| outbreak of otitis media caused by burkholderia gladioli infection in immunocompromised mice. | an athymic nude mouse with severe head tilt due to otitis media was identified. within weeks of identification of this first case, immune-deficient mice of various genotypes from the same facility were similarly affected, and cases from other facilities were found within two months. culture of ear exudate specimens from affected mice yielded bacteria that were initially identified as burkholderia cepacia, a plant pathogen considered an important opportunistic pathogen in persons with cystic fibr ... | 2004 | 15027624 |
| biosynthesis of poly(3-hydroxybutyrate- co-3-hydroxyalkanoates) by metabolically engineered escherichia coli strains. | biosynthesis of polyhydroxyalkanoates (phas) consisting of 3-hydroxy-alkanoates (3has) of 4 to 10 carbon atoms was examined in metabolically engineered escherichia coli strains. when the fada and/or fadb mutant e. coli strains harboring the plasmid containing the pseudomonas sp. 61-3 phac2 gene and the ralstonia eutropha phaab genes were cultured in luria-bertani (lb) medium supplemented with 2 g/l of sodium decanoate, all the recombinant e. coli strains synthesized phas consisting of c4, c6, c8 ... | 2004 | 15054261 |
| biosynthesis of r-3-hydroxyalkanoic acids by metabolically engineered escherichia coli. | an efficient system for the production of (r)-hydroxyalkanoic acids (rhas) was developed in natural polyhydroxyalkanoate (pha)-producing bacteria and recombinant escherichia coli. acidic alcoholysis of purified pha and in vivo depolymerization of pha accumulated in the cells allowed the production of rhas. in recombinant e. coli, rha production was achieved by removing coa from (r)-3-hydroxyacyl-coa and by in vivo depolymerization of pha. when the recombinant e. coli harboring the ralstonia eutr ... | 2004 | 15054264 |
| characterization of the cis-acting regulatory element controlling hrpb-mediated activation of the type iii secretion system and effector genes in ralstonia solanacearum. | the ability of ralstonia solanacearum to cause disease on plants depends on its type iii secretion system (ttss) encoded by hrp genes. the expression of hrp genes and known ttss substrates is coordinately regulated by hrpb, a member of the arac family of transcriptional regulators. two hrpb-regulated promoters (hrpy and popabc) were characterized by deletion analysis, and the hrpb-dependent activation of these promoters was found to be conferred by a 25-nucleotide dna element, the hrp(ii) box (t ... | 2004 | 15060033 |
| unraveling the function of the rhodospirillum rubrum activator of polyhydroxybutyrate (phb) degradation: the activator is a phb-granule-bound protein (phasin). | efficient hydrolysis of native poly(3-hydroxybutyrate) (nphb) granules in vitro by soluble phb depolymerase of rhodospirillum rubrum requires pretreatment of nphb with an activator compound present in r. rubrum cells (j. m. merrick and m. doudoroff, j. bacteriol. 88:60-71, 1964). edman sequencing of the purified activator (17.4 kda; matrix-assisted laser desorption ionization-time of flight mass spectrometry) revealed identity to a hypothetical protein deduced from a partially sequenced r. rubru ... | 2004 | 15060050 |
| identification of the bacterial community of maple sap by using amplified ribosomal dna (rdna) restriction analysis and rdna sequencing. | the bacterial community of maple sap was characterized by analysis of samples obtained at the taphole of maple trees for the 2001 and 2002 seasons. among the 190 bacterial isolates, 32 groups were formed according to the similarity of the banding patterns obtained by amplified ribosomal dna restriction analysis (ardra). a subset of representative isolates for each ardra group was identified by 16s rrna gene fragment sequencing. results showed a wide variety of organisms, with 22 different genera ... | 2004 | 15066796 |
| bacteriophages and insertion sequences of chromobacterium violaceum atcc 12472. | a fluid genome is a great advantage to prokaryotes, enabling quick adaptation to various types of ecological niches and to diverse environmental selective pressures. a substantial portion of these sudden changes is mediated by lateral gene transfer (lgt), through genetic recombination mechanisms, such as transformation, conjugation and transduction. the recent sequencing of several organisms has offered a new approach to the study of lgt, using comparison and analysis of nucleotide sequences dis ... | 2004 | 15100989 |
| dna repair in chromobacterium violaceum. | chromobacterium violaceum is a gram-negative beta-proteobacterium that inhabits a variety of ecosystems in tropical and subtropical regions, including the water and banks of the negro river in the brazilian amazon. this bacterium has been the subject of extensive study over the last three decades, due to its biotechnological properties, including the characteristic violacein pigment, which has antimicrobial and anti-tumoral activities. c. violaceum promotes the solubilization of gold in a mercur ... | 2004 | 15100997 |
| a new ralstonia solanacearum high-affinity mannose-binding lectin rs-iil structurally resembling the pseudomonas aeruginosa fucose-specific lectin pa-iil. | the plant pathogen ralstonia solanacearum produces two lectins, each with different affinity to fucose. we described previously the properties and sequence of the first lectin, rsl (subunit m(r) 9.9 kda), which is related to fungal lectins (sudakevitz, d., imberty, a., and gilboa-garber, n., 2002, j biochem 132: 353-358). the present communication reports the discovery of the second one, rs-iil (subunit m(r) 11.6 kda), a tetrameric lectin, with high sequence similarity to the fucose-binding lect ... | 2004 | 15101976 |
| crystal structure of the oxidized form of the periplasmic mercury-binding protein merp from ralstonia metallidurans ch34. | in ralstonia metallidurans ch34, the gene merp encodes for a periplasmic mercury-binding protein which is capable of binding one mercury atom. the metal-binding site of merp consists of the highly conserved sequence gmtcxxc found in the family that includes metallochaperones and metal-transporting atpases. we purified merp from r.metallidurans ch34 and solved its crystal structure under the oxidized form at 2.0a resolution. superposition with structures of other metal-binding proteins shows that ... | 2004 | 15123428 |
| [dynamics of activity of the key enzymes of polyhydroxyalkanoate metabolism in ralstonia eutropha]. | the dynamics of accumulation of polyhydroxybutyrate (phb) and the activities of the key enzymes of phb metabolism (beta-ketothiolase, acetoacetyl-coa reductase, pha synthase, d-hydroxybutyrate dehydrogenase, and pha depolymerase) in the hydrogen bacterium ralstonia eutropha b5786 were studied under various conditions of carbon nutrition and substrate availability. the highest activities of beta-ketothiolase, acetoacetyl-coa reductase, and pha synthase were recorded at the stage of acceleration o ... | 2004 | 15125198 |
| toluene 3-monooxygenase of ralstonia pickettii pko1 is a para-hydroxylating enzyme. | oxygenases are promising biocatalysts for performing selective hydroxylations not accessible by chemical methods. whereas toluene 4-monooxygenase (t4mo) of pseudomonas mendocina kr1 hydroxylates monosubstituted benzenes at the para position and toluene ortho-monooxygenase (tom) of burkholderia cepacia g4 hydroxylates at the ortho position, toluene 3-monooxygenase (t3mo) of ralstonia pickettii pko1 was reported previously to hydroxylate toluene at the meta position, producing primarily m-cresol ( ... | 2004 | 15126473 |
| enzymatic surface-initiated polymerization: a novel approach for the in situ solid-phase synthesis of biocompatible polymer poly(3-hydroxybutyrate). | a novel system for surface-initiated enzymatic polymerization of a film of polyhydroxyalkanoate (pha) on solid surfaces has been developed and characterized. phas are aliphatic polyesters produced by a variety of microorganisms as a reserve of carbon and energy, and their properties range from elastomers to thermoplastics, depending on their monomeric composition. the pha synthase from ralstonia eutropha h16 was expressed as a poly-histidine fusion in escherichia coli and immobilized onto severa ... | 2004 | 15132678 |
| modal difference in comonomer-unit compositional distributions of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)s biosynthesized by two strains, ralstonia eutropha and alcaligenes latus. | | 2004 | 15132709 |
| the soluble [nife]-hydrogenase from ralstonia eutropha contains four cyanides in its active site, one of which is responsible for the insensitivity towards oxygen. | infrared spectra of (15)n-enriched preparations of the soluble cytoplasmic nad(+)-reducing [nife]-hydrogenase from ralstonia eutropha are presented. these spectra, together with chemical analyses, show that the ni-fe active site contains four cyanide groups and one carbon monoxide molecule. it is proposed that the active site is a (rs)(2)(cn)ni(micro-rs)(2)fe(cn)(3)(co) centre (r=cys) and that h(2) activation solely takes place on nickel. one of the two fmn groups (fmn-a) in the enzyme can be re ... | 2004 | 15164270 |
| characterization of the merd protein from ralstonia metallidurans ch34: a possible role in bacterial mercury resistance by switching off the induction of the mer operon. | merd and merr from tn4378 found in ralstonia metallidurans ch34 were purified to homogeneity after overexpression in escherichia coli. using electrophoretic mobility shift assays and footprinting experiments, we found that merd cannot bind to dna. however, in vitro merd can form a ternary complex in association with merop and merr. the presence of merd in this complex was demonstrated by western analysis with antibodies to merd. to our knowledge, this is the first description of such a ternary c ... | 2004 | 15165248 |
| adaptive responses to static conditions in nutrient-rich cultures of luminous ralstonia eutropha. | the lux-gene fused ralstonia eutropha, when adapting to static conditions, causes stratification of air-exposed and nutrient-rich cultures at above 0.15 mg biomass ml(-1). the o2 respiring biofilm (luminous neuston) phase, along with the dark sub-neustonic suspension phase, develops within 5-60 min. the instability of the biphasic static culture was identified as a reason for occasionally observable oscillatory bioluminescence. | 2004 | 15168854 |
| roles of poly(3-hydroxybutyrate) depolymerase and 3hb-oligomer hydrolase in bacterial phb metabolism. | many poly-3-hydroxybutyrate (phb)-degrading enzymes have been studied. but biological roles of 3hb-oligomer hydrolases (3hbohs) and how phb depolymerases (phbdps) and 3hbohs cooperate in phb metabolism are not fully elucidated. in this study, several phbdps and 3hbohs from three types of bacteria were purified, and their substrate specificity, kinetic properties, and degradation products were investigated. from the results, phbdp and 3hboh seemed to play a role in phb metabolism in three types o ... | 2004 | 15170237 |
| effects of quaternary-ammonium-based formulations on bacterial community dynamics and antimicrobial susceptibility. | quaternary ammonium compounds (qacs) are widely used as adjuncts to hygiene in domestic cleaning products. current concern that the increased use of such biocides in consumer products might contribute to the emergence of antibiotic resistance has led us to examine the effects of a qac-containing domestic cleaning fluid on the population dynamics and antimicrobial susceptibility of domestic sink drain biofilm communities. qac susceptibilities of numerically dominant, culturable drain bacteria (15 ... | 2004 | 15184143 |
| genetic organization of the catabolic plasmid pjp4 from ralstonia eutropha jmp134 (pjp4) reveals mechanisms of adaptation to chloroaromatic pollutants and evolution of specialized chloroaromatic degradation pathways. | ralstonia eutropha jmp134 (pjp4) is a useful model for the study of bacterial degradation of substituted aromatic pollutants. several key degrading capabilities, encoded by tfd genes, are located in the 88 kb, self-transmissible, incp-1 beta plasmid pjp4. the complete sequence of the 87,688 nucleotides of pjp4, encoding 83 open reading frames (orfs), is reported. most of the coding sequence corresponds to a well-conserved incp-1 beta backbone and the previously reported tfd genes. in addition, w ... | 2004 | 15186344 |
| swimming motility, a virulence trait of ralstonia solanacearum, is regulated by flhdc and the plant host environment. | swimming motility allows the bacterial wilt pathogen ralstonia solanacearum to efficiently invade and colonize host plants. however, the bacteria are essentially nonmotile once inside plant xylem vessels. to determine how and when motility genes are expressed, we cloned and mutated flhdc, which encodes a major regulator of flagellar biosynthesis and bacterial motility. an flhdc mutant was nonmotile and less virulent than its wild-type parent on both tomato and arabidopsis; on arabidopsis, the fl ... | 2004 | 15195951 |
| flagellin is not a major defense elicitor in ralstonia solanacearum cells or extracts applied to arabidopsis thaliana. | the phytopathogenic bacterium ralstonia solanacearum requires motility for full virulence, and its flagellin is a candidate pathogen-associated molecular pattern that may elicit plant defenses. boiled extracts from r. solanacearum contained a strong elicitor of defense-associated responses. however, r. solanacearum flagellin is not this elicitor, because extracts from wild-type bacteria and flic or flhdc mutants defective in flagellin production all elicited similar plant responses. equally impo ... | 2004 | 15195952 |
| transcription level of granule-associated phap and phar genes and granular morphogenesis of poly-beta-hydroxyalkanoate granules in ralstonia eutropha. | the transcription levels of the granule-associated phap and phar genes in ralstonia eutropha were regulated through the transformation of the phbc genes from r. eutropha and alcaligenes latus into the poly-beta-hydroxybutyrate synthase-negative mutant. the granular morphogenesis of short chain length, poly-beta-hydroxyalkanoate (scl-pha) was closely associated with the mrna transcription levels of the phap and phar genes, especially with the ratio of phap/phar genes. the phasin protein encoded b ... | 2004 | 15200169 |
| altering the substrate specificity of polyhydroxyalkanoate synthase 1 derived from pseudomonas putida gpo1 by localized semirandom mutagenesis. | the substrate specificity of polyhydroxyalkanoate (pha) synthase 1 (phac1(pp), class ii) from pseudomonas putida gpo1 (formerly known as pseudomonas oleovorans gpo1) was successfully altered by localized semirandom mutagenesis. the enzyme evolution system introduces multiple point mutations, designed on the basis of the conserved regions of the pha synthase family, by using pcr-based gene fragmentation with degenerate primers and a reassembly pcr. according to the opaqueness of the colony, indic ... | 2004 | 15205419 |
| phylogeny based on 16s rdna and nifh sequences of ralstonia taiwanensis strains isolated from nitrogen-fixing nodules of mimosa pudica, in india. | bacterial symbionts present in the indeterminate-type nitrogen (n)-fixing nodules of mimosa pudica grown in north and south india showed maximum similarity to ralstonia taiwanensis on the basis of carbon-source utilization patterns and 16s rdna sequence. isolates from the nodules of m. pudica from north india and south india showed identical ardra (amplified ribosomal dna restriction analysis) patterns with sau3ai and rsai, but alui revealed dimorphy between the north indian and south indian iso ... | 2004 | 15213739 |
| proteome analysis of gentisate-induced response in pseudomonas alcaligenes ncib 9867. | pseudomonas alcaligenes ncib 9867 (p25x wild-type) is capable of degrading aromatic hydrocarbons via the gentisate pathway. biochemical characterization of p25x mutants indicated that it has isofunctional enzymes for the mono- and dioxygenase-catalyzed reactions. one set of the enzymes is constitutive whereas the other is strictly inducible. to date, only the gene encoding the constitutively-expressed gentisate dioxygenase had been cloned and characterized. a mutant strain of p25x, designated g5 ... | 2004 | 15221764 |
| inventory and functional analysis of the large hrp regulon in ralstonia solanacearum: identification of novel effector proteins translocated to plant host cells through the type iii secretion system. | the ability of ralstonia solanacearum strain gmi1000 to cause disease on a wide range of host plants (including most solanaceae and arabidopsis thaliana) depends on genes activated by the regulatory gene hrpb. hrpb controls the expression of the type iii secretion system (ttss) and pathogenicity effectors transiting through this pathway. in order to establish the complete repertoire of ttss-dependent effectors belonging to the hrp regulon and to start their functional analysis, we developed a ra ... | 2004 | 15225308 |
| chlorophenol removal from soil suspensions: effects of a specialised microbial inoculum and a degradable analogue. | two soils of different contamination history were tested in slurry for their self-remediability towards mono-, di- and trisubstituted chlorophenols. the landfill soil showed poor ability in removing the compounds. instead, the soil from the golf course, treated for many years with a 2,4,6-trichlorophenol derivative (prochloraz), remediated different concentrations of the same 2,4,6tcp, 2,4-dichlorophenol and monochlorophenol isomers, singly and in mixtures, at varying degradation rates. ralstoni ... | 2004 | 15228073 |
| quinohemoprotein alcohol dehydrogenases: structure, function, and physiology. | quino(hemo)protein alcohol dehydrogenases (adh) that have pyrroloquinoline quinone (pqq) as the prosthetic group are classified into 3 groups, types i, ii, and iii. type i adh is a simple quinoprotein having pqq as the only prosthetic group, while type ii and type iii adhs are quinohemoprotein having heme c as well as pqq in the catalytic polypeptide. type ii adh is a soluble periplasmic enzyme and is widely distributed in proteobacteria such as pseudomonas, ralstonia, comamonas, etc. in contras ... | 2004 | 15234265 |
| oxidation of benzene to phenol, catechol, and 1,2,3-trihydroxybenzene by toluene 4-monooxygenase of pseudomonas mendocina kr1 and toluene 3-monooxygenase of ralstonia pickettii pko1. | aromatic hydroxylations are important bacterial metabolic processes but are difficult to perform using traditional chemical synthesis, so to use a biological catalyst to convert the priority pollutant benzene into industrially relevant intermediates, benzene oxidation was investigated. it was discovered that toluene 4-monooxygenase (t4mo) of pseudomonas mendocina kr1, toluene 3-monooxygenase (t3mo) of ralstonia pickettii pko1, and toluene ortho-monooxygenase (tom) of burkholderia cepacia g4 conv ... | 2004 | 15240250 |
| abundance of dioxygenase genes similar to ralstonia sp. strain u2 nagac is correlated with naphthalene concentrations in coal tar-contaminated freshwater sediments. | we designed a real-time pcr assay able to recognize dioxygenase large-subunit gene sequences with more than 90% similarity to the ralstonia sp. strain u2 nagac gene (nagac-like gene sequences) in order to study the importance of organisms carrying these genes in the biodegradation of naphthalene. sequencing of pcr products indicated that this real-time pcr assay was specific and able to detect a variety of nagac-like gene sequences. one to 100 ng of contaminated-sediment total dna in 25-microl r ... | 2004 | 15240274 |
| detection of genes involved in biodegradation and biotransformation in microbial communities by using 50-mer oligonucleotide microarrays. | to effectively monitor biodegrading populations, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the 2,402 known genes and pathways involved in biodegradation and metal resistance. this array contained 1,662 unique and group-specific probes with <85% similarity to their nontarget sequences. based on artificial probes, our results showed that under hybridization conditions of 50 degrees c and 50% formamide, the 50-mer microarray hybridization can differentia ... | 2004 | 15240314 |
| effective enhancement of short-chain-length-medium-chain-length polyhydroxyalkanoate copolymer production by coexpression of genetically engineered 3-ketoacyl-acyl-carrier-protein synthase iii (fabh) and polyhydroxyalkanoate synthesis genes. | polyhydroxyalkanoates (phas) are biodegradable polyesters that have a wide variety of physical properties dependent on the lengths of the pendant groups of the monomer units in the polymer. phas composed of mostly short-chain-length (scl) monomers are often stiff and brittle, whereas phas composed of mostly medium-chain-length (mcl) monomers are elastomeric in nature. scl-mcl pha copolymers can have properties between the two states, dependent on the ratio of scl and mcl monomers in the copolyme ... | 2004 | 15244465 |
| identification of the anabaena sp. strain pcc7120 cyanophycin synthetase as suitable enzyme for production of cyanophycin in gram-negative bacteria like pseudomonas putida and ralstonia eutropha. | the cyanophycin synthetase gene cpha1 encoding the major cyanophycin synthetase (cpha) of anabaena sp. strain pcc7120 was expressed in escherichia coli conferring so far the highest specific cpha activity to e. coli (6.7 nmol arginine per min and mg protein). cpha1 and cpha genes of synechocystis sp. strains pcc6803 and pcc6308 and synechococcus strain ma19 were also expressed in wild types and polyhydroxyalkanoate-negative (pha) mutants of pseudomonas putida and ralstonia eutropha. recombinant ... | 2004 | 15244482 |
| mutagenesis study on amino acids around the molybdenum centre of the periplasmic nitrate reductase from ralstonia eutropha. | molybdenum enzymes containing the pterin cofactor are a diverse group of enzymes that catalyse in general oxygen atom transfer reactions. aiming at studying the amino acid residues, which are important for the enzymatic specificity, we used nitrate reductase from ralstonia eutropha (r.e.nap) as a model system for mutational studies at the active site. we mutated amino acids at the mo active site (cys181 and arg421) as well as amino acids in the funnel leading to it (met182, asp196, glu197, and t ... | 2004 | 15249219 |
| a hydrogen-evolving enzyme is present in frankia sp. r43. | the ability to evolve hydrogen using methyl viologen as an electron donor was assayed in the nitrogen-fixing actinomycetes frankia sp. r43 and frankia sp. kb5. to further examine the nature of hydrogen-evolving enzymes that may be present in these organisms immunological studies were performed. under anaerobic conditions (both nitrogen-limiting and nitrogen-containing) frankia sp. r43 but not frankia sp. kb5 evolved hydrogen,which was not linked to nad-reducing activity. immunological analysis o ... | 2004 | 15251202 |
| the complex structure of polyhydroxybutyrate (phb) granules: four orthologous and paralogous phasins occur in ralstonia eutropha. | analysis of the genome sequence of the polyhydroxyalkanoate- (pha) accumulating bacterium ralstonia eutropha strain h16 revealed three homologues (phap2, phap3 and phap4) of the phasin protein phap1. phap1 is known to constitute the major component of the layer at the surface of poly(3-hydroxybutyrate), poly(3hb), granules. phap2, phap3 and phap4 exhibited 42, 49 and 45 % identity or 61, 62 and 63 % similarity to phap1, respectively. the calculated molecular masses of phap1, phap2, phap3 and pha ... | 2004 | 15256572 |
| the structure of the o-specific polysaccharide from ralstonia pickettii. | the following structure of the ralstonia pickettii have been determined using nmr and chemical methods: -->4)-alpha-d-rha-(1-->4)-alpha-l-galnaca-(1-->3)-beta-d-bacnac-(1-->. | 2004 | 15261599 |
| a novel p-nitrophenol degradation gene cluster from a gram-positive bacterium, rhodococcus opacus sao101. | p-nitrophenol (4-np) is recognized as an environmental contaminant; it is used primarily for manufacturing medicines and pesticides. to date, several 4-np-degrading bacteria have been isolated; however, the genetic information remains very limited. in this study, a novel 4-np degradation gene cluster from a gram-positive bacterium, rhodococcus opacus sao101, was identified and characterized. the deduced amino acid sequences of npcb, npca, and npcc showed identity with phenol 2-hydroxylase compon ... | 2004 | 15262926 |
| the v antigen of pseudomonas aeruginosa is required for assembly of the functional popb/popd translocation pore in host cell membranes. | pseudomonas aeruginosa efficiently intoxicates eukaryotic cells through the activity of the type iii secretion-translocation system (ttss). gene deletions within the translocation operon pcrgvh-popbd abolish pore-forming activity of p. aeruginosa strains with macrophages and ttss-dependent hemolysis. here we investigated the requirements for pcrv, popb, and popd in pore formation by analyzing specific mutants using red blood cells (rbcs) and fibroblasts expressing green fluorescent protein fused ... | 2004 | 15271936 |
| [study of ralstonia eutropha culture producing polyhydroxyalkanoates on products of coal processing]. | kinetic indices of growth, polyhydroxyalkanoate (pha) accumulation, and gas exchange have been studied in a culture of the carbon monoxide-resistant hydrogen strain ralstonia eutropha b-5786 grown on a gaseous substrate (gs) obtained by lignite gasification. the gs was shown to be suitable for pha production. to increase the degree of gs consumption, various modes of gas supply to the culture were tested. based on the results, an algorithm was developed for calculating and controlling gas-exchan ... | 2004 | 15283331 |
| lessons learned from the genome analysis of ralstonia solanacearum. | ralstonia solanacearum is a devastating plant pathogen with a global distribution and an unusually wide host range. this bacterium can also be free-living as a saprophyte in water or in the soil in the absence of host plants. the availability of the complete genome sequence from strain gmi1000 provided the basis for an integrative analysis of the molecular traits determining the adaptation of the bacterium to various environmental niches and pathogenicity toward plants. this review summarizes cu ... | 2004 | 15283662 |
| type iii secretion system effector proteins: double agents in bacterial disease and plant defense. | many phytopathogenic bacteria inject virulence effector proteins into plant cells via a hrp type iii secretion system (ttss). without the ttss, these pathogens cannot defeat basal defenses, grow in plants, produce disease lesions in hosts, or elicit the hypersensitive response (hr) in nonhosts. pathogen genome projects employing bioinformatic methods to identify ttss hrp regulon promoters and ttss pathway targeting signals suggest that phytopathogenic pseudomonas, xanthomonas, and ralstonia spp. ... | 2004 | 15283671 |
| degradation of estradiol and ethinyl estradiol by activated sludge and by a defined mixed culture. | the aerobic degradation of the natural hormone 17-beta-estradiol (e2) and the synthetic hormone 17-alpha-ethinyl estradiol (ee2) was investigated in batch experiments with activated sludge from a conventional and a membrane sewage treatment plant. e2 was converted to estrone (e1), the well known metabolite, and further completely transformed within 3 days. the turnover rates of e2 did not differ greatly between conventional and membrane activated sludge. ee2 was persistent in both sludges. by se ... | 2005 | 15290133 |
| amino acid-type edited nmr experiments for methyl-methyl distance measurement in 13c-labeled proteins. | new nmr experiments are presented for the measurement of methyl-methyl distances in (13)c-labeled proteins from a series of amino acid-type separated 2d or 3d noesy spectra. hadamard amino acid-type encoding of the proximal methyl groups provides the high spectral resolution required for unambiguous methyl-methyl noe assignment, which is particularly important for fast global fold determination of proteins. the experiments can be applied to a wide range of protein systems, as exemplified for two ... | 2004 | 15291562 |
| failure of ceftriaxone in an intravenous drug user with invasive infection due to ralstonia pickettii. | we report a case of septic arthritis due to ralstonia pickettii in an intravenous drug user with unfavorable clinical course under antibiotic therapy with ceftriaxone despite in vitro susceptibility to the drug. the treatment failure may have been due to a discrepancy between in vitro and in vivo susceptibility of r. pickettii, or to resistance development mediated by a recently described inducible beta-lactamase. | 2004 | 15293083 |
| polyhydroxyalkanoate (pha) accumulation in sulfate-reducing bacteria and identification of a class iii pha synthase (phaec) in desulfococcus multivorans. | seven strains of sulfate-reducing bacteria (srb) were tested for the accumulation of polyhydroxyalkanoates (phas). during growth with benzoate desulfonema magnum accumulated large amounts of poly(3-hydroxybutyrate) [poly(3hb)]. desulfosarcina variabilis (during growth with benzoate), desulfobotulus sapovorans (during growth with caproate), and desulfobacterium autotrophicum (during growth with caproate) accumulated poly(3hb) that accounted for 20 to 43% of cell dry matter. desulfobotulus sapovor ... | 2004 | 15294771 |
| metabolic carbon fluxes and biosynthesis of polyhydroxyalkanoates in ralstonia eutropha on short chain fatty acids. | short chain fatty acids such as acetic, propionic, and butyric acids can be synthesized into polyhydroxyalkanoates (phas) by ralstonia eutropha. metabolic carbon fluxes of the acids in living cells have significant effect on the yield, composition, and thermomechanical properties of pha bioplastics. based on the general knowledge of central metabolism pathways and the unusual metabolic pathways in r. eutropha, a metabolic network of 41 bioreactions is constructed to analyze the carbon fluxes on ... | 2004 | 15296425 |
| distribution and sequence analysis of a family of type ill-dependent effectors correlate with the phylogeny of ralstonia solanacearum strains. | in ralstonia solanacearum, we previously have reported on the characterization of popp1 and popp2 genes. these genes encode type iii-dependent pathogenicity effectors related to the large family of avrrxv/yopj cysteine proteases that are shared among pathogens of plants and animals. in this study, we identify a third gene, named popp3, that is inactivated in the genome sequence of strain gmi1000 by insertion of a copy of the insertion sequence isrso13. the three popp genes are localized on two l ... | 2004 | 15305614 |
| beta-lactamase production and antimicrobial susceptibility of subgingival bacteria from refractory periodontitis. | this study assessed the extent of beta-lactamase-producing bacteria in subgingival plaque samples obtained from 25 patients with refractory marginal periodontitis in the usa. beta-lactamase-positive isolates were characterized using commercial diagnostic kits and partial sequencing of the 16s rrna gene. the susceptibilities to different antimicrobial agents were tested and, in addition, the isolates were screened for the presence of extended spectrum beta-lactamases (esbls). beta-lactamase-produ ... | 2004 | 15327642 |
| photosynthetically oxygenated salicylate biodegradation in a continuous stirred tank photobioreactor. | a consortium consisting of a chlorella sorokiniana strain and a ralstonia basilensis strain was able to carry out sodium salicylate biodegradation in a continuous stirred tank reactor (cstr) using exclusively photosynthetic oxygenation. salicylate biodegradation depended on algal activity, which itself was a function of microalgal concentration, light intensity, and temperature. biomass recirculation improved the photobioreactor performance by up to 44% but the results showed the existence of an ... | 2004 | 15329938 |
| molecular identification and characterization of an alginate-binding protein on the cell surface of sphingomonas sp. a1. | cells of sphingomonas sp. a1 (strain a1) directly incorporate a macromolecule, alginate, into cytoplasm through a biosystem, or "super-channel," consisting of a pit on the cell surface, alginate-binding proteins in periplasm, and an abc transporter in the inner membrane. the pit functions as a concentrator for extracellular alginate. through differential display analysis, a protein (p8) with a molecular mass of 20kda and a pi of 7.4 was found to be inducibly expressed in the outer membrane of al ... | 2004 | 15336522 |
| escherichia coli hmp, an "oxygen-binding flavohaemoprotein", produces superoxide anion and self-destructs. | escherichia coli hmp is a homologue of ralstonia eutropha fhp, the first reported bacterial flavohaemoglobin, and functions in no detoxification. photolysis of co-ligated hmp in the presence of oxygen gave a photodissociable oxy species with k(on) 2.82x10(7) m(-1) s(-1) and k(off) 4.49x10(3) s(-1). the dissociation constant of the primary o(2) compound was 160 microm (25 degrees c, ph 7.0). in order to detect superoxide formation, ferric horseradish peroxidase was used. hmp formed the oxy compou ... | 2004 | 15340787 |
| the role of the active site-coordinating cysteine residues in the maturation of the h2-sensing [nife] hydrogenase from ralstonia eutropha h16. | the h(2)-splitting active site of [nife] hydrogenases is tightly bound to the protein matrix via four conserved cysteine residues. in this study, the nickel-binding cysteine residues of hoxc, the large subunit of the h(2)-sensing regulatory hydrogenase (rh) from ralstonia eutropha, were replaced by serine. all four mutant proteins, c60s, c63s, c479s, and c482s, were inactive both in h(2) sensing and h(2) oxidation and did not adopt the native oligomeric structure of the rh. nickel was bound only ... | 2004 | 15340794 |
| identification of a regulatory pathway that controls the heavy-metal resistance system czc via promoter czcnp in ralstonia metallidurans. | the czccba cation-proton-antiporter is the most complicated and efficient heavy-metal resistance system known today and is essential for survival of ralstonia metallidurans at high cobalt, zinc, or cadmium concentrations. expression of czc is tightly controlled by the complex interaction of several regulators. double- and multiple-deletion studies demonstrated that four regulators encoded downstream of the czccba operon, czcd, czcs, czcr and the newly identified czce, are involved in, but not es ... | 2004 | 15340798 |
| ralstonia solanacearum genes induced during growth in tomato: an inside view of bacterial wilt. | the phytopathogen ralstonia solanacearum has over 5000 genes, many of which probably facilitate bacterial wilt disease development. using in vivo expression technology (ivet), we screened a library of 133 200 r. solanacearum strain k60 promoter fusions and isolated approximately 900 fusions expressed during bacterial growth in tomato plants. sequence analysis of 307 fusions revealed 153 unique in planta-expressed (ipx) genes. these genes included seven previously identified virulence genes (pehr ... | 2004 | 15341645 |
| the auxiliary protein hypx provides oxygen tolerance to the soluble [nife]-hydrogenase of ralstonia eutropha h16 by way of a cyanide ligand to nickel. | the hypx gene of the facultative lithoautotrophic bacterium ralstonia eutropha is part of a cassette of accessory genes (the hyp cluster) required for the proper assembly of the active site of the [nife]-hydrogenases in the bacterium. a deletion of the hypx gene led to a severe growth retardation under lithoautotrophic conditions with 5 or 15% oxygen, when the growth was dependent on the activity of the soluble nad+ -reducing hydrogenase. the enzymatic and infrared spectral properties of the sol ... | 2004 | 15342627 |
| localization and characterization of two novel genes encoding stereospecific dioxygenases catalyzing 2(2,4-dichlorophenoxy)propionate cleavage in delftia acidovorans mc1. | two novel genes, rdpa and sdpa, encoding the enantiospecific alpha-ketoglutarate dependent dioxygenases catalyzing r,s-dichlorprop cleavage in delftia acidovorans mc1 were identified. significant similarities to other known genes were not detected, but their deduced amino acid sequences were similar to those of other alpha-ketoglutarate dioxygenases. rdpa showed 35% identity with taud of pseudomonas aeruginosa, and sdpa showed 37% identity with tfda of ralstonia eutropha jmp134. the functionally ... | 2004 | 15345421 |
| increasing the carbon flux toward synthesis of short-chain-length--medium-chain-length polyhydroxyalkanoate in the peroxisome of saccharomyces cerevisiae through modification of the beta-oxidation cycle. | short-chain-length-medium-chain-length polyhydroxyalkanoates were synthesized in saccharomyces cerevisiae from intermediates of the beta-oxidation cycle by expressing the polyhydroxyalkanoate synthases from aeromonas caviae and ralstonia eutropha in the peroxisomes. the quantity of polymer produced was increased by using a mutant of the beta-oxidation-associated multifunctional enzyme with low dehydrogenase activity toward r-3-hydroxybutyryl coenzyme a. | 2004 | 15345460 |
| direct observation of poly(3-hydroxybutyrate) depolymerase adsorbed on polyester thin film by atomic force microscopy. | poly[(r)-3-hydroxybutyrate] (phb) depolymerases adsorbed on poly(l-lactide) (plla) thin film were directly observed by atomic force microscopy (afm). a plla thin film of 100 nm thickness was prepared on a silicon wafer by spin-cast method. the plla thin film was treated at 220 degrees c and quenched to room temperature, resulting in the formation of a completely amorphous film with a smooth surface. then, the phb depolymerases from pseudomonas stutzeri ym1006 and ralstonia pickettii t1 were disp ... | 2004 | 15360268 |
| morphology and enzymatic degradation of oriented thin film of ultrahigh molecular weight poly[(r)-3-hydroxybutyrate]. | thin films of ultrahigh molecular weight poly[(r)-3-hydroxybutyrate] (p(3hb)) were sheared and isothermally crystallized at 100 degrees c. transmission electron microscopy and atomic force microscopy (afm) observations revealed that thick fibrous textures, on which lamellae are overgrown normal to the long axis of the fibril, run parallel to the shearing direction. a selected area electron diffraction pattern taken from the fibrils exhibits a fiber pattern of p(3hb) alpha-modification, and the c ... | 2004 | 15360288 |
| enumeration of soil bacteria with the green fluorescent nucleic acid dye sytox green in the presence of soil particles. | total counts in soils are usually determined using fluorescent dyes, such as dapi or sybr green, due to fluorescence enhancement if they are bound to nucleic acids. unfortunately, these commonly used dyes stain soil particles as well. therefore, besides fluorescence enhancement, sufficient spectral differentiation is also required. we present a new procedure that overcomes the problems of visualising bacteria on surfaces in soil and avoids the separation of soil particles to a large extent. spec ... | 2004 | 15369855 |
| improved laboratory diagnosis of bacterial and fungal infections in patients with hematological malignancies using pcr and ribosomal rna sequence analysis. | during october 1999 to november 2000, 98 blood culture specimens from the same number of febrile episodes originating from 49 patients with hematological malignancies were examined for the presence of eubacteria and fungi based on 16s rrna gene and the 5.8, 18 and 28s rrna combined with in vitro pcr amplification and sequencing, in addition to conventional blood culture laboratory techniques. nineteen of the samples were associated with positive blood cultures. eubacterial (16s rrna) pcr detecte ... | 2004 | 15370218 |
| characterization of phenol and trichloroethene degradation by the rhizobium ralstonia taiwanensis. | ralstonia taiwanensis is a root nodule bacterium originally isolated from mimosa sp. in southern taiwan. some strains of r. taiwanensis demonstrated the ability to grow on medium containing phenol as the sole carbon source, especially strain tj86, which was able to survive and grow at phenol concentrations of up to 900 mg/l. the dependence of the phenol degradation rate on the phenol concentration can be described by haldane's model with a low ks (the apparent half-saturation constant) of 5.46 m ... | 2004 | 15380556 |
| properties of an intracellular poly(3-hydroxybutyrate) depolymerase (phaz1) from rhodobacter spheroides. | the gene of an intracellular poly(3-hydroxybutyrate) (iphb) depolymerase from rhodobacter sphaeroides was cloned and sequenced. the nucleotide sequence of the cloned gene was homologous to that of the iphb depolymerase gene from ralstonia eutropha h16 (phaz1(reu)) and the gene was designated phaz1(rsh). phaz1(rsh) was purified from e. coli harboring an expression vector containing phaz1(rsh) and its properties were examined. phaz1(rsh) degraded amorphous phb granules, and the 3-hydroxybutyrate t ... | 2004 | 15386104 |
| pig slurry reduces the survival of ralstonia solanacearum biovar 2 in soil. | the effect of added pig slurry and solarization on the survival of ralstonia solanacearum biovar 2 strain 1609 in soil was analysed in soil microcosms and field plots. in addition, the invasion of potato plants by r. solanacearum and the development of disease symptoms were determined, as measures of induced disease suppressiveness. in untreated soil, r. solanacearum showed slow population declines in both microcosms and the field from, initially, 10(6-)10(7) to 10(3)-10(4) cfu.(g dry soil)(-1) ... | 2004 | 15467784 |
| a survey of the composition and diversity of bacterial populations in bleached kraft pulp-mill wastewater secondary treatment systems. | bacterial community compositions from 10 pulp- and paper-mill treatment systems were compared using both traditional and molecular techniques. 16s-rflp (random fragment length polymorphisms) analysis was used to examine the genotypic profiles of the whole bacterial community of each treatment system. although all the communities shared approximately 60% of their dna band pattern, as determined by computer-assisted cluster analysis, each community displayed a unique profile that was stable over t ... | 2004 | 15467789 |
| microbial polythioesters. | this feature article describes the current knowledge on biosynthesis of polythioesters (ptes), which are exclusively accumulated by microorganisms capable to synthesize the well-known polyhydroxyalkanoates (phas). two bacterial pte biosynthesis systems are discussed, both are depending on the cultivation conditions and appropriate feeding regimes. the first system comprises the production of pte copolymers by ralstonia eutropha, and the second system has been established in recombinant escherich ... | 2004 | 15468206 |
| biosynthesis and compositional regulation of poly[(3-hydroxybutyrate)-co-(3-hydroxyhexanoate)] in recombinant ralstonia eutropha expressing mutated polyhydroxyalkanoate synthase genes. | a new strategy for bacterial polyhydroxyalkanoate (pha) production by recombinant ralstonia eutropha phb(-)4 harboring mutated pha synthase genes (phac(ac)) from aeromona caviae was investigated. the strain harboring wild-type phac(ac) gene produced a pha copolymer consisting of (r)-3-hydroxybutyrate and (r)-3-hydroxyhexanoate [p(3hb-co-3hhx)] with 3.5 mol-% of 3hhx fraction from soybean oil. when the mutants of phac(ac) gene were applied to this production system, 3hhx fraction in copolymers wa ... | 2004 | 15468213 |
| mass spectrometry feedback control for synthesis of polyhydroxyalkanoate granule microstructures in ralstonia eutropha. | polyhydroxyalkanoate (pha) granules with core-shell layered microstructure were synthesized in ralstonia eutropha using periodic feeding of valeric acid into a growth medium containing excess fructose. the o2 consumption and co2 evolution rates, determined by off-gas mass spectrometry, have been used as sensitive measures to indicate the type of nutrients utilized by r. eutropha during pha synthesis. domains of poly-3-hydroxybutyrate (phb) were formed during polymer storage conditions when only ... | 2004 | 15468214 |
| metabolic engineering for the production of copolyesters consisting of 3-hydroxybutyrate and 3-hydroxyhexanoate by aeromonas hydrophila. | aeromonas hydrophila 4ak4 was able to synthesize copolyesters consisting of 3-hydroxybutyrate (3hb) and about 15 mol-% 3-hydroxyhexanoate (3hhx) (phbhhx) when grown in long chain fatty acids such as dodecanoate regardless of growth conditions. to regulate the unit fraction in phbhhx, phba and phbb genes encoding beta-ketothiolase and acetoacetyl-coa reductase in ralstonia eutropha, were introduced into a. hydrophila 4ak4. when gluconate was used as cosubstrate of dodecanoate, the recombinant pro ... | 2004 | 15468215 |
| in-situ atomic force microscopy observation of enzymatic degradation in poly(hydroxyalkanoic acid) thin films: normal and constrained conditions. | the enzymatic degradation of lamellar crystals in poly(hydroxyalkanoic acid) thin films has been visualized by using in-situ dynamic force mode (tapping mode) atomic force microscopy (afm) in buffer solution. it was found that poly(hydroxybutyric acid) (phb) depolymerase from ralstonia pickettii t1 degraded the thin surface layers formed at room temperature first, and that lamellar crystals formed at the crystallization temperature (110 degrees c) were eroded from the crystallographic a-axis to ... | 2004 | 15468218 |
| a stereoselective carbon-nitrogen lyase from ralstonia sp. slrs7 cleaves two of three isomers of iminodisuccinate. | following biodegradation tests according to the oecd guidelines for testing of chemicals 301f different degradation rates were observed for the three stereoisomers of iminodisuccinate (ids). a strain was isolated from activated sludge, which used two of three isomers, r,s-ids and s,s-ids, as sole source of carbon, nitrogen, and energy. the isolated strain was identified by 16s-rdna and referred to as ralstonia sp. slrs7. an ids-degrading lyase was isolated from the cell-free extract. the enzyme ... | 2004 | 15473552 |
| identification of an antibacterial compound, benzylideneacetone, from xenorhabdus nematophila against major plant-pathogenic bacteria. | an entomopathogenic bacterium, xenorhabdus nematophila, is known to have potent antibiotic activities to maintain monoxenic condition in its insect host for effective pathogenesis and ultimately for optimal development of its nematode symbiont, steinernema carpocapsae. in this study we assess its antibacterial activity against plant-pathogenic bacteria and identify its unknown antibiotics. the bacterial culture broth had significant antibacterial activity that increased with development of the b ... | 2004 | 15476972 |
| in silico evaluation of molecular probes for detection and identification of ralstonia solanacearum and clavibacter michiganensis subsp. sepedonicus. | ralstonia solanacerum and clavibacter michiganensis subsp. sepedonicus are the two most relevant bacterial pathogens of potato for which a large number of molecular diagnostic methods using specific dna sequences have been developed. about one hundred oligonucleotides have been described and thoroughly tested experimentally. after having compiled and evaluated all these primers and probes in silico to check their specificity, many discrepancies were found. a detailed analysis permitted the recog ... | 2004 | 15490560 |
| [case report: nosocomial ralstonia pickettii infection in neonatal intensive care unit]. | although ralstonia pickettii was known as a saprophytic species, it has been isolated in nosocomial infections in recent years. in this case report, r. pickettii infection of a neonate in the neonatal intensive care unit (icu) was presented. r. pickettii was isolated from the blood cultures of the neonate and also from the incubator and distilled water of the incubator. the isolates revealed identical biochemical and physiological characteristics. the strains were identified by conventional test ... | 2004 | 15490846 |
| nife hydrogenase active site biosynthesis: identification of hyp protein complexes in ralstonia eutropha. | biosynthesis of the nife hydrogenase active site is a complex process involving the action of the hyp proteins: hypa-hypf. here we investigate the mechanism of nife site biosynthesis in ralstonia eutropha by examining the interactions between hypc, hypd, hype, and hypf1. using an affinity purification procedure based on the strep-tag ii, we purified hypc and hype from different genetic backgrounds as complexes with other hydrogenase-related proteins and characterized them using immunological ana ... | 2004 | 15491154 |
| controlling the regiospecific oxidation of aromatics via active site engineering of toluene para-monooxygenase of ralstonia pickettii pko1. | a primary goal of protein engineering is to control catalytic activity. here we show that through mutagenesis of three active site residues, the catalytic activity of a multicomponent monooxygenase is altered so that it hydroxylates all three positions of toluene as well as both positions of naphthalene. hence, for the first time, an enzyme has been engineered so that its regiospecific oxidation of a substrate can be controlled. through the a107g mutation in the alpha-subunit of toluene para-mon ... | 2005 | 15498762 |
| screening procedures for selecting rhizobacteria with biocontrol effects upon fusarium verticillioides growth and fumonisin b1 production. | screening is a critical step in the discovery of microbial agents that can exert biological control of fusarium verticillioides at the root level. the objectives of this research were to determine the utility of a niche overlap index to realise the first screening of maize rhizobacterial isolates during different water activities. studies were conducted to evaluate various methods for second screening with different modes of action. the antifungal activity of bacterial isolates through antibiosi ... | 2004 | 15501652 |
| oxa-60, a chromosomal, inducible, and imipenem-hydrolyzing class d beta-lactamase from ralstonia pickettii. | a chromosomally encoded oxacillinase, oxa-22, had been characterized from ralstonia pickettii pic-1 that did not explain by itself the resistance profile of this strain to beta-lactams. thus, further analysis of the genetic background of this species led to the identification of another oxacillinase, oxa-60, that was expressed only after beta-lactam induction. this chromosomally encoded oxacillinase shared 19% amino acid identity with oxa-22. it has a narrow-spectrum hydrolysis profile that incl ... | 2004 | 15504844 |
| mutation effects of a conserved alanine (ala510) in type i polyhydroxyalkanoate synthase from ralstonia eutropha on polyester biosynthesis. | type i polyhydroxyalkanoate (pha) synthases, as represented by ralstonia eutropha enzyme (phac(re)), have narrow substrate specificity toward (r)-3-hydroxyacyl-coenzyme a with acyl chain length of c3-c5 to yield pha polyesters. in this study, saturation point mutagenesis of a highly conserved alanine at position 510 (a510) in phac(re) was carried out to investigate the effects on the polymerization activity and the substrate specificity for in vivo pha biosynthesis in bacterial cells. a series o ... | 2004 | 15508175 |
| biosynthesis of hydroxydiphenylacetylene by regiospecific monooxygenation. | bacterial monooxygenase enzymes catalyze a regiospecific single-step hydroxylation of diphenylacetylene to yield meta- and para-hydroxydiphenylacetylene. | 2004 | 15514786 |
| characteristics of zinc transport by two bacterial cation diffusion facilitators from ralstonia metallidurans ch34 and escherichia coli. | czcd from ralstonia metallidurans and zitb from escherichia coli are prototypes of bacterial members of the cation diffusion facilitator (cdf) protein family. expression of the czcd gene in an e. coli mutant strain devoid of zitb and the gene for the zinc-transporting p-type atpase znta rendered this strain more zinc resistant and caused decreased accumulation of zinc. czcd, purified as an amino-terminal streptavidin-tagged protein, bound zn2+, co2+, cu2+, and ni2+ but not mg2+, mn2+, or cd2+, a ... | 2004 | 15516561 |
| efficient micropropagation of ensete ventricosum applying meristem wounding: a three-step protocol. | a highly efficient three-step protocol for in vitro propagation of ensete ventricosum (enset) was developed that consisted of initiation, bud proliferation, and shoot elongation and rooting stages. at the initiation stage, it was crucial to use shoot tips (5-8 mm) with subtending corm tissues as explants to obtain growth. the addition of 0.5-1% (w/v) activated charcoal to the medium was essential to prevent phenol exudation which otherwise leads to the loss of cultures. during the bud proliferat ... | 2004 | 15517275 |
| genetic screening of hrp type iii-related pathogenicity genes controlled by the hrpb transcriptional activator in ralstonia solanacearum. | as in many other gram-negative phytopathogenic bacteria, the hrp type iii secretion system is essential for the pathogenicity of ralstonia solanacearum on host plants. the expression of most of the type iii effector genes previously isolated from r. solanacearum is co-regulated with those of hrp genes by an arac-type transcriptional activator, hrpb. in order to isolate type iii-related pathogenicity genes, we screened hrpb-regulated genes in r. solanacearum. using a transposon-based system, we i ... | 2004 | 15522073 |
| molecular hydrogen from water radiolysis as an energy source for bacterial growth in a basin containing irradiating waste. | although being deionized, filtered and therefore normally deeply oligotrophic, the water from a basin containing irradiating waste presented relatively high bacterial concentrations (ca 10(5) cfu ml(-1)) and biofilm development at its surface and on the walls. this water was characterized by a high concentration of molecular h2 due to water radiolysis, while its electrochemical potential was around +400 mv due the presence of dissolved o2 and active oxygen compounds. this combination of h2 avail ... | 2004 | 15522503 |
| engineering of chimeric class ii polyhydroxyalkanoate synthases. | pha synthase is a key enzyme involved in the biosynthesis of polyhydroxyalkanoates (phas). using a combinatorial genetic strategy to create unique chimeric class ii pha synthases, we have obtained a number of novel chimeras which display improved catalytic properties. to engineer the chimeric pha synthases, we constructed a synthetic phac gene from pseudomonas oleovorans (phac1po) that was devoid of an internal 540-bp fragment. randomly amplified pcr products (created with primers based on conse ... | 2004 | 15528546 |
| enzymatic degradation processes of lamellar crystals in thin films for poly[(r)-3-hydroxybutyric acid] and its copolymers revealed by real-time atomic force microscopy. | enzymatic degradation processes of flat-on lamellar crystals in melt-crystallized thin films of poly[(r)-3-hydroxybutyric acid] (p(3hb)) and its copolymers were characterized by real-time atomic force microscopy (afm) in a phosphate buffer solution containing phb depolymerase from ralstonia pickettii t1. fiberlike crystals with regular intervals were generated along the crystallographic a axis at the end of lamellar crystals during the enzymatic degradation. the morphologies and sizes of the fib ... | 2004 | 15530032 |
| ralstonia solanacearum iron scavenging by the siderophore staphyloferrin b is controlled by phca, the global virulence regulator. | phca is a transcriptional regulator that activates expression of multiple virulence genes in the plant pathogen ralstonia solanacearum. relative to their wild-type parents, phca mutants overproduced iron-scavenging activity detected with chrome azurol s siderophore detection medium. transposon mutagenesis of strain aw1-pc (phca1) generated strain gb6, which was siderophore negative but retained weak iron-scavenging activity. the ssd gene inactivated in gb6 encodes a protein similar to group iv a ... | 2004 | 15547261 |
| a dna region recognized by the nitric oxide-responsive transcriptional activator norr is conserved in beta- and gamma-proteobacteria. | the sigma(54)-dependent regulator norr activates transcription of target genes in response to nitric oxide (no) or no-generating agents. in ralstonia eutropha h16, norr activates transcription of the dicistronic norab operon that encodes nora, a protein of unknown function, and norb, a nitric oxide reductase. a constitutively activating norr derivative (norr'), in which the n-terminal signaling domain was replaced by male, specifically bound to the norab upstream region as revealed by gel retard ... | 2004 | 15547270 |
| the chromosomally encoded cation diffusion facilitator proteins dmef and fief from wautersia metallidurans ch34 are transporters of broad metal specificity. | genomic sequencing of the beta-proteobacterium wautersia (previously ralstonia) metallidurans ch34 revealed the presence of three genes encoding proteins of the cation diffusion facilitator (cdf) family. one, czcd, was previously found to be part of the high-level metal resistance system czc that mediates the efflux of co(ii), zn(ii), and cd(ii) ions catalyzed by the czccba cation-proton antiporter. the second cdf protein, fief, is probably mainly a ferrous iron detoxifying protein but also medi ... | 2004 | 15547276 |
| high level recombinant protein expression in ralstonia eutropha using t7 rna polymerase based amplification. | we report further development of a novel recombinant protein expression system based on the gram-negative bacterium, ralstonia eutropha. in this study, we were able to express soluble, active, organophosphohydrolase (oph), a protein that is prone to inclusion body formation in escherichia coli, at titers greater than 10 g/l in high cell density fermentation. this represents a titer that is approximately 100-fold greater than titers previously reported in e. coli for this enzyme. r. eutropha stra ... | 2004 | 15555942 |
| identification of a novel virulence factor in burkholderia cenocepacia h111 required for efficient slow killing of caenorhabditis elegans. | burkholderia cenocepacia h111, which was isolated from a cystic fibrosis patient, employs a quorum-sensing (qs) system, encoded by cep, to control the expression of virulence factors as well as the formation of biofilms. the qs system is thought to ensure that pathogenic traits are expressed only when the bacterial population density is high enough to overwhelm the host before it is able to mount an efficient response. while the wild-type strain effectively kills the nematode caenorhabditis eleg ... | 2004 | 15557647 |
| isolation and characterization of soybean-associated bacteria and their potential for plant growth promotion. | endophytic and epiphytic bacteria were isolated from two soybean cultivars (foscarin and cristalina). significant differences were observed in bacterial population densities in relation to season of isolation, soybean growth phase and the tissues from which the isolates were obtained. the isolates were identified by partial 16s rdna sequence analysis, with most of the isolates belonging to the pseudomonaceae, burkholderiacea and enterobacteriaceae groups. the potential of the isolates for plant ... | 2004 | 15560822 |
| chlorinated aliphatic hydrocarbon-induced degradation of trichloroethylene in wautersia numadzuensis sp. nov. | two strains of trichloroethylene (tce)-degrading bacteria were isolated from soils at polluted and unpolluted sites. the isolates, strains te26(t) and k6, showed co-substrate-independent tce-degrading activity. tce degradation was accelerated by preincubation with tetrachloroethylene, cis-dichloroethylene (dce) and 1,1-dce. tce-degrading activities of strains te26(t) and k6 were 0.23, 0.24 micromol min(-1) g(-1) dry cells, respectively. 16s rdna sequences of strains te26(t) and k6 were almost id ... | 2005 | 15570416 |
| a previously unexposed forest soil microbial community degrades high levels of the pollutant 2,4,6-trichlorophenol. | 2,4,6-trichlorophenol (2,4,6-tcp) is a hazardous pollutant that is efficiently degraded by some aerobic soil bacterial isolates under laboratory conditions. the degradation of this pollutant in soils and its effect on the soil microbial community are poorly understood. we report here the ability of a previously unexposed forest soil microbiota to degrade high levels of 2,4,6-tcp and describe the changes in the soil microbial community found by terminal restriction fragment length polymorphism (t ... | 2004 | 15574963 |
| effect of process variables on supercritical fluid disruption of ralstonia eutropha cells for poly(r-hydroxybutyrate) recovery. | this research focuses on the disruption of the gram-negative bacterium ralstonia eutropha cells by supercritical co2 for poly(r-hydroxybutyrate) (phb) recovery. the variables affecting cell disruption such as drying strategy, type of modifier, and cultivation time, as well as operating pressure, temperature, and repeated release of supercritical co2 pressure, have been studied. effect of this disruption technique on phb molecular mass was also investigated. phb recovery was examined using a comb ... | 2004 | 15575709 |
| role of a nosx homolog in streptococcus gordonii in aerobic growth and biofilm formation. | oral streptococci such as streptococcus gordonii are facultative anaerobes that initiate biofilm formation on tooth surfaces. an isolated s. gordonii::tn917-lac biofilm-defective mutant contained a transposon insertion in an open reading frame (orf) encoding a homolog of nosx of ralstonia eutropha, a putative maturation factor of nitrous oxide reductase. located downstream are two genes, qor1 and qor2, predicted to encode two putative nadph quinone oxidoreductases. these three genes are cotransc ... | 2004 | 15576767 |
| characterization of clinically isolated ralstonia mannitolilytica strains using random amplification of polymorphic dna (rapd) typing and antimicrobial sensitivity, and comparison of the classification efficacy of phenotypic and genotypic assays. | ralstonia mannitolilytica strains isolated between february 2002 and march 2004 from 30 episodes of infection in 26 patients at vienna university hospital were characterized. twenty-four of the episodes occurred within a 7 month period, suggesting they were outbreak-related, although no common source of infection was identified. the isolates were assayed using pcr to confirm species identification. random amplification of polymorphic dna (rapd) typing classified the r. mannitolilytica isolates i ... | 2005 | 15591256 |
| high-level heterologous expression and properties of a novel lipase from ralstonia sp. m1. | the mature lipase lipa and its 56aa-truncated chaperone deltalipbhis (with 6xhis-tag) from ralstonia sp. m1 were over-expressed in escherichia coli bl21 under the control of t7 promoter with a high level of 70 and 12mg protein per gram of wet cells, respectively. the simply purified lipase lipa was effectively refolded by ni-nta purified chaperone deltalipbhis in molar ratio 1:1 at 4 degrees c for 24 hours in h2o. the in vitro refolded lipase lipa had an optimal activity in the temperature range ... | 2005 | 15596365 |