| structural analysis of the fds operon encoding the nad+-linked formate dehydrogenase of ralstonia eutropha. | the fdsgbacd operon encoding the four subunits of the nad+-reducing formate dehydrogenase of ralstonia eutropha h16 was cloned and sequenced. sequence comparisons indicated a high resemblance of fdsa (alpha-subunit) to the catalytic subunits of formate dehydrogenases containing a molybdenum (or tungsten) cofactor. the nh2-terminal region (residues 1-240) of fdsa, lacking in formate dehydrogenases not linked to nad(p)+, exhibited considerable similarity to that of nuog of the nadh:ubiquinone oxid ... | 1998 | 9756865 |
| duplication of hyp genes involved in maturation of [nife] hydrogenases in alcaligenes eutrophus h16. | alcaligenes eutrophus h16 harbors seven hyp genes (hypa, b, f, c, d, e, and x) as part of the hydrogenase gene cluster on megaplasmid phg1. here we demonstrate that three of the hyp genes (hypa, b, and f) are duplicated in a. eutrophus, which explains the lack of a phenotypic change in single-site mutants impaired in one of the two copies. mutants with lesions in both copies showed clear alterations in hydrogenase activities. deletions in hypf1 and hypf2 completely abolished activities of the so ... | 1998 | 9799289 |
| hoxx (hypx) is a functional member of the alcaligenes eutrophus hyp gene cluster. | the role of hoxx in hydrogenase biosynthesis of alcaligenes eutrophus h16 was re-examined. the previously characterized hoxx deletion mutant hf344 and a newly constructed second hoxx mutant carrying a smaller in-frame deletion were studied. the second mutant was impaired in the activity of both the soluble and the membrane-bound hydrogenase. the two hydrogenase activities were reduced by approximately 50% due to delayed processing of the active-site-containing large subunits, while hydrogenase g ... | 1998 | 9799290 |
| protein organization on the pha inclusion cytoplasmic boundary. | polyhydroxyalkanoate (pha) cellular inclusions consist of polyesters, phospholipids, and proteins. both the polymerase and the depolymerase enzymes are active components of the structure. recently, proteins associated with these inclusions have been described in a number of bacterial species. in order to further clarify the structure and function of these proteins in relation to polymer inclusions, ultrastructural studies of isolated polymer inclusions were initiated. the surface boundary charac ... | 1998 | 9821672 |
| formation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by pha synthase from ralstonia eutropha. | the acetoacetyl-coa reductase and the polyhydroxyalkanoate (pha) synthase from ralstonia eutropha (formerly alcaligenes eutrophus) were expressed in escherichia coli, klebsiella aerogenes, and pha-negative mutants of r. eutropha and pseudomonas putida. while expression in e. coli strains resulted in the accumulation of poly(3-hydroxybutyrate) [phb], strains of r. eutropha, p. putida and k. aerogenes accumulated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [poly(3hb-co-3hhx)] when even chain fat ... | 1998 | 9821674 |
| characterization of the active site of a hydrogen sensor from alcaligenes eutrophus. | a third hydrogenase was recently identified in the proteobacterium alcaligenes eutrophus as a constituent of a novel h2-sensing multicomponent regulatory system. this regulatory hydrogenase (rh) has been overexpressed in cells deficient in both the nad+-reducing [nife]-hydrogenase and the membrane-bound [nife]-hydrogenase. epr, ftir and activity studies of membrane-free extracts revealed that the rh has an active site much like that of standard [nife]-hydrogenases, i.e. a ni-fe site with two cn- ... | 1998 | 9827551 |
| aqueous release and purification of poly(beta-hydroxybutyrate) from escherichia coli. | the poly(beta-hydroxybutyrate) (phb) biosynthetic genes of ralstonia eutropha that are organized in a single operon (phacab) have been cloned in escherichia coli, where the expression of the genes in the wild-type pha operon from plasmid ptz18u-phb leads to the formation of 50-80% phb/celldry mass when the cells are grown in luria-bertani medium supplemented with 1% glucose (w/v). in combination with the phacab genes, expression of cloned lysis gene e of bacteriophage phix174 from plasmid psh2 h ... | 1998 | 9828460 |
| cloning and molecular analysis of the poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyalkanoate) biosynthesis genes in pseudomonas sp. strain 61-3. | two types of polyhydroxyalkanoate (pha) biosynthesis gene loci (phb and pha) of pseudomonas sp. strain 61-3, which produces a blend of poly(3-hydroxybutyrate) [p(3hb)] homopolymer and a random copolymer (poly(3-hydroxybutyrate-co-3-hydroxyalkanoate) [p(3hb-co-3ha]) consisting of 3ha units of 4 to 12 carbon atoms, were cloned and analyzed at the molecular level. in the phb locus, three open reading frames encoding polyhydroxybutyrate (phb) synthase (phbcps), beta-ketothiolase (phbaps), and nadph- ... | 1998 | 9851987 |
| heterologous phi x174 gene e-expression in ralstonia eutropha: e-mediated lysis is not restricted to gamma-subclass of proteobacteria. | e-lysis of ralstonia eutropha h16, which belongs to the beta-subclass, was undertaken to verify whether transmembrane tunnel formation is possible in bacteria which do not belong to the enterobacteriaceae. for this purpose, a new gene e expression plasmid, pkg12, with two origins of replication, oriv and orit, from plasmid prp4, chloramphenicol and kanamycin resistance genes and a casette composed of lambda ci857 and lambda pr gene e was constructed. temperature upshift of r. eutropha h16 (pkg12 ... | 1998 | 9866870 |
| screening of xenobiotic compounds degrading microorganisms using biosensor techniques. | a screening device based on microorganisms immobilised onto a clark-type oxygen electrode was used to monitor the potential of these microorganisms for the degradation and detection of xenobiotic compounds especially their chlorinated derivatives. the sensitivity and specificity of various species of pseudomonas, sphinomonas, ralstonia, rhodococcus were characterised in relation to xenobiotic compounds by using biosensor techniques. the following groups of xenobiotics were subjects of investigat ... | 1998 | 9880928 |
| tn4371: a modular structure encoding a phage-like integrase, a pseudomonas-like catabolic pathway, and rp4/ti-like transfer functions. | tn4371 is a 55-kb catabolic transposon originally isolated from ralstonia eutropha a5 that encodes enzymes catalyzing the complete degradation of biphenyl. unlike previously described transposons encoding similar genes for aromatic compound degradation. tn4371 carries a phage-like degradation, tn4371 integrase gene and rp4/ti-like transfer genes. tn4371 transposition involves an excision/integration process and, consistent with this site-specific recombination mechanism, the ends of the element ... | 1999 | 9887305 |
| the chlorocatechol-catabolic transposon tn5707 of alcaligenes eutrophus nh9, carrying a gene cluster highly homologous to that in the 1,2,4-trichlorobenzene-degrading bacterium pseudomonas sp. strain p51, confers the ability to grow on 3-chlorobenzoate. | alcaligenes eutrophus (ralstonia eutropha) nh9, isolated in japan, utilizes 3-chlorobenzoate as its sole source of carbon and energy. sequencing of the relevant region of plasmid penh91 from strain nh9 revealed that the genes for the catabolic enzymes were homologous to the genes of the modified ortho-cleavage pathway. the genes from strain nh9 (cbnr-abcd) showed the highest homology (89 to 100% identity at the nucleotide level) to the tcbr-cdef genes on plasmid pp51 of the 1,2,4-trichlorobenzen ... | 1999 | 9925607 |
| analysis of 4-phosphopantetheinylation of polyhydroxybutyrate synthase from ralstonia eutropha: generation of beta-alanine auxotrophic tn5 mutants and cloning of the pand gene region. | the postulated posttranslational modification of the polyhydroxybutyrate (pha) synthase from ralstonia eutropha by 4-phosphopantetheine was investigated. four beta-alanine auxotrophic tn5-induced mutants of r. eutropha hf39 were isolated, and two insertions were mapped in an open reading frame with strong similarity to the pand gene from escherichia coli, encoding l-aspartate-1-decarboxylase (ec 4.1.1.15), whereas two other insertions were mapped in an open reading frame (orf) with strong simila ... | 1999 | 10049372 |
| 3-hydroxylaminophenol mutase from ralstonia eutropha jmp134 catalyzes a bamberger rearrangement. | 3-hydroxylaminophenol mutase from ralstonia eutropha jmp134 is involved in the degradative pathway of 3-nitrophenol, in which it catalyzes the conversion of 3-hydroxylaminophenol to aminohydroquinone. to show that the reaction was really catalyzed by a single enzyme without the release of intermediates, the corresponding protein was purified to apparent homogeneity from an extract of cells grown on 3-nitrophenol as the nitrogen source and succinate as the carbon and energy source. 3-hydroxylamin ... | 1999 | 10049374 |
| metabolic engineering of poly(3-hydroxyalkanoates): from dna to plastic. | poly(3-hydroxyalkanoates) (phas) are a class of microbially produced polyesters that have potential applications as conventional plastics, specifically thermoplastic elastomers. a wealth of biological diversity in pha formation exists, with at least 100 different pha constituents and at least five different dedicated pha biosynthetic pathways. this diversity, in combination with classical microbial physiology and modern molecular biology, has now opened up this area for genetic and metabolic eng ... | 1999 | 10066830 |
| utilization of phenoxyacetic acid, by strains using either the ortho or meta cleavage of catechol during phenol degradation, after conjugal transfer of tfda, the gene encoding a 2,4-dichlorophenoxyacetic acid/2-oxoglutarate dioxygenase. | the degradation of recalcitrant pollutants in contaminated soils and waters could be facilitated by broadening the degradative capabilities of indigenous microbes by the conjugal transfer of catabolic genes. the feasibility of establishing bacterial populations that degrade phenoxyacetic acid by conjugal transfer of tfda, the gene encoding 2,4-dichlorophenoxyacetic acid/2-oxoglutarate dioxygenase, to phenol-degrading strains of pseudomonas and ralstonia was examined. the mobilizable plasmid pkjs ... | 1999 | 10091327 |
| metabolic modeling of polyhydroxybutyrate biosynthesis. | a mathematical model describing intracellular polyhydroxybutyrate (phb) synthesis in alcaligenes eutrophus has been constructed. the model allows investigation of issues such as the existence of rate-limiting enzymatic steps, possible regulatory mechanisms in phb synthesis, and the effects different types of rate expressions have on model behavior. simulations with the model indicate that activities of all phb pathway enzymes influence overall phb flux and that no single enzymatic step can easil ... | 1998 | 10099235 |
| efficient and economical recovery of poly(3-hydroxybutyrate) from recombinant escherichia coli by simple digestion with chemicals. | a simple method for the recovery of microbial poly(3-hydroxybutyrate) [p(3hb)] from recombinant escherichia coli harboring the ralstonia eutropha pha biosynthesis genes was developed. various acids (hcl, h2so4), alkalies (naoh, koh, and nh4oh), and surfactants (dioctylsulfosuccinate sodium salt [aot], hexadecyltrimethylammonium bromide [ctab], sodium dodecylsulfate [sds], polyoxyethylene-p-tert-octylphenol [triton x-100], and polyoxyethylene(20)sorbitan monolaurate [tween 20]) were examined for ... | 1999 | 10099563 |
| cdc group iv c-2: a new ralstonia species close to ralstonia eutropha. | cdc group iv c-2, an environmental gram-negative bacillus recently proposed for inclusion in the genus ralstonia, has been isolated in several human infections. biochemical characterization and 16s ribosomal dna (rdna) sequencing with phylogenetic analysis were used to characterize eight clinical isolates and four type strains. other typing tools, such as pulsed-field gel electrophoresis (pfge) and randomly amplified polymorphic dna (rapd) analysis, were also used. pfge typing of clinical isolat ... | 1999 | 10325323 |
| chemoselective nitro group reduction and reductive dechlorination initiate degradation of 2-chloro-5-nitrophenol by ralstonia eutropha jmp134. | ralstonia eutropha jmp134 utilizes 2-chloro-5-nitrophenol as a sole source of nitrogen, carbon, and energy. the initial steps for degradation of 2-chloro-5-nitrophenol are analogous to those of 3-nitrophenol degradation in r. eutropha jmp134. 2-chloro-5-nitrophenol is initially reduced to 2-chloro-5-hydroxylaminophenol, which is subject to an enzymatic bamberger rearrangement yielding 2-amino-5-chlorohydroquinone. the chlorine of 2-amino-5-chlorohydroquinone is removed by a reductive mechanism, ... | 1999 | 10347008 |
| earthworm egg capsules as vectors for the environmental introduction of biodegradative bacteria. | earthworm egg capsules (cocoons) may acquire bacteria from the environment in which they are produced. we found that ralstonia eutropha (pjp4) can be recovered from eisenia fetida cocoons formed in soil inoculated with this bacterium. plasmid pjp4 contains the genes necessary for 2,4-dichlorophenoxyacetic acid (2,4-d) and 2, 4-dichlorophenol (2,4-dcp) degradation. in this study we determined that the presence of r. eutropha (pjp4) within the developing earthworm cocoon can influence the degradat ... | 1999 | 10347016 |
| substrate specificities of the chloromuconate cycloisomerases from pseudomonas sp. b13, ralstonia eutropha jmp134 and pseudomonas sp. p51. | the chloromuconate cycloisomerase of pseudomonas sp. b13 was purified from 3-chlorobenzoate-grown wild-type cells while the chloromuconate cycloisomerases of ralstonia eutropha jmp134 (pjp4) and pseudomonas sp. p51 (pp51) were purified from escherichia coli strains expressing the corresponding gene. kinetic studies were performed with various chloro-, fluoro-, and methylsubstituted cis,cis-muconates. 2,4-dichloro-cis,cis-muconate proved to be the best substrate for all three chloromuconate cyclo ... | 1999 | 10390818 |
| a novel sinorhizobium meliloti operon encodes an alpha-glucosidase and a periplasmic-binding-protein-dependent transport system for alpha-glucosides. | the most abundant carbon source transported into legume root nodules is photosynthetically produced sucrose, yet the importance of its metabolism by rhizobia in planta is not yet known. to identify genes involved in sucrose uptake and hydrolysis, we screened a sinorhizobium meliloti genomic library and discovered a segment of s. meliloti dna which allows ralstonia eutropha to grow on the alpha-glucosides sucrose, maltose, and trehalose. tn5 mutagenesis localized the required genes to a 6.8-kb re ... | 1999 | 10400573 |
| mutational analysis of the cbb operon (co2 assimilation) promoter of ralstonia eutropha. | pl promoters direct the transcription of the duplicated cbb operons from the facultative chemoautotroph ralstonia eutropha h16. the operons encode most enzymes of the calvin-benson-bassham carbon reduction cycle required for co2 assimilation. their transcription depends on the activator protein cbbr. structure-function relationships in the cloned chromosomal promoter region were analyzed by site-directed mutagenesis. pl was altered in its presumed hexameric -35 and/or -10 box or in the spacer re ... | 1999 | 10400596 |
| dynamics of multigene expression during catabolic adaptation of ralstonia eutropha jmp134 (pjp4) to the herbicide 2, 4-dichlorophenoxyacetate. | ralstonia eutropha jmp134 carries a 22 kb dna region on plasmid pjp4 necessary for the degradation of 2,4-d (2,4-dichlorophenoxyacetate). in this study, expression of the 2,4-d pathway genes (designated tfd ) upon exposure to different concentrations of 2,4-d was measured at a detailed timescale in chemostat-grown r. eutropha cultures. a sharp increase in mrna levels for tfda, tfdcdef-b, tfddiiciieiifii-bii and tfdk was detected between 2 and 13 min after exposure to 2,4-d. this response time wa ... | 1999 | 10411755 |
| pha production, from bacteria to plants. | the genes encoding the polyhydroxyalkanoate (pha) biosynthetic pathway in ralstonia eutropha (3-ketothiolase, phaa or bktb; acetoacetyl-coa reductase, phab; and pha synthase, phac) were engineered for plant plastid targeting and expressed using leaf (e35s) or seed-specific (7s or lesquerella hydroxylase) promoters in arabidopsis and brassica. pha yields in homozygous transformants were 12-13% of the dry mass in homozygous arabidopsis plants and approximately 7% of the seed weight in seeds from h ... | 1999 | 10416678 |
| a megaplasmid-borne anaerobic ribonucleotide reductase in alcaligenes eutrophus h16. | the conjugative 450-kb megaplasmid phg1 is essential for the anaerobic growth of alcaligenes eutrophus h16 in the presence of nitrate as the terminal electron acceptor. we identified two megaplasmid-borne genes (nrdd and nrdg) which are indispensable under these conditions. sequence alignment identified significant similarity of the 76.2-kda gene product nrdd and the 30.9-kda gene product nrdg with anaerobic class iii ribonucleotide reductases and their corresponding activases. deletion of nrdd ... | 1999 | 10438763 |
| cloning and characterization of a sulfonate/alpha-ketoglutarate dioxygenase from saccharomyces cerevisiae. | the saccharomyces cerevisiae open reading frame yll057c is predicted to encode a gene product with 31.5% amino acid sequence identity to escherichia coli taurine/alpha-ketoglutarate dioxygenase and 27% identity to ralstonia eutropha tfda, a herbicide-degrading enzyme. purified recombinant yeast protein is shown to be an fe(ii)-dependent sulfonate/alpha-ketoglutarate dioxygenase. although taurine is a poor substrate, a variety of other sulfonates are utilized, with the best natural substrates bei ... | 1999 | 10482536 |
| transcriptional activation of the chlorocatechol degradative genes of ralstonia eutropha nh9. | ralstonia eutropha (formerly alcaligenes eutrophus) nh9 degrades 3-chlorobenzoate via the modified ortho-cleavage pathway. a ca. 5.7-kb six-gene cluster is responsible for chlorocatechol degradation: the cbnabcd operon encoding the degradative enzymes (including orfx of unknown function) and the divergently transcribed cbnr gene encoding the lysr-type transcriptional regulator of the cbn operon. the cbnrab orfxcd gene cluster is nearly identical to the chlorocatechol genes (tcbrcd orfxef) of the ... | 1999 | 10542171 |
| czcd is a heavy metal ion transporter involved in regulation of heavy metal resistance in ralstonia sp. strain ch34. | the czc system of ralstonia sp. strain ch34 mediates resistance to cobalt, zinc, and cadmium through ion efflux catalyzed by the czccb(2)a cation-proton antiporter. the czcd protein is involved in the regulation of the czc system. it is a membrane-bound protein with at least four transmembrane alpha-helices and is a member of a subfamily of the cation diffusion facilitator (cdf) protein family, which occurs in all three domains of life. the deletion of czcd in a ralstonia sp. led to partially co ... | 1999 | 10559151 |
| dual control by regulatory gene fdsr of the fds operon encoding the nad+-linked formate dehydrogenase of ralstonia eutropha. | the transcriptional regulator gene fdsr was identified 150 bp upstream of the divergently oriented fdsgbacd operon encoding the soluble, nad+-linked formate dehydrogenase in the chemoautotrophic bacterium ralstonia eutropha h16. its deduced product, fdsr, displays a basal sequence similarity to the regulatory proteins of the lysr family. the carboxy-terminal domain of fdsr contains a short region that is conserved in formate dehydrogenases. deletion of fdsr revealed a dual regulatory effect of f ... | 1999 | 10564479 |
| biochemical and molecular characterization of a succinate semialdehyde dehydrogenase involved in the catabolism of 4-hydroxybutyric acid in ralstonia eutropha. | a succinate semialdehyde dehydrogenase gene (gabd) was identified to be disrupted in a transposon-induced mutant of ralstonia eutropha exhibiting the phenotype 4-hydroxybutyric acid-leaky. the native gabd gene was cloned by colony hybridization using a homologous gabd-specific dna probe. dna sequencing revealed an 1452-bp open reading frame, and the deduced amino acid sequence showed strong similarities to nadp(+)-dependent succinate semialdehyde dehydrogenases from escherichia coli, rhizobium s ... | 1999 | 10564790 |
| purification and characterization of the single-component nitric oxide reductase from ralstonia eutropha h16. | nitric oxide (no) reductase was purified from ralstonia eutropha (formerly alcaligenes eutrophus) using a two step chromatographic procedure. unlike the common no reductases, the enzyme consists of a single subunit of 75 kda which contains both high-spin and low-spin heme b, but lacks heme c. one additional iron atom, probably a ferric non-heme iron, was identified per enzyme molecule. whereas reduced cytochrome c was ineffective as electron donor, no was reduced at a specific activity of 2.3 mi ... | 1999 | 10571051 |
| feasibility study on the utilization of rubber latex effluent for producing bacterial biopolymers. | rubber latex effluent is a polluting source that has a high biochemical oxygen demand (bod). it is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. this study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber ... | 1999 | 10595441 |
| analysis of in vivo substrate specificity of the pha synthase from ralstonia eutropha: formation of novel copolyesters in recombinant escherichia coli. | in order to investigate the in vivo substrate specificity of the type i polyhydroxyalkanoate (pha) synthase from ralstonia eutropha, we functionally expressed the pha synthase gene in various escherichia coli mutants affected in fatty acid beta-oxidation and the wild-type. the pha synthase gene was expressed either solely (pbhr70) or in addition to the r. eutropha genes encoding beta-ketothiolase and acetoacetyl-coenzyme a (coa) reductase comprising the entire phb operon (pbhr68) as well as in c ... | 2000 | 10612741 |
| adaptive responses of ralstonia eutropha to feast and famine conditions analysed by flow cytometry. | results obtained by flow cytometry allow conclusions to be drawn about how the physiological states of ralstsonia eutropha jmp134 are connected with survival strategies under distinct growth conditions. during both feast and famine conditions the cells were found to proceed through sharply separated phases of life. two sources of carbon and energy, one poor (0.02% phenol) and one rich (0.2% pyruvate and 0.1% yeast extract) were chosen to study the cellular responses. despite the major difference ... | 1999 | 10617338 |
| ralstonia eutropha tf93 is blocked in tat-mediated protein export. | ralstonia eutropha (formerly alcaligenes eutrophus) tf93 is pleiotropically affected in the translocation of redox enzymes synthesized with an n-terminal signal peptide bearing a twin arginine (s/t-r-r-x-f-l-k) motif. immunoblot analyses showed that the catalytic subunits of the membrane-bound [nife] hydrogenase (mbh) and the molybdenum cofactor-binding periplasmic nitrate reductase (nap) are mislocalized to the cytoplasm and to the inner membrane, respectively. moreover, physiological studies s ... | 2000 | 10633089 |
| the use of plant biotechnology for the production of biodegradable plastics. | | 2000 | 10664613 |
| regulation of the cnr cobalt and nickel resistance determinant from ralstonia sp. strain ch34. | ralstonia sp. strain ch34 is resistant to nickel and cobalt cations. resistance is mediated by the cnr determinant located on plasmid pmol28. the cnr genes are organized in two clusters, cnryxh and cnrcba. as revealed by reverse transcriptase pcr and primer extension, transcription from these operons is initiated from promoters located upstream of the cnry and cnrc genes. these two promoters exhibit conserved sequences at the -10 (ccgtata) and -35 (craggggrag) regions. the cnrh gene product, whi ... | 2000 | 10671463 |
| regulation of the cnr cobalt and nickel resistance determinant of ralstonia eutropha (alcaligenes eutrophus) ch34. | the linked resistance to nickel and cobalt of ralstonia eutropha-like strain ch34 (alcaligenes eutrophus ch34) is encoded by the cnr operon, which is localized on the megaplasmid pmol28. the regulatory genes cnryxh have been cloned, overexpressed, and purified in escherichia coli. cnry fractionated as a 10.7-kda protein in in vitro translation assays. cnrx, a periplasmic protein of 16.5 kda, was overproduced and purified as a histidine-tagged fusion protein in e. coli. his-cnrx was found to poss ... | 2000 | 10671464 |
| calorimetrically recognized maximum yield of poly-3-hydroxybutyrate (phb) continuously synthesized from toxic substrates. | the broader usage of poly-beta-hydroxybutyrate (phb), for instance as bulk plastics, calls for cheap raw materials and greater overall process efficiency. the bacterial synthesis is generally induced and promoted by the limitation of growth via nitrogen, oxygen or phosphate depletion with the simultaneous excess and higher concentration of the carbon substrate. consequently, toxic substrates have been considered unsuitable for phb synthesis. nevertheless, a single-stage continuous process for pr ... | 2000 | 10682283 |
| production of polyhydroxyalkanoic acids by ralstonia eutropha and pseudomonas oleovorans from an oil remaining from biotechnological rhamnose production. | screening experiments identified several bacteria which were able to use residual oil from biotechnological rhamnose production as a carbon source for growth. ralstonia eutropha h16 and pseudomonas oleovorans were able to use this waste material as the sole carbon source for growth and for the accumulation of polyhydroxyalkanoic acids (pha). r. eutropha and p. oleovorans accumulated pha amounting to 41.3% and 38.9%, respectively, of the cell dry mass, when these strains were cultivated in minera ... | 2000 | 10709978 |
| role of tfdc(i)d(i)e(i)f(i) and tfdd(ii)c(ii)e(ii)f(ii) gene modules in catabolism of 3-chlorobenzoate by ralstonia eutropha jmp134(pjp4). | the enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow ralstonia eutropha jmp134(pjp4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-cb). there are two gene modules located in plasmid pjp4, tfdc(i)d(i)e(i)f(i) (module i) and tfdd(ii)c(ii)e(ii)f(ii) (module ii), putatively encoding these enzymes. to assess the role of both tfd modules in the degradation of chloroaro ... | 2000 | 10742248 |
| factors affecting the freeze-fracture morphology of in vivo polyhydroxyalkanoate granules. | interesting morphologies were observed when comamonas acidovorans containing polyhydroxyalkanoates (pha) of various compositions was freeze-fractured at temperatures far below the glass transition temperatures of pha. in vivo granules of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) comparatively showed the most ductility, and could be stretched extensively. contrary to the uniform needle-type deformation shown by the poly(3-hydroxybutyrate) homopolymer when fractured at -110 degrees c, copolymer ... | 2000 | 10779866 |
| the h(2) sensor of ralstonia eutropha is a member of the subclass of regulatory [nife] hydrogenases. | two energy-generating hydrogenases enable the aerobic hydrogen bacterium ralstonia eutropha (formerly alcaligenes eutrophus) to use molecular hydrogen as the sole energy source. the complex synthesis of the nickel-iron-containing enzymes has to be efficiently regulated in response to h(2), which is available in low amounts in aerobic environments. h(2) sensing in r. eutropha is achieved by a hydrogenase-like protein which controls the hydrogenase gene expression in concert with a two-component r ... | 2000 | 10781538 |
| biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant bacteria expressing the pha synthase gene phac1 from pseudomonas sp. 61-3. | pseudomonas sp. 61-3 accumulated a blend of poly(3-hydroxybutyrate) [p(3hb)] homopolymer and a random copolymer consisting of 3-hydroxyalkanoate (3ha) units of 4-12 carbon atoms. the genes encoding beta-ketothiolase (phba(re)) and nadph-dependent acetoacetyl-coa reductase (phbb(re)) from ralstonia eutropha were expressed under the control of promoters for pseudomonas sp. 61-3 pha locus or r. eutropha phb operon together with phac1(ps) gene (pha synthase 1 gene) from pseudomonas sp. 61-3 in pha-n ... | 2000 | 10803895 |
| sequence of pha synthase gene from two strains of rhodospirillum rubrum and in vivo substrate specificity of four pha synthases across two heterologous expression systems. | a 3.0-kb genomic fragment has been isolated from rhodospirillum rubrum (atcc 25903) that contains an open reading frame (orf) with strong homology to other known polyhydroxyalkanoate (pha) synthase genes. this orf has lower homology to the r. rubrum strain ha pha synthase than would be expected within the same species. we have conducted a series of heterologous expression studies evaluating the in vivo substrate specificity of pha synthase genes from rhodobacter sphaeroides, ralstonia eutropha ( ... | 2000 | 10803898 |
| microbes with a mettle for bioremediation. | | 2000 | 10835594 |
| engineering a mouse metallothionein on the cell surface of ralstonia eutropha ch34 for immobilization of heavy metals in soil. | here we describe targeting of the mouse metallothionein i (mt) protein to the cell surface of the heavy metal-tolerant ralstonia eutropha (formerly alcaligenes eutrophus) ch34 strain, which is adapted to thrive in soils highly polluted with metal ions. dna sequences encoding mt were fused to the autotransporter beta-domain of the iga protease of neisseria gonorrhoeae, which targeted the hybrid protein toward the bacterial outer membrane. the translocation, surface display, and functionality of t ... | 2000 | 10835606 |
| construction of recombinant escherichia coli strains for polyhydroxybutyrate production using soy waste as nutrient. | construction and comparison of recombinant escherichia coli strains harboring the polyhydroxybutyrate (phb) operon from ralstonia eutropha using vectors possessing different promotors, as well as the production of phb from soy waste by the recombinant strain, are reported. the lac promotor was the most efficient on expression of the phb operon among the three promotors studied: i.e., lac promotor, t7 promotor and the normal sigma 70 promotor. the pks/phb was the most efficient plasmid for phb op ... | 2000 | 10849804 |
| phosphotransacetylase as a key factor in biological production of polyhydroxybutyrate. | phosphotransacetylase (pta) catalyzes the reversible conversion of acetyl-coenzyme a (coa) to acetyl phosphate. polyhydroxybutyrate (phb) synthase and accumulation were compared between a pta-deficient mutant and the wild-type escherichia coli, which were transformed with pae100, coding for 3-ketothiolase, nadph-dependent acetoacetyl-coa reductase, and phb synthase from ralstonia eutropha. during the growth period, phb synthase activity in the pta-deficient mutant was lower than that in the wild ... | 2000 | 10849856 |
| deletions of mob and tra pjp4 transfer functions after mating of ralstonia eutropha jmp134 (pjp4) with escherichia coli harboring f'::tn10. | one-tenth of escherichia coli transconjugants resulting from the transfer of the catabolic plasmid pjp4 from ralstonia eutropha jmp134 to e. coli xl1blue, contained pjp4 derivatives with deletions (approximately 15-30 kb). the occurrence of these deletions is probably associated with the presence of tn10 in the recipient. dna endonuclease restriction analysis of the pjp4 deletion derivatives showed the absence of sphi and ecori fragments previously reported to hybridize with incp tra dna probes. ... | 2000 | 10872085 |
| genetic diversity of ralstonia solanacearum as assessed by pcr-rflp of the hrp gene region, aflp and 16s rrna sequence analysis, and identification of an african subdivision. | the genetic diversity among strains in a worldwide collection of ralstonia solanacearum, causal agent of bacterial wilt, was assessed by using three different molecular methods. pcr-rflp analysis of the hrp gene region was extended from previous studies to include additional strains and showed that five amplicons were produced not only with all r. solanacearum strains but also with strains of the closely related bacteria pseudomonas syzygii and the blood disease bacterium (bdb). however, the thr ... | 2000 | 10878132 |
| [studies on fermentation conditions for the accumulation of poly-beta-hydroxybutyrate in alcaligenes eutrophus]. | the results of the cultivation of alcaligenes eutrophus showed that nitrogen limitation or exhaustion could stimulate the substantial accumulation of phb. but the exhaustion of nitrogen source in phb formation period would result in the rapid drop of phb synthetic rate. oxygen limitation could also stimulate the formation of phb, but the content of phb in the cell was much less than that in case of nitrogen controlled conditions. obvious influences were observed on phb fermentation when ammonia ... | 2000 | 10883288 |
| characterization of a second tfd gene cluster for chlorophenol and chlorocatechol metabolism on plasmid pjp4 in ralstonia eutropha jmp134(pjp4). | within the 5.9-kb dna region between the tfdr and tfdk genes on the 2,4-dichlorophenoxyacetic acid (2,4-d) catabolic plasmid pjp4 from ralstonia eutropha jmp134, we identified five open reading frames (orfs) with significant homology to the genes for chlorocatechol and chlorophenol metabolism (tfdcdef and tfdb) already present elsewhere on pjp4. the five orfs were organized and assigned as follows: tfdd(ii)c(ii)e(ii)f(ii) and tfdb(ii) (in short, the tfd(ii) cluster), by analogy to tfdcdef and tf ... | 2000 | 10894723 |
| comparison of 2,4-dichlorophenoxyacetic acid degradation and plasmid transfer in soil resulting from bioaugmentation with two different pjp4 donors. | a pilot field study was conducted to assess the impact of bioaugmentation with two plasmid pjp4-bearing microorganisms: the natural host, ralstonia eutropha jmp134, and a laboratory-generated strain amenable to donor counterselection, escherichia coli d11. the r. eutropha strain contained chromosomal genes necessary for mineralization of 2,4-dichlorophenoxyacetic acid (2,4-d), while the e. coli strain did not. the soil system was contaminated with 2,4-d alone or was cocontaminated with 2,4-d and ... | 2000 | 10919798 |
| kinetics of biodegradation of p-nitrophenol by different bacteria. | three bacterial species, i.e., ralstonia sp. sj98, arthrobacter protophormiae rkj100, and burkholderia cepacia rkj200, have been examined for their efficiency and kinetics behavior toward pnp degradation. all the three bacteria utilized pnp as the sole source of carbon, nitrogen, and energy. the rates of radiolabeled [u-(14)c]pnp degradation by all the bacteria were higher in the nitrogen-free medium compared to the medium with nitrogen. the apparent k(m) values of pnp degradation by sj98, rkj10 ... | 2000 | 10924328 |
| recovery of poly(3-hydroxybutyrate) from coagulated ralstonia eutropha using a chemical digestion method. | for economic recovery of poly(3-hydroxybutyrate) (phb) from culture broths of ralstonia eutropha containing phb, al-based and fe-based coagulants were used in the pretreatment step. the coagulated cells were then separated by centrifugation, and phb was extracted by chemical digestion with a sodium hypochlorite/chloroform dispersion solution. the practical upper limits of dosage were found to be 1, 500 mg-al/l and 1,000 mg-fe/l, respectively, for al- and fe-based coagulants. when the harvested c ... | 2000 | 10933846 |
| phosphoenolpyruvate is a signal metabolite in transcriptional control of the cbb co2 fixation operons in ralstonia eutropha. | the two highly homologous cbb operons of the facultative chemoautotroph ralstonia eutropha h16 encode most enzymes of the calvin-benson-bassham carbon reduction cycle. their transcriptional regulation was investigated both in vitro and in vivo to identify a metabolic signal involved in this process. for this purpose an in vitro transcription system employing the dna-dependent rna polymerase purified from r. eutropha was established. the enzyme from escherichia coli was also used in verifying com ... | 2000 | 10937440 |
| a broad-host-range plasmid for isolating mobile genetic elements in gram-negative bacteria. | plasmid pgbg1 was constructed to isolate mobile genetic elements in a wide variety of gram-negative bacteria. the mutation target, carried on a broad-host-range vector, allows positive selection for tetracycline resistance. in tests using several gram-negative bacteria we could detect transposition events of either insertion sequences or transposons. a new insertion sequence (is) element was identified in ralstonia eutropha. | 2000 | 10964631 |
| starvation improves survival of bacteria introduced into activated sludge. | a phenol-degrading bacterium, ralstonia eutropha e2, was grown in luria-bertani (lb) medium or in an inorganic medium (called mp) supplemented with phenol and harvested at the late-exponential-growth phase. phenol-acclimated activated sludge was inoculated with the e2 cells immediately after harvest or after starvation in mp for 2 or 7 days. the densities of the e2 populations in the activated sludge were then monitored by quantitative pcr. the e2 cells grown on phenol and starved for 2 days (p- ... | 2000 | 10966407 |
| factors influencing the biosorption of gadolinium by micro-organisms and its mobilisation from sand. | the present work was devoted to the study of the biosorption capacities of various microbial species (bacillus subtilis, pseudomonas aeruginosa, ralstonia metallidurans ch34 previously alcaligenes eutrophus ch34, mycobacterium smegmatis, saccharomyces cerevisiae) for ions of the lanthanide gadolinium (gd3+). the uptake by sand of this element was also measured. saturation curves and scatchard models were established for all biosorbants used in this work. the results enabled us to determine the b ... | 2000 | 10968643 |
| degradation of 2,4,6-trichlorophenol via chlorohydroxyquinol in ralstonia eutropha jmp134 and jmp222. | the aim of this work was to study the catabolic pathway of the pollutant 2,4,6-trichlorophenol in ralstonia eutropha jmp134. 2,6-dichlorohydroquinone was detected as transient intermediate. enzymatic transformations of 6-chlorohydroxyquinol to 2-chloromaleylacetate, and of this compound to maleylacetate were detected in crude extracts. therefore, the degradation of 2,4,6-trichlorophenol proceeded through an hydroxyquinol pathway, different from the other chloroaromatic pathways reported in this ... | 2000 | 10986670 |
| mobilization of poly(3-hydroxybutyrate) in ralstonia eutropha. | ralstonia eutropha h16 degraded (mobilized) previously accumulated poly(3-hydroxybutyrate) (phb) in the absence of an exogenous carbon source and used the degradation products for growth and survival. isolated native phb granules of mobilized r. eutropha cells released 3-hydroxybutyrate (3hb) at a threefold higher rate than did control granules of nonmobilized bacteria. no 3hb was released by native phb granules of recombinant escherichia coli expressing the phb biosynthetic genes. native phb gr ... | 2000 | 11004196 |
| a bioluminescent whole-cell reporter for detection of 2, 4-dichlorophenoxyacetic acid and 2,4-dichlorophenol in soil. | a bioreporter was made containing a tfdrp(dii)-luxcdabe fusion in a modified mini-tn5 construct. when it was introduced into the chromosome of ralstonia eutropha jmp134, the resulting strain, jmp134-32, produced a sensitive bioluminescent response to 2, 4-dichlorophenoxyacetic acid (2,4-d) at concentrations of 2.0 microm to 5.0 mm. this response was linear (r(2) = 0.9825) in the range of 2.0 microm to 1.1 x 10(2) microm. saturation occurred at higher concentrations, with maximal bioluminescence ... | 2000 | 11010925 |
| evidence that ralstonia eutropha (alcaligenes eutrophus) contains a functional homologue of the ralstonia solanacearum phc cell density sensing system. | in the phytopathogen ralstonia (pseudomonas) solanacearum, control of many virulence genes is partly mediated by the phc cell density sensing system. phc uses a novel self-produced signal molecule [3-hydroxypalmitic acid methyl ester (3-oh pame)], an atypical two-component system (phcs/phcr), and a lysr-type activator (phca) to regulate a reversible switching between two different physiological states. while phc is present in most r. solanacearum strains, it is apparently absent from other pseud ... | 2000 | 11069661 |
| a novel no-responding regulator controls the reduction of nitric oxide in ralstonia eutropha. | ralstonia eutropha h16 mediates the reduction of nitric oxide (no) to nitrous oxide (n2o) with two isofunctional single component membrane-bound no reductases (norb1 and norb2). this reaction is integrated into the denitrification pathway that involves the successive reduction of nitrate to dinitrogen. the norb1 gene is co-transcribed with nora1 from a sigma54 (rpon)-dependent promoter, located upstream of nora1. with the aid of nora1'-lacz transcriptional fusions and the generation of regulator ... | 2000 | 11069685 |
| cloning of an intracellular poly[d(-)-3-hydroxybutyrate] depolymerase gene from ralstonia eutropha h16 and characterization of the gene product. | an intracellular poly[d(-)-3-hydroxybutyrate] (phb) depolymerase gene (phaz) has been cloned from ralstonia eutropha h16 by the shotgun method, sequenced, and characterized. nucleotide sequence analysis of a 2.3-kbp dna fragment revealed an open reading frame of 1,260 bp, encoding a protein of 419 amino acids with a predicted molecular mass of 47,316 da. the crude extract of escherichia coli containing the phb depolymerase gene digested artificial amorphous phb granules and released mainly oligo ... | 2001 | 11114905 |
| simultaneous detection of gfp-marked moraxella sp. g21r and lux-marked ralstonia eutrophas h850lr using most-probable-number method. | the green fluorescent protein encoded by gfp gene and the luminescent protein encoded by luxab genes were used as markers to detect p-nitrophenol (pnp)-degrading moraxella sp. g21r and polychlorinated biphenyl (pcb)-degrading ralstonia eutrophas h850lr cells, respectively, in mixed liquid cultures and in soil samples using a most-probable-number (mpn) assay. population estimates for both gfp-marked g21r and lux-marked h850lr by using mpn assays were similar to viable colony counts. the mpn assay ... | 2000 | 11121604 |
| occurrence of tn4371-related mobile elements and sequences in (chloro)biphenyl-degrading bacteria. | tn4371, a 55-kb transposable element involved in the degradation and biphenyl or 4-chlorobiphenyl identified in ralstonia eutropha a5, displays a modular structure including a phage-like integrase gene (int), a pseudomonas-like (chloro)biphenyl catabolic gene cluster (bph), and rp4- and ti-plasmid-like transfer genes (trb) (c. merlin, d. springael, and a. toussaint, plasmid 41:40-54, 1999). southern blot hybridization was used to examine the presence of different regions of tn4371 in a collectio ... | 2001 | 11133426 |
| ralstonia paucula (formerly cdc group iv c-2): unsuccessful strain differentiation with pcr-based methods, study of the 16s-23s spacer of the rrna operon, and comparison with other ralstonia species (r. eutropha, r. pickettii, r. gilardii, and r. solanacearum). | ralstonia paucula (formerly cdc group iv c-2) can cause serious human infections. confronted in 1995 with five cases of nosocomial bacteremia, we found that pulsed-field gel electrophoresis could not distinguish between the isolates and that randomly amplified polymorphic dna analysis was poorly discriminatory. in this study, we used pcr-ribotyping and pcr-restriction fragment length polymorphism analysis of the spacer 16s-23s ribosomal dna (rdna); both methods were unable to differentiate r. pa ... | 2001 | 11136807 |
| bioremediation of polychlorinated biphenyl-contaminated soil using carvone and surfactant-grown bacteria. | partial bioremediation of polychlorinated biphenyl (pcb)-contaminated soil was achieved by repeated applications of pcb-degrading bacteria and a surfactant applied 34 times over an 18-week period. two bacterial species, arthrobacter sp. strain b1b and ralstonia eutrophus h850, were induced for pcb degradation by carvone and salicylic acid, respectively, and were complementary for the removal of different pcb congeners. a variety of application strategies was examined utilizing a surfactant, sorb ... | 2000 | 11152078 |
| mobilization of selenite by ralstonia metallidurans ch34. | ralstonia metallidurans ch34 (formerly alcaligenes eutrophus ch34) is a soil bacterium characteristic of metal-contaminated biotopes, as it is able to grow in the presence of a variety of heavy metals. r. metallidurans ch34 is reported now to resist up to 6 mm selenite and to reduce selenite to elemental red selenium as shown by extended x-ray absorption fine-structure analysis. growth kinetics analysis suggests an adaptation of the cells to the selenite stress during the lag-phase period. depen ... | 2001 | 11157242 |
| nickel-resistance-based minitransposons: new tools for genetic manipulation of environmental bacteria. | the ncc and nre nickel resistance determinants from ralstonia eutropha-like strain 31a were used to construct mini-tn5 transposons. broad host expression of nickel resistance was observed for the nre minitransposons in members of the alpha, beta, and gamma subclasses of the proteobacteria, while the ncc minitransposons expressed nickel resistance only in r. eutropha-like strains. | 2001 | 11157282 |
| identification of a new class of biopolymer: bacterial synthesis of a sulfur-containing polymer with thioester linkages. | this is the first report on the biosynthesis of a hitherto unknown, sulfur-containing polyester and also the first report on a bacterial polymer containing sulfur in the backbone. the gram-negative polyhydroxyalkanoate (pha)-accumulating bacterium ralstonia eutropha synthesized a copolymer of 3-hydroxybutyrate and 3-mercaptopropionate, poly(3hb-co-3mp), when 3-mercaptopropionic acid or 3,3'-thiodipropionic acid was provided as carbon source in addition to fructose or gluconic acid under nitrogen ... | 2001 | 11160796 |
| mechanistic studies on class i polyhydroxybutyrate (phb) synthase from ralstonia eutropha: class i and iii synthases share a similar catalytic mechanism. | the class i and iii polyhydroxybutyrate (phb) synthases from ralstonia eutropha and chromatium vinosum, respectively, catalyze the polymerization of beta-hydroxybutyryl-coenzyme a (hbcoa) to generate phb. these synthases have different molecular weights, subunit composition, and kinetic properties. recent studies with the c. vinosum synthase suggested that it is structurally homologous to bacterial lipases and allowed identification of active site residues important for catalysis [jia, y., kappo ... | 2001 | 11170423 |
| catalytic and molecular properties of the quinohemoprotein tetrahydrofurfuryl alcohol dehydrogenase from ralstonia eutropha strain bo. | the quinohemoprotein tetrahydrofurfuryl alcohol dehydrogenase (thfa-dh) from ralstonia eutropha strain bo was investigated for its catalytic properties. the apparent k(cat)/k(m) and k(i) values for several substrates were determined using ferricyanide as an artificial electron acceptor. the highest catalytic efficiency was obtained with n-pentanol exhibiting a k(cat)/k(m) value of 788 x 10(4) m(-1) s(-1). the enzyme showed substrate inhibition kinetics for most of the alcohols and aldehydes inve ... | 2001 | 11222593 |
| modification of the aggregation behaviour of the environmental ralstonia eutropha-like strain ae815 is reflected by both surface hydrophobicity and amplified fragment length polymorphism (aflp) patterns. | after inoculation of the plasmid-free non-aggregative ralstonia eutropha-like strain ae815 in activated sludge, followed by reisolation on a selective medium, a mutant strain a3 was obtained, which was characterized by an autoaggregative behaviour. strain a3 had also acquired an incp1 plasmid, plme1, co-aggregated with yeast cells when co-cultured, and stained better with congo red than did the ae815 strain. contact angle measurements showed that the mutant strain was considerably more hydrophob ... | 2000 | 11243262 |
| new insight into the role of the phap phasin of ralstonia eutropha in promoting synthesis of polyhydroxybutyrate. | phasins are proteins that are proposed to play important roles in polyhydroxyalkanoate synthesis and granule formation. here the phasin phap of ralstonia eutropha has been analyzed with regard to its role in the synthesis of polyhydroxybutyrate (phb). purified recombinant phap, antibodies against phap, and an r. eutropha phap deletion strain have been generated for this analysis. studies with the phap deletion strain show that phap must accumulate to high levels in order to play its normal role ... | 2001 | 11244085 |
| the h2 sensor of ralstonia eutropha. biochemical characteristics, spectroscopic properties, and its interaction with a histidine protein kinase. | previous genetic studies have revealed a multicomponent signal transduction chain, consisting of an h(2) sensor, a histidine protein kinase, and a response regulator, which controls hydrogenase gene transcription in the proteobacterium ralstonia eutropha. in this study, we isolated the h(2) sensor and demonstrated that the purified protein forms a complex with the histidine protein kinase. biochemical and spectroscopic analysis revealed that the h(2) sensor is a cytoplasmic [nife]-hydrogenase wi ... | 2001 | 11278570 |
| cloning and expression of a ralstonia eutropha hf39 gene mediating indigo formation in escherichia coli. | on complex medium escherichia coli strains carrying hybrid plasmid pbec/ee:11.0, pskbec/be:9.0, pskbec/pp:3.3, or pskbec/pp:2.4 harboring genomic dna of ralstonia eutropha hf39 produced a blue pigment characterized as indigo by several chemical and spectroscopic methods. a 1,251-bp open reading frame (bec) was cloned and sequenced. the deduced amino acid sequence of bec showed only weak similarities to short-chain acyl-coenzyme a dehydrogenases, and the gene product catalyzed formation of indoxy ... | 2001 | 11282658 |
| analysis of mutational effects of a polyhydroxybutyrate (phb) polymerase on bacterial phb accumulation using an in vivo assay system. | polymerase is a central enzyme involved in the biosynthesis of polyhydroxybutyrate (phb), a well-known bacterial biodegradable polyester. in this study, we have established an in vivo assay system to analyze mutational effects of ralstonia eutropha polymerase (termed phbc(re)) on the level of phb accumulation in recombinant strains of escherichia coli. this in vitro evolution system consists of a polymerase chain reaction-mediated random mutagenesis and two assay procedures, a plate assay using ... | 2001 | 11325555 |
| heterologous expression of the acyl-acyl carrier protein thioesterase gene from the plant umbellularia californica mediates polyhydroxyalkanoate biosynthesis in recombinant escherichia coli. | the acyl-acyl carrier protein (acp) thioesterase cdna from the plant umbellularia californica was functionally expressed in various recombinant escherichia coli strains in order to establish a new metabolic route toward medium-chain-length polyhydroxyalkanoate (pha(mcl)) biosynthesis from non-related carbon sources. coexpression of the pha synthase genes from ralstonia eutropha and pseudomonas aeruginosa, or only the pha synthase gene from p. aeruginosa, respectively, showed pha(mcl) accumulatio ... | 2001 | 11330715 |
| a calorimetrically based method to convert toxic compounds into poly-3-hydroxybutyrate and to determine the efficiency and velocity of conversion. | a fed-batch method for converting toxic substrates into poly-3-hydroxybutyrate is presented. the method involves a series of batch-growth processes, regulated by adding small amounts of carbon substrate, during the course of which the concentration of the nitrogen source decreases and controls the distribution of the substrate-carbon assimilated. the addition of carbon substrate is controlled, and the small changes that occur in the growth pattern are interpreted using high-resolution reaction c ... | 2001 | 11330720 |
| metabolic flux modeling of detoxification of acetic acid by ralstonia eutropha at slightly alkaline ph levels. | ralstonia eutropha grows on and produces polyhydroxyalkanoates (phas) from fermentation acids. acetic acid, one major organic acid from acidogenesis of organic wastes, has an inhibitory effect on the bacterium at slightly alkaline ph (6 g hac/l at ph 8). the tolerance of r. eutropha to acetate, however, was increased significantly up to 15 g/l at the slightly alkaline ph level with high cell mass concentration. a metabolic cell model with five fluxes is proposed to depict the detoxification mech ... | 2001 | 11344450 |
| a microbial biosensor to predict bioavailable nickel in soil and its transfer to plants. | ralstonia eutropha strain ae2515 was constructed and optimised to serve as a whole-cell biosensor for the detection of bioavailable concentrations of ni2+ and co2+ in soil samples. strain ae2515 is a ralstonia eutropha ch34 derivative containing pmol1550, in which the cnryxh regulatory genes are transcriptionally fused to the bioluminescent luxcdabe reporter system. strain ae2515 was standardised for its specific responses to co2+ and ni2+. the detection limits for ae2515 were 0.1 microm ni2+ an ... | 2001 | 11351758 |
| identification of two tetranuclear fes clusters on the ferredoxin-type subunit of nadh:ubiquinone oxidoreductase (complex i). | the proton-translocating nadh:ubiquinone oxidoreductase of respiratory chains (complex i) contains one flavin mononucleotide and five epr-detectable iron-sulfur clusters as redox groups. because of the number of conserved motifs typical for binding iron-sulfur clusters and the high content of iron and acid-labile sulfide of complex i preparations, it is predicted that complex i contains additional clusters which have not yet been detected by epr spectroscopy. to search for such clusters, we used ... | 2001 | 11352750 |
| 2,4-dichlorophenoxyacetate/alpha-ketoglutarate dioxygenases from burkholderia cepacia 2a and ralstonia eutropha jmp134. | 2,4-dichlorophenoxyacetate (2,4-d)/alpha-ketoglutarate (alpha-kg) dioxygenase has been purified to apparent homogeneity from burkholderia cepacia strain 2a, which utilizes 2,4-d as sole carbon source. the enzyme required ferrous ions, and was a homodimer composed of subunits having an mr of approximately 32,000. the reaction catalysed consumed one mol each of 2,4-d, alpha-kg and dioxygen, with the production of one mol each of succinate, 2,4-dichlorophenol and glyoxylate. maximum activity was ex ... | 2001 | 11368091 |
| continuous production of poly-3-hydroxybutyrate by ralstonia eutropha in a two-stage culture system. | poly-3-hydroxybutyrate (phb) is mainly accumulated by ralstonia eutropha under unbalanced growth conditions, which limits its production in batch or fed-batch modes. the continuous production of phb was investigated in a two-stage continuous culture system. the first-stage produced cell mass giving the maximal cell dry weight of 27.1 g l(-1) at 0.21 h(-1) of dilution rate. high specific cell growth rate results in the decrease of phb synthesis under glucose-limited and nitrogen-rich conditions i ... | 2001 | 11377765 |
| frankia kb5 possesses a hydrogenase immunologically related to membrane-bound. | the immunological relationship of the hydrogenase in frankia kb5 to hydrogenases in other microorganisms was investigated using antisera raised against holo-[nife]-hydrogenases isolated from alcaligenes latus, azotobacter vinelandii, ralstonia eutropha, and the small and large hydrogenase subunits from bradyrhizobium japonicum. the antisera raised against the a. latus, r. eutropha, and b. japonicum (large subunit) polypeptides were found to recognize two polypeptides, corresponding to the unproc ... | 2001 | 11381338 |
| effects of 2,2',5,5'-tetrachlorobiphenyl and biphenyl on cell membranes of ralstonia eutropha h850. | the effects of 2,2',5,5'-tetrachlorobiphenyl (tecb), a pcb congener, and biphenyl on the cytoplasmic membranes of ralstonia eutropha h850 were investigated by measuring fluorescence polarization using 1,6-diphenyl-1,3,5-hexatriene (dph) as the probe, and determining the cellular fatty acid compositions. tecb significantly affected the membrane of r. eutropha h850 cells grown on fructose by decreasing dph fluorescence polarization. in contrast, the membrane of cells grown on biphenyl showed a con ... | 2001 | 11410343 |
| accumulation of the phap phasin of ralstonia eutropha is dependent on production of polyhydroxybutyrate in cells. | polyhydroxyalkanoates (phas) are polyoxoesters that are produced by diverse bacteria and that accumulate as intracellular granules. phasins are granule-associated proteins that accumulate to high levels in strains that are producing phas. the accumulation of phasins has been proposed to be dependent on pha production, a model which is now rigorously tested for the phasin phap of ralstonia eutropha. r. eutropha phac pha synthase and phap phasin gene replacement strains were constructed. the strai ... | 2001 | 11418562 |
| kinetic analysis on formation of poly(3-hydroxybutyrate) from acetic acid by ralstonia eutropha under chemically defined conditions. | batch cultures of ralstonia eutropha in chemically defined media with acetic acid (hac) as the sole carbon source were conducted to investigate acetate utilization, formation of poly(3-hydroxybutyrate) (phb) and growth of active biomass (abm) under different carbon to nitrogen (c/n) weight ratios. the specific acetate utilization rate based on abm approached 0.16 g/g abm h(-1), which was not affected very much by the extracellular hac concentration from 1 to 5 g/l, but was affected by the c/n we ... | 2001 | 11420650 |
| dual-bioaugmentation strategy to enhance remediation of cocontaminated soil. | although metals are thought to inhibit the ability of microorganisms to degrade organic pollutants, several microbial mechanisms of resistance to metal are known to exist. this study examined the potential of cadmium-resistant microorganisms to reduce soluble cadmium levels to enhance degradation of 2,4-dichlorophenoxyacetic acid (2,4-d) under conditions of cocontamination. four cadmium-resistant soil microorganisms were examined in this study. resistant up to a cadmium concentration of 275 micr ... | 2001 | 11425743 |
| a physical map of the megaplasmid phg1, one of three genomic replicons in ralstonia eutropha h16. | we have used pulsed field gel electrophoresis and megabase dna techniques to investigate the basic genomic organization of ralstonia eutropha h16, and to construct a physical map of its indigenous megaplasmid phg1. this gram-negative, soil-dwelling bacterium is a facultative chemolithoautotroph and a denitrifier. in the absence of organic substrates it can grow on h2 as its sole energy source and co2 as its sole source of carbon. under anaerobic conditions it can utilize nitrate as a terminal el ... | 2001 | 11470364 |
| molecular characterization of a deletion/duplication rearrangement in tfd genes from ralstonia eutropha jmp134(pjp4) that improves growth on 3-chlorobenzoic acid but abolishes growth on 2,4-dichlorophenoxyacetic acid. | ralstonia eutropha jmp134(pjp4) is able to grow on minimal media containing the pollutants 3-chlorobenzoate (3-cb) or 2,4-dichlorophenoxyacetate (2,4-d). tfd genes from the 88 kb plasmid pjp4 encode enzymes involved in the degradation of these compounds. during growth of strain jmp134 in liquid medium containing 3-cb, a derivative strain harbouring a approximately 95 kb plasmid was isolated. this derivative, designated jmp134(pjp4-f3), had an improved ability to grow on 3-cb, but had lost the ab ... | 2001 | 11495991 |
| the methylcitric acid pathway in ralstonia eutropha: new genes identified involved in propionate metabolism. | from ralstonia eutropha hf39 null-allele mutants were created by tn5 mutagenesis and by homologous recombination which were impaired in growth on propionic acid and levulinic acid. from the molecular, physiological and enzymic analysis of these mutants it was concluded that in this bacterium propionic acid is metabolized via the methylcitric acid pathway. the genes encoding enzymes of this pathway are organized in a cluster in the order prpr, prpb, prpc, acnm, orf5 and prpd, with prpr transcribe ... | 2001 | 11495997 |
| isolation and characterization of a thermotolerant bacterium ralstonia sp. strain phs1 that degrades benzene, toluene, ethylbenzene, and o-xylene. | a thermotolerant bacterium, designated as phs1, was isolated from a hot spring in pohang, korea, on the basis of its ability to grow on benzene, toluene, ethylbenzene, and xylenes (btex) as a sole carbon source. strain phs1 is a gram-negative, rod-shaped aerobe and grows optimally at 42 degrees c and ph 7.2. according to 16 s rdna analysis, strain phs1 showed highest similarity to ralstonia eutropha (previously named alcaligenes eutrophus). unlike its closest known ralstonia species, however, st ... | 2001 | 11499943 |
| molecular characterization and heterologous expression of hypcd, the first two [nife] hydrogenase accessory genes of thermococcus litoralis. | the hypcd genes, encoding the counterparts of mesophilic proteins involved in the maturation of [nife] hydrogenases, were isolated from the hyperthermophilic archaeon thermococcus litoralis. the deduced gene products showed 30-40% identity to the corresponding mesophilic proteins. hypc and hypd were synthesized by the t7 expression system. heterologous complementation experiments were done in escherichia coli and ralstonia eutropha strains lacking functionally active hypc and hypd genes. only th ... | 2001 | 11511872 |
| hydrogen bacteria as a potential regenerative lss component and producer of ecologically clean degradable plastic. | | 1999 | 11542681 |