TitleAbstractYear(sorted ascending)
the unique kinetic behavior of the very large nad-dependent glutamate dehydrogenase from janthinobacterium lividum.the kinetics of a very large nad-dependent glutamate dehydrogenase from janthinobacterium lividum showed positive cooperativity toward alpha-ketoglutarate and nadh, and the michaelis-menten type toward ammonium chloride in the absence of the catalytic activator, l-aspartate. an increase in the maximum activity accompanied the decrease in the s(0.5) values for alpha-ketoglutarate and nadh with the addition of l-aspartate, and the kinetic response for alpha-ketoglutarate changed completely to a ty ...201020378971
bacillus pumilus of palk bay origin inhibits quorum-sensing-mediated virulence factors in gram-negative bacteria.the aim of the current study was to inhibit quoring-sensing(qs)-mediated virulence factors of representative gram-negative bacteria by marine bacterial isolates. bacteria isolated from palk bay sediments were screened for anti-qs activity. eleven strains inhibited qs signals in chromobacterium violaceum (atcc 12472) and c. violaceum cv026. the marine bacterial strain s8-07 reduced the accumulation of n-acyl homoserine lactone (ahls) and showed significant inhibition of lasa protease(76%), lasb e ...201020381609
growth inhibition and pro-apoptotic activity of violacein in ehrlich ascites tumor.the continuing threat to biodiversity lends urgency to the need of identification of sustainable source of natural products. this is not so much trouble if there is a microbial source of the compound. herein, violacein, a natural indolic pigment extracted from chromobacterium violaceum, was evaluated for its antitumoral potential against the ehrlich ascites tumor (eat) in vivo and in vitro. evaluation of violacein cytotoxicity using different endpoints indicated that eat cells were twofold (ic(5 ...201020416285
water-in-ionic liquid microemulsion-based organogels as novel matrices for enzyme immobilization.the use of water-in-ionic liquid microemulsion-based organogels (w/il mbgs) as novel supports for the immobilization of lipase b from candida antarctica and lipase from chromobacterium viscosum was investigated. these novel lipase-containing w/il mbgs can be effectively used as solid phase biocatalysts in various polar and non-polar organic solvents or ils, exhibiting up to 4.4-fold higher esterification activity compared to water-in-oil microemulsion-based organogels. the immobilized lipases re ...201020449844
novel tryptophan metabolites, chromoazepinone a, b and c, produced by a blocked mutant of chromobacterium violaceum, the biosynthetic implications and the biological activity of chromoazepinone a and b.chromobacterium violaceum produces tryptophan metabolites, purple pigments of violacein and deoxyviolacein. a blocked mutant was prepared with n-methyl-n'-nitrosoguanidine to gain insights into the biosynthetic mechanisms of the pigments. five tryptophan metabolites were isolated: three novel compounds, named chromoazepinone a, b and c and two known compounds, chromopyrrolic acid and arcyriarubin a. the structure determinations of the three novel compounds are described. the biosynthetic pathway ...201020490411
chromobacterium pathogenicity island 1 type iii secretion system is a major virulence determinant for chromobacterium violaceum-induced cell death in hepatocytes.summary chromobacterium violaceum is a gram-negative bacterium that causes fatal septicaemia in humans and animals. c. violaceum atcc 12472 possesses genes associated with two distinct type iii secretion systems (t3sss). one of these systems is encoded by chromobacterium pathogenicity islands 1 and 1a (cpi-1/-1a), another is encoded by chromobacterium pathogenicity island 2 (cpi-2). here we show that c. violaceum causes fulminant hepatitis in a mouse infection model, and cpi-1/-1a-encoded t3ss i ...201020545857
antimycobacterial activity in vitro of pigments isolated from antarctic this study, we describe the antimycobacterial activity of two pigments, violacein, a purple violet pigment from janthinobacterium sp. ant5-2 (j-pvp), and flexirubin, a yellow-orange pigment from flavobacterium sp. ant342 (f-yop). these pigments were isolated from bacterial strains found in the land-locked freshwater lakes of schirmacher oasis, east antarctica. the minimum inhibitory concentrations (mics) of these pigments for avirulent and virulent mycobacteria were determined by the micropla ...201020556653
identification and characterization of a novel bacterial atp-sensitive k+ channel.five bacterial species that are most likely to have putative prokaryotic inward rectifier k(+) (kir) channels were selected by in silico sequence homology and membrane topology analyses with respect to the number of transmembrane domains (tms) and the presence of k(+) selectivity filter and/or atp binding sites in reference to rabbit heart inward rectifier k(+) channel (kir6.2). a dot blot assay with genomic dnas when probed with whole rabbit kir6.2 cdna further supported the in silico analysis ...201020571950
origin of the pka shift of the catalytic lysine in acetoacetate decarboxylase.the pka value of lys115, the catalytic residue in acetoacetate decarboxylate, was calculated using atomic coordinates of the x-ray crystal structure with consideration of the protonation states of all titratable sites in the protein. the calculated pka value of lys115 (pka(lys115)) was unusually low (approximately 6) in agreement with the experimentally measured value. although charged residues impact pka(lys115) considerably in the native protein, the significant pka(lys115) downshift in the pr ...201020621098
phenotypic and physiological alterations by heterologous acylhomoserine lactone synthase expression in pseudomonas putida.many bacteria harbour an incomplete quorum-sensing (qs) system, whereby they possess luxr homologues without the qs acylhomoserine lactone (ahl) synthase, which is encoded by a luxi homologue. an artificial ahl-producing plasmid was constructed using a cvii gene encoding the c6-ahl [n-hexanoyl homoserine lactone (hhl)] synthase from chromobacterium violaceum, and was introduced successfully into both the wild-type and a ppor (luxr homologue) mutant of pseudomonas putida. our data provide evidenc ...201020705668
evaluation of anti-quorum-sensing activity of edible plants and fruits through inhibition of the n-acyl-homoserine lactone system in chromobacterium violaceum and pseudomonas find out an alternative strategy to antibiotic usage against bacterial infection.201020720417
enterobacteriaceae associated with eggs of podocnemis expansa and podocnemis unifilis (testudines:chelonia) in nonpolluted sites of national park of araguaia plains, brazil.fertile eggs of podocnemis expansa and podocnemis unifilis were investigated for the presence of enterobacteria, as these two endangered species have the potential for conservation measures that include egg transfer. knowledge of normal microflora associated with turtles and turtle eggs would help effectively manage the transfer of these eggs among institutions. thirty eggs of each species were collected, aseptically transferred, cracked inside plastic bags containing tetrathionate broth, and sp ...201021370647
immunomodulatory, analgesic and antipyretic effects of violacein isolated from chromobacterium violaceum.violacein was isolated from chromobacterium violaceum, a soil gram negative bacterium collected from the forest water body soil sample of kolli hills; tamil nadu, india. in the present study the immunomodulatory, analgesic and antipyretic activities of violacein were investigated in wistar rats and mice. analgesic effect was evaluated by acetic acid- induced writhing, formalin induced paw licking and hotplate tests. immunomodulatory effect was investigated by using ovalbumin- induced active paw ...201019576742
characterization of the highly active polyhydroxyalkanoate synthase of chromobacterium sp. strain usm2.the synthesis of bacterial polyhydroxyalkanoates (pha) is very much dependent on the expression and activity of a key enzyme, pha synthase (phac). many efforts are being pursued to enhance the activity and broaden the substrate specificity of phac. here, we report the identification of a highly active wild-type phac belonging to the recently isolated chromobacterium sp. usm2 (phac(cs)). phac(cs) showed the ability to utilize 3-hydroxybutyrate (3hb), 3-hydroxyvalerate (3hv), and 3-hydroxyhexanoat ...201121398494
the chromobacterium violaceum type iii effector cope, a guanine nucleotide exchange factor for rac1 and cdc42, is involved in bacterial invasion of epithelial cells and pathogenesis.the type iii secretion system (t3ss) encoded by chromobacterium pathogenicity islands 1 and 1a (cpi-1/-1a) is critical for chromobacterium violaceum pathogenesis. t3ss-dependent virulence is commonly characterized by type iii effector virulence function, but the full repertoire of the effector proteins of cpi-1/-1a t3ss is unknown. in this study, we showed that expression of cpi-1/-1a t3ss is controlled by the master regulator cila. we used transcriptional profiling with dna microarrays to defin ...201121435035
screening of traditional chinese medicinal plants for quorum-sensing inhibitors activity.the misuse of antibiotics has contributed to widespread development of antimicrobial resistance among clinically significant bacterial species. alternative approaches other than those using antibiotics are needed in the fight against infectious diseases. quorum sensing (qs) is an intercellular signaling and gene regulatory mechanism, which is used by a number of opportunistic pathogenic bacteria in determining virulence gene expression. the study of qs may yield another strategy for disease cont ...201121439518
antipathogenic potential of marine bacillus sp. ss4 on n-acyl-homoserine-lactone-mediated virulence factors production in pseudomonas aeruginosa (pao1).antipathogenic therapy is an outcome of the quorum-sensing inhibition (qsi) mechanism, which targets autoinducer-dependent virulent gene expression in bacterial pathogens. n-acyl homoserine lactone (ahl) acts as a key regulator in the production of virulence factors and biofilm formation in pseudomonas aeruginosa pao1 and violacein pigment production in chromobacterium violaceum. in the present study, the marine bacterial strain ss4 showed potential qsi activity in a concentration-dependent mann ...201121451248
characterization of a chromobacterium haemolyticum population from a natural tropical study genetic diversity of chromobacterium haemolyticum isolates recovered from a natural tropical lake.201121466570
characterization of a gene cluster and its putative promoter region for violacein biosynthesis in pseudoalteromonas sp. 520p1.violacein, a purple pigment produced by some gram-negative bacteria, has various physiological properties, such as antitrypanosomal and antitumoral activities. a gene cluster that encodes five enzymes, vioa-vioe, is responsible for synthesizing violacein. the expression of these enzymes is known to be regulated by a quorum sensing mechanism in chromobacterium violaceum and pseudoalteromonas sp. 520p1. to clarify the molecular mechanism of regulation of violacein synthesis, we cloned and characte ...201121472536
phenolic composition and antimicrobial and antiquorum sensing activity of an ethanolic extract of peels from the apple cultivar annurca.abstract this study investigated the phenolic composition and antioxidant capacity of an ethanolic extract from the peel of the annurca (malus domestica var. annurca), which is widespread in the campania region of southern italy. the antimicrobial effect of the extract on different pathogens was also examined. the potential antiquorum sensing activity of the extract was tested by using the microorganism chromobacterium violaceum. ultra-performance liquid chromatography revealed that rutin, epica ...201121476926
enzymatic transesterification of jatropha curcas oil assisted by ultrasonication.ultrasonication used for the production of fatty acid methyl ester from non-edible vegetable oil using immobilized lipase (chromobacterium viscosum) as a catalyst from enterobacter aerogenes to make the process fully ecologically and environmental friendly. the optimal conditions for biodiesel production is the molar ratio oil to methanol 1:4, catalyst concentration 5 wt.% of oil, reaction time 30min, ultrasonic amplitude 50% (100w/m(3)) and cycle 0.7s. ultrasonication reduce the reaction time c ...201121489849
pyrosequencing demonstrated complex microbial communities in a membrane filtration system for a drinking water treatment plant.microbial community composition in a pilot-scale microfiltration plant for drinking water treatment was investigated using high-throughput pyrosequencing technology. sequences of 16s rrna gene fragments were recovered from raw water, membrane tank particulate matter, and membrane biofilm, and used for taxonomic assignments, estimations of diversity, and the identification of potential pathogens. greater bacterial diversity was observed in each sample (1,133-1,731 operational taxonomic units) tha ...201121502735
degradation of n-acylhomoserine lactone quorum sensing signaling molecules by potato root surface-associated chryseobacterium strains.n-acylhomoserine lactones (ahls) are used as quorum-sensing signaling molecules by many gram-negative bacteria. here, 413 bacterial strains were obtained from the roots of potato plants and screened for ahl-degrading bacteria using chromobacterium violaceum reporter strains. sixty one isolates degraded n-hexanoyl-l-homoserine lactone (c6-hsl) within 24 h. based on their 16s rrna gene sequences, most of these isolates were assigned to the genus chryseobacterium and divided into eight groups. most ...201121502740
a strategy for antagonizing quorum sensing.quorum-sensing bacteria communicate via small molecules called autoinducers to coordinate collective behaviors. because quorum sensing controls virulence factor expression in many clinically relevant pathogens, membrane-permeable quorum sensing antagonists that prevent population-wide expression of virulence genes offer a potential route to novel antibacterial therapeutics. here, we report a strategy for inhibiting quorum-sensing receptors of the widespread luxr family. structure-function studie ...201121504831
nonpigmented chromobacterium violaceum bacteremic cellulitis after fish bite.a case of nonpigmented chromobacterium violaceum bacteremic cellulitis after fish bite in taiwan is reported. the patient was successfully treated with ciprofloxacin and doxycycline for an extended period. chromobacterium violaceum should be listed in the differential diagnosis of patients with nonspecific cellulitis associated with marked leukocytosis and rapid progression to septicemia either with or without a distinct history of exposure to water or soil. a combination of prompt diagnosis, op ...201121524969
romidepsin (istodax, nsc 630176, fr901228, fk228, depsipeptide): a natural product recently approved for cutaneous t-cell lymphoma.romidepsin (istodax), a selective inhibitor of histone deacetylases (hdacs), was approved for the treatment of cutaneous t-cell lymphoma in november 2009 by the us food and drug administration. this unique natural product was discovered from cultures of chromobacterium violaceum, a gram-negative bacterium isolated from a japanese soil sample. this bicyclic compound acts as a prodrug, its disulfide bridge being reduced by glutathione on uptake into the cell, allowing the free thiol groups to inte ...201121587264
regulation of lectin production by the human pathogens pseudomonas aeruginosa and chromobacterium violaceum: effects of choline, trehalose, and ethanol. 201121618111
quorum sensing in chromobacterium violaceum: dna recognition and gene regulation by the cvir receptor.the bacterial pathogen chromobacterium violaceum uses a luxir-type quorum-sensing system to detect and respond to changes in cell population density. cvii synthesizes the autoinducer c10-homoserine lactone (c10-hsl) and cvir is a cytoplasmic dna binding transcription factor that activates gene expression following binding to c10-hsl. a number of behaviors are controlled by quorum sensing in c. violaceum. however, few genes have been shown to be directly controlled by cvir, in part because the dn ...201121622734
multiple loci are involved in quorum quenching of autoinducer i molecules in the nitrogen-fixing symbiont (sino-) rhizobium sp. ngr234.rhizobium sp. ngr234 is a unique α-proteobacterium (order - rhizobiales) that forms nitrogen-fixing nodules with more legumes than any other micro-symbiont. since we have previously described the complete genome sequence of ngr234, we now report on a genome wide functional analysis of the genes and enzymes involved in autoinducer i hydrolysis in this microbe. altogether we identified five cosmid clones that repeatedly gave a positive result in our function-based approach for the detection of aut ...201121642401
folding dynamics of phenylalanine hydroxylase depends on the enzyme's metallation state: the native metal, iron, protects against aggregate intermediates.phenylalanine hydroxylase (pah), a non-heme iron enzyme, is responsible for the phenylalanine conversion to tyrosine. its malfunction causes phenylketonuria (pku). to better understand how protein structure and folding profiles are affected by the metal cofactor, we investigated the chemical (un)folding of apo- and holo-pah from chromobacterium violaceum (cpah) using circular dichroism (cd) and analytical ultracentrifugation (auc). holo-cpah shows a two-state unfolding transition. in contrast, t ...201121647679
thailandepsins: bacterial products with potent histone deacetylase inhibitory activities and broad-spectrum antiproliferative activities.histone deacetylase (hdac) inhibitors have emerged as a new class of anticancer drugs, with one synthetic compound, saha (vorinostat, zolinza; 1), and one natural product, fk228 (depsipeptide, romidepsin, istodax; 2), approved by fda for clinical use. our studies of fk228 biosynthesis in chromobacterium violaceum no. 968 led to the identification of a cryptic biosynthetic gene cluster in the genome of burkholderia thailandensis e264. genome mining and genetic manipulation of this gene cluster fu ...201121793558
violacein and related tryptophan metabolites produced by chromobacterium violaceum: biosynthetic mechanism and pathway for construction of violacein core.violacein is a natural violet pigment produced by several gram-negative bacteria, including chromobacterium violaceum, janthinobacterium lividum, and pseudoalteromonas tunicata d2, among others. this pigment has potential medical applications as antibacterial, anti-trypanocidal, anti-ulcerogenic, and anticancer drugs. the structure of violacein consists of three units: a 5-hydroxyindole, an oxindole, and a 2-pyrrolidone. the biosynthetic origins of hydrogen, nitrogen, and carbon in the pyrrolido ...201121779844
inhibiting effect of bioactive metabolites produced by mushroom cultivation on bacterial quorum sensing-regulated behaviors.aims: this study aimed to search for novel quorum sensing (qs) inhibitors from mushroom and to analyze their inhibitory activity, with a view to their possible use in controlling detrimental infections. methods: the bioactive metabolites produced by mushroom cultivation were tested for their abilities to inhibit qs-regulated behavior. all mushroom strains were cultivated in potato-dextrose medium by large-scale submerged fermentation. the culture supernatant was condensed into 0.2 vol by freeze- ...201121778717
gold nanorod in reverse micelles: a fitting fusion to catapult lipase activity.lipase solubilized within gold nanorod doped ctab reverse micelles exhibited remarkable improvement in its activity mainly due to the enhanced interfacial domain of newly developed self-assembled nanocomposites.201121776523
an expedient biocatalytic procedure for abasic site precursors useful in oligonucleotide synthesis.preparation of abasic site precursors through a divergent chemoenzymatic synthesis has been accomplished. several biocatalysts and acylating agents were studied furnishing a practical and scalable green method useful for industrial applications. highly regioselective acylation and deacylation reactions with 1,2-dideoxy-d-ribose are described resulting in excellent yield. a fast, atom-efficient and convenient synthesis of 3-, and 5-o-dmtr-1,2-dideoxyribose 17 and 19 has been achieved. these compo ...201121748181
biosynthesis of novel polyhydroxyalkanoate containing 3-hydroxy-4-methylvalerate by chromobacterium sp. usm2.aims:ôçé polyhydroxyalkanoate (pha) with enhanced physicochemical properties will be ideal for a wide range of practical applications. the incorporation of 3-hydroxy-4-methylvalerate (3h4mv) into the polymer backbone is known to improve the overall properties of the resulting polymer. however, the most suitable micro-organism and pha synthase that can synthesize this monomer efficiently still remain unknown at present. therefore, we evaluated the abilities of a locally isolated chromobacterium s ...201121689225
genetic diversity study of chromobacterium violaceum isolated from kolli hills by amplified ribosomal dna restriction analysis (ardra) and random amplified polymorphic dna (rapd).aim:ôçé chromobacterium are saprophytes that cause highly fatal opportunistic infections. identification and strain differentiation were performed to identify the strain variability among the environmental samples. we have evaluated the suitability of individual and combined methods to detect the strain variations of the samples collected in different seasons. methods and results:ôçé amplified ribosomal dna restriction analysis (ardra) and random amplified polymorphic dna (rapd) profiles were ob ...201121726246
general metabolism of laribacter hongkongensis: a genome-wide analysis. 201121711917
plasmid encoded antibiotics inhibit protozoan predation of escherichia coli k12.bacterial plasmids and phages encode the synthesis of toxic molecules that inhibit protozoan predation. one such toxic molecule is violacein, a purple pigmented, anti-tumour antibiotic produced by the gram-negative soil bacterium chromobacterium violaceum. in the current experiments a range of escherichia coli k12 strains were genetically engineered to produce violacein and a number of its coloured, biosynthetic intermediates. a bactivorous predatory protozoan isolate, colpoda sp.a4, was isolate ...201121839110
Draft genome sequence of the biocontrol bacterium Chromobacterium sp. strain C-61.Chromobacterium sp. strain C-61 is a plant-associated bacterium with proven capacities to suppress plant diseases. Here, we report the draft genome sequence and automatic annotation of strain C-61. A comparison of this sequence to the sequenced genome of Chromobacterium violaceum ATCC 12472 indicates the novelty of C-61 and a subset of gene functions that may be related to its biocontrol activities.201122072653
chromobacterium violaceum infection: a clinical review of an important but neglected infection.increasing reported cases with chrombacterium violaceum infection has been noticed in recent decades. it is noteworthy for its difficult-to-treat entity characterized by a high frequency of sepsis, easily distantant metastasis, multidrug-resistance, and frequent relapse, and high mortality rate.201122036134
[screening and identification of marine fungi against bacterial quorum sensing].the discovery of quorum sensing (qs) system and its critical role in bacterial virulence have revealed a new way to attack pathogenic bacterium. the pathogenecity of qs deletion mutants decreases significantly. targeting bacterial qs system is a promising therapeutic approach to control infections and anti-microbial resistance. to obtain natural qs inhibitors from marine organisms, marine fungi (69 strains) were isolated from marine mollusca, and their extracts were screened using improved qsis2 ...201122117517
A novel property of propolis (bee glue): Anti-pathogenic activity by inhibition of N-acyl-homoserine lactone mediated signaling in bacteria.An alternative approach to antibiotics is the development of anti-pathogenic agents to control the bacterial virulome. Such anti-pathogenic agents could target a phenomena known as quorum sensing (QS).201122063726
indigenous soil bacteria with the combined potential for hydrocarbon consumption and heavy metal resistance.introduction: transconjugant bacteria with combined potential for hydrocarbon utilization and heavy metal resistance were suggested by earlier investigators for bioremediation of soils co-contaminated with hydrocarbons and heavy metals. the purpose of this study was to offer evidence that such microorganisms are already part of the indigenous soil microflora. methods: microorganisms in pristine and oily soils wer ...201121948132
detection of acylated homoserine lactones produced by vibrio spp. and related species isolated from water and aquatic organisms.aims:  to assess the diversity in production of acylated homoserine lactones (ahls) among vibrio spp and related species. methods and results:  a total of 106 isolates, with representatives of 28 vibrio spp and related species, were investigated for the production of ahls. for this, a rapid method for the screening of ahls was developed based on the use of bacterial biosensors using a double-layer microplate assay. at least one bacterial biosensor was activated in 20 species, agrobacterium tumef ...201122098208
Screening & profiling of quorum sensing signal molecules in Pseudomonas aeruginosa isolates from catheterized urinary tract infection patients.Catheter associated urinary tract infections are the second most common nosocomial infections and Pseudomonas aeruginosa is the third most common organism responsible for these infections. In this study P. aeruginosa isolates from catheterized urinary tract infection patients were screened and profiled for the presence of different type of quorum sensing (QS) signal molecules.201121911974
Biochemical characteristics and biological properties of annurca apple cider.Abstract Our work aimed to investigate the phenolic composition and antioxidant capacity of the de-alcoholized extract of cider obtained from the Annurca apple (Malus domestica var. Annurca). The antimicrobial effect of the extract against different pathogens, including Chronobacter sakazakii, was also examined. The extract's potential anti-quorum-sensing (AQS) activity was assessed using the test microorganism Chromobacterium violaceum. Biochemical analysis of the extract using ultra-performa ...201121861727
The NLRC4 inflammasome receptors for bacterial flagellin and type III secretion apparatus.Inflammasomes are large cytoplasmic complexes that sense microbial infections/danger molecules and induce caspase-1 activation-dependent cytokine production and macrophage inflammatory death. The inflammasome assembled by the NOD-like receptor (NLR) protein NLRC4 responds to bacterial flagellin and a conserved type III secretion system (TTSS) rod component. How the NLRC4 inflammasome detects the two bacterial products and the molecular mechanism of NLRC4 inflammasome activation are not understoo ...201121918512
Inhibition of marine biofouling by bacterial quorum sensing inhibitors.Seventy eight natural products from chemical libraries containing compounds from marine organisms (sponges, algae, fungi, tunicates and cyanobacteria) and terrestrial plants, were screened for the inhibition of bacterial quorum sensing (QS) using a reporter strain Chromobacterium violaceum CV017. About half of the natural products did not show any QS inhibition. Twenty four percent of the tested compounds inhibited QS of the reporter without causing toxicity. The QS inhibitory activities of the ...201121882898
Inhibition of Quorum Sensing in the Opportunistic Pathogenic Bacterium Chromobacterium violaceum by an Extract from Fruiting Bodies of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (W.Curt.:Fr.) P. Karst. (Higher Basidiomycetes).Extracts of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum, inhibited quorum sensing in Chromobacterium violaceum CV026. G. lucidum fruiting bodies were milled and extracted with ethyl acetate. The crude extract was dissolved in an appropriate concentration of methanol, sterilized by filtration through a 0.22-µm membrane filter, and added to Ch. Violaceum CV026 cultures, which were used as an indicator to monitor quorum sensing inhibition. Inhibitory activity was measured by quantifying ...201122181844
malabaricone c from myristica cinnamomea exhibits anti-quorum sensing activity.a methanol-soluble extract of the bark of myristica cinnamomea was found to exhibit anti-quorum sensing activity, and subsequent bioassay-guided isolation led to the identification of the active compound malabaricone c (1). compound 1 inhibited violacein production by chromobacterium violaceum cv026 when grown in the presence of a cognate signaling molecule, n-3-oxohexanoyl-homoserine lactone. furthermore, 1 inhibited the quorum sensing-regulated pyocyanin production and biofilm formation in pse ...201121910441
Chromobacterium violaceum lymphadenitis successfully treated in a Northern Italian hospital.Lymphadenitis can be caused by different gram positive and gram negative bacteria and non-tuberculous mycobacteria. Cervical lymphadenitis in children is thought to result from ingestion of or contact with environmental microrganisms. Chromobacterium violaceum is a common inhabitant of soil and water in tropical and sub tropical countries. In these parts of the world Chromobacterium violaceum is able to cause skin infection with diffuse pustular lesions and also multiple liver abscess with often ...201122143820
comparative biogeography of chromobacterium from the neotropics.the genus chromobacterium encompasses free-living gram-negative bacteria. until 2007, the genus consisted of only one species but six species are now recognized. chromobacterium violaceum is the type species of the genus and is commonly found in soil and water in tropical and sub-tropical regions. we have investigated a collection of 111 isolates displaying violet pigmentation from undisturbed aquatic and soil environments from brazilian cerrado ecosystem. the 16s rrna gene phylogeny revealed th ...201120803105
evidence for a high-spin fe(iv) species in the catalytic cycle of a bacterial phenylalanine hydroxylase.phenylalanine hydroxylase is a mononuclear non-heme iron protein that uses tetrahydropterin as the source of the two electrons needed to activate dioxygen for the hydroxylation of phenylalanine to tyrosine. rapid-quench methods have been used to analyze the mechanism of a bacterial phenylalanine hydroxylase from chromobacterium violaceum. mo¨ssbauer spectra of samples prepared by freeze-quenching the reaction of the enzyme-(57)fe(ii)-phenylalanine-6-methyltetrahydropterin complex with o(2) revea ...201121261288
novel and efficient copper-catalysed synthesis of nitrogen-linked medium-ring biaryls.herein, a new copper-catalysed strategy for the synthesis of rare nitrogen-linked seven-, eight- and nine-membered biaryl ring systems is described. it is proposed that the reaction proceeds through a highly activated intramolecularly co-ordinated copper catalyst. the process is technically simple, proceeds under relatively mild conditions, displays a broad substrate scope and forms biologically valuable products that are difficult to synthesise by other methods. we envisage that this methodolog ...201121290435
tannin-rich fraction from terminalia catappa inhibits quorum sensing (qs) in chromobacterium violaceum and the qs-controlled biofilm maturation and lasa staphylolytic activity in pseudomonas aeruginosa.the study aimed to test the activity of terminalia catappa l. against bacterial quorum sensing (qs) in order to provide a potential scientific basis for the traditional use of leaf extracts of this plant as an antiseptic.201121291979
long-chain acylhomoserine lactones increase the anoxic ammonium oxidation rate in an oland biofilm.the oxygen-limited autotrophic nitrification/denitrification (oland) process comprises one-stage partial nitritation and anammox, catalyzed by aerobic and anoxic ammonium-oxidizing bacteria (aeraob and anaob), respectively. the goal of this study was to investigate whether quorum sensing influences anoxic ammonium oxidation in an oland biofilm, with anaob colonizing 13% of the biofilm, as determined with fluorescent in situ hybridization (fish). at high biomass concentrations, the specific anoxi ...201121360147
biochemical and structural characterization of wlba from bordetella pertussis and chromobacterium violaceum: enzymes required for the biosynthesis of 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid.the unusual sugar 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid, or mannac3naca, has been observed in the lipopolysaccharides of both pathogenic and nonpathogenic gram-negative bacteria. it is added to the lipopolysaccharides of these organisms by glycosyltransferases that use as substrates udp-mannac3naca. five enzymes are ultimately required for the biosynthesis of udp-mannac3naca starting from udp-n-acetylglucosamine. the second enzyme in the pathway, encoded by the wlba gene and referred to ...201121241053
inhibition of quorum sensing in chromobacterium violaceum by pigments extracted from auricularia auricular.aims:  this study aimed to search for a novel quorum-sensing inhibitor from some fungi and analyse its inhibitory activity. methods and results:  chromobacterium violaceum cv026, a double mini-tn5 mutant, was used as an indicator to monitor quorum-sensing inhibition. auricularia auricular pigments from fruiting bodies were extracted using hydrochloric acid as an infusion, dissolved in alkaline dimethylsulfoxide (dmso), sterilized by filtration through a 0·22-μm membrane filter and added to c. vi ...201121241341
bioassays of quorum sensing compounds using agrobacterium tumefaciens and chromobacterium most bacteria, a global level of regulation exists involving intercellular communication via the production and response to cell density-dependent signal molecules. this cell density-dependent regulation has been termed quorum sensing (qs). qs is a global regulator, which has been associated with a number of important features in bacteria including virulence regulation and biofilm formation. consequently, there is considerable interest in understanding, detecting, and inhibiting qs. acyl homo ...201121031300
inhibition of quorum sensing in chromobacterium violaceum by pigments extracted from auricularia auricular.this study aimed to search for a novel quorum-sensing inhibitor from some fungi and analyse its inhibitory activity.201121204879
crystal structures of the chromobacterium violaceumω-transaminase reveal major structural rearrangements upon binding of coenzyme plp.summary: the bacterial ω-transaminase from chromobacterium violaceum (cv-ωta, ec catalyzes industrially important transamination reactions by use of the coenzyme pyridoxal 5'-phosphate (plp). here, we present four crystal structures of cv-ωta: two in the apo form, one in the holo form and one in an intermediate state, at resolutions between 1.35 and 2.4 å. the enzyme is a homodimer with a molecular weight of approximately 100 kda. each monomer has an active site at the dimeric interfac ...201222221622
evaluation of organically acceptable insecticides as stand-alone treatments and in rotation for managing yellowmargined leaf beetle, microtheca ochroloma (coleoptera: chrysomelidae), in organic crucifer production.background: yellowmargined leaf beetle, microtheca ochroloma, is the most damaging pest of organic crucifer crops in the southern united states. experiments were conducted over four growing seasons (2007-2010) in alabama to evaluate some botanical and microbial insecticides approved by the organic materials review institute (omri) against m. ochroloma in organically grown crucifer crops. insecticides evaluated included pyganic(®) (pyrethrum), aza-direct(®) (azadiractin), entrust(®) (spinosad) ...201222231993
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