| classic reaction kinetics can explain complex patterns of antibiotic action. | finding optimal dosing strategies for treating bacterial infections is extremely difficult, and improving therapy requires costly and time-intensive experiments. to date, an incomplete mechanistic understanding of drug effects has limited our ability to make accurate quantitative predictions of drug-mediated bacterial killing and impeded the rational design of antibiotic treatment strategies. three poorly understood phenomena complicate predictions of antibiotic activity: post-antibiotic growth ... | 2015 | 25972005 |
| saxs data based global shape analysis of trigger factor (tf) proteins from e. coli, v. cholerae, and p. frigidicola: resolving the debate on the nature of monomeric and dimeric forms. | dimerization of bacterial chaperone trigger factor (tf) is an inherent protein concentration based property which available biophysical characterization and crystal structures have kept debatable. we acquired small-angle x-ray scattering (saxs) intensity data from different tf homologues from escherichia coli (ectf), vibrio cholerae (vctf), and psychrobacter frigidicola (pftf) while varying each protein concentration. we found that ectf and vctf adopt a compact dimeric shape at higher concentrat ... | 2015 | 25950744 |
| protonography, a powerful tool for analyzing the activity and the oligomeric state of the γ-carbonic anhydrase identified in the genome of porphyromonas gingivalis. | carbonic anhydrases (cas, ec 4.2.1.1) are metalloenzymes, mostly containing zinc within their active site, which catalyze a simple but physiologically relevant reaction in all life kingdoms, carbon dioxide hydration to bicarbonate and protons. six ca classes (α, β, γ, δ, ζ and η) and multiple ca isoforms evolved in organisms all over the phylogenetic tree, for facing the need to efficiently convert high amounts of co2 to its hydration products. these enzymes are thus involved in many physiologic ... | 2015 | 25910585 |
| antibacterial and antispasmodic activities of a dichloromethane fraction of an ethanol extract of stem bark of piliostigma reticulatum. | this study presents the antispasmodic and antibacterial properties of an ethanol extract and fractions the of stem bark of piliostigma reticulatum. | 2017 | 25883517 |
| structural basis for the catalytic mechanism of dncv, bacterial homolog of cyclic gmp-amp synthase. | cyclic dinucleotides (cdns) play key roles as second messengers and signaling molecules in bacteria and metazoans. the newly identified dinucleotide cyclase in vibrio cholerae (dncv) produces three different cdns containing two 3'-5' phosphodiester bonds, and its predominant product is cyclic gmp-amp, whereas mammalian cyclic gmp-amp synthase (cgas) produces only cyclic gmp-amp containing mixed 2'-5' phosphodiester bonds. we report the crystal structures of v. cholerae and escherichia coli dncv ... | 2015 | 25865248 |
| expression and functional validation of heat-labile enterotoxin b (ltb) and cholera toxin b (ctb) subunits in transgenic rice (oryza sativa). | we expressed the heat-labile enterotoxin b (ltb) subunit from enterotoxigenic escherichia coli and the cholera toxin b (ctb) subunit from vibrio cholerae under the control of the rice (oryza sativa) globulin (glb) promoter. binding of recombinant ltb and ctb proteins was confirmed based on gm1-ganglioside binding enzyme-linked immunosorbent assays (gm1-elisa). real-time pcr of three generations (t3, t4, and t5) in homozygous lines (lci-11) showed single copies of ltb, ctb, bar and tnos. ltb and ... | 2015 | 25853032 |
| active site and remote contributions to catalysis in methylthioadenosine nucleosidases. | 5'-methylthioadenosine/s-adenosyl-l-homocysteine nucleosidases (mtans) catalyze the hydrolysis of 5'-methylthioadenosine to adenine and 5-methylthioribose. the amino acid sequences of the mtans from vibrio cholerae (vcmtan) and escherichia coli (ecmtan) are 60% identical and 75% similar. protein structure folds and kinetic properties are similar. however, binding of transition-state analogues is dominated by favorable entropy in vcmtan and by enthalpy in ecmtan. catalytic sites of vcmtan and ecm ... | 2015 | 25806409 |
| bottom-up and top-down solid-state nmr approaches for bacterial biofilm matrix composition. | the genomics and proteomics revolutions have been enormously successful in providing crucial "parts lists" for biological systems. yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and ... | 2015 | 25797008 |
| secretome analysis of vibrio cholerae type vi secretion system reveals a new effector-immunity pair. | the type vi secretion system (t6ss) is a dynamic macromolecular organelle that many gram-negative bacteria use to inhibit or kill other prokaryotic or eukaryotic cells. the toxic effectors of t6ss are delivered to the prey cells in a contact-dependent manner. in vibrio cholerae, the etiologic agent of cholera, t6ss is active during intestinal infection. here, we describe the use of comparative proteomics coupled with bioinformatics to identify a new t6ss effector-immunity pair. this analysis was ... | 2015 | 25759499 |
| hygiene and health risks associated with the consumption of edible lamellibranch molluscs. | edible lamellibranch molluscs are frequently the cause of very serious outbreaks of food poisoning. microbiological suitability for human consumption, according to ec reg. n. 1441/2007, is only based on two faecal bacteriological contamination parameters (escherichia coli and salmonella) and does not consider other microorganisms which are naturally present within the marine environment and are potentially pathogenic such as those belonging to the genus vibrio. in this study, a total of 540 samp ... | 2015 | 25744696 |
| role of integrons, plasmids and sxt elements in multidrug resistance of vibrio cholerae and providencia vermicola obtained from a clinical isolate of diarrhea. | the isolates of vibrio cholerae and providencia vermicola obtained from a diarrheal patient were investigated for genetic elements governing their drug resistance phenotypes. out of 14 antibiotics tested, v. cholerae vc idh02365 isolate showed resistance to nine antibiotics, while p. vermicola pv nba2365 was found to be resistant to all the antibiotics except polymyxin b. though sxt integrase was depicted in both the bacteria, class 1 integron was found to be associated only with pv nba2365. int ... | 2015 | 25741322 |
| functional analysis of vibrio vulnificus rnd efflux pumps homologous to vibrio cholerae vexab and vexcd, and to escherichia coli acrab. | resistance-nodulation-division (rnd) efflux pumps are associated with multidrug resistance in many gram-negative pathogens. the genome of vibrio vulnificus encodes 11 putative rnd pumps homologous to those of vibrio cholerae and escherichia coli. in this study, we analyzed three putative rnd efflux pumps, showing homology to v. cholerae vexab and vexcd and to e. coli acrab, for their functional roles in multidrug resistance of v. vulnificus. deletion of the vexab homolog resulted in increased su ... | 2015 | 25740377 |
| recombinant toxin-coregulated pilus a (tcpa) as a candidate subunit cholera vaccine. | the toxin co-regulated pilus a (tcpa) has been described as a critical pathogenicity factor of vibrio cholerae. tcpa is a candidate for making subunit vaccine against cholera. the aim of this study was to produce a candidate vaccine by expressing recombinant tcpa in e. coli. | 2014 | 25705354 |
| protonography, a technique applicable for the analysis of η-carbonic anhydrase activity. | protonography, a sodium dodecyl sulfate - polyacrylamide gel electrophoresis (sds-page) technique derived from zymography was recently reported by our group to be an effective, cheap and reproducible technique for evidencing catalytically active α-carbonic anhydrase (ca, ec 4.2.1.1) isoforms, such as the bovine red blood cell isoform bca or the bacterial enzyme from vibrio cholerae, vchca. ca activity was also observed on the protonogram of a cellular extract of escherichia coli, evidencing the ... | 2015 | 25676328 |
| 'big things in small packages: the genetics of filamentous phage and effects on fitness of their host'. | this review synthesizes recent and past observations on filamentous phages and describes how these phages contribute to host phentoypes. for example, the ctxφ phage of vibrio cholerae encodes the cholera toxin genes, responsible for causing the epidemic disease, cholera. the ctxφ phage can transduce non-toxigenic strains, converting them into toxigenic strains, contributing to the emergence of new pathogenic strains. other effects of filamentous phage include horizontal gene transfer, biofilm de ... | 2015 | 25670735 |
| a d, d-carboxypeptidase is required for vibrio cholerae halotolerance. | the biological roles of low molecular weight penicillin-binding proteins (lmw pbp) have been difficult to discern in gram-negative organisms. in escherichia coli, mutants lacking these proteins often have no phenotype, and cells lacking all seven lmw pbps remain viable. in contrast, we report here that vibrio cholerae lacking daca-1, a pbp5 homologue, displays slow growth, aberrant morphology and altered peptidoglycan (pg) homeostasis in luria-bertani (lb) medium, as well as a profound plating d ... | 2015 | 25631756 |
| a novel polyamine allosteric site of speg from vibrio cholerae is revealed by its dodecameric structure. | spermidine n-acetyltransferase, encoded by the gene speg, catalyzes the initial step in the degradation of polyamines and is a critical enzyme for determining the polyamine concentrations in bacteria. in escherichia coli, studies have shown that speg is the enzyme responsible for acetylating spermidine under stress conditions and for preventing spermidine toxicity. not all bacteria contain speg, and many bacterial pathogens have developed strategies to either acquire or silence it for pathogenes ... | 2015 | 25623305 |
| antibacterial efficacy of five medicinal plants against multidrug-resistant enteropathogenic bacteria infecting under-5 hospitalized children. | to evaluate in vitro antibacterial effectiveness of five medicinal plants used by an indian aborigine, against 8 multidrug-resistant (mdr) enteropathogenic bacteria isolated from clinical samples of under-5 hospitalized children. | 2015 | 25609371 |
| the 40-residue insertion in vibrio cholerae fadr facilitates binding of an additional fatty acyl-coa ligand. | fadr is a master regulator of fatty acid metabolism and influences virulence in certain members of vibrionaceae. among fadr homologues of the gntr family, the vibrionaceae protein is unusual in that it contains a c-terminal 40-residue insertion. here we report the structure of vibrio cholerae fadr (vcfadr) alone, bound to dna, and in the presence of a ligand, oleoyl-coa. whereas escherichia coli fadr (ecfadr) contains only one acyl-coa-binding site in each monomer, crystallographic and calorimet ... | 2015 | 25607896 |
| determinants of percent expenditure of household income due to childhood diarrhoea in rural bangladesh. | there is limited information on percent expenditure of household income due to childhood diarrhoea especially in rural bangladesh. a total of 4205 children aged <5 years with acute diarrhoea were studied. percent expenditure was calculated as total expenditure for the diarrhoeal episode divided by monthly family income, multiplied by 100. overall median percent expenditure was 3·04 (range 0·01-94·35). for vibrio cholerae it was 6·42 (range 0·52-82·85), for enterotoxigenic escherichia coli 3·10 ( ... | 2015 | 25591710 |
| ypfφ: a filamentous phage acquired by yersinia pestis. | yersinia pestis, the plague bacillus, has an exceptional pathogenicity for humans. the plague bacillus emerged very recently (≈3,000 years ago) from the enteropathogen y. pseudotuberculosis. early after its emergence, y. pestis became infected by a filamentous phage named ypfφ. during the microevolution of the plague bacillus, the phage remained in the various lineages as an unstable extrachromosomal element. however, in the sub branch that caused the third plague pandemic, ypfφ integrated itsel ... | 2014 | 25566217 |
| emergence and spread of tetracycline resistant vibrio cholerae o1 el tor variant during 2010 cholera epidemic in the tribal areas of odisha, india. | the epidemics of cholera were reported in the kashipur, k.singhpur, b cuttack blocks of rayagada district and mohana block of gajapati district of odisha during 2010. the present study was carried out to isolate the bacterial pathogen, its drug sensitivity pattern and to describe the spread of the disease in those areas. | 2015 | 25543097 |
| [microbial community of municipal discharges in a sewage treatment plant]. | there are numerous microorganisms, especial pathogens, in the discharges. those microorganisms are discharged into the river and sea through sewage outfalls, which results in possible health risks to coastal populations. and more attention should be paid to municipal discharges in developing countries. this study investigated the microbial community in the discharges by constructing 16s rdna clones library and using the pcr-rflp technology. phylogenetic analysis of bacteria in municipal discharg ... | 2014 | 25518668 |
| antibacterial activity of silver and zinc nanoparticles against vibrio cholerae and enterotoxic escherichia coli. | vibrio cholerae and enterotoxic escherichia coli (etec) remain two dominant bacterial causes of severe secretory diarrhea and still a significant cause of death, especially in developing countries. in order to investigate new effective and inexpensive therapeutic approaches, we analyzed nanoparticles synthesized by a green approach using corresponding salt (silver or zinc nitrate) with aqueous extract of caltropis procera fruit or leaves. we characterized the quantity and quality of nanoparticle ... | 2015 | 25466205 |
| construction of a tetracycline inducible expression vector and characterization of its use in vibrio cholerae. | we report the construction of a tetracycline inducible expression vector that allows regulated gene expression in the enteric pathogen vibrio cholerae. the expression vector, named pxb300, contains the tetracycline regulatory elements from tn10, a multiple cloning site downstream of the teta promoter and operator sequences, a cole1 origin of replication, a β-lactamase resistance gene for positive selection, and the hok/sok addiction system for selection in the absence of antibiotic. the function ... | 2014 | 25451701 |
| synthesis and antibacterial activity evaluation of two androgen derivatives. | in this study two androgen derivatives were synthesized using several strategies; the first stage an aza-steroid derivative (3) was developed by the reaction of a testosterone derivative (1) with thiourea (2) in presence of hydrogen chloride. the second step, involves the synthesis of an amino-steroid derivative (4) by the reaction of 1 with 2 using boric acid as catalyst. the third stage was achieved by the preparation of an aminoaza-androgen derivative (6) by the reaction of 3 with ethylenedia ... | 2015 | 25448363 |
| safety and immunogenicity of escalating dosages of a single oral administration of peru-15 pctb, a candidate live, attenuated vaccine against enterotoxigenic escherichia coli and vibrio cholerae. | enterotoxigenic escherichia coli (etec) organisms are a leading cause of infectious diarrhea in developing countries. a live, attenuated cholera strain that expresses high levels of the nontoxic b subunit of cholera toxin, which might also serve as an etec protective antigen, was evaluated for safety, excretion, and immunogenicity in healthy volunteers. we enrolled four inpatient dose-escalation cohorts of 15 to 16 eligible subjects to randomly (3:1) receive a single oral dose of vaccine or plac ... | 2015 | 25410205 |
| probiotic potential of lactic acid bacteria present in home made curd in southern india. | the human gut microbiota play a significant role in nutritional processes. the concept of probiotics has led to widespread consumption of food preparations containing probiotic microbes such as curd and yogurt. curd prepared at home is consumed every day in most homes in southern india. in this study the home-made curd was evaluated for lactic acid bacteria (lab) with probiotic potential. | 2014 | 25366201 |
| synthetic secondary chromosomes in escherichia coli based on the replication origin of chromosome ii in vibrio cholerae. | recent developments in dna-assembly methods make the synthesis of synthetic chromosomes a reachable goal. however, the redesign of primary chromosomes bears high risks and still requires enormous resources. an alternative approach is the addition of synthetic chromosomes to the cell. the natural secondary chromosome of vibrio cholerae could potentially serve as template for a synthetic secondary chromosome in escherichia coli. to test this assumption we constructed a replicon named synvicii base ... | 2015 | 25359671 |
| biophysical characteristics of cholera toxin and escherichia coli heat-labile enterotoxin structure and chemistry lead to differential toxicity. | the biophysical chemistry of macromolecular complexes confer their functional characteristics. we investigate the mechanisms that make the ab5 holotoxin of vibrio cholerae (ct) a significantly more pathogenic molecule than the enterotoxin of escherichia coli (lt) with which it shares 88% similarity and whose structure is homologous with a backbone rmsd of 0.84 å and imposes its deleterious effects though the same process to constitutively adp-ribosylate adenylate cyclase. we present computationa ... | 2015 | 25322200 |
| characterization of tryptophanase from vibrio cholerae. | tryptophanase (trpase) is a pyridoxal phosphate (plp)-dependent enzyme responsible for the production of indole, an important intra- and interspecies signaling molecule in bacteria. in this study, the tnaa gene of vibrio cholerae coding for vctrpase was cloned into the pet-20b(+) vector and expressed in escherichia coli bl21(de3) tn5:tnaa. using ni(2+)-nitrilotriacetic acid (nta) chromatography, vctrpase was purified, and it possessed a molecular mass of ∼49 kda with specific absorption peaks at ... | 2015 | 25253268 |
| a novel, broad-range, ctxφ-derived stable integrative expression vector for functional studies. | ctxφ, a filamentous vibriophage encoding cholera toxin, uses a unique strategy for its lysogeny. the single-stranded phage genome forms intramolecular base-pairing interactions between two inversely oriented xerc and xerd binding sites (xbs) and generates a functional phage attachment site, attp(+), for integration. the attp(+) structure is recognized by the host-encoded tyrosine recombinases xerc and xerd (xercd), which enables irreversible integration of ctxφ into the chromosome dimer resoluti ... | 2014 | 25225263 |
| aetiologies of diarrhoea in adults from urban and rural treatment facilities in bangladesh. | the objective of our analysis was to describe the aetiology, clinical features, and socio-demographic background of adults with diarrhoea attending different urban and rural diarrhoeal disease hospitals in bangladesh. between january 2010 and december 2011, a total of 5054 adult diarrhoeal patients aged ⩾20 years were enrolled into the diarrhoeal disease surveillance systems at four different hospitals (two rural and two urban) of bangladesh. middle-aged [adjusted odds ratio (aor) 0·28, 95% conf ... | 2015 | 25222698 |
| detection of enteric viral and bacterial pathogens associated with paediatric diarrhoea in goroka, papua new guinea. | the aim of this study was to investigate the viral and bacterial causes of acute watery diarrhoea in hospitalized children in papua new guinea. | 2014 | 25193391 |
| cell separation in vibrio cholerae is mediated by a single amidase whose action is modulated by two nonredundant activators. | synthesis and hydrolysis of septal peptidoglycan (pg) are critical processes at the conclusion of cell division that enable separation of daughter cells. cleavage of septal pg is mediated by pg amidases, hydrolytic enzymes that release peptide side chains from the glycan strand. most gammaproteobacteria, including escherichia coli, encode several functionally redundant periplasmic amidases. however, members of the vibrio genus, including the enteric pathogen vibrio cholerae, encode only a single ... | 2014 | 25182499 |
| water bags as a potential vehicle for transmitting disease in a west african capital, bissau. | street vendors of chilled packaged water have an increasing role in meeting the drinking water demand of people on the move in developing nations. hygienic conditions can be questionable, and water quality screening scarce or non-existent. | 2015 | 25164169 |
| genetic elements associated with antimicrobial resistance among intestinal bacteria. | integrons are the major reasons of multidrug resistance (mdr) among enteropathogenic bacteria. occurrence of horizontal gene transfer between integron-carrying microorganisms and other enteric bacteria may increase the rate of emergence of integron-associated antibiotic resistance. | 2014 | 25147720 |
| modeling of scale-dependent bacterial growth by chemical kinetics approach. | we applied the so-called chemical kinetics approach to complex bacterial growth patterns that were dependent on the liquid-surface-area-to-volume ratio (sa/v) of the bacterial cultures. the kinetic modeling was based on current experimental knowledge in terms of autocatalytic bacterial growth, its inhibition by the metabolite co2, and the relief of inhibition through the physical escape of the inhibitor. the model quantitatively reproduces kinetic data of sa/v-dependent bacterial growth and can ... | 2014 | 25105169 |
| crystallization and preliminary x-ray analysis of a ribokinase from vibrio cholerae o395. | ribokinase (rk) is one of the principal enzymes in carbohydrate metabolism, catalyzing the reaction of d-ribose and adenosine triphosphate to produce ribose-5-phosphate and adenosine diphosphate (adp). to provide further insight into the catalytic mechanism, the rbsk gene from vibrio cholerae o395 encoding ribokinase was cloned and the protein was overexpressed in escherichia coli bl21 (de3) and purified using ni(2+)-nta affinity chromatography. crystals of v. cholerae rk (vc-rk) and of its comp ... | 2014 | 25084391 |
| analysis of bacterial pathogens causing acute diarrhea on the basis of sentinel surveillance in shanghai, china, 2006-2011. | acute diarrhea is the most common infectious disease worldwide and its causes vary from one region to another. we aimed to analyze the spectrum and epidemiological characteristics of pathogens from 22,386 outpatients with acute diarrhea on the basis of surveillance data from shanghai, china, during 2006-2011. the following 8 pathogens were isolated and identified using standard methods: salmonella, shigella, vibrio cholerae, v. parahaemolyticus, enteropathogenic escherichia coli, enterotoxigenic ... | 2014 | 25056071 |
| discovery of a bifunctional acyltransferase responsible for ornithine lipid synthesis in serratia proteamaculans. | ornithine lipids (ols) are phosphorus-free membrane lipids that can be formed by many bacteria but that are absent from archaea and eukaryotes. a function for ols in stress conditions and in host-bacteria interactions has been shown in some bacteria. some bacterial species have been described that can form ols, but lack the known genes (olsba) involved in its biosynthesis, which implied the existence of a second pathway. here we describe the bifunctional protein olsf from serratia proteamaculans ... | 2015 | 25040623 |
| use of plant extracts to control and treat ab5 enterotoxin-related diarrhea. | plants contain a broad spectrum of small molecules with potential antimicrobial properties. here, we review the antimicrobial activities of plant extracts against enterotoxic bacteria encoding ab5 toxins, including vibrio cholerae, shigella dysenteriae and enterotoxic escherichia coli strains. several plant extracts have strong antimicrobial effects and the potential to boost oral rehydration therapy, which is the first line of treatment for acute diarrhea. | 2014 | 25033656 |
| crystallization and preliminary analysis of the nqra and nqrc subunits of the na+-translocating nadh:ubiquinone oxidoreductase from vibrio cholerae. | the na+-translocating nadh:ubiquinone oxidoreductase (na+-nqr) from vibrio cholerae is a membrane protein complex consisting of six different subunits nqra-nqrf. the major domains of the nqra and nqrc subunits were heterologously expressed in escherichia coli and crystallized. the structure of nqra1-377 was solved in space groups c222₁ and p2₁ by sad phasing and molecular replacement at 1.9 and 2.1 å resolution, respectively. nqrc devoid of the transmembrane helix was co-expressed with apbe to i ... | 2014 | 25005105 |
| genetic and mutational characterization of the small alarmone synthetase gene relv of vibrio cholerae. | in vibrio cholerae, the causative agent of cholera, products of three genes, rela, spot and relv, govern nutritional stress related stringent response (sr). sr in bacteria is critically regulated by two intracellular small molecules, guanosine 3'-diphosphate 5'-triphosphate (pppgpp) and guanosine 3',5'-bis(diphosphate) (ppgpp), collectively called (p)ppgpp or alarmone. evolution of relv is unique in v. cholerae because other gram-negative bacteria carry only rela and spot genes. recent reports s ... | 2014 | 24987103 |
| dimethyl sulphoxide and ca2+ stimulate assembly of vibrio cholerae ftsz. | we cloned, overexpressed and purified vibrio cholerae ftsz protein for the first time. we used several complementary techniques to probe and compare the comparative assembly properties of recombinant vibrio cholerae ftsz (vcftsz) and escherichia coli ftsz (ecftsz). we observed that vcftsz polymerized at a slower rate than ecftsz and interestingly its polymerization was highly dependent on the presence of ca(2+) ion. furthermore, dmso specifically modulated the polymerization of vcftsz, promoted ... | 2014 | 24970042 |
| influence of very short patch mismatch repair on sos inducing lesions after aminoglycoside treatment in escherichia coli. | low concentrations of aminoglycosides induce the sos response in vibrio cholerae but not in escherichia coli. in order to determine whether a specific factor present in e. coli prevents this induction, we developed a genetic screen where only sos inducing mutants are viable. we identified the vsr gene coding for the vsr protein of the very short patch mismatch repair (vspr) pathway. the effect of mismatch repair (mmr) mutants was also studied. we propose that lesions formed upon aminoglycoside t ... | 2014 | 24946128 |
| occurrence of vibrio and salmonella species in mussels (mytilus galloprovincialis) collected along the moroccan atlantic coast. | this study reports the occurrence of different vibrio and salmonella species in 52 samples of mytilus galloprovincialis collected from four sites along the atlantic coast between agadir and essaouira (anza, cap ghir, imssouane and essaouira). the level of escherichia coli (e. coli) was also determined to evaluate the degree of microbial pollution in the investigated areas. in this study three methods were used : afnor nf en iso 6579 v08-013 for salmonella spp., the provisional method routinely u ... | 2014 | 24936389 |
| interplay between genetic regulation of phosphate homeostasis and bacterial virulence. | bacterial pathogens, including those of humans, animals, and plants, encounter phosphate (pi)-limiting or pi-rich environments in the host, depending on the site of infection. the environmental pi-concentration results in modulation of expression of the pho regulon that allows bacteria to regulate phosphate assimilation pathways accordingly. in many cases, modulation of pho regulon expression also results in concomitant changes in virulence phenotypes. under pi-limiting conditions, bacteria use ... | 2014 | 24867401 |
| a single point mutation within the coding sequence of cholera toxin b subunit will increase its expression yield. | cholera toxin b subunit (ctb) has been extensively considered as an immunogenic and adjuvant protein, but its yield of expression is not satisfactory in many studies. the aim of this study was to compare the expression of native and mutant recombinant ctb (rctb) in pqe vector. | 2014 | 24842138 |
| faecal pollution loads in the wastewater effluents and receiving water bodies: a potential threat to the health of sedibeng and soshanguve communities, south africa. | the discharge of untreated or inadequately treated effluents has been identified among the activities responsible for the spread of a wide range of potentially infectious agents. the aim of this study was to determine whether inadequate treatment of wastewater and the faecal pollution load of effluents and receiving water bodies in sedibeng district and soshanguve peri-urban area of the tshwane metropolitan municipality could be a potential threat to the health of the surrounding communities. va ... | 2014 | 24838129 |
| cloning, expression, purification, crystallization and preliminary x-ray diffraction analysis of n-acetylmannosamine kinase from methicillin-resistant staphylococcus aureus. | n-acetylmannosamine kinase (ec 2.7.1.60) is involved in the catabolism of sialic acid for many bacterial pathogens implicated in human disease such as escherichia coli, staphylococcus aureus, vibrio cholerae and v. vulnificus. interestingly, some human commensals and bacterial pathogens can scavenge sialic acids from their surrounding environment and degrade them as a source of carbon, nitrogen and energy. this process requires a cluster of genes known as the `nan-nag cluster', which have proven ... | 2014 | 24817729 |
| reciprocal regulation of resistance-nodulation-division efflux systems and the cpx two-component system in vibrio cholerae. | the cpx two-component regulatory system has been shown in escherichia coli to alleviate stress caused by misfolded cell envelope proteins. the vibrio cholerae cpx system was previously found to respond to cues distinct from those in the e. coli system, suggesting that this system fulfills a different physiological role in the cholera pathogen. here, we used microarrays to identify genes that were regulated by the v. cholerae cpx system. our observations suggest that the activation of the v. chol ... | 2014 | 24799626 |
| the transcription factor mlc promotes vibrio cholerae biofilm formation through repression of phosphotransferase system components. | the phosphoenol phosphotransferase system (pts) is a multicomponent signal transduction cascade that regulates diverse aspects of bacterial cellular physiology in response to the availability of high-energy sugars in the environment. many pts components are repressed at the transcriptional level when the substrates they transport are not available. in escherichia coli, the transcription factor mlc (for makes large colonies) represses transcription of the genes encoding enzyme i (ei), histidine p ... | 2014 | 24769694 |
| structure of bacterial cytoplasmic chemoreceptor arrays and implications for chemotactic signaling. | most motile bacteria sense and respond to their environment through a transmembrane chemoreceptor array whose structure and function have been well-studied, but many species also contain an additional cluster of chemoreceptors in their cytoplasm. although the cytoplasmic cluster is essential for normal chemotaxis in some organisms, its structure and function remain unknown. here we use electron cryotomography to image the cytoplasmic chemoreceptor cluster in rhodobacter sphaeroides and vibrio ch ... | 2014 | 24668172 |
| characterization of the rstb2 protein, the dna-binding protein of ctxϕ phage from vibrio cholerae. | the low abundant protein rstb2, encoded in the rs2 region of ctxϕ, is essential for prophage formation. however, the only biochemical activity so far described is the single/double-stranded dna-binding capacity of that protein. in this paper, a recombinant rstb2 (rrstb2) protein was overexpressed in e. coli with a yield of 58.4 mg l(-1) in shaken cultures, lb broth. the protein, purified to homogeneity, showed an identity with rrstb2 by peptide mass fingerprinting. the apparent molecular weight ... | 2014 | 24643345 |
| memories of a virulent past. | studies on bacterial virulence and host-pathogen interactions usually rely on type strains isolated from human or veterinary populations. for instance, the el tor strain n16961 has been extensively used to characterize vibrio cholerae virulence, while e2348/69 is a default choice for studies on enteropathogenic e. coli interactions with host cells. subsequent to isolation, such strains are passaged under laboratory conditions in rich medium, and often genetically manipulated to induce specific m ... | 2014 | 24637797 |
| differential requirement for pbp1a and pbp1b in in vivo and in vitro fitness of vibrio cholerae. | we investigated the roles of the vibrio cholerae high-molecular-weight bifunctional penicillin binding proteins, pbp1a and pbp1b, in the fitness of this enteric pathogen. using a screen for synthetic lethality, we found that the v. cholerae pbp1a and pbp1b proteins, like their escherichia coli homologues, are each essential in the absence of the other and in the absence of the other's putative activator, the outer membrane lipoproteins lpoa and lpob, respectively. comparative analyses of v. chol ... | 2014 | 24614657 |
| ultra-sensitive, high-throughput detection of infectious diarrheal diseases by portable chemiluminescence imaging. | this paper describes a rapid, ultra-sensitive, and high-throughput pathogenic dna identification strategy for infectious diarrheal diseases diagnosis. this strategy is based on specific dna hybridization and horseradish-peroxidase-catalyzed chemiluminescence (cl) detection. probe dna strands are covalently immobilized on the aldehyde-group-modified slide and hybridized with biotin-modified target dna strands. horseradish-peroxidase (hrp) is then combined with the target dna via a biotin-streptav ... | 2014 | 24534578 |
| high number of diarrhoeal co-infections in travellers to benin, west africa. | travellers' diarrhoea (td) is the most frequent health problem among travellers to the tropics. using routine techniques, the aetiology mostly remains unresolved, whereas modern molecular methods enable reducing the number of equivocal cases considerably. while many studies address the aetiology of td in asian, central american and north african tourist resorts, only few focus on western africa. | 2014 | 24521079 |
| evaluation in mice of a conjugate vaccine for cholera made from vibrio cholerae o1 (ogawa) o-specific polysaccharide. | protective immunity against cholera is serogroup specific. serogroup specificity in vibrio cholerae is determined by the o-specific polysaccharide (osp) of lipopolysaccharide (lps). generally, polysaccharides are poorly immunogenic, especially in young children. | 2014 | 24516685 |
| domain isolation, expression, purification and proteolytic activity of the metalloprotease prtv from vibrio cholerae. | the metalloprotease prtv from vibrio cholerae serves an important function for the bacteria's ability to invade the mammalian host cell. the protein belongs to the family of m6 proteases, with a characteristic zinc ion in the catalytic active site. prtv constitutes a 918 amino acids (102 kda) multidomain pre-pro-protein that so far has only been expressed in v. cholerae. structural studies require high amounts of soluble protein with high purity. previous attempts for recombinant expression have ... | 2014 | 24492010 |
| identification of a membrane-bound transcriptional regulator that links chitin and natural competence in vibrio cholerae. | vibrio cholerae is naturally competent when grown on chitin. it is known that expression of the major regulator of competence, tfox, is controlled by chitin; however, the molecular mechanisms underlying this requirement for chitin have remained unclear. in the present study, we identify and characterize a membrane-bound transcriptional regulator that positively regulates the small rna (srna) tfor, which posttranscriptionally enhances tfox translation. we show that this regulation of the tfor pro ... | 2014 | 24473132 |
| 193 nm ultraviolet photodissociation mass spectrometry for the structural elucidation of lipid a compounds in complex mixtures. | here we implement ultraviolet photodissociation (uvpd) in an online liquid chromatographic tandem mass spectrometry (ms/ms) strategy to support analysis of complex mixtures of lipid a combinatorially modified during development of vaccine adjuvants. uvpd mass spectrometry at 193 nm was utilized to characterize the structures and fragment ion types of lipid a from escherichia coli, vibrio cholerae, and pseudomonas aeruginosa using an orbitrap mass spectrometer. the fragment ions generated by uvpd ... | 2014 | 24446701 |
| importance of cholera and other etiologies of acute diarrhea in post-earthquake port-au-prince, haiti. | we estimated the proportion of diarrhea attributable to cholera and other pathogens during the rainy and dry seasons in patients seen in two urban health settings: a cholera treatment center (ctc) and oral rehydration points (orps). during april 1, 2011-november 30, 2012, stool samples were collected from 1,206 of 10,845 patients who came to the gheskio ctc or to the community orps with acute diarrhea, cultured for vibrio cholerae, and tested by multiplex polymerase reaction. vibrio cholerae was ... | 2014 | 24445205 |
| combined effect of lime (citrus aurantitolia) and drying on reducing bacteria of public health significance in edible oyster (crassostrea madrasensis). | combined effect of lime and drying on bacteria of public health significance in edible oyster (crassostrea madrasensis) from munambam coastal belt (kerala, india) were studied (without depuration). samples were examined for total plate count (tpc), staphylococcus aureus (hygiene indicator), total coliforms, faecal coliforms, escherichia coli, (faecal indicator) faecal streptococci (faecal indicator), salmonella, vibrio cholera and listeria monocytogenes. the fresh oyster meat though did not conf ... | 2013 | 24425910 |
| pvv3, a new shuttle vector for gene expression in vibrio vulnificus. | an efficient electroporation procedure for vibrio vulnificus was designed using the new cloning vector pvv3 (3,107 bp). transformation efficiencies up to 2 × 10(6) transformants per μg dna were achieved. the vector stably replicated in both v. vulnificus and escherichia coli and was also successfully introduced into vibrio parahaemolyticus and vibrio cholerae. to demonstrate the suitability of the vector for molecular cloning, the green fluorescent protein (gfp) gene and the vvhba hemolysin oper ... | 2014 | 24362421 |
| localization-controlled specificity of fad:threonine flavin transferases in klebsiella pneumoniae and its implications for the mechanism of na(+)-translocating nadh:quinone oxidoreductase. | the klebsiella pneumoniae genome contains genes for two putative flavin transferase enzymes (apbe1 and apbe2) that add fmn to protein thr residues. apbe1, but not apbe2, has a periplasm-addressing signal sequence. the genome also contains genes for three target proteins with the dxx(s/t)gat flavinylation motif: two subunits of na(+)-translocating nadh:quinone oxidoreductase (na(+)-nqr), and a 99.5kda protein, kpk_2907, with a previously unknown function. we show here that kpk_2907 is an active c ... | 2014 | 24361839 |
| the c-terminal cytoplasmic portion of the nhap2 cation-proton antiporter from vibrio cholerae affects its activity and substrate affinity. | in this work, we report the phenotypic and biochemical effects of deleting the c-terminal cytoplasmic portion of the nhap2 cation/proton antiporter from vibrio cholerae. while the deletion changed neither the expression nor targeting of the vc-nhap2 in an antiporter-less escherichia coli strain, it resulted in a changed sensitivity of the host to sodium ions at neutral ph, indicating an altered na(+) transport through the truncated variant. when assayed in inside-out sub-bacterial vesicles, the ... | 2014 | 24347178 |
| etiological diversity of diarrhoeal disease in bangladesh. | this study compared the diversity of common diarrhoeal pathogens and antimicrobial susceptibility in four hospitals in bangladesh. | 2013 | 24334935 |
| development of an immunochromatographic test strip for detection of cholera toxin. | because cholera toxin (ct) is responsible for most of the symptoms induced by vibrio cholerae infection, detection of ct is critical for diagnosis of the disease. in this study, we constructed an immunochromatographic test strip for detection of ct (ct-ic) with polyclonal antibodies developed against purified recombinant whole ct protein. the detection limit of the ct-ic was 10 ng/ml of purified recombinant ct, and it could detect the ct in culture supernatant of all 15 toxigenic v. cholerae iso ... | 2013 | 24308002 |
| cloning and identification of a novel nhad-type na+/h+ antiporter from metagenomic dna of the halophilic bacteria in soil samples around daban salt lake. | in this study, metagenomic dna was screened for the na(+)/h(+) antiporter gene from the halophilic bacteria in daban salt lake by selection in escherichia coli knabc lacking three major na(+)/h(+) antiporters. one gene designated as hb_nhad encoding a novel nhad-type na(+)/h(+) antiporter was finally cloned. the presence of hb_nhad conferred tolerance of e. coli knabc to up to 0.5 m nacl and 0.2 m licl, and an alkaline ph. hb_nhad has the highest identity (70.6%) with a putative nhad-type na(+)/ ... | 2014 | 24297704 |
| an improved method for surface immobilisation of rna: application to small non-coding rna-mrna pairing. | characterisation of rna and its intermolecular interactions is increasing in importance as the inventory of known rna functions continues to expand. rna-rna interactions are central to post-transcriptional gene regulation mechanisms in bacteria, and the interactions of bacterial small non-coding rnas (srnas) with their mrna targets are the subject of much current research. the technology of surface plasmon resonance (spr) is an attractive approach to studying these interactions since it is highl ... | 2013 | 24244437 |
| regulation of natural competence by the orphan two-component system sensor kinase chis involves a non-canonical transmembrane regulator in vibrio cholerae. | in vibrio cholerae, 41 chitin-inducible genes, including the genes involved in natural competence for dna uptake, are governed by the orphan two-component system (tcs) sensor kinase chis. however, the mechanism by which chis controls the expression of these genes is currently unknown. here, we report the involvement of a novel transcription factor termed 'tfos' in this process. tfos is a transmembrane protein that contains a large periplasmic domain and a cytoplasmic arac-type dna-binding domain ... | 2014 | 24236404 |
| antibacterial and antidiarrheal activities of plant products against enterotoxinogenic escherichia coli. | enterotoxigenic escherichia coli (etec) produces two types of enterotoxins: heat-labile (lt) and heat-stable (sta and stb). these molecules are involved in the induction of secretory diarrhea in animals including humans. this condition is currently treated using a fluid replacement therapy and antibiotics. this treatment is often not available to people in developing countries, and several die from the condition provoke by etec. over the years, plants and plant extracts have been use as traditio ... | 2013 | 24212181 |
| rapid protocol for preparation of electrocompetent escherichia coli and vibrio cholerae. | electroporation has become a widely used method for rapidly and efficiently introducing foreign dna into a wide range of cells. electrotransformation has become the method of choice for introducing dna into prokaryotes that are not naturally competent. electroporation is a rapid, efficient, and streamlined transformation method that, in addition to purified dna and competent bacteria, requires commercially available gene pulse controller and cuvettes. in contrast to the pulsing step, preparation ... | 2013 | 24146001 |
| 5 year efficacy of a bivalent killed whole-cell oral cholera vaccine in kolkata, india: a cluster-randomised, double-blind, placebo-controlled trial. | efficacy and safety of a two-dose regimen of bivalent killed whole-cell oral cholera vaccine (shantha biotechnics, hyderabad, india) to 3 years is established, but long-term efficacy is not. we aimed to assess protective efficacy up to 5 years in a slum area of kolkata, india. | 2013 | 24140390 |
| antibacterial and antiviral evaluation of sulfonoquinovosyldiacylglyceride: a glycolipid isolated from azadirachta indica leaves. | assessment of antibacterial as well as antiherpes virus activity of sulfonoquinovosyldiacylglyceride (sqdg), a glycolipid, isolated from the leaves of azadirachta indica has been described. antimicrobial activity was evaluated against gram-positive, gram-negative bacteria and herpes simplex virus. sqdg showed significant inhibitory activity against salmonella typhi and two isolates of shigella dysenteriae with mic values 32 μg ml(-1) , while three isolates of salm. typhi, escherichia coli and vi ... | 2014 | 24118020 |
| structure and secretion of cofj, a putative colonization factor of enterotoxigenic escherichia coli. | enterotoxigenic escherichia coli (etec) colonize the human gut, causing severe cholera-like diarrhoea. etec utilize a diverse array of pili and fimbriae for host colonization, including the type ivb pilus cfa/iii. the cfa/iii pilus machinery is encoded on the cof operon, which is similar in gene sequence and synteny to the tcp operon that encodes another type ivb pilus, the vibrio cholerae toxin co-regulated pilus (tcp). both pilus operons possess a syntenic gene encoding a protein of unknown fu ... | 2013 | 24106767 |
| the mosaic accessory gene structures of the sxt/r391-like integrative and conjugative elements derived from vibrio spp. isolated from aquatic products and environment in the yangtze river estuary, china. | the emergence, resurgence and spread of human food-borne pathogenic vibrios are one of the major contributors to disease burden and mortality particularly in developing countries with disputable sanitary conditions. previous research on pathogenic vibrio cholerae and vibrio parahaemolitycus derived from clinical samples has proposed links between acquisition of virulence and multiple drug resistance traits and intercellular transmissibility of mobile genetic elements in the environment. to date, ... | 2013 | 24074349 |
| grape extracts inhibit multiple events in the cell biology of cholera intoxication. | vibrio cholerae produces cholera toxin (ct), an ab5 protein toxin that is primarily responsible for the profuse watery diarrhea of cholera. ct is secreted into the extracellular milieu, but the toxin attacks its gsα target within the cytosol of a host cell. thus, ct must cross a cellular membrane barrier in order to function. this event only occurs after the toxin travels by retrograde vesicular transport from the cell surface to the endoplasmic reticulum (er). the catalytic a1 polypeptide then ... | 2013 | 24039929 |
| next-generation anchor based phylogeny (nexabp): constructing phylogeny from next-generation sequencing data. | whole genome sequences are ideally suited for deriving evolutionary relationship among organisms. with the availability of next generation sequencing (ngs) datasets in an unprecedented scale, it will be highly desirable if phylogenetic analysis can be carried out using short read ngs data. we described here an anchor based approach nexabp for phylogenetic construction of closely related strains/isolates from ngs data. this approach can be used even in the absence of a fully assembled reference g ... | 2013 | 24022334 |
| isolation of vibrio cholerae and other enteric microbiota from patients with suspected cholera during the 2009 outbreak in madang province, papua new guinea. | when cholera was first detected in papua new guinea (png) in mid-2009, national diagnostic capacity faced many challenges. this was in part due to the non-endemic status of the outbreak, resulting in few local staff experienced in vibrio cholerae detection and poor access to the required consumables. the png institute of medical research conducted culture on specimens from suspected cholera patients in madang province, with presumptive v. cholerae isolates sent to goroka for confirmation. of 98 ... | 2015 | 26288927 |
| [studies on the mode of action of bacterial ab5 toxins]. | bacterial ab5 toxins are proteins, produced by pathogenic bacteria including of vibrio cholerae, shigella dysenteriae, and enterohaemorrhagic escherichia coli, which are usually released into the extracellular medium and cause disease by killing or altering the metabolism of target eukaryotic cells. the toxins are usually composed of one a subunit (a toxic domain) and five b subunits (a receptor-binding domain). this article overviews the characteristics and mode of actions of ab5 toxins includi ... | 2013 | 23985936 |
| genetic systems for monitoring interactions of transmembrane domains in bacterial membranes. | in recent years several systems have been developed to study interactions of tm domains within the inner membrane of the gram-negative bacterium escherichia coli. mostly, a transmembrane domain of interest is fused to a soluble dna-binding domain, which dimerizes in e. coli cytoplasm after interactions of the transmembrane domains. the dimeric dna-binding domain subsequently binds to a promoter/operator region and thereby activates or represses a reporter gene. in 1996 the first bacterial system ... | 2013 | 23975772 |
| conformational freedom in tight binding enzymatic transition-state analogues. | transition-state analogues of bacterial 5'-methylthioadenosine/s-adenosylhomocysteine nucleosidases (mtans) disrupt quorum-sensing pathways in escherichia coli and vibrio cholerae, demonstrating the potential to limit pathogenicity without placing bacteria under intense selective pressure that leads to antibiotic resistance. despite the similarity of the crystal structures of e. coli mtan (ecmtan) and v. cholerae mtan (vcmtan) bound to dadme-immucillin-a transition-state (ts) analogues, ecmtan d ... | 2013 | 23895500 |
| virulence profile: yoshikazu nishikawa. | | 2013 | 23863447 |
| selected insights from application of whole-genome sequencing for outbreak investigations. | the advent of high-throughput whole-genome sequencing has the potential to revolutionize the conduct of outbreak investigation. because of its ultimate resolution power for differentiating between closely related pathogen strains, whole-genome sequencing could augment the traditional epidemiologic investigations of infectious disease outbreaks. | 2013 | 23856896 |
| the mechanoelectrical response of the cytoplasmic membrane of vibrio cholerae. | persistence of vibrio cholerae in waters of fluctuating salinity relies on the capacity of this facultative enteric pathogen to adapt to varying osmotic conditions. in an event of osmotic downshift, osmolytes accumulated inside the bacterium can be quickly released through tension-activated channels. with the newly established procedure of giant spheroplast preparation from v. cholerae, we performed the first patch-clamp characterization of its cytoplasmic membrane and compared tension-activated ... | 2013 | 23797422 |
| catalytic preference of salmonella typhimurium lt2 sialidase for n-acetylneuraminic acid residues over n-glycolylneuraminic acid residues. | in a comparison of sialidase activities toward n-acetylneuraminic acid (neu5ac) and n-glycolylneuraminic acid (neu5gc), we found that salmonella typhimurium lt2 sialidase (stsa) hardly cleaved 4-methylumbelliferyl neu5gc (4mu-neu5gc). the k cat/k m value of stsa for 4mu-neu5gc was found to be 110 times lower than that for 4-methylumbelliferyl neu5ac (4mu-neu5ac). additionally, stsa had remarkably weak ability to cleave α2-3-linked-neu5gc contained in gangliosides and equine erythrocytes. in sili ... | 2013 | 23772399 |
| detection of escherichia coli, salmonella species, and vibrio cholerae in tap water and bottled drinking water in isfahan, iran. | the quality of drinking water has an important role in human infection and disease. this study was aimed at comparing polymerase chain reaction and culture in detecting escherichia coli, salmonella species and vibrio cholera in tape water and bottled drinking water in various seasons in isfahan province, iran. | 2013 | 23742181 |
| a comparative proteomic analysis of vibrio cholerae o1 wild-type cells versus a phob mutant showed that the phob/phor system is required for full growth and rpos expression under inorganic phosphate abundance. | phob/phor is a two-component system originally described as involved in inorganic phosphate (pi) transport and metabolism under pi limitation. in order to disclose other roles of this system, a proteomic analysis of vibrio cholerae 569bsr and its phob/phor mutant under high pi levels was performed. most of the proteins downregulated by the mutant have roles in energy production and conversion and in amino acid transport and metabolism. in contrast, the phob/phor mutant upregulated genes mainly i ... | 2013 | 23665147 |
| a quantitative polymerase chain reaction assay for rapid detection of 9 pathogens directly from stools of travelers with diarrhea. | every year, 80 million tourists traveling to tropical and subtropical areas contract traveler's diarrhea (td). forty percent to 80% of cases are caused by bacteria, yet clinical diagnostic tests are available to identify only a few of the strains that cause td. we aimed to develop a quantitative polymerase chain reaction (qpcr) assay to identify all major pathogens in stool samples. | 2013 | 23639597 |
| review of the inhibition of biological activities of food-related selected toxins by natural compounds. | there is a need to develop food-compatible conditions to alter the structures of fungal, bacterial, and plant toxins, thus transforming toxins to nontoxic molecules. the term 'chemical genetics' has been used to describe this approach. this overview attempts to survey and consolidate the widely scattered literature on the inhibition by natural compounds and plant extracts of the biological (toxicological) activity of the following food-related toxins: aflatoxin b1, fumonisins, and ochratoxin a p ... | 2013 | 23612750 |
| the genome of vp3, a t7-like phage used for the typing of vibrio cholerae. | the bacteriophage vp3 is used in a phage-biotyping scheme as one of the typing phages of vibrio cholerae o1 biotype el tor strains. here, we have sequenced and analyzed its genome. the genome consists of 39,481 bp with an overall g + c content of 42.6 %. fifty-two open reading frames (orfs) were predicted. within the genome, 17 highly conserved phage promoters and 6 rho-independent terminators were predicted. when assessed with rluc as a reporter gene, 12 of 16 cloned vp3 promoters showed activi ... | 2013 | 23543142 |
| a visual assay to monitor t6ss-mediated bacterial competition. | type vi secretion systems (t6sss) are molecular nanomachines allowing gram-negative bacteria to transport and inject proteins into a wide variety of target cells(1,2). the t6ss is composed of 13 core components and displays structural similarities with the tail-tube of bacteriophages(3). the phage uses a tube and a puncturing device to penetrate the cell envelope of target bacteria and inject dna. it is proposed that the t6ss is an inverted bacteriophage device creating a specific path in the ba ... | 2013 | 23542679 |
| β-lactam antibiotics promote bacterial mutagenesis via an rpos-mediated reduction in replication fidelity. | regardless of their targets and modes of action, subinhibitory concentrations of antibiotics can have an impact on cell physiology and trigger a large variety of cellular responses in different bacterial species. subinhibitory concentrations of β-lactam antibiotics cause reactive oxygen species production and induce poliv-dependent mutagenesis in escherichia coli. here we show that subinhibitory concentrations of β-lactam antibiotics induce the rpos regulon. rpos-regulon induction is required fo ... | 2013 | 23511474 |
| comparison of two recombinant systems for expression of cholera toxin b subunit from vibrio cholerae. | the aim of this study was to assess the production of recombinant cholera toxin b subunit (rctb) protein in two different expression systems (pae_ctxb and pqe_ctxb constructs) in escherichia coli bl21 (de3). | 2013 | 23508422 |
| role of a teha homolog in vibrio cholerae c6706 antibiotic resistance and intestinal colonization. | vibrio cholerae is the causative agent of the devastating diarrheal disease cholera. a number of regulatory pathways are involved in v. cholerae pathogenesis and antibiotic resistance. for example, there are over 40 lysr-family proteins in the v. cholerae genome, but most of their functions are unknown. in this study, we examine the role of vc2323 (tehavc) and its divergently transcribed lysr-family regulator vc2324 (tehrvc) in v. cholerae pathogenesis. we found that in v. cholerae c6706, the ex ... | 2013 | 23461522 |
| clinical isolates of vibrio cholerae o1 el tor ogawa of 2009 from kolkata, india: preponderance of sxt element and presence of haitian ctxb variant. | increase in the number of multidrug resistant pathogens and the accompanied rise in case fatality rates has hampered the treatment of many infectious diseases including cholera. unraveling the mechanisms responsible for multidrug resistance in the clinical isolates of vibrio cholerae would help in understanding evolution of these pathogenic bacteria and their epidemic potential. this study was carried out to identify genetic factors responsible for multiple drug resistance in clinical isolates o ... | 2013 | 23431378 |
| biochemical properties of a new α-carbonic anhydrase from the human pathogenic bacterium, vibrio cholerae. | abstract vibrio cholerae, a gram-negative bacterium, is the causative agent of cholera and colonizes the upper small intestine where sodium bicarbonate is present at a high concentration. sodium bicarbonate is a potential inducer of virulence gene expression. bacteria can increase cytosolic bicarbonate levels through the existence of transporter family proteins or through the action of metalloenzymes, called carbonic anhydrases (cas, ec 4.2.1.1). vibrio cholerae, lacking of transporter proteins ... | 2014 | 23321008 |