| relationship between avirulence gene (avra) diversity in ralstonia solanacearum and bacterial wilt incidence. | bacterial wilt, caused by ralstonia solanacearum, is a serious disease of tobacco in north and south carolina. in contrast, the disease rarely occurs on tobacco in georgia and florida, although bacterial wilt is a common problem on tomato. we investigated whether this difference in disease incidence could be explained by qualitative characteristics of avirulence gene avra in the r. solanacearum population in the southeastern united states. sequence analysis established that wild-type avra has a ... | 2004 | 15597743 |
| tomato stress-responsive factor tsrf1 interacts with ethylene responsive element gcc box and regulates pathogen resistance to ralstonia solanacearum. | ethylene responsive factors (erfs) are important in regulating plant pathogen resistance, abiotic stress tolerance and plant development. recent studies have greatly enlarged the erf protein family and revealed more important roles of erfs in plants. here, we report our finding of a tomato erf protein tsrf1, which is transcriptionally up-regulated by ethylene, salicylic acid, or ralstonia solanacearum strain bj1057 infection. biochemical analysis indicates that tsrf1 specifically interacts in vi ... | 2004 | 15604719 |
| [physicochemical properties of two-component polyhydroxyalkanoates based on 3-hydroxybutyrate and 3-hydroxyvalerate]. | a series of two-component polyhydroxyalkanoates consisting of hydroxybutyrate and hydroxyvalerate monomer at different ratios were synthesized using the bacterium ralstonia eutropha b5786. the properties of polyhydroxyalkanoates were compared with those of the homopolymer of hydroxybutyric acid by x-ray structure analysis, ir spectroscopy, differential scanning calorimetry, and viscosimetry. with an increase in the molar fraction of hydroxyvalerate, an equalization of the ratio of the crystallin ... | 2004 | 15612544 |
| anti-fungal sesquiterpenoid from the root exudate of solanum abutiloides. | the solanum abutiloides plant is highly resistant to soil-borne pathogens such as fusarium oxysporum f. sp. melongenae, verticillium dahliae, and ralstonia solanacearum. this species is utilized as a mating source of resistant cultivars and is also used as a rootstock. the root exudate of solanum abutiloides was extracted from a soil system composed of charcoal and vermiculite. anti-fungal activity was found in the extract, and an active ingredient was isolated. the chemical structure of the act ... | 2004 | 15618642 |
| type iii secretion system cluster 3 is required for maximal virulence of burkholderia pseudomallei in a hamster infection model. | burkholderia pseudomallei, the etiological agent of melioidosis, is an animal pathogen capable of inducing a highly fatal septicemia. b. pseudomallei possesses three type iii secretion system (ttss) clusters, two of which (ttss1 and ttss2) are homologous to the ttss of the plant pathogen ralstonia solanacearum, and one (ttss3) is homologous to the salmonella spi-1 mammalian pathogenicity island. we have demonstrated that ttss3 is required for the full virulence of b. pseudomallei in a hamster mo ... | 2005 | 15621426 |
| antibacterial activity of cuminum cyminum l. and carum carvi l. essential oils. | essential oils extracted by hydrodistillation from fruits of cuminum cyminum l. and carum carvi l. were analyzed by gas chromatography (gc) and gc-mass spectrometry (ms). the main components of c. cyminum oil were p-mentha-1,4-dien-7-al, cumin aldehyde, gamma-terpinene, and beta-pinene, while those of the c. carvi oil were carvone, limonene, germacrene d, and trans-dihydrocarvone. antibacterial activity, determined with the agar diffusion method, was observed against gram-positive and gram-negat ... | 2005 | 15631509 |
| seasonal variation of ralstonia solanacearum biovar 2 populations in a spanish river: recovery of stressed cells at low temperatures. | the presence of ralstonia solanacearum biovar 2 in the watercourses of european countries is increasing, but little is known about its ecology in aquatic habitats. the detection of this pathogen in 2000 in one spanish river led us to study its population density at different locations on the river over a period of 3 years. during 2000 and 2001, the pathogen was recovered at low densities (10 to 80 cfu/ml) by direct plating on modified smsa agar from water samples at 14 degrees c or higher, but i ... | 2005 | 15640181 |
| contribution of folate biosynthesis to ralstonia solanacearum proliferation in intercellular spaces. | the vigorous proliferation of ralstonia solanacearum oe1-1 in host intercellular spaces after the invasion of host plants is necessary for the virulence of this bacterium. a folate auxotroph, rm, in which a mini-tn5 transposon was inserted into pabb encoding para-aminobenzoate synthase component i, lost its ability to vigorously proliferate in intercellular spaces along with its systemic infectivity and virulence after inoculation into roots and infiltration into leaves of tobacco plants. comple ... | 2005 | 15640216 |
| structural and oxidation-state changes at its nonstandard ni-fe site during activation of the nad-reducing hydrogenase from ralstonia eutropha detected by x-ray absorption, epr, and ftir spectroscopy. | structure and oxidation state of the ni-fe cofactor of the nad-reducing soluble hydrogenase (sh) from ralstonia eutropha were studied employing x-ray absorption spectroscopy (xas) at the ni k-edge, epr, and ftir spectroscopy. the sh comprises a nonstandard (cn)ni-fe(cn)(3)(co) site; its hydrogen-cleavage reaction is resistant against inhibition by dioxygen and carbon monoxide. simulations of the xanes and exafs regions of xas spectra revealed that, in the oxidized sh, the ni(ii) is six-coordinat ... | 2005 | 15643882 |
| two cases of ralstonia pickettii bacteremias in a pediatric oncology unit requiring removal of the port-a-caths. | ralstonia pickettii is an aerobic, gram-negative bacterium causing bacteremia following the use of contaminated saline vials, respiratory therapy solutions, skin disinfectants, blood culture mediums, and water supplies. it is rarely associated with human infections. the authors report two cases of r. pickettii bacteremia in patients with port-a-caths that could be treated only by removal of the ports. | 2005 | 15654276 |
| transgenic tomato plants expressing an arabidopsis thionin (thi2.1) driven by fruit-inactive promoter battle against phytopathogenic attack. | tomato is one of the most important crop plants; however, attacks by pathogens can cause serious losses in production. in this report, we explore the potential of using the arabidopsis thionin (thi2.1) gene to genetically engineer enhanced resistance to multiple diseases in tomato. potential thionin toxicity in fruits was negated by the use of a fruit-inactive promoter to drive the thi2.1 gene. in transgenic lines containing rb7/thi2.1, constitutive thi2.1 expression was detected in roots and in ... | 2005 | 15657715 |
| non-standard structures of the ni-fe cofactor in the regulatory and the nad-reducing hydrogenases from ralstonia eutropha. | spectroscopy on two oxygen-insensitive ni-fe hydrogenases from ralstonia eutropha (nad-reducing, soluble hydrogenase; hydrogen sensor, regulatory hydrogenase) reveals non-standard catalytic behaviour and unique structures of their ni-fe cofactors. possible mechanistic implications are briefly discussed. | 2005 | 15667255 |
| molecular characterization of uptake hydrogenase in frankia. | a molecular characterization of uptake hydrogenase in frankia was performed by using two-dimensional gel electrophoresis, matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry, pcr amplification and southern blotting. a polypeptide of approx. 60 kda was recognized in frankia ugl011102, avci1 and kb5 on the two-dimensional gel by blotting with ralstonia eutropha (hox g) antibody. further analysis by ms resulted in a peptide 'fingerprint', which was similar to the membrane-b ... | 2005 | 15667266 |
| a hydrogen-sensing multiprotein complex controls aerobic hydrogen metabolism in ralstonia eutropha. | h(2) is an attractive energy source for many microorganisms and is mostly consumed before it enters oxic habitats. thus aerobic h(2)-oxidizing organisms receive h(2) only occasionally and in limited amounts. metabolic adaptation requires a robust oxygen-tolerant hydrogenase enzyme system and special regulatory devices that enable the organism to respond rapidly to a changing supply of h(2). the proteobacterium ralstonia eutropha strain h16 that harbours three [nife] hydrogenases perfectly meets ... | 2005 | 15667276 |
| dna binding properties of the escherichia coli nitric oxide sensor norr: towards an understanding of the regulation of flavorubredoxin expression. | nitric oxide is an intermediate of denitrification, and is one of the radical species deployed by macrophages against invading pathogens, therefore bacterial responses to no are of considerable importance. the escherichia coli flavorubredoxin and its associated oxidoreductase reduce no to nitrous oxide under anaerobic conditions, and are encoded by the norvw transcription unit. expression of norvw requires the no sensing regulatory protein norr and is dependent on rna polymerase containing the a ... | 2005 | 15667300 |
| transcriptional regulation of nitric oxide reduction in ralstonia eutropha h16. | nitric oxide reduction in ralstonia eutropha h16 is catalysed by the quinol-dependent no reductase norb. norb and the adjacent nora form an operon that is controlled by the sigma(54)-dependent transcriptional activator norr in response to no. a norr derivative containing male in place of the n-terminal domain binds to a 73 bp region upstream of nora that includes three copies of the putative upstream activator sequence ggt-(n(7))-acc. mutations altering individual bases of this sequence resulted ... | 2005 | 15667304 |
| a novel lipase/chaperone pair from ralstonia sp. m1: analysis of the folding interaction and evidence for gene loss in r. solanacearum. | a microbial strain (referred to as m1) that produces an extracellular lipase was isolated from a soil sample in vietnam, and identified as a ralstonia species by partial sequencing of its 16s rdna. a genomic library was constructed from pst i fragments, and a colony showing lipase activity was selected for further analysis. sequencing of the 4.7-kb insert in this clone (named m1-72) revealed one incomplete and three complete orfs, predicted to encode a partial hypothetical glutaminyl trna synthe ... | 2004 | 15668771 |
| production of poly(3-hydroxybutyrate) by solid-state fermentation with ralstonia eutropha. | the use of solid-state fermentation is examined as a low-cost technology for the production of poly(hydroxyalkanoates) (phas) by ralstonia eutropha. two agroindustrial residues (babassu and soy cake) were evaluated as culture media. the maximum poly(hydroxybutyrate) (phb) yield was 1.2 mg g(-1) medium on soy cake in 36 h, and 0.7 mg g(-1) medium on babassu cake in 84 h. addition of 2.5% (w/w) sugar cane molasses to soy cake increased phb production to 4.9 mg g(-1) medium in 60 h. under these con ... | 2004 | 15672227 |
| aerobic biodegradation of n-nitrosodimethylamine (ndma) by axenic bacterial strains. | the water contaminant n-nitrosodimethylamine (ndma) is a probable human carcinogen whose appearance in the environment is related to the release of rocket fuel and to chlorine-based disinfection of water and wastewater. although this compound has been shown to be biodegradable, there is minimal information about the organisms capable of this degradation, and little is understood of the mechanisms or biochemistry involved. this study shows that bacteria expressing monooxygenase enzymes functional ... | 2005 | 15672376 |
| the bphc gene-encoded 2,3-dihydroxybiphenyl-1,2-dioxygenase is involved in complete degradation of dibenzofuran by the biphenyl-degrading bacterium ralstonia sp. sbug 290. | biphenyl-degrading bacteria are able to metabolize dibenzofuran via lateral dioxygenation and meta-cleavage of the dihydroxylated dibenzofuran produced. this degradation was considered to be incomplete because accumulation of a yellow-orange ring-cleavage product was observed. in this study, we want to characterize the 1,2-dihydroxydibenzofuran cleaving enzyme which is involved in dibenzofuran degradation in the bacterium ralstonia sp. sbug 290. | 2005 | 15715866 |
| overexpression of a pepper basic pathogenesis-related protein 1 gene in tobacco plants enhances resistance to heavy metal and pathogen stresses. | a pepper gene, cabpr1, which encodes basic pathogenesis-related protein 1, has been reported to be strongly induced after ethephon treatment, wounding, and tobacco mosaic virus infection. the potential role of cabpr1 in tolerance of biotic or abiotic stresses was examined in transgenic nicotiana tabacum cv. xanthi plants. overexpression of cabpr1 in tobacco plants enhanced tolerance not only to heavy metal stresses, but also to the oomycete pathogen phytophthora nicotianae, and the bacterial pat ... | 2005 | 15719238 |
| regiospecific oxidation of naphthalene and fluorene by toluene monooxygenases and engineered toluene 4-monooxygenases of pseudomonas mendocina kr1. | the regiospecific oxidation of the polycyclic aromatic hydrocarbons naphthalene and fluorene was examined with escherichia coli strains expressing wildtype toluene 4-monooxygenase (t4mo) from pseudomonas mendocina kr1, toluene para-monooxygenase (tpmo) from ralstonia pickettii pko1, toluene ortho-monooxygenase (tom) from burkholderia cepacia g4, and toluene/ortho-xylene monooxygenase (tomo) from p. stutzeri ox1. t4mo oxidized toluene (12.1+/-0.8 nmol/min/mg protein at 109 microm), naphthalene (7 ... | 2005 | 15723332 |
| control of tomato bacterial wilt without disinfection using a new functional polymer that captures microbial cells alive on the surface and is highly biodegradable. | this report describes a green chemical method for controlling soil-borne plant diseases without disinfection using an equimolar copolymer of n-benzyl-4-vinylpyridinium chloride with styrene (pbvp-co-st) that captures microbial cells alive on the surface and is highly biodegradable. tomato bacterial wilt caused by ralstonia solanacearum was controlled by the addition of sawdust coated with pbvp-co-st prior to transplantation. this effected 87% reduction in appearance and 89% reduction in the inde ... | 2005 | 15725658 |
| effect of over-expression of phasin gene from aeromonas hydrophila on biosynthesis of copolyesters of 3-hydroxybutyrate and 3-hydroxyhexanoate. | the gene phapah, encoding the protein phasin that is associated with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (phbhhx) granule of aeromonas hydrophila 4ak4, was cloned and characterized. recombinant strains harboring additional copies of the phasin gene (phapah) and the polyhydroxyalkanoate (pha) synthase gene (phacah) accumulated phbhhx copolyesters consisting of 21 mol% 3-hydroxyhexanoate (3hhx) as compared to 14 mol% 3hhx produced by wild type strain. the molecular weight of phbhhx produ ... | 2005 | 15727816 |
| biosynthesis of polyhydroxyalkanoate (pha) copolymer from fructose using wild-type and laboratory-evolved pha synthases. | eleven laboratory-evolved polyhydroxyalkanoate (pha) synthases which originated from pseudomonas sp. 61-3 enzyme (phac1(ps)), together with the wild-type enzyme, were applied for pha synthesis from fructose using ralstonia eutropha phb(-)4 as a host strain. the evolved phac1(ps) mutants had amino acid substitution(s) at position 325 and/or position 481. in these mutants, serine-325 (s325) was replaced by cysteine (c) or threonine (t), while glutamine-481 (q481) was replaced by lysine (k), methio ... | 2005 | 15729719 |
| stable-isotope probing of bacteria capable of degrading salicylate, naphthalene, or phenanthrene in a bioreactor treating contaminated soil. | [13c6]salicylate, [u-13c]naphthalene, and [u-13c]phenanthrene were synthesized and separately added to slurry from a bench-scale, aerobic bioreactor used to treat soil contaminated with polycyclic aromatic hydrocarbons. incubations were performed for either 2 days (salicylate, naphthalene) or 7 days (naphthalene, phenanthrene). total dna was extracted from the incubations, the "heavy" and "light" dna were separated, and the bacterial populations associated with the heavy fractions were examined ... | 2005 | 15746319 |
| detection of and response to signals involved in host-microbe interactions by plant-associated bacteria. | diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. this concept was first demonstrated for the members of the family rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and anima ... | 2005 | 15755957 |
| influence of homologous phasins (phap) on pha accumulation and regulation of their expression by the transcriptional repressor phar in ralstonia eutropha h16. | phasins play an important role in the formation of poly(3-hydroxybutyrate) [poly(3hb)] granules and affect their size. recently, three homologues of the phasin protein phap1 were identified in ralstonia eutropha strain h16. the functions of phap2, phap3 and phap4 were examined by analysis of r. eutropha h16 deletion strains (deltaphap1, deltaphap2, deltaphap3, deltaphap4, deltaphap12, deltaphap123 and deltaphap1234). when cells were grown under conditions permissive for poly(3hb) accumulation, t ... | 2005 | 15758228 |
| the pel genes of the pseudomonas aeruginosa pak strain are involved at early and late stages of biofilm formation. | pseudomonas aeruginosa is a gram-negative bacterium associated with nosocomial infections and cystic fibrosis. chronic bacterial infections are increasingly associated with the biofilm lifestyle in which microcolonies are embedded in an extracellular matrix. screening procedures for identifying biofilm-deficient strains have allowed the characterization of several key determinants involved in this process. biofilm-deficient p. aeruginosa pak strains affected in a seven-gene cluster called pel we ... | 2005 | 15758243 |
| fluorescence microscopical investigation of poly(3-hydroxybutyrate) granule formation in bacteria. | the early stages of poly(3-hydroxybutyrate) (phb) accumulation were analyzed in vivo by fluorescence microscopy in rhodospirillum rubrum, ralstonia eutropha, and in recombinant escherichia coli harboring the phb biosynthesis genes phacab of r. eutropha. phb granules were stained with nile red and by expression of a phasin-enhanced yellow fluorescent protein fusion protein. distribution of phb granules at the early stages of phb accumulation frequently occurred near the cell poles and near the ce ... | 2005 | 15762619 |
| synthesis of poly[(r)-3-hydroxybutyric acid) in the cytoplasm of pichia pastoris under oxygen limitation. | we have constructed a tandem gene expression cassette containing three ralstonia eutropha poly[(r)-3-hydroxybutyrate] (phb) synthesis genes under the control of the pichia pastoris glyceraldehyde-3-phosphate promoter and the green fluorescent protein (gfp) under the control of the p. pastoris alcohol oxidase promoter. the inducible gfp reporter protein has been used to rapidly isolate transformed strains with two copies of the entire expression cassette. the isolated strain exhibits gfp inductio ... | 2005 | 15762620 |
| reduction of unusual iron-sulfur clusters in the h2-sensing regulatory ni-fe hydrogenase from ralstonia eutropha h16. | the regulatory ni-fe hydrogenase (rh) from ralstonia eutropha functions as a hydrogen sensor. the rh consists of the large subunit hoxc housing the ni-fe active site and the small subunit hoxb containing fe-s clusters. the heterolytic cleavage of h(2) at the ni-fe active site leads to the epr-detectable ni-c state of the protein. for the first time, the simultaneous but epr-invisible reduction of fe-s clusters during ni-c state formation was demonstrated by changes in the uv-visible absorption s ... | 2005 | 15764814 |
| construction and evaluation of nagr-nagaa::lux fusion strains in biosensing for salicylic acid derivatives. | the nagr protein is a response regulatory protein found in the bacterium ralstonia sp. u2 that is involved in sensing for salicylic acid and the subsequent induction of the operon just upstream of its gene. the genes encoded for in this operon are involved in the degradation of salicylic acid. escherichia coli strain rfm443 carrying a fusion of the photorhabdus luminescens luxcdabe operon with the nagr gene and upstream region of the nagaa gene was constructed and characterized with respect to i ... | 2005 | 15767693 |
| characterization and properties of g4x mutants of ralstonia eutropha pha synthase for poly(3-hydroxybutyrate) biosynthesis in escherichia coli. | modification of the type i polyhydroxyalkanoate synthase of ralstonia eutropha (phac(re)) was performed through systematic in vitro evolution in order to obtain improved phac(re) having an enhanced activity of poly(3-hydroxybutyrate) (phb) synthesis in recombinant escherichia coli. for the first time, a beneficial g4d n-terminal mutation important for the enhancement of both phb content in dry cells and phac(re) level in vivo was identified. site-directed saturation mutagenesis at the g4 positio ... | 2005 | 15768438 |
| the effect of simulated microgravity on bacteria from the mir space station. | the effects of simulated microgravity on two bacterial isolates, sphingobacterium thalpophilium and ralstonia pickettii (formerly burkholderia pickettii), originally recovered from water systems aboard the mir space station were examined. these bacteria were inoculated into water, high and low concentrations of nutrient broth and subjected to simulated microgravity conditions. s. thalpophilium (which was motile and had flagella) showed no significant differences between simulated microgravity an ... | 2004 | 15773020 |
| chloromethylmuconolactones as critical metabolites in the degradation of chloromethylcatechols: recalcitrance of 2-chlorotoluene. | to elucidate possible reasons for the recalcitrance of 2-chlorotoluene, the metabolism of chloromethylcatechols, formed after dioxygenation and dehydrogenation by ralstonia sp. strain ps12 tetrachlorobenzene dioxygenase and chlorobenzene dihydrodiol dehydrogenase, was monitored using chlorocatechol dioxygenases and chloromuconate cycloisomerases partly purified from ralstonia sp. strain ps12 and wautersia eutropha jmp134. two chloromethylcatechols, 3-chloro-4-methylcatechol and 4-chloro-3-methyl ... | 2005 | 15774876 |
| the type iii-dependent hrp pilus is required for productive interaction of xanthomonas campestris pv. vesicatoria with pepper host plants. | the plant pathogenic bacterium xanthomonas campestris pv. vesicatoria expresses a type iii secretion system that is necessary for both pathogenicity in susceptible hosts and the induction of the hypersensitive response in resistant plants. this specialized protein transport system is encoded by a 23-kb hrp (hypersensitive response and pathogenicity) gene cluster. here we show that x. campestris pv. vesicatoria produces filamentous structures, the hrp pili, at the cell surface under hrp-inducing ... | 2005 | 15774889 |
| static suppression of tomato bacterial wilt by bacterial coagulation using a new functional polymer that coagulates bacterial cells and is highly biodegradable. | tomato bacterial wilt by ralstonia solanacearum was suppressed by coagulation of bacterial cells without disinfection using a copolymer of methyl methacrylate with n-benzyl-4-vinylpyridinium chloride in a molar ratio of 3:1 (pmma-co-bvp) as a polymeric coagulant for bacterial cells. when 10 mg/kg of pmma-co-bvp was added to soil before transplanting of tomato seedlings, and 2 mg/kg was supplemented once a week after transplanting, a 51% reduction of appearance and a 54% reduction of index of sym ... | 2005 | 15784982 |
| an exceptionally selective lead(ii)-regulatory protein from ralstonia metallidurans: development of a fluorescent lead(ii) probe. | | 2005 | 15800869 |
| a probable link between the deda protein and resistance to selenite. | to understand the molecular events involved in the reduction of selenite to non-toxic elemental selenium, 4000 clones of ralstonia metallidurans ch34 were produced by random tn5 transposon integration mutagenesis. eight mutants were able to resist up to 15 mm selenite while the mic for the wild-type strain was estimated as 4-6 mm selenite. the identification of the disrupted genes was carried out by southern blot analysis and inverse pcr. the three resistant mutants containing only one insertion ... | 2005 | 15808941 |
| control of the ralstonia solanacearum type iii secretion system (hrp) genes by the global virulence regulator phca. | expression of several virulence factors in the plant pathogen bacterium ralstonia solanacearum is controlled by a complex regulatory network, at the center of which is phca. we provide genetic evidence that phca also represses the expression of hrp genes that code for the type iii protein secretion system, a major pathogenicity determinant in this bacterium. the repression of hrp genes in complete medium is relieved in a phca mutant and two distinct signals, a quorum-sensing signal and complex n ... | 2005 | 15811321 |
| ralstonia pickettii and burkholderia cepacia complex bloodstream infections related to infusion of contaminated water for injection. | ralstonia pickettii and burkholderia cepacia complex isolates are causes of healthcare-associated infection related to contamination of intravenously administered products. based on microbiological and epidemiological data and molecular typing by pulsed-field gel electrophoresis, we report the occurrence of two outbreaks of r. pickettii and b. cepacia complex bloodstream infections. the first outbreak occurred from august 1995 to september 1996, and the second outbreak occurred from 28 march to ... | 2005 | 15823657 |
| [the synthesis of hydroxybutyrate and hydroxyvalerate copolymers by the bacterium ralstonia eutropha]. | the paper deals with the study of the synthesis of 3-hydroxybutyrate (3hb) and 3-hydroxyvalerate (3hv) copolymers by the bacterium ralstonia eutropha b-5786 grown under different carbon nutrition conditions (growth on carbon dioxide, fructose, and co2-valerate and fructose-valerate mixtures). the parameters to be analyzed included the yield of biomass, the yield, synthesis rate, and composition of copolymers, the activity of the key enzymes of polyhydroxyalkanoate (pha) synthesis (beta-ketothiol ... | 2005 | 15835780 |
| the soluble nad+-reducing [nife]-hydrogenase from ralstonia eutropha h16 consists of six subunits and can be specifically activated by nadph. | the soluble [nife]-hydrogenase (sh) of the facultative lithoautotrophic proteobacterium ralstonia eutropha h16 has up to now been described as a heterotetrameric enzyme. the purified protein consists of two functionally distinct heterodimeric moieties. the hoxhy dimer represents the hydrogenase module, and the hoxfu dimer constitutes an nadh-dehydrogenase. in the bimodular form, the sh mediates reduction of nad(+) at the expense of h(2). we have purified a new high-molecular-weight form of the s ... | 2005 | 15838039 |
| oxygen tolerance of the h2-sensing [nife] hydrogenase from ralstonia eutropha h16 is based on limited access of oxygen to the active site. | hydrogenases, abundant proteins in the microbial world, catalyze cleavage of h2 into protons and electrons or the evolution of h2 by proton reduction. hydrogen metabolism predominantly occurs in anoxic environments mediated by hydrogenases, which are sensitive to inhibition by oxygen. those microorganisms, which thrive in oxic habitats, contain hydrogenases that operate in the presence of oxygen. we have selected the h2-sensing regulatory [nife] hydrogenase of ralstonia eutropha h16 to investiga ... | 2005 | 15849358 |
| purification and characterization of chitinase b from moderately thermophilic bacterium ralstonia sp. a-471. | chitinase b was purified from a culture medium of ralstonia sp. a-471 by precipitation with (nh4)2so4 and column chromatography with deae-toyopearl 650 m and sephacryl s-200. the purified enzyme was homogeneous on sds-page. the molecular weight was 45,000 by sds-page. the optimum ph was 5.0 and stable ph was from 5.0 to 10.0. in the early stage of the reaction, chitinase b produced beta-anomer of (glcnac)2 from the substrate (glcnac)6, whereas (glcnac)4 produced almost at equilibrium, indicating ... | 2005 | 15849428 |
| protein engineering of the archetypal nitroarene dioxygenase of ralstonia sp. strain u2 for activity on aminonitrotoluenes and dinitrotoluenes through alpha-subunit residues leucine 225, phenylalanine 350, and glycine 407. | naphthalene dioxygenase (ndo) from ralstonia sp. strain u2 has not been reported to oxidize nitroaromatic compounds. here, saturation mutagenesis of ndo at position f350 of the alpha-subunit (nagac) created variant f350t that produced 3-methyl-4-nitrocatechol from 2,6-dinitrotoluene (26dnt), that released nitrite from 23dnt sixfold faster than wild-type ndo, and that produced 3-amino-4-methyl-5-nitrocatechol and 2-amino-4,6-dinitrobenzyl alcohol from 2-amino-4,6-dinitrotoluene (2a46dnt) (wild-ty ... | 2005 | 15866914 |
| isolation and characterization of a plasmid dna from periodontopathogenic bacterium, eikenella corrodens 1073, which affects pilus formation and colony morphology. | eikenella corrodens (ec) is one of a group of periodontopathogenic bacteria. a plasmid dna (8.7 kb) isolated from ec 1073 was designated pmu1. agarose gel electrophoresis and southern analysis suggested that pmu1-like plasmids were carried in 2 ec strains, including 1073, with higher hemagglutination (ha) activity than other strains. we determined the nucleotide sequence of this plasmid and identified 7 orfs. a homology search revealed that 4 orfs of pmu1 were homologous to orfs in pjtps1, found ... | 2005 | 15869847 |
| chemical forms of selenium in the metal-resistant bacterium ralstonia metallidurans ch34 exposed to selenite and selenate. | ralstonia metallidurans ch34, a soil bacterium resistant to a variety of metals, is known to reduce selenite to intracellular granules of elemental selenium (se(0)). we have studied the kinetics of selenite (se(iv)) and selenate (se(vi)) accumulation and used x-ray absorption spectroscopy to identify the accumulated form of selenate, as well as possible chemical intermediates during the transformation of these two oxyanions. when introduced during the lag phase, the presence of selenite increase ... | 2005 | 15870319 |
| identification of extracellular n-acylhomoserine lactone acylase from a streptomyces sp. and its application to quorum quenching. | n-acylhomoserine lactones (ahls) play an important role in regulating virulence factors in pathogenic bacteria. recently, the enzymatic inactivation of ahls, which can be used as antibacterial targets, has been identified in several soil bacteria. in this study, strain m664, identified as a streptomyces sp., was found to secrete an ahl-degrading enzyme into a culture medium. the ahlm gene for ahl degradation from streptomyces sp. strain m664 was cloned, expressed heterologously in streptomyces l ... | 2005 | 15870355 |
| molecular analysis of bacterial community based on 16s rdna and functional genes in activated sludge enriched with 2,4-dichlorophenoxyacetic acid (2,4-d) under different cultural conditions. | differential emergence and diversity of bacterial communities from activated sludge in response to varied cultural conditions using 2,4-dichlorophenoxyacetic acid (2,4-d) were investigated by coupling molecular analyses based on 16s rdna with functional genes. we employed three different cultural conditions: (1) a culture sequentially fed a high concentration (300 mg/l) of 2,4-d (hs); (2) a culture continuously fed a low concentration (10 mg/l) of 2,4-d (lc); and (3) a serial batch culture in wh ... | 2004 | 15883866 |
| kinetic studies of polyhydroxybutyrate granule formation in wautersia eutropha h16 by transmission electron microscopy. | wautersia eutropha, formerly known as ralstonia eutropha, a gram-negative bacterium, accumulates polyhydroxybutyrate (phb) as insoluble granules inside the cell when nutrients other than carbon are limited. in this paper, we report findings from kinetic studies of granule formation and degradation in w. eutropha h16 obtained using transmission electron microscopy (tem). in nitrogen-limited growth medium, the phenotype of the cells at the early stages of granule formation was revealed for the fir ... | 2005 | 15901706 |
| the mechanism of inactivation of 3-hydroxyanthranilate-3,4-dioxygenase by 4-chloro-3-hydroxyanthranilate. | 3-hydroxyanthranilate-3,4-dioxygenase (had) is a non-heme fe(ii) dependent enzyme that catalyzes the oxidative ring-opening of 3-hydroxyanthranilate to 2-amino-3-carboxymuconic semialdehyde. the enzymatic product subsequently cyclizes to quinolinate, an intermediate in the biosynthesis of nicotinamide adenine dinucleotide. quinolinate has also been implicated in important neurological disorders. here, we describe the mechanism by which 4-chloro-3-hydroxyanthranilate inhibits the had catalyzed re ... | 2005 | 15909977 |
| structural studies on 3-hydroxyanthranilate-3,4-dioxygenase: the catalytic mechanism of a complex oxidation involved in nad biosynthesis. | 3-hydroxyanthranilate-3,4-dioxygenase (had) catalyzes the oxidative ring opening of 3-hydroxyanthranilate in the final enzymatic step of the biosynthetic pathway from tryptophan to quinolinate, the universal de novo precursor to the pyridine ring of nicotinamide adenine dinucleotide. the enzyme requires fe2+ as a cofactor and is inactivated by 4-chloro-3-hydroxyanthranilate. had from ralstonia metallidurans was crystallized, and the structure was determined at 1.9 a resolution. the structures of ... | 2005 | 15909978 |
| gene expression analysis of six gc-rich gram-negative phytopathogens. | predicted highly expressed (phx) genes are comparatively analyzed for six gc-rich gram-negative phytopathogens, i.e., ralstonia solanacearum, agrobacterium tumefaciens, xanthomonas campestris pv. campestris (xcc), xanthomonas axonopodis pv. citri (xac), pseudomonas syringae pv. tomato, and xylella fastidiosa. enzymes involved in energy metabolism, such as atp synthase, and genes involved in tca cycle, are phx in most bacteria except x. fastidiosa, which prefers an anaerobic environment. most pat ... | 2005 | 15910748 |
| the fucose-binding lectin from ralstonia solanacearum. a new type of beta-propeller architecture formed by oligomerization and interacting with fucoside, fucosyllactose, and plant xyloglucan. | plant pathogens, like animal ones, use protein-carbohydrate interactions in their strategy for host recognition, attachment, and invasion. the bacterium ralstonia solanacearum, which is distributed worldwide and causes lethal wilt in many agricultural crops, was shown to produce a potent l-fucose-binding lectin, r. solanacearum lectin, a small protein of 90 amino acids with a tandem repeat in its amino acid sequence. in the present study, surface plasmon resonance experiments conducted on a seri ... | 2005 | 15923179 |
| transcriptional analysis of ralstonia eutropha genes related to poly-(r)-3-hydroxybutyrate homeostasis during batch fermentation. | poly-(r)-3-hydroxybutyrate (phb) homeostasis in ralstonia eutropha takes place at the interface of the cytosol and the hydrophobic phb granule. phb synthesis and degradation are therefore intimately linked to the process of granule assembly and breakdown. unraveling this time-dependent three-dimensional process requires an understanding of the kinetics of synthesis of relevant proteins. reverse transcriptase quantitative pcr and quantitative western blotting were carried out on batch cultures of ... | 2005 | 15924243 |
| very fast two-dimensional nmr spectroscopy for real-time investigation of dynamic events in proteins on the time scale of seconds. | we demonstrate for different protein samples that 2d 1h-15n correlation nmr spectra can be recorded in a few seconds of acquisition time using a new band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence experiment. this has enabled us to measure fast hydrogen-deuterium exchange rate constants along the backbone of a small globular protein fragment by real-time 2d nmr. | 2005 | 15926816 |
| a simple structured mathematical model for biopolymer (phb) production. | economic production technology for a biodegradable polymer (poly-beta-hydroxybutyrate, phb) is urgently required to replace conventional polymers, which have an inherent disadvantage of staying in the environment forever. various approaches have been applied for improving the productivity and reducing the production cost, which are considered to be the two major problems associated with industrial production of phb. one of the engineering approaches to improve phb productivity could be to design ... | 2005 | 15932263 |
| [formation of polyhydroxyalkanoates during the dual-nutrient-limited zone by ralstonia eutropha]. | polyhydroxyalkanoates (phas) are a class of polyesters biosynthesized by microorganisms (esp. ralstonia eutropha) under an unbalanced growth condition, and which are supposed to partly take the place of traditional plastics made from petroleum in the near future since they are harmless to the environment and biodegradable. organic acids (mainly butyrate, lactate, propionate and acetate) produced from anaerobic digested food wastes, industrial wastes and sewage may be used as cheap carbon sources ... | 2003 | 15969073 |
| [construction of recombinant escherichia coli strains producing poly (4-hydroxybutyric acid) homopolyester from glucose]. | the aim of this study is to construct recombinant escherichia coli strains capable of producing poly(4-hydroxybutyric acid) homopolyester from glucose as sole carbon source. a glutamate: succinate semialdehyde transaminase gene from escherichia coli, a glutamate decarboxylase gene from e. coli, and a 4-hydroxybutyrate dehydrogenase gene from ralstonia eutropha were cloned by pcr and assembled onto the plasmid pksse5.3 which haboured the pha synthase gene from ralstonia eutropha and 4-hydroxybuty ... | 2005 | 15989231 |
| erecta receptor-like kinase and heterotrimeric g protein from arabidopsis are required for resistance to the necrotrophic fungus plectosphaerella cucumerina. | arabidopsis resistance to the necrotrophic fungus plectosphaerella cucumerina is complex and depends on the ethylene, jasmonic acid and salicylic acid signaling pathways. a quantitative trait loci (qtl) analysis of resistance to this fungus was performed using two populations of recombinant inbred lines. three loci qrp1-qrp3 (for quantitative resistance to plectosphaerella) were identified and mapped on chromosome 2 (qrp1 and qrp2) and 5 (qrp3). qrp1, the locus showing the strongest effect, was ... | 2005 | 15998304 |
| use of pcr analyses to define the distribution of ralstonia species recovered from patients with cystic fibrosis. | two new pcr assays (for ralstonia species and ralstonia respiraculi), together with previously published pcr assays, were used to assess ralstonia isolates recovered from 111 cystic fibrosis patients. ralstonia mannitolilytica accounted for 46% of isolates, while r. respiraculi and ralstonia pickettii accounted for 19% and 18%, respectively. ralstonia basilensis and ralstonia metallidurans, species not previously recovered from human samples, were also identified. | 2005 | 16000479 |
| changes in race-specific virulence in pseudomonas syringae pv. phaseolicola are associated with a chimeric transposable element and rare deletion events in a plasmid-borne pathogenicity island. | virulence for bean and soybean is determined by effector genes in a plasmid-borne pathogenicity island (pai) in race 7 strain 1449b of pseudomonas syringae pv. phaseolicola. one of the effector genes, avrpphf, confers either pathogenicity, virulence, or avirulence depending on the plant host and is absent from races 2, 3, 4, 6, and 8 of this pathogen. analysis of cosmid clones and comparison of dna sequences showed that the absence of avrpphf from strain 1448a is due to deletion of a continuous ... | 2005 | 16000789 |
| enzymatic degradation processes of poly[(r)-3-hydroxybutyric acid] and poly[(r)-3-hydroxybutyric acid-co-(r)-3-hydroxyvaleric acid] single crystals revealed by atomic force microscopy: effects of molecular weight and second-monomer composition on erosion rates. | enzymatic degradation processes of poly[(r)-3-hydroxybutyric acid] (p(3hb)) and poly[(r)-3-hydroxybutyric acid-co-(r)-3-hydroxyvaleric acid] (p(3hb-co-3hv)) single crystals in the presence of phb depolymerase from ralstonia pickettii t1 were studied by real-time and static atomic force microscopy (afm) observations. fibril-like crystals were generated along the long axis of single crystals during the enzymatic degradation, and then the dimensions of fibril-like crystals were analyzed quantitativ ... | 2005 | 16004439 |
| dynamic adsorption behavior of poly(3-hydroxybutyrate) depolymerase onto polyester surface investigated by qcm and afm. | time-dependent adsorption behavior of poly(3-hydroxybutyrate) (phb) depolymerase from ralstonia pickettiit1 on a polyester surface was studied by complementary techniques of quarts crystal microbalance (qcm) and atomic force microscopy (afm). amorphous poly(l-lactide) (plla) thin films were used as adsorption substrates. effects of enzyme concentration on adsorption onto the plla surface were determined time-dependently by qcm. adsorption of phb depolymerase took place immediately after replacem ... | 2005 | 16004448 |
| enhancement of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production in the transgenic arabidopsis thaliana by the in vitro evolved highly active mutants of polyhydroxyalkanoate (pha) synthase from aeromonas caviae. | in this study, the enhancement of photosynthetic pha production was achieved using the highly active mutants of pha synthase created by the in vitro evolutionally techniques. the wild-type and mutated pha synthase genes from aeromonas caviae were introduced into arabidopsis thaliana together with the nadph-dependent acetoacetyl-coa reductase gene from ralstonia eutropha. expression of the highly active mutated pha synthase genes, n149s and d171g, led to an 8-10-fold increase in pha content in th ... | 2005 | 16004454 |
| a simple solid phase assay for the detection of 2,4-d in soil. | contaminated soils are usually characterized using chemical analyses. however, these do not assess the bioavailability of pollutants, a factor which may be important in estimating the risks associated with contamination. thus there is a need to support chemical analyses with information on biological effects to determine the potential risks a pollutant may pose in the soil. although bacterial bioreporters have been used to detect the presence of contaminants in soils, in general these studies ha ... | 2005 | 16009273 |
| novel intracellular 3-hydroxybutyrate-oligomer hydrolase in wautersia eutropha h16. | wautersia eutropha h16 (formerly ralstonia eutropha) mobilizes intracellularly accumulated poly(3-hydroxybutyrate) (phb) with intracellular poly(3-hydroxybutyrate) depolymerases. in this study, a novel intracellular 3-hydroxybutyrate-oligomer hydrolase (phazc) gene was cloned and overexpressed in escherichia coli. then phazc was purified and characterized. immunoblot analysis with polyclonal antiserum against phazc revealed that most phazc is present in the cytosolic fraction and a small amount ... | 2005 | 16030206 |
| amino acids in positions 48, 52, and 73 differentiate the substrate specificities of the highly homologous chlorocatechol 1,2-dioxygenases cbna and tcbc. | chlorocatechol 1,2-dioxygenase (ccd) is the first-step enzyme of the chlorocatechol ortho-cleavage pathway, which plays a central role in the degradation of various chloroaromatic compounds. two ccds, cbna from the 3-chlorobenzoate-degrader ralstonia eutropha nh9 and tcbc from the 1,2,4-trichlorobenzene-degrader pseudomonas sp. strain p51, are highly homologous, having only 12 different amino acid residues out of identical lengths of 251 amino acids. but cbna and tcbc are different in substrate ... | 2005 | 16030237 |
| comparison of biomérieux api 20ne and remel rapid nf plus, identification systems of type strains of ralstonia pickettii. | a : comparison of two commercial miniaturized rapid systems for the identification of ralstonia pickettii strains. | 2005 | 16033510 |
| pulsed field gel electrophoresis and random amplified polymorphic dna molecular characterization of ralstonia pickettii isolates from patients with nosocomial central venous catheter related bacteremia. | over a period of 18 months 3 clusters of central venous catheter-related ralstonia pickettii bacteremia occurred in 3 different units of the same hospital. in order to investigate the relatedness of the clinical isolates we studied 15 strains using pulsed-field gel electrophoresis (pfge) and randomly amplified polymorphic dna (rapd) techniques. the combined analysis of the results obtained by these two methods led us to conclude that all the patients except one were infected by a single clone co ... | 2005 | 16035259 |
| use of a reverse micelle system for study of oligomeric structure of nad+-reducing hydrogenase from ralstonia eutropha h16. | inclusion of an oligomeric enzyme, nad+-dependent hydrogenase from the hydrogen-oxidizing bacterium ralstonia eutropha, into a system of reverse micelles of different sizes resulted in its dissociation into catalytically active heterodimers and subunits, which were characterized in reactions with various substrates. it was found that: 1) the native tetrameric form of this enzyme catalyzes all types of studied reactions; 2) hydrogenase dimer, hoxhy, is a minimal structural unit catalyzing hydroge ... | 2005 | 16038606 |
| application of spectrofluorometry to the prediction of phb concentrations in a fed-batch process. | on-line estimation of biopolymer production during fermentation would be a useful adjunct to the development of strategies for process control and optimization. this study examined the applicability of spectrofluorometry, along with other on-line measurements, for the prediction of poly-beta-hydroxybutyric acid (phb) concentrations in a high-cell density fed-batch fermentation of ralstonia eutropha. models previously used for modelling phb evolution with time are not sufficiently accurate for si ... | 2005 | 16047168 |
| cesium desorption from illite as affected by exudates from rhizosphere bacteria. | biogeochemical processes in the rhizosphere can significantly alter interactions between contaminants and soil minerals. in this study, several strains of bacteria that exude aluminum (al)-chelating compounds were isolated from the rhizosphere of crested wheatgrass (agropyron desertorum) collected from the idaho national laboratory (inl). we examined the effects of exudates from bacteria in the genera bacillus, ralstonia, and enterobacter on cesium (cs) desorption from illite. exudates from thes ... | 2005 | 16047787 |
| site-directed saturation mutagenesis at residue f420 and recombination with another beneficial mutation of ralstonia eutropha polyhydroxyalkanoate synthase. | the f420s substitution enhances the specific activity of ralstonia eutropha pha synthase (phacre). we have now carried out site-directed saturation mutagenesis of f420 of phacre and, amongst the f420 mutants, the f420s mutant gave the highest poly(3-hydroxybutyrate) (phb) content. in vitro activity assay showed that the f420s enzyme had a significant decrease in its lag phase compared to that of the wild-type enzyme. enhancement of phb accumulation was achieved by combination of the f420s mutati ... | 2005 | 16049738 |
| the structure of the ni-fe site in the isolated hoxc subunit of the hydrogen-sensing hydrogenase from ralstonia eutropha. | the regulatory ni-fe hydrogenase (rh) from ralstonia eutropha which forms a [hoxbc]2 complex functions as a hydrogen sensor under aerobic conditions. we have studied a novel strep-tag isolate of the rh large subunit, hoxc(st), which lacks the fe-s clusters of hoxb, allowing for structure determination of the catalytic site by x-ray absorption spectroscopy both at the ni and, for the first time, also at the fe k-edge. this technique, together with fourier-transform infrared spectroscopy, revealed ... | 2005 | 16051223 |
| internal mass transfer effect on biodegradation of phenol by ca-alginate immobilized ralstonia eutropha. | phenol biodegradation by free and ca-alginate immobilized ralstonia eutropha was performed in batch system. optimum initial ph and temperature were determined as 7 and 30 degrees c, respectively for free cells, while a wide ph and temperature range were obtained for immobilized cells. phenol had a strong inhibitory effect on the microbial growth and haldane model was used to describe the substrate inhibition. model parameters were determined as mumax=0.89 h(-1), ks=55.11 mg dm(-3) and ki=257.94 ... | 2005 | 16051433 |
| hydrogen sensing by enzyme-catalyzed electrochemical detection. | hydrogen (h2) is a possible future alternative to current fossil-based transportation fuels; however, its lower explosive limit in air requires a reliable sensor to detect leaks wherever h2 is produced, stored, or used. most current h2 sensors employ palladium or its alloy as the sensing element, featuring high operating temperature and limited selectivity. in this study, we report using soluble hydrogenase (sh) of aerobic beta-proteobacterium ralstonia eutropha strain h16 to accomplish ambient, ... | 2005 | 16053311 |
| a model system for [nife] hydrogenase maturation studies: purification of an active site-containing hydrogenase large subunit without small subunit. | the large subunit hoxc of the h2-sensing [nife] hydrogenase from ralstonia eutropha was purified without its small subunit. two forms of hoxc were identified. both forms contained iron but only substoichiometric amounts of nickel. one form was a homodimer of hoxc whereas the second also contained the ni-fe site maturation proteins hypc and hypb. despite the presence of the ni-fe active site in some of the proteins, both forms, which lack the fe-s clusters normally present in hydrogenases, cannot ... | 2005 | 16061234 |
| phenol degradation and toxicity assessment upon biostimulation to an indigenous rhizobium ralstonia taiwanensis. | this study provides a first attempt from a toxicological perspective to put forward, in general terms and explanations, combined toxic interactions and biostimulation strategy upon nutrient medium to ralstonia taiwanensis for bioremediation. dose-response analysis clearly revealed that most of the supplemented nutrients tested (except for gluconic acid) synergistically interact with chronic toxicity to phenol, especially at low doses. acute toxicity based upon adaptation lag is a more appropriat ... | 2005 | 16080687 |
| [use of 16s rrna gene sequencing for identification of "pseudomonas-like" isolates from sputum of patients with cystic fibrosis]. | since nonfermenting, gram negative bacilli recovered from patients with cystic fibrosis could be misidentified with phenotypic procedures, we used partial 16s ribosomal rna gene (16s gene) sequencing to identify these "pseudomonas-like" isolates. 473 isolates were recovered from 66 patients in 2003. sequencing was used to identify 29 (from 24 patients) of the 473 isolates, showing unclear results with routine tests. pcr with specific primers was carried out to amplify a 995 bp fragment, which wa ... | 2005 | 16081224 |
| burkholderia and emerging pathogens in cystic fibrosis. | persons with cystic fibrosis (cf) are susceptible to respiratory tract infection with a variety of bacterial species. among these are several species in the genus burkholderia (including members of the b. cepacia complex, b. gladioli, and b. pseudomallei), stenotrophomonas maltophilia, achromobacter ( alcaligenes) xylosoxidans, certain ralstonia species, and species within the new genus pandoraea. enterobacteriaceae and several other rather unusual or novel species also can be found. many of the ... | 2003 | 16088584 |
| transmembrane transcriptional control (surface signalling) of the escherichia coli fec type. | the ferric citrate transport system of escherichia coli is the first example of a transcription initiation mechanism that starts at the cell surface. the inducer, ferric citrate, binds to an outer membrane transport protein, and without further transport elicits a signal that is transmitted across the outer membrane, the periplasm, and the cytoplasmic membrane into the cytoplasm. signal transfer across the three subcellular compartments is mediated by the outer membrane transport protein that in ... | 2004 | 16102597 |
| isotopic fractionation indicates anaerobic monochlorobenzene biodegradation. | the concentration and isotopic composition of monochlorobenzene (mcb) was monitored in the plume of an anaerobic, contaminated aquifer in bitterfeld, germany. an enrichment in the carbon isotopic composition of more than 4 delta units was found at the fringes of the plume relative to the center (-26.5 %), suggesting the occurrence of in situ biodegradation of mcb. a similar enrichment was measured in a detailed cross-section of the plume and in depth-specific samples obtained in a multilevel sam ... | 2005 | 16117106 |
| [ralstonia pickettii osteomyelitis of the trapezium]. | an immunocompromised 29-year-old man presented with a ralstonia pickettii osteomyelitis affecting the trapezium bone. the patient underwent two surgical debridement stages, including trapezectomy and long-term drainage. the type of the contaminant organism and the trapezium localization make this observation atypical. | 2005 | 16121624 |
| the active component in the flax-retting system of the zygomycete rhizopus oryzae sb is a family 28 polygalacturonase. | the zygomycete rhizopus oryzae sb is a very efficient organism for retting of flax, the initial microbiological step in the process of making linen. an extracellular polygalacturonase, when isolated could perform retting, and therefore probably is the key component in the retting system of r. oryzae. this was purified and characterized. the purified enzyme has a molecular mass of 37,436 da from mass spectrometric determination, an isoelectric point of 8.4, and has non-methylated polygalacturonic ... | 2005 | 16133102 |
| occurrence and expression of tricarboxylate synthases in ralstonia eutropha. | 2-methylcitrate synthase (2-mcs1) and citrate synthase (cs) of ralstonia eutropha strain h16 were separated by affinity chromatography and analyzed for their substrate specificities. 2-mcs1 used not only the primary substrate propionyl-coa but also acetyl-coa and, at a low rate, even butyryl-coa and valeryl-coa for condensation with oxaloacetate. the km values for propionyl-coa and acetyl-coa were 0.061 or 0.35 mm, respectively. this enzyme is therefore a competitor for acetyl-coa during biosynt ... | 2006 | 16133321 |
| a single amino acid insertion in the wrky domain of the arabidopsis tir-nbs-lrr-wrky-type disease resistance protein slh1 (sensitive to low humidity 1) causes activation of defense responses and hypersensitive cell death. | in this study we characterized the sensitive to low humidity 1 (slh1) mutant of arabidopsis ecotype no-0 which exhibits normal growth on agar plate medium but which on transfer to soil shows growth arrest and development of necrotic lesions. cdna microarray hybridization and rna gel blot analysis revealed that genes associated with activation of disease resistance were upregulated in the slh1 mutants in response to conditions of low humidity. furthermore, the slh1 mutants accumulate callose, aut ... | 2005 | 16146526 |
| characterization of a resistance-nodulation-cell division transporter system associated with the syr-syp genomic island of pseudomonas syringae pv. syringae. | a tripartite resistance-nodulation-cell division (rnd) transporter system, called the pseabc efflux system, was identified at the left border of the syr-syp genomic island of pseudomonas syringae pv. syringae strain b301d. the pseabc efflux system was located within a 5.7-kb operon that encodes an outer membrane protein (psea), a periplasmic membrane fusion protein (pseb), and an rnd-type cytoplasmic membrane protein (psec). the pseabc efflux system exhibited amino acid homology to a putative rn ... | 2005 | 16151087 |
| plasmid donor affects host range of promiscuous incp-1beta plasmid pb10 in an activated-sludge microbial community. | horizontal transfer of multiresistance plasmids in the environment contributes to the growing problem of drug-resistant pathogens. even though the plasmid host cell is the primary environment in which the plasmid functions, possible effects of the plasmid donor on the range of bacteria to which plasmids spread in microbial communities have not been investigated. in this study we show that the host range of a broad-host-range plasmid within an activated-sludge microbial community was influenced b ... | 2005 | 16151119 |
| isolation of ralstonia solanacearum hrpb constitutive mutants and secretion analysis of hrpb-regulated gene products that share homology with known type iii effectors and enzymes. | the hrp type iii secretion system (ttss) is essential for the pathogenicity of the gram-negative plant pathogen ralstonia solanacearum. to examine the secretion of type iii effector proteins via the hrp ttss, a screen was done of mutants constitutively expressing the hrpb gene, which encodes an arac-type transcriptional activator for the hrp regulon. a mutant was isolated that in an hrp-inducing medium expresses several hrpb-regulated genes 4.9-83-fold higher than the wild-type. r. solanacearum ... | 2005 | 16151200 |
| atomic force microscopic observation of in vitro polymerized poly[(r)-3-hydroxybutyrate]: insight into possible mechanism of granule formation. | atomic force microscopy (afm) was used to study the formation and growth of poly[(r)-3-hydroxybutyrate] (phb) structures formed in the enzymatic polymerization of (r)-3-hydroxybutyryl coenzyme a [(r)-3-hbcoa] in vitro. poly(3-hydroxyalkanoate) (pha) synthase (phac(re)) from ralstonia eutropha, a class i synthase, was purified by one-step purification and then used for in vitro reactions. before the reaction, phac(re) molecules were deposited on highly oriented pyrolytic graphite (hopg) and obser ... | 2005 | 16153105 |
| hydrogen independent expression of hupsl genes in thiocapsa roseopersicina bbs. | the expression of many membrane bound [nife] hydrogenases is regulated by their substrate molecule, hydrogen. the hupsl hydrogenase, encoded in the hupslcdhir operon, probably plays a role in hydrogen recycling in the phototrophic purple bacterium, thiocapsa roseopersicina bbs. rpon, coding for sigma factor 54, was shown to be important for expression, suggesting a regulated biosynthsis from the hup gene cluster. the response regulator gene, hupr, has been identified in the hup operon and expres ... | 2005 | 16156799 |
| control of expression of a periplasmic nickel efflux pump by periplasmic nickel concentrations. | there is accumulating evidence that transenvelope efflux pumps of the resistance, nodulation, cell division protein family (rnd) are excreting toxic substances from the periplasm across the outer membrane directly to the outside. this would mean that resistance of gram-negative bacteria to organic toxins and heavy metals is in fact a two-step process: one set of resistance factors control the concentration of a toxic substance in the periplasm, another one that in the cytoplasm. efficient peripl ... | 2005 | 16158236 |
| requirements for heterologous production of a complex metalloenzyme: the membrane-bound [nife] hydrogenase. | by taking advantage of the tightly clustered genes for the membrane-bound [nife] hydrogenase of ralstonia eutropha h16, broad-host-range recombinant plasmids were constructed carrying the entire membrane-bound hydrogenase (mbh) operon encompassing 21 genes. we demonstrate that the complex mbh biosynthetic apparatus is actively produced in hydrogenase-free hosts yielding fully assembled and functional mbh protein. | 2005 | 16159796 |
| genome-wide analysis of gene expression in ralstonia solanacearum reveals that the hrpb gene acts as a regulatory switch controlling multiple virulence pathways. | a 70-mer oligonucleotide-based dna microarray covering 5,074 of the 5,120 predicted genes from ralstonia solanacearum has been generated and used to investigate the repertoire of genes that are under the control of the transcription activator hrpb, which governs pathogenicity in this plant pathogenic bacterium. this study identified 143 hrpb up-regulated genes and 50 hrpb down-regulated genes. in addition to extending the repertoire of type iii effector proteins with 26 new candidates, this work ... | 2005 | 16167764 |
| cell cycle synchronization of cupriavidus necator by continuous phasing measured via flow cytometry. | the continuous phasing technique was successfully used to obtain a high degree of cell cycle synchrony in cultures of the model organism ralstonia eutropha jmp 134 (today reclassified into cupriavidus necator). the responses of the organism were evaluated with flow cytometric determinations of dna contents and cell size (by fluorescence and forward scatter measurements, respectively, after staining with the dna-binding dye 4',6-diamidino-2'-phenylindole, dapi), and cell concentration, after stai ... | 2005 | 16180241 |
| isolation and antifungal activity of 4-phenyl-3-butenoic acid from streptomyces koyangensis strain vk-a60. | an antifungal compound was isolated from the culture broth of streptomyces koyangensis strain vk-a60 using various chromatographic procedures. on the basis of the high-resolution ei-mass and 1h and 13c nmr data, the compound was identified as 4-phenyl-3-butenoic acid. colletotrichum orbiculare, magnaporthe grisea, and pythium ultimum were most sensitive to 4-phenyl-3-butenoic acid. strong inhibitory effects of 4-phenyl-3-butenoic acid also were found against pectobacterium carotovorum subsp. car ... | 2005 | 16190619 |
| first report of an arabinose-specific fungal lectin. | to date, arabinose-binding lectins have been reported only from the human opportunistic pathogen pseudomonas aeruginosa, the plant aggressive pathogen ralstonia solanacearum, and the sponge pellina semitubulosa. an arabinose-binding lectin with mitogenic activity toward splenocytes and a high specific hemagglutinating activity was isolated in the present study from a wild discomycete mushroom, peziza sylvestris. the maximal mitogenic activity was induced by a lectin concentration of 8 microm. th ... | 2005 | 16199005 |