TitleAbstractYear(sorted ascending)
chitinolytic activity in chromobacterium violaceum: substrate analysis and regulation by quorum sensing.quorum sensing control mediated by n-acyl homoserine lactone (ahl) signaling molecules has been established as a key feature of the regulation of exoenzyme production in many gram-negative bacteria. in chromobacterium violaceum atcc 31532 a number of phenotypic characteristics, including production of the purple pigment violacein, hydrogen cyanide, antibiotics, and exoproteases are known to be regulated by the endogenous ahl n-hexanoyl-l-homoserine lactone (hhl). in this study we show that c. vi ...19989721280
proposal of six new species in the genus microbacterium and transfer of flavobacterium marinotypicum zobell and upham to the genus microbacterium as microbacterium maritypicum comb. nov.reference strains, including two mis-named organisms, 'chromobacterium chocolatum' and flavobacterium marinotypicum, isolates from soil and clinical specimens, all previously recognized as aureobacterium or microbacterium, were characterized taxonomically. on the basis of morphological, physiological and chemotaxonomic characteristics, as well as dna-dna hybridization data, six new species and one new combination are proposed in the genus microbacterium: microbacterium ketosireducens sp. nov. (t ...19989734054
phenylalanine hydroxylase from chromobacterium violaceum. uncoupled oxidation of tetrahydropterin and the role of iron in hyroxylation.a gene encoding phenylalanine hydroxylase has been cloned from chromobacterium violaceum and expressed in escherichia coli. the purified phenylalanine hydroxylase contains copper, which does not support enzymatic activity. upon removal of copper by dithiothreitol (dtt), the enzyme contains substoichiometric amounts of calcium and zinc but little or no redox-active metal ions. the copper-depleted hydroxylase catalyzes the phenylalanine-dependent oxidation of 6, 7-dimethyltetrahydropterin (dmph4) ...19989748224
crystallization and preliminary x-ray analysis of ind, an enzyme with indole oxygenase activity from chromobacterium violaceum.ind, a redox flavoprotein from chromobacterium violaceum has been crystallized in the presence and absence of nadh. the crystals belong to the space group p41212 or its enantiomorph p43212 with a = 73.9 and c = 153.6 a. there is one molecule per asymmetric unit and the crystals diffract beyond 2.1 a resolution.19989761866
airways microbial flora in copd patients in stable clinical conditions and during exacerbations: a bronchoscopic investigation.patients affected with chronic obstructive pulmonary disease (copd) undergo frequent exacerbations of their illness characterized by increased cough and expectoration. the precise aetiology of these episodes often remains unknown. in the absence of clinical or radiographic signs of pneumonia, bacterial or viral cultures of sputum usually provide little useful information. thus, we performed fibreoptic bronchoscopy using a protected specimen brush (psb) to obtain uncontaminated secretions for cul ...19989785808
production of acyl-homoserine lactone quorum-sensing signals by gram-negative plant-associated bacteria.many gram-negative bacteria regulate expression of specialized gene sets in response to population density. this regulatory mechanism, called autoinduction or quorum-sensing, is based on the production by the bacteria of a small, diffusible signal molecule called the autoinducer. in the most well-studied systems the autoinducers are n-acylated derivatives of l-homoserine lactone (acyl-hsl). signal specificity is conferred by the length, and the nature of the substitution at c-3, of the acyl side ...19989805399
stability of porcine and microbial lipases to conditions that approximate the proventriculus of young vitro experiments were conducted to characterize the activity and the stability of lipase from animal (crude porcine, cpl; lyophilized porcine, lpl), fungal (rhizopus arrhizus, ral; aspergillus niger, anl), and bacterial (two pseudomonas spp., pl1, pl2; and chromobacterium viscosum, cvl) sources when exposed to conditions associated with the glandular stomach. activity was measured at ph 3 to 8, 40 c and then monitored in response to temperature (40 c), time of exposure (0 and 30 min), ph (3 ...19989835341
stability of porcine and microbial lipases to conditions that approximate the small intestine of young vitro experiments were conducted to study the stability of lipase activities from bacterial, fungal, and animal sources under conditions that approximate the small intestine. in the first experiment, the effects of preincubation with trypsin (500, 1,000, and 2,000 u/ml), chymotrypsin (200, 400, and 800 u/ml), and trypsin plus chymotrypsin (tc; 2,000 u/ml trypsin + 800 u/inl chymotrypsin) for 30 min at 40 c, on lipase activities from sources of pseudomonas spp. (pl1, pl2), chromobacterium visc ...19989835342
multiple intensified performance of an enzyme-catalyzed reaction in organic medium.a lipase-catalyzed glycerolysis reaction (a transesterification between polyunsaturated fatty acid ethyl ester [pufa] and glycerol) was investigated. its performance was multiply intensified by (1) using a lipase having high specific activity, high activity in organic solvent, and high tolerance in organic solvent; (2) immobilization on fine caco3 powder (cheap and safe material, easy physical adsorption method of immobilization, reusable); (3) reaction in vacuo resulting in 100% conversion and ...199810075632
two cases of chromobacterium violaceum infection after injury in a subtropical region.chromobacterium violaceum is a gram-negative rod and is isolated from soil and water in tropical and subtropical regions. the species have pigmented and nonpigmented colony types. infections caused by nonpigmented strains are rare. we report on two cases of infection caused by both pigmented and nonpigmented strains of c. violaceum. two 24-year-old korea airline stewardesses were admitted to inha university hospital, inchon, south korea, on 9 august 1997, 3 days after an airplane accident in gua ...199910325383
molecular dynamics of microbial lipases as determined from their intrinsic tryptophan fluorescence.we have studied the intrinsic tryptophan fluorescence of the lipases from chromobacterium viscosum (cvl), pseudomonas species (psl), and rhizopus oryzae (rol) in aqueous buffer, zwitterionic detergent micelles, and isopropanol-water mixtures. it was the purpose of this study to obtain information about biophysical properties of the respective enzymes under conditions that modulate enzyme activities and stereoselectivities to a significant extent. according to their decay-associated emission spec ...199910388774
chromobacterium violaceum sepsis accompanied by bacteria-associated hemophagocytic syndrome in a japanese man. 199910421288
cloning, molecular analysis, and expression of the polyhydroxyalkanoic acid synthase (phac) gene from chromobacterium violaceum.the polyhydroxyalkanoic acid synthase gene from chromobacterium violaceum (phac(cv)) was cloned and characterized. a 6.3-kb bamhi fragment was found to contain both phac(cv) and the polyhydroxyalkanoic acid (pha)-specific 3-ketothiolase (phaa(cv)). escherichia coli strains harboring this fragment produced significant levels of pha synthase and 3-ketothiolase, as judged by their activities. while c. violaceum accumulated poly(3-hydroxybutyrate) or poly(3-hydroxybutyrate-co-3-hydroxyvalerate) when ...199910427049
hydrophobic interaction chromatography of chromobacterium viscosum lipase on polypropylene glycol immobilised on sepharose.the fractionation of chromobacterium viscosum lipase was performed using a polypropylene glycol-sepharose gel. the influence of mobile phase composition on the adsorption of lipase on the gel was studied and it was found that the retention of lipase depends on the salt used and increased with increasing the ionic strength. the retention was not strongly affected by changing the ph value of the mobile phase. by using 20% (w/v) ammonium sulphate in phosphate buffer a total retention of lipase on t ...199910457439
regulation of expression of the nonhemolytic phospholipase c of burkholderia cepacia.burkholderia cepacia is an opportunistic pathogen that causes serious pulmonary infections in cystic fibrosis patients. we have purified and partially characterized one potential virulence factor for the organism-a nonhemolytic phospholipase c-and we studied the effect of iron restriction and choline and phosphate concentrations on the expression of phospholipase c. iron limitation did not affect expression, the effect of choline was variable, and high phosphate concentrations repressed expressi ...199910525838
diversity of culturable heterotrophic aerobic bacteria in pristine stream bed sediments.more than 900 culturable, heterotrophic aerobic isolates were obtained from the sediments of a forested, pristine stream and analyzed using three classical microbiological tests: api 20e, amplified ribosomal dna restriction analysis (ardra), and fatty acid analysis. gram-negative bacteria comprised most of the heterotrophic aerobic isolates (66.7%), similar to other oligotrophic environments. the isolates were assigned to the genus level as pseudomonas, flavobacterium, micrococcus, bacillus, chr ...199910907425
skin infections and infestations in aboriginal communities in northern australia.the most important skin infections in aboriginal communities in central and northern australia are scabies and streptococcal pyoderma. scabies is endemic in many remote aboriginal communities, with prevalences in children up to 50%. the cycles of scabies transmission underlie much of the pyoderma. up to 70% of children have skin sores, with group a streptococcus (gas) the major pathogen. group a streptococcus is responsible for the continuing outbreaks of post-streptococcal glomerulonephritis an ...200010954983
fatal and non-fatal chromobacterial septicemia: report of two cases.chromobacterium violaceum is frequently found in soil and water in tropical and subtropical regions. the organism rarely causes infection in humans, but is associated with a high mortality rate when it occurs. septicemia associated with abscess in multiple organs such as the liver, skin, lungs, spleen, lymph nodes, and brain has been reported. we report on 2 patients with systemic infections with chromobacterium violaceum. one presented with a fulminant course with multiple organ involvement and ...200011039252
sequence analysis and functional characterization of the violacein biosynthetic pathway from chromobacterium violaceum.violacein is a purple-colored, broad-spectrum antibacterial pigment that has a dimeric structure composed of 5-hydroxyindole, oxindole and 2-pyyrolidone subunits formed by the condensation of two modified tryptophan molecules. the violacein biosynthetic gene cluster from chromobacterium violaceum was characterized by dna sequencing, transposon mutagenesis, and chemical analysis of the pathway intermediates produced heterologously in escherichia. coli. the violacein biosynthetic gene cluster span ...200011075927
a spectroscopic analysis of thermal stability of the chromobacterium viscosum lipase.the thermal stability of the lipase from chromobacterium viscosum was assessed by deactivation (loss of activity), fluorescence, circular dichroism (cd) and static light scattering (sls) measurements. lipase fluorescence emission is dominated by the tryptophyl contribution. an increase in the tyrosyl contribution from 2 to 16% was only observed upon prolonged incubation at 60 degrees c. the effect of temperature on the tryptophyl quantum yield was studied and two activation energies were calcula ...200011099174
violacein cytotoxicity and induction of apoptosis in v79 cells.violacein, a pigment produced by chromobacterium violaceum, is reported to be a potential drug for the treatment of chagas' disease. violacein is also effective against leukemia and lymphoma cells in culture (ic50 10(-8) m). changes in the nuclear acid content, 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide reduction and neutral red uptake in these cells were used to evaluate the cytotoxicity of violacein in v79 chinese hamster (m-8) fibroblasts. violacein was highly cytotoxic to ...200011149754
chromobacteriosis in a chinese red panda (ailurus fulgens styani).an adult chinese red panda (ailurus fulgens styani) transported by airplane from florida to a north dakota zoo died 1 week after arrival. grossly, an interscapular abscess, subcutaneous inflammation, lymphadenitis, and pulmonary abscesses were observed. microscopic findings included necrotizing inflammation in liver, lung, lymph node, and spleen. chromobacterium violaceum was cultured from the interscapular abscess, liver, lung, and spleen and was injected into swiss webster mice. these mice die ...200010730953
extraction of violacein from chromobacterium violaceum provides a new quantitative bioassay for n-acyl homoserine lactone autoinducers.fatty acyl homoserine lactones (ahls) are used as extracellular quorum sensing signals by a variety of gram-negative bacteria. by activating proteins belonging to the luxr family of transcriptional regulators, these signal metabolites allow population density-dependent gene regulation within a species, as well as interspecies communication among different bacteria. the experimental detection of ahls is important in the identification of quorum sensing capabilities in bacteria. chromobacterium vi ...200010739342
mechanism, regulation, and ecological role of bacterial cyanide biosynthesis.a few bacterial species are known to produce and excrete hydrogen cyanide (hcn), a potent inhibitor of cytochrome c oxidase and several other metalloenzymes. in the producer strains, hcn does not appear to have a role in primary metabolism and is generally considered a secondary metabolite. hcn synthase of proteobacteria (especially fluorescent pseudomonads) is a membrane-bound flavoenzyme that oxidizes glycine, producing hcn and co2. the hcnabc structural genes of pseudomonas fluorescens and p. ...200010763748
intrinsic conformation of lipid a is responsible for agonistic and antagonistic activity.lipopolysaccharides (lps, endotoxin) represent a major virulence factor of gram-negative bacteria, which can cause septic shock in mammals, including man. the lipid anchor of lps to the bacterial outer membrane, lipid a, exhibits a peculiar chemical structure, harbours the 'endotoxic principle' of lps and is also responsible for the expression of pathophysiological effects. chemically modified lipid a can be endotoxically inactive, but may express strong antagonistic activity against endotoxical ...200010806403
chromobacterium violaceum infection in brazil. a case report.we report the second case of infection with chromobacterium violaceum that occurred in brazil. a farm worker living in the state of são paulo presented fever and severe abdominal pain for four days. at hospitalization the patient was in a toxemic state and had a distended and painful abdomen. chest x-ray and abdominal ultrasound revealed bilateral pneumonia and hypoechoic areas in the liver. the patient developed failure of multiple organs and died a few hours later. blood culture led to isolati ...200010810326
plants secrete substances that mimic bacterial n-acyl homoserine lactone signal activities and affect population density-dependent behaviors in associated gram-negative bacteria, many important changes in gene expression and behavior are regulated in a population density-dependent fashion by n-acyl homoserine lactone (ahl) signal molecules. exudates from pea (pisum sativum) seedlings were found to contain several separable activities that mimicked ahl signals in well-characterized bacterial reporter strains, stimulating ahl-regulated behaviors in some strains while inhibiting such behaviors in others. the chemical nature of the active mimic com ...200010830263
chromobacterium violaceum diarrhea.this is the first case of chromobacterium violaceum diarrhoea from coastal karnataka reported in a 2 year 10 months old girl. stool culture yielded chromobacterium violaceum and was sensitive to ampicillin, gentamicin, chloramphenicol, erythromycin and septran. patient completely recovered with ampicillin and gentamicin.200010885215
fatty acid steryl, stanyl, and steroid esters by esterification and transesterification in vacuo using candida rugosa lipase as catalyst.sterols (sitosterol, cholesterol, stigmasterol, ergosterol, and 7-dehydrocholesterol) and sitostanol have been converted in high to near-quantitative yields to the corresponding long-chain acyl esters via esterification with fatty acids or transesterification with methyl esters of fatty acids or triacylglycerols using lipase from candida rugosa as biocatalyst in vacuo (20-40 mbar) at 40 degrees c. neither organic solvent nor water is added in these reactions. under similar conditions, cholestero ...200111170561
acyl-homoserine lactone production is more common among plant-associated pseudomonas spp. than among soilborne pseudomonas spp.a total of 137 soilborne and plant-associated bacterial strains belonging to different pseudomonas species were tested for their ability to synthesize n-acyl-homoserine lactones (nahl). fifty-four strains synthesized nahl. interestingly, nahl production appears to be more common among plant-associated than among soilborne pseudomonas spp. indeed, 40% of the analyzed pseudomonas syringae strains produced nahl which were identified most often as the short-chain nahl, n-hexanoyl-l-homoserine lacton ...200111229911
methods for detecting acylated homoserine lactones produced by gram-negative bacteria and their application in studies of ahl-production the process of evaluating the role of acylated homoserine lactones (ahls) in food-spoiling gram-negative bacteria, we have combined a range of bacterial ahl monitor systems to determine the ahl-profile and the kinetics of ahl-production. ahl production from 148 strains of enterobacteriaceae isolated from foods was tested using escherichia coli psb403 (luxr), agrobacterium tumefaciens a136 (trar) and both induction and inhibition of chromobacterium violaceum cv026 (cvir). all strains except on ...200111240047
successful treatment of an infant with chromobacterium violaceum sepsis.chromobacterium violaceum sepsis, a rarely reported phenomenon, has a high mortality rate. we report a unique case of c. violaceum sepsis in an infant. a 4-month-old girl presented to our institution with fever, pustular skin lesions, and distended abdomen, as well as diminished activity and mental status. radiological investigation revealed brain, lung, and hepatic abscesses. the infant was successfully treated with trimethoprim-sulfamethoxazole and ciprofloxacin.200111247733
expression and partial characterization of an elastase from chromobacterium violaceum.chromobacterium violaceum was recovered at necropsy from the lungs, liver, spleen, and an interscapular abscess of a chinese red panda (strain 98-9187) [j. vet. diagn. invest. 12 (2000) 177]. as the lungs exhibited extensive, necrotizing lesions harboring bacterial aggregates, we sought to determine whether c. violaceum produced an elastase that might in part account for these lesions. the c. violaceum type strain (atcc 12472(t)) and strain 98-9187 were shown to exhibit elastolytic activity by e ...200111278124
detection and characterization of quorum sensing signal molecules in acinetobacter strains.quorum sensing is a widespread regulatory mechanism among gram-negative bacteria. in this study, acinetobacter strains were assayed for the presence of quorum sensing signal molecules capable of activating n-acylhomoserine lactone biosensors. by using an agrobacterium tumefaciens reporter strain it was shown that all the cultures produced two to four detectable signal molecules with different chromatographic patterns. in a. calcoaceticus bd413 supernatants four compounds were detected in a time- ...200111297357
molecular basis for enantioselectivity of lipase from chromobacterium viscosum toward the diesters of 2,3-dihydro-3-(4'-hydroxyphenyl)-1,1,3-trimethyl-1h-inden-5-ol.2,3-dihydro-3-(4'-hydroxyphenyl)-1,1,3-trimethyl-1h-inden-5-ol, 1, is a chiral bisphenol useful for preparation of polymers. previous screening of commercial hydrolases identified lipase from chromobacterium viscosum (cvl) as a highly regio- and enantioselective catalyst for hydrolysis of diesters of 1. the regioselectivity was > or =30:1 favoring the ester at the 5-position, while the enantioselectivity varied with acyl chain length, showing the highest enantioselectivity (e = 48 +/- 20 s) for ...200111325269
gene synthesis, expression in e. coli, and in vitro refolding of pseudomonas sp. kwi 56 and chromobacterium viscosum lipases and their chaperones.pseudomonas lipases are industrially used as detergent additives, in the food industry, and in organic synthesis. currently, these lipases are either isolated from wild-type strains or overexpressed in recombinant pseudomonas host strains which may be subject to special safety regulations and thus be unsuitable for enzyme engineering via directed evolution. here we describe the heterologous expression of two pseudomonas lipases in escherichia coli. the lipase genes of pseudomonas sp. kwi 56 (rec ...200111330714
biodegradation of poly(tetramethylene succinate-co-tetramethylene adipate) and poly(tetramethylene succinate) through water-soluble products.poly(tetramethylene succinate-co-tetramethylene adipate) (pbsa) and poly(tetramethylenesuccinate) (pbs) were hydrolyzed experimentally into water-soluble oligomers and monomers by chromobacterium extracellular lipase. the oligomers were identified by high-performance liquid chromatography-mass spectrometry and 1h-nuclear magnetic resonance, which indicated that a total of 28 oligomer species were liberated from pbsa, and that 13 of them were identical to the hydrolysates from pbs. moreover, 20 o ...200111337881
alginate as a macroaffinity ligand and an additive for enhanced activity and thermostability of lipases.lipases are being employed increasingly for the synthesis of drug intermediates and pharmaceutically important molecules as well as for the resolution of racemic mixtures for obtaining physiologically active enantiomers. alginate was used as a macroaffinity ligand to purify lipases from chromobacterium viscosum, porcine pancreas and wheatgerm by employing the technique of affinity precipitation. in all the cases, the purified preparation showed a single band on sds/page. the process gave adequat ...200111389669
biogenic production of cyanide and its application to gold recovery.chromobacterium violaceum is a cyanogenic (cyanide-producing) microorganism. cyanide is used on an industrial scale to complex and recover gold from ores or concentrates of ores bearing the precious metal. a potentially useful approach in gold mining operations could be to produce cyanide biologically in relatively small quantities at the ore surface. in this study, c. violaceum grown in nutrient broth formed a biofilm and could complex and solubilize 100% of the gold on glass test slides within ...200111420652
reaction of acylated homoserine lactone bacterial signaling molecules with oxidized halogen antimicrobials.oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. this study was conducted to investigate the potential for oxidized halogens to react with ...200111425738
production of n-acyl homoserine lactones by gram-negative bacteria isolated from contact lens wearers.the purpose of this study was to investigate the production of n-acyl-homoserine lactone (ahl) signal molecules in ocular gram-negative bacteria. a total of 91 ocular strains isolated from contact lens adverse response patients and asymptomatic subjects were used in the study. these included acinetobacter, aeromonas hydrophila, escherichia coli, haemophilus influenzae, klebsiella oxytoca, pseudomonas aeruginosa, serratia liquefaciens, serratia marcescens, and stenotrophomonas maltophilia. the bi ...200111446456
a second quorum-sensing system regulates cell surface properties but not phenazine antibiotic production in pseudomonas aureofaciens.the root-associated biological control bacterium pseudomonas aureofaciens 30-84 produces a range of exoproducts, including protease and phenazines. phenazine antibiotic biosynthesis by phzxyfabcd is regulated in part by the phzr-phzi quorum-sensing system. mutants defective in phzr or phzi produce very low levels of phenazines but wild-type levels of exoprotease. in the present study, a second genomic region of strain 30-84 was identified that, when present in trans, increased beta-galactosidase ...200111526037
antileishmanial activity of the violacein extracted from chromobacterium violaceum. 200111533018
violacein biotransformation by basidiomycetes and bacteria.the biotransformation study of the pigment (violacein) produced by chromobacterium violaceum, was verified by its decolorization utilizing six different organisms in liquid and solid media.200111559408
[pleural empyema caused by flavimonas oryzihabitans in a healthy male]. 200111562334
chromobacterium violaceum: a review of pharmacological and industiral perspectives.violet-pigmented bacteria, which have been described since the end of the 19th century, are occasionally the causative agent of septicemia and sometimes cause fatal infection in human and animals. bacteria, producing violet colonies due to the production of a nondiffusible pigment violacein, were classified as a redefined genus chromobacterium. chromobacterium violaceum is gram-negative, and saprophyte from soil and water is normally considered nonpathogenic to human, but is an opportunistic pat ...200111596879
laribacter hongkongensis gen. nov., sp. nov., a novel gram-negative bacterium isolated from a cirrhotic patient with bacteremia and empyema.a bacterium was isolated from the blood and empyema of a cirrhotic patient. the cells were facultatively anaerobic, nonsporulating, gram-negative, seagull shaped or spiral rods. the bacterium grows on sheep blood agar as nonhemolytic, gray colonies 1 mm in diameter after 24 h of incubation at 37 degrees c in ambient air. growth also occurs on macconkey agar and at 25 and 42 degrees c but not at 4, 44, and 50 degrees c. the bacterium can grow in 1 or 2% but not 3, 4, or 5% nacl. no enhancement of ...200111724825
development of small-size tubular-flow continuous reactors for the analysis of operational stability of enzymes in low-water systems.a very small-scale continuous flow reactor has been designed for use with enzymes in organic media, particularly for operational stability studies. it is constructed from fairly inexpensive components, and typically uses 5 mg of catalyst and flow rates of 1 to 5 ml/h, so only small quantities of feedstock need to be handled. the design allows control of the thermodynamic water activity of the feed, and works with temperatures up to at least 80 degrees c. the reactor has been operated with both n ...200111114661
enzyme immobilization in silica-hardened this study we describe a novel method for immobilizing enzymes in a solid nanocomposite matrix based on gelatin gels, which are subsequently hardened by in situ polymerization of tetraethoxysilane (teos). chromobacterium viscosum lipase is taken as the example. this immobilization method possesses the advantages of enzyme entrapment in microemulsions, together with newly beneficial qualities, such as transparency, which permits direct spectroscopic investigation, and considerable mechanical s ...200111114662
effect of hydrocarbon-water interfaces on synthetic and hydrolytic activities of lipases.we have developed a new method of lipase activation for interesterification, in which lipase, in contact with a hydrocarbon-water interface, has been found to have high interesterification activity in an anhydrous solvent. we have applied this activation method to various lipase and obtained high synthetic activity in n-hexane, and have investigated the effect of various hydrocarbon-water interfaces on the synthetic and hydrolytic activities of lipases. the esterification and/or interesterificat ...200116233091
important unusual infections in australia: a critical care review a number of the important unusual infections in australia that can lead to critical illness.200116573516
molecular cloning and expression of mn(2+)-dependent sphingomyelinase/hemolysin of an aquatic bacterium, pseudomonas sp. strain tk4.we report here the molecular cloning and expression of a hemolytic sphingomyelinase from an aquatic bacterium, pseudomonas sp. strain tk4. the sphingomyelinase gene was found to consist of 1,548 nucleotides encoding 516 amino acid residues. the recombinant 57.7-kda enzyme hydrolyzed sphingomyelin but not phosphatidylcholine, phosphatidylserine, phosphatidylglycerol, phosphatidic acid, or phosphatidylethanolamine, indicating that the enzyme is a sphingomyelin-specific sphingomyelinase c. the hydr ...200211751833
histone deacetylase inhibitor fk228 inhibits tumor angiogenesis.fk228 (formerly fr901228) was recently isolated from chromobacterium violaceum as a potent antitumor agent and its biologic target protein was identified as histone deacetylase (hdac). because of its unique chemical structure (i.e., bicyclic depsipeptide) and activity profile in the national cancer institute's developmental therapeutics program, fk228 is currently in a phase i clinical trial for cancer therapy. in the present study, we investigated the antiangiogenic activity of fk228 in vivo an ...200211774279
chromobacterium violaceum infection: a rare but frequently fatal disease.the authors report a rare case of chromobacterium violaceum infection in a 2-month-old child. she presented with an apparently localized abscess, which appeared to respond well to therapy. however, the infection recurred later with a fulminant course. the organism frequently is dismissed as a contaminant or not identified properly, and the fatality rates are high. a high degree of awareness about this infection needs to be created, especially among pediatricians and pediatric surgeons, because c ...200211781998
a comparison of lipase-catalysed ester and lactone synthesis in low-water systems: analysis of optimum water activity.we investigated the effects of the lyophilisation medium (enzyme plus buffer salt and additives) and of water activity (a(w)) on the catalytic properties of lipase from chromobacterium viscosum (lipase cv) in organic solvents; catalysis of ester and lactone synthesis were compared and, despite the similarities of the reactive groups involved in these reactions, some interesting differences were observed. including 2-[n-morpholino]ethanesulfonic acid (mes) buffer in the lyophilisation medium of l ...200211807759
characterization of n-acyl homoserine lactone overproducing mutants of burkholderia multivorans atcc 17616.burkholderia multivorans atcc 17616 ordinarily produces insufficient amounts of n-acyl homoserine lactones (ahls) to promote ahl-dependent formation of the pigment violacein by the reporter strain chromobacterium violaceum cv026. we have isolated ahl-overproducing mutants of strain 17616 by screening for variants which do cross-feed ahls to strain cv026. nucleotide-sequence analysis of the bmuir locus which specifies ahl synthase (bmui) and ahl-binding transcriptional activator protein (bmur) in ...200211814664
synthesis of monoacyl a-ring precursors of 1alpha,25-dihydroxyvitamin d3 through selective enzymatic efficient synthesis of monoacylated 1alpha,25-dihydroxyvitamin d3 a-ring precursors 15, 16, 18, and 19 has been described through an enzymatic hydrolysis process. candida antarctica a lipase (cal-a) hydrolyzes the c-5 acetate ester in trans stereoisomers 9 and 13, with complete and high selectivity, respectively. in the case of cis isomers 11 and 14, chromobacterium viscosum lipase (cvl) is the enzyme of choice, exhibiting opposite selectivity for these two enantiomers. this lipase selectivel ...200211846672
fluorescent inhibitors reveal solvent-dependent micropolarity in the lipid binding sites of lipases.triacylglycerol analogue p-nitrophenyl phosphonates specifically react with the active-site serine of lipolytic enzymes to give covalent lipase-inhibitor complexes, mimicking the first transition state which is involved in lipase-mediated ester hydrolysis. here we report on a new type of phosphonate inhibitors containing a polarity-sensitive fluorophore to monitor micropolarity around the active site of the enzyme in different solvents. the respective compounds are hexyl and methyl dimethylamino ...200212009403
[synthesis of signaling n-acyl-homoserine-lactones participating in quorum sensing in rhizosphere and soil bacteria pseudomonas and xanthomonas].signaling molecules assigned to n-acyl-homoserine-lactones (ahl) serve as autoinducers for the genes controlling the quorum sensing regulatory system. in many gram-negative bacteria, ahl are the key factors responsible for density-dependent regulation of exoenzyme and secondary metabolite production; they also participate in interaction between bacteria and higher organisms. the soil and rhisosphere bacteria pseudomonas and xanthomonas from different geographical zones of russia and the former u ...200212018176
chromobacterium violaceum septicemia.chromobacterium violaceum is an extremely rare human pathogen. we report a rare case of septicemia with multiple abscesses and otitis media in a newborn caused by chromobacterium violaceum.200212019559
building blocks for the solution phase synthesis of oligonucleotides: regioselective hydrolysis of 3',5'-di-o-levulinylnucleosides using an enzymatic approach.a short and convenient synthesis of 3'- and 5'-o-levulinyl-2'-deoxynucleosides has been developed from the corresponding 3',5'-di-o-levulinyl derivatives by regioselective enzymatic hydrolysis, avoiding several tedious chemical protection/deprotection steps. thus, candida antartica lipase b (cal-b) was found to selectively hydrolyze the 5'-levulinate esters, furnishing 3'-o-levulinyl-2'-deoxynucleosides 3 in >80% isolated yields. on the other hand, immobilized pseudomonas cepacia lipase (psl-c) ...200212076150
[bromo- and iodo-containing alkaloids from marine microorganisms and sponges].the taxonomic distribution, structure, and biological activity of halogenated alkaloids isolated from marine microorganisms and sponges are reviewed. the structures of nearly 140 natural bromo- and iodo-containing alkaloids are shown.200212077845
structural comparison of bacterial and human iron-dependent phenylalanine hydroxylases: similar fold, different stability and reaction rates.structure determination of bacterial homologues of human disease-related proteins provides an efficient path to understanding the three-dimensional fold of proteins that are associated with human diseases. however, the precise locations of active-site residues are often quite different between bacterial and human versions of an enzyme, creating significant differences in the biological understanding of enzyme homologs. to study this hypothesis, phenylalanine hydroxylase from a bacterial source h ...200212096915
effect of medium composition, flow rate, and signaling compounds on the formation of soluble extracellular materials by biofilms of chromobacterium violaceum.biofilms of the homoserine-lactone-defective strain chromobacterium violaceum cv026 were grown on silicone surfaces in a flow chamber. the effect of medium flow rate, different levels of n-butanoyl-homoserine lactone, and nutrients on biofilm activity was studied by quantifying the proteins and exopolysaccharides attached to the cells. to compare the effect of each of the three variables within a wide range, the experiments were designed as a full factorial search with three levels for each vari ...200212111158
characterization of a new efflux pump, mexghi-opmd, from pseudomonas aeruginosa that confers resistance to vanadium.vanadium has an antibacterial activity against pseudomonas aeruginosa, especially under conditions of iron limitation. some degree of resistance to v is inducible by prior exposure to the metal. one mutant (vs1) with a higher sensitivity to v was obtained by transposon mutagenesis of p. aeruginosa pa 59.20, a clinical isolate. this mutant had an insertion in a non-coding region, upstream of a cluster of four genes. three of them show similarities to genes corresponding to known p. aeruginosa ant ...200212177331
chromobacterium violaceum: a case of diarrhea in senegal.a 5-year-old infant with diarrhea had heavy growth of chromobacterium violaceum cultured from stool. this organism is restricted geographically between latitudes 35 degrees n and 35 degrees s. it can cause sepsis and various focal infections but is not a well-known cause of diarrhea.200212182388
chromobacterium violaceum infection in children: a case of fatal septicemia with nasopharyngeal abscess and literature review.this previously healthy 5-year-old boy initially presented with fever and purulent conjunctivitis. the course evolved rapidly into preseptal and facial cellulitis, nasopharyngeal abscess and sepsis. chromobacterium violaceum was isolated from conjunctival exudate and blood cultures. he received intravenous cefazolin therapy for 2 days, followed by penicillin, oxacillin and netilmicin. however, no improvement was noted, and he died on the fifth days of illness.200212237610
crystal structure of a thermostable lipase from bacillus stearothermophilus p1.we describe the first lipase structure from a thermophilic organism. it shares less than 20% amino acid sequence identity with other lipases for which there are crystal structures, and shows significant insertions compared with the typical alpha/beta hydrolase canonical fold. the structure contains a zinc-binding site which is unique among all lipases with known structures, and which may play a role in enhancing thermal stability. zinc binding is mediated by two histidine and two aspartic acid r ...200212417199
a phase i trial of depsipeptide (fr901228) in patients with advanced cancer.depsipeptide (fr901228) is a bicyclic peptide isolated from chromobacterium violaceum that has demonstrated potent in vitro cytotoxic activity against human tumor cell lines and in vivo efficacy against human tumor xenografts. the primary mechanism of action is through inhibition of histone deacetylase. initial development was halted due to significant cardiac toxicity. subsequent studies performed at the national cancer institute demonstrated administration without cardiotoxicity was possible b ...200212440223
degradation of aliphatic polyester films by commercially available lipases with special reference to rapid and complete degradation of poly(l-lactide) film by lipase pl derived from alcaligenes sp.commercial lipases were examined for their degradation efficiency of aliphatic polyester films. in 100 days immersion of polyester films in lipase solutions at 37 degrees c at ph 7.0, lipase asahi derived from chromobacterium viscosum degraded polybutylene succinate-co-adipate (pbsa), poly (e-caprolactone) (pcl) and polybutylene succinate (pbs), and lipase f derived from rhizopus niveus degraded pbsa and pcl during 4-17 days. lipase f-ap15 derived from rhizopus orizae could degrade pbsa in 22 da ...200212449316
order of substrate binding in bacterial phenylalanine hydroxylase and its mechanistic implication for pterin-dependent oxygenases.phenylalanine hydroxylase (pah) is a pterin-dependent non-heme metalloenzyme that catalyzes the oxidation of phenylalanine to tyrosine, which is the rate-limiting step in the catabolism of phe. chromobacterium violaceum phenylalanine hydroxylase (cpah) has been prepared and its steady-state mechanism has been investigated. the enzyme requires iron for maximal activity. initial rate measurements, done in the presence of the 6,7-dimethyl-5,6,7,8-tetrahydropterin (dmph(4)) cofactor, yielded an aver ...200312459906
phagocyte nadph oxidase, but not inducible nitric oxide synthase, is essential for early control of burkholderia cepacia and chromobacterium violaceum infection in mice.reactive oxygen and nitrogen intermediates have critical, partially overlapping roles in host defense against a variety of pathogens. using mice deficient in generating phagocyte superoxide (p47(phox)(-/-)) and mice deficient in generating inducible nitric oxide synthase (inos(-/-)), we examined the roles of these reactive species in host defense against burkholderia cepacia and chromobacterium violaceum, organisms known to have unusual virulence in chronic granulomatous disease. intraperitoneal ...200312496167
violacein and its beta-cyclodextrin complexes induce apoptosis and differentiation in hl60 cells.violacein, a pigment isolated from chromobacterium violaceum, has been reported to have multiple biological activities including in vitro antitumor effects. certain anticancer agents are known to induce apoptosis in human tumor cell lines. in this work, our aim was to investigate the effectiveness of violacein/beta-cyclodextrin (beta-cd)-containing systems to produce lethal effects in the human promyelocytic leukemia cell line hl60. using the mtt tetrazolium reduction test, ic(50) for the inclus ...200312628314
pcr-assisted contig extension: stepwise strategy for bacterial genome closure.finishing is rate limiting for genome projects, and improvements in the efficiency of complete genome-sequence compilation will require improved protocols for gap closure. here we report a novel approach for extending shotgun contigs and closing gaps that we termed pcr-assisted contig extension (pace). pace depends on the capture of rare mismatched interactions that occur between arbitrary primers and template dna of unknown sequence, even under highly stringent conditions, by means of elevated ...200312661167
picosecond dynamics of a peptide from the acetylcholine receptor interacting with a neurotoxin probed by tailored tryptophan fluorescence.a tryptophan analog, dehydro-n-acetyl-l-tryptophanamide (delta-nata), which is produced enzymatically via l-tryptophan 2',3'-oxidase from chromobacterium violaceum, is newly used for time-resolved fluorescence. the absorption and emission maxima of delta-nata at 332 and 417 nm, respectively, in 20% dimethylformamide-water are significantly shifted to the red with respect to those of tryptophan in water, permitting us to measure its fluorescence in the presence of tryptophan residues. we demonstr ...200312785053
fatal septicaemia caused by chromobacterium violaceum.we report a case of chromobacterium violaceum septicaemia in a 10-year old boy admitted to hospital in september 2001, two weeks after he suffered a crush injury of the left foot. in spite of surgical debridement and antibiotics his condition worsened and he developed multiple liver and lung abscesses. he died one week after admission and a blood culture grew chromobacterium violaceum.200312795018
[the inhibitory effect of extracts from galla chinensis on marine fouling bacteria].to observe the activity of extracts from galla chinensis with different solvents against marine fouling bacteria in vitro.200312795221
ym-254890, a novel platelet aggregation inhibitor produced by chromobacterium sp. qs3666.a novel platelet aggregation inhibitor, ym-254890, was isolated from the culture broth of strain qs3666. this strain was isolated from a soil sample collected at okutama, tokyo, japan, and was identified as chromobacterium sp. by morphological and physiological criteria. ym-254890 was purified from the culture supernatant by solvent extraction, ods and silica gel flash chromatography, followed by preparative hplc. ym-254890 inhibited adp-induced platelet aggregation in human platelet-rich plasma ...200312817809
chromobacterium violaceum bacteremia: a case report.chromobacterium violaceum is confined in tropical and subtropical regions, which can cause life-threatening disease. it is the only chromobacterium species that is pathogenic to humans. because of its rarity, clinicians often do not appreciate its importance when it is isolated. we report a fulminate fatal case of c. violaceum bacteremia in a 20-year-old male taiwanese. the clinical manifestations were fever and abdominal pain, followed by shock and pulmonary septic embolism. emergent laparotomy ...200312886967
novel bacteria degrading n-acylhomoserine lactones and their use as quenchers of quorum-sensing-regulated functions of plant-pathogenic bacteria.bacteria degrading the quorum-sensing (qs) signal molecule n-hexanoylhomoserine lactone were isolated from a tobacco rhizosphere. twenty-five isolates degrading this homoserine lactone fell into six groups according to their genomic rep-pcr and rrs pcr-rflp profiles. representative strains from each group were identified as members of the genera pseudomonas, comamonas, variovorax and rhodococcus: all these isolates degraded n-acylhomoserine lactones other than the hexanoic acid derivative, albei ...200312904538
production of n-acylhomoserine lactone signal molecules by gram-negative soil-borne and plant-associated bacteria.quorum-sensing control mediated by n-acylhomoserine lactone (ahl) signal molecules has been established as a key feature in the regulation of various metabolic traits in many bacteria. approximately 300 strains representing 6 genera and 18 species of soil-borne and plant-associated gram-negative bacteria isolated in various regions of the former ussr using two reporter systems were screened for ahl production. the production was observed in 17.5% of the screened bacterial strains. positive respo ...200315058194
the complete genome sequence of chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability.chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) approximately 500 orfs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) widespread utilization of quorum sensing for control of inducible systems, all of ...200314500782
improvement in enzyme activity and stability by addition of low molecular weight polyethylene glycol to sodium bis(2-ethyl-l-hexyl)sulfosuccinate/isooctane reverse micellar system.the activity and stability of chromobacterium viscosum lipase (glycerolester hydrolase, ec olive oil hydrolysis in sodium bis (2-ethyl-l-hexyl)sulfosuccinate (aot)/isooctane reverse micelles is increased appreciably when low molecular weight polyethylene glycol (peg 400) is added to the reverse micelles. to understand the effect of peg 400 on the phase behavior of the reverse micellar system, the phase diagram of aot/ peg 400/water/isooctane system was studied. the influences ...200314515025
production of acylated homoserine lactones by different serotypes of vibrio anguillarum both in culture and during infection of rainbow trout.onehundred and forty-eight out of onehundred and fifty strains of vibrio anguillarum isolated from vibriosis in danish marine aquaculture produced bacterial communication signals, acylated homoserine lactones, eliciting a response in the agrobacterium tumefaciens (pzlr4) monitoring system. one strain, a serotype o4, induced a strong response in the chromobacterium violaceum (cv026) monitoring system. profiles of ahls determined by tlc separation revealed the presence of at least four ahls and a ...200314529176
cytotoxicity and potential antiviral evaluation of violacein produced by chromobacterium violaceum.natural products are an inexhaustible source of compounds with promising pharmacological activities including antiviral action. violacein, the major pigment produced by chromobacterium violaceum, has been shown to have antibiotic, antitumoral and anti-trypanosoma cruzi activities. the goal of the present work was to evaluate the cytotoxicity of violacein and also its potential antiviral properties. the cytotoxicity of violacein was investigated by three methods: cell morphology evaluation by inv ...200314595466
lipase-catalyzed kinetic resolution on solid-phase via a "capture and release" strategy.the lipase-catalyzed kinetic resolution of (r/s)-3-phenylbutyric acid 2 using solid-supported cyclohexane-1,3-dione (chd) 6 is described. in each case the predominant enantiomer observed, after cleavage from the resin, was (r)-(-)-3-phenylbutyric acid (r)-2 (ee > 99%) rather than the expected (s)-enantiomer of 2. this observation is in contrast to the fact that chromobacterium viscosum lipase shows high enantiospecificity for the (s)-enantiomer in the corresponding solution-phase hydrolysis reac ...200314611219
multidrug resistant chromobacterium violaceum: an unusual bacterium causing long standing wound abscess. 200317643028
n-hexanoyl-l-homoserine lactone, a mediator of bacterial quorum-sensing regulation, exhibits plant-dependent stability and may be inactivated by germinating lotus corniculatus seedlings.the half-life of n-hexanoyl-l-homoserine lactone (c6-hsl) was determined under various ph and temperature conditions, and in several plant environments. c6-hsl was sensitive to alkaline ph, a process that was also temperature-dependent. in addition, c6-hsl disappeared from plant environments, i.e. axenic monocot and dicot plants cultivated under gnotobiotic, hydroponic conditions, albeit with variable kinetics. the disappearance was rapid at the root system of legume plants such as clover or lot ...200416329888
a new method of synthesis and antibacterial activity evaluation of piper amides.several natural piper amides and their mimics were synthesized by developing a new strategy of amide formation. the piper amides were tested against both gram +ve and gram -ve bacterial strains and found that they are particularly more active against staphylococcus aureus and chromobacterium violaceum strains.200414974622
role of the second coordination sphere residue tyrosine 179 in substrate affinity and catalytic activity of phenylalanine hydroxylase.phenylalanine hydroxylase converts phenylalanine to tyrosine utilizing molecular oxygen and tetrahydropterin as a cofactor, and belongs to the aromatic amino acid hydroxylases family. the catalytic domains of these enzymes are structurally similar. according to recent crystallographic studies, residue tyr179 in chromobacterium violaceum phenylalanine hydroxylase is located in the active site and its hydroxyl oxygen is 5.1 a from the iron, where it has been suggested to play a role in positioning ...200414999516
impact of violacein-producing bacteria on survival and feeding of bacterivorous nanoflagellates.we studied the role of bacterial secondary metabolites in the context of grazing protection against protozoans. a model system was used to examine the impact of violacein-producing bacteria on feeding rates, growth, and survival of three common bacterivorous nanoflagellates. freshwater isolates of janthinobacterium lividum and chromobacterium violaceum produced the purple pigment violacein and exhibited acute toxicity to the nanoflagellates tested. high-resolution video microscopy revealed that ...200415006783
pathogenomics of non-pathogens.analysing the genomes of non-pathogenic microorganisms, in addition to its basic and applied scientific interest, can also shed considerable light on the study of pathogenic microorganisms. two of the three microorganisms described here are rarely pathogenic, but carry genetic determinants that have previously been identified as being important for the pathogenicity of other microorganisms. this underlines the growing understanding that many so-called 'virulence genes' are probably involved in m ...200415040257
a very rare and rapidly fatal case of chromobacterium violaceum septicemia.chromobacterium violaceum infection is rare but causes a high mortality rate particularly in immunosuppressed persons. since its clinical presentation is non-specific and the diagnosis basically relies upon blood culture and sensitivity, this infection should be considered among the organisms targeted empirically for antibiotic therapy when a cellulitis or rapidly progressive illness follows exposure to water or soil. this is a case of fulminant septicemia caused by this rarely encountered organ ...200415779589
microbial genomics: tropical treasure?a brazilian consortium has unveiled the genomic dna sequence of the purple-pigmented bacterium chromobacterium violaceum, a dominant component of the tropical soil microbiota. the sequence provides insight into the abundant potential of this organism for biotechnological and pharmaceutical applications.200414738751
characterisation of steryl esterase activities in commercial lipase preparations.triglycerides, steryl esters, resin acids, free fatty acids and sterols are lipophilic extractives of wood (commonly referred to as pitch or wood resin) and have a negative impact on paper machine runnability and quality of paper. thus, enzymes capable of modifying these compounds would be potential tools for reducing pitch problems during paper manufacture. in this work, 19 commercial lipase preparations were tested for their ability to degrade steryl esters, which may play a significant role i ...200414741769
toward pku enzyme replacement therapy: pegylation with activity retention for three forms of recombinant phenylalanine hydroxylase.phenylketonuria (pku) is a disease in which phenylalanine and phenylalanine-derived metabolites build up to neurotoxic levels due to mutations in the phenylalanine hydroxylase gene (pah). enzyme replacement therapy is a viable option to supply active pah. however, the inherent protease sensitivity and potential immunogenicity of pah have precluded adoption of this approach. in this report, we have used polyethylene glycol derivatization (pegylation) to produce protected forms of pah for potentia ...200414741785
a new set of bioinformatics tools for genome projects.a new tool called system for automated bacterial integrated annotation--sabia (sabia being a very well-known bird in brazil) was developed for the assembly and annotation of bacterial genomes. this system performs automatic tasks of assembly analysis, orfs identification/analysis, and extragenic region analyses. genome assembly and contig automatic annotation data are also available in the same working environment. the system integrates several public domains and newly developed software program ...200415100986
closure of rrna related gaps in the chromobacterium violaceum genome with the pcr-assisted contig extension (pace) the finishing phase of the chromobacterium violaceum genome project, the shotgun sequences were assembled into 57 contigs that were then organized into 19 scaffolds, using the information from shotgun and cosmid clones. among the 38 ends resulting from the 19 scaffolds, 10 ended with sequences corresponding to rrna genes (seven ended with the 5s rrna gene and three ended with the 16s rrna gene). the 28 non-ribosomal ends were extended using the pcr-assisted contig extension (pace) methodology ...200415100987
gene expression in chromobacterium violaceum.the repertoire of 4,431 open reading frames (orfs), eight rrna operons and 98 trna genes of chromobacterium violaceum must be expressed in a regulated manner for successful adaptation to a wide variety of environmental conditions. to accomplish this feat, the organism relies on protein machineries involved in transcription, rna processing and translation. analysis of the c. violaceum genome showed that transcription initiation, elongation and termination are performed by the five well-known rna ...200415100988
bacteriophages and insertion sequences of chromobacterium violaceum atcc 12472.a fluid genome is a great advantage to prokaryotes, enabling quick adaptation to various types of ecological niches and to diverse environmental selective pressures. a substantial portion of these sudden changes is mediated by lateral gene transfer (lgt), through genetic recombination mechanisms, such as transformation, conjugation and transduction. the recent sequencing of several organisms has offered a new approach to the study of lgt, using comparison and analysis of nucleotide sequences dis ...200415100989
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