism region, as well as neuraminidase (vc1784), which is a glycosylhydrolase known to release sialic acid from sialoglycoconjugates to unmask gm1 gangliosides, the receptor ...200817993521
molecular characterization of vibrio cholerae deltarela deltaspot double mutants.in escherichia coli cellular levels of pppgpp and ppgpp, collectively called (p)ppgpp, are maintained by the products of two genes, rela and spot. like e. coli, vibrio cholerae also possesses rela and spot genes. here we show that similar to e. coli, v. cholerae deltarela cells can accumulate (p)ppgpp upon carbon starvation but not under amino acid starved condition. although like in e. coli, the spot gene function was found to be essential in v. cholerae rela (+ )background, but unlike e. coli, ...200817968531
a potential epidemic factor from the bacteria, vibrio cholerae wo7.certain species of vibrio cholerae have evolved mechanisms to become pathogenic to humans, with the potential to cause a severe life-threatening diarrheal disease, cholera. cholera can emerge as explosive outbreaks in the human population. v. cholerae illness is produced primarily through the expression of a potent toxin (cholera toxin) within the human intestine. the present study has been carried out on a novel toxin purified from v. cholerae w07, an epidemic cholera strain devoid of cholera t ...200817990031
rna secondary structure regulates the translation of sxy and competence development in haemophilus influenzae.the sxy (tfox) gene product is the central regulator of dna uptake by naturally competent gamma-proteobacteria such as haemophilus influenzae, vibrio cholerae and probably escherichia coli. however, the mechanisms regulating sxy gene expression are not understood despite being key to understanding the physiological role of dna uptake. we have isolated mutations in h. influenzae sxy that greatly elevate translation and thus cause competence to develop in otherwise non-inducing conditions (hyperco ...200817981840
a novel role for enzyme i of the vibrio cholerae phosphoenolpyruvate phosphotransferase system in regulation of growth in a biofilm.glucose is a universal energy source and a potent inducer of surface colonization for many microbial species. highly efficient sugar assimilation pathways ensure successful competition for this preferred carbon source. one such pathway is the phosphoenolpyruvate phosphotransferase system (pts), a multicomponent sugar transport system that phosphorylates the sugar as it enters the cell. components required for transport of glucose through the pts include enzyme i, histidine protein, enzyme iia(gl ...200817981973
lipidation of an flrc-dependent protein is required for enhanced intestinal colonization by vibrio cholerae.vibrio cholerae, the causative agent of cholera, has a sheathed, polar flagellum, and motility has been linked to virulence. an operon with two genes, flgo and flgp (vc2207 and vc2206), is positively regulated by flrc, the activator of class iii flagellar genes. deletion of flgp results in a nonmotile phenotype, demonstrating the requirement of this gene for v. cholerae motility. v. cholerae delta flgp cells synthesize fragile and defective flagella but transcribe flagellar genes similar to the ...200817981980
expression of toxin co-regulated pilus subunit a (tcpa) of vibrio cholerae and its immunogenic epitopes fused to cholera toxin b subunit in transgenic tomato (solanum lycopersicum).for protection against cholera, it is important to develop efficient vaccine capable of inducing anti-toxin as well as anti-colonizing immunity against vibrio cholerae infections. earlier, expression of cholera toxin b subunit (ctb) in tomato was reported by us. in the present investigation, toxin co-regulated pilus subunit a (tcpa), earlier reported to be an antigen capable of providing anti-colonization immunity, has been expressed in tomato. further, to generate more potent combinatorial anti ...200817962948
characterization of cholera outbreak isolates from namibia, december 2006 to february 2007.we report on the first recorded outbreak of cholera in namibia. from december 2006 to february 2007, more than 250 cases of cholera were reported from the omusati and kunene provinces of namibia. however, only nine bacterial isolates were obtainable for analysis. isolates were all identified as vibrio cholerae o1 serotype inaba biotype el tor. all isolates were susceptible to ampicillin, augmentin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, kanamycin, imipenem, ceftriaxone and ...200817963590
recombinant expression of twelve evolutionarily diverse subfamily ialpha aminotransferases.aminotransferases are essential enzymes involved in the central metabolism of all organisms. the ialpha subfamily of aspartate and tyrosine aminotransferases (aatases and tatases) is the best-characterized grouping, but only eight enzymes from this subfamily, representing relatively little sequence diversity, have been experimentally characterized for substrate specificity (i.e., aatase vs. tatase). genome annotation, based on this limited dataset, provides tentative assignments for all sequence ...200817964807
characterization of the enzymatic activity of the actin cross-linking domain from the vibrio cholerae martx vc toxin.vibrio cholerae is a gram-negative bacterial pathogen that exports enterotoxins, which alter host cells through a number of mechanisms resulting in diarrheal disease. among the secreted toxins is the multifunctional, autoprocessing rtx toxin (martx(vc)), which disrupts actin cytoskeleton by covalently cross-linking actin monomers into oligomers. the region of the toxin responsible for cross-linking activity is the actin cross-linking domain (acd). in this study, we demonstrate unambiguously that ...200817951576
effect of the six-mer synthetic peptide (at1002) fragment of zonula occludens toxin on the intestinal absorption of cyclosporin a.zonula occludens toxin (zot) and its biologically active fragment, delta g, have been shown to reversibly open tight junctions (tj) in endothelial and epithelial cells. recently, a six-mer synthetic peptide h-fcigrl-oh (at1002) was identified and synthesized that retains the zot permeating effect on intercellular tj. the objective of this study was to evaluate the biological activity of at1002 on enhancing the oral administration of cyclosporin a (csa). the intestinal permeability enhancing effe ...200817954018
private demand for cholera vaccines in rural matlab, bangladesh.to estimate household willingness to pay (wtp) for cholera vaccines in a rural area of bangladesh, which had participated in a 1985 oral cholera vaccine trial.200817822799
comparison of reversible-jump markov-chain-monte-carlo learning approach with other methods for missing enzyme identification.computational identification of missing enzymes plays a significant role in accurate and complete reconstruction of metabolic network for both newly sequenced and well-studied organisms. for a metabolic reaction, given a set of candidate enzymes identified according to certain biological evidences, a powerful mathematical model is required to predict the actual enzyme(s) catalyzing the reactions. in this study, several plausible predictive methods are considered for the classification problem in ...200817950040
vibrio cholerae cytolysin is essential for high enterotoxicity and apoptosis induction produced by a cholera toxin gene-negative v. cholerae non-o1, non-o139 strain.cholera toxin (ct) gene-negative vibrio cholerae non-o1, non-o139 strains may cause severe diarrhea though their pathogenic mechanism remains unclear. v. cholerae cytolysin (vcc) is a pore-forming exotoxin encoded in the hlya gene of v. cholerae whose contribution to the pathogenesis is not fully understood. in this work, the virulence properties of a ct gene-negative v. cholerae non-o1, non-o139 strain causing a cholera-like syndrome were analyzed. inoculation of rabbit ileal loops with the wil ...200817919878
morphological and immunocytochemical analysis of escherichia coli-specific surface antigens in wildtype strains and in recombinant vibrio cholerae.adhesion is the first step in the pathogenesis of enterotoxigenic escherichia coli infections. the genes encoding the most prevalent adhesion factors cfa/i, cs3 and cs6 were cloned into vibrio cholerae strain cvd 103-hgr and expression of fimbriae was investigated in wildtype and recombinant strains by transmission electron microscopy in conjunction with immunolabelling and negative staining. negative staining was effective in revealing cfa/i and cs3, but not cs6. although morphology of fimbriae ...200817710560
pro-inflammatory feedback activation cycle evoked by attack of vibrio cholerae cytolysin on human neutrophil granulocytes.vibrio cholerae cytolysin (vcc) is a pore-forming toxin that is secreted in precursor form (pro-vcc) and requires proteolytic cleavage in order to attain membrane-permeabilizing properties. pro-vcc can be activated both in solution and membrane-bound state. processing of membrane-bound pro-vcc can in turn be achieved through the action of both cell-associated and soluble proteases. the current investigation describes the interaction of vcc with human neutrophil granulocytes. it is shown that pro ...200817882454
crystal structure of a monoclonal antibody directed against an antigenic determinant common to ogawa and inaba serotypes of vibrio cholerae o1. 200817876834
ingestion of transgenic carrots expressing the escherichia coli heat-labile enterotoxin b subunit protects mice against cholera toxin challenge.diarrheal diseases caused by vibrio cholerae and enterotoxigenic escherichia coli (etec) are worldwide health problems that might be prevented with vaccines based on edible plants expressing the b subunit from either the cholera toxin (ctb) or the e. coli heat labile toxin (ltb). in this work we analyzed the immunity induced in balb/c mice by ingestion of three weekly doses of 10 mug of ltb derived from transgenic carrot material. although the anti-ltb serum immunoglobulin g (igg) and intestinal ...200817874110
intestinal parasitism and vibrio cholerae infection among diarrhoeal patients in kolkata, india.in this study, we have analysed the epidemiological significance of the concurrent infections caused by vibrio cholerae and intestinal parasites among different age groups of hospitalized diarrhoeal patients in kolkata. a total of 3556 stool samples collected during 1996-2004 were screened for vibrios and parasites. the seasonality of v. cholerae and parasitic infections were studied in detail. the detection rates for ascaris lumbricoides and giardia lamblia infection were more than for the hook ...200817594735
optimization and application of electrophoretic mobility analysis of human red blood cells to study their in vitro stability, interaction with polycations and proteolytic enzymes.electrophoretic light scattering method has been considered to determine both the mean and polydispersity of electrophoretic mobility of normal human red blood cells. the final goal of our study was to optimize an in vitro test allowing us to investigate the interaction of xenobiotics, in particular polyelectrolytes, with blood cells. the feasibility of our method has been evaluated based on the reproducibility of our technique to analyze the native electrophoretic mobility of human rbcs, as wel ...200817635023
prediction of epidemic cholera due to vibrio cholerae o1 in children younger than 10 years using climate data in bangladesh.to determine if a prediction of epidemic cholera using climate data can be made, we performed autoregression analysis using the data recorded in dhaka city, bangladesh over a 20-year period (1983-2002) comparing the number of children aged <10 years who were infected with vibrio cholerae o1 to the maximum and minimum temperatures and rainfall. we formulated a simple autoregression model that predicts the monthly number of patients using earlier climate variables. the monthly number of patients p ...200817346360
vibrio cholerae hemolysin is apoptogenic to peritoneal b-1a cells but its oligomer shepherd the cells for iga response.vibrio cholerae hemolysin (hlya) can exist as a monomer with hemolytic activity and an oligomer that agglutinates erythrocytes. biochemical differences accompanying the change in state of aggregation led us to weigh possible differences between the two forms from mucosal immunoregulation perspective. hlya oligomer-treated murine b-1a cells up-regulated tlr2 and involved the signaling molecules myd88, traf6 and nf-kappab. the cells subsequently expressed igm and iga. hlya monomer treatment althou ...200817570527
polish up on past pestilence and present pathogens.the cases presented here illustrate potential epidemic or pandemic events that once-silent pathogens portend. developing countries, where defenses are limited, are primary targets. of future concern are the developed countries that fail to use rigorous control measures established by the cdc, the who, and others to prevent the spread of infectious diseases. international travel has brought changes in demographics and a greater need for surveillance programs to control selective antibiotic resist ...200818630097
severe diarrhea caused by cholera toxin-producing vibrio cholerae serogroup o75 infections acquired in the southeastern united states.from 2003 through 2007, vibrio cholerae serogroup o75 strains possessing the cholera toxin gene were isolated from 6 patients with severe diarrhea, including 3 in georgia, 2 in alabama, and 1 in south carolina. these reports represent the first identification of v. cholerae o75 as a cause of illness in the united states. v. cholerae o75 was isolated from a water sample collected from a pond in louisiana in 2004. subsequently, 3 v. cholerae isolates from louisiana (2 from patients with diarrhea i ...200818781876
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