Publications

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[n-acetyl-β-d-glucosaminidase of vibrio cholerae].study n-acetyl-β-d-glucosaminidase (chitobiase) (ec 3.2.1.30) in strains of vibrio cholerae of o1/non-o1 serogroups of various origin, that is a component of chitinolytic complex taking into account object of isolation and epidemiologic significance of strains.201627228670
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
local and global consequences of flow on bacterial quorum sensing.bacteria use a chemical communication process called quorum sensing (qs) to control collective behaviours such as pathogenesis and biofilm formation(1,2). qs relies on the production, release and group-wide detection of signal molecules called autoinducers. to date, studies of bacterial pathogenesis in well-mixed cultures have revealed virulence factors and the regulatory circuits controlling them, including the overarching role of qs(3). although flow is ubiquitous to nearly all living systems( ...201627571752
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
anticancer and antibacterial secondary metabolites from the endophytic fungus penicillium sp. cam64 against multi-drug resistant gram-negative bacteria.the emergence of multiple-drug resistance bacteria has become a major threat and thus calls for an urgent need to search for new effective and safe anti-bacterial agents.201627917206
antibacterial and cytotoxic cytochalasins from the endophytic fungus phomopsis sp. harbored in garcinia kola (heckel) nut.the continuous emergence of multidrug-resistant (mdr) bacteria drastically reduced the efficacy of our antibiotic armory and consequently, increased the frequency of therapeutic failure. the search for bioactive constituents from endophytic fungi against mdr bacteria became a necessity for alternative and promising strategies, and for the development of novel therapeutic solutions. we report here the isolation and structure elucidation of antibacterial and cytotoxic compounds from phomopsis sp., ...201627842536
o-specific polysaccharide-specific memory b cell responses in young children, older children, and adults infected with vibrio cholerae o1 ogawa in bangladesh.cholera caused by vibrio cholerae o1 confers at least 3 to 10 years of protection against subsequent disease regardless of age, despite a relatively rapid fall in antibody levels in peripheral blood, suggesting that memory b cell responses may play an important role in protection. the v. cholerae o1-specific polysaccharide (osp) component of lipopolysaccharide (lps) is responsible for serogroup specificity, and it is unclear if young children are capable of developing memory b cell responses aga ...201627009211
isolation and molecular identification of vibrio spp. by sequencing of 16s rdna from seafood, meat and meat products in libya.the genus vibrio includes several food-borne pathogens that cause a spectrum of clinical conditions including septicemia, cholera and milder forms of gastroenteritis. several vibrio spp. are commonly associated with food-borne transmission including vibrio cholerae, vibrio parahemolyticus, and vibrio vulnificus. microbiological analysis for enumeration and isolation of vibrio spp. were carried out for a total of 93 samples of seafood, meat and meat products from different geographic localities i ...201627004169
single-dose live oral cholera vaccine cvd 103-hgr protects against human experimental infection with vibrio cholerae o1 el tor.no licensed cholera vaccine is presently available in the united states. cholera vaccines available in other countries require 2 spaced doses. a single-dose cholera vaccine that can rapidly protect short-notice travelers to high-risk areas and help control explosive outbreaks where logistics render 2-dose immunization regimens impractical would be a major advance.pxvx0200, based on live attenuated vibrio cholerae o1 classical inaba vaccine strain cvd 103-hgr, elicits seroconversion of vibriocida ...201627001804
genetic characterization of øvc8 lytic phage for vibrio cholerae o1.epidemics and pandemics of cholera, a diarrheal disease, are attributed to vibrio cholera serogroups o1 and o139. in recent years, specific lytic phages of v. cholera have been proposed to be important factors in the cyclic occurrence of cholera in endemic areas. however, the role and potential participation of lytic phages during long interepidemic periods of cholera in non-endemic regions have not yet been described. the purpose of this study was to isolate and characterize specific lytic phag ...201627000701
rpos is required for natural transformation of vibrio cholerae through regulation of chitinases.vibrio species naturally reside in the aquatic environment and a major metabolite in this habitat is the chitinous exoskeletons of crustacean zooplankton. in addition to serving as a nutrient, chitin-derived oligosaccharides also induce natural genetic competence in many vibrio spp., a physiological state in which bacteria take up dna from the extracellular environment and can integrate it into their chromosome by homologous recombination. another inducing cue required for competence are quorum- ...201626999629
draft genome sequence of an ortho-nitrophenyl-β-d-galactoside (onpg)-negative strain of vibrio cholerae, isolated from drakes bay, california.we present the draft whole-genome sequence of a vibrio cholerae strain (vc25-3) isolated from drakes bay, california. this environmental isolate has an atypical morphology and is ortho-nitrophenyl-β-d-galactoside (onpg)-negative.201626988050
6-gingerol inhibits vibrio cholerae-induced proinflammatory cytokines in intestinal epithelial cells via modulation of nf-κb.context the effect of 6-gingerol (6g), the bioactive component of zingiber officinale roscoe (zingiberaceae), in the reduction of vibrio cholerae (vibrionaceae)-induced inflammation has not yet been reported. materials and methods cell viability assay was performed to determine the working concentration of 6g. elisa and rt-pcr were performed with int 407 cells treated with 50 μm 6g and 100 multiplicity of infection (moi) v. cholerae for 0, 2, 3, 3.5, 6 and 8 h to determine the concentration of i ...201626987371
the impact of spatial arrangements on epidemic disease dynamics and intervention strategies.the role of spatial arrangements on the spread and management strategies of a cholera epidemic is investigated. we consider the effect of human and pathogen movement on optimal vaccination strategies. a metapopulation model is used, incorporating a susceptible-infected-recovered system of differential equations coupled with an equation modelling the concentration of vibrio cholerae in an aquatic reservoir. the model compared spatial arrangements and varying scenarios to draw conclusions on how t ...201626981710
phylogenetic diversity of vibrio cholerae associated with endemic cholera in mexico from 1991 to 2008.an outbreak of cholera occurred in 1991 in mexico, where it had not been reported for more than a century and is now endemic. vibrio cholerae o1 prototype el tor and classical strains coexist with altered el tor strains (1991 to 1997). nontoxigenic (ctx(-)) v. cholerae el tor dominated toxigenic (ctx(+)) strains (2001 to 2003), but v. cholerae ctx(+) variant el tor was isolated during 2004 to 2008, outcompeting ctx(-) v. cholerae. genomes of six mexican v. cholerae o1 strains isolated during 199 ...201626980836
construction and preclinical evaluation of mmct, a novel mutant cholera toxin adjuvant that can be efficiently produced in genetically manipulated vibrio cholerae.there is an urgent need for new adjuvants that are effective with mucosally administered vaccines. cholera toxin (ct) is the most powerful known mucosal adjuvant but is much too toxic for human use. in an effort to develop a useful mucosal adjuvant we have generated a novel non-toxic mutant ct molecule that retains much of the adjuvant activity of native ct. this was achieved by making the enzymatically active a subunit (cta) recalcitrant to the site-specific proteolytic cleavage ("nicking") req ...201626973069
high-resolution spatial analysis of cholera patients reported in artibonite department, haiti in 2010-2011.cholera is caused by vibrio cholerae, and is transmitted through fecal-oral contact. infection occurs after the ingestion of the bacteria and is usually asymptomatic. in a minority of cases, it causes acute diarrhea and vomiting, which can lead to potentially fatal severe dehydration, especially in the absence of appropriate medical care. immunity occurs after infection and typically lasts 6-36 months. cholera is responsible for outbreaks in many african and asian developing countries, and cause ...201626972509
comparison of the sulfonamide inhibition profiles of the α-, β- and γ-carbonic anhydrases from the pathogenic bacterium vibrio cholerae.carbonic anhydrases (ca, ec 4.2.1.1) are ubiquitous metalloenzymes, which catalyze the conversion of carbon dioxide (co2) to bicarbonate (hco3(-)) and protons (h(+)). in prokaryotes, the existence of genes encoding for α-, β- and γ-classes suggests that these enzymes play an important role in the prokaryotic physiology. it has been demonstrated, in fact, that their inhibition in vivo leads to growth impairment or growth defects of the microorganism. ultimately, we started to investigate the bioc ...201626972117
the antimicrobial activity of zno nanoparticles against vibrio cholerae: variation in response depends on biotype.the potency of zinc oxide nanoparticles (nps), with a core size of ~7-10nm, to inhibit cholera disease was investigated by demonstrating the effect on two biotypes (classical and el tor) of o1 serogroup of vibrio cholerae-el tor was more susceptible both in planktonic and in biofilm forms. interaction with zno np results in deformed cellular architecture. increased fluidity and depolarization of membrane, and protein leakage further confirmed the damages inflicted on vibrio by np. np was shown t ...201626970029
[effect of osmotic and oxidative stress on strains of genovariants of vibrio cholerae el tor biovar].study the effect of osmotic and oxidative stress on survivability and changes in phenotypic and genetic properties of strains of genovariants of v. cholerae el tor biovar.201626950990
[determination of types of epidemic manifestations of cholera in regions of the crimea federal district (republic of crimea)].the aim of the study was determination of the type of epidemic manifestations of cholera in the republic of crimea based on evaluation of epidemic manifestations of cholera risk of introduction and spread of the infection. it was concluded, that, based on the cholera outbreaks, that had taken place, contamination of surface water bodies (fresh and sea) and sewage by vibrio cholerae o1 ctxa+ and vibrio cholerae o1 ctxa- potential epidemic danger of introduction of the infection by various types o ...201626950987
cell division licensing in the multi-chromosomal vibrio cholerae bacterium.cell division must be coordinated with chromosome replication and segregation to ensure the faithful transmission of genetic information during proliferation. in most bacteria, assembly of the division apparatus, the divisome, starts with the polymerization of a tubulin homologue, ftsz, into a ring-like structure at mid-cell, the z-ring(1). it typically occurs at half of the cell cycle when most of the replication and segregation cycle of the unique chromosome they generally harbour is achieved( ...201627562255
rugose atypical vibrio cholerae o1 el tor responsible for 2009 cholera outbreak in india.vibrio cholerae causes cholera outbreaks in endemic regions where the water quality and sanitation facilities remain poor. apart from biotype and serotype changes, v. cholerae undergoes phase variation, which results in the generation of two morphologically different variants termed smooth and rugose. in this study, 12 rugose (r-vc) and 6 smooth (s-vc) v. cholerae o1 ogawa isolates were identified in a cholera outbreak that occurred in hyderabad, india. antimicrobial susceptibility results showe ...201627561681
phenotypic and genetic heterogeneity in vibrio cholerae o139 isolated from cholera cases in delhi, india during 2001-2006.incidence of epidemic vibrio cholerae serogroup o139 has declined in cholera endemic countries. however, sporadic cholera caused by v. cholerae o139 with notable genetic changes is still reported from many regions. in the present study, 42 v. cholerae o139 strains isolated from 2001 to 2006 in delhi, india, were retrospectively analyzed to understand their phenotype and molecular characteristics. the majority of isolates were resistant to ampicillin, furazolidone and nalidixic acid. though the i ...201627555841
vibrio cholerae biofilm growth program and architecture revealed by single-cell live imaging.biofilms are surface-associated bacterial communities that are crucial in nature and during infection. despite extensive work to identify biofilm components and to discover how they are regulated, little is known about biofilm structure at the level of individual cells. here, we use state-of-the-art microscopy techniques to enable live single-cell resolution imaging of a vibrio cholerae biofilm as it develops from one single founder cell to a mature biofilm of 10,000 cells, and to discover the f ...201627555592
vibrio cholerae leuo links the toxr regulon to expression of lipid a remodeling genes.vibrio cholerae is an intestinal pathogen that causes the diarrheal disease cholera. colonization of the intestine depends upon the expression of genes that allow v. cholerae to overcome host barriers, including low ph, bile acids, and the innate immune system. toxr is a major contributor to this process. toxr is a membrane-spanning transcription factor that coordinates gene expression in response to environmental cues. in previous work we showed that toxr upregulated leuo expression in response ...201627550934
molecular evolution and functional divergence of vibrio cholerae.the purpose of this review is to synopsize and highlight the recent subtle genetic changes in cholera causing toxigenic vibrio cholerae with special reference to their virulence, integrating and conjugative elements and toxin-antitoxin systems. it is not intended to cover issues on the whole genome sequence and epidemiology of cholera.201627537830
vibrio cholerae o1 imported from iraq to kuwait, 2015. 201627532267
vibriosis, not cholera: toxigenic vibrio cholerae non-o1, non-o139 infections in the united states, 1984-2014.toxigenic strains of vibrio cholerae serogroups o1 and o139 have caused cholera epidemics, but other serogroups - such as o75 or o141 - can also produce cholera toxin and cause severe watery diarrhoea similar to cholera. we describe 31 years of surveillance for toxigenic non-o1, non-o139 infections in the united states and map these infections to the state where the exposure probably originated. while serogroups o75 and o141 are closely related pathogens, they differ in how and where they infect ...201627510301
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
catalases and phob/phor system independently contribute to oxidative stress resistance in vibrio cholerae o1.all cells are subjected to oxidative stress, a condition under which reactive oxygen species (ros) production exceeds elimination. bacterial defences against ros include synthesis of antioxidant enzymes like peroxidases and catalases. vibrio cholerae can produce two distinct catalases, katb and katg, which contribute to ros homeostasis. in this study, we analysed the mechanism behind katg and katb expression in two v. cholerae o1 pandemic strains, o395 and n16961, of classical and el tor biotype ...201627665757
role of the na(+)-translocating nadh:quinone oxidoreductase in voltage generation and na(+) extrusion in vibrio cholerae.for vibrio cholerae, the coordinated import and export of na(+) is crucial for adaptation to habitats with different osmolarities. we investigated the na(+)-extruding branch of the sodium cycle in this human pathogen by in vivo (23)na-nmr spectroscopy. the na(+) extrusion activity of cells was monitored after adding glucose which stimulated respiration via the na(+)-translocating nadh:quinone oxidoreductase (na(+)-nqr). in a v. cholerae deletion mutant devoid of the na(+)-nqr encoding genes (nqr ...201626721205
cholera toxin production induced upon anaerobic respiration is suppressed by glucose fermentation in vibrio cholerae.the causative agent of pandemic cholera, vibrio cholerae, infects the anaerobic environment of the human intestine. production of cholera toxin (ct), a major virulence factor of v. cholerae, is highly induced during anaerobic respiration with trimethylamine n-oxide (tmao) as an alternative electron acceptor. however, the molecular mechanism of tmao-stimulated ct production is not fully understood. herein, we reveal that ct production during anaerobic tmao respiration is affected by glucose ferme ...201626718467
validity of the estimates of oral cholera vaccine effectiveness derived from the test-negative design.the test-negative design (tnd) has emerged as a simple method for evaluating vaccine effectiveness (ve). its utility for evaluating oral cholera vaccine (ocv) effectiveness is unknown. we examined this method's validity in assessing ocv effectiveness by comparing the results of tnd analyses with those of conventional cohort analyses.201626707378
a luminescent hybridoma-based biosensor for rapid detection of v. cholerae upon induction of calcium signaling pathway.in this study, a hybridoma based biosensor was developed for rapid, sensitive and selective detection of vibrio cholerae o1 which converts the antibody-antigen binding to bioluminescence light. after investigation on hybridoma performance, the biosensor was constructed by transfecting specific hybridoma cells with aequorin reporter gene and the bioluminescence activities of stable biosensor were measured. the sensitivity of biosensor was as few as 50 cfu/ml and it showed no responses to other en ...201626706943
starch dust explosion and flame burn injury in a patient complicated with severe cellulites caused by non-o1 vibrio cholerae. 201626687236
characterization of environmental vibrio cholerae serogroups o1 and o139 in the pearl river estuary, china.toxigenic isolates of vibrio cholerae serogroups o1 and o139 from aquatic reservoirs are a key source for recurrent epidemics of cholera in human populations. however, we do not have an optimal understanding of the microbiology of the strains within these reservoirs, particularly outside of the time periods when there are active cholera cases in the surrounding community. the main objective of the present study was to identify and characterize v. cholerae o1 and o139 in the pearl river estuary a ...201626674584
detection and quantification of vibrio cholerae, vibrio parahaemolyticus, and vibrio vulnificus in coastal waters of guinea-bissau (west africa).v. cholerae, v. parahaemolyticus, and v. vulnificus are recognized human pathogens. although several studies are available worldwide, both on environmental and clinical contexts, little is known about the ecology of these vibrios in african coastal waters. in this study, their co-occurrence and relationships to key environmental constraints in the coastal waters of guinea-bissau were examined using the most probable number-polymerase chain reaction (mpn-pcr) approach. all vibrio species were uni ...201626940502
an in silico, in vitro and in vivo investigation of indole-3-carboxaldehyde identified from the seawater bacterium marinomonas sp. as an anti-biofilm agent against vibrio cholerae o1.biofilm formation is a major contributing factor in the pathogenesis of vibrio cholerae o1 (vco1) and therefore preventing biofilm formation could be an effective alternative strategy for controlling cholera. the present study was designed to explore seawater bacteria as a source of anti-biofilm agents against vco1. indole-3-carboxaldehyde (i3c) was identified as an active principle component in marinomonas sp., which efficiently inhibited biofilm formation by vco1 without any selection pressure ...201626939983
naturally occurring igg antibodies provide innate protection against vibrio cholerae bacteremia by recognition of the outer membrane protein u.cholera epidemics are caused by vibrio cholerae serogroups o1 and o139, whereas strains collectively known as non-o1/non-o139 v. cholerae are found in cases of extraintestinal infections and bacteremia. the mechanisms and factors influencing the occurrence of bacteremia and survival of v. cholerae in normal human serum have remained unclear. we found that naturally occurring igg recognizing v. cholerae outer membrane protein u (ompu) mediates a serum-killing effect in a complement c1q-dependent ...201626934383
architectural transitions in vibrio cholerae biofilms at single-cell resolution.many bacterial species colonize surfaces and form dense 3d structures, known as biofilms, which are highly tolerant to antibiotics and constitute one of the major forms of bacterial biomass on earth. bacterial biofilms display remarkable changes during their development from initial attachment to maturity, yet the cellular architecture that gives rise to collective biofilm morphology during growth is largely unknown. here, we use high-resolution optical microscopy to image all individual cells i ...201626933214
the transmission and antibiotic resistance variation in a multiple drug resistance clade of vibrio cholerae circulating in multiple countries in asia.vibrio cholerae has caused massive outbreaks and even trans-continental epidemics. in 2008 and 2010, at least 3 remarkable cholera outbreaks occurred in hainan, anhui and jiangsu provinces of china. to address the possible transmissions and the relationships to the 7th pandemic strains of those 3 outbreaks, we sequenced the whole genomes of the outbreak isolates and compared with the global isolates from the 7th pandemic. the three outbreaks in this study were caused by a cluster of v. cholerae ...201626930352
non-o1vibrio cholerae bacteremia in an infant, first case report from pakistan.to the best of our knowledge, non-o1 vibrio cholerae (novc) bacteremia has never been documented in pakistan. this case report is the first reported case of bacteremia in an infant due to novc in pakistan. a neonate was admitted to a hospital with fever and no history of diarrhea. the isolate was identified biochemically and serologically and was sensitive to all the drugs tested as per clsi 2014 guidelines.201626927462
us gulf-like toxigenic o1 vibrio cholerae causing sporadic cholera outbreaks in china.cholera is potentially a life threatening disease caused by toxigenic vibrio cholerae. here we report the identification and characterisation of 76 non-7th pandemic clone o1 v. cholerae isolates including 65 clinical isolates from diarrhoeal patients from 2005 to 2014 in zhejiang province, china.201626920786
extraintestinal infections caused by non-toxigenic vibrio cholerae non-o1/non-o139.vibrio cholerae is an aerobic, sucrose fermentative gram-negative bacterium that generally prevails in the environment. pathogenic v. cholerae is well-known as causative agent of acute diarrhea. apart from enteric infections, v. cholerae may also cause other diseases. however, their role in causing extraintestinal infections is not fully known as it needs proper identification and evaluation. four cases of extraintestinal infections due to v. cholerae non-o1/non-o139 have been investigated. the ...201626904017
in vitro inhibition of cholera toxin production in vibrio cholerae by methanol extract of sweet fennel seeds and its components.a newly emerged vibrio cholerae o1 el tor variant strain with multidrug resistance is considered a threat to public health. recent strategies to suppress virulence factors production instead of bacterial growth may lead to less selective pressure for the emergence of resistant strains. the use of spices and their active constituents as the inhibitory agents against cholera toxin (ct) production in v. cholerae may be an alternative approach to treat cholera. in this study, we examined the potenti ...201626902215
chemoproteomic profiling of host and pathogen enzymes active in cholera.activity-based protein profiling (abpp) is a chemoproteomic tool for detecting active enzymes in complex biological systems. we used abpp to identify secreted bacterial and host serine hydrolases that are active in animals infected with the cholera pathogen vibrio cholerae. four v. cholerae proteases were consistently active in infected rabbits, and one, vc0157 (renamed ivap), was also active in human choleric stool. inactivation of ivap influenced the activity of other secreted v. cholerae and ...201626900865
par-1 mediated apoptosis of breast cancer cells by v. cholerae hemagglutinin protease.bacterial toxins have emerged as promising agents in cancer treatment strategy. hemagglutinin (hap) protease secreted by vibrio cholerae induced apoptosis in breast cancer cells and regresses tumor growth in mice model. the success of novel cancer therapies depends on their selectivity for cancer cells with limited toxicity for normal tissues. increased expression of protease activated receptor-1 (par-1) has been reported in different malignant cells. in this study we report that hap induced act ...201626897170
the oral cholera vaccine shanchol™ when stored at elevated temperatures maintains the safety and immunogenicity profile in bangladeshi participants.the oral cholera vaccine (ocv), shanchol™ has shown protective efficacy lasting up to 5 years, however, requirement for a cold chain limits its use in resource poor settings. the study was conducted to determine the safety and immunogenicity of shanchol in adult participants in bangladesh when stored at elevated temperatures.201626896684
adjusting for unmeasured confounding due to either of two crossed factors with a logistic regression model.motivated by an investigation of the effect of surface water temperature on the presence of vibrio cholerae in water samples collected from different fixed surface water monitoring sites in haiti in different months, we investigated methods to adjust for unmeasured confounding due to either of the two crossed factors site and month. in the process, we extended previous methods that adjust for unmeasured confounding due to one nesting factor (such as site, which nests the water samples from diffe ...201626892025
identification of a vibrio cholerae chemoreceptor that senses taurine and amino acids as attractants.vibrio cholerae, the etiological agent of cholera, was found to be attracted by taurine (2-aminoethanesulfonic acid), a major constituent of human bile. mlp37, the closest homolog of the previously identified amino acid chemoreceptor mlp24, was found to mediate taxis to taurine as well as l-serine, l-alanine, l-arginine, and other amino acids. methylation of mlp37 was enhanced upon the addition of taurine and amino acids. isothermal titration calorimetry demonstrated that a purified periplasmic ...201626878914
oligonol promotes anti-aging pathways via modulation of sirt1-ampk-autophagy pathway.oligonol, mainly found in lychee fruit, is an antioxidant polyphenolic compound which has been shown to have anti-inflammatory and anti-cancer properties. the detailed mechanisms by which oligonol may act as an anti-aging molecule have not been determined.201626865910
anion inhibition studies of the β-carbonic anhydrase from the pathogenic bacterium vibrio cholerae.the genome of the pathogenic bacterium vibrio cholerae encodes for three carbonic anhydrases (cas, ec 4.2.1.1) belonging to the α-, β- and γ-classes. here we report and anion inhibition study of the β-ca, vchcaβ with anions and other small molecules which inhibit metalloenzymes. the best vchcaβ anion inhibitors were sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid, which showed kis in the range of 54-86μm. diethyldithiocarbonate was also an effective vchcaβ inhibitor, with an inhi ...201626853167
enterobacteria and vibrio from macrobrachium amazonicum prawn farming in fortaleza, ceará, brazil.to investigate the isolation of enterobacteria associated with macrobrachium amazonicum (m. amazonicum) farming and evaluate the in vitro antimicrobial susceptibility of vibrio strains.201626851782
sulfonamide inhibition studies of the β-carbonic anhydrase from the pathogenic bacterium vibrio cholerae.the genome of the pathogenic bacterium vibrio cholerae encodes for three carbonic anhydrases (cas, ec 4.2.1.1) belonging to the α-, β- and γ-classes. vchca, the α-ca from this species was investigated earlier, whereas the β-class enzyme, vchcaβ was recently cloned, characterized kinetically and its x-ray crystal structure reported by this group. here we report an inhibition study with sulfonamides and one sulfamate of this enzyme. the best vchcaβ inhibitors were deacetylated acetazolamide and me ...201626850377
role of vibrio cholerae exochitinase chia2 in horizontal gene transfer.vibrio cholerae exochitinase chia2 plays a key role in acquisition of nutrients by chitin hydrolysis in the natural environment as well as in pathogenesis in the intestinal milieu. in this study we demonstrate the importance of chia2 in horizontal gene transfer in the natural environment. we found that the expression of chia2 and tfox, the central regulator of v. cholerae horizontal gene transfer, varied with changes in environmental conditions. the activity of chia2 was also dependent on these ...201626849349
the rna domain vc1 regulates downstream gene expression in response to cyclic diguanylate in vibrio cholerae.in many bacterial species, including the aquatic bacterium and human pathogen vibrio cholerae, the second messenger cyclic diguanylate (c-di-gmp) modulates processes such as biofilm formation, motility, and virulence factor production. by interacting with various effectors, c-di-gmp regulates gene expression or protein function. one type of c-di-gmp receptor is the class i riboswitch, representatives of which have been shown to bind c-di-gmp in vitro. herein, we examined the in vitro and in vivo ...201626849223
vibrio cholerae biofilms and cholera pathogenesis.vibrio cholerae can switch between motile and biofilm lifestyles. the last decades have been marked by a remarkable increase in our knowledge of the structure, regulation, and function of biofilms formed under laboratory conditions. evidence has grown suggesting that v. cholerae can form biofilm-like aggregates during infection that could play a critical role in pathogenesis and disease transmission. however, the structure and regulation of biofilms formed during infection, as well as their role ...201626845681
the bacterial dicarboxylate transporter vcindy uses a two-domain elevator-type mechanism.secondary transporters use alternating-access mechanisms to couple uphill substrate movement to downhill ion flux. most known transporters use a 'rocking bundle' motion, wherein the protein moves around an immobile substrate-binding site. however, the glutamate-transporter homolog gltph translocates its substrate-binding site vertically across the membrane, through an 'elevator' mechanism. here, we used the 'repeat swap' approach to computationally predict the outward-facing state of the na(+)/s ...201626828963
biochemical and full genome sequence analyses of clinical vibrio cholerae isolates in mexico reveals the presence of novel v. cholerae strains.the first week of september 2013, the national epidemiological surveillance system identified two cases of cholera in mexico city. the cultures of both samples were confirmed as vibrio cholerae serogroup o1, serotype ogawa, biotype el tor. initial analyses by pfge and by pcr-amplification of the virulence genes, suggested that both strains were similar, but different from those previously reported in mexico. the following week, four more cases were identified in a community in the state of hidal ...201626828665
necrotizing fasciitis due to vibrio cholerae non-o1/non-o139 after exposure to austrian bathing sites.we report on two cases of necrotizing fasciitis of the lower leg due to nontoxigenic vibrio cholerae (v. cholerae). a 73-year-old woman (case 1) and an 80-year-old man (case 2) were hospitalized with symptoms of necrotizing fasciitis on july 18 and august 15, 2015, respectively. in both cases, symptoms started the day after swimming in local ponds. swabs gained intraoperatively and a blood culture from the male patient, yielded v. cholerae non-o1/non-o139, negative for cholera toxin gene ctx and ...201626825075
notes from the field: ongoing cholera outbreak - kenya, 2014-2016.on january 6, 2015, a man aged 40 years was admitted to kenyatta national hospital in nairobi, kenya, with acute watery diarrhea. the patient was found to be infected with toxigenic vibrio cholerae serogroup o1, serotype inaba. a subsequent review of surveillance reports identified four patients in nairobi county during the preceding month who met either of the kenya ministry of health suspected cholera case definitions: 1) severe dehydration or death from acute watery diarrhea (more than four e ...201626820494
strategies to prevent cholera introduction during international personnel deployments: a computational modeling analysis based on the 2010 haiti outbreak.introduction of vibrio cholerae to haiti during the deployment of united nations (un) peacekeepers in 2010 resulted in one of the largest cholera epidemics of the modern era. following the outbreak, a un-commissioned independent panel recommended three pre-deployment intervention strategies to minimize the risk of cholera introduction in future peacekeeping operations: screening for v. cholerae carriage, administering prophylactic antimicrobial chemotherapies, or immunizing with oral cholera vac ...201626812236
randomized controlled trial of hospital-based hygiene and water treatment intervention (chobi7) to reduce cholera.the risk for cholera infection is >100 times higher for household contacts of cholera patients during the week after the index patient seeks hospital care than it is for the general population. to initiate a standard of care for this high-risk population, we developed cholera-hospital-based-intervention-for-7-days (chobi7), which promotes hand washing with soap and treatment of water. to test chobi7, we conducted a randomized controlled trial among 219 intervention household contacts of 82 chole ...201626811968
comparative transcriptome analysis of vibrio splendidus jz6 reveals the mechanism of its pathogenicity at low temperatures.yesso scallop-pathogenic vibrio splendidus strain jz6 was found to have the highest virulence at 10°c, while its pathogenicity was significantly reduced with increased temperature and completely incapacitated at 28°c. in the present study, comparative transcriptome analyses of jz6 and another nonpathogenic v. splendidus strain, tz19, were conducted at two crucial culture temperatures (10°c and 28°c) in order to determine the possible mechanism of temperature regulation of virulence. comparisons ...201626801576
occurrence and molecular characterisation of vibrio parahaemolyticus in crustaceans commercialised in venice area, italy.infections due to the pathogenic human vibrios, vibrio parahaemolyticus, vibrio cholerae and vibrio vulnificus, are mainly associated with consumption of raw or partially cooked bivalve molluscs. at present, little is known about the presence of vibrio species in crustaceans and the risk of vibriosis associated with the consumption of these products. the aim of the present study was to evaluate the prevalence and concentration of the main pathogenic vibrio spp. in samples of crustaceans (n=143) ...201626773255
imported cholera with acute renal failure after a short business-trip to the philippines, germany, october 2015.a german businessman developed acute watery diarrhoea after a three-day trip to the philippines. he was admitted with severe hypotension and acute renal failure, but recovered with rapid rehydration. vibrio cholerae o1 serotype ogawa was isolated. physicians need to be aware of endemic cholera in asia including the philippines and consider this in their pre-travel advice.201626767388
clinical and environmental surveillance for vibrio cholerae in resource constrained areas: application during a 1-year surveillance in the far north region of cameroon.biological confirmation of the presence of vibrio cholerae in clinical and environmental samples is often constrained due to resource- and labor-intensive gold standard methods. to develop low-cost, simple, and sustainable surveillance techniques, we modified previously published specimen sampling and culture techniques and applied the use of enriched dipstick testing in conjunction with the use of filter paper for dna specimen preservation during clinical and environmental surveillance in the f ...201626755564
evaluation in cameroon of a novel, simplified methodology to assist molecular microbiological analysis of v. cholerae in resource-limited settings.vibrio cholerae is endemic in south asia and africa where outbreaks of cholera occur widely and are particularly associated with poverty and poor sanitation. knowledge of the genetic diversity of toxigenic v. cholerae isolates, particularly in africa, remains scarce. the constraints in improving this understanding is not only the lack of regular cholera disease surveillance, but also the lack of laboratory capabilities in endemic countries to preserve, store and ship isolates in a timely manner. ...201626735969
hybrid microarray based on double biomolecular markers of dna and carbohydrate for simultaneous genotypic and phenotypic detection of cholera toxin-producing vibrio cholerae.life-threatening diarrheal cholera is usually caused by water or food contaminated with cholera toxin-producing vibrio cholerae. for the prevention and surveillance of cholera, it is crucial to rapidly and precisely detect and identify the etiological causes, such as v. cholerae and/or its toxin. in the present work, we propose the use of a hybrid double biomolecular marker (dbm) microarray containing 16s rrna-based dna capture probe to genotypically identify v. cholerae and gm1 pentasaccharide ...201626735874
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
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