Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| effect of counterions on the activity of lipase in cationic water-in-oil microemulsions. | this paper delineates how the different counterions affect the physicochemical properties of the aqueous aggregates and thereby the lipase activities at the interface of cationic water-in-oil microemulsions. to this end, we have synthesized a series of cetyltrimethylammonium-based surfactants, 1-14, having aliphatic, aliphatic with aromatic substitution at the alpha position, and aromatic carboxylate anion as the counterion. the physicochemical characterizations of these aqueous aggregates were ... | 2006 | 17014111 |
| antioxidant properties of violacein: possible relation on its biological function. | violacein, a violet pigment produced by chromobacterium violaceum, has attracted much attention in recent literature due to its pharmacological properties. in this work, the antioxidant properties of violacein were investigated. the reactivity with oxygen and nitrogen reactive species and 1,1-diphenyl-2-picryl-hydrazyl (dpph), a stable free radical, was evaluated. epr studies were carried out to evaluate the reactivity with the hydroxyl radical. the action of violacein against lipid peroxidation ... | 2006 | 17011197 |
| structures of human n-acetylglucosamine kinase in two complexes with n-acetylglucosamine and with adp/glucose: insights into substrate specificity and regulation. | n-acetylglucosamine (glcnac), a major component of complex carbohydrates, is synthesized de novo or salvaged from lysosomally degraded glycoconjugates and from nutritional sources. the salvage pathway requires that glcnac kinase converts glcnac to glcnac-6-phosphate, a component utilized in udp-glcnac biosynthesis or energy metabolism. glcnac kinase belongs to the sugar kinase/hsp70/actin superfamily that catalyze phosphoryl transfer from atp to their respective substrates, and in most cases cat ... | 2006 | 17010375 |
| chromobacterium violaceum: a case report of an unusual bacterium causing puerperal sepsis. | human infections by chromobacterium violaceum are rare. till date 6 cases have been reported from southern and eastern parts of india. we report here a case of puerperal sepsis by c. violaceum, probably the first case from eastern part of orissa. the patient was successfully treated with amikacin and gatifloxacin. | 2006 | 17001920 |
| mouse and human cell activation by n-dodecanoyl-dl-homoserine lactone, a chromobacterium violaceum autoinducer. | chromobacterium violaceum produces autoinducers, including homoserine lactones (hsls), for genetic regulation. among the seven hsls derived from c. violaceum we evaluated, only c(12)-hsl stimulated the production of inflammatory cytokines in mammalian monocytic cell lines through the activation of the nf-kappab signaling pathway besides their quorum-sensing role, like 3-oxo-c(12)-hsl from pseudomonas aeruginosa. | 2006 | 16982829 |
| [soft tissue infection in a diabetic patient from a subtropical region]. | 2006 | 16956538 | |
| cytotoxic activity of violacein in human colon cancer cells. | several studies have shown that violacein, a purple pigment extracted from chromobacterium violaceum, is capable to induce apoptosis in a variety of cancer cells, including those leukemia cell lines. herein, we examined the effects of violacein on reactive oxygen species (ros) production during the apoptotic colon cancer cell death. we demonstrate that violacein mediates ros production followed by activation of caspase-3, release of cytochrome c, and calcium release to citosol in caco-2 cells. m ... | 2006 | 16889929 |
| reevaluation of the violacein biosynthetic pathway and its relationship to indolocarbazole biosynthesis. | the biosynthetic pathways for violacein and for indolocarbazoles (rebeccamycin, staurosporine) include a decarboxylative fusion of two tryptophan units. however, in the case of violacein, one of the tryptophans experiences an unusual 1-->2 shift of the indole ring. the violacein biosynthetic gene cluster was previously reported to consist of four genes, vioabcd. here we studied the violacein pathway through expression of vio genes in escherichia coli and streptomyces albus. a pair of genes (vioa ... | 2006 | 16874749 |
| [chromobacterium violaceum peritonitis: case report and literature review]. | we report a case of chromobacterium violaceum infection and we review the literature for all published cases. c. violaceum grew from a peritoneal fluid of a 47-year-old woman operated on for peritonitis following perforative gastroduodenal ulcer. she was just coming back from a 1-month-holyday in french guyana, where she might have been in contact with this micro-organism. the patient fully recovered after surgical management associated with antibiotic therapy consisting of ofloxacin plus pipera ... | 2006 | 16829475 |
| physicochemical studies on cetylammonium bromide and its modified (mono-, di-, and trihydroxyethylated) head group analogues. their micellization characteristics in water and thermodynamic and structural aspects of water-in-oil microemulsions formed with them along with n-hexanol and isooctane. | the micellization behavior of cetylammonium bromide and its mono-, di-, and trihydroxyethylated head group analogues and water/oil (w/o) microemulsion formation with them have been studied with detailed thermodynamic and structural considerations. the critical micellar concentration, micellar aggregation number, and behavior of the surfactants at the air/solution interface have been studied in detail. the results have been analyzed and discussed. the formation of the w/o microemulsion stabilized ... | 2006 | 16771402 |
| unusual entropy-driven affinity of chromobacterium violaceum lectin cv-iil toward fucose and mannose. | the purple pigmented bacterium chromobacterium violaceum is a dominant component of tropical soil microbiota that can cause rare but fatal septicaemia in humans. its sequenced genome provides insight into the abundant potential of this organism for biotechnological and pharmaceutical applications and allowed an orf encoding a protein that is 60% identical to the fucose binding lectin (pa-iil) from pseudomonas aeruginosa and the mannose binding lectin (rs-iil) from ralstonia solanacearum to be id ... | 2006 | 16768446 |
| fatal septicaemia from chromobacterium violaceum: case reports and review of the literature. | chromobacterium violaceum rarely causes infection in humans and its mechanism of pathogenicity is not well understood. human infection carries a high mortality rate with a fulminating clinical progression. a high index of suspicion is required for diagnosis, and is based on recovering the organisms from blood cultures or other appropriate specimens. we present three cases of human infection managed in a tertiary referral hospital in hong kong with a review of the literature. | 2006 | 16760554 |
| on the pigment produced by chromobacterium violaceum. | 1927 | 16743932 | |
| inhibition of bacterial quorum sensing by vanilla extract. | the purpose of this study was to search for a novel quorum sensing inhibitor and analyse its inhibitory activity. | 2006 | 16706905 |
| chromobacterium violaceum infection. | 2006 | 16681318 | |
| epr and uv-vis studies of the nitric oxide adducts of bacterial phenylalanine hydroxylase: effects of cofactor and substrate on the iron environment. | phenylalanine hydroxylase from chromobacterium violaceum (cpah), which catalyzes phenylalanine oxidation to tyrosine, is homologous to the catalytic domain of eukaryotic pahs. previous crystallographic and spectroscopic studies on mammalian pah conflict on whether o2 binds to the open-coordination site or displaces the remaining water ligand to yield either a six- or a five-coordinate iron, respectively. the abilities of nitric oxide to behave as an oxygen mimic and a spectroscopic probe of ferr ... | 2006 | 16676991 |
| ecthyma gangrenosum and septic shock syndrome secondary to chromobacterium violaceum. | chromobacterium violaceum is a gram-negative bacterium of soil and water in tropical and subtropical environments. typically, it is considered a bacterium of low virulence although, uncommonly, it causes human infection, particularly in persons with defects in host defenses. infection generally follows exposure of broken skin to contaminated water and soil, and is often characterized by pustules, lymphadenitis, fever, and vomiting, as well as rapid dissemination and a high mortality rate. unfort ... | 2006 | 16631946 |
| alginate-chaperoned facile refolding of chromobacterium viscosum lipase. | urea denatured lipase from chromobacterium viscosum lipase could be refolded by addition of alginate with high guluronic acid content. the refolded molecule could be recovered by affinity precipitation. this approach resulted in recovery of 80% (of original activity) as compared to classical dilution method which gave only 21% activity recovery. dynamic light scattering showed that binding required about 45 min and activity data obtained from affinity precipitation experiments indicated that ref ... | 2006 | 16624637 |
| aquitalea magnusonii gen. nov., sp. nov., a novel gram-negative bacterium isolated from a humic lake. | a gram-negative, rod-shaped, non-spore-forming betaproteobacterium (tro-001dr8t) was isolated from humic-lake samples collected from northern wisconsin, usa. on the basis of 16s rrna gene sequence analysis, strain tro-001dr8t belonged to the family neisseriaceae, and the phylogenetic distance from its closest relative, chromobacterium violaceum, was 95 %. strain tro-001dr8t lacked the violet pigmentation of c. violaceum and shared only 26 % dna-dna relatedness with c. violaceum. the dna g+c cont ... | 2006 | 16585708 |
| important unusual infections in australia: a critical care perspective. | to review a number of the important unusual infections in australia that can lead to critical illness. | 2001 | 16573516 |
| effects of cyanide and dissolved oxygen concentration on biological au recovery. | the number of discarded electric devices containing traces of au is currently increasing. it is desirable to recover this au because of its valuable physicochemical properties. au is usually dissolved with relatively high concentrations of cyanide, which is associated with environmental risk. chromobacterium violaceum is able to produce and detoxify small amounts of cyanide, and may thus be able to recover au from discarded electric devices. this study investigated the effects of cyanide and dis ... | 2006 | 16567012 |
| chromobacterium violaceum, var. manilae as a pathogenic microörganism. | 1942 | 16560589 | |
| chromobacterium violaceum infection in two dogs. | chromobacterium violaceum is a saprophyte of soil and water in tropical and subtropical environments that is associated with rare but highly fatal infections in animals and humans. systemic infection was diagnosed in two critically ill dogs from florida. fever was absent in both dogs. both dogs were treated surgically and provided with intensive care, but only one survived. the identification of characteristic, violet-pigmented bacterial colonies on routine microbial cultures should alert microb ... | 2006 | 16527917 |
| an investigation of chlorophenol proton affinities and their influence on the biological activity of microorganisms. | the proton affinities of 15 chlorophenols are calculated by ab initio methods. straight correlation between proton affinities and changes in the electronic structure is observed. the proton affinities decrease linearly with the electronic density gain on the chlorine atoms, as the liberation of the proton increases. to confirm the importance of the proton affinities on the toxicity of chlorophenols, calorimetric responses of these molecules and related ones where the acid proton is changed to a ... | 2006 | 16451037 |
| production and properties of the native chromobacterium violaceum fucose-binding lectin (cv-iil) compared to homologous lectins of pseudomonas aeruginosa (pa-iil) and ralstonia solanacearum (rs-iil). | chromobacterium violaceum is a versatile, violet pigment (violacein)-producing beta-proteobacterium, confined to tropical and subtropical regions, dwelling in soil and water, like pseudomonas aeruginosa and ralstonia solanacearum. these three bacteria are saprophytes that occasionally become aggressive opportunistic pathogens virulently attacking animals (the first two) and plants (the third). the recent availability of their genome sequences enabled identification in the c. violaceum genome of ... | 2006 | 16436433 |
| the use of violacein to study biochemical behaviour of saccharomyces cerevisiae cells. | violacein, a biochemical compound produced by chromobacterium violaceum which has antichagasic properties, was used to study biochemical behaviour of saccharomyces cerevisiae cells. at 20 microm and 40 microm, violacein did not alter the membrane potential (deltapsi) of s. cerevisae cells, which means that the integrity of the cell membrane was maintained. on the other hand, at 60 microm and 80 microm, violacein produced significant alterations in the membrane potential. this information will be ... | 2005 | 16435565 |
| detection of chromobacterium violaceum by multiplex pcr targeting the prgi, spao, invg, and sipb genes. | based on the recently completed genomic sequence of chromobacterium violaceum american type culture collection (atcc) 12472 a multiplex pcr assay targeting the prgi, spao, invg, and sipb genes of the salmonella spi-1 homologue type-iii secretion system was developed. pcr products of 255bp (prgi), 749bp (spao), 1685bp (invg), and 1752bp (sipb) were successfully amplified simultaneously in a single reaction with all chr. violaceum strains investigated whereas other bacteria tested negative. the de ... | 2006 | 16423655 |
| [chromobacteriosis in ilhéus, bahia: epidemiologic, clinical and laboratorial investigation]. | in april/2004, a group of people traveled to a farm in a town in the south of bahia and afterwards, three teenagers from the same family developed symptoms of severe septicemia and two died. the health department carried out an epidemiologic, clinical, laboratory and environmental investigation that resulted in the identification of chromobacterium violaceum, in biological material from one of them, water and soil. this is the first report of the disease in bahia state. | 2006 | 16410927 |
| anti-quorum sensing activity of medicinal plants in southern florida. | bacterial intercellular communication, or quorum sensing (qs), controls the pathogenesis of many medically important organisms. anti-qs compounds are known to exist in marine algae and have the ability to attenuate bacterial pathogenicity. we hypothesized that terrestrial plants traditionally used as medicines may also produce anti-qs compounds. to test this hypothesis, 50 medicinal plants from southern florida were screened for anti-qs activity using two biomonitor strains, chromobacterium viol ... | 2006 | 16406418 |
| anaerobic nitrate-dependent iron(ii) bio-oxidation by a novel lithoautotrophic betaproteobacterium, strain 2002. | microbial nitrate-dependent fe(ii) oxidation is known to contribute to iron biogeochemical cycling; however, the microorganisms responsible are virtually unknown. in an effort to elucidate this microbial metabolic process in the context of an environmental system, a 14-cm sediment core was collected from a freshwater lake and geochemically characterized concurrently with the enumeration of the nitrate-dependent fe(ii)-oxidizing microbial community and subsequent isolation of a nitrate-dependent ... | 2006 | 16391108 |
| in vitro testing for genotoxicity of violacein assessed by comet and micronucleus assays. | chromobacterium violaceum is a gram (-) bacteria found in water samples and soils from tropical and subtropical regions of the world. violacein, the major pigment produced by these bacteria, has been shown to have antibiotic, antitumoral and trypanocidal activities. in the present work, the genotoxicity of violacein was investigated in four different cell lines by using the alkaline comet assay and in vero cells using the micronucleus test. in the alkaline comet assay, violacein, when tested at ... | 2006 | 16359912 |
| microbial degradation of asphalt. | organisms of the genera pseudomonas, chromobacterium, and bacillus capable of degrading asphalt were isolated by enrichment cultures. the asphalt degradation by these organisms varied from 3 to 25% after incubation for 1 week. the effects of temperature, ph, and atmosphere of incubation on asphalt degradation were investigated and were shown to vary with different organisms on the same substrate. | 1963 | 16349633 |
| denitrification by chromobacterium violaceum. | one host (rana catesbiana)-associated and two free-living mesophilic strains of bacteria with violet pigmentation and biochemical characteristics of chromobacterium violaceum were isolated from freshwater habitats. cells of each freshly isolated strain and of strain atcc 12472 (the neotype strain) grew anaerobically with glucose as the sole carbon and energy source. the major fermentation products of cells grown in trypticase soy broth (bbl microbiology systems, cockeysville, md.) supplemented w ... | 1986 | 16347164 |
| variability of the influence of physicochemical factors affecting bacterial adhesion to polystyrene substrata. | the role of electrostatic and hydrophobic interactions and solid and liquid surface tensions in the adhesion of four bacterial species (pseudomonas fluorescens, enterobacter cloacae, chromobacterium sp., and flexibacter sp.) to hydrophobic polystyrene petri dishes and to more hydrophilic polystyrene tissue culture dishes was investigated. the effect of electrostatic interactions was investigated by determining the effects of different electrolyte solutions on attachment to and of different elect ... | 1986 | 16347145 |
| diversity dynamics of marine bacteria studied by immunofluorescent staining on membrane filters. | of 34 strains of marine bacteria isolated on a general seawater medium, 5 were selected for detailed studies of their population dynamics in the plankton. the isolates were characterized as aeromonas sp., chromobacterium cf. lividum, vibrio sp., and two pseudomonas spp. specific antibodies were produced by immunization of rabbits, and bacterial cells were stained on black uni-pore membrane filters by an indirect immunofluorescent staining procedure. the method proved to be very specific and prac ... | 1982 | 16345920 |
| violacein synergistically increases 5-fluorouracil cytotoxicity, induces apoptosis and inhibits akt-mediated signal transduction in human colorectal cancer cells. | despite recent additions to the armory of chemotherapeutic agents for colorectal cancer (crc) treatment, the results of chemotherapy remain unsatisfactory. 5-fluorouracil (5-fu) still represents the cornerstone of treatment and resistance to its actions is a major obstacle to successful chemotherapy. therefore, new active agents in crc and agents that increase the chemosensitivity of cancer cells to 5-fu are still urgently required. violacein, a pigment isolated from chromobacterium violaceum in ... | 2006 | 16344270 |
| geometric constraints at the surfactant headgroup: effect on lipase activity in cationic reverse micelles. | the primary objective of the present article is to understand how the geometric constraints at the surfactant head affect the lipase activity in the reverse micellar interface. to resolve this issue, surfactants were designed and synthesized, and activity was measured in /water/isooctane/n-hexanol reverse micellar systems at z ([alcohol]/[surfactant])=5.6, ph 6.0 (20 mm phosphate), 25 degrees c across a varying range of w0 ([water]/[surfactant]) using p-nitrophenylalkanoates as the substrate. it ... | 2005 | 16342982 |
| production of acylated homoserine lactones by aeromonas and pseudomonas strains isolated from municipal activated sludge. | up to now, the production and role of n-acyl homoserine lactones (ahls) in activated sludge have been poorly understood. in this study, cross-feeding assays with the reporter strains agrobacterium tumefaciens ntl4 and chromobacterium violaceum cv026 were used to investigate ahl signal production by municipal activated sludge samples. ahl signal production was consistently detected from municipal activated sludge when different samples were incubated on nutrient media. from one municipal activate ... | 2005 | 16333331 |
| cell-cell influences on bacterial community development in aquatic biofilms. | dialysis tubing containing spent culture media, when placed in a lake, was colonized by a low diversity of bacteria, whereas abiotic controls had considerable diversity. changes were seen in the presence and absence of acylated homoserine lactones, suggesting that these molecules and other factors may influence adherent-population composition. | 2005 | 16332906 |
| 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 ... | 2004 | 16329888 |
| l-canavanine made by medicago sativa interferes with quorum sensing in sinorhizobium meliloti. | sinorhizobium meliloti is a gram-negative soil bacterium, capable of establishing a nitrogen-fixing symbiosis with its legume host, alfalfa (medicago sativa). quorum sensing plays a crucial role in this symbiosis, where it influences the nodulation process and the synthesis of the symbiotically important exopolysaccharide ii (eps ii). s. meliloti has three quorum-sensing systems (sin, tra, and mel) that use n-acyl homoserine lactones as their quorum-sensing signal molecule. increasing evidence i ... | 2005 | 16321947 |
| a case of chromobacterium infection after car accident in korea. | chromobacterium violaceum is a gram negative straight rod, 0.8-1.2 by 2.5 to 6.0 m, which is motile by one polar flagella and one to four lateral flagella. the organism inhabits soil and water and is often found in semitropical and tropical climates. infections in humans are rare. we report a case of infection caused by strains of c. violaceum. a 38-year-old male patient was admitted to kyunghee university hospital, seoul, korea on july 28th, 2003, after a car accident. the patient had multiple ... | 2005 | 16259070 |
| n-butanoyl-l-homoserine lactone (bhl) deficient pseudomonas aeruginosa isolates from an intensive care unit. | acylated homoserine lactones (ahls) are self-generated diffusible signal molecules that mediate population density dependent gene expression (quorum sensing) in a variety of gram-negative bacteria, and several virulence genes of human pathogens are known to be controlled by ahls. in this study, strains of pseudomonas aeruginosa, acinetobacter baumannii, escherichia coli and klebsiella pneumoniae, isolated from intensive care patients, were screened for ahl production by using ahl responsive indi ... | 2005 | 16255145 |
| 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 ... | 2001 | 16233091 |
| chromobacterium violaceum in siblings, brazil. | chromobacterium violaceum, a saprophyte bacterium found commonly in soil and water in tropical and subtropical climates, is a rare cause of severe, often fatal, human disease. we report 1 confirmed and 2 suspected cases of c. violaceum septicemia, with 2 fatalities, in siblings after recreational exposure in northeastern brazil. | 2005 | 16229777 |
| contrasting occurrence of chromobacterium violaceum in tropical drinking water springs of uganda. | occurrence of chromobacterium violaceum in six protected drinking water springs in uganda was investigated. c. violaceum showed a contrasting occurrence, which was independent of human impact as assessed by faecal pollution indicators. it was isolated from two springs (s1 and s2) that were located close to each other (3 km) but not in the rest. in s1 c. violaceum was continuously detected, in concentrations ranging from 6 to 270 cfu 100 ml(-1), while in s2 it was detected on only one sampling oc ... | 2005 | 16209027 |
| stable transformation of chromobacterium violaceum with a broad-host-range plasmid. | stable transformants of chromobacterium violaceum were obtained by high-voltage electroporation with a 7-kilobase binary plasmid. the technique was reliable, reproducible, and simple, with efficiencies of 10(5) transformants/microg of plasmid dna. the electrical conditions that resulted in the highest efficiencies were short pulse length (4.4-4.5 ms) and high voltage (12.5 kv/cm). the numbers of transformants were almost the same during the growth exponential phase (variation at optical density) ... | 2006 | 16172890 |
| surfactant tail length-dependent lipase activity profile in cationic water-in-oil microemulsions. | the catalytic activity of chromobacterium viscosum lipase (cv-lipase) was estimated across varying surfactant tail lengths (c-10-c-18) in water-in-oil (w/o) microemulsions of cationic surfactants containing four different hydroxyethyl-substituted head groups. an attempt to find a correlation, if any, between the activity of interfacially solubilized lipase and the varying surfactant tails was made for the first time in micellar enzymology. the second-order rate constant, k2, in lipase-catalyzed ... | 2005 | 16112238 |
| quorum sensing signal molecules (acylated homoserine lactones) in gram-negative fish pathogenic bacteria. | the aim of the present study was to investigate the production of quorum sensing signals (specifically acylated homoserine lactones, ahls) among a selection of strains of gram-negative fish bacterial pathogens. these signals are involved in the regulation of virulence factors in some human and plant-pathogenic bacteria. a total of 59 strains, representing 9 different fish pathogenic species, were tested against 2 ahl monitor bacteria (agrobacterium tumefaciens nt1 [pzlr4] and chromobacterium vio ... | 2005 | 16042042 |
| self-assembly of precursors in single-crystal growth of biopolymers. | self-assembly of precursors in dilute solution single-crystal growth of poly[(r)-3-hydroxyvalerate] (phv) and the fungal polysaccharide mycodextran were studied by transmission electron microscopy, especially at the early stages of crystallization. precursors for phv, such as small primary nuclei and tiny square tiles, consolidate to a large square crystal composed of orthogonally arranged tiles. by contrast, the precursors of mycodextran were lath-shaped, which suggests that the crystal growth ... | 2005 | 16004471 |
| head-group size or hydrophilicity of surfactants: the major regulator of lipase activity in cationic water-in-oil microemulsions. | to determine the crucial role of surfactant head-group size in micellar enzymology, the activity of chromobacterium viscosum (cv) lipase was estimated in cationic water-in-oil (w/o) microemulsions of three different series of surfactants with varied head-group size and hydrophilicity. the different series were prepared by subsequent replacement of three methyl groups of cetyltrimethylammonium bromide (ctab) with hydroxyethyl (1-3, series i), methoxyethyl (4-6, series ii), and n-propyl (7-9, seri ... | 2005 | 15977280 |
| genetic characterization of chromobacterium isolates from black water environments in the brazilian amazon. | to isolate and to characterize the diversity of chromobacterium violaceum from the brazilian amazon region. | 2005 | 15960747 |
| invasive chromobacterium violaceum infection in children: case report and review. | a 3.3-year-old boy developed chromobacterium violaceum abscesses of lungs, liver and spleen and was successfully treated. he had chronic granulomatous disease (cgd). twenty-five episodes of invasive c. violaceum infection in 24 children were reviewed. all 9 cgd and 10 nonbacteremic cases survived, but 12 of 16 (75%) non-cgd and 12 of 15 (80%) bacteremic patients died. | 2005 | 15933571 |
| quorum sensing in halophilic bacteria: detection of n-acyl-homoserine lactones in the exopolysaccharide-producing species of halomonas. | some members of the moderately halophilic genus halomonas, such as h. eurihalina, h. maura, h. ventosae and h. anticariensis, produce exopolysaccharides with applications in many industrial fields. we report here that these four species also produce autoinducer molecules that are involved in the cell-to-cell signaling process known as quorum sensing. by using the n-acyl homoserine lactone (ahl) indicator strains agrobacterium tumefaciens ntl4 (pzrl4) and chromobacterium violaceum cv026, we disco ... | 2005 | 15909077 |
| cloning and sequencing of a genomic island found in the brazilian purpuric fever clone of haemophilus influenzae biogroup aegyptius. | a genomic island was identified in the haemophilus influenzae biogroup aegyptius brazilian purpuric fever (bpf) strain f3031. this island, which was also found in other bpf isolates, could not be detected in non-bpf biogroup aegyptius strains or in nontypeable or typeable h. influenzae strains, with the exception of a region present in the type b eagan strain. this 34,378-bp island is inserted, in reference to h. influenzae rd kw20, within a choline transport gene and contains a mosaic structure ... | 2005 | 15784532 |
| 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 ... | 2004 | 15779589 |
| genotyping of chromobacterium violaceum isolates by reca pcr-rflp analysis. | intraspecies variation of chromobacterium violaceum was examined by comparative sequence - and by restriction fragment length polymorphism analysis of the recombinase a gene (reca-pcr-rflp). primers deduced from the known reca gene sequence of the type strain c. violaceum atcc 12472(t) allowed the specific amplification of a 1040bp reca fragment from each of the 13 c. violaceum strains investigated, whereas other closely related organisms tested negative. hindii-psti-reca rflp analysis generated ... | 2005 | 15766789 |
| enzyme hyperactivity in aot water-in-oil microemulsions is induced by 'lone' sodium counterions in the water-pool. | water-in-oil microemulsions are thermodynamically stable single-phase dispersions of water and surfactant within a continuous oil phase. the classical ternary system, based on the surfactant sodium bis(2-ethylhexyl)sulfosuccinate ('aot'), water and an alkane such as n-heptane, is an optically transparent monodispersion of spherical water-droplets coated with a close-packed surfactant monolayer and the droplet radius is, to a good first approximation, directly proportional to the molar water: sur ... | 2005 | 15715311 |
| effect of temperature, ph, and metals on the stability and activity of phenylalanine hydroxylase from chromobacterium violaceum. | phenylalanine hydroxylase (pah) is a non-heme iron dioxygenase catalyzing the conversion of phenylalanine to tyrosine and is present in both prokaryotic and eukaryotic organisms. a relatively simple pah is expressed by chromobacterium violaceum, a gram-negative bacterium found in tropical and subtropical regions. the effects of temperature, ph and metals on the stability and catalytic activity of chromobacterium violaceum pah were determined by steady-state kinetics, circular dichroism (cd) and ... | 2005 | 15708798 |
| the flag-2 locus, an ancestral gene cluster, is potentially associated with a novel flagellar system from escherichia coli. | escherichia coli k-12 possesses two adjacent, divergent, promoterless flagellar genes, fhia-mbha, that are absent from salmonella enterica. through bioinformatics analysis, we found that these genes are remnants of an ancestral 44-gene cluster and are capable of encoding a novel flagellar system, flag-2. in enteroaggregative e. coli strain 042, there is a frameshift in lfgc that is likely to have inactivated the system in this strain. tiling path pcr studies showed that the flag-2 cluster is pre ... | 2005 | 15687208 |
| chromobacterium violaceum septicaemia from north india. | though chromobacterium violaceum is a common inhabitant of soil and water in tropical and sub-tropical regions, human infections are rare but when they do occur result in high mortality. since the first case from malaysia in 1927, about 150 cases have been reported in world literature. till date 6 cases have been reported from southern and eastern parts of india. we report here a case of c. violaceum septicaemia, probably the first case from north india. the patient, a 6 and a half year old boy ... | 2004 | 15654137 |
| antibacterial constituents from the berries of piper nigrum. | piper nigrum finds an extensive application in antibacterial preparations belonging to ayurvedic system of medicine. a bioguided extraction and fractionation of the petroleum ether extract of the berries of p. nigrum afforded 2e, 4e, 8z-n-isobutyleicosatrienamide (1), pellitorine (2), trachyone (3), pergumidiene (4) and isopiperolein b (5). pergumidiene and trachyone are isolated for the first time from p. nigrum. all the isolated compounds were active against bacillus subtilis, bacillus sphaeri ... | 2004 | 15636188 |
| studies on the occurrence of gram-negative bacteria in ticks: ixodes ricinus as a potential vector of pasteurella. | a total of 372 ixodes ricinus ticks (101 females, 122 males, and 149 nymphs) collected by flagging in 6 mixed woodlands of eastern poland were examined by culture for the presence of internal gram-negative bacteria other than borrelia burgdorferi. adult ticks were examined in pools of 2 specimens each and nymphs were examined in pools of 3-5 specimens each. ticks were disinfected in 70 % ethanol and homogenized in 0.85% nacl. the diluted homogenate was inoculated onto 3 kinds of agar media: buff ... | 2004 | 15627343 |
| an analysis of type-iii secretion gene clusters in chromobacterium violaceum. | chromobacterium violaceum is an environmental gram-negative bacterium that is common in soil and water in tropical and sub-tropical regions. it is also a model organism for studying quorum-sensing and is a rare but deadly human pathogen. recent completion of the genome sequence of c. violaceum strain atcc 12472 revealed the presence of genes associated with type-iii secretion systems (ttsss). one of these systems resembles the spi-1 system found in salmonella enterica, whereas another is similar ... | 2004 | 15488386 |
| cytotoxic effects of violacein in human uveal melanoma cell lines. | violacein is the main pigment produced by chromobacterium violaceum, a saprophytic gram-negative bacillus. violacein is formed by the condensation of two modified tryptophan molecules and has potential anti-neoplastic effects. the purpose of this pilot study was to investigate the in vitro activity of violacein in human uveal melanoma cell lines. human uveal melanoma cell lines 92.1 and ocm-1 were incubated with five different concentrations of violacein (10(-5)-10(-9) m), and the total cellular ... | 2004 | 15457100 |
| pathologic quiz case: a 13-year-old boy with a 2-day history of fever, vomiting, and mental status changes. chromobacterium violaceum bacteremia. | 2004 | 15387687 | |
| metal solubilization from metal-containing solid materials by cyanogenic chromobacterium violaceum. | different cyanogenic bacterial strains (chromobacterium violaceum, pseudomonas fluorescens, bacillus megaterium) were cultivated under cyanide-forming conditions in the presence of metal-containing solids such as nickel powder or electronic scrap. all microorganisms were able to form water-soluble metal cyanides, however, with different efficiencies. c. violaceum was able to mobilize nickel as tetracyanonickelate [ni(cn)4(2-)] from fine-grained nickel powder. gold was microbially solubilized as ... | 2004 | 15380664 |
| conversion of (2s)-arginine to (2s,3r)-capreomycidine by vioc and viod from the viomycin biosynthetic pathway of streptomyces sp. strain atcc11861. | 2004 | 15368582 | |
| vioc is a non-heme iron, alpha-ketoglutarate-dependent oxygenase that catalyzes the formation of 3s-hydroxy-l-arginine during viomycin biosynthesis. | 2004 | 15368580 | |
| [violacein: a molecule of biological interest originating from the soil-borne bacterium chromobacterium violaceum]. | soil micro-organisms have evolved functions that allow them to withstand the strong competition for survival that characterizes most of their habitats. the production of antibiotic or antifungal compounds is one of these mechanisms. the relevant molecules often exhibit valuable therapeutic properties. | 2004 | 15363621 |
| a novel galphaq/11-selective inhibitor. | ym-254890, which was isolated from the culture broth of chromobacterium sp., inhibits adp-induced platelet aggregation and has antithrombotic and thrombolytic effects. ym-254890 blocks galpha(q/11)-coupled adp receptor p2y1-mediated ca(2+) mobilization. here we report that ym-254890 is a selective galpha(q/11) inhibitor. ym-254890 blocked ca(2+) mobilization mediated by several galpha(q/11)-coupled receptors but not by galpha(i)- or galpha(15)-coupled receptor, indicating that phospholipase cbet ... | 2004 | 15339913 |
| flow microcalorimetric studies of phenol and its chlorinated derivatives and a theoretical evaluation of their possible inhibition mode on chromobacterium violaceum respiration. | the general belief that chemical structure determines the biological effect of drugs has led to several techniques to establish structure-activity relationships (sar) that is useful in the development of more active compounds. predicting toxic effects based on sar, one can obtain toxicological data with a low cost-benefit ratio. chlorophenols that represent a class of toxic agents frequently used in industrial processes are not satisfactorily described in the literature in relation to their toxi ... | 2004 | 15336391 |
| 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 ... | 1994 | 15299463 |
| a simple screening protocol for the identification of quorum signal antagonists. | quorum sensing (qs) is a mechanism by which diverse microorganisms can control specific processes in response to population density. a relatively well-known form of qs among proteobacteria involves production and subsequent response to acylated homoserine lactones (ahls). quorum sensing inhibition (qsi), targeting ahl-dependent signaling, has been reported as a strategy for the control of biofilm formation used by several marine organisms. we developed a simple soft agar overlay protocol, based ... | 2004 | 15279939 |
| two new bacterial pathogens of colorado potato beetle coleoptera: chrysomelidae). | other than bacillus thuringiensis berliner, few bacteria are lethal to the colorado potato beetle (leptinotarsa decemlineata [say]), a major pest of potatoes and eggplant. expanded use of biologicals for the control of colorado potato beetle will improve resistance management, reduce pesticide use, and produce novel compounds for potential use in transgenic plants. using freeze-dried, rehydrated artificial diet in pellet form to screen bacteria lethal to other insects, we determined that strains ... | 2004 | 15279252 |
| effects of natural and chemically synthesized furanones on quorum sensing in chromobacterium violaceum. | cell to cell signaling systems in gram-negative bacteria rely on small diffusible molecules such as the n-acylhomoserine lactones (ahl). these compounds are involved in the production of antibiotics, exoenzymes, virulence factors and biofilm formation. they belong to the class of furanone derivatives which are frequently found in nature as pheromones, flavor compounds or secondary metabolites. to obtain more information on the relation between molecular structure and quorum sensing, we tested a ... | 2004 | 15233843 |
| use of sinorhizobium meliloti as an indicator for specific detection of long-chain n-acyl homoserine lactones. | population-density-dependent gene expression in gram-negative bacteria involves the production of signal molecules characterized as n-acyl homoserine lactones (ahls). the synthesis of ahls by numerous microorganisms has been identified by using biosensor strains based on the agrobacterium tumefaciens and chromobacterium violaceum quorum-sensing systems. the symbiotic nitrogen-fixing bacterium sinorhizobium meliloti is rapidly becoming a model organism for the study of quorum sensing. this organi ... | 2004 | 15184178 |
| burkholderia cenocepacia phage bcepmu and a family of mu-like phages encoding potential pathogenesis factors. | we have isolated bcepmu, a mu-like bacteriophage whose host range includes human pathogenic burkholderia cenocepacia (formally b. cepacia genomovar iii) isolates, and determined its complete 36748 bp genomic sequence. like enteric bacteriophage mu, the bcepmu genomic dna is flanked by variable host sequences, a result of transposon-mediated replication. the bcepmu genome encodes 53 proteins, including capsid assembly components related to those of mu, and tail sheath and tube proteins related to ... | 2004 | 15184022 |
| ym-254890 analogues, novel cyclic depsipeptides with galpha(q/11) inhibitory activity from chromobacterium sp. qs3666. | the structure elucidation and biological activity of novel ym-254890 (1) analogues and semi-synthetic derivatives are described. three natural analogues, ym-254891 (2), ym-254892 (3), and ym-280193 (4), were isolated from the fermentation broth of chromobacterium sp. qs3666, and two hydrogenated derivatives, ym-385780 (5) and ym-385781 (6), were synthesized from ym-254890. their structures were determined by one- and two-dimensional nmr studies and mass spectrometry. among these compounds, two n ... | 2004 | 15158780 |
| molecular mechanism of violacein-mediated human leukemia cell death. | violacein, a pigment isolated from chromobacterium violaceum in the amazon river, presents diverse biologic properties and attracts interest as a consequence of its antileukemic activity. elucidation of the molecular mechanism mediating this activity will provide further relevant information for understanding its effects on the cellular physiology of untransformed cells and for considering its possible clinical application. here, we show that violacein causes apoptosis in hl60 leukemic cells but ... | 2004 | 15130948 |
| identification of chromobacterium violaceum genes with potential biotechnological application in environmental detoxification. | chromobacterium violaceum is a gram-negative bacterium found in a wide variety of tropical and subtropical ecosystems. the complete genome sequence of c. violaceum atcc 12472 is now available, and it has considerable biotechnological potential for various applications, such as environmental detoxification, as well as medical and agricultural use. we examined the biotechnological potential of c. violaceum for environmental detoxification. three operons, comprising the ars operon, involved in arse ... | 2004 | 15100998 |
| dna repair in chromobacterium violaceum. | chromobacterium violaceum is a gram-negative beta-proteobacterium that inhabits a variety of ecosystems in tropical and subtropical regions, including the water and banks of the negro river in the brazilian amazon. this bacterium has been the subject of extensive study over the last three decades, due to its biotechnological properties, including the characteristic violacein pigment, which has antimicrobial and anti-tumoral activities. c. violaceum promotes the solubilization of gold in a mercur ... | 2004 | 15100997 |
| energetic metabolism of chromobacterium violaceum. | chromobacterium violaceum is a free-living microorganism, normally exposed to diverse environmental conditions; it has a versatile energy-generating metabolism. this bacterium is capable of exploiting a wide range of energy resources by using appropriate oxidases and reductases. this allows c. violaceum to live in both aerobic and anaerobic conditions. in aerobic conditions, c. violaceum is able to grow in a minimal medium with simple sugars, such as glucose, fructose, galactose, and ribose; bot ... | 2004 | 15100996 |
| chromobacterium violaceum genome: molecular mechanisms associated with pathogenicity. | chromobacterium violaceum is a versatile, gram-negative beta-protebacterium that grows in a variety of ecosystems in tropical and subtropical areas, such as the water and borders of the negro river, in the amazon region of brazil. although it is a saprophyte and is generally considered non-pathogenic, sporadic cases of human infection have been described, mainly in young children and in immunodeficient individuals. although rare, infections with c. violaceum are characterized by rapid disseminat ... | 2004 | 15100995 |
| drug resistance in chromobacterium violaceum. | chromobacterium violaceum is a free-living bacterium commonly found in aquatic habitats of tropical and subtropical regions of the world. this bacterium is able to produce a large variety of products of biotechnological and pharmacological use. although c. violaceum is considered to be non-pathogenic, some cases of severe infections in humans and other animals have been reported. genomic data on the type strain atcc 12472(t) has provided a comprehensive basis for detailed studies of pathogenicit ... | 2004 | 15100994 |
| transport genes of chromobacterium violaceum: an overview. | the complete genome sequence of the free-living bacterium chromobacterium violaceum has been determined by a consortium of laboratories in brazil. almost 500 open reading frames (orfs) coding for transport-related membrane proteins were identified in c. violaceum, which represents 11% of all genes found. the main class of transporter proteins is the primary active transporters (212 orfs), followed by electrochemical potential-driven transporters (154 orfs) and channels/pores (62 orfs). other cla ... | 2004 | 15100993 |
| tolerance to stress and environmental adaptability of chromobacterium violaceum. | chromobacterium violaceum is a gram-negative bacterium, abundant in a variety of ecosystems in tropical and subtropical regions, including the water and borders of the negro river, a major component of the amazon basin. as a free-living microorganism, c. violaceum is exposed to a series of variable conditions, such as different sources and abundance of nutrients, changes in temperature and ph, toxic compounds and uv rays. these variations, and the wide range of environments, require great adapta ... | 2004 | 15100992 |
| chemotaxis and flagellar genes of chromobacterium violaceum. | the availability of the complete genome of the gram-negative beta-proteobacterium chromobacterium violaceum has increasingly impacted our understanding of this microorganism. this review focuses on the genomic organization and structural analysis of the deduced proteins of the chemosensory adaptation system of c. violaceum. c. violaceum has multiple homologues of most chemotaxis genes, organized mostly in clusters in the bacterial genome. we found at least 67 genes, distributed in 10 gene cluste ... | 2004 | 15100991 |
| genetic analysis of violacein biosynthesis by chromobacterium violaceum. | chromobacterium violaceum presents a distinctive phenotypic characteristic, the production of a deep violet pigment named violacein. although the physiological function of this pigment is not well understood, the sequencing of the genome of this bacterium has given some insight into the mechanisms and control of violacein production. it was found that erythrose-4-phosphate (e4p), a precursor to aromatic amino acid biosynthesis, is produced by the non-oxidative portion of the hexose monophosphate ... | 2004 | 15100990 |
| 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 ... | 2004 | 15100989 |
| 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 ... | 2004 | 15100988 |
| closure of rrna related gaps in the chromobacterium violaceum genome with the pcr-assisted contig extension (pace) protocol. | in 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 ... | 2004 | 15100987 |
| 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 ... | 2004 | 15100986 |
| 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 ... | 2003 | 15058194 |
| 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 ... | 2004 | 15040257 |
| 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 ... | 2004 | 15006783 |
| 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 ... | 2004 | 14999516 |
| 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. | 2004 | 14974622 |
| chromobacterial infection in man. | 1952 | 14932538 | |
| a study of the wide spread distribution of chromobacterium species in soil by a simple technique. | 1951 | 14897823 |