Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| microbial growth and quorum sensing antagonist activities of herbal plants extracts. | antimicrobial and antiquorum sensing (aqs) activities of fourteen ethanolic extracts of different parts of eight plants were screened against four gram-positive, five gram-negative bacteria and four fungi. depending on the plant part extract used and the test microorganism, variable activities were recorded at 3 mg per disc. among the grampositive bacteria tested, for example, activities of laurus nobilis bark extract ranged between a 9.5 mm inhibition zone against bacillus subtilis up to a 25 m ... | 2009 | 19783935 |
| efficient synthesis and evaluation of quorum-sensing modulators using small molecule macroarrays. | a method for the synthesis of small molecule macroarrays of n-acylated l-homoserine lactones (ahls) is reported. a focused library of ahls was constructed, and the macroarray platform was found to be compatible with both solution and agar-overlay assays using quorum-sensing (qs) reporter strains. several qs antagonists were discovered and serve to showcase the macroarray as a straightforward technique for qs research. | 2009 | 19743816 |
| culturable heterotrophic bacteria in seawater and mytilus galloprovincialis from a mediterranean area (northern ionian sea-italy). | although mar piccolo of taranto (ionian sea, italy) is one of the most important mytilus galloprovincialis farming areas, data concerning the natural bacterial microbiota of these mussels and their surrounding environment are still scant. this study was carried out seasonally, throughout a year, to determine culturable heterotrophic bacteria both in the water and mussels samples collected at three sampling sites in the northern ionian sea: s. vito, lido gandoli and lido silvana. culturable heter ... | 2009 | 18301997 |
| species distribution and antimicrobial susceptibility of gram-negative aerobic bacteria in hospitalized cancer patients. | nosocomial infections pose significant threats to hospitalized patients, especially the immunocompromised ones, such as cancer patients. | 2009 | 19228413 |
| chromobacterium violaceum endocarditis and hepatic abscesses treated successfully with meropenem and ciprofloxacin. | chromobacterium violaceum infection is uncommon but potentially fatal, with a clinical picture similar to melioidosis but with different antibiotic sensitivities and treatment. this infection can involve any organ, but we believe this is the first reported case of c. violaceum endocarditis. | 2009 | 19351314 |
| an fad-dependent pyridine nucleotide-disulfide oxidoreductase is involved in disulfide bond formation in fk228 anticancer depsipeptide. | disulfide bonds are rare in bacterial natural products, and the mechanism of disulfide bond formation in those products is unknown. here we characterize a gene and its product critical for a disulfide bond formation in fk228 anticancer depsipeptide in chromobacterium violaceum. deletion of deph drastically reduced fk228 production, whereas complementation of the deph-deletion mutant with a copy of deph on a medium copy-number plasmid not only fully restored the fk228 production but also signific ... | 2009 | 19549597 |
| synthesis, nematicidal and antimicrobial properties of bis-[4-methoxy-3-[3-(4-fluorophenyl)-6-(4-methylphenyl)-2(aryl)-tetrahydro-2h-pyrazolo[3,4-d]thiazol-5-yl]phenyl]methanes. | a new series of bis-[4-methoxy-3-[3-(4-fluorophenyl)-6-(4-methylphenyl)-2-(aryl)-3,3a,5,6-tetrahydro-2h-pyrazolo[3,4-d][1,3]thiazol-5-yl]phenyl]methanes 6a-r was synthesized by the reaction of arylidine derivative of methylene-bis-thiazolidinones 5a-c with aryl/alkyl hydrazines. chemical structures of all the new compounds were established by ir, (1)h-nmr, (13)c-nmr, ms and elemental data. the compounds 6a-r were evaluated for their nematicidal activity against ditylenchus myceliophagus and caen ... | 2009 | 19571412 |
| cloning, sequence analysis, and expression of a gene encoding chromobacterium sp. ds-1 cholesterol oxidase. | chromobacterium sp. strain ds-1 produces an extracellular cholesterol oxidase that is very stable at high temperatures and in the presence of organic solvents and detergents. in this study, we cloned and sequenced the structural gene encoding the cholesterol oxidase. the primary translation product was predicted to be 584 amino acid residues. the mature product is composed of 540 amino acid residues. the amino acid sequence of the product showed significant similarity (53-62%) to the cholesterol ... | 2009 | 19015844 |
| fatal chromobacterium violaceum septicaemia in northern laos, a modified oxidase test and post-mortem forensic family g6pd analysis. | chromobacterium violaceum is a gram negative facultative anaerobic bacillus, found in soil and stagnant water, that usually has a violet pigmented appearance on agar culture. it is rarely described as a human pathogen, mostly from tropical and subtropical areas. | 2009 | 19640274 |
| violacein extracted from chromobacterium violaceum inhibits plasmodium growth in vitro and in vivo. | violacein is a violet pigment extracted from the gram-negative bacterium chromobacterium violaceum. it presents bactericidal, tumoricidal, trypanocidal, and antileishmanial activities. we show that micromolar concentrations efficiently killed chloroquine-sensitive and -resistant plasmodium falciparum strains in vitro; inhibited parasitemia in vivo, even after parasite establishment; and protected plasmodium chabaudi chabaudi-infected mice from a lethal challenge. | 2009 | 19273690 |
| anti-diarrhoeal and ulcer-protective effects of violacein isolated from chromobacterium violaceum in wistar rats. | violacein was isolated from chromobacterium violaceum, a soil gram-negative bacterium collected from the forest water body soil sample from kolli hills of tamil nadu, india. in the present study the anti-diarrhoeal and ulcer-protective properties of violacein were investigated in wistar rats using castor oil, magnesium sulphate and ethanol. the intestinal transit in rats was significantly (p < 0.001) reduced and gastric emptying was delayed; 40 mg/kg of violacein elicited a greater anti-motility ... | 2009 | 19709325 |
| quorum sensing inhibition activity of garlic extract and p-coumaric acid. | the goal of this work was to investigate the influence of dmso, garlic extract and p-coumaric acid on bacterial quorum sensing (qs). | 2009 | 19709367 |
| septicemia in a neonatal calf associated with chromobacterium violaceum. | chromobacterium violaceum infections are highly fatal and rarely reported in domestic animals. this report describes a fatal case of c. violaceum septicemia in a 7-day-old female beef calf. the calf had necrosuppurative omphalophlebitis, necrotizing interstitial pneumonia, necrosuppurative hepatitis and splenitis, anterior uveitis with hypopyon, suppurative polyarthritis, and disseminated hemorrhagic meningitis with multifocal necrotizing encephalitis. histologically, clusters of gram-negative b ... | 2009 | 19112118 |
| a probable aculeacin a acylase from the ralstonia solanacearum gmi1000 is n-acyl-homoserine lactone acylase with quorum-quenching activity. | the infection and virulence functions of diverse plant and animal pathogens that possess quorum sensing systems are regulated by n-acylhomoserine lactones (ahls) acting as signal molecules. ahl-acylase is a quorum quenching enzyme and degrades ahls by removing the fatty acid side chain from the homoserine lactone ring of ahls. this blocks ahl accumulation and pathogenic phenotypes in quorum sensing bacteria. | 2009 | 19426552 |
| enhanced production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer with manipulated variables and its properties. | cupriavidus sp. usmaa1020, a local isolate was able to biosynthesis poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [p(3hb-co-4hb)] copolymer with various 4hb precursors as the sole carbon source. manipulation of the culture conditions such as cell concentration, phosphate ratio and culture aeration significantly affected the synthesis of p(3hb-co-4hb) copolymer and 4hb composition. p(3hb-co-4hb) copolymer with 4hb compositions ranging from 23 to 75 mol% 4hb with various mechanical and thermal prop ... | 2009 | 19189144 |
| polyhydroxyalkanoate (pha) production using waste vegetable oil by pseudomonas sp. strain dr2. | to produce polyhydroxyalkanoate (pha) from inexpensive substrates by bacteria, vegetable-oil-degrading bacteria were isolated from a rice field using enrichment cultivation. the isolated pseudomonas sp. strain dr2 showed clear orange or red spots of accumulated pha granules when grown on phosphate and nitrogen limited medium containing vegetable oil as the sole carbon source and stained with nile blue a. up to 37.34% (w/w) of intracellular pha was produced from corn oil, which consisted of three ... | 2008 | 18756101 |
| chromobacterium violaceum infection in a provincial hospital in sri lanka. | 2008 | 19189802 | |
| kinetic isotope effects on aromatic and benzylic hydroxylation by chromobacterium violaceum phenylalanine hydroxylase as probes of chemical mechanism and reactivity. | phenylalanine hydroxylase from chromobacterium violaceum (cvpheh) is a non-heme iron monooxygenase that catalyzes the hydroxylation of phenylalanine to tyrosine. in this study, we used deuterium kinetic isotope effects to probe the chemical mechanisms of aromatic and benzylic hydroxylation to compare the reactivities of bacterial and eukaryotic aromatic amino acid hydroxylases. the (d) k cat value for the reaction of cvpheh with [(2)h 5]phenylalanine is 1.2 with 6-methyltetrahydropterin and 1.4 ... | 2008 | 18817418 |
| cellulose biosynthesis by the beta-proteobacterium, chromobacterium violaceum. | the chromobacterium violaceum atcc 12472 genome was sequenced by the brazilian national genome project consortium. previous annotation reported the presence of cellulose biosynthesis genes in that genome. analysis of these genes showed that, as observed in other bacteria, they are organized in two operons. in the present work, experimental evidences of the presence of cellulose in the extracellular matrix of the biofilm produced by c. violaceum in static cultures are shown. biofilm samples were ... | 2008 | 18820969 |
| diversity of chromobacterium violaceum isolates from aquatic environments of state of pará, brazilian amazon. | the present study intended to characterize the phenotypic and genetic diversity of brazilian isolates of chromobacterium violaceum from aquatic environments within the amazon region. nineteen isolates showed morphological properties of c. violaceum and the majority grew at 44 degrees c. low temperatures, in contrast, showed to be inhibitory to their growth, as eleven isolates did not grow at 10 degrees c and nine did not produce pigmentation, clearly indicating an inhibition of their metabolism. ... | 2008 | 19057818 |
| successful treatment of chromobacterium violaceum sepsis in south africa. | chromobacterium violaceum sepsis is extremely rare and usually fatal. a very few cases of c. violaceum infection have been reported from africa, but never from south africa. as far as could be ascertained, this infection has never been reported in a patient with leukaemia. we describe what we believe to be the first such case of c. violaceum sepsis, in a 16-year-old female patient with acute biphenotypic leukaemia, which developed during the neutropenic phase after intensive chemotherapy. the in ... | 2008 | 18809561 |
| rapid hydrolysis of quorum-sensing molecules in the gut of lepidopteran larvae. | microorganisms compete for nutrients and living space in the gut of plant-feeding insect larvae, such as spodoptera spp. their physiological activities and their organization are generally controlled or synchronised by "autoinducers", such as n-acylhomoserinelactones (ahls). due to the strongly alkaline milieu in the insect gut, the lactone ring of ahls is rapidly and spontaneously opened. further degradation to the inactive components homoserine and the acyl moiety is then achieved by a microbi ... | 2008 | 18642255 |
| fatal wound infection caused by chromobacterium violaceum in ho chi minh city, vietnam. | chromobacterium violaceum is a proteobacterium found in soil and water in tropical regions which rarely causes infection in humans. here, we report a fatal bacteremia caused by chromobacterium violaceum in vietnam. we describe a number of clinical, microbiological, and molecular aspects associated with this bacterial infection. | 2008 | 18799697 |
| inhibition of bacterial quorum sensing-regulated behaviors by tremella fuciformis extract. | quorum sensing (qs), or the control of gene expression in response to cell density, is used by both gram-negative and gram-positive bacteria to regulate a variety of physiological functions. increasing evidence implies that certain eukaryotes produce qs-inhibitory compounds. in this work, we tested tremella fuciformis for their ability to inhibit qs-regulated behaviors. t. fuciformis fruiting bodies were dried and extracted using 75% (v/v) aqueous methanol. the crude extract was redissolved in a ... | 2008 | 18661179 |
| pseudogulbenkiania subflava gen. nov., sp. nov., isolated from a cold spring. | a yellow-coloured bacterial strain, designated bp-5(t), was isolated from a water sample of a cold spring located in the hsinchu area of northern taiwan. cells of the strain were gram-negative, non-spore-forming rods with a polar flagellum. the isolate was able to grow at 15-42 degrees c, 0-1 % nacl and ph 6-8. the predominant fatty acids were summed feature 3 (c(16 : 1)omega7c and/or iso-c(15 : 0) 2-oh), c(16 : 0) and c(18 : 1)omega7c. the major respiratory quinone was ubiquinone 8. the dna g+c ... | 2008 | 18842860 |
| prevalence of bacterial pathogens and their anti-microbial resistance in tilapia and their pond water in trinidad. | in trinidad, tilapia (oreonchromis spp.) is one of the most important fresh water food fish and the number of farms has been increasing annually. a study was conducted in the local tilapia industry to determine the microbial quality of pond water, prevalence of bacterial pathogens and their anti-microbial resistance using the disk diffusion method. seventy-five apparently healthy fish and 15 pond water samples from three of the four commercial tilapia fish farms in the country were processed. th ... | 2008 | 18387142 |
| gene expression of the arsenic resistance operon in chromobacterium violaceum atcc 12472. | chromobacterium violaceum atcc 12472 presents an arsrcb-type operon, which is involved in arsenic resistance. the regulating protein of this resistance system (arsr) does not have the small conserved site (elcvdcl) to link to the metalloid, as observed in escherichia coli, and is thus considered to be an atypical arsr protein, like that observed in acidithiobacillus ferrooxidans. in the present study, the gene expression profile of the ars operon under induction at different concentrations of ar ... | 2008 | 18388983 |
| chromobacterium haemolyticum sp. nov., a strongly haemolytic species. | a gram-negative bacterium, strain mda0585(t), isolated from a sputum culture, was characterized by a polyphasic approach. the 16s rrna gene and a conserved portion of the dna gyrase a gene were sequenced and analysed phylogenetically. strain mda0585(t) showed the closest relationships with chromobacterium violaceum atcc 12472(t) and chromobacterium subtsugae praa4-1(t) (96.1 % and 96.3 % 16s rrna gene sequence similarity, respectively). the cellular fatty acids of strain mda0585(t) consisted mai ... | 2008 | 18523185 |
| chromobacterium aquaticum sp. nov., isolated from spring water samples. | strain cc-seya-1t, a motile, gram-negative, non-violet-pigmented bacterium, was isolated on nutrient agar from spring-water samples collected from yang-ming mountain, taipei county, taiwan. 16s rrna gene sequence studies showed that the strain clustered with chromobacterium violaceum (96.8 % similarity) and chromobacterium subtsugae (96.5 % similarity), followed by aquitalea magnusonii (95.8 % similarity). the fatty acid profile was slightly different from those reported for c. violaceum, c. sub ... | 2008 | 18398186 |
| recurrent chromobacterium violaceum infection in a patient with chronic granulomatous disease. | we report a rare case of recurrent infection of chromobacterium violaceum in an immunocompromised patient. despite the high mortality rate associated with this infection as reported in the literature, this patient survived three episodes of recurrent infection. we believe that with high clinical suspicion, prompt treatment and appropriate antimicrobial agents, it is possible for clinicians to treat this infection effectively and reduce the mortality rate. | 2008 | 19385503 |
| amphibian chemical defense: antifungal metabolites of the microsymbiont janthinobacterium lividum on the salamander plethodon cinereus. | disease has spurred declines in global amphibian populations. in particular, the fungal pathogen batrachochytrium dendrobatidis has decimated amphibian diversity in some areas unaffected by habitat loss. however, there is little evidence to explain how some amphibian species persist despite infection or even clear the pathogen beyond detection. one hypothesis is that certain bacterial symbionts on the skin of amphibians inhibit the growth of the pathogen. an antifungal strain of janthinobacteriu ... | 2008 | 18949519 |
| improved activity of enzymes in mixed cationic reverse micelles with imidazolium-based surfactants. | this work reports the significant enhancement in performance of interfacially active enzymes, chromobacterium viscosum (cv) lipase and horseradish peroxidase (hrp) in mixed reverse micelles of cetyltrimethylammonium bromide (ctab) and imidazolium-based amphiphiles having varying tail lengths. lipase activity in these mixed systems was always higher than that in the individual cationic reverse micelles of ctab or any imidazolium surfactant, highest being observed in the mixed system of ctab (50 m ... | 2008 | 18067868 |
| bacteria flora and heavy metals in cultivated oysters crassostrea iredalei of setiu wetland, east coast peninsular malaysia. | slipper oyster crassostrea iredalei is a species of good demand for its sweet flavor and white coloured flesh. the filter feeding nature predisposes oysters to accumulation of pathogenic and heavy metals in waters impacted by sewage pollutions and may thus render the oysters unfit for human consumption. a study was undertaken to investigate the presence of bacteria flora and heavy metal concentrations in cultivated oysters crassostrea iredalei at setiu wetland, terengganu, the only source of cul ... | 2008 | 18369732 |
| isolation and characterization of two groups of novel marine bacteria producing violacein. | thirteen strains of novel marine bacteria producing a purple pigment were isolated from the pacific coast of japan. they were divided into two groups based on their 16s ribosomal rna gene sequences, and both groups of bacteria belonged to the genus pseudoalteromonas. the uv-visible spectrum of the pigment was identical to those of violacein, a pigment produced by several species of bacteria including chromobacterium violaceum, an opportunistic pathogen. further analysis of the chemical structure ... | 2008 | 17968625 |
| a study of natural attenuation processes involved in a microcosm model of a crude oil-impacted wetland sediment in the niger delta. | sediment sample from a previously impacted ochani stream was recreated in four glass chambers (a-d) as microcosms. the aim was to model and compare natural attenuation processes to forced aeration for remediation of a crude oil-impacted ecosystem. the initial hydrocarbon concentration was 90,212 mg/kg of sediment. after 60 days, the natural attenuation processes of photooxidation, evaporation, volatilization and biodegradation accounted for 31.9% of the total hydrocarbon removed while 13% was at ... | 2008 | 17988860 |
| the violacein biosynthetic enzyme vioe shares a fold with lipoprotein transporter proteins. | vioe, an unusual enzyme with no characterized homologues, plays a key role in the biosynthesis of violacein, a purple pigment with antibacterial and cytotoxic properties. without bound cofactors or metals, vioe, from the bacterium chromobacterium violaceum, mediates a 1,2 shift of an indole ring and oxidative chemistry to generate prodeoxyviolacein, a precursor to violacein. our 1.21 a resolution structure of vioe shows that the enzyme shares a core fold previously described for lipoprotein tran ... | 2008 | 18171675 |
| crystal structure of vioe, a key player in the construction of the molecular skeleton of violacein. | violacein and the indolocarbazoles are naturally occurring bisindole products with various biological activities, including antitumor activity. although these compounds have markedly different molecular skeletons, their biosynthetic pathways share the same intermediate "compound x," which is produced from l-tryptophan via indole-3-pyruvic acid imine. compound x is a short-lived intermediate that is spontaneously converted to chromopyrrolic acid for indolocarbazole biosynthesis, whereas vioe tran ... | 2008 | 18171677 |
| human chromobacterium violaceum infection in southeast asia: case reports and literature review. | chromobacterium violaceum infection in humans is a rare tropical and subtropical disease. the awareness of this organism is limited in spite its ubiquitous distribution. several cases have been reported from southeast asia. a localized infection followed by an overwhelming septicemia and metastatic lesions is the usual pattern of this illness. optimal antimicrobial treatment and duration are unknown. consequently, the outcome is usually fatal. the study reported two patients who suffered from fu ... | 2008 | 18564684 |
| paludibacterium yongneupense gen. nov., sp. nov., isolated from a wetland, yongneup, in korea. | a cream-coloured bacterial strain, 5yn8-15(t), was isolated from a wetland, yongneup, in the inje region of the republic of korea. the bacterium was facultatively anaerobic, gram-negative, motile with a single polar flagellum and curved-rod-shaped. based on 16s rrna gene sequence analysis, strain 5yn8-15(t) is a member of the betaproteobacteria. closely related taxa were gulbenkiania mobilis e4fc31(t) (94.9% sequence similarity), chromobacterium species (94.1-94.4%), aquitalea magnusonii tro-001 ... | 2008 | 18175708 |
| n-acylhomoserine lactone regulates violacein production in chromobacterium violaceum type strain atcc 12472. | in tests, chromobacterium violaceum atcc 12472 produced several n-acyl-l-homoserine lactones (ahls). of these, n-(3-hydroxydecanoyl)-l-homoserine lactone was dominant, and controlled violacein production by quorum sensing. strain vir07, an ahl-deficient mutant, did not produce violacein. violacein production in vir07 was induced by adding long-chain ahls (c10-c16), but was inhibited by adding short-chain ahls (c4-c8). strain vir07 showed the response of violacein production when ahls diffused fr ... | 2008 | 18177311 |
| chromobacterium violaceum cellulitis and sepsis following cutaneous marine trauma. | chromobacterium violaceum is a gram-negative bacillary organism that characteristically produces the purple pigment violacein. documented as the cause of clinically relevant human infections in only 35 cases in the united states, c violaceum is particularly seen in patients with a history of cutaneous injury or trauma. we report the case of an 18-year-old woman who was struck by a propeller in a boating accident and sustained multiple deep lacerations of her right lower extremity. shortly after ... | 2008 | 18441852 |
| hydrogen peroxide linked to lysine oxidase activity facilitates biofilm differentiation and dispersal in several gram-negative bacteria. | the marine bacterium pseudoalteromonas tunicata produces an antibacterial and autolytic protein, alpp, which causes death of a subpopulation of cells during biofilm formation and mediates differentiation, dispersal, and phenotypic variation among dispersal cells. the alpp homologue (loda) in the marine bacterium marinomonas mediterranea was recently identified as a lysine oxidase which mediates cell death through the production of hydrogen peroxide. here we show that alpp in p. tunicata also act ... | 2008 | 18502869 |
| diversity and quorum-sensing signal production of proteobacteria associated with marine sponges. | marine sponges are hosts to diverse and dense bacterial communities and thus provide a potential environment for quorum sensing. quorum sensing, a key factor in cell-cell communication and bacterial colonization of higher animals, might be involved in the symbiotic interactions between bacteria and their sponge hosts. given that marine proteobacteria are known to produce n-acyl homoserine lactone (ahl) signal molecules, we tested the production of ahls by alpha- and gammaproteobacteria isolated ... | 2008 | 18211268 |
| purification and characterization of chromobacterium sp. ds-1 cholesterol oxidase with thermal, organic solvent, and detergent tolerance. | a new screening method for 6beta-hydroperoxycholest-4-en-3-one (hceo)-forming cholesterol oxidase was devised in this study. as the result of the screening, a novel cholesterol oxidase producer (strain ds-1) was isolated and identified as chromobacterium sp. extracellular cholesterol oxidase of strain ds-1 was purified from the culture supernatant. the molecular mass of the purified enzyme was 58 kda. this enzyme showed a visible adsorption spectrum having peaks at 355 and 450 nm, like a typical ... | 2008 | 18512056 |
| lipases at interfaces: unique interfacial properties as globular proteins. | the adsorption behavior of two globular proteins, lipase from rhizomucor miehei and beta-lactoglobulin, at inert oil/water and air/water interfaces was studied by the pendant drop technique. the kinetics and adsorption isotherms were interpreted for both proteins in different environments. it was found that the adopted mathematical models well describe the adsorption behavior of the proteins at the studied interfaces. one of the main findings is that unique interfacial properties were observed f ... | 2008 | 18512870 |
| antibacterial activity of halogenated sesquiterpenes from malaysian laurencia spp. | during our studies on malaysian laurencia species, brominated metabolites, tiomanene, acetylmajapolene b, and acetylmajapolene a were isolated from an unrecorded species collected at pulau tioman, pahang along with known majapolene b and majapolene a. acetylmajapolene a was a mixture of diastereomers as in the case of majapolene a. tiomanene may be a plausible precursor for acetylmajapolenes b and a. in addition, three known halogenated sesquiterpenes and two known halogenated c(15) acetogenins ... | 2008 | 18718619 |
| the 1.25 a resolution structure of phosphoribosyl-atp pyrophosphohydrolase from mycobacterium tuberculosis. | phosphoribosyl-atp pyrophosphohydrolase is the second enzyme in the histidine-biosynthetic pathway, irreversibly hydrolyzing phosphoribosyl-atp to phosphoribosyl-amp and pyrophosphate. it is encoded by the hise gene, which is present as a separate gene in many bacteria and archaea but is fused to hisi in other bacteria, fungi and plants. because of its essentiality for growth in vitro, hise is a potential drug target for tuberculosis. the crystal structures of two native (uncomplexed) forms of h ... | 2008 | 18560150 |
| anthranilate synthase subunit organization in chromobacterium violaceum. | tryptophan is an aromatic amino acid used for protein synthesis and cellular growth. chromobacterium violaceum atcc 12472 uses two tryptophan molecules to synthesize violacein, a secondary metabolite of pharmacological interest. the genome analysis of this bacterium revealed that the genes trpa-f and paba-b encode the enzymes of the tryptophan pathway in which the first reaction is the conversion of chorismate to anthranilate by anthranilate synthase (as), an enzyme complex. in the present study ... | 2008 | 18949702 |
| ppsy: a vector for the stable cloning and expression of streptomycete single gene phenotypes in escherichia coli. | ppsy is a 12kb cloning vector derived from the incw plasmid r388, which provides a rapid and easy way to stably clone phenotypes encoded in dna segments <10kb. in the present study three different genes were amplified by pcr, cloned into pgem-t easy and sub-cloned into the ecori site of ppsy. the first gene, vioa, is a fad-dependent l-tryptophan amino acid oxygenase from the high g+c gram-negative bacterium chromobacterium violaceum. vioa is involved in the synthesis of the indolocarbazole antit ... | 2008 | 18406459 |
| kinetics of thermal unfolding of phenylalanine hydroxylase variants containing different metal cofactors (feii, coii, and znii) and their isokinetic relationship. | the kinetics of thermal unfolding of apo- and holo-chromobacterium violaceum phenylalanine hydroxylase (cpah) was investigated using circular dichroism (cd) over the temperature range 44-76 degrees c. in addition to the native cofactor (feii), the unfolding kinetics of holo-cpah was characterized using znii and coii as cofactors. kinetic profiles for apo- and holo-cpah showed a single-phase exponential rise in the cd signal at lambda=222 nm and a first-order dependence on protein concentration. ... | 2008 | 18433092 |
| neonatal septicaemia in calabar, nigeria. | a three-year survey of neonatal septicaemia (363 bacteriologically proven cases) in the university of calabar teaching hospital, calabar, has demonstrated that the dominant blood isolate was staphylococcus aureus (53%) followed by unclassified coliforms (20%), an unexpected chromobacterium violaceum (5%). the incidence of neonatal septicaemia was 54.9 per 1000 live births for inborn infants. the predominant organisms were largely susceptible to gentamicin, ceftriazone and cefuroxime with a morta ... | 2008 | 18453516 |
| structural basis for mannose recognition by a lectin from opportunistic bacteria burkholderia cenocepacia. | chronic colonization of the lungs by opportunist bacteria such as pseudomonas aeruginosa and members of the bcc (burkholderia cepacia complex) is the major cause of morbidity and mortality among cf (cystic fibrosis) patients. pa-iil (lecb gene), a soluble lectin from ps. aeruginosa, has been the subject of much interest because of its very strong affinity for fucose. orthologues have been identified in the opportunist bacteria ralstonia solanacearum, chromobacterium violaceum and burkholderia of ... | 2008 | 18215132 |
| diversity in antifungal activity of strains of chromobacterium violaceum from the brazilian amazon. | chromobacterium violaceum is a free-living gram-negative bacterium found in soil and aquatic habitats; abundantly present in the brazilian amazon, it is an important example of exploitable microbial diversity of the tropics. in this study, 24 strains from the brazilian amazon and atcc 12472(t) were investigated for biocontrol potential of seven fungi pathogenic to soybean [glycine max (l.) merril] seed. both cells and the supernatants of two brazilian strains, 07-1 and 27-1, together with atcc 1 ... | 2008 | 18347828 |
| degradation of n-acyl homoserine lactone quorum sensing signal molecules by forest root-associated fungi. | a collection of mycorrhizal and nonmycorrhizal root-associated fungi coming from forest environments was screened for their ability to degrade n-acyl homoserine lactones (ahl) or to prevent ahl recognition by producing quorum sensing inhibitors (qsi). no production of qs-inhibitors or -activators was detected using the two biosensors chromobacterium violaceum cv026 and agrobacterium tumefaciens in the culture supernatant of these fungi. however, the ability to degrade c6- and 3o,c6-hsl was detec ... | 2008 | 18400006 |
| [successful treatment of a case with fatal sepsis caused by chromobacterium violaceum]. | 2007 | 18282432 | |
| stereochemical course of tryptophan dehydrogenation during biosynthesis of the calcium-dependent lipopeptide antibiotics. | [reaction: see text] hydrogen atoms are abstracted from the c2' and c3'-pro-s positions of an (s)-tryptophanyl precursor, with overall syn stereochemistry, during the biosynthesis of the c-terminal z-2',3'-dehydrotryptophan residue of the calcium-dependent lipopeptide antibiotics (cdas) in streptomyces coelicolor. the absence of beta-hydroxytryptophanyl, or other possible intermediates, further suggests a direct dehydrogenation mechanism similar to that proposed for the l-tryptophan 2',3'-oxidas ... | 2007 | 17355143 |
| fatal septicaemia due to chromobacterium violaceum. | human infection caused by chromobacterium violaceum is rare but when it occurs, it is associated with a high mortality rate. this is a report of a young adult male who presented as a surgical emergency and succumbed soon after. the most common feature of this infection is sepsis, followed by cutaneous involvement and liver abscesses. chromobacterium infection as a differential in a case of sepsis is important for clinicians to suspect, especially in tropical countries. | 2007 | 18198747 |
| dietary phytochemicals as quorum sensing inhibitors. | quorum sensing (qs) is a cell density dependent expression of species in bacteria mediated by hormone like compounds called autoinducers (ai). several processes responsible for successful establishment of bacterial infection are mediated by qs. inhibition of qs is therefore being considered as a new target for antimicrobial chemotherapy. dietary phytochemicals are secondary metabolites in plants known to have several health benefits including antimicrobial activity. however, their ability to inh ... | 2007 | 17499938 |
| evaluation of different compounds as quorum sensing inhibitors in pseudomonas aeruginosa. | quorum sensing (qs) controls systems affecting the pathogenicity of many microorganisms; its interruption has an anti-pathogenic effect and can be used in the treatment of bacterial infections. in this study we evaluated qs regulation by pseudomonas aeruginosa strains and qs inhibition (qsi) by different compounds. the inhibitory activity of 3 macrolide and 3 lincosamide drugs, resveratrol, garlic extract and n-acetylcysteine was tested on 4 p. aeruginosa strains isolated from cystic fibrosis (c ... | 2007 | 17855182 |
| biosynthesis of violacein: a genuine intermediate, protoviolaceinic acid, produced by vioabde, and insight into vioc function. | a biosynthetic intermediate of violacein produced by the mixed enzymes of vioabde was elucidated to be 5-(5-hydroxy-1h-indol-3-yl)-3-(1h-indol-3-yl)-1h-pyrrole-2-carboxylic acid, named protoviolaceinic acid, indicating that vioc, responsible for the final biosynthetic step, works to oxygenate at the 2-position of the right side indole ring, and that the oxygenation reaction to form the central pyrrolidone core proceeds in a non-enzymatic fashion. | 2007 | 17925955 |
| violacein: properties and biological activities. | the violet pigment violacein is an indole derivative, isolated mainly from bacteria of the genus chromobacterium, which exhibits important antitumoral, antimicrobial and antiparasitary properties. furthermore, the formulation of violacein in different polymeric carriers developed so far offers alternative approaches to overcoming physiological barriers and undesirable physicochemical properties in vivo, thus improving its efficacy. | 2007 | 17927569 |
| nonionic surfactants: a key to enhance the enzyme activity at cationic reverse micellar interface. | the primary objective of the present study is to understand how the different nonionic surfactants modify the anisotropic interface of cationic water-in-oil (w/o) microemulsions and thus influences the catalytic efficiency of surface-active enzymes. activity of chromobacterium viscosum lipase (cv-lipase) was estimated in several mixed reverse micelles prepared from ctab and four different nonionic surfactants, brij-30, brij-92, tween-20, and tween-80/water/isooctane/n-hexanol at different z ([co ... | 2007 | 17348695 |
| effect of the pretreatment of lipase with organic solvents on its conformation and activity in reverse micelles. | the activity and conformation of chromobacterium viscosum lipase-pretreated with various organic solvents were investigated. the pretreatment of lipase led to a substantial increase of enzyme activity in aot (sodium bis [2-ethyl -1-hexyl] sulfosuccinate)/isooctane/water reverse micelles. among the organic solvents used, n-hexane was found to be most effective. it was observed that higher hexane content with shorter agitation time and vice versa had almost the same effect on the initial activity ... | 2007 | 18025586 |
| fatal septicemia caused by chromobacterium violaceum in a child from colombia. | a 4-year old child living in colombia presented with a history of fever and severe abdominal pain for four days. the patient developed pneumonia, septic shock, multiple organ failure and died on the fifth day of hospitalization. chromobacterium violaceum was isolated from admission blood cultures and was resistant to ampicillin, cephalosporins, carbapenems and aminoglycosides. | 2007 | 18157408 |
| crystallization and preliminary x-ray diffraction analysis of omega-amino acid:pyruvate transaminase from chromobacterium violaceum. | the enzyme omega-transaminase catalyses the conversion of chiral omega-amines to ketones. the recombinant enzyme from chromobacterium violaceum has been purified to homogeneity. the enzyme was crystallized from peg 4000 using the microbatch method. data were collected to 1.7 a resolution from a crystal belonging to the triclinic space group p1, with unit-cell parameters a = 58.9, b = 61.9, c = 63.9 a, alpha = 71.9, beta = 87.0, gamma = 74.6 degrees . data were also collected to 1.95 a from a sec ... | 2007 | 17277454 |
| analysis of chromobacterium sp. natural isolates from different brazilian ecosystems. | chromobacterium violaceum is a free-living bacterium able to survive under diverse environmental conditions. in this study we evaluate the genetic and physiological diversity of chromobacterium sp. isolates from three brazilian ecosystems: brazilian savannah (cerrado), atlantic rain forest and amazon rain forest. we have analyzed the diversity with molecular approaches (16s rrna gene sequences and amplified ribosomal dna restriction analysis) and phenotypic surveys of antibiotic resistance and b ... | 2007 | 17584942 |
| inhibition of quorum sensing-regulated behaviors by scorzonera sandrasica. | many gram-negative bacteria use n-acyl homoserine lactone signal molecules to monitor their own population density and coordinate gene regulation in a process called quorum sensing (qs). increasing evidence implies that certain eukaryotes produce qs-inhibitory compounds. in this work, we tested 46 terrestrial plants materials for their ability to inhibit qs-regulated behaviors in different bacterial species. plant materials were dried and extracted using different solvents. the chloroform-solubl ... | 2007 | 17597339 |
| cloning and high-level production of a chitinase from chromobacterium sp. and the role of conserved or nonconserved residues on its catalytic activity. | a gene encoding an alkaline (pi of 8.67) chitinase was cloned and sequenced from chromobacterium sp. strain c-61. the gene was composed of 1,611 nucleotides and encoded a signal sequence of 26 n-terminal amino acids and a mature protein of 510 amino acids. two chitinases of 54 and 52 kda from both recombinant escherichia coli and c-61 were detected on sds-page. maximum chitinase activity was obtained in the culture supernatant of recombinant e. coli when cultivated in tb medium for 6 days at 37 ... | 2007 | 17294188 |
| [chromobacterium violaceum septicemia: first case report in the french west indies]. | we report a fatal case of chromobacterium violaceum septicemia in a 42-year-old farm worker living in the french west indies. the bacteria found in the muddy soil and the stagnant water of tropical and subtropical regions is rarely a source of human infection. | 2007 | 17905550 |
| inhibitory effects of histone deacetylase inhibitor depsipeptide on benzo(a)pyrene- and cyclophosphamide-induced genotoxicity in swiss albino mice. | depsipeptide (fk228 or fr901228) was evaluated in the mouse bone marrow micronucleus test for its possible protective effect against chromosomal damage induced by benzo(a)pyrene and cyclophosphamide. three doses of depsipeptide (0.5, 1, and 1.5 mg/kg body weight) were given intravenously to mice for 7 consecutive days prior to administration of genotoxins under investigation. all the three doses of depsipeptide were effective in exerting a protective effect against both benzo(a)pyrene and cyclop ... | 2007 | 17365146 |
| the effect of quorum-sensing blockers on the formation of marine microbial communities and larval attachment. | we studied the effect of the quorum-sensing (qs) blockers 5-hydroxy-3[(1r)-1-hydroxypropyl]-4-methylfuran-2(5h)-one (fur1), (5r)-3,4-dihydroxy-5-[(1s)-1,2-dihydroxyethyl]furan-2(5h)-one (fur2) and triclosan (tri) on the formation of bacterial biofilms, and the effect of these biofilms on the larval attachment of the polychaete hydroides elegans and the bryozoan bugula neritina. 14-day-old subtidal biofilms were harvested from artificial substrata and were allowed to develop in the laboratory wit ... | 2007 | 17371321 |
| genetic organization of the biosynthetic gene cluster for the indolocarbazole k-252a in nonomuraea longicatena jcm 11136. | indolocarbazole metabolite k-252a is a natural product that was previously reported as a potent protein kinase c inhibitor with in vitro and in vivo potency. from a biosynthetic viewpoint, this compound possesses structurally interesting features such as an unusual furanosyl sugar moiety, which are absent in the well-studied staurosporine and rebeccamycin. a cosmid library from genomic dna of nonomuraea longicatena jcm 11136 was constructed and screened for the presence of genes to be involved i ... | 2007 | 17396254 |
| characterization of a gene cluster responsible for the biosynthesis of anticancer agent fk228 in chromobacterium violaceum no. 968. | a gene cluster responsible for the biosynthesis of anticancer agent fk228 has been identified, cloned, and partially characterized in chromobacterium violaceum no. 968. first, a genome-scanning approach was applied to identify three distinctive c. violaceum no. 968 genomic dna clones that code for portions of nonribosomal peptide synthetase and polyketide synthase. next, a gene replacement system developed originally for pseudomonas aeruginosa was adapted to inactivate the genomic dna-associated ... | 2007 | 17400765 |
| chromobacterium subtsugae sp. nov., a betaproteobacterium toxic to colorado potato beetle and other insect pests. | strain praa4-1(t), a motile, gram-negative, violet-pigmented bacterium, was isolated from maryland forest soil and found to be orally toxic to colorado potato beetle larvae and other insects. morphological, biological, biochemical and molecular characterization revealed that this strain was most similar to chromobacterium violaceum, the type species and only currently recognized member of the genus chromobacterium. dna-dna hybridization with c. violaceum atcc 12472(t) was 27 %. phylogenetic anal ... | 2007 | 17473247 |
| gulbenkiania mobilis gen. nov., sp. nov., isolated from treated municipal wastewater. | a bacterial strain (e4fc31(t)) isolated from treated municipal wastewater was characterized phenotypically and phylogenetically. cells were gram-negative, curved rods with a polar flagellum. the isolate was catalase-, oxidase- and arginine dihydrolase-positive, and able to grow between 15 and 45 degrees c and between ph 5.5 and 9.0. the predominant fatty acids were c(16 : 1)/iso-c(15 : 0) 2-oh and c(16 : 0), the major respiratory quinone was ubiquinone 8 and the g+c content of the genomic dna wa ... | 2007 | 17473267 |
| n-acyl homoserine lactones are degraded via an amidolytic activity in comamonas sp. strain d1. | comamonas strain d1 enzymatically inactivates quorum-sensing (qs) signal molecules of the n-acyl homoserine lactone (n-ahsl) family, and exhibits the broadest inactivation range of known bacteria. it degrades n-ahsl with acyl-side chains ranging from 4 to 16 carbons, with or without 3-oxo or 3-hydroxy substitutions. n-ahsl degradation yields hsl but not n-acyl homoserine: strain d1 therefore harbors an amidohydrolase activity. strain d1 is the fifth bacterium species in which an n-ahsl amidohydr ... | 2007 | 17136382 |
| the serratia-type hemolysin of chromobacterium violaceum. | chromobacterium violaceum is a gram-negative opportunistic human pathogen and an inhabitant of tropical soils and waterways. although known primarily for the synthesis of the pigment violacein, and more recently as a reporter strain for quorum sensing, clinical reports of chromobacteriosis comprise the largest block of published literature on this organism. genome sequencing has revealed many potential virulence factors in this microorganism, and this paper establishes the presence in c. violace ... | 2007 | 17169000 |
| sepsis by chromobacterium violaceum: first case report from colombia. | chromobacterium violaceum is found in tropical and subtropical regions; it is the only chromobacterium species pathogenic for humans. due to its rare presentation, physicians often ignore the importance of this pathogen. we report a fulminant fatal case of bacteremia in a 38-year-old colombian man. the clinical manifestations were fever, thoracic pain, respiratory failure and death. his condition, from the beginning of clinical diagnosis, went into continuous deterioration, till his death, withi ... | 2007 | 17874003 |
| one step engineering of t7-expression strains for protein production: increasing the host-range of the t7-expression system. | the t7-expression system has been very useful for protein expression in escherichia coli. however, it is often desirable to over-express proteins in species other than e. coli. here, we constructed an inducible broad-host-range t7-expression transposon, which allows simple one-step construction of t7-expression strains in various species, providing the option to over-express proteins of interest in a broader host-range. this transposon contains the t7 rna polymerase driven by the lacuv5 promoter ... | 2007 | 17716915 |
| [sepsis caused by pigmented and no pigmented chromobacterium violaceum]. | chromobacterium violaceum sepsis is rare but associated with a high mortality rate. we report a fatal case of c. violaceum sepsis in a 6 years old venezuelan indian boy. clinical manifestations were fever and swelling in the right inguinal region. the initial diagnosis was an appendicular plastron. appendicectomy was performed and during surgery a right psoas abscess was identified that resulted culture positive for pigmented c. violaceum. blood cultures were positive for a pigmented and non pig ... | 2007 | 17989847 |
| signal mimics derived from a metagenomic analysis of the gypsy moth gut microbiota. | bacterial signaling is an important part of community life, but little is known about the signal transduction pathways of the as-yet-uncultured members of microbial communities. to address this gap, we aimed to identify genes directing the synthesis of signals in uncultured bacteria associated with the midguts of gypsy moth larvae. we constructed a metagenomic library consisting of dna extracted directly from the midgut microbiota and analyzed it using an intracellular screen designated metrex, ... | 2007 | 17435000 |
| toxicity of chromobacterium subtsugae to southern green stink bug (heteroptera: pentatomidae) and corn rootworm (coleoptera: chrysomelidae). | diabrotica spp. (coleoptera: chrysomelidae) beetles and southern green stink bugs, nezara viridula (l.) (heteroptera: pentatomidae), are pests on corn, zea mays l., and soybean, glycine max (l.) merr., as well as on cucurbits. control of these insects has depended on chemicals. an alternative to chemical control is the use of biologicals. use of bacteria, fungi, viruses, pheromones, and metabolites to control these insects can potentially improve resistance management and reduce pesticide use. o ... | 2007 | 17598525 |
| chromobacterium violaceum infection in taiwan: a case report and literature review. | chromobacterium violaceum is a facultative anaerobic, gram-negative bacillus which inhabits stagnant water in tropical and subtropical regions. we describe the case of an 80-year-old female patient with c. violaceum bacteremia due to traumatic wound infected by contaminated water and soil. she had persistent fever, hypotension and neutrophilic leukocytosis on admission. two sets of blood cultures yielded c. violaceum. the patient was successfully treated with levofloxacin. since the first case f ... | 2007 | 17639170 |
| cytotoxic activity of violacein in human colon cancer cells. | several studies have shown that violacein, a purple pigment extracted from chromobacterium violaceum, is capable to induce apoptosis in a variety of cancer cells, including those leukemia cell lines. herein, we examined the effects of violacein on reactive oxygen species (ros) production during the apoptotic colon cancer cell death. we demonstrate that violacein mediates ros production followed by activation of caspase-3, release of cytochrome c, and calcium release to citosol in caco-2 cells. m ... | 2006 | 16889929 |
| fatal septicaemia from chromobacterium violaceum: case reports and review of the literature. | chromobacterium violaceum rarely causes infection in humans and its mechanism of pathogenicity is not well understood. human infection carries a high mortality rate with a fulminating clinical progression. a high index of suspicion is required for diagnosis, and is based on recovering the organisms from blood cultures or other appropriate specimens. we present three cases of human infection managed in a tertiary referral hospital in hong kong with a review of the literature. | 2006 | 16760554 |
| unusual entropy-driven affinity of chromobacterium violaceum lectin cv-iil toward fucose and mannose. | the purple pigmented bacterium chromobacterium violaceum is a dominant component of tropical soil microbiota that can cause rare but fatal septicaemia in humans. its sequenced genome provides insight into the abundant potential of this organism for biotechnological and pharmaceutical applications and allowed an orf encoding a protein that is 60% identical to the fucose binding lectin (pa-iil) from pseudomonas aeruginosa and the mannose binding lectin (rs-iil) from ralstonia solanacearum to be id ... | 2006 | 16768446 |
| epr and uv-vis studies of the nitric oxide adducts of bacterial phenylalanine hydroxylase: effects of cofactor and substrate on the iron environment. | phenylalanine hydroxylase from chromobacterium violaceum (cpah), which catalyzes phenylalanine oxidation to tyrosine, is homologous to the catalytic domain of eukaryotic pahs. previous crystallographic and spectroscopic studies on mammalian pah conflict on whether o2 binds to the open-coordination site or displaces the remaining water ligand to yield either a six- or a five-coordinate iron, respectively. the abilities of nitric oxide to behave as an oxygen mimic and a spectroscopic probe of ferr ... | 2006 | 16676991 |
| production and properties of the native chromobacterium violaceum fucose-binding lectin (cv-iil) compared to homologous lectins of pseudomonas aeruginosa (pa-iil) and ralstonia solanacearum (rs-iil). | chromobacterium violaceum is a versatile, violet pigment (violacein)-producing beta-proteobacterium, confined to tropical and subtropical regions, dwelling in soil and water, like pseudomonas aeruginosa and ralstonia solanacearum. these three bacteria are saprophytes that occasionally become aggressive opportunistic pathogens virulently attacking animals (the first two) and plants (the third). the recent availability of their genome sequences enabled identification in the c. violaceum genome of ... | 2006 | 16436433 |
| aquitalea magnusonii gen. nov., sp. nov., a novel gram-negative bacterium isolated from a humic lake. | a gram-negative, rod-shaped, non-spore-forming betaproteobacterium (tro-001dr8t) was isolated from humic-lake samples collected from northern wisconsin, usa. on the basis of 16s rrna gene sequence analysis, strain tro-001dr8t belonged to the family neisseriaceae, and the phylogenetic distance from its closest relative, chromobacterium violaceum, was 95 %. strain tro-001dr8t lacked the violet pigmentation of c. violaceum and shared only 26 % dna-dna relatedness with c. violaceum. the dna g+c cont ... | 2006 | 16585708 |
| chromobacterium violaceum infection. | 2006 | 16681318 | |
| [chromobacterium violaceum peritonitis: case report and literature review]. | we report a case of chromobacterium violaceum infection and we review the literature for all published cases. c. violaceum grew from a peritoneal fluid of a 47-year-old woman operated on for peritonitis following perforative gastroduodenal ulcer. she was just coming back from a 1-month-holyday in french guyana, where she might have been in contact with this micro-organism. the patient fully recovered after surgical management associated with antibiotic therapy consisting of ofloxacin plus pipera ... | 2006 | 16829475 |
| a fatal case of chromobacterium violaceum septicemia in hong kong. | chromobacterium violaceum causes a rare infection in human, usually in tropical or subtropical areas. we report a fatal case of c. violaceum infection affecting a 40-year-old previously healthy man in hong kong. he presented with a wound infection and lymphadenitis. despite multiple antibiotic treatment, including ciprofloxacin, he succumbed shortly after admission to the hospital. we report the epidemiological investigation findings and discuss the possible sources of infection. physicians shou ... | 2006 | 17333774 |
| [chromobacteriosis in ilhéus, bahia: epidemiologic, clinical and laboratorial investigation]. | in april/2004, a group of people traveled to a farm in a town in the south of bahia and afterwards, three teenagers from the same family developed symptoms of severe septicemia and two died. the health department carried out an epidemiologic, clinical, laboratory and environmental investigation that resulted in the identification of chromobacterium violaceum, in biological material from one of them, water and soil. this is the first report of the disease in bahia state. | 2006 | 16410927 |
| chromobacterium violaceum infection in two dogs. | chromobacterium violaceum is a saprophyte of soil and water in tropical and subtropical environments that is associated with rare but highly fatal infections in animals and humans. systemic infection was diagnosed in two critically ill dogs from florida. fever was absent in both dogs. both dogs were treated surgically and provided with intensive care, but only one survived. the identification of characteristic, violet-pigmented bacterial colonies on routine microbial cultures should alert microb ... | 2006 | 16527917 |
| effects of cyanide and dissolved oxygen concentration on biological au recovery. | the number of discarded electric devices containing traces of au is currently increasing. it is desirable to recover this au because of its valuable physicochemical properties. au is usually dissolved with relatively high concentrations of cyanide, which is associated with environmental risk. chromobacterium violaceum is able to produce and detoxify small amounts of cyanide, and may thus be able to recover au from discarded electric devices. this study investigated the effects of cyanide and dis ... | 2006 | 16567012 |
| alginate-chaperoned facile refolding of chromobacterium viscosum lipase. | urea denatured lipase from chromobacterium viscosum lipase could be refolded by addition of alginate with high guluronic acid content. the refolded molecule could be recovered by affinity precipitation. this approach resulted in recovery of 80% (of original activity) as compared to classical dilution method which gave only 21% activity recovery. dynamic light scattering showed that binding required about 45 min and activity data obtained from affinity precipitation experiments indicated that ref ... | 2006 | 16624637 |
| ecthyma gangrenosum and septic shock syndrome secondary to chromobacterium violaceum. | chromobacterium violaceum is a gram-negative bacterium of soil and water in tropical and subtropical environments. typically, it is considered a bacterium of low virulence although, uncommonly, it causes human infection, particularly in persons with defects in host defenses. infection generally follows exposure of broken skin to contaminated water and soil, and is often characterized by pustules, lymphadenitis, fever, and vomiting, as well as rapid dissemination and a high mortality rate. unfort ... | 2006 | 16631946 |
| effect of counterions on the activity of lipase in cationic water-in-oil microemulsions. | this paper delineates how the different counterions affect the physicochemical properties of the aqueous aggregates and thereby the lipase activities at the interface of cationic water-in-oil microemulsions. to this end, we have synthesized a series of cetyltrimethylammonium-based surfactants, 1-14, having aliphatic, aliphatic with aromatic substitution at the alpha position, and aromatic carboxylate anion as the counterion. the physicochemical characterizations of these aqueous aggregates were ... | 2006 | 17014111 |
| physicochemical studies on cetylammonium bromide and its modified (mono-, di-, and trihydroxyethylated) head group analogues. their micellization characteristics in water and thermodynamic and structural aspects of water-in-oil microemulsions formed with them along with n-hexanol and isooctane. | the micellization behavior of cetylammonium bromide and its mono-, di-, and trihydroxyethylated head group analogues and water/oil (w/o) microemulsion formation with them have been studied with detailed thermodynamic and structural considerations. the critical micellar concentration, micellar aggregation number, and behavior of the surfactants at the air/solution interface have been studied in detail. the results have been analyzed and discussed. the formation of the w/o microemulsion stabilized ... | 2006 | 16771402 |
| reevaluation of the violacein biosynthetic pathway and its relationship to indolocarbazole biosynthesis. | the biosynthetic pathways for violacein and for indolocarbazoles (rebeccamycin, staurosporine) include a decarboxylative fusion of two tryptophan units. however, in the case of violacein, one of the tryptophans experiences an unusual 1-->2 shift of the indole ring. the violacein biosynthetic gene cluster was previously reported to consist of four genes, vioabcd. here we studied the violacein pathway through expression of vio genes in escherichia coli and streptomyces albus. a pair of genes (vioa ... | 2006 | 16874749 |