| n-acyl homoserine lactones are degraded via an amidolytic activity in comamonas sp. strain d1. | comamonas strain d1 enzymatically inactivates quorum-sensing (qs) signal molecules of the n-acyl homoserine lactone (n-ahsl) family, and exhibits the broadest inactivation range of known bacteria. it degrades n-ahsl with acyl-side chains ranging from 4 to 16 carbons, with or without 3-oxo or 3-hydroxy substitutions. n-ahsl degradation yields hsl but not n-acyl homoserine: strain d1 therefore harbors an amidohydrolase activity. strain d1 is the fifth bacterium species in which an n-ahsl amidohydr ... | 2007 | 17136382 |
| characterization of the thermotoga maritima chemotaxis methylation system that lacks pentapeptide-dependent methyltransferase cher:mcp tethering. | sensory adaptation in bacterial chemotaxis is mediated by covalent modifications of specific glutamate and glutamine residues within the cytoplasmic domains of methyl-accepting chemotaxis proteins (mcps). in escherichia coli and salmonella enterica, efficient methylation of mcps depends on the localization of methyltransferase cher to mcp clusters through an interaction between the cher beta-subdomain and a pentapeptide sequence (nwetf or nwesf) at the c-terminus of the mcp. in vitro methylation ... | 2007 | 17163981 |
| characterization of the thermotoga maritima chemotaxis methylation system that lacks pentapeptide-dependent methyltransferase cher:mcp tethering. | sensory adaptation in bacterial chemotaxis is mediated by covalent modifications of specific glutamate and glutamine residues within the cytoplasmic domains of methyl-accepting chemotaxis proteins (mcps). in escherichia coli and salmonella enterica, efficient methylation of mcps depends on the localization of methyltransferase cher to mcp clusters through an interaction between the cher beta-subdomain and a pentapeptide sequence (nwetf or nwesf) at the c-terminus of the mcp. in vitro methylation ... | 2007 | 17163981 |
| high precision multi-genome scale reannotation of enzyme function by eficaz. | the functional annotation of most genes in newly sequenced genomes is inferred from similarity to previously characterized sequences, an annotation strategy that often leads to erroneous assignments. we have performed a reannotation of 245 genomes using an updated version of eficaz, a highly precise method for enzyme function prediction. | 2006 | 17166279 |
| the serratia-type hemolysin of chromobacterium violaceum. | chromobacterium violaceum is a gram-negative opportunistic human pathogen and an inhabitant of tropical soils and waterways. although known primarily for the synthesis of the pigment violacein, and more recently as a reporter strain for quorum sensing, clinical reports of chromobacteriosis comprise the largest block of published literature on this organism. genome sequencing has revealed many potential virulence factors in this microorganism, and this paper establishes the presence in c. violace ... | 2007 | 17169000 |
| the pseudomonas quorum-sensing regulator rsal belongs to the tetrahelical superclass of h-t-h proteins. | in the opportunistic human pathogen pseudomonas aeruginosa, quorum sensing (qs) is crucial for virulence. the rsal protein directly represses the transcription of lasi, the synthase gene of the main qs signal molecule. on the basis of sequence homology, rsal cannot be predicted to belong to any class of characterized dna-binding proteins. in this study, an in silico model of the rsal structure was inferred showing that rsal belongs to the tetrahelical superclass of helix-turn-helix proteins. the ... | 2007 | 17172347 |
| the pseudomonas quorum-sensing regulator rsal belongs to the tetrahelical superclass of h-t-h proteins. | in the opportunistic human pathogen pseudomonas aeruginosa, quorum sensing (qs) is crucial for virulence. the rsal protein directly represses the transcription of lasi, the synthase gene of the main qs signal molecule. on the basis of sequence homology, rsal cannot be predicted to belong to any class of characterized dna-binding proteins. in this study, an in silico model of the rsal structure was inferred showing that rsal belongs to the tetrahelical superclass of helix-turn-helix proteins. the ... | 2007 | 17172347 |
| in vitro biosynthesis of violacein from l-tryptophan by the enzymes vioa-e from chromobacterium violaceum. | the purple chromobacterial pigment violacein arises by enzymatic oxidation and coupling of two molecules of l-tryptophan to give a rearranged pyrrolidone-containing scaffold in the final pigment. we have purified five contiguously encoded proteins vioa-e after expression in escherichia coli and demonstrate the full 14-electron oxidation pathway to yield the final chromophore. the flavoenzyme vioa and the heme protein viob work in conjunction to oxidize and dimerize l-tryptophan to a nascent prod ... | 2006 | 17176066 |
| secrets of soil survival revealed by the genome sequence of arthrobacter aurescens tc1. | arthrobacter sp. strains are among the most frequently isolated, indigenous, aerobic bacterial genera found in soils. member of the genus are metabolically and ecologically diverse and have the ability to survive in environmentally harsh conditions for extended periods of time. the genome of arthrobacter aurescens strain tc1, which was originally isolated from soil at an atrazine spill site, is composed of a single 4,597,686 basepair (bp) circular chromosome and two circular plasmids, ptc1 and p ... | 2006 | 17194220 |
| phylogenetic tree information aids supervised learning for predicting protein-protein interaction based on distance matrices. | protein-protein interactions are critical for cellular functions. recently developed computational approaches for predicting protein-protein interactions utilize co-evolutionary information of the interacting partners, e.g., correlations between distance matrices, where each matrix stores the pairwise distances between a protein and its orthologs from a group of reference genomes. | 2007 | 17212819 |
| characterization of campylobacter jejuni biofilms under defined growth conditions. | campylobacter jejuni is a major cause of human diarrheal disease in many industrialized countries and is a source of public health and economic burden. c. jejuni, present as normal flora in the intestinal tract of commercial broiler chickens and other livestock, is probably the main source of human infections. the presence of c. jejuni in biofilms found in animal production watering systems may play a role in the colonization of these animals. we have determined that c. jejuni can form biofilms ... | 2007 | 17259368 |
| crystallization and preliminary x-ray diffraction analysis of omega-amino acid:pyruvate transaminase from chromobacterium violaceum. | the enzyme omega-transaminase catalyses the conversion of chiral omega-amines to ketones. the recombinant enzyme from chromobacterium violaceum has been purified to homogeneity. the enzyme was crystallized from peg 4000 using the microbatch method. data were collected to 1.7 a resolution from a crystal belonging to the triclinic space group p1, with unit-cell parameters a = 58.9, b = 61.9, c = 63.9 a, alpha = 71.9, beta = 87.0, gamma = 74.6 degrees . data were also collected to 1.95 a from a sec ... | 2007 | 17277454 |
| a complete set of flagellar genes acquired by horizontal transfer coexists with the endogenous flagellar system in rhodobacter sphaeroides. | bacteria swim in liquid environments by means of a complex rotating structure known as the flagellum. approximately 40 proteins are required for the assembly and functionality of this structure. rhodobacter sphaeroides has two flagellar systems. one of these systems has been shown to be functional and is required for the synthesis of the well-characterized single subpolar flagellum, while the other was found only after the genome sequence of this bacterium was completed. in this work we found th ... | 2007 | 17293429 |
| yeast functional genomic screens lead to identification of a role for a bacterial effector in innate immunity regulation. | numerous bacterial pathogens manipulate host cell processes to promote infection and ultimately cause disease through the action of proteins that they directly inject into host cells. identification of the targets and molecular mechanisms of action used by these bacterial effector proteins is critical to understanding pathogenesis. we have developed a systems biological approach using the yeast saccharomyces cerevisiae that can expedite the identification of cellular processes targeted by bacter ... | 2007 | 17305427 |
| a fatal case of chromobacterium violaceum septicemia in hong kong. | chromobacterium violaceum causes a rare infection in human, usually in tropical or subtropical areas. we report a fatal case of c. violaceum infection affecting a 40-year-old previously healthy man in hong kong. he presented with a wound infection and lymphadenitis. despite multiple antibiotic treatment, including ciprofloxacin, he succumbed shortly after admission to the hospital. we report the epidemiological investigation findings and discuss the possible sources of infection. physicians shou ... | 2006 | 17333774 |
| actively growing bacteria in the inland sea of japan, identified by combined bromodeoxyuridine immunocapture and denaturing gradient gel electrophoresis. | a fundamental question in microbial oceanography concerns the relationship between prokaryote diversity and biogeochemical function in an ecosystem context. we combined bromodeoxyuridine (brdu) magnetic bead immunocapture and pcr-denaturing gradient gel electrophoresis (bump-dgge) to examine phylotype-specific growth in natural marine assemblages. we also examined a broad range of marine bacterial isolates to determine their abilities to incorporate brdu in order to test the validity of the meth ... | 2007 | 17337555 |
| genome analysis of dna repair genes in the alpha proteobacterium caulobacter crescentus. | the integrity of dna molecules is fundamental for maintaining life. the dna repair proteins protect organisms against genetic damage, by removal of dna lesions or helping to tolerate them. dna repair genes are best known from the gamma-proteobacterium escherichia coli, which is the most understood bacterial model. however, genome sequencing raises questions regarding uniformity and ubiquity of these dna repair genes and pathways, reinforcing the need for identifying genes and proteins, which may ... | 2007 | 17352799 |
| stereochemical course of tryptophan dehydrogenation during biosynthesis of the calcium-dependent lipopeptide antibiotics. | [reaction: see text] hydrogen atoms are abstracted from the c2' and c3'-pro-s positions of an (s)-tryptophanyl precursor, with overall syn stereochemistry, during the biosynthesis of the c-terminal z-2',3'-dehydrotryptophan residue of the calcium-dependent lipopeptide antibiotics (cdas) in streptomyces coelicolor. the absence of beta-hydroxytryptophanyl, or other possible intermediates, further suggests a direct dehydrogenation mechanism similar to that proposed for the l-tryptophan 2',3'-oxidas ... | 2007 | 17355143 |
| quorum-sensing regulation in rhizobia and its role in symbiotic interactions with legumes. | legume-nodulating bacteria (rhizobia) usually produce n-acyl homoserine lactones, which regulate the induction of gene expression in a quorum-sensing (or population-density)-dependent manner. there is significant diversity in the types of quorum-sensing regulatory systems that are present in different rhizobia and no two independent isolates worked on in detail have the same complement of quorum-sensing genes. the genes regulated by quorum sensing appear to be rather diverse and many are associa ... | 2007 | 17360278 |
| the effect of quorum-sensing blockers on the formation of marine microbial communities and larval attachment. | we studied the effect of the quorum-sensing (qs) blockers 5-hydroxy-3[(1r)-1-hydroxypropyl]-4-methylfuran-2(5h)-one (fur1), (5r)-3,4-dihydroxy-5-[(1s)-1,2-dihydroxyethyl]furan-2(5h)-one (fur2) and triclosan (tri) on the formation of bacterial biofilms, and the effect of these biofilms on the larval attachment of the polychaete hydroides elegans and the bryozoan bugula neritina. 14-day-old subtidal biofilms were harvested from artificial substrata and were allowed to develop in the laboratory wit ... | 2007 | 17371321 |
| phenotypic characterization of clonal and nonclonal pseudomonas aeruginosa strains isolated from lungs of adults with cystic fibrosis. | the emergence of virulent pseudomonas aeruginosa clones is a threat to cystic fibrosis (cf) patients globally. characterization of clonal p. aeruginosa strains is critical for an understanding of its clinical impact and developing strategies to meet this problem. two clonal strains (aes-1 and aes-2) are circulating within cf centers in eastern australia. in this study, phenotypic characteristics of 43 (14 aes-1, 5 aes-2, and 24 nonclonal) p. aeruginosa isolates were compared to gain insight into ... | 2007 | 17392437 |
| genetic organization of the biosynthetic gene cluster for the indolocarbazole k-252a in nonomuraea longicatena jcm 11136. | indolocarbazole metabolite k-252a is a natural product that was previously reported as a potent protein kinase c inhibitor with in vitro and in vivo potency. from a biosynthetic viewpoint, this compound possesses structurally interesting features such as an unusual furanosyl sugar moiety, which are absent in the well-studied staurosporine and rebeccamycin. a cosmid library from genomic dna of nonomuraea longicatena jcm 11136 was constructed and screened for the presence of genes to be involved i ... | 2007 | 17396254 |
| characterization of a gene cluster responsible for the biosynthesis of anticancer agent fk228 in chromobacterium violaceum no. 968. | a gene cluster responsible for the biosynthesis of anticancer agent fk228 has been identified, cloned, and partially characterized in chromobacterium violaceum no. 968. first, a genome-scanning approach was applied to identify three distinctive c. violaceum no. 968 genomic dna clones that code for portions of nonribosomal peptide synthetase and polyketide synthase. next, a gene replacement system developed originally for pseudomonas aeruginosa was adapted to inactivate the genomic dna-associated ... | 2007 | 17400765 |
| signal mimics derived from a metagenomic analysis of the gypsy moth gut microbiota. | bacterial signaling is an important part of community life, but little is known about the signal transduction pathways of the as-yet-uncultured members of microbial communities. to address this gap, we aimed to identify genes directing the synthesis of signals in uncultured bacteria associated with the midguts of gypsy moth larvae. we constructed a metagenomic library consisting of dna extracted directly from the midgut microbiota and analyzed it using an intracellular screen designated metrex, ... | 2007 | 17435000 |
| thermoregulation of n-acyl homoserine lactone-based quorum sensing in the soft rot bacterium pectobacterium atrosepticum. | the psychrotolerant bacterium pectobacterium atrosepticum produces four n-acyl homoserine lactones under a wide range of temperatures. their thermoregulation differs from that of the exoenzyme production, described as being under quorum-sensing control. a mechanism involved in this thermoregulation consists of controlling n-acyl homoserine lactones synthase production at a transcriptional level. | 2007 | 17468275 |
| chromobacterium subtsugae sp. nov., a betaproteobacterium toxic to colorado potato beetle and other insect pests. | strain praa4-1(t), a motile, gram-negative, violet-pigmented bacterium, was isolated from maryland forest soil and found to be orally toxic to colorado potato beetle larvae and other insects. morphological, biological, biochemical and molecular characterization revealed that this strain was most similar to chromobacterium violaceum, the type species and only currently recognized member of the genus chromobacterium. dna-dna hybridization with c. violaceum atcc 12472(t) was 27 %. phylogenetic anal ... | 2007 | 17473247 |
| gulbenkiania mobilis gen. nov., sp. nov., isolated from treated municipal wastewater. | a bacterial strain (e4fc31(t)) isolated from treated municipal wastewater was characterized phenotypically and phylogenetically. cells were gram-negative, curved rods with a polar flagellum. the isolate was catalase-, oxidase- and arginine dihydrolase-positive, and able to grow between 15 and 45 degrees c and between ph 5.5 and 9.0. the predominant fatty acids were c(16 : 1)/iso-c(15 : 0) 2-oh and c(16 : 0), the major respiratory quinone was ubiquinone 8 and the g+c content of the genomic dna wa ... | 2007 | 17473267 |
| dietary phytochemicals as quorum sensing inhibitors. | quorum sensing (qs) is a cell density dependent expression of species in bacteria mediated by hormone like compounds called autoinducers (ai). several processes responsible for successful establishment of bacterial infection are mediated by qs. inhibition of qs is therefore being considered as a new target for antimicrobial chemotherapy. dietary phytochemicals are secondary metabolites in plants known to have several health benefits including antimicrobial activity. however, their ability to inh ... | 2007 | 17499938 |
| gene cloning and characterization of the very large nad-dependent l-glutamate dehydrogenase from the psychrophile janthinobacterium lividum, isolated from cold soil. | nad-dependent l-glutamate dehydrogenase (nad-gdh) activity was detected in cell extract from the psychrophile janthinobacterium lividum utb1302, which was isolated from cold soil and purified to homogeneity. the native enzyme (1,065 kda, determined by gel filtration) is a homohexamer composed of 170-kda subunits (determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis). consistent with these findings, gene cloning and sequencing enabled deduction of the amino acid sequence of the ... | 2007 | 17526698 |
| engineering of pa-iil lectin from pseudomonas aeruginosa - unravelling the role of the specificity loop for sugar preference. | lectins are proteins of non-immune origin capable of binding saccharide structures with high specificity and affinity. considering the high encoding capacity of oligosaccharides, this makes lectins important for adhesion and recognition. the present study is devoted to the pa-iil lectin from pseudomonas aeruginosa, an opportunistic human pathogen capable of causing lethal complications in cystic fibrosis patients. the lectin may play an important role in the process of virulence, recognizing spe ... | 2007 | 17540045 |
| quorum sensing has an unexpected role in virulence in the model pathogen citrobacter rodentium. | the bacterial mouse pathogen citrobacter rodentium causes attaching and effacing (ae) lesions in the same manner as pathogenic escherichia coli, and is an important model for this mode of pathogenesis. quorum sensing (qs) involves chemical signalling by bacteria to regulate gene expression in response to cell density. e. coli has never been reported to have n-acylhomoserine lactone (ahl) qs, but it does utilize luxs-dependent signalling. we found production of ahl qs signalling molecules by an a ... | 2007 | 17557113 |
| involvement of a quorum-sensing-regulated lipase secreted by a clinical isolate of burkholderia glumae in severe disease symptoms in rice. | burkholderia glumae is an emerging rice pathogen in several areas around the world. closely related burkholderia species are important opportunistic human pathogens for specific groups of patients, such as patients with cystic fibrosis and patients with chronic granulomatous disease. here we report that the first clinical isolate of b. glumae, strain au6208, has retained its capability to be very pathogenic to rice. as previously reported for rice isolate b. glumae bgr1 (and also for the clinica ... | 2007 | 17557855 |
| analysis of chromobacterium sp. natural isolates from different brazilian ecosystems. | chromobacterium violaceum is a free-living bacterium able to survive under diverse environmental conditions. in this study we evaluate the genetic and physiological diversity of chromobacterium sp. isolates from three brazilian ecosystems: brazilian savannah (cerrado), atlantic rain forest and amazon rain forest. we have analyzed the diversity with molecular approaches (16s rrna gene sequences and amplified ribosomal dna restriction analysis) and phenotypic surveys of antibiotic resistance and b ... | 2007 | 17584942 |
| inhibition of quorum sensing-regulated behaviors by scorzonera sandrasica. | many gram-negative bacteria use n-acyl homoserine lactone signal molecules to monitor their own population density and coordinate gene regulation in a process called quorum sensing (qs). increasing evidence implies that certain eukaryotes produce qs-inhibitory compounds. in this work, we tested 46 terrestrial plants materials for their ability to inhibit qs-regulated behaviors in different bacterial species. plant materials were dried and extracted using different solvents. the chloroform-solubl ... | 2007 | 17597339 |
| bartonella quintana lipopolysaccharide is a natural antagonist of toll-like receptor 4. | bartonella quintana is a gram-negative microorganism that causes trench fever and chronic bacteremia. b. quintana lipopolysaccharide (lps) was unable to induce the production of proinflammatory cytokines in human monocytes. interestingly, b. quintana lps is a potent antagonist of toll-like receptor 4 (tlr4), as it inhibited both mrna transcription and the release of tumor necrosis factor alpha, interleukin 1beta (il-1beta), and il-6 by escherichia coli lps in human monocytes, at ratios ranging f ... | 2007 | 17606598 |
| identification of aeromonas veronii genes required for colonization of the medicinal leech, hirudo verbana. | most digestive tracts contain a complex consortium of beneficial microorganisms, making it challenging to tease apart the molecular interactions between symbiont and host. the digestive tract of hirudo verbana, the medicinal leech, is an ideal model system because it harbors a simple microbial community in the crop, comprising the genetically amenable aeromonas veronii and a rikenella-like bacterium. signature-tagged mutagenesis (stm) was used to identify genes required for digestive tract colon ... | 2007 | 17616592 |
| chromobacterium violaceum infection in taiwan: a case report and literature review. | chromobacterium violaceum is a facultative anaerobic, gram-negative bacillus which inhabits stagnant water in tropical and subtropical regions. we describe the case of an 80-year-old female patient with c. violaceum bacteremia due to traumatic wound infected by contaminated water and soil. she had persistent fever, hypotension and neutrophilic leukocytosis on admission. two sets of blood cultures yielded c. violaceum. the patient was successfully treated with levofloxacin. since the first case f ... | 2007 | 17639170 |
| multidrug resistant chromobacterium violaceum: an unusual bacterium causing long standing wound abscess. | | 2003 | 17643028 |
| pqsa is required for the biosynthesis of 2,4-dihydroxyquinoline (dhq), a newly identified metabolite produced by pseudomonas aeruginosa and burkholderia thailandensis. | a new metabolite, 2,4-dihydroxyquinoline (dhq), was identified in cultures of the bacteria pseudomonas aeruginosa and burkholderia thailandensis. we found that the biosynthesis of dhq correlates with the presence of a functional pqsa, which is a product of the pqsabcde operon responsible for the synthesis of 4-hydroxy-2-alkylquinolines (haqs) in p. aeruginosa. however, dhq is not a degradation product or precursor of haqs. this finding sheds some light on the poorly understood biosynthesis pathw ... | 2007 | 17655503 |
| the pseudomonas putida lon protease is involved in n-acyl homoserine lactone quorum sensing regulation. | in pseudomonas putida and pseduomonas aeruginosa, the similar ppur/rsal/ppui and lasr/rsal/lasi acyl homoserine lactones (ahls) quorum sensing (qs) systems have been shown to be under considerable regulation by other global regulators. a major regulator is the rsal protein which strongly directly represses the transcription of the p. putida ppui and p. aeruginosa lasi ahl synthases. in this study we screened a transposon mutant bank of p. putida in order to identify if any other regulators were ... | 2007 | 17655747 |
| inhibition of quorum sensing in serratia marcescens as-1 by synthetic analogs of n-acylhomoserine lactone. | quorum sensing is a regulatory system for controlling gene expression in response to increasing cell density. n-acylhomoserine lactone (ahl) is produced by gram-negative bacteria, which use it as a quorum-sensing signal molecule. serratia marcescens is a gram-negative opportunistic pathogen which is responsible for an increasing number of serious nosocomial infections. s. marcescens as-1 produces n-hexanoyl homoserine lactone (c(6)-hsl) and n-(3-oxohexanoyl) homoserine lactone and regulates prod ... | 2007 | 17675425 |
| biofilm interactions between distinct bacterial genera isolated from drinking water. | in the environment, multiple microorganisms coexist as communities, competing for resources and often associated as biofilms. in this study, single- and dual-species biofilm formation by, and specific activities of, six heterotrophic intergeneric bacteria were determined using 96-well polystyrene plates over a 72-h period. these bacteria were isolated from drinking water and identified by partial 16s rrna gene sequencing. a series of planktonic studies was also performed, assessing the bacterial ... | 2007 | 17675433 |
| one step engineering of t7-expression strains for protein production: increasing the host-range of the t7-expression system. | the t7-expression system has been very useful for protein expression in escherichia coli. however, it is often desirable to over-express proteins in species other than e. coli. here, we constructed an inducible broad-host-range t7-expression transposon, which allows simple one-step construction of t7-expression strains in various species, providing the option to over-express proteins of interest in a broader host-range. this transposon contains the t7 rna polymerase driven by the lacuv5 promoter ... | 2007 | 17716915 |
| bacterial stimulation of sporangium production in phytophthora cinnamomi. | bacteria, notably chromobacterium violaceum, stimulate initiation of production of sporangia by phytophthora cinnamomi, a plant pathogen which does not produce this asexual stage in ordinary agar or liquid culture. | 1965 | 17742598 |
| a generalized transducing phage for the murine pathogen citrobacter rodentium. | a virulent phage (phicr1) capable of generalized transduction in citrobacter rodentium was isolated from the environment and characterized. c. rodentium is a natural pathogen of mice, causing transmissible murine colonic hyperplasia. sequencing of its genome has recently been completed and will soon be fully annotated and published. c. rodentium is an important model organism for infections caused by the human pathogens enteropathogenic and enterohaemorrhagic escherichia coli (epec and ehec). ph ... | 2007 | 17768241 |
| host-plant selectivity of rhizobacteria in a crop/weed model system. | belowground microorganisms are known to influence plants' performance by altering the soil environment. plant pathogens such as cyanide-producing strains of the rhizobacterium pseudomonas may show strong host-plant selectivity. we analyzed interactions between different host plants and pseudomonas strains and tested if these can be linked to the cyanide sensitivity of host plants, the cyanide production of bacterial strains or the plant identity from which strains had been isolated. eight strain ... | 2007 | 17786217 |
| accuracy of burkholderia pseudomallei identification using the api 20ne system and a latex agglutination test. | in an evaluation of the api 20ne for the identification of burkholderia spp., 792/800 (99%) burkholderia pseudomallei and 17/19 (89%) b. cepacia isolates were correctly identified but 10 b. mallei and 98 b. thailandensis isolates were not correctly identified. a latex agglutination test was positive for 796/800 (99.5%) b. pseudomallei isolates and negative for 120 other oxidase-positive gram-negative bacilli. | 2007 | 17804660 |
| the plant pathogen pantoea ananatis produces n-acylhomoserine lactone and causes center rot disease of onion by quorum sensing. | a number of gram-negative bacteria have a quorum-sensing system and produce n-acyl-l-homoserine lactone (ahl) that they use them as a quorum-sensing signal molecule. pantoea ananatis is reported as a common colonist of wheat heads at ripening and causes center rot of onion. in this study, we demonstrated that p. ananatis sk-1 produced two ahls, n-hexanoyl-l-homoserine lactone (c6-hsl) and n-(3-oxohexanoyl)-l-homoserine lactone (3-oxo-c6-hsl). we cloned the ahl-synthase gene (eani) and ahl-recept ... | 2007 | 17827290 |
| genome sequence analysis of the emerging human pathogenic acetic acid bacterium granulibacter bethesdensis. | chronic granulomatous disease (cgd) is an inherited immune deficiency characterized by increased susceptibility to infection with staphylococcus, certain gram-negative bacteria, and fungi. granulibacter bethesdensis, a newly described genus and species within the family acetobacteraceae, was recently isolated from four cgd patients residing in geographically distinct locales who presented with fever and lymphadenitis. we sequenced the genome of the reference strain of granulibacter bethesdensis, ... | 2007 | 17827295 |
| physiological ecology of stenoxybacter acetivorans, an obligate microaerophile in termite guts. | stenoxybacter acetivorans is a newly described, obligately microaerophilic beta-proteobacterium that is abundant in the acetate-rich hindgut of reticulitermes. here we tested the hypotheses that cells are located in the hypoxic, peripheral region of reticulitermes flavipes hindguts and use acetate to fuel their o(2)-consuming respiratory activity in situ. physical fractionation of r. flavipes guts, followed by limited-cycle pcr with s. acetivorans-specific 16s rrna gene primers, indicated that c ... | 2007 | 17827335 |
| evaluation of different compounds as quorum sensing inhibitors in pseudomonas aeruginosa. | quorum sensing (qs) controls systems affecting the pathogenicity of many microorganisms; its interruption has an anti-pathogenic effect and can be used in the treatment of bacterial infections. in this study we evaluated qs regulation by pseudomonas aeruginosa strains and qs inhibition (qsi) by different compounds. the inhibitory activity of 3 macrolide and 3 lincosamide drugs, resveratrol, garlic extract and n-acetylcysteine was tested on 4 p. aeruginosa strains isolated from cystic fibrosis (c ... | 2007 | 17855182 |
| quorum sensing: fact, fiction, and everything in between. | | 2007 | 17869606 |
| sepsis by chromobacterium violaceum: first case report from colombia. | chromobacterium violaceum is found in tropical and subtropical regions; it is the only chromobacterium species pathogenic for humans. due to its rare presentation, physicians often ignore the importance of this pathogen. we report a fulminant fatal case of bacteremia in a 38-year-old colombian man. the clinical manifestations were fever, thoracic pain, respiratory failure and death. his condition, from the beginning of clinical diagnosis, went into continuous deterioration, till his death, withi ... | 2007 | 17874003 |
| the ralstonia solanacearum pathogenicity regulator hrpb induces 3-hydroxy-oxindole synthesis. | the transcriptional activator hrpb of the bacterial wilt causing betaproteobacterium ralstonia solanacearum represents a key regulator for pathogenicity. in particular, it drives expression of hrp genes encoding a type iii secretion system (t3ss) as well as effector molecules for delivery into the host cytosol to promote disease. however, the hrpb regulon extends beyond this t3ss. we describe here an hrpb-activated operon of six genes that is responsible for the synthesis of a fluorescent isatin ... | 2007 | 17890323 |
| [chromobacterium violaceum septicemia: first case report in the french west indies]. | we report a fatal case of chromobacterium violaceum septicemia in a 42-year-old farm worker living in the french west indies. the bacteria found in the muddy soil and the stagnant water of tropical and subtropical regions is rarely a source of human infection. | 2007 | 17905550 |
| n-(3-hydroxyhexanoyl)-l-homoserine lactone is the biologically relevant quormone that regulates the phz operon of pseudomonas chlororaphis strain 30-84. | phenazine production by pseudomonas fluorescens 2-79 and p. chlororaphis isolates 30-84 and pcl1391 is regulated by quorum sensing through the activator phzr and acyl-homoserine lactones (acyl-hsls) synthesized by phzi. phzi from p. fluorescens 2-79 produces five acyl-hsls that include four 3-hydroxy species. of these, n-(3-hydroxyhexanoyl)-hsl is the biologically relevant ligand for phzr. the quorum-sensing systems of p. chlororaphis strains 30-84 and pcl1391 have been reported to produce and r ... | 2007 | 17921283 |
| evolution and functional characterization of the rh50 gene from the ammonia-oxidizing bacterium nitrosomonas europaea. | the family of ammonia and ammonium channel proteins comprises the amt proteins, which are present in all three domains of life with the notable exception of vertebrates, and the homologous rh proteins (rh50 and rh30) that have been described thus far only in eukaryotes. the existence of an rh50 gene in bacteria was first revealed by the genome sequencing of the ammonia-oxidizing bacterium nitrosomonas europaea. here we have used a phylogenetic approach to study the evolution of the n. europaea r ... | 2007 | 17921289 |
| inhibition of quorum sensing-controlled virulence factor production in pseudomonas aeruginosa by south florida plant extracts. | quorum sensing (qs) is a key regulator of virulence and biofilm formation in pseudomonas aeruginosa and other medically relevant bacteria. aqueous extracts of six plants, conocarpus erectus, chamaesyce hypericifolia, callistemon viminalis, bucida buceras, tetrazygia bicolor, and quercus virginiana, were examined in this study for their effects on p. aeruginosa virulence factors and the qs system. c. erectus, b. buceras, and c. viminalis caused a significant inhibition of lasa protease, lasb elas ... | 2008 | 17938186 |
| inhibition of quorum sensing-controlled virulence factor production in pseudomonas aeruginosa by south florida plant extracts. | quorum sensing (qs) is a key regulator of virulence and biofilm formation in pseudomonas aeruginosa and other medically relevant bacteria. aqueous extracts of six plants, conocarpus erectus, chamaesyce hypericifolia, callistemon viminalis, bucida buceras, tetrazygia bicolor, and quercus virginiana, were examined in this study for their effects on p. aeruginosa virulence factors and the qs system. c. erectus, b. buceras, and c. viminalis caused a significant inhibition of lasa protease, lasb elas ... | 2008 | 17938186 |
| luxri homologs are universally present in the genus aeromonas. | aeromonas spp. have been regarded as "emerging pathogens". aeromonads possess multifactorial virulence and the production of many of these virulence determinants is associated with high cell density, a phenomenon that might be regulated by quorum sensing. however, only two species of the genus are reported to possess the luxri quorum sensing gene homologs. the purpose of this study was to investigate if the luxri homologs are universally present in the aeromonas strains collected from various cu ... | 2007 | 17953777 |
| signature-tagged mutagenesis of edwardsiella ictaluri identifies virulence-related genes, including a salmonella pathogenicity island 2 class of type iii secretion systems. | edwardsiella ictaluri is the leading cause of mortality in channel catfish culture, but little is known about its pathogenesis. the use of signature-tagged mutagenesis in a waterborne infection model resulted in the identification of 50 mutants that were unable to infect/survive in catfish. nineteen had minitransposon insertions in miscellaneous genes in the chromosome, 10 were in genes that matched to hypothetical proteins, and 13 were in genes that had no significant matches in the ncbi databa ... | 2007 | 17965213 |
| isolation and characterization of two groups of novel marine bacteria producing violacein. | thirteen strains of novel marine bacteria producing a purple pigment were isolated from the pacific coast of japan. they were divided into two groups based on their 16s ribosomal rna gene sequences, and both groups of bacteria belonged to the genus pseudoalteromonas. the uv-visible spectrum of the pigment was identical to those of violacein, a pigment produced by several species of bacteria including chromobacterium violaceum, an opportunistic pathogen. further analysis of the chemical structure ... | 2008 | 17968625 |
| the nlee/ospz family of effector proteins is required for polymorphonuclear transepithelial migration, a characteristic shared by enteropathogenic escherichia coli and shigella flexneri infections. | enteropathogenic escherichia coli (epec) and shigella flexneri are human host-specific pathogens that infect intestinal epithelial cells. however, each bacterial species employs a different infection strategy within this environmental niche. epec attaches to the apical surface of small intestine enterocytes, causing microvillus effacement and rearrangement of the host cell cytoskeleton beneath adherent bacteria. in contrast, s. flexneri invades the large intestine epithelium at the basolateral m ... | 2008 | 17984206 |
| the nlee/ospz family of effector proteins is required for polymorphonuclear transepithelial migration, a characteristic shared by enteropathogenic escherichia coli and shigella flexneri infections. | enteropathogenic escherichia coli (epec) and shigella flexneri are human host-specific pathogens that infect intestinal epithelial cells. however, each bacterial species employs a different infection strategy within this environmental niche. epec attaches to the apical surface of small intestine enterocytes, causing microvillus effacement and rearrangement of the host cell cytoskeleton beneath adherent bacteria. in contrast, s. flexneri invades the large intestine epithelium at the basolateral m ... | 2008 | 17984206 |
| [sepsis caused by pigmented and no pigmented chromobacterium violaceum]. | chromobacterium violaceum sepsis is rare but associated with a high mortality rate. we report a fatal case of c. violaceum sepsis in a 6 years old venezuelan indian boy. clinical manifestations were fever and swelling in the right inguinal region. the initial diagnosis was an appendicular plastron. appendicectomy was performed and during surgery a right psoas abscess was identified that resulted culture positive for pigmented c. violaceum. blood cultures were positive for a pigmented and non pig ... | 2007 | 17989847 |
| massetolide a biosynthesis in pseudomonas fluorescens. | massetolide a is a cyclic lipopeptide (clp) antibiotic produced by various pseudomonas strains from diverse environments. cloning, sequencing, site-directed mutagenesis, and complementation showed that massetolide a biosynthesis in p. fluorescens ss101 is governed by three nonribosomal peptide synthetase (nrps) genes, designated massa, massb, and massc, spanning approximately 30 kb. prediction of the nature and configuration of the amino acids by in silico analysis of adenylation and condensatio ... | 2008 | 17993540 |
| massetolide a biosynthesis in pseudomonas fluorescens. | massetolide a is a cyclic lipopeptide (clp) antibiotic produced by various pseudomonas strains from diverse environments. cloning, sequencing, site-directed mutagenesis, and complementation showed that massetolide a biosynthesis in p. fluorescens ss101 is governed by three nonribosomal peptide synthetase (nrps) genes, designated massa, massb, and massc, spanning approximately 30 kb. prediction of the nature and configuration of the amino acids by in silico analysis of adenylation and condensatio ... | 2008 | 17993540 |
| identification of prophages in bacterial genomes by dinucleotide relative abundance difference. | prophages are integrated viral forms in bacterial genomes that have been found to contribute to interstrain genetic variability. many virulence-associated genes are reported to be prophage encoded. present computational methods to detect prophages are either by identifying possible essential proteins such as integrases or by an extension of this technique, which involves identifying a region containing proteins similar to those occurring in prophages. these methods suffer due to the problem of l ... | 2007 | 18030328 |
| comparison of genomes of three xanthomonas oryzae bacteriophages. | xp10 and op1 are phages of xanthomonas oryzae pv. oryzae (xoo), the causative agent of bacterial leaf blight in rice plants, which were isolated in 1967 in taiwan and in 1954 in japan, respectively. we recently isolated the xoo phage xop411. | 2007 | 18045507 |
| the guanine-nucleotide-exchange factor bope from burkholderia pseudomallei adopts a compact version of the salmonella sope/sope2 fold and undergoes a closed-to-open conformational change upon interaction with cdc42. | bope is a type iii secreted protein from burkholderia pseudomallei, the aetiological agent of melioidosis, a severe emerging infection. bope is a gef (guanine-nucleotide-exchange factor) for the rho gtpases cdc42 (cell division cycle 42) and rac1. we have determined the structure of bope catalytic domain (amino acids 78-261) by nmr spectroscopy and it shows that bope(78-261) comprises two three-helix bundles (alpha1alpha4alpha5 and alpha2alpha3alpha6). this fold is similar to that adopted by the ... | 2008 | 18052936 |
| fatal septicemia caused by chromobacterium violaceum in a child from colombia. | a 4-year old child living in colombia presented with a history of fever and severe abdominal pain for four days. the patient developed pneumonia, septic shock, multiple organ failure and died on the fifth day of hospitalization. chromobacterium violaceum was isolated from admission blood cultures and was resistant to ampicillin, cephalosporins, carbapenems and aminoglycosides. | 2007 | 18157408 |
| the violacein biosynthetic enzyme vioe shares a fold with lipoprotein transporter proteins. | vioe, an unusual enzyme with no characterized homologues, plays a key role in the biosynthesis of violacein, a purple pigment with antibacterial and cytotoxic properties. without bound cofactors or metals, vioe, from the bacterium chromobacterium violaceum, mediates a 1,2 shift of an indole ring and oxidative chemistry to generate prodeoxyviolacein, a precursor to violacein. our 1.21 a resolution structure of vioe shows that the enzyme shares a core fold previously described for lipoprotein tran ... | 2008 | 18171675 |
| n-acylhomoserine lactone regulates violacein production in chromobacterium violaceum type strain atcc 12472. | in tests, chromobacterium violaceum atcc 12472 produced several n-acyl-l-homoserine lactones (ahls). of these, n-(3-hydroxydecanoyl)-l-homoserine lactone was dominant, and controlled violacein production by quorum sensing. strain vir07, an ahl-deficient mutant, did not produce violacein. violacein production in vir07 was induced by adding long-chain ahls (c10-c16), but was inhibited by adding short-chain ahls (c4-c8). strain vir07 showed the response of violacein production when ahls diffused fr ... | 2008 | 18177311 |
| the chaperone ipgc copurifies with the virulence regulator mxie. | the expression of a subset of shigella flexneri virulence genes is dependent upon a cytoplasmic chaperone, ipgc, and an activator from the arac/xyls family, mxie. in this paper, we report that the chaperone forms a specific and stable heteromer with mxie. | 2008 | 18192384 |
| a rhodococcus qsda-encoded enzyme defines a novel class of large-spectrum quorum-quenching lactonases. | a gene involved in n-acyl homoserine lactone (n-ahsl) degradation was identified by screening a genomic library of rhodococcus erythropolis strain w2. this gene, named qsda (for quorum-sensing signal degradation), encodes an n-ahsl lactonase unrelated to the two previously characterized n-ahsl-degrading enzymes, i.e., the lactonase aiia and the amidohydrolase aiid. qsda is related to phosphotriesterases and constitutes the reference of a novel class of n-ahsl degradation enzymes. it confers the ... | 2008 | 18192419 |
| fatal septicaemia due to chromobacterium violaceum. | human infection caused by chromobacterium violaceum is rare but when it occurs, it is associated with a high mortality rate. this is a report of a young adult male who presented as a surgical emergency and succumbed soon after. the most common feature of this infection is sepsis, followed by cutaneous involvement and liver abscesses. chromobacterium infection as a differential in a case of sepsis is important for clinicians to suspect, especially in tropical countries. | 2007 | 18198747 |
| diversity and quorum-sensing signal production of proteobacteria associated with marine sponges. | marine sponges are hosts to diverse and dense bacterial communities and thus provide a potential environment for quorum sensing. quorum sensing, a key factor in cell-cell communication and bacterial colonization of higher animals, might be involved in the symbiotic interactions between bacteria and their sponge hosts. given that marine proteobacteria are known to produce n-acyl homoserine lactone (ahl) signal molecules, we tested the production of ahls by alpha- and gammaproteobacteria isolated ... | 2008 | 18211268 |
| structural basis for mannose recognition by a lectin from opportunistic bacteria burkholderia cenocepacia. | chronic colonization of the lungs by opportunist bacteria such as pseudomonas aeruginosa and members of the bcc (burkholderia cepacia complex) is the major cause of morbidity and mortality among cf (cystic fibrosis) patients. pa-iil (lecb gene), a soluble lectin from ps. aeruginosa, has been the subject of much interest because of its very strong affinity for fucose. orthologues have been identified in the opportunist bacteria ralstonia solanacearum, chromobacterium violaceum and burkholderia of ... | 2008 | 18215132 |
| residues near the amino terminus of rns are essential for positive autoregulation and dna binding. | most members of the arac/xyls family contain a conserved carboxy-terminal dna binding domain and a less conserved amino-terminal domain involved in binding small-molecule effectors and dimerization. however, there is no evidence that rns, a regulator of enterotoxigenic escherichia coli virulence genes, responds to an effector ligand, and in this study we found that the amino-terminal domain of rns does not form homodimers in vivo. exposure of rns to the chemical cross-linker glutaraldehyde revea ... | 2008 | 18223083 |
| control of acetic acid fermentation by quorum sensing via n-acylhomoserine lactones in gluconacetobacter intermedius. | a number of gram-negative bacteria regulate gene expression in a cell density-dependent manner by quorum sensing via n-acylhomoserine lactones (ahls). gluconacetobacter intermedius nci1051, a gram-negative acetic acid bacterium, produces three different ahls, n-decanoyl-l-homoserine lactone, n-dodecanoyl-l-homoserine lactone, and an n-dodecanoyl-l-homoserine lactone with a single unsaturated bond in its acyl chain, as determined by liquid chromatography-tandem mass spectrometry. two genes encodi ... | 2008 | 18245283 |
| higher infection of dengue virus serotype 2 in human monocytes of patients with g6pd deficiency. | the prevalence of glucose-6-phosphate dehydrogenase (g6pd) deficiency is high in asia. an ex vivo study was conducted to elucidate the association of g6pd deficiency and dengue virus (denv) infection when many asian countries are hyper-endemic. human monocytes from peripheral mononuclear cells collected from 12 g6pd-deficient patients and 24 age-matched controls were infected with one of two denv serotype 2 (denv-2) strains-the new guinea c strain (from a case of dengue fever) or the 16681 strai ... | 2008 | 18270558 |
| isolation and characterization of an autoinducer synthase from acinetobacter baumannii. | the opportunistic human pathogen acinetobacter baumannii strain m2 was found to produce distinct acyl-homoserine lactone (ahl) signals based on the use of an agrobacterium tumefaciens trag-lacz biosensor. an a. baumannii gene, designated abai, was cloned and directed ahl production in recombinant escherichia coli. the abai protein was similar to members of the luxi family of autoinducer synthases and was predicted to be the only autoinducer synthase encoded by a. baumannii. the primary ahl signa ... | 2008 | 18281398 |
| [successful treatment of a case with fatal sepsis caused by chromobacterium violaceum]. | | 2007 | 18282432 |
| determination of the cyclic depsipeptide fk228 in human and mouse plasma by liquid chromatography with mass-spectrometric detection. | an analytical method was developed and validated for the quantitative determination of the cyclic depsipeptide fk228 (romidepsin, formerly fr901228; nsc 630176), a histone deacetylase inhibitor, in human and mouse plasma. calibration curves were linear in the concentration range of 2-1000 ng/ml. sample pretreatment involved a liquid-liquid extraction of 0.1 ml aliquots of plasma with ethyl acetate. fk228 and the internal standard, harmine, were separated on a zorbax sb c18 column (75 mm x 2.1mm, ... | 2008 | 18342585 |
| diversity in antifungal activity of strains of chromobacterium violaceum from the brazilian amazon. | chromobacterium violaceum is a free-living gram-negative bacterium found in soil and aquatic habitats; abundantly present in the brazilian amazon, it is an important example of exploitable microbial diversity of the tropics. in this study, 24 strains from the brazilian amazon and atcc 12472(t) were investigated for biocontrol potential of seven fungi pathogenic to soybean [glycine max (l.) merril] seed. both cells and the supernatants of two brazilian strains, 07-1 and 27-1, together with atcc 1 ... | 2008 | 18347828 |
| crystal structure of escherichia coli mazg, the regulator of nutritional stress response. | mazg is a nucleoside triphosphate pyrophosphohydrolase that hydrolyzes all canonical nucleoside triphosphates. the mazg gene located downstream from the chromosomal mazef "addiction module," that mediated programmed cell death in escherichia coli. mazg activity is inhibited by the mazef complex both in vivo and in vitro. enzymatic activity of mazg in vivo affects the cellular level of guanosine 3',5'-bispyrophosphate (ppgpp), synthesized by rela under amino acid starvation. the reduction of ppgp ... | 2008 | 18353782 |
| cdna-aflp analysis of plant and pathogen genes expressed in grapevine infected with plasmopara viticola. | the oomycete plasmopara viticola (berk. and curt.) berl. and de toni causes downy mildew in grapevine (vitis vinifera l.). this pathogen is strictly biotrophic, thus completely dependent on living host cells for its survival. the molecular basis of compatibility and disease development in this system is poorly understood. we have carried out a large-scale cdna-aflp analysis to identify grapevine and p. viticola genes associated with the infection process. | 2008 | 18366764 |
| bacteria flora and heavy metals in cultivated oysters crassostrea iredalei of setiu wetland, east coast peninsular malaysia. | slipper oyster crassostrea iredalei is a species of good demand for its sweet flavor and white coloured flesh. the filter feeding nature predisposes oysters to accumulation of pathogenic and heavy metals in waters impacted by sewage pollutions and may thus render the oysters unfit for human consumption. a study was undertaken to investigate the presence of bacteria flora and heavy metal concentrations in cultivated oysters crassostrea iredalei at setiu wetland, terengganu, the only source of cul ... | 2008 | 18369732 |
| genome sequence of the streptomycin-producing microorganism streptomyces griseus ifo 13350. | we determined the complete genome sequence of streptomyces griseus ifo 13350, a soil bacterium producing an antituberculosis agent, streptomycin, which is the first aminoglycoside antibiotic, discovered more than 60 years ago. the linear chromosome consists of 8,545,929 base pairs (bp), with an average g+c content of 72.2%, predicting 7,138 open reading frames, six rrna operons (16s-23s-5s), and 66 trna genes. it contains extremely long terminal inverted repeats (tirs) of 132,910 bp each. the te ... | 2008 | 18375553 |
| gene expression of the arsenic resistance operon in chromobacterium violaceum atcc 12472. | chromobacterium violaceum atcc 12472 presents an arsrcb-type operon, which is involved in arsenic resistance. the regulating protein of this resistance system (arsr) does not have the small conserved site (elcvdcl) to link to the metalloid, as observed in escherichia coli, and is thus considered to be an atypical arsr protein, like that observed in acidithiobacillus ferrooxidans. in the present study, the gene expression profile of the ars operon under induction at different concentrations of ar ... | 2008 | 18388983 |
| rethinking proteasome evolution: two novel bacterial proteasomes. | the proteasome is a multisubunit structure that degrades proteins. protein degradation is an essential component of regulation because proteins can become misfolded, damaged, or unnecessary. proteasomes and their homologues vary greatly in complexity: from hslv (heat shock locus v), which is encoded by 1 gene in bacteria, to the eukaryotic 20s proteasome, which is encoded by more than 14 genes. despite this variation in complexity, all the proteasomes are composed of homologous subunits. we sear ... | 2008 | 18389302 |
| chromobacterium aquaticum sp. nov., isolated from spring water samples. | strain cc-seya-1t, a motile, gram-negative, non-violet-pigmented bacterium, was isolated on nutrient agar from spring-water samples collected from yang-ming mountain, taipei county, taiwan. 16s rrna gene sequence studies showed that the strain clustered with chromobacterium violaceum (96.8 % similarity) and chromobacterium subtsugae (96.5 % similarity), followed by aquitalea magnusonii (95.8 % similarity). the fatty acid profile was slightly different from those reported for c. violaceum, c. sub ... | 2008 | 18398186 |
| inactivation of [fe-s] metalloproteins mediates nitric oxide-dependent killing of burkholderia mallei. | much remains to be known about the mechanisms by which o(2)-dependent host defenses mediate broad antimicrobial activity. | 2008 | 18398486 |
| degradation of n-acyl homoserine lactone quorum sensing signal molecules by forest root-associated fungi. | a collection of mycorrhizal and nonmycorrhizal root-associated fungi coming from forest environments was screened for their ability to degrade n-acyl homoserine lactones (ahl) or to prevent ahl recognition by producing quorum sensing inhibitors (qsi). no production of qs-inhibitors or -activators was detected using the two biosensors chromobacterium violaceum cv026 and agrobacterium tumefaciens in the culture supernatant of these fungi. however, the ability to degrade c6- and 3o,c6-hsl was detec ... | 2008 | 18400006 |
| ppsy: a vector for the stable cloning and expression of streptomycete single gene phenotypes in escherichia coli. | ppsy is a 12kb cloning vector derived from the incw plasmid r388, which provides a rapid and easy way to stably clone phenotypes encoded in dna segments <10kb. in the present study three different genes were amplified by pcr, cloned into pgem-t easy and sub-cloned into the ecori site of ppsy. the first gene, vioa, is a fad-dependent l-tryptophan amino acid oxygenase from the high g+c gram-negative bacterium chromobacterium violaceum. vioa is involved in the synthesis of the indolocarbazole antit ... | 2008 | 18406459 |
| negative regulation of quorum-sensing systems in pseudomonas aeruginosa by atp-dependent lon protease. | lon protease, a member of the atp-dependent protease family, regulates numerous cellular systems by degrading specific substrates. here, we demonstrate that lon is involved in the regulation of quorum-sensing (qs) signaling systems in pseudomonas aeruginosa, an opportunistic human pathogen. the organism has two acyl-homoserine lactone (hsl)-mediated qs systems, lasr/lasi and rhlr/rhli. many reports have demonstrated that these two systems are regulated and interconnected by global regulators. we ... | 2008 | 18408026 |
| kinetics of thermal unfolding of phenylalanine hydroxylase variants containing different metal cofactors (feii, coii, and znii) and their isokinetic relationship. | the kinetics of thermal unfolding of apo- and holo-chromobacterium violaceum phenylalanine hydroxylase (cpah) was investigated using circular dichroism (cd) over the temperature range 44-76 degrees c. in addition to the native cofactor (feii), the unfolding kinetics of holo-cpah was characterized using znii and coii as cofactors. kinetic profiles for apo- and holo-cpah showed a single-phase exponential rise in the cd signal at lambda=222 nm and a first-order dependence on protein concentration. ... | 2008 | 18433092 |
| chromobacterium violaceum cellulitis and sepsis following cutaneous marine trauma. | chromobacterium violaceum is a gram-negative bacillary organism that characteristically produces the purple pigment violacein. documented as the cause of clinically relevant human infections in only 35 cases in the united states, c violaceum is particularly seen in patients with a history of cutaneous injury or trauma. we report the case of an 18-year-old woman who was struck by a propeller in a boating accident and sustained multiple deep lacerations of her right lower extremity. shortly after ... | 2008 | 18441852 |
| cyanogenic pseudomonads influence multitrophic interactions in the rhizosphere. | in the rhizosphere, plant roots cope with both pathogenic and beneficial bacterial interactions. the exometabolite production in certain bacterial species may regulate root growth and other root-microbe interactions in the rhizosphere. here, we elucidated the role of cyanide production in pseudomonad virulence affecting plant root growth and other rhizospheric processes. exposure of arabidopsis thaliana col-0 seedlings to both direct (with kcn) and indirect forms of cyanide from different pseudo ... | 2008 | 18446201 |
| neonatal septicaemia in calabar, nigeria. | a three-year survey of neonatal septicaemia (363 bacteriologically proven cases) in the university of calabar teaching hospital, calabar, has demonstrated that the dominant blood isolate was staphylococcus aureus (53%) followed by unclassified coliforms (20%), an unexpected chromobacterium violaceum (5%). the incidence of neonatal septicaemia was 54.9 per 1000 live births for inborn infants. the predominant organisms were largely susceptible to gentamicin, ceftriazone and cefuroxime with a morta ... | 2008 | 18453516 |