| active-site engineering of biphenyl dioxygenase: effect of substituted amino acids on substrate specificity and regiospecificity. | biphenyl dioxygenase (bph dox) catalyzes the initial dioxygenation step in the metabolism of biphenyl. the large subunit (bpha1) of bph dox plays a crucial role in the determination of the substrate specificity of biphenyl-related compounds including polychlorinated biphenyls (pcbs). previously, the substitution of asn at thr-376 near the active-site iron in the bpha1 of pseudomonas pseudoalcaligenes kf707 expanded the oxidation range and altered the regiospecificity of bph dox for pcbs. in this ... | 2006 | 16217654 |
| engineering a hybrid pseudomonad to acquire 3,4-dioxygenase activity for polychlorinated biphenyls. | we constructed a hybrid strain that acquired 3,4-dioxygenase activity for polychlorinated biphenyls (pcbs). this strain, kf707-d34, possessed a chimeric biphenyl dioxygenase gene, of which a portion of bpha1 (coding for a large subunit of biphenyl dioxygenase) of pseudomonas pseudoalcaligenes kf707 was replaced with that of a pcb-degrader, burkholderia cepacia lb400 by homologous recombination. kf707-d34 retained the ability to degrade 4,4'-dichlorobiphenyl via 2,3-dioxygenation in a fashion ide ... | 1999 | 16232495 |
| pleiotropic costs of niche expansion in the rna bacteriophage phi 6. | natural and experimental systems have failed to universally demonstrate a trade-off between generalism and specialism. when a trade-off does occur it is difficult to attribute its cause to antagonistic pleiotropy without dissecting the genetic basis of adaptation, and few previous experiments provide these genetic data. here we investigate the evolution of expanded host range (generalism) in the rna virus phi6, an experimental model system allowing adaptive mutations to be readily identified. we ... | 2006 | 16299384 |
| influence of inorganic nitrogen management regime on the diversity of nitrite-oxidizing bacteria in agricultural grassland soils. | to assess links between the diversity of nitrite-oxidizing bacteria (nob) in agricultural grassland soils and inorganic n fertilizer management, nob communities in fertilized and unfertilized soils were characterized by analysis of clone libraries and denaturing gradient gel electrophoresis (dgge) of 16s rrna gene fragments. previously uncharacterized nitrospira-like sequences were isolated from both long-term-fertilized and unfertilized soils, but dgge migration patterns indicated the presence ... | 2005 | 16332819 |
| metabolism of the plasticizer di-n-butylphthalate by pseudomonas pseudoalcaligenes under anaerobic conditions, with nitrate as the only electron acceptor. | the metabolism of di-n-butylphthalate by a denitrifying strain of pseudomonas pseudoalcaligenes b20b1 was studied under anaerobic conditions, with nitrate as the only electron acceptor. thin-layer chromatography and mass spectral analysis of culture extracts (20 days at 30 degrees c) showed mono-n-butylphthalate and phthalic acid as the only products, suggesting that one butanol moiety served essentially as the carbon source for growth and denitrification. n(2) and n(2)o were detected by gas chr ... | 1982 | 16346088 |
| effects of chemical speciation on the mineralization of organic compounds by microorganisms. | the mineralization of 1.0 to 100 ng each of four complexing compounds-oxalate, citrate, nitrilotriacetate (nta), and edta-per ml was tested in media prepared in accordance with equilibrium calculations by a computer program so that the h, ca, mg, fe, or al complex (chemical species) was predominant. sewage microorganisms mineralized calcium citrate more rapidly than iron, aluminum, or hydrogen citrate, and magnesium citrate was degraded slowest. aluminum, hydrogen, and iron oxalates were mineral ... | 1985 | 16346854 |
| purification and characterization of maleate hydratase from pseudomonas pseudoalcaligenes. | maleate hydratase (malease) from pseudomonas pseudoalcaligenes has been purified. the purified enzyme (98% pure) catalyzes the stereospecific addition of water to maleate and citraconate (2-methylmaleate), forming d-(+)-malate and d-(+)-citramalate, respectively. 2,3-dimethylmaleate was also a substrate for malease. the stability of the enzyme was dependent on the protein concentration and the addition of dicarboxylic acids. the purified enzyme (89 kda) consisted of two subunits (57 and 24 kda). ... | 1993 | 16349034 |
| initial reductive reactions in aerobic microbial metabolism of 2,4,6-trinitrotoluene. | because of its high electron deficiency, initial microbial transformations of 2,4,6-trinitrotoluene (tnt) are characterized by reductive rather than oxidation reactions. the reduction of the nitro groups seems to be the dominating mechanism, whereas hydrogenation of the aromatic ring, as described for picric acid, appears to be of minor importance. thus, two bacterial strains enriched with tnt as a sole source of nitrogen under aerobic conditions, a gram-negative strain called tnt-8 and a gram-p ... | 1998 | 16349484 |
| studies of the catabolic pathway of degradation of nitrobenzene by pseudomonas pseudoalcaligenes js45: removal of the amino group from 2-aminomuconic semialdehyde. | [this corrects the article on p. 4841 in vol. 63.]. | 1998 | 16349521 |
| cyanide metabolism of pseudomonas pseudoalcaligenes cect5344: role of siderophores. | cyanide is one of the most potent and toxic chemicals produced by industry. the jewelry industry of córdoba (spain) generates a wastewater (residue) that contains free cyanide, as well as large amounts of cyano-metal complexes. cyanide is highly toxic to living systems because it forms very stable complexes with transition metals that are essential for protein function. in spite of its extreme toxicity, some organisms have acquired mechanisms to avoid cyanide poisoning. the biological assimilati ... | 2006 | 16417508 |
| identification of nif genes in n2-fixing bacterial strains isolated from rice fields along the yangtze river plain. | the aim of this research was to identify nifh and nifhdkye ' genes in twenty strains of n2-fixing heterotrophic bacteria isolated from rice fields in the yangtze river plain. southern hybridization of the total dna from each strain was performed with the klebsiella pneumoniae nifhdkye ' gene probe (6.2 kb eco ri fragment from psa30) and the azospirillum brasilense nifh gene probe (0.6 kb eco ri-hin diii fragment from phu8). we found that eco ri fragments of total dna from aeromonas hydrophila hy ... | 2006 | 16463319 |
| [transformation of embryogenic calli of siberian wildrye grass (elymus sibiricus l. cv. chuancao no.2) mediated by agrobacterium]. | formation of embryogenic calli of siberian wildrye grass (elymus sibiricus l. cv. chuancao no.2) was induced from mature seeds as explants, and proliferated on ms medium containing 2,4-d 5.0 mg/l and kt 0.05 mg/l. an effective and stable callus regeneration system was established by optimizing the culture conditions (tables 1, 2 and fig.2). after the calli were subcultured 8 weeks, selected the whitish-yellow-coloured compact nodular calli that transformed with plasmid pcambia1304 carrying hygro ... | 2006 | 16477130 |
| novel partial reductive pathway for 4-chloronitrobenzene and nitrobenzene degradation in comamonas sp. strain cnb-1. | comamonas sp. strain cnb-1 grows on 4-chloronitrobenzene (4-cnb) and nitrobenzene as sole carbon and nitrogen sources. in this study, two genetic segments, cnbb-orf2-cnba and cnbr-orf1-cnbcacbdefghi, located on a newly isolated plasmid, pcnb1 (ca. 89 kb), and involved in 4-cnb/nitrobenzene degradation, were characterized. seven genes (cnba, cnbb, cnbca, cnbcb, cnbd, cnbg, and cnbh) were cloned and functionally expressed in recombinant escherichia coli, and they were identified as encoding 4-cnb ... | 2006 | 16517619 |
| oxidative pathway for the biodegradation of nitrobenzene by comamonas sp. strain js765. | previous studies have shown that the biodegradation of nitrobenzene by pseudomonas pseudoalcaligenes js45 proceeds by the reduction of nitrobenzene through nitrosobenzene and hydroxylaminobenzene, followed by rearrangement to 2-aminophenol, which then undergoes meta ring cleavage. we report here the isolation of a comamonas sp. that uses an oxidative pathway for the complete mineralization of nitrobenzene. the isolate, designated strain js765, uses nitrobenzene as a sole source of carbon, nitrog ... | 1995 | 16535050 |
| transformation of 2,4,6-trinitrotoluene by pseudomonas pseudoalcaligenes js52. | pseudomonas pseudoalcaligenes js52 grows on nitrobenzene via partial reduction of the nitro group and enzymatic rearrangement of the resultant hydroxylamine. cells and cell extracts of nitrobenzene-grown js52 catalyzed the transient formation of 4-hydroxylamino-2,6-dinitrotoluene (4hadnt), 4-amino-2,6-dinitrotoluene (4adnt), and four previously unidentified metabolites from 2,4,6-trinitrotoluene (tnt). two of the novel metabolites were identified by liquid chromatography/mass spectrometry and (s ... | 1997 | 16535610 |
| 16s rrna gene sequencing versus the api 20 ne system and the vitek 2 id-gnb card for identification of nonfermenting gram-negative bacteria in the clinical laboratory. | over a period of 26 months, we have evaluated in a prospective fashion the use of 16s rrna gene sequencing as a means of identifying clinically relevant isolates of nonfermenting gram-negative bacilli (non-pseudomonas aeruginosa) in the microbiology laboratory. the study was designed to compare phenotypic with molecular identification. results of molecular analyses were compared with two commercially available identification systems (api 20 ne, vitek 2 fluorescent card; biomérieux, marcy l'etoil ... | 2006 | 16597863 |
| the locus coding for the 3-nitrobenzoate dioxygenase of comamonas sp. strain js46 is flanked by is1071 elements and is subject to deletion and inversion events. | in comamonas sp. strain js46, 3-nitrobenzoate (3nba) is initially oxidized at the 3,4 position by a dioxygenase, which results in release of nitrite and production of protocatechuate. the locus coding for the 3nba dioxygenase (designated mnb, for m-nitrobenzoate) was mobilized from strain js46 using a plasmid capture method, cloned, and sequenced. the 3nba dioxygenase (mnba) is a member of the phthalate family of aromatic oxygenases. an open reading frame designated mnbb that codes for an nad(p) ... | 2006 | 16597970 |
| pseudomonad cyclopentadecanone monooxygenase displaying an uncommon spectrum of baeyer-villiger oxidations of cyclic ketones. | baeyer-villiger monooxygenases (bvmos) are biocatalysts that offer the prospect of high chemo-, regio-, and enantioselectivity in the organic synthesis of lactones or esters from a variety of ketones. in this study, we have cloned, sequenced, and overexpressed in escherichia coli a new bvmo, cyclopentadecanone monooxygenase (cpdb or cpdmo), originally derived from pseudomonas sp. strain hi-70. the 601-residue primary structure of cpdb revealed only 29% to 50% sequence identity to those of known ... | 2006 | 16597975 |
| steady-state kinetic characterization of evolved biphenyl dioxygenase, which acquired novel degradation ability for benzene and toluene. | biphenyl dioxygenase (bph dox) catalyzes initial oxygenation in the bacterial biphenyl degradation pathway. bph dox in pseudomonas pseudoalcaligenes kf707 is a rieske type three-component enzyme in which a large subunit (encoded by the bpha1 gene) plays an important role in the substrate specificity of bph dox. steady-state kinetic assays using purified enzyme components demonstrated that kf707 bph dox had a kcat/km of 33.1 x 10(3) (m(-1) s(-1)) for biphenyl. evolved 1072 bph dox generated by th ... | 2006 | 16636475 |
| characterization of genes involved in the initial reactions of 4-chloronitrobenzene degradation in pseudomonas putida zwl73. | the genes encoding enzymes involved in the initial reactions during degradation of 4-chloronitrobenzene (4cnb) were characterized from the 4cnb utilizer pseudomonas putida zwl73, in which a partial reductive pathway was adopted. a dna fragment containing genes coding for chloronitrobenzene nitroreductase (cnba) and hydroxylaminobenzene mutase (cnbb) were pcr-amplified and subsequently sequenced. these two genes were actively expressed in escherichia coli, and recombinant e. coli cells catalyzed ... | 2006 | 16642329 |
| assessment of toluene/biphenyl dioxygenase gene diversity in benzene-polluted soils: links between benzene biodegradation and genes similar to those encoding isopropylbenzene dioxygenases. | the pcr-single-strand conformation polymorphism (sscp) technique was used to assess the diversity and distribution of rieske nonheme iron oxygenases of the toluene/biphenyl subfamily in soil dna and bacterial isolates recovered from sites contaminated with benzene, toluene, ethylbenzene, and xylenes (btex). the central cores of genes encoding the catalytic alpha subunits were targeted, since they are responsible for the substrate specificities of these enzymes. sscp functional genotype fingerpri ... | 2006 | 16672497 |
| multiniche screening reveals the clinically relevant metallo-beta-lactamase vim-2 in pseudomonas aeruginosa far from the hospital setting: an ongoing dispersion process? | a screening study of the presence of metallo-beta-lactamases (imp and vim types and spm-1) in isolates from different nonhospital sources was conducted, and it revealed the presence of bla(vim-2), associated with the in58 class 1 integron, in two unrelated pseudomonas aeruginosa strains from aquatic habitats. the results suggest that the hospital setting was the possible origin of these bla(vim-2)-carrying strains. | 2006 | 16672526 |
| a glutathione s-transferase catalyzes the dehalogenation of inhibitory metabolites of polychlorinated biphenyls. | bphk is a glutathione s-transferase of unclear physiological function that occurs in some bacterial biphenyl catabolic (bph) pathways. we demonstrated that bphk of burkholderia xenovorans strain lb400 catalyzes the dehalogenation of 3-chloro 2-hydroxy-6-oxo-6-phenyl-2,4-dienoates (hopdas), compounds that are produced by the cometabolism of polychlorinated biphenyls (pcbs) by the bph pathway and that inhibit the pathway's hydrolase. a one-column protocol was developed to purify heterologously pro ... | 2006 | 16740949 |
| protein engineering of the 4-methyl-5-nitrocatechol monooxygenase from burkholderia sp. strain dnt for enhanced degradation of nitroaromatics. | 4-methyl-5-nitrocatechol (4m5nc) monooxygenase (dntb) from burkholderia sp. strain dnt catalyzes the second step of 2,4-dinitrotoluene degradation by converting 4m5nc to 2-hydroxy-5-methylquinone with the concomitant removal of the nitro group. dntb is a flavoprotein that has a very narrow substrate range. here, error-prone pcr was used to create variant dntb m22l/l380i, which accepts the two new substrates 4-nitrophenol (4np) and 3-methyl-4-nitrophenol (3m4np). at 300 microm of 4np, the initial ... | 2006 | 16751499 |
| expression of organophosphorus hydrolase ophc2 in pichia pastoris: purification and characterization. | organophosphorus hydrolase is able to hydrolyze phosphoester bonds and reduce the toxicity of organophosphorus compounds. in this work, recombinant organophosphorus hydrolase ophc2 was successfully produced by pichia pastoris at a high expression level (approximately 5.5 g/l) using 3 l high-cell-density fermentation. the expression level is higher than those produced in other expression systems. the results of the sds-page and the western blot analyses showed a major 36 kda polypeptide band, whi ... | 2006 | 16769224 |
| cross-regulation of biphenyl- and salicylate-catabolic genes by two regulatory systems in pseudomonas pseudoalcaligenes kf707. | pseudomonas pseudoalcaligenes kf707 grows on biphenyl and salicylate as sole sources of carbon. the biphenyl-catabolic (bph) genes are organized as bphr1a1a2(orf3)a3a4bcx0x1x2x3d, encoding the enzymes for conversion of biphenyl to acetyl coenzyme a. in this study, the salicylate-catabolic (sal) gene cluster encoding the enzymes for conversion of salicylate to acetyl coenzyme a were identified 6.6-kb downstream of the bph gene cluster along with a second regulatory gene, bphr2. both the bph and s ... | 2006 | 16788178 |
| biotreatment of waste gas containing pyridine in a biofilter. | industrial waste gas emissions containing pyridine are generated from pyridine manufacturing industries, and in industrial operations where pyridine is used as a solvent, as an intermediate for synthesis and as a catalyst for a variety of applications. pyridine has unpleasant fishy odor with an odor index of 2390 and waste gaseous emissions containing pyridine require proper treatment prior to discharge. a biofilter, packed with compost and wood chips and inoculated with pseudomonas pseudoalcali ... | 2007 | 16815008 |
| evaluation of pyrrolidonyl arylamidase for the identification of nonfermenting gram-negative rods. | to evaluate the activity of pyrrolidonyl arylamidase (pyr) for the differentiation and identification of nonfermenting gram negative rods (nfgnr), 293 isolates were tested. a 24 h culture of each test organism was prepared. from this a 108-109 cfu/ml suspension was added to 0.25 ml of sterile physiologic solution. a pyr disk was then added and the test was incubated for 30 minutes at 35-37 degrees c, at environmental atmosphere. reading was done by adding 1 drop of cinnamaldehyde reagent. strain ... | 2007 | 16822636 |
| haloalkane dehalogenase linb is responsible for beta- and delta-hexachlorocyclohexane transformation in sphingobium indicum b90a. | incubation of resting cells of sphingobium indicum b90a, sphingobium japonicum ut26, and sphingobium francense sp+ showed that they were able to transform beta- and delta-hexachlorocyclohexane (beta- and delta-hch, respectively), the most recalcitrant hexachlorocyclohexane isomers, to pentachlorocyclohexanols, but only resting cells of strain b90a could further transform the pentachlorocyclohexanol intermediates to the corresponding tetrachlorocyclohexanediols. moreover, experiments with resting ... | 2006 | 16957186 |
| application of a microfluidic reactor for screening cancer prodrug activation using silica-immobilized nitrobenzene nitroreductase. | the nitroreductase-catalyzed conversion of a strong electron-withdrawing nitro group to the corresponding electron-donating hydroxylamine is useful in a variety of biotechnological applications. activation of prodrugs for cancer treatments or antibiotic therapy are the most common applications. here, we show that a bacterial nitrobenzene nitroreductase (nbza) from pseudomonas pseudoalcaligenes js45 activates the dinitrobenzamide cancer prodrug cb1954 and the proantibiotic nitrofurazone. nbza was ... | 2006 | 16961327 |
| evidence for a tellurite-dependent generation of reactive oxygen species and absence of a tellurite-mediated adaptive response to oxidative stress in cells of pseudomonas pseudoalcaligenes kf707. | tellurite (teo3(2-)) is the most toxic and soluble oxyanion among tellurium (te) compounds. the effects of the metalloid anion on the oxidative stress response of the obligate aerobe pseudomonas pseudoalcaligenes kf707 were investigated. cells treated with sub-lethal concentrations of teo3(2-) showed neither adaptation to it nor cross-protection against oxidants such as 1,1'-4,4'-bipyridinium dichloride (paraquat, pq2+), diazenedicarboxylic acid bis-n,n-dimethylamide (diamide), tert-butyl hydrop ... | 2007 | 17013634 |
| pseudomonas segetis sp. nov., isolated from soil. | a gram-negative, aerobic bacterium, designated strain fr1439t, was isolated from the soil of dokdo in the republic of korea. the cells of strain fr1439t were catalase- and oxidase-positive, motile and rod-shaped. phylogenetic analysis of the 16s rrna gene sequence revealed that it represents a distinct line of descent within the genus pseudomonas. the levels of dna-dna relatedness between strain fr1439t and type strains of phylogenetically related species, namely pseudomonas flavescens, pseudomo ... | 2006 | 17082397 |
| multiple-level regulation of genes for protocatechuate degradation in acinetobacter baylyi includes cross-regulation. | the bacterium acinetobacter baylyi uses the branched beta-ketoadipate pathway to metabolize aromatic compounds. here, the multiple-level regulation of expression of the pca-qui operon encoding the enzymes for protocatechuate and quinate degradation was studied. it is shown that both activities of the iclr-type regulator protein pcau at the structural gene promoter pcaip, namely protocatechuate-dependent activation of pca-qui operon expression as well as repression in the absence of protocatechua ... | 2007 | 17085716 |
| multiple-level regulation of genes for protocatechuate degradation in acinetobacter baylyi includes cross-regulation. | the bacterium acinetobacter baylyi uses the branched beta-ketoadipate pathway to metabolize aromatic compounds. here, the multiple-level regulation of expression of the pca-qui operon encoding the enzymes for protocatechuate and quinate degradation was studied. it is shown that both activities of the iclr-type regulator protein pcau at the structural gene promoter pcaip, namely protocatechuate-dependent activation of pca-qui operon expression as well as repression in the absence of protocatechua ... | 2007 | 17085716 |
| the thiol:disulfide oxidoreductase dsbb mediates the oxidizing effects of the toxic metalloid tellurite (teo32-) on the plasma membrane redox system of the facultative phototroph rhodobacter capsulatus. | the highly toxic oxyanion tellurite (teo3(2-)) is a well known pro-oxidant in mammalian and bacterial cells. this work examines the effects of tellurite on the redox state of the electron transport chain of the facultative phototroph rhodobacter capsulatus, in relation to the role of the thiol:disulfide oxidoreductase dsbb. under steady-state respiration, the addition of tellurite (2.5 mm) to membrane fragments generated an extrareduction of the cytochrome pool (c- and b-type hemes); further, in ... | 2007 | 17098900 |
| the thiol:disulfide oxidoreductase dsbb mediates the oxidizing effects of the toxic metalloid tellurite (teo32-) on the plasma membrane redox system of the facultative phototroph rhodobacter capsulatus. | the highly toxic oxyanion tellurite (teo3(2-)) is a well known pro-oxidant in mammalian and bacterial cells. this work examines the effects of tellurite on the redox state of the electron transport chain of the facultative phototroph rhodobacter capsulatus, in relation to the role of the thiol:disulfide oxidoreductase dsbb. under steady-state respiration, the addition of tellurite (2.5 mm) to membrane fragments generated an extrareduction of the cytochrome pool (c- and b-type hemes); further, in ... | 2007 | 17098900 |
| family shuffling of soil dna to change the regiospecificity of burkholderia xenovorans lb400 biphenyl dioxygenase. | previous work has shown that the c-terminal portion of bpha, especially two amino acid segments designated region iii and region iv, influence the regiospecificity of the biphenyl dioxygenase (bpdo) toward 2,2'-dichlorobiphenyl (2,2'-cb). in this work, we evolved bpdo by shuffling bpha genes amplified from polychlorinated biphenyl-contaminated soil dna. sets of approximately 1-kb dna fragments were amplified with degenerate primers designed to amplify the c-terminal portion of bpha. these fragme ... | 2007 | 17142386 |
| family shuffling of soil dna to change the regiospecificity of burkholderia xenovorans lb400 biphenyl dioxygenase. | previous work has shown that the c-terminal portion of bpha, especially two amino acid segments designated region iii and region iv, influence the regiospecificity of the biphenyl dioxygenase (bpdo) toward 2,2'-dichlorobiphenyl (2,2'-cb). in this work, we evolved bpdo by shuffling bpha genes amplified from polychlorinated biphenyl-contaminated soil dna. sets of approximately 1-kb dna fragments were amplified with degenerate primers designed to amplify the c-terminal portion of bpha. these fragme ... | 2007 | 17142386 |
| a gene cluster involved in degradation of substituted salicylates via ortho cleavage in pseudomonas sp. strain mt1 encodes enzymes specifically adapted for transformation of 4-methylcatechol and 3-methylmuconate. | pseudomonas sp. strain mt1 has recently been reported to degrade 4- and 5-chlorosalicylate by a pathway assumed to consist of a patchwork of reactions comprising enzymes of the 3-oxoadipate pathway. genes encoding the initial steps in the degradation of salicylate and substituted derivatives were now localized and sequenced. one of the gene clusters characterized (sal) showed a novel gene arrangement, with sala, encoding a salicylate 1-hydroxylase, being clustered with salcd genes, encoding muco ... | 2007 | 17172348 |
| a gene cluster involved in degradation of substituted salicylates via ortho cleavage in pseudomonas sp. strain mt1 encodes enzymes specifically adapted for transformation of 4-methylcatechol and 3-methylmuconate. | pseudomonas sp. strain mt1 has recently been reported to degrade 4- and 5-chlorosalicylate by a pathway assumed to consist of a patchwork of reactions comprising enzymes of the 3-oxoadipate pathway. genes encoding the initial steps in the degradation of salicylate and substituted derivatives were now localized and sequenced. one of the gene clusters characterized (sal) showed a novel gene arrangement, with sala, encoding a salicylate 1-hydroxylase, being clustered with salcd genes, encoding muco ... | 2007 | 17172348 |
| a novel deaminase involved in chloronitrobenzene and nitrobenzene degradation with comamonas sp. strain cnb-1. | comamonas sp. strain cnb-1 degrades nitrobenzene and chloronitrobenzene via the intermediates 2-aminomuconate and 2-amino-5-chloromuconate, respectively. deamination of these two compounds results in the release of ammonia, which is used as a source of nitrogen for bacterial growth. in this study, a novel deaminase was purified from comamonas strain cnb-1, and the gene (cnbz) encoding this enzyme was cloned. the n-terminal sequence and peptide fingerprints of this deaminase were determined, and ... | 2007 | 17259310 |
| identification of diazotrophs in the culturable bacterial community associated with roots of lasiurus sindicus, a perennial grass of thar desert, india. | lasiurus sindicus is a highly nutritive, drought-tolerant, perennial grass that is endemic to the thar desert of rajasthan, india. analysis of 16s rrna coding genes of the bacterial isolates enriched in nitrogen-free semisolid medium, from the surface-sterilized roots of l. sindicus, showed predominance of gram-negative over gram-positive bacteria. according to comparative sequence analysis of 16s rdna sequence data, gram-positive bacteria with low gc content (staphylococcus warneri and bacillus ... | 2007 | 17264993 |
| high nitrogen removal from wastewater with several new aerobic bacteria isolated from diverse ecosystems. | three new bacteria hs-03, hs-043 and hs-047 isolated from different ecosystems were found capable of aerobic denitrification. the potential application of these strains in wastewater treatment under aerobic conditions was investigated. these three bacteria all presented high nitrogen removal from wastewater that more than 98% of 10 mmol/l nitrate could be removed in 12-24 h by adding cheap external carbon source and low concentration of iron as well as molybdate. the mechanism at molecular level ... | 2006 | 17294651 |
| bacterial toxicity of potassium tellurite: unveiling an ancient enigma. | biochemical, genetic, enzymatic and molecular approaches were used to demonstrate, for the first time, that tellurite (teo(3) (2-)) toxicity in e. coli involves superoxide formation. this radical is derived, at least in part, from enzymatic teo(3) (2-) reduction. this conclusion is supported by the following observations made in k(2)teo(3)-treated e. coli bw25113: i) induction of the ibpa gene encoding for the small heat shock protein ibpa, which has been associated with resistance to superoxide ... | 2007 | 17299591 |
| synthesis of highly hydroxylated aromatics by evolved biphenyl dioxygenase and subsequent dihydrodiol dehydrogenase. | the evolved bpha1 (2049) gene, in which nine amino acids from the pseudomonas pseudoalcaligenes kf707 bpha1 were changed to those from the burkholderia xenovorans lb400 bpha1 (m247i, h255q, v258i, g268a, d303e, -313g, s324t, v325i, and t376n), was expressed in escherichia coli along with the bpha2a3a4 and bphb genes derived from strain kf707. this recombinant e. coli cells converted biphenyl and several heterocyclic aromatic compounds into the highly hydroxylated products such as biphenyl-2,3,2' ... | 2007 | 17401562 |
| enzymology and evolution of the pyruvate pathway to 2-oxobutyrate in methanocaldococcus jannaschii. | the archaeon methanocaldococcus jannaschii uses three different 2-oxoacid elongation pathways, which extend the chain length of precursors in leucine, isoleucine, and coenzyme b biosyntheses. in each of these pathways an aconitase-type hydrolyase catalyzes an hydroxyacid isomerization reaction. the genome sequence of m. jannaschii encodes two homologs of each large and small subunit that forms the hydrolyase, but the genes are not cotranscribed. the genes are more similar to each other than to p ... | 2007 | 17449626 |
| selection for biocontrol bacteria antagonistic toward rosellinia necatrix by enrichment of competitive avocado root tip colonizers. | biological control of soil-borne pathogens is frequently based on the application of antagonistic microorganisms selected solely for their ability to produce in vitro antifungal factors. the aim of this work was to select bacteria that efficiently colonize the roots of avocado plants and display antagonism towards rosellinia necatrix, the causal agent of avocado white root rot. a high frequency of antagonistic strains (ten isolates, 24.4%) was obtained using a novel procedure based on the select ... | 2007 | 17467245 |
| the cyanotrophic bacterium pseudomonas pseudoalcaligenes cect5344 responds to cyanide by defence mechanisms against iron deprivation, oxidative damage and nitrogen stress. | two-dimensional (2-d) electrophoresis approach has been used to test protein expression changes in response to cyanide in the alkaliphilic bacterium pseudomonas pseudoalcaligenes cect5344. this is a cyanide-assimilating strain which also grows in media containing cyanide-enriched effluent from the jewellery industry. the bacterium efficiently uses this residue as the sole nitrogen source for aerobic growth under alkaline ph with negligible nitrogen losses as hcn. cell-free extracts isolated from ... | 2007 | 17504491 |
| evaluation of the colorimetric vitek 2 card for identification of gram-negative nonfermentative rods: comparison to 16s rrna gene sequencing. | ninety strains of a collection of well-identified clinical isolates of gram-negative nonfermentative rods collected over a period of 5 years were evaluated using the new colorimetric vitek 2 card. the vitek 2 colorimetric system identified 53 (59%) of the isolates to the species level and 9 (10%) to the genus level; 28 (31%) isolates were misidentified. an algorithm combining the colorimetric vitek 2 card and 16s rrna gene sequencing for adequate identification of gram-negative nonfermentative r ... | 2007 | 17507509 |
| essential role of cytochrome bd-related oxidase in cyanide resistance of pseudomonas pseudoalcaligenes cect5344. | pseudomonas pseudoalcaligenes cect5344 grows in minimal medium containing cyanide as the sole nitrogen source. under these conditions, an o2-dependent respiration highly resistant to cyanide was detected in cell extracts. the structural genes for the cyanide-resistant terminal oxidase, cioa and ciob, are clustered and encode the integral membrane proteins that correspond to subunits i and ii of classical cytochrome bd, although the presence of heme d in the membrane could not be detected by diff ... | 2007 | 17574992 |
| molecular characterization of a novel ortho-nitrophenol catabolic gene cluster in alcaligenes sp. strain nyz215. | alcaligenes sp. strain nyz215 was isolated for its ability to grow on ortho-nitrophenol (onp) as the sole source of carbon, nitrogen, and energy and was shown to degrade onp via a catechol ortho-cleavage pathway. a 10,152-bp dna fragment extending from a conserved region of the catechol 1,2-dioxygenase gene was obtained by genome walking. of seven complete open reading frames deduced from this fragment, three (onpabc) have been shown to encode the enzymes involved in the initial reactions of onp ... | 2007 | 17616586 |
| carbapenemases: the versatile beta-lactamases. | carbapenemases are beta-lactamases with versatile hydrolytic capacities. they have the ability to hydrolyze penicillins, cephalosporins, monobactams, and carbapenems. bacteria producing these beta-lactamases may cause serious infections in which the carbapenemase activity renders many beta-lactams ineffective. carbapenemases are members of the molecular class a, b, and d beta-lactamases. class a and d enzymes have a serine-based hydrolytic mechanism, while class b enzymes are metallo-beta-lactam ... | 2007 | 17630334 |
| screening of delta-aminolevulinic acid dehydratase from pseudomonas strains as biosensor for lead and some other metals contamination. | delta-aminolevulinic acid dehydratase (alad; e.c. 4.2.1.24) is a metalloprotein and plays a crucial role in heme synthesis. its sensitivity to toxic metals depends on the metallic co-factors. in this study the effects of some heavy metals on alads activity of five pseudomonas isolates from akarçay stream (afyonkarahisar) have been studied in order to determine whether their alads could be used as biosensor for lead and other heavy metals contamination. the data obtained from the study were analy ... | 2007 | 17975741 |
| description of a novel indole-oxidizing bacterium pseudomonas indoloxydans sp. nov., isolated from a pesticide-contaminated site. | a gram-negative, deep brown-pigmented gammaproteobacteria, strain ipl-1(t), capable of oxidizing indole was isolated from a lindane-contaminated site and subjected to a polyphasic taxonomic study. most of the physiological and biochemical properties, major fatty acids (c(18:1)omega7c, c(16:1)omega7c/iso c(15:0) 2oh and c(16:0)), estimated dna g+c content (67.2mol%) and 16s rrna gene sequence analysis showed that strain ipl-1(t) belonged to the genus pseudomonas. strain ipl-1(t) exhibited highest ... | 2008 | 18406094 |
| biphenyl dioxygenase from an arctic isolate is not cold adapted. | biphenyl dioxygenase from the psychrotolerant bacterium pseudomonas sp. strain cam-1 (bpdo(cam-1)) was purified and found to have an apparent k(cat) for biphenyl of 1.1 +/- 0.1 s(-1) (mean +/- standard deviation) at 4 degrees c. in contrast, bpdo(lb400) from the mesophile burkholderia xenovorans lb400 had no detectable activity at this temperature. at 57 degrees c, the half-life of the bpdo(cam-1) oxygenase was less than half that of the bpdo(lb400) oxygenase. nevertheless, bpdo(cam-1) appears t ... | 2008 | 18424535 |
| pseudomonas pseudoalcaligenes kf707 upon biofilm formation on a polystyrene surface acquire a strong antibiotic resistance with minor changes in their tolerance to metal cations and metalloid oxyanions. | the susceptibility to various biocides was examined in planktonic cells and biofilms of the obligate aerobe, pcbs degrader, pseudomonas pseudoalcaligenes kf707. the toxicity of two antibiotics, amikacin and rifampicin, three metalloid oxyanions (aso2(-), seo3(2-), teo3(2-)) and three metal cations (cd2+, ni2+, al3+) was tested at two stages of the biofilm-development (4 and 24 h) and compared to planktonic cells susceptibility. mature biofilms formed in rich (lb, luria-bertani) medium were thick ... | 2008 | 18437359 |
| hydroquinone dioxygenase from pseudomonas fluorescens acb: a novel member of the family of nonheme-iron(ii)-dependent dioxygenases. | hydroquinone 1,2-dioxygenase (hqdo), an enzyme involved in the catabolism of 4-hydroxyacetophenone in pseudomonas fluorescens acb, was purified to apparent homogeneity. ligandation with 4-hydroxybenzoate prevented the enzyme from irreversible inactivation. hqdo was activated by iron(ii) ions and catalyzed the ring fission of a wide range of hydroquinones to the corresponding 4-hydroxymuconic semialdehydes. hqdo was inactivated by 2,2'-dipyridyl, o-phenanthroline, and hydrogen peroxide and inhibi ... | 2008 | 18502867 |
| antibacterial and preliminary phytochemical and physico-chemical analysis of eucalyptus citriodora hk leaf. | the present communication deals with some studies on the antibacterial, physico-chemical and phytochemical parameters of different extracts of eucalyptus citriodora leaf. the antibacterial study was performed using the agar ditch method on some clinically important bacteria, namely pseudomonas pseudoalcaligenes, proteus vulgaris, citrobacter freundii, staphylococcus subflava, bacillus megaterium, and enterobacter aerogenes. physico-chemical parameters namely water, methanol, 1,4-dioxane, dmf, ac ... | 2008 | 18569717 |
| degradation of fluorobiphenyl by pseudomonas pseudoalcaligenes kf707. | the biphenyl-degrading bacterium pseudomonas pseudoalcaligenes kf707 can use 2- and 4-fluorobiphenyl as sole carbon and energy sources. accumulation of fluorinated catabolites was determined by fluorine-19 nuclear magnetic spectroscopy (19f nmr) and revealed that growth on 4-fluorobiphenyl yielded 4-fluorobenzoate and 4-fluoro-1,2-dihydro-1,2-dihydroxybenzoate as major fluorometabolites; 2-fluorobenzoate and 2-fluoromuconic acid were observed in 2-fluorobiphenyl-grown cultures. pseudomonas pseud ... | 2008 | 18616594 |
| identifying competing aerobic nitrobenzene biodegradation pathways by compound-specific isotope analysis. | nitroaromatic compounds that contaminate soil and groundwater can be biodegraded by different, sometimes competing reaction pathways. we evaluated the combined use of compound-specific stable c and n isotope analysis to distinguish between enzymatic nitrobenzene oxidation by comamonas sp. strain js765 and partial reduction by pseudomonas pseudoalcaligenes strain js45 under aerobic conditions. bulk 13c and 15n enrichment factors for nitrobenzene dioxygenation with js765 were -3.9 per thousand +/- ... | 2008 | 18678003 |
| two similar enhanced root-colonizing pseudomonas strains differ largely in their colonization strategies of avocado roots and rosellinia necatrix hyphae. | pseudomonas alcaligenes avo73 and pseudomonas pseudoalcaligenes avo110 were selected previously as efficient avocado root tip colonizers, displaying in vitro antagonism towards rosellinia necatrix, causal agent of avocado white root rot. despite the higher number of antagonistic properties shown in vitro by avo73, only avo110 demonstrated significant protection against avocado white root rot. as both strains are enhanced root colonizers, and as colonization is crucial for the most likely biocont ... | 2008 | 18684119 |
| diversity of the c-terminal portion of the biphenyl dioxygenase large subunit. | the biphenyl dioxygenase (bpdo) catalyses a stereospecific dioxygenation of biphenyl and analogs of it. aside from being involved in the destruction and detoxification of toxic pollutants in soil, in the context of the green chemistry concept, this enzyme is a promising biocatalyst to design new more selective and more environmentally friendly approaches to manufacture fine chemicals. at this time, most of our knowledge about the variability of key residues determining the substrate specificity ... | 2008 | 18685267 |
| characterization of the pseudomonas pseudoalcaligenes cect5344 cyanase, an enzyme that is not essential for cyanide assimilation. | cyanase catalyzes the decomposition of cyanate into co(2) and ammonium, with carbamate as an unstable intermediate. the cyanase of pseudomonas pseudoalcaligenes cect5344 was negatively regulated by ammonium and positively regulated by cyanate, cyanide, and some cyanometallic complexes. cyanase activity was not detected in cell extracts from cells grown with ammonium, even in the presence of cyanate. nevertheless, a low level of cyanase activity was detected in nitrogen-starved cells. the cyn gen ... | 2008 | 18708510 |
| protein engineering on biphenyl dioxygenase for conferring activity to convert 7-hydroxyflavone and 5,7-dihydroxyflavone (chrysin). | a central part (amino-acid position 268-397 of 458 amino-acid residues) of the biphenyl dioxygenase large (alpha) subunit, bpha1, from pseudomonas pseudoalcaligenes strain kf707 was exchanged with the corresponding part of bpha1 from another biphenyl-degrading bacterium, pseudomonas putida strain kf715, to construct hybrid bpha1, bpha1 (715-707). when expressed in escherichia coli together with the bpha2a3a4bc genes from strain kf707, this enzyme was shown to possess activity for degrading both ... | 2008 | 18804053 |
| the gaf-like-domain-containing transcriptional regulator dfdr is a sensor protein for dibenzofuran and several hydrophobic aromatic compounds. | dibenzofuran (df) is one of the dioxin carbon skeletal compounds used as a model to study the microbial degradation of dioxins. this study analyzed the transcriptional regulation of the df dioxygenase genes dfda1 to dfda4 in the df-utilizing actinomycetes rhodococcus sp. strain yk2 and terrabacter sp. strain yk3. an open reading frame designated dfdr was detected downstream of the dfdc genes. the c-terminal part of the dfdr amino acid sequence has high levels of similarity to several luxr-type d ... | 2009 | 18952799 |
| the gaf-like-domain-containing transcriptional regulator dfdr is a sensor protein for dibenzofuran and several hydrophobic aromatic compounds. | dibenzofuran (df) is one of the dioxin carbon skeletal compounds used as a model to study the microbial degradation of dioxins. this study analyzed the transcriptional regulation of the df dioxygenase genes dfda1 to dfda4 in the df-utilizing actinomycetes rhodococcus sp. strain yk2 and terrabacter sp. strain yk3. an open reading frame designated dfdr was detected downstream of the dfdc genes. the c-terminal part of the dfdr amino acid sequence has high levels of similarity to several luxr-type d ... | 2009 | 18952799 |
| microbial degradation of pyridine and alpha-picoline using a strain of the genera pseudomonas and nocardia sp. | biodegradation of pyridine and alpha-picoline (2-methyl pyridine) by pseudomonas pseudoalcaligenes-kpn and nocardia sp. isolated from garden soil were investigated in batch culture experiments. pyridine and alpha-picoline (50-200 mg l(-1)) were used as sole source of carbon and energy in the investigation. the kinetic constants were evaluated for pyridine and alpha-picoline degradation under optimized nutritional (c, n, p) and environmental (ph, temperature) conditions. the values of bio-kinetic ... | 2009 | 18987898 |
| metabolomic investigation of the bacterial response to a metal challenge. | pseudomonas pseudoalcaligenes kf707 is naturally resistant to the toxic metalloid tellurite, but the mechanisms of resistance are not known. in this study we report the isolation of a kf707 mutant (t5) with hyperresistance to tellurite. in order to characterize the bacterial response and the pathways leading to tolerance, we utilized phenotype microarray technology (biolog) and a metabolomic technique based on nuclear magnetic resonance spectroscopy. the physiological states of kf707 wild-type a ... | 2009 | 19047385 |
| biotransformations of 2-methylisoborneol by camphor-degrading bacteria. | many camphor-degrading bacteria that are able to transform 2-methylisoborneol (2-mib) have been identified. three of these strains have been examined in detail. rhodococcus ruber t1 metabolizes camphor through 6-hydroxycamphor but converts 2-mib to 3-hydroxy-2-mib. pseudomonas putida g1, which metabolizes camphor through 5-hydroxycamphor, converts mib primarily to 6-hydroxy-2-mib. rhodococcus wratislaviensis dlc-cam converts 2-mib through 5-hydroxy-2-mib to 5-keto-2-mib. together, these three st ... | 2009 | 19060161 |
| biotransformations of 2-methylisoborneol by camphor-degrading bacteria. | many camphor-degrading bacteria that are able to transform 2-methylisoborneol (2-mib) have been identified. three of these strains have been examined in detail. rhodococcus ruber t1 metabolizes camphor through 6-hydroxycamphor but converts 2-mib to 3-hydroxy-2-mib. pseudomonas putida g1, which metabolizes camphor through 5-hydroxycamphor, converts mib primarily to 6-hydroxy-2-mib. rhodococcus wratislaviensis dlc-cam converts 2-mib through 5-hydroxy-2-mib to 5-keto-2-mib. together, these three st ... | 2009 | 19060161 |
| [transformation of core pseudomonas pseudoalcaligene insecticidal protein gene and its insecticidal expression in tobacco]. | we studied the effect of the signal peptide sequence (sps) on the expression of pseudomonas pseudoalcaligenes insecticidal protein gene (ppip). | 2008 | 19062644 |
| pseudomonas tuomuerensis sp. nov., isolated from a bird's nest. | strain 78-123t was isolated from a sample of a bird's nest situated on the bank of qiongtailan river in the region of tuomuer peak of tianshan mountain in the xin-jiang uygur autonomous region in north-western china. phylogenetic analysis based on 16s rrna gene sequence similarity showed that strain 78-123t was related to members of the genus pseudomonas. 16s rrna gene sequence similarity between strain 78-123t and pseudomonas mendocina atcc 25411t, pseudomonas pseudoalcaligenes jcm 5968t and ps ... | 2009 | 19126738 |
| a new atisane-type diterpene from the bark of the mangrove plant excoecaria agallocha. | a new atisane-type diterpene, ent-16alpha-hydroxy-atisane-3,4-lactone (4) and three known diterpenes, ent-16alpha-hydroxy-atisane-3-one (1), ent-atisane-3beta,16alpha-diol (2), ent-3,4-seco-16alpha-hydroxyatis- 4(19)-en -3-oic acid (3) were isolated from the bark of the mangrove plant excoecaria agallocha. their structures and relative stereochemistry were elucidated by means of extensive nmr and ms analysis. compound 3 exhibited significant anti-microfouling activity against the adherence of ps ... | 2009 | 19158653 |
| effects of biocides and other metal removal fluid constituents on mycobacterium immunogenum. | cells of mycobacterium immunogenum are significantly more resistant to biocides and antimicrobial compounds used for disinfection of metal removal fluids (mrfs) than cells of the gram-negative bacterium pseudomonas pseudoalcaligenes. to ensure accurate measurement of m. immunogenum susceptibility, a biocide inactivation step must be included to prevent an overestimation of killing for short-term exposures. cell suspensions in 5% mrf for 30 min rather than direct plating following biocide exposur ... | 2009 | 19201985 |
| chemotaxis to pyrimidines and identification of a cytosine chemoreceptor in pseudomonas putida. | we developed a high-throughput quantitative capillary assay and demonstrated that pseudomonas putida strains f1 and prs2000 were attracted to cytosine, but not thymine or uracil. in contrast, pseudomonas aeruginosa pao1 was not chemotactic to any pyrimidines. chemotaxis assays with a mutant strain of f1 in which the putative methyl-accepting chemotaxis protein-encoding gene pput_0623 was deleted revealed that this gene (designated mcpc) encodes a chemoreceptor for positive chemotaxis to cytosine ... | 2009 | 19251854 |
| population development and reproduction of fungus- and bacterium feeding nematodes in the presence of insect growth regulators. | the insect growth regulators (igrs), diflubenzuron and bay sir 8514, at 300 and 1,000 ppm a.i. in potato dextrose agar (pda) inhibited the radial growth of the fungus rhizoctonia solani host of aphelenchus avenae. the igrs had no effect on the growth of the bacterium pseudomonas pseudoalcaligenes host of acrobeloides nanus and diplogaster iheritieri. at 59 ppm a.i., neither igr inhibited the population development of a. nanus and d. iheritieri on p. pseudoalcaligenes; however, diflubenzuron stim ... | 1983 | 19295773 |
| metalworking fluids biodiversity characterization. | hypersensitivity pneumonitis of machinists associated with metalworking fluids (mwf) was recently linked to mycobacterium immunogenum. in addition to mycobacterium, impacts of continuous and massive contact to other micro-organisms, such as pseudomonas, were little studied. this report intended to quantify and characterize the microbial load of 44 in-use mwf. | 2010 | 19614850 |
| pseudomonas caeni sp. nov., a denitrifying bacterium isolated from the sludge of an anaerobic ammonium-oxidizing bioreactor. | two gram-negative, rod-shaped, motile, aerobic bacterial strains designated hy-14(t) and hy-24 were isolated from the sludge of an anaerobic ammonium-oxidizing bioreactor. the strains could not grow with 5 % (w/v) nacl, did not produce acid from d-glucose or utilize d-glucose, gluconate or citrate as a sole carbon source. summed feature 3 and c(16 : 0) were the most abundant fatty acids; hydroxyl fatty acids c(12 : 0) 3-oh and c(10 : 0) 3-oh were also present. fatty acid c(12 : 0) 2-oh was absen ... | 2009 | 19622647 |
| dna-stable isotope probing integrated with metagenomics for retrieval of biphenyl dioxygenase genes from polychlorinated biphenyl-contaminated river sediment. | stable isotope probing with [(13)c]biphenyl was used to explore the genetic properties of indigenous bacteria able to grow on biphenyl in pcb-contaminated river raisin sediment. a bacterial 16s rrna gene clone library generated from [(13)c]dna after a 14-day incubation with [(13)c]biphenyl revealed the dominant organisms to be members of the genera achromobacter and pseudomonas. a library built from pcr amplification of genes for aromatic-ring-hydroxylating dioxygenases from the [(13)c]dna fract ... | 2009 | 19648381 |
| changes in growth parameters of pseudomonas pseudoalcaligenes after ten months culturing at increasing temperature. | abstract in this paper, we report the thermal adaptation of pseudomonas pseudoalcaligenes, characterized as changes in growth parameters. six clones derived from a single colony of p. pseudoalcaligenes were cultured in two different temperature regimes for 10 months, with three clones forming the control group, cultured at a constant temperature, and another three clones forming the high-temperature (ht) group, cultured at increasing temperature (from 41 to 47 degrees c). three growth parameters ... | 2003 | 19719623 |
| terminal-restriction fragment length polymorphism analysis of biphenyl dioxygenase genes from a polychlorinated biphenyl-polluted soil. | polychlorinated biphenyls (pcbs) are ubiquitous persistent organic pollutants that can be co-metabolically biotransformed by biphenyl-utilizing bacteria. in this study, terminal-restriction fragment length polymorphism (t-rflp) was applied to the substrate specificity-determining region of the 2,3-biphenyl dioxygenase encoding genes of a microbial community found in a pcb-polluted soil. notably, both the total biphenyl/pcb-utilizing community and its members actively expressing the 2,3-biphenyl ... | 2009 | 19835952 |
| time-dependent density functional theory-assisted absolute configuration determination of cis-dihydrodiol metabolite produced from isoflavone by biphenyl dioxygenase. | escherichia coli cells containing the biphenyl dioxygenase genes bpha1a2a3a4 from pseudomonas pseudoalcaligenes kf707 were found to biotransform isoflavone and produced a metabolite that was not found in a control experiment. liquid chromatography/mass spectrometry (lc/ms) and (1)h and (13)c nuclear magnetic resonance (nmr) analyses indicated that biphenyl dioxygenase induced 2',3'-cis-dihydroxylation of the b-ring of isoflavone. in a previous report, the same enzyme showed dioxygenase activity ... | 2010 | 19854147 |
| integrated bioprocessing for the ph-dependent production of 4-valerolactone from levulinate in pseudomonas putida kt2440. | enzymes are powerful biocatalysts capable of performing specific chemical transformations under mild conditions, yet as catalysts they remain subject to the laws of thermodynamics, namely, that they cannot catalyze chemical reactions beyond equilibrium. here we report the phenomenon and application of using extracytosolic enzymes and medium conditions, such as ph, to catalyze metabolic pathways beyond their intracellular catalytic limitations. this methodology, termed "integrated bioprocessing" ... | 2010 | 19915035 |
| integrated bioprocessing for the ph-dependent production of 4-valerolactone from levulinate in pseudomonas putida kt2440. | enzymes are powerful biocatalysts capable of performing specific chemical transformations under mild conditions, yet as catalysts they remain subject to the laws of thermodynamics, namely, that they cannot catalyze chemical reactions beyond equilibrium. here we report the phenomenon and application of using extracytosolic enzymes and medium conditions, such as ph, to catalyze metabolic pathways beyond their intracellular catalytic limitations. this methodology, termed "integrated bioprocessing" ... | 2010 | 19915035 |
| characterization of the isophthalate degradation genes of comamonas sp. strain e6. | the isophthalate (ipa) degradation gene cluster (iphacbdr) responsible for the conversion of ipa into protocatechuate (pca) was isolated from comamonas sp. strain e6, which utilizes phthalate isomers as sole carbon and energy sources via the pca 4,5-cleavage pathway. based on amino acid sequence similarity, the ipha, iphc, iphb, iphd, and iphr genes were predicted to code for an oxygenase component of ipa dioxygenase (ipado), a periplasmic ipa binding receptor, a 1,2-dihydroxy-3,5-cyclohexadiene ... | 2010 | 19933340 |
| characterization of the isophthalate degradation genes of comamonas sp. strain e6. | the isophthalate (ipa) degradation gene cluster (iphacbdr) responsible for the conversion of ipa into protocatechuate (pca) was isolated from comamonas sp. strain e6, which utilizes phthalate isomers as sole carbon and energy sources via the pca 4,5-cleavage pathway. based on amino acid sequence similarity, the ipha, iphc, iphb, iphd, and iphr genes were predicted to code for an oxygenase component of ipa dioxygenase (ipado), a periplasmic ipa binding receptor, a 1,2-dihydroxy-3,5-cyclohexadiene ... | 2010 | 19933340 |
| pseudomonas oleovorans subsp. lubricantis subsp. nov., and reclassification of pseudomonas pseudoalcaligenes atcc 17440t as later synonym of pseudomonas oleovorans atcc 8062 t. | isolate rs1(t) isolated from used metalworking fluid was found to be a gram-negative, motile, and non-spore forming rod. based on phylogenetic analyses with 16s rrna, isolate rs1(t) was placed into the mendocina sublineage of pseudomonas. the major whole cell fatty acids were c(18:1)omega7c (32.6%), c(16:0) (25.5%), and c(15:0) iso 2oh/c(16:1)omega7c (14.4%). the sequence similarities of isolate rs1(t) based on gyrb and rpod genes were 98.9 and 98.0% with pseudomonas pseudoalcaligenes, and 98.5 ... | 2010 | 19936829 |
| modified 3-oxoadipate pathway for the biodegradation of methylaromatics in pseudomonas reinekei mt1. | catechols are central intermediates in the metabolism of aromatic compounds. degradation of 4-methylcatechol via intradiol cleavage usually leads to the formation of 4-methylmuconolactone (4-ml) as a dead-end metabolite. only a few microorganisms are known to mineralize 4-ml. the mml gene cluster of pseudomonas reinekei mt1, which encodes enzymes involved in the metabolism of 4-ml, is shown here to encode 10 genes found in a 9.4-kb chromosomal region. reverse transcription assays revealed that t ... | 2010 | 20061479 |
| metalworking fluid-related aerosols in machining plants. | respiratory problems are observed in machinists using soluble metalworking fluid (mwf). evidences suggest that these problems could be related to the aerosolized microorganisms and their byproducts from mwf. to establish mwf aerosol exposure thresholds and to better understand their effect on human health, these aerosols must be fully characterized. this article evaluates airborne microorganisms and aerosols from soluble mwf in the working environment. air quality parameters (endotoxin levels, c ... | 2010 | 20229391 |
| alkaline cyanide degradation by pseudomonas pseudoalcaligenes cect5344 in a batch reactor. influence of ph. | water containing cyanide was biologically detoxified with the bacterial strain pseudomonas pseudoalcaligenes cect5344 in a batch reactor. volatilization of toxic hydrogen cyanide (hcn) was avoided by using an alkaline medium for the treatment. the operational procedure was optimized to assess cyanide biodegradation at variable ph values and dissolved oxygen concentrations. using an initial ph of 10 without subsequent adjustment allowed total cyanide to be consumed at a mean rate of approximately ... | 2010 | 20346583 |
| experimental evidence that source genetic variation drives pathogen emergence. | a pathogen can readily mutate to infect new host types, but this does not guarantee successful establishment in the new habitat. what factors, then, dictate emergence success? one possibility is that the pathogen population cannot sustain itself on the new host type (i.e. host is a sink), but migration from a source population allows adaptive sustainability and eventual emergence by delivering beneficial mutations sampled from the source's standing genetic variation. this idea is relevant regard ... | 2010 | 20484240 |
| nitroaromatic compounds, from synthesis to biodegradation. | nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. this important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. unfortunately, their extensive use has led to environmental contamination of soil and groundwater. the nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalc ... | 2010 | 20508249 |
| an intramolecular disulfide bond is required for the thermostability of methyl parathion hydrolase, ophc2. | ophc2, a methyl parathion hydrolase (mph) from pseudomonas pseudoalcaligenes c2-1 (cgmcc 1150), can degrade a wide range of organophosphate pesticides. compared with other mphs, ophc2 exhibits high thermostability. its thermostability mechanism, however, remains unknown. in the present study, sequence analysis demonstrated that two cysteines (cys110 and cys146) exist in ophc2, but not in other mphs. the three-dimensional structural model of ophc2 performed by computer-assisted homology modelling ... | 2010 | 20607231 |
| structural characterization of iscr8, iscr22, and iscr23, subgroups of is91-like insertion elements. | analysis of iscr8 (ispps1) revealed that this group of insertion elements has to be subdivided into three subgroups: iscr8, iscr22, and iscr23. the distinction of three subgroups is supported by phylogenetic analysis of the transposase open reading frames (orfs). comparison of over 20 complete and partial iscr8/22/23 elements identified oriis candidate sequences for all groups and a teris candidate sequence for iscr8. the oriis sequences, their distance to the transposase orfs, and the sequence ... | 2010 | 20625149 |
| efficiency of phenol biodegradation by planktonic pseudomonas pseudoalcaligenes (a constructed wetland isolate) vs. root and gravel biofilm. | in the last two decades, constructed wetland systems gained increasing interest in wastewater treatment and as such have been intensively studied around the world. while most of the studies showed excellent removal of various pollutants, the exact contribution, in kinetic terms, of its particular components (such as: root, gravel and water) combined with bacteria is almost nonexistent. in the present study, a phenol degrader bacterium identified as pseudomonas pseudoalcaligenes was isolated from ... | 2010 | 20705318 |
| hybrid pseudomonads engineered by two-step homologous recombination acquire novel degradation abilities toward aromatics and polychlorinated biphenyls. | pseudomonas pseudoalcaligenes kf707 possesses a chromosomally encoded bph gene cluster responsible for the catabolism of biphenyl and polychlorinated biphenyls. previously, we constructed chimeric versions of the bpha1 gene, which encodes a large subunit of biphenyl dioxygenase, by using dna shuffling between bpha1 genes from p. pseudoalcaligenes kf707 and burkholderia xenovorans lb400. in this study, we demonstrate replacement of the bpha1 gene with chimeric bpha1 sequence within the chromosoma ... | 2010 | 20809076 |
| biodegradation of polyfluorinated biphenyl in bacteria. | fluorinated aromatic compounds are significant environmental pollutants, and microorganisms play important roles in their biodegradation. the effect of fluorine substitution on the transformation of fluorobiphenyl in two bacteria was investigated. pseudomonas pseudoalcaligenes kf707 and burkholderia xenovorans lb400 used 2,3,4,5,6-pentafluorobiphenyl and 4,4'-difluorobiphenyl as sole sources of carbon and energy. the catabolism of the fluorinated compounds was examined by gas chromatography-mass ... | 2010 | 20830605 |
| tolerance of pseudomonas pseudoalcaligenes kf707 to metals, polychlorobiphenyls and chlorobenzoates: effects on chemotaxis-, biofilm- and planktonic-grown cells. | pseudomonas pseudoalcaligenes kf707 is a polychlorinated biphenyls (pcbs) degrader, also tolerant to several toxic metals and metalloids. the work presented here examines for the first time the chemotactic response of p. pseudoalcaligenes kf707 to biphenyl and intermediates of the pcb biodegradation pathway in the presence and absence of metals. chemotaxis analyses showed that biphenyl, benzoic acid and chlorobenzoic acids acted as chemoattractants for kf707 cells and that metal cations such as ... | 2010 | 20846140 |
| application of a novel bacterial consortium for mineralization of sulphonated aromatic amines. | a novel bacterial consortium (tj-2) for mineralization of aromatic amines resulting from decolorization of azo dyes was developed. three bacterial strains were identified as pseudomonas pseudoalcaligenes (tj-21,eu072476), pseudomonas citronellolis (tj-22,eu072477) and pseudomonas testosterone (tj-23,eu072477) by 16s rrna gene sequence analysis. aromatic amine mineralization under aerobic conditions was observed to be significantly higher with the consortium as compared to pure strains indicating ... | 2010 | 20863689 |
| absolute configuration-dependent epoxide formation from isoflavan-4-ol stereoisomers by biphenyl dioxygenase of pseudomonas pseudoalcaligenes strain kf707. | biphenyl dioxygenase from pseudomonas pseudoalcaligenes strain kf707 expressed in escherichia coli was found to exhibit monooxygenase activity toward four stereoisomers of isoflavan-4-ol. lc-ms and lc-nmr analyses of the metabolites revealed that the corresponding epoxides formed between c2' and c3' on the b-ring of each isoflavan-4-ol substrate were the sole products. the relative reactivity of the stereoisomers was found to be in the order: (3s,4s)-cis-isoflavan-4-ol > (3r,4s)-trans-isoflavan- ... | 2010 | 21063701 |