Publications

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
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
competitive ability and survival in soil of pseudomonas strain 679-2, a dominant, nonobligate bacterial predator of bacteria.	a copper-resistant, nonobligate, bacterial predator of bacteria was isolated from soil. it was a pseudomonas species, designated strain 679-2. it attacked most other nonobligate bacterial predators and hence could control their predatory and other activities in nature. it also inhibited various fungi. it attached to prey cells and produced a toxic, copper-related, growth initiation factor like that produced by cupriavidus necator. in addition, it produced a second, novel compound that was both a ...	1992	16348631
protozoan response to the addition of bacterial predators and other bacteria to soil.	representatives of several categories of bacteria were added to soil to determine which of them might elicit responses from the soil protozoa. the various categories were nonobligate bacterial predators of bacteria, prey bacteria for these predators, indigenous bacteria that are normally present in high numbers in soil, and non-native bacteria that often find their way in large numbers into soil. the soil was incubated and the responses of the indigenous protozoa were determined by most-probable ...	1989	16347983
response in soil of cupriavidus necator and other copper-resistant bacterial predators of bacteria to addition of water, soluble nutrients, various bacterial species, or bacillus thuringiensis spores and crystals.	soil was incubated with various species of bacteria, bacillus subtilis, or bacillus thuringiensis spores and crystals. these were added to serve as potential prey for indigenous, copper-resistant, nonobligate bacterial predators of bacteria in the soil. alternatively, the soil was incubated with soluble nutrients or water only to cause potential indigenous prey cells to multiply so the predator cells would multiply. all of these incubation procedures caused excessive multiplication of some gram- ...	1988	16347727