TitleAbstractYear(sorted descending)
[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
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
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
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
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
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
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
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
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
inhibition of lipases from chromobacterium viscosum and rhizopus oryzae by tetrahydrolipstatin.tetrahydrolipstatin is known as an inhibitor for pancreatic lipase but not for microbial lipases. in this paper we demonstrate that in the presence of water-insoluble substrates like tributyrin or olive oil, tetrahydrolipstatin inhibits the lipases of chromobacterium viscosum and rhizopus oryzae, although with different potency. in contrast to porcine pancreatic lipase, which forms an irreversible and covalent enzyme-inhibitor complex with tetrahydrolipstatin, the inhibition of the microbial lip ...19989461253
preliminary study on hydrophobic interaction chromatography of chromobacterium viscosum lipase on polypropylene glycol immobilized on sepharose.the purification of chromobacterium viscosum lipase was performed using a polypropylene glycol-sepharose gel. the influence of the mobile phase composition on the chromatographic behaviour of chromobacterium viscosum lipase was studied and it was found that the retention of lipase depends on the salt used and increased with ionic strength. using 20% (w/v) ammonium sulphate in the eluent, a total retention of lipase on the column was obtained.19989513291
potential misidentification of burkholderia pseudomallei by api 20ne.biochemical confirmation of the identity of burkholderia pseudomallei in singapore previously relied on the api 20ne panel of tests. after introducing an alternative proprietary biochemical panel, the microbact 24e (medvet, adelaide, australia), we noted that the api panel identified some presumptive b. pseudomallei isolates as other species. we therefore compared the performance of the api 20ne against the microbact 24e with 50 distinct clinical isolates of b. pseudomallei, after 24 hours and a ...19989534210
[infection by chromobacterium violaceum in a patient with acquired immunodeficiency virus infection]. 19989542314
chromobacterium violaceum in tropical northern australia.chromobacterium violaceum is an unusual cause of infection which may have fatality rates of over 60% when systemic illness occurs. we describe four patients infected with this organism who were successfully treated at royal darwin hospital between 1991 and 1996. in tropical australia, c. violaceum infection should be considered along with melioidosis in patients who present with a septic illness with skin lesions and/or organ abscesses after exposure to soil in the wet season.19989577444
chromobacterium violaceum infection.chromobacterium violaceum infection is confined to the tropical and subtropical areas, with almost all reported cases occurring in the southeast. the most common feature of this infection is sepsis, followed by cutaneous involvement and liver abscesses. treatment consists of surgical drainage of purulent collections and appropriate antimicrobial therapy, such as chloramphenicol, gentamicin, imipenem, trimethoprim-sulfamethoxazole, or ciprofloxacin. although c violaceum infection is rare, it is p ...19989598856
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
systematic study of the genus vogesella gen. nov. and its type species, vogesella indigofera comb. nov.a blue-pigmented colony that had a metallic copper-colored sheen was isolated in 1973 from a standard spread plate count preparation of oxidation pond sediment. over the next 11 years, an additional 12 strains of blue-pigmented bacteria were isolated from freshwater samples and compared to several reference strains of bacteria. morphological and biochemical tests revealed that these 13 isolates were very similar to [pseudomonas] indigofera atcc 19706t (t = type strain) and atcc 14036. a numerica ...19978995797
the crystal structure of a triacylglycerol lipase from pseudomonas cepacia reveals a highly open conformation in the absence of a bound inhibitor.. lipases, a family of enzymes which catalyze the hydrolysis of triglycerides, are widely distributed in many organisms. true lipases are distinguished from esterases by the characteristic interfacial activation they exhibit at an oil-water interface. lipases are one of the most frequently used biocatalysts for organic reactions performed under mild conditions. their biotechnological applications include food and oil processing and the preparation of chiral intermediates for the synthesis of ena ...19979032073
the open conformation of a pseudomonas lipase.. the interfacial activation of lipases results primarily from conformational changes in the enzymes which expose the active site and provide a hydrophobic surface for interaction with the lipid substrate. comparison of the crystallization conditions used and the structures observed for a variety of lipases suggests that the enzyme conformation is dependent on solution conditions. pseudomonas cepacia lipase (pcl) was crystallized in conditions from which the open, active conformation of the enzy ...19979032074
quorum sensing in vibrio anguillarum: characterization of the vani/vanr locus and identification of the autoinducer n-(3-oxodecanoyl)-l-homoserine lactone.certain gram-negative pathogens are known to control virulence gene expression through cell-cell communication via small diffusible signal molecules termed autoinducers. this intercellular signal transduction mechanism termed quorum sensing depends on the interaction of an n-acylhomoserine lactone (ahl) auto-inducer molecule with a receptor protein belonging to the luxr family of positive transcriptional activators. vibrio anguillarum is a gram-negative pathogen capable of causing a terminal hem ...19979139920
chemoenzymatic synthesis of chiral biologically active heterocycles.the chemoenzymatic approach to the preparation of some chiral biologically active heterocycles is discussed. synthetic strategies took advantage of enantioselective bioconversion processes carried out on suitable reaction intermediates. reductions of carbonyl compounds catalyzed by different alcohol dehydogenases (tbadh from thermoanaerobium brockii, 20 beta-hsdh from streptomyces hydrogenans, beta-hsdh from pseudomonas testosteroni) allowed the preparation with high enantiomeric purity of the e ...19979274001
case report and review of chromobacterium sepsis--a gram-negative sepsis mimicking melioidosis.chromobacterium violaceum has recently been recognised as a pathogen which can cause life-threatening disease. it is the only chromobacterium species which is pathogenic to humans. due to its unfamiliarity, clinicians often do not appreciate its importance when it is isolated in sterile cultures and may dismiss it as a "containment". it is therefore important for us to be aware of this infection and its clinical spectrum since it is a disease of the tropics. we report a paediatric case of docume ...19979294341
lipase-catalysed resolution of gamma- and delta-lactones.lipase-catalysed stereoselective hydrolysis of a family of saturated gamma- and delta-lactones was investigated. increasing the chain length from delta-octalactone to delta-dodecalactone leads to higher enantiomeric excess. best results were found using a lipase from pseudomonas species (kw51) yielding highest enantiomeric excesses (greater than 99% ee at 50% conversion, e > 100) at short reaction times (10 h) for delta-undecalactone and delta-dodecalactone. in contrast, gamma-lactones were reso ...19979304874
on the inhibition of microbial lipases by tetrahydrolipstatin. 19979309654
chromobacterium violaceum infection of the deep neck tissues in a traveler to thailand. 19979332541
quorum sensing and chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of n-acylhomoserine lactones.quorum sensing relies upon the interaction of a diffusible signal molecule with a transcriptional activator protein to couple gene expression with cell population density. in gram-negative bacteria, such signal molecules are usually n-acylhomoserine lactones (ahls) which differ in the structure of their n-acyl side chains. chromobacterium violaceum, a gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigment violacein. previously the authors described a ...19979421896
biocatalysis using gelatin microemulsion-based organogels containing immobilized chromobacterium viscosum lipase.chromobacterium viscosum (cv) lipase was immobilized in gelatin-containing aerosol-ot (aot) microemulsion-based organogels (mbgs). the behavior of this novel, predominantly hydrophobic matrix as an esterification catalyst has been examined. the biocatalyst was most effective when the mbg was granulated to yield gel particles of approximately 500 mum diameter, providing a total surface area of ca. 10(6) mm(2) per 10 cm(3) of gel. the gel was generally contacted with a solution of the substrate(s) ...199718633956
kinetic studies of chromobacterium viscosum lipase in aot water in oil microemulsions and gelatin microemulsion-based organogels.kinetic studies have shown that octyl decanoate synthesis by chromobacterium viscosum (cv) lipase in sodium bis-2-(ethylhexyl) sulfosuccinate (aot) water in oil (w/o) microemulsions occurs via the nonsequential (ping-pong) bi bi mechanism. there was evidence of single substrate inhibition by decanoic acid at high concentrations. initial rate data yielded estimates for acid and alcohol michaelis constants of ca. 10(-1) mol dm(-3) and a maximum rate under saturation conditions of ca. 10(-3) mol dm ...199718634134
hydrolysis and esterification of acylglycerols and analogs in aqueous medium catalyzed by microbial lipases.the stereoselectivity of microbial lipases from chromobacterium viscosum (cvl) and rhizopus arrhizus (ral) towards monoacylglycerols (rac-1(3)-oleoylglycerol and 2-oleoylglycerol), diacylglycerols (1,3-dioleoylglycerol and rac-1,2(2,3)-dioleoylglycerol) and 2-o-ether analogs (rac-1(3)-oleoyl-2-o-hexadecylglycerol and rac-1(3)-octanoyl-2-o-hexadecylglycerol) was determined. the results of the hydrolysis of 2-o-ether analogs confirmed the importance of the substituent at c-2 of acylglycerols in th ...19968652651
crystal structure of a bacterial lipase from chromobacterium viscosum atcc 6918 refined at 1.6 angstroms resolution.the crystal structure of a lipase from the bacterium chromobacterium viscosum atcc 6918 (cvl) has been determined by isomorphous replacement and refined at 1.6 angstroms resolution to an r-factor of 17.8%. the lipase has the overall topology of an alpha/beta type protein, which was also found for previously determined lipase structures. the catalytic triad of the active center consists of the residues ser87, asp263 and his285. these residues are not exposed to the solvent, but a narrow channel c ...19968683577
acute pleuropneumonia in barbary sheep (amnotragus lervia) associated with chromobacterium violaceum. 19968736506
isolation and identification of poly(3-hydroxyvalerate)-degrading strains of pseudomonas using selective enrichment of polyhydroxyalkanoate-degrading bacteria and poly(3-hydroxyvalerate)-containing granules from chromobacterium violaceum as the carbon source, 10 new pseudomonas lemoignei strains were isolated; these strains were able to degrade poly(3-hydroxyvalerate), as well as poly(3-hydroxybutyrate), in vitro. the new isolates were characterized and identified by comparing them with p. lemoignei lmg 2207(t) (t = type strain). like p. lemoignei lmg 2207(t) cells, the cells of ...19968782688
inhibition of microbial lipases with stereoisomeric triradylglycerol analog phosphonates.1,2(2,3)-diradylglycero o-(p-nitrophenyl) n-hexylphosphonates were synthesized, with the diradylglycerol moiety being di-o-octylglycerol, 1-o-hexadecyl-2-o-pyrenedecanylglycerol, or 1-o-octyl-2-oleoyl-glycerol, and tested for their ability to inactivate lipases from chromobacterium viscosum (cvl) and rhizopus oryzae (rol). the experimental data indicate the formation of stable, covalent 1:1 enzyme-inhibitor adducts with the di-o-alkylglycero phosphonates. the differences in reactivity of diaster ...19968982269
taxonomic study of bacteria isolated from plants: proposal of sphingomonas rosa sp. nov., sphingomonas pruni sp. nov., sphingomonas asaccharolytica sp. nov., and sphingomonas mali sp. nov.the taxonomic positions of 10 strains of 3-ketolactose-forming bacteria which were isolated from the roots of plants (rosa sp., psychotria nairobiensis, ardisia crispa, prunus persica, and apple trees) were investigated. the dna base compositions of these strains ranged from 64.0 to 65.7 mol%, the isoprenoid quinone of each strain was ubiquinone 10, 3-hydroxy fatty acids were lacking in the cellular fatty acids of these organisms, and all of the strains contained a sphingolipid with the long-cha ...19957537068
macrocyclic lactone synthesis by lipases in water-in-oil microemulsions.five microbial lipases from chromobacterium viscosum, candida cylindracea, pseudomonas (source fluka), pseudomonas (source genzyme) and lipoprotein lipase ex microbial (genzyme) have been screened for lactonisation activity towards 16-hydroxyhexadecanoic acid (hha) in a variety of different w/o microemulsion systems. with the exception of candida cylindracea (cc), all the lipases exhibited lactonisation activity although they were inherently more active in microemulsion systems based on the anio ...19957544159
phylogenetic inferences and taxonomic consequences of 16s ribosomal dna sequence comparison of chromohalobacter marismortui, volcaniella eurihalina, and deleya salina and reclassification of v. eurihalina as halomonas eurihalina comb. nov.the phylogenetic positions of the moderately halophilic bacteria chromohalobacter marismortui, volcaniella eurihalina, and deleya salina were determined by pcr amplification of rrna genes and direct sequencing. the resulting data were compared with data for other bacteria obtained from 16s rrna sequence databases. c. marismortui, v. eurihalina, and d. salina clustered phylogenetically within the gamma subclass of the proteobacteria and are closely related to other species on the halomonas-deleya ...19957547290
l-tryptophan 2',3'-oxidase from chromobacterium violaceum. substrate specificity and mechanistic implications.l-tryptophan 2',3'-oxidase, an amino acid alpha,beta-dehydrogenase isolated from chromobacterium violaceum, catalyzes the formation of a double bond between the c alpha and c beta carbons of various tryptophan derivatives provided that they possess: (i) a l-enantiomeric configuration, (ii) an alpha-carbonyl group, and (iii) an unsubstituted and unmodified indole nucleus. kinetic parameters were evaluated for a series of tryptophan analogues, providing information on the contribution of each chem ...19957559518
inversion of lipase stereospecificity for fluorogenic alkyldiacyl glycerols. effect of substrate solubilization.we synthesized enantiomeric 1-o-alkyl-2,3-diacyl-sn-glycerol and 3-o-alkyl-1,2-diacyl-sn-glycerol containing pyrene as a fluorescent reporter and the trinitrophenylamino residue as a fluorescence quencher; both reporter groups were covalently bound to the omega end of the acyl chains at positions sn-2 and sn-3(1), respectively. the fluorescence of the intact substrate molecules was very low. chemical or enzymic release of the fatty acyl chains lead to fluorescence dequenching. the rate of lipoly ...19957628484
preparative-scale kinetic resolutions catalysed by microbial lipases immobilised in aot-stabilised microemulsion-based organogels: cryoenzymology as a tool for improving enantioselectivity.gelatin-containing microemulsion based organogels have been used as an immobilisation matrix for lipases from a number of different sources. kinetic resolutions of octan-3-ol, 1-octen-3-ol and 1-octyn-3-ol by esterification with decanoic acid have been performed using chromobacterium viscosum (cv) lipase. cv lipase is highly enantioselective in favour of the (r)-(-) isomer of octan-3-ol, but the enantioselectivity is both reversed and decreased by the introduction of unsaturation at the 1-positi ...19957492618
third generation cephalosporin-resistant gram-negative bacilli in the feces of hospitalized view of the widespread use of third generation cephalosporins in hospitalized infants, we attempted to determine whether their use was associated with the emergence of resistance in fecal gram-negative bacilli. stools from infants hospitalized for varying durations were cultured on macconkey agar containing 4 micrograms/ml of cefotaxime. all isolates growing on this medium were identified and their susceptibilities to 29 antimicrobial agents were determined. sixty-five infants were studied of ...19957746715
mechanism of metal-independent hydroxylation by chromobacterium violaceum phenylalanine hydroxylase.phenylalanine hydroxylase converts phenylalanine to tyrosine utilizing a tetrahydrobiopterin cofactor. several key mechanistic questions have yet to be resolved, specifically the identity of the hydroxylating species and the role of the non-heme iron which is present in all of the mammalian pahs. recently, we have demonstrated that a bacterial pah from chromobacterium violaceum does not require any redox active metal for activity [carr, r. t., & benkovic, s. j. (1993) biochemistry 32, 14132-1413 ...19957779797
lipase from chromobacterium viscosum: biochemical characterization indicating homology to the lipase from pseudomonas glumae.previous purification of a commercial lipolytic preparation from chromobacterium viscosum using gel filtration chromatography yielded two enzymatically active fractions, named lipases a and b. characterization of these fractions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that lipase a consisted of a high molecular weight aggregate of lipase protein with lipopolysaccharides. this complex could be dissociated by treatment with edta-tris buffer containing the non-ionic de ...19957786905
stereoselectivity of microbial lipases. the substitution at position sn-2 of triacylglycerol analogs influences the stereoselectivity of different microbial the present study, the stereoselectivity of purified lipases from candida rugosa, chromobacterium viscosum, pseudomonas species and rhizopus arrhizus towards triacylglycerols in comparison to various structural analogs were investigated. different triacylglycerol analogs with distinct polarities at position sn-2 of the glycerol backbone (1,3-diacyl-2-x-glycerol, where 2-x = 2-acyloxy, 2-alkyloxy, 2-deoxy-2-alkyl, or 2-deoxy-2-phenyl) were synthesized. substrate hydrophobicity and steric requi ...19957851405
a study of reversibly inactivated lipases for use in a morphine-triggered naltrexone delivery system.a key component of an implant that can be triggered by external morphine to release naltrexone is an inactivated enzyme that can be activated by morphine and which can then rapidly remove a protective coating surrounding a bioerodible polymer containing dispersed naltrexone. in this article we describe a lipase that has been conjugated with o3-carboxymethylmorphine, morphine-beta-3-glucuronide and o3-carboxypropylmorphine. the enzyme conjugate was then inactivated by complexation with affinity-p ...19958582907
esterification reactions catalyzed by chromobacterium viscosum lipase in ctab-based microemulsion systems.chromobacterium viscosum (cv) lipase solubilized in water-in-oil (w/o) microemulsions based on the cationic surfactant hexadecyltrimethylammonium bromide (ctab) have been used for multigram-scale ester synthesis, including the kinetic resolution of a secondary alcohol. the stability of cv lipase in all the ctab microemulsions studied was excellent and was superior to that observed in aqueous buffer at the same ph and temperature. kinetic studies were performed using the synthesis of ethylhexadec ...199518623188
effects of sorbitol addition on the action of free and immobilized hydrolytic enzymes in organic media.the effect of the addition of sorbitol on the activity and stability of enzymes was examined by monitoring transesterification reactions performed in organic media at various water activities (a(w) = 0.08 to 0.97). lipases from chromobacterium viscosum and candida rugosa immobilized on celite, and chymotrypsin, free or immobilized on celite, were used. when the sorbitol-containing enzymes were employed, higher reaction rates and less hydrolysis were observed. immobilization of chymotrypsin resul ...199518623233
crystallization and preliminary x-ray analysis of a lipase from chromobacterium viscosum.lipase from chromobacterium viscosum has been purified to homogeneity and crystallized in a form suitable for x-ray diffraction analysis from 10-14% polyethylene glycol 4000 and 10-14% 2-methyl-2,4-pentane diol at ph 6.4 in the presence of 0.25%(w/v) n-octyl-beta-d-glucopyranoside. these crystals belong to space group p2(1)2(1)2 with refined lattice constants a = 41.1 a, b= 156.8, c = 43.6 a, indicating a cell content of one monomer per asymmetric unit of the crystal. the crystals diffract to a ...199415299463
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