Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
an unusual cation-binding site and distinct domain-domain interactions distinguish class ii enolpyruvylshikimate-3-phosphate synthases.enolpyruvylshikimate-3-phosphate synthase (epsps) catalyzes a critical step in the biosynthesis of a number of aromatic metabolites. an essential prokaryotic enzyme and the molecular target of the herbicide glyphosate, epspss are the subject of both pharmaceutical and commercial interest. two epsps classes that exhibit low sequence homology, differing substrate/glyphosate affinities, and distinct cation activation properties have previously been described. here, we report structural studies of t ...201626813771
the epidemiology and antimicrobial resistance of cholera cases in iran during 2013.cholera is an endemic diarrheal disease in iran, caused by vibrio cholerae. the epidemiology, transmission route, environmental determinants and antimicrobial resistant pattern of cholera have been changed during recent years. in this study the epidemiology and antimicrobial resistance of cholera in iran during 2013 outbreak was investigated.201628210461
the replication initiator of the cholera pathogen's second chromosome shows structural similarity to plasmid initiators.the conserved dnaa-oric system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. in the cholera pathogen, vibrio cholerae, and in related species, secondary chromosome replication requires the rctb initiator protein. here, we show that rctb consists of four domains. the structure of its central two domains resembles that of several plasmid ...201628031373
whole-genome sequences of 26 vibrio cholerae isolates.the human pathogen vibrio cholerae employs several adaptive mechanisms for environmental persistence, including natural transformation and type vi secretion, creating a reservoir for the spread of disease. here, we report whole-genome sequences of 26 diverse v. cholerae isolates, significantly increasing the sequence diversity of publicly available v. cholerae genomes.201628007852
nitrosative stress response in vibrio cholerae: role of s-nitrosoglutathione reductase.vibrio cholerae, the causative agent of cholera, poses serious threats to humans worldwide. v. cholerae faces host inflammatory response and encounters nitrosative stress before establishing successful colonization. it is not clear how v. cholerae combats nitric oxide and reactive nitrogen species. in the present study, we used three clinical strains of v. cholerae and tested their nitrosative stress response pattern towards sodium nitroprusside (snp) and s-nitrosoglutathione (gsno). among them, ...201628000045
cholera rapid test with enrichment step has diagnostic performance equivalent to culture.cholera rapid diagnostic tests (rdt) could play a central role in outbreak detection and surveillance in low-resource settings, but their modest performance has hindered their broad adoption. the addition of an enrichment step may improve test specificity. we describe the results of a prospective diagnostic evaluation of the crystal vc rdt (span diagnostics, india) with enrichment step and of culture, each compared to polymerase chain reaction (pcr), during a cholera outbreak in south sudan. rdt ...201627992488
origins of pandemic vibrio cholerae from environmental gene pools.some microorganisms can transition from an environmental lifestyle to a pathogenic one(1-3). this ecological switch typically occurs through the acquisition of horizontally acquired virulence genes(4,5). however, the genomic features that must be present in a population before the acquisition of virulence genes and emergence of pathogenic clones remain unknown. we hypothesized that virulence adaptive polymorphisms (vaps) circulate in environmental populations and are required for this transition ...201627991885
ribavirin suppresses bacterial virulence by targeting lysr-type transcriptional regulators.targeting bacterial virulence mechanisms without compromising bacterial growth is a promising strategy to prevent drug resistance. lysr-type transcriptional regulators (lttrs) possess structural conservation across bacterial species and regulate virulence in numerous pathogens, making them attractive targets for antimicrobial agents. we targeted aphb, a vibrio cholerae lttr, which regulates the expression of genes encoding cholera toxin and toxin-co-regulated pilus for inhibitor designing. since ...201627991578
polymer-based oral rehydration solution for treating acute watery diarrhoea.acute diarrhoea is one of the main causes of morbidity and mortality among children in low-income countries. glucose-based oral rehydration solution (ors) helps replace fluid and prevent further dehydration from acute diarrhoea. since 2004, the world health organization (who) has recommended the osmolarity of less than 270 mosm/l (ors ≤ 270) versus greater than 310 mosm/l formulation (ors ≥ 310). polymer-based ors (for example, prepared using rice or wheat) slowly releases glucose and may be sup ...201627959472
haitian variant tcpa in vibrio cholerae o1 el tor strains in national capital region (india). 201627934812
comparison of antibody immobilization strategies in detection of vibrio cholerae by surface plasmon resonance.surface plasmon resonance immunosensor for the detection of bacterial cells was first reported in 1998 with high detection limit as much as 10(7 )cfu/ml. since then, many efforts have been made aiming to lower the detection limit and improve the sensitivity of detection. the aim of this study was to compare the effect of four most frequently used immobilization strategies, including direct physical adsorption (physisorption), covalent immobilization via self-assembled monolayer (sam) formation, ...201627923270
cross-protection against vibrio cholerae infection by monoclonal antibodies against vibrio vulnificus rtxa1/martxvv.gram-negative vibrio species secrete multifunctional autoprocessing repeats-in-toxin (martx) toxins associated with bacterial pathogenesis. here, the cross-reactivity and cross-protectivity of mabs against v. vulnificus rtxa1/martxvv was evaluated. passive administration of any of these mabs (21ra, 24ra, 46ra, 47ra and 50ra) provided strong protection against lethal v. cholerae infection. interestingly, 24ra and 46ra, which map to the cysteine protease domain of v. cholerae martxvc , inhibited c ...201627921342
role of non-coding regulatory rna in the virulence of human pathogenic vibrios.in recent decades, the identification of small non-coding rnas in bacteria has revealed an important regulatory mechanism of gene expression involved in the response to environmental signals and to the control of virulence. in the family vibrionaceae, which includes several human and animal pathogens, small non-coding rnas (srnas) are closely related to important processes including metabolism, quorum sensing, virulence, and fitness. studies conducted in silico and experiments using microarrays ...201628123382
effects of chromosomal deletion of the operon encoding the multiple resistance and ph-related antiporter in vibrio cholerae.to examine the possible physiological significance of mrp, a multi-subunit cation/proton antiporter from vibrio cholerae, a chromosomal deletion δmrp of v. cholerae was constructed and characterized. the resulting mutant showed a consistent early growth defect in lb broth that became more evident at elevated ph of the growth medium and increasing na+ or k+ loads. after 24 h incubation, these differences disappeared likely due to the concerted effort of other cation pumps in the mrp mutant. pheno ...201627902431
selective and efficient elimination of vibrio cholerae with a chemical modulator that targets glucose metabolism.vibrio cholerae, a gram-negative bacterium, is the causative agent of pandemic cholera. previous studies have shown that the survival of the seventh pandemic el tor biotype v. cholerae strain n16961 requires production of acetoin in a glucose-rich environment. the production of acetoin, a neutral fermentation end-product, allows v. cholerae to metabolize glucose without a ph drop, which is mediated by the production of organic acid. this finding suggests that inhibition of acetoin fermentation c ...201627900286
quorum regulated resistance of vibrio cholerae against environmental bacteriophages.predation by bacteriophages can significantly influence the population structure of bacterial communities. vibrio cholerae the causative agent of cholera epidemics interacts with numerous phages in the aquatic ecosystem, and in the intestine of cholera patients. seasonal epidemics of cholera reportedly collapse due to predation of the pathogen by phages. however, it is not clear how sufficient number of the bacteria survive to seed the environment in the subsequent epidemic season. we found that ...201627892495
phenotypic and antibiogram pattern of v. cholerae isolates from a tertiary care hospital in mumbai during 2004-2013: a retrospective cross-sectional study.cholera is a major gastroenteric disease with reports on fluctuation and resistance. hence, the objective is to determine the trend in seasonality, resistance pattern, prevalent biotypes, serotypes and phage types between 2004 and 2013 among vibrio cholerae isolates.201627888174
origins of the current seventh cholera pandemic.vibrio cholerae has caused seven cholera pandemics since 1817, imposing terror on much of the world, but bacterial strains are currently only available for the sixth and seventh pandemics. the el tor biotype seventh pandemic began in 1961 in indonesia, but did not originate directly from the classical biotype sixth-pandemic strain. previous studies focused mainly on the spread of the seventh pandemic after 1970. here, we analyze in unprecedented detail the origin, evolution, and transition to pa ...201627849586
a genomic island in vibrio cholerae with vpi-1 site-specific recombination characteristics contains crispr-cas and type vi secretion modules.cholera is a devastating diarrhoeal disease caused by certain strains of serogroup o1/o139 vibrio cholerae. mobile genetic elements such as genomic islands (gis) have been pivotal in the evolution of o1/o139 v. cholerae. perhaps the most important gi involved in cholera disease is the v. cholerae pathogenicity island 1 (vpi-1). this gi contains the toxin-coregulated pilus (tcp) gene cluster that is necessary for colonization of the human intestine as well as being the receptor for infection by t ...201627845364
antimicrobial susceptibility of autochthonous aquatic vibrio cholerae in haiti.we investigated the antimicrobial susceptibility of 50 environmental isolates of vibrio cholerae non-o1/non-o139 collected in surface waters in haiti in july 2012, during an active cholera outbreak. a panel of 16 antibiotics was tested on the isolates using the disk diffusion method and pcr detection of seven resistance-associated genes (stra/b, sul1/2, erma/b, and mefa). all isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, ciprofloxacin, norfloxacin, amikacin, and ...201627818656
characterization of the gluconate utilization system of vibrio cholerae with special reference to virulence modulation.orthologs search identified that the vibrio cholerae gluconate (gnt) utilization system minimally consisted of the entner-doudoroff (ed) pathway (edd and eda) and three other genes, namely gntu, gntk and gntr this system appeared unique by genomic organization of component genes into two operons transcribed in opposite directions. in silico analysis indicated gntu as an inner-membrane protein functioning for transport and gntk as a kinase with cytosolic localization that generates gnt6p, which i ...201627650573
transmission of infectious vibrio cholerae through drinking water among the household contacts of cholera patients (chobi7 trial).recurrent cholera causes significant morbidity and mortality among the growing population of dhaka, the capital city of bangladesh. previous studies have demonstrated that household contacts of cholera patients are at >100 times higher risk of cholera during the week after the presentation of the index patient. our prospective study investigated the mode of transmission of vibrio cholerae, the cause of cholera, in the households of cholera patients in dhaka city. out of the total 420 rectal swab ...201627803695
occurrence of vibrio parahaemolyticus, vibrio cholerae and vibrio vulnificus in the clam ruditapes philippinarum (adams & reeve, 1850) from emilia romagna and sardinia, italy.marine vibrios, vibrio parahaemolyticus, v. vulnificus and v. cholerae are responsible of the majority of food-borne human infections by consumption of bivalve shellfish. the aim of the present study was to ascertain the occurrence of these bacteria, and their potential pathogenicity, in the manila clam r. philippinarum from emilia romagna (er) and sardinia (sr) regions, italy. isolation was performed on chromagar(tm) vibrio with subculture on (thiosulfate-citrate-bile salts-sucrose) agar and m- ...201627800436
anoctamin 6 contributes to cl- secretion in accessory cholera enterotoxin (ace)-stimulated diarrhea: an essential role for phosphatidylinositol 4,5-bisphosphate (pip2) signaling in cholera.accessory cholera enterotoxin (ace) of vibrio cholerae has been shown to contribute to diarrhea. however, the signaling mechanism and specific type of cl(-) channel activated by ace are still unknown. we have shown here that the recombinant ace protein induced icl of apical plasma membrane, which was inhibited by classical cacc blockers. surprisingly, an ace-elicited rise of current was neither affected by ano1 (tmem16a)-specific inhibitor t16a(inh)-ao1(tao1) nor by the cystic fibrosis transmemb ...201627799301
a plant from the altiplano of northern chile senecio nutans, inhibits the vibrio cholerae pathogen.in the altiplano of northern chile the plant senecio nutans is habitually used as an infusion to relieve the effects of altitude sickness (locally known as "puna"). it is also used to alleviate the bronchitis, whooping cough, asthma, stomachache, tiredness and fever. the extreme conditions under which these plant grow and scientific data that shows the inhibiting potential of the essential oils of plants of the genus senecio represents great potential in the study of their application to control ...201627795930
nanocarriers from gras zein proteins to encapsulate hydrophobic actives.one factor limiting the expansion of nanomedicines has been the high cost of the materials and processes required for their production. we present a continuous, scalable, low cost nanoencapsulation process, flash nanoprecipitation (fnp) that enables the production of nanocarriers (ncs) with a narrow size distribution using zein corn proteins. zein is a low cost, gras protein (having the fda status of "generally regarded as safe") currently used in food applications, which acts as an effective en ...201627744703
the role of vibrio cholerae haemagglutinin protease (hap) in extra-intestinal infection.based on the diversity of surface o antigen vibrio cholerae can be classified into 206 serogroups. vibrio cholerae is the causative agent of cholera and extra intestinal infections like, septicemia, wound infection and haemorrhagic reactions. pathogenic factors of v. cholerae extra-intestinal infection are yet to be explored.201627790431
cholera cases cluster in time and space in matlab, bangladesh: implications for targeted preventive interventions.cholera remains a serious public health threat in asia, africa and in parts of the americas. three world health organization (who) pre-qualified oral cholera vaccines are now available but their supply is limited, so current supplies must be administered strategically. this requires an improved understanding of disease transmission and control strategies.201627789673
complete genome sequences of two marine vibrio cholerae strains isolated from the south coast of sweden.vibrio cholerae serogroups o1 and o139 are commonly associated with diarrhea, while non-o1-o139 strains may cause wound infections. here, we present the genome sequences of two v. cholerae strains isolated from blue mussels (mytilus edulis) collected in coastal waters of southern sweden.201627789632
adherence to intestinal cells promotes biofilm formation in vibrio cholerae.vibrio cholerae, the etiological agent of cholera, is known to form biofilms to persist in the environment. it is demonstrated here that even during infection, biofilm genes are upregulated, and microscopic observation indicated that biofilm formation is initiated almost immediately after adherence of v. cholerae to intestinal cells. about 7-fold upregulation of the biofilm regulatory gene vpst was observed within 30 minutes of adherence of v. cholerae to the intestinal cell line int 407, and a ...201627638940
vibrio cholerae laboratory infection of the adult house fly musca domestica.the present study was designed to test the hypothesis that house flies may be capable of specifically harbouring ingested vibrio cholerae in their digestive tracts. flies were continuously fed green fluorescent protein (gfp)-labelled, non-o1/non-o139 environmental strains of v. cholerae. bacterial burdens were quantitatively measured using plate counts and localization was directly observed using confocal microscopy. vibrio cholerae were present in the fly alimentary canal after just 4 h, and re ...201627444689
non-toxigenic environmental vibrio cholerae o1 strain from haiti provides evidence of pre-pandemic cholera in hispaniola.vibrio cholerae is ubiquitous in aquatic environments, with environmental toxigenic v. cholerae o1 strains serving as a source for recurrent cholera epidemics and pandemic disease. however, a number of questions remain about long-term survival and evolution of v. cholerae strains within these aquatic environmental reservoirs. through monitoring of the haitian aquatic environment following the 2010 cholera epidemic, we isolated two novel non-toxigenic (ctxa/b-negative) vibrio cholerae o1. these t ...201627786291
a monoclonal antibody that targets the conserved core/lipid a region of lipopolysaccharide affects motility and reduces intestinal colonization of both classical and el tor vibrio cholerae biotypes.vibrio cholerae is the causative agent of cholera, an acute diarrheal disease that remains endemic in many parts of the world. the mechanisms underlying immunity to cholera remain poorly defined, though it is increasingly clear that protection is associated with antibodies against lipopolysaccharide (lps). here we report that zac-3, a monoclonal antibody against the core/lipid a region of v. cholerae lps is a potent inhibitor of v. cholerae flagellum-based motility in viscous and liquid environm ...201627773473
in silico identification of outer membrane protein (omp) and subunit vaccine design against pathogenic vibrio cholerae.virulence-related outer membrane proteins (omps) are expressed in bacteria (gram-negative) such as v. cholerae and are vital to bacterial invasion in to eukaryotic cell and survival within macrophages that could be best candidate for development of vaccine against v. cholerae. applying in silico approaches, the 3-d model of the omp was developed using swiss model server and validated byprosa and procheck web server. the continuous stretch of amino acid sequences 26mer: rtrsnsglltwgdkqtitleygdpal ...201627769003
travel-associated vibrio cholerae o1 el tor, russia. 201627767910
effectiveness of one dose of oral cholera vaccine in response to an outbreak: a case-cohort study.oral cholera vaccines represent a new effective tool to fight cholera and are licensed as two-dose regimens with 2-4 weeks between doses. evidence from previous studies suggests that a single dose of oral cholera vaccine might provide substantial direct protection against cholera. during a cholera outbreak in may, 2015, in juba, south sudan, the ministry of health, médecins sans frontières, and partners engaged in the first field deployment of a single dose of oral cholera vaccine to enhance the ...201627765293
a five-year study on the epidemiological approaches to cholera in iran.cholera is considered a key indicator of social development but still is reported in various cities of iran. the present study aimed to analyze the available information regarding cholera outbreaks since 2010 in iran.201627757199
toxigenic vibrio cholerae o1 in vegetables and fish raised in wastewater irrigated fields and stabilization ponds during a non-cholera outbreak period in morogoro, tanzania: an environmental health study.cholera, one of the world's deadliest infectious diseases, remains rampant and frequent in tanzania and thus hinders existing control measures. the present study was undertaken to evaluate the occurrence of toxigenic vibrio cholerae o1 in wastewater, fish and vegetables during a non-outbreak period in morogoro, tanzania.201627756420
no-go zones for mariner transposition.the property of transposons to randomly insert into target dna has long been exploited for generalized mutagenesis and forward genetic screens. newer applications that monitor the relative abundance of each transposon insertion in large libraries of mutants can be used to evaluate the roles in cellular fitness of all genes of an organism, provided that transposition is in fact random across all genes. in a recent article, kimura and colleagues identified an important exception to the latter assu ...201627729512
cholera.cholera is an acute disease of the gastrointestinal tract caused by vibrio cholerae. cholera was localized in asia until 1817, when a first pandemic spread from india to several other regions of the world. after this appearance, six additional major pandemics occurred during the 19th and 20th centuries, the latest of which originated in indonesia in the 1960s and is still ongoing. in 1854, a cholera outbreak in soho, london, was investigated by the english physician john snow (1813 to 1858). he ...201627726771
major shift of toxigenic v. cholerae o1 from ogawa to inaba serotype isolated from clinical and environmental samples in haiti.in october of 2010, an outbreak of cholera was confirmed in haiti for the first time in more than a century. a single clone of toxigenic vibrio cholerae o1 biotype el tor serotype ogawa strain was implicated as the cause. five years after the onset of cholera, in october, 2015, we have discovered a major switch (ranging from 7 to 100%) from ogawa serotype to inaba serotype. furthermore, using wbet gene sequencing and comparative sequence analysis, we now demonstrate that, among 2013 and 2015 ina ...201627716803
quantification of vibrio species in oysters from the gulf of mexico with two procedures based on mpn and pcr.oysters can accumulate potentially pathogenic water bacteria. the objective of this study was to compare two procedures to quantify vibrio species present in oysters to determine the most sensitive method. we analyzed oyster samples from the gulf of mexico, commercialized in mexico city. the samples were inoculated in tubes with alkaline peptone water (apw), based on three tubes and four dilutions (10(-1) to 10(-4)). from these tubes, the first quantification of vibrio species was performed (mos ...201627709461
retrospective analysis of serotype switching of vibrio cholerae o1 in a cholera endemic region shows it is a non-random process.genomic data generated from clinical vibrio cholerae o1 isolates collected over a five year period in an area of kolkata, india with seasonal cholera outbreaks allowed a detailed genetic analysis of serotype switching that occurred from ogawa to inaba and back to ogawa. the change from ogawa to inaba resulted from mutational disruption of the methyltransferase encoded by the wbet gene. re-emergence of the ogawa serotype was found to result either from expansion of an already existing ogawa clade ...201627706170
chlorination of household drinking water among cholera patients' households to prevent transmission of toxigenic vibrio cholerae in dhaka, bangladesh: chobi7 trial.household members of cholera patients are at a 100 times higher risk of cholera infections than the general population because of shared contaminated drinking water sources and secondary transmission through poor household hygiene practices. in this study, we investigated the bactericidal concentration of free chlorine required to inactivate vibrio cholerae in household drinking water in dhaka, bangladesh. in laboratory experiments, we found that the concentrations of free chlorine required to i ...201627698273
intrinsic gtpase activity of a ribosomal maturation protein cgta is associated with its inter-domain movement: insights from md simulations and biochemical studies.cgta is an essential ribosome associated gtpase protein of bacteria. it has three domains, viz., obg, gtpase, and c-terminal domain. it is a multifunctional protein and it is being considered as a potential drug target against bacterial infections. despite the importance, cgta's action mechanisms are not well known which warrants further study. towards that goal, we are pursuing biochemical and computational studies in vibrio cholerae cgta (cgtavc). biochemically we found that a single amino aci ...201627677930
role of a sensor histidine kinase chis of vibrio cholerae in pathogenesis.vibrio cholera survival in an aquatic environment depends on chitin utilization pathway that requires two factors, chitin binding protein and chitinases. the chitinases and the chitin utilization pathway are regulated by a two-component sensor histidine kinase chis in v. cholerae. in recent studies these two factors are also shown to be involved in v. cholerae pathogenesis. however, the role played by their upstream regulator chis in pathogenesis is yet to be known. in this study, we investigate ...201627670078
thiol-based switch mechanism of virulence regulator aphb modulates oxidative stress response in vibrio cholerae.bacterial pathogens display versatile gene expression to adapt to changing surroundings. for example, vibrio cholerae, the causative agent of cholera, utilizes distinct genetic programs to combat reactive oxygen species (ros) in aquatic environments or during host infection. we previously reported that the virulence activator aphb in v. cholerae is involved in ros resistance. here by performing a genetic screen, we show that aphb represses ros resistance gene ohra, which is also repressed by ano ...201627625149
total synthesis of the complete protective antigen of vibrio cholerae o139.the first chemical synthesis of the complete protective o-antigen of a human-disease-causing pathogenic bacterium is described. the synthesis involved a protecting-group strategy that facilitated the regioselectivity of the key transformations, stereoselective glycosylation reactions, and enabled the one-step global deprotection of the completely assembled, fully protected, phosphorylated hexasaccharide by hydrogenation/hydrogenolysis. the final amino-group-functionalized, linker-equipped antige ...201627623688
genetic studies of vibrio cholerae in south west cameroon-a phylogenetic analysis of isolates from the 2010-2011 epidemic.during the cholera outbreak from 2010 to 2011 in cameroon, 33,192 cases with 1,440 deaths (case fatality ratio 4.34%) were reported to the world health organization. of these, the south west region reported 3,120 clinical cases. this region is in the equatorial monsoon climatic subzone of cameroon, close to the coast, raising questions as to whether cases were linked with development of environmental reservoirs.201627617169
redox pathway sensing bile salts activates virulence gene expression in vibrio cholerae.vibrio cholerae, the causative agent of the severe diarrheal disease cholera, has evolved signal transduction systems to control co-ordinately the expression of virulence determinants. it was previously shown that the presence of the bile salts glycocholate and taurocholate in the small intestine causes dimerization of the transmembrane transcription factor tcpp by inducing intermolecular disulphide bonds in the tcpp periplasmic domain. in this study, they further investigated the mechanism of h ...201627610607
sialylation transmogrifies human breast and pancreatic cancer cells into 3d multicellular tumor spheroids using cyclic rgd-peptide induced self-assembly.multicellular tumor spheroids (mts) have been at the forefront of cancer research, designed to mimic tumor-like developmental patterns in vitro. tumor growth in vivo is highly influenced by aberrant cell surface-specific sialoglycan structures on glycoproteins. aberrant sialoglycan patterns that facilitate mts formation are not well defined. matrix-free spheroids from breast mcf-7 and pancreatic panc1 cancer cell lines and their respective tamoxifen (tmx) and gemcitabine (gem) resistant variants ...201627608845
intestinal ameliorative effects of traditional ogi-tutu, vernonia amygdalina and psidium guajava in mice infected with vibrio cholera.cholera, a severe acute watery diarrhea caused by vibrio cholerae is endemic in nigeria with most cases occurring in the rural areas. in south west nigeria, some individuals resort to alternative treatments such as ogi-tutu, psidium guajava and vernonia amygdalina during infections. the effectiveness of these alternatives in the prevention and treatment of v. cholerae infection requires experimental investigation.201627605980
a rare case of necrotizing fasciitis caused by vibrio cholerae o8 in an immunocompetent patient.we report a case of necrotizing fasciitis of the leg caused by vibrio cholerae o8 in a 63-year-old immunocompetent man after he had been fishing in a lake on a croatian island. the strain was cytotoxic, invasive and adhesive and contained a fragment of the gene for el tor-like hemolysin (el tor hlya). after surgical and antibiotic treatment, the patient fully recovered.201627604649
1.65 å resolution structure of the arac-family transcriptional activator toxt from vibrio cholerae.toxt is an arac-family transcriptional activator protein that controls the expression of key virulence factors in vibrio cholerae, the causative agent of cholera. toxt directly activates the expression of the genes that encode the toxin-coregulated pilus and cholera toxin, and also positively auto-regulates its own expression from the tcp promoter. the crystal structure of toxt has previously been solved at 1.9 å resolution (pdb entry 3gbg). in this study, a crystal structure of toxt at 1.65 å r ...201627599865
development of a multiplex pcr for discrimination of the tlc:rs1:ctx array of vibrio cholerae wave 3 el tor strains.vibrio cholerae o1 serogroup wave 3 el tor strains are presently prevalent worldwide. the wave 3 el tor strains contain a tlc:rs1:ctx array on chromosome 1, and no element is integrated on chromosome 2. a multiplex pcr optimized to identify the tlc:rs1:ctx array of wave 3 strains has been developed in this study. by using eight primers, the multiplex pcr can identify the characteristic ctx and rs1 array of wave 3 strains from various arrays of strains belonging to other waves. the four amplified ...201627586526
measuring in vitro atpase activity for enzymatic characterization.adenosine triphosphate-hydrolyzing enzymes, or atpases, play a critical role in a diverse array of cellular functions. these dynamic proteins can generate energy for mechanical work, such as protein trafficking and degradation, solute transport, and cellular movements. the protocol described here is a basic assay for measuring the in vitro activity of purified atpases for functional characterization. proteins hydrolyze atp in a reaction that results in inorganic phosphate release, and the amount ...201627584824
the nucleoid binding protein h-ns biases genome-wide transposon insertion landscapes.transposon insertion sequencing (tis; also known as tnseq) is a potent approach commonly used to comprehensively define the genetic loci that contribute to bacterial fitness in diverse environments. a key presumption underlying analyses of tis datasets is that loci with a low frequency of transposon insertions contribute to fitness. however, it is not known whether factors such as nucleoid binding proteins can alter the frequency of transposon insertion and thus whether tis output may systematic ...201627578758
chemotaxis cluster 1 proteins form cytoplasmic arrays in vibrio cholerae and are stabilized by a double signaling domain receptor dosm.nearly all motile bacterial cells use a highly sensitive and adaptable sensory system to detect changes in nutrient concentrations in the environment and guide their movements toward attractants and away from repellents. the best-studied bacterial chemoreceptor arrays are membrane-bound. many motile bacteria contain one or more additional, sometimes purely cytoplasmic, chemoreceptor systems. vibrio cholerae contains three chemotaxis clusters (i, ii, and iii). here, using electron cryotomography, ...201627573843
characterization of vibrio cholerae strains isolated from the nigerian cholera outbreak in 2010.we examined clinical samples from nigerian patients with acute watery diarrhea for vibrio cholerae during the 2010 cholera outbreak. a total of 109 suspected isolates were characterized, but only 57 v. cholerae strains could be confirmed using multiplex real-time pcr as well as rpob sequencing and typed as v. cholerae o:1 ogawa biotype el tor. this finding highlighted the need for accurate diagnosis of cholera in epidemic countries to implement life-saving interventions.201627487957
effects of tcpb mutations on biogenesis and function of the toxin-coregulated pilus, the type ivb pilus of vibrio cholerae.vibrio cholerae is the etiological agent of the acute intestinal disorder cholera. the toxin-coregulated pilus (tcp), a type ivb pilus, is an essential virulence factor of v. cholerae recent work has shown that tcpb is a large minor pilin encoded within the tcp operon. tcpb contributes to efficient pilus formation and is essential for all tcp functions. here, we have initiated a detailed targeted mutagenesis approach to further characterize this salient tcp component. we have identified (thus fa ...201627481929
comparative genomic analysis of two isolates of vibrio cholerae o1 ogawa el tor isolated during outbreak in mariupol in 2011.cholera is a water-borne, severe enteric infection essentially caused by toxigenic strains of vibrio cholera o1 and o139 serogroups. an outbreak of cholera was registered during may-july 2011 in mariupol, ukraine, with 33 cholera cases and 25 carriers of cholera. following this outbreak, the toxigenic strain of v. cholerae 2011el-301 was isolated from seawater in the recreation area of taganrog city on the territory of russia. the aim of our study was to understand genomic features of mariupol i ...201627480918
understanding, monitoring, and controlling biofilm growth in drinking water distribution systems.in drinking water distribution systems (dwds), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (eps) protecting the biomass from environmental and shear stresses. biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. this article crit ...201627479445
unique clones of vibrio cholerae o1 el tor with haitian type ctxb allele implicated in the recent cholera epidemics from nigeria, africa.the antimicrobial susceptibility patterns and genetic characteristics of vibrio cholerae o1, which is responsible for several cholera epidemics in nigeria, are not reported in detail since 2007. in this study, we screened v. cholerae o1 el tor biotype isolates from cholera cases and water samples from different states to investigate their phenotypic and genetic attributes with special reference to their clonality.201627479360
multi-scale molecular dynamics study of cholera pentamer binding to a gm1-phospholipid membrane.the ab5 type toxin produced by the vibrio cholerae bacterium is the causative agent of the cholera disease. the cholera toxin (ct) has been shown to bind specifically to gm1 glycolipids on the membrane surface. this binding of ct to the membrane is the initial step in its endocytosis and has been postulated to cause significant disruption to the membrane structure. in this work, we have carried out a combination of coarse-grain and atomistic simulations to study the binding of ct to a membrane m ...201627474868
sequences of a co-existing sxt element, a chromosomal integron (ci) and an inca/c plasmid and their roles in multidrug resistance in a vibrio cholerae o1 el tor strain.the ongoing seventh cholera pandemic is attributed to vibrio cholerae o1 el tor biotype strains. although antibiotic therapy ameliorates symptoms in patients and reduces pathogen transfer to the environment, multidrug resistance remains a major clinical threat. an o1 el tor strain isolated from a patient in 1998 was intermediate or resistant to 13 antibiotics and could potentially produce extended-spectrum β-lactamase (esbl), which is very rare in o1 strains. using genome sequencing, three relev ...201627470490
isolation and identification of vibrio cholerae and vibrio parahaemolyticus from prawn (penaeus monodon) seafood: preservation strategies.bacterial diseases are one of the major problems which affects the production, development and expansion of aqua culture. vibrio sp. are widespread in marine and estuarine environments. the several pathogenic species are commonly associated with outbreaks of vibrio species and it is mainly associated with food poisonings. in this research, the occurrence of vibrio sp. was studied by the isolation and it is confirmed by the biochemical methods. the growth rate was studied by changing the differen ...201627457973
molecular epidemiology of vibrio cholerae o1 in northern vietnam (2007-2009), using multilocus variable-number tandem repeat analysis.cholera is an infectious disease of major concern in vietnam and other asian countries. in 2009, there was a large outbreak of cholera in northern vietnam. to investigate relationships among isolates of the causative pathogen vibrio cholerae in this region since 2007, we carried out a multilocus variable-number tandem repeat analysis (mlva) of 170 isolates collected between 2007 and 2009. a total of 24 mlva types were identified using seven loci. five clones (1-5) were identified using five loci ...201627452304
chemical synthesis of the galacturonic acid containing pentasaccharide antigen of the o-specific polysaccharide of vibrio cholerae o139 and its five fragments.three pentasaccharides, two tetrasaccharides, and a trisaccharide fragment of the o-specific antigen of vibrio cholerae o139 were synthesized by applying 1 + 1, 2 + 1, 3 + 1, and 4 + 1 coupling strategies. the most challenging tasks involved were the synthesis of the 1,2-cis-glycosidic linkage between galactose and the linker (spacer) molecule and final purification of the target multicharged substances. difficulties with final deprotection by hydrogenation/hydrogenolysis caused by the presence ...201627452084
the complete genomic analysis of an imported vibrio cholerae from myanmar in southwest china.we sequenced and analyzed an imported vibrio cholerae from mynamar in 2011 by using whole genome sequencing method in yunnan province, southwest china. other 3 isolates of v. cholerae in yunnan were also sequenced for comparing purpose. illumina hiseq2500 was used and the sequencing results were assembled and annotated. the comparative genomic analysis was also performed with 101 reference strains from china and abroad. the results showed the imported v. cholerae (yn2011004) had two chromosomes ...201627448952
genome sequence of the k139-like phage vcp032 originating from the vibrio cholerae o1 el tor ogawa serotype.vibrio cholerae is the cause of large cholera outbreaks, especially in endemic regions with high poverty and inadequate sanitation. here, we announce the complete genome sequence of the virulence-associated broad host range v. cholerae phage vcp032, including a brief summary of its genotypic and phenotypic features.201627445393
development of an immunosensor using oriented immobilized anti-ompw for sensitive detection of vibrio cholerae by surface plasmon resonance.the first spr sensor for detection of bacteria was reported in 1998 with high detection limit as much as 10(7)cfu/ml. since then, a lot of effort has been made to lower detection limit and increase sensitivity of detection mainly by using of different assay formats, immobilization strategies, suitable antibodies, minimizing non-specific adsorption and improving the quality of spr devices. the aim of this paper is to introduce the potential of an antibody against recombinant outer membrane protei ...201627442077
hybridoma as a specific, sensitive, and ready to use sensing element: a rapid fluorescence assay for detection of vibrio cholerae o1.over the last decade, isolation and purification of monoclonal antibodies, for diagnostic analysis, have been carried out using the hybridoma expression system. the present study describes a novel example of a detection system using hybridoma cells containing antibody against o1 antigen directly for v. cholerae diagnosis, which is a major health problem in many parts of the world, especially in developing countries. this method has advantages such as simplicity, ease of process, and it does not ...201627438715
(1)h, (15)n and (13)c resonance assignments of the c-terminal domain of vibrio cholerae tola protein.vibrio cholerae is the bacterial causative agent of the human disease cholera. non-pathogenic bacterium can be converted to pathogenic following infection by a filamentous phage, ctxφ, that carries the cholera toxin encoding genes. a crucial step during phage infection requires a direct interaction between the ctxφ minor coat protein (piii(ctx)) and the c-terminal domain of v. cholerae tola protein (tolaiiivc). in order to get a better understanding of tola function during the infection process, ...201627436120
survival of vibrio cholerae o1 on fomites.it is well established that the contamination sources of cholera causing bacteria, vibrio cholerae, are water and food, but little is known about the transmission role of the fomites (surfaces that can carry pathogens) commonly used in households. in the absence of appropriate nutrients or growth conditions on fomites, bacteria have been known to assume a viable but non-culturable (vbnc) state after a given period of time. to investigate whether and when v. cholerae o1 assumes such a state, this ...201627430513
conformational flexibility and dynamics of the internal loop and helical regions of the kink-turn motif in the glycine riboswitch by site-directed spin-labeling.site-directed spin-labeling (sdsl) electron paramagnetic resonance (epr) spectroscopy provides a means for a solution state description of site-specific dynamics and flexibility of large rnas, facilitating our understanding of the effects of environmental conditions such as ligands and ions on rna structure and dynamics. here, the utility and capability of epr line shape analysis and distance measurements to monitor and describe site-specific changes in the conformational dynamics of internal lo ...201627427937
are natural reservoirs important for cholera surveillance? the case of an outbreak in a brazilian estuary.paranaguá bay is one of the largest estuarine systems on the southern brazilian coast. the only recorded cholera outbreak in this region since the early 20th century occurred in 1999 and resulted in 467 cases and at least three reported deaths in a population of approx. 150 000 people. this short communication reports historical, unpublished data related to that outbreak. water, zooplankton and bivalve samples were collected and evaluated using direct fluorescence assay to determine whether vibr ...201627416521
comparison of dot-elisa and standard-elisa for detection of the vibrio cholerae toxin in culture supernatants of bacteria isolated from human and environmental samples.a comparison of dot-elisa and standard-elisa was made for detection of vibrio cholerae toxin in culture supernatants of bacteria isolated from human and environmental samples. a total of 293 supernatants were tested in a double blind assay. a correlation of 100 % was obtained between both techniques. the cholera toxin was found in 20 inaba and 3 ogawa strains. positive samples were from seafood (17 samples), potable water (1 sample) and sewage (5 samples). the dot-elisa was useful as the standar ...201627407304
role of indole production on virulence of vibrio cholerae using galleria mellonella larvae model.cell to cell communication facilitated by chemical signals plays crucial roles in regulating various cellular functions in bacteria. indole, one such signaling molecule has been demonstrated to control various bacterial phenotypes such as biofilm formation and virulence in diverse bacteria including vibrio cholerae. the present study explores some key factors involved in indole production and the subsequent pathogenesis of v. cholerae. indole production was higher at 37 °c than at 30 °c, althoug ...201627407302
mechanisms underlying the immune response generated by an oral vibrio cholerae vaccine.mechanistic details underlying the resulting protective immune response generated by mucosal vaccines remain largely unknown. we investigated the involvement of toll-like receptor signaling in the induction of humoral immune responses following oral immunization with dukoral, comparing wild type mice with tlr-2-, tlr-4-, myd88- and trif-deficient mice. although all groups generated similar levels of igg antibodies, the proliferation of cd4+ t-cells in response to v. cholerae was shown to be medi ...201627384558
a small number of phylogenetically distinct clonal complexes dominate a coastal vibrio cholerae population.vibrio cholerae is a ubiquitous aquatic microbe in temperate and tropical coastal areas. it is a diverse species, with many isolates that are harmless to humans, while others are highly pathogenic. most notable among them are strains belonging to the pandemic o1/o139 serogroup lineage, which contains the causative agents of cholera. the environmental selective regimes that led to this diversity are key to understanding how pathogens evolve in environmental reservoirs. a local population of v. ch ...201627371587
heme-independent redox sensing by the heme-nitric oxide/oxygen-binding protein (h-nox) from vibrio cholerae.heme nitric oxide/oxygen (h-nox)-binding proteins act as nitric oxide (no) sensors among various bacterial species. in several cases, they act to mediate communal behavior such as biofilm formation, quorum sensing, and motility by influencing the activity of downstream signaling proteins such as histidine kinases (hiska) in a no-dependent manner. an h-nox/hiska regulatory circuit was recently identified in vibrio cholerae, and the h-nox protein has been spectroscopically characterized. however, ...201627358409
aaa+ proteases and their role in distinct stages along the vibrio cholerae lifecycle.the facultative human pathogen vibrio cholerae has to adapt to different environmental conditions along its lifecycle by means of transcriptional, translational and post-translational regulation. this study provides a first comprehensive analysis regarding the contribution of the cytoplasmic aaa+ proteases lon, clpp and hslv to distinct features of v. cholerae behaviour, including biofilm formation, motility, cholera toxin expression and colonization fitness in the mouse model. while absence of ...201627345492
structural and functional evidence indicates selective oxygen signaling in caldanaerobacter subterraneus h-nox.acute and specific sensing of diatomic gas molecules is an essential facet of biological signaling. heme nitric oxide/oxygen binding (h-nox) proteins are a family of gas sensors found in diverse classes of bacteria and eukaryotes. the most commonly characterized bacterial h-nox domains are from facultative anaerobes and are activated through a conformational change caused by formation of a 5-coordinate fe(ii)-no complex. members of this h-nox subfamily do not bind o2 and therefore can selectivel ...201627328180
the na+-translocating nadh:quinone oxidoreductase enhances oxidative stress in the cytoplasm of vibrio cholerae.we searched for a source of reactive oxygen species (ros) in the cytoplasm of the human pathogen vibrio cholerae and addressed the mechanism of ros formation using the dye 2',7'-dichlorofluorescein diacetate (dcfh-da) in respiring cells. by comparing v. cholerae strains with or without active na(+)-translocating nadh:quinone oxidoreductase (na(+)-nqr), this respiratory sodium ion redox pump was identified as a producer of ros in vivo the amount of cytoplasmic ros detected in v. cholerae cells pr ...201627325677
vibrio cholerae gbpa elicits necrotic cell death in intestinal cells.vibrio choleraen-acetylglucosamine-binding protein gbpa is a secretory protein that facilitates the initial adherence of bacteria in the human intestine. until now, considerable progress in the characterization of gbpa has been done, yet little is known about its role in host response. our present studies demonstrated that gbpa at the amount secreted in the intestine resulted in decreased cell viability, altered cell morphology, disruption of cell membrane integrity and damage of cellular dna in ...201627324251
genetic relatedness of selected clinical vibrio cholerae o139 isolates from the southern coastal area of china over a 20-year period.vibrio cholerae o139 emerged as a causative agent of epidemic cholera in 1992 in india and bangladesh, and was subsequently reported in china in 1993. the genetic relatedness and molecular characteristics of v. cholerae o139 in guangdong province, located in the southern coastal area of china, remains undetermined. in this study, we investigated 136 clinical v. cholerae o139 isolates from 1993 to 2013 in guangdong. by conventional pcr, 123 (90·4%) isolates were positive for ctxb, ace and zot. se ...201627305977
antibacterial and antiviral effectiveness of two household water treatment devices that use monobrominated hydantoinylated polystyrene.many different household water treatment (hwt) methods have been researched and promoted to mitigate the serious burden of diarrheal disease in developing countries. however, hwt methods using bromine have not been extensively evaluated. two gravity-fed hwt devices (aquasure™ and waterbird™) were used to test the antimicrobial effectiveness of halopure(®) br beads (monobrominated hydantoinylated polystyrene) that deliver bromine. as water flows over the beads, reactive bromine species are eluted ...201627959873
isolation, identification, and evaluation of novel probiotic strains isolated from feces of breast-fed infants.to isolate, identify, and evaluate the probiotic properties of lactic acid bacteria (lab) isolated from the feces of breast-fed infants.201626817236
clinical features of human immunodeficiency virus-infected patients presenting with cholera in port-au-prince, haiti.human immunodeficiency virus (hiv) infection has been postulated to alter the natural history of cholera, including increased susceptibility to infection, severity of illness, and chronic carriage of vibrio cholerae haiti has a generalized hiv epidemic with an adult hiv prevalence of 1.9% and recently suffered a cholera epidemic. we conducted a prospective study at the cholera treatment center (ctc) of gheskio in haiti to characterize the coinfection. adults admitted at the ctc for acute diarrhe ...201627549637
mucosal vaccination for prevention of hiv infection and aids.most of hiv infections occur via the genital tract or the rectum and hiv replicates at high levels in lymphoid organs and intestinal mucosa, likely requiring a more diversified immunity than pathogens restricted to a single mucosal site, such as the gastrointestinal tract for vibrio cholera, or the respiratory airways for the influenza virus.201626957199
"non-toxic" proteins of the botulinum toxin complex exert in-vivo toxicity.the botulinum neurotoxin (bont) causes muscle paralysis and is the most potent toxin in nature. bont is associated with a complex of auxiliary "non-toxic" proteins, which constitute a large-sized toxin complex (l-tc). however, here we report that the "non-toxic" complex of serotype d botulinum l-tc, when administered to rats, exerts in-vivo toxicity on small-intestinal villi. moreover, serotype c and d of the "non-toxic" complex, but not bont, induced vacuole-formation in a rat intestinal epithe ...201627507612
low prevalence of vibrio cholerae o1 versus moderate prevalence of intestinal parasites in food-handlers working with health care personnel in haiti.food-handlers with poor personal hygiene working in food-service establishments could be potential sources of infection due to pathogenic organisms. in may 2011, a cross-sectional study was undertaken to determine the prevalence of bacteria and intestinal parasites among food-handlers working with cuban health personnel in haiti. stool specimens were collected from 56 food-handlers and samples were examined using standard procedures. of the food handlers, 26.8% had one bacterial or intestinal pa ...201627077312
synthesis and biological evaluation of 5,7-dihydroxyflavanone derivatives as antimicrobial agents.a series of 5,7-dihydroxyflavanone derivatives were efficiently synthesized. their antimicrobial efficacy on gram-negative, gram-positive bacteria and yeast were evaluated. among these compounds, most of the halogenated derivatives exhibited the best antimicrobial activity against gram-positive bacteria, the yeast saccharomyces cerevisiae, and the gram-negative bacterium vibrio cholerae. the cytotoxicities of these compounds were low as evaluated on hepg2 cells using a cell viability assay. this ...201627210435
characterization of prohibitin 1 as a host partner of vibrio vulnificus rtxa1 toxin.rtxa1 toxin, which results in cytoskeletal rearrangement, contact cytotoxicity, hemolysis, tissue invasion, and lethality in mice, is the most potent cytotoxic virulence factor of vibrio vulnificus. bioinformatics analysis of rtxa1 predicted 4 functional domains that presumably performed discrete functions during host cell killing. v. vulnificus rtxa1 has a unique domain designated as rtxa1-d2, corresponding to amino acids 1951-2574, which is absent in vibrio cholerae multifunctional-autoprocess ...201626136468
the unusual redox properties of c-type oxidases.cytochrome cbb3 (also known as c-type) oxidases belong to the family of heme-copper terminal oxidases which couple at the end of the respiratory chain the reduction of molecular oxygen into water and the pumping of protons across the membrane. they are expressed most often at low pressure of o2 and they exhibit a low homology of sequence with the cytochrome aa3 (a-type) oxidases found in mitochondria. their binuclear active site comprises a high-spin heme b3 associated with a cub center. the pro ...201627664317
biofilm formation and detachment in gram-negative pathogens is modulated by select bile acids.biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. however, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we ...201626992172
vibrio cholerae hemagglutinin(ha)/protease: an extracellular metalloprotease with multiple pathogenic activities.vibrio cholerae of serogroup o1 and o139, the etiological agent of the diarrheal disease cholera, expresses the extracellular zn-dependent metalloprotease hemagglutinin (ha)/protease also reported as vibriolysin. this enzyme is also produced by non-o1/o139 (non-cholera) strains that cause mild, sporadic illness (i.e. gastroenteritis, wound or ear infections). orthologs of ha/protease are present in other members of the vibrionaceae family pathogenic to humans and fish. ha/protease belongs to the ...201626952544
species-dependent hydrodynamics of flagellum-tethered bacteria in early biofilm development.monotrichous bacteria on surfaces exhibit complex spinning movements. such spinning motility is often a part of the surface detachment launch sequence of these cells. to understand the impact of spinning motility on bacterial surface interactions, we develop a hydrodynamic model of a surface-bound bacterium, which reproduces behaviours that we observe in pseudomonas aeruginosa, shewanella oneidensis and vibrio cholerae, and provides a detailed dictionary for connecting observed spinning behaviou ...201626864892
genetic control of bacterial biofilms.nearly all bacterial species, including pathogens, have the ability to form biofilms. biofilms are defined as structured ecosystems in which microbes are attached to surfaces and embedded in a matrix composed of polysaccharides, edna, and proteins, and their development is a multistep process. bacterial biofilms constitute a large medical problem due to their extremely high resistance to various types of therapeutics, including conventional antibiotics. several environmental and genetic signals ...201626294280
characterization of mdaφ, a temperate filamentous bacteriophage of neisseria meningitidis.the mechanism by which neisseria meningitidis becomes invasive is not well understood. comparative genomics identified the presence of an 8 kb island in strains belonging to invasive clonal complexes. this island was designated mda for meningococcal disease associated. mda is highly conserved among meningococcal isolates and its analysis revealed a genomic organization similar to that of a filamentous prophage such as ctxφ of vibrio cholerae. subsequent molecular investigations showed that the m ...201626602366
Refresh
firstprev
...231232233234235236237238239240...
nextlast
Displaying items 23901 - 24000 of 24874