Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| xylene monooxygenase, a membrane-spanning non-heme diiron enzyme that hydroxylates hydrocarbons via a substrate radical intermediate. | the non-heme diiron enzyme xylene monooxygenase (xylm) has been shown to hydroxylate hydrocarbons via a hydrogen abstraction-carbon radical recombination mechanism (oxygen rebound). using the radical clock bicyclo[4.1.0]heptane (norcarane) in a whole-cell assay, and observing the ratio of rearranged 3-(hydroxymethyl)cyclohexene and unrearranged 2-norcaranol products, the lifetime of the substrate radical was determined to be approximately 0.2 ns. the wild-type organism pseudomonas putida mt-2 an ... | 2003 | 12811621 |
| microbial contamination of dialysate and its prevention in haemodialysis units. | at the haemodialysis centres of nine hospitals in japan, microbial contamination of treated water (reverse osmosis method), acid and bicarbonate concentrates, and dialysate was investigated. among these fluids used in haemodialysis, the dialysate was most frequently contaminated and had the highest concentration of bacteria. of 40 dialysate samples analysed, 42.5% showed a bacterial count of more than 2000cfu/ml, which was above the association for the advancement of medical instrumentation (aam ... | 2003 | 12818584 |
| a novel antarctic microbial endolithic community within gypsum crusts. | a novel endolithic microbial habitat is described from a climatically extreme site at two step cliffs, alexander island, antarctic peninsula (71 degrees 54's, 68 degrees 13'w). small endolithic colonies (<3 mm in diameter) are found within the translucent gypsum crust that forms on the surface of sandstone boulders. gypsum crusts are found on ice-free rocks throughout the antarctic and therefore offer potential colonization sites at more inhospitable locations, including sites at higher latitude ... | 2003 | 12823188 |
| rhizoremediation of dioxin-like compounds by a recombinant rhizobium tropici strain expressing carbazole 1,9a-dioxygenase constitutively. | a recombinant rhizobium strain, pbk3-is, that constitutively expressed the oxygenase component of carbazole 1,9a-dioxygenase from sphingomonas sp. strain ka1, was constructed. in the water-cultured siratro rhizospheres inoculated with strain pbk3-is, 48% of the dibenzofuran was removed within 3 days (initial substrate, 25 microg). similar results were obtained in soil-cultured siratro rhizospheres using sterile vermiculite. when non-sterile field soils were used instead of sterile vermiculite, t ... | 2003 | 12834297 |
| a common structure of substrate shared by lignostilbenedioxygenase isozymes from sphingomonas paucimobilis tmy1009. | a common structure of substrates of lignostilbenedioxygenases was investigated using synthesized stilbenes. cell-free extracts of sphingomonas paucimobilis tmy1009 degraded only trans-4-hydroxystilbene and trans-4-hydroxy-3-methoxystilbene. other stilbenes that had no 4-hydroxyl group and had a cis structure were not substrates for lignostilbenedioxygenases. these results indicate that a 4-hydroxyl group and trans-structure is necessary for the common structure for substrates of lignostilbenedio ... | 2003 | 12843670 |
| biodegradation of nonylphenol in a continuous packed-bed bioreactor. | a packed bed bioreactor, with 170 ml glass bead carriers and 130 ml medium, was tested for the removal of the endocrine disrupter, nonylphenol, with a sphingomonas sp. the bioreactor was first continuously fed with medium saturated with nonylphenol in an attempt to simulate groundwater pollution. at best, nonylphenol was degraded by 99.5% at a feeding rate of 69 ml h(-1) and a removal rate of 4.3 mg nonylphenol day(-1), resulting in a 7.5-fold decrease in effluent toxicity according to the micro ... | 2003 | 12889825 |
| simultaneous and rapid monitoring of biomass and biopolymer production by sphingomonas paucimobilis using fourier transform-near infrared spectroscopy. | the application of fourier transform near infrared spectroscopy (ft-nirs) to near real-time monitoring of polysaccharide and biomass concentration was investigated using a gellan-producing strain of sphingomonas paucimobilis grown in a stirred tank reactor. successful models for both biomass and gellan were constructed despite the physichochemical complexity of the viscous process fluid. modelling of biomass proved more challenging than for gellan, partly because of the low range of biomass conc ... | 2003 | 12889834 |
| implication of two glutathione s-transferases in the optimal metabolism of m-toluate by sphingomonas yanoikuyae b1. | a putative glutathione s-transferase (gst) gene (bphk) was identified in the meta-cleavage operon for the degradation of m-toluate by sphingomonas yanoikuyae b1. disruption of bphk resulted in the loss of gst activity against 1-chloro-2,4-dinitrobenzene and a much increased lag time of the mutant strain mb3 (bphk::km) following subculture into m-toluate medium. in contrast, an increased lag time was not observed when mb3 was grown on biphenyl or m-xylene and mb3 showed normal growth on m-toluate ... | 2003 | 12906359 |
| biodegradation of methyl tertiary butyl ether (mtbe) by a bacterial enrichment consortia and its monoculture isolates. | methyl tertiary butyl ether (mtbe), an important gasoline additive, is a recalcitrant compound posing serious environmental health problems. in this study, mtbe-degrading bacteria were enriched from five environmental samples. enrichments from stewart lake sediments and an mtbe contaminated soil displayed the highest rate of mtbe removal; 29.6 and 27.8% respectively, in 28 days. a total of 12 bacterial monocultures isolated from enrichment cultures were screened for mtbe degradation in liquid cu ... | 2003 | 12906382 |
| screening of bifidobacterium strains isolated from human faeces for antagonistic activities against potentially bacterial pathogens. | as probiotic bacteria, strains belonging to the genus bifidobacterium colonise the gastro-intestinal tract of humans and animals at the time of birth, and they are found in young as well as in adult individuals in great numbers. moreover, they can interact with the development of enteric infections by the production of antimicrobial metabolites. in this work 281 strains of bifidobacteria were anaerobically isolated from human faecal samples, supplied by volunteers of different ages (youngs, adul ... | 2003 | 12906392 |
| potential of a new biotreatment: sphingomonas cloacae s-3t degrades nonylphenol in industrial wastewater. | sphingomonas cloacae s-3(t), a nonylphenol (np)-degrading bacterium, was evaluated for its utility in the remediation of np-contaminated wastewater. in flask-scale experiments, s-3(t) cells immobilized on porous polypropylene carriers (beads) efficiently degraded np to concentrations routinely measured in aquatic environments [a few parts per billion (ppb), or micrograms per liter). therefore, we constructed and evaluated a laboratory-scale wastewater treatment system with a 3-l carrier-filled c ... | 2003 | 12915961 |
| mineralization of soil-aged isoproturon and isoproturon metabolites by sphingomonas sp. strain srs2. | the aim of the study was to determine the effect of aging of the herbicide isoproturon and its metabolites monodesmethyl-isoproturon and 4-isopropyl-aniline in agricultural soil on their availability to the degrading bacterium sphingomonas sp. strain srs2. the 14c-ring-labeled isoproturon, monodesmethyl-isoproturon, and 4-isopropyl-aniline were added to sterilized soil and stored for 1, 49, 71, or 131 d before inoculation with strain srs2. the availability of the compounds was estimated from the ... | 2003 | 12931879 |
| haloalkane dehalogenase linb from sphingomonas paucimobilis ut26: x-ray crystallographic studies of dehalogenation of brominated substrates. | the haloalkane dehalogenases are detoxifying enzymes that convert a broad range of halogenated substrates to the corresponding alcohols. complete crystal structures of haloalkane dehalogenase from sphingomonas paucimobilis ut26 (linb), and complexes of linb with 1,2-propanediol/1-bromopropane-2-ol and 2-bromo-2-propene-1-ol, products of debromination of 1,2-dibromopropane and 2,3-dibromopropene, respectively, were determined from 1.8 a resolution x-ray diffraction data. published structures of n ... | 2003 | 12939138 |
| ice from an ice machine is a potential source of bacterial contamination for hpc products -- implications for cell-processing facilities. | 2003 | 12944241 | |
| biodegradation of selected uv-irradiated and non-irradiated polycyclic aromatic hydrocarbons (pahs). | biodegradation of uv-irradiated anthracene, pyrene, benz[a]anthracene, and dibenz[a,h]anthracene was compared to that of the non-irradiated samples, individually and in synthetic mixtures with enrichment cultures. combined treatment was repeated for individual anthracene and for the pah mixture with sphingomonas sp. strain epa 505 and sphingomonas yanoikuyae. enrichment culture studies were performed on the pah mixtures in the presence of the main photoproduct of anthracene, pure 9,10-anthracene ... | 2003 | 12948055 |
| catalytic mechanism of the maloalkane dehalogenase linb from sphingomonas paucimobilis ut26. | haloalkane dehalogenases are bacterial enzymes capable of carbon-halogen bond cleavage in halogenated compounds. to obtain insights into the mechanism of the haloalkane dehalogenase from sphingomonas paucimobilis ut26 (linb), we studied the steady-state and presteady-state kinetics of the conversion of the substrates 1-chlorohexane, chlorocyclohexane, and bromocyclohexane. the results lead to a proposal of a minimal kinetic mechanism consisting of three main steps: (i) substrate binding, (ii) cl ... | 2003 | 12952988 |
| preferential surfactant utilization by a pah-degrading strain: effects on micellar solubilization phenomena. | biodegradable nonionic tween series surfactants were employed to assess the effects of synthetic surfactants on the bioavailability of a target polycyclic aromatic hydrocarbon (pah), phenanthrene, in soil/sediment-free micellar solutions. dosages of surfactants in excess of their respective critical micelle concentrations (cmcs) dramatically enhanced solubilization of phenanthrene, but the micellar-solubilized phenanthrene was neither directly nor readily bioavailable to the pah-degrading strain ... | 2003 | 12953868 |
| biochemical and molecular characterization of poly(aspartic acid) hydrolase-2 from sphingomonas sp. kt-1. | poly(aspartic acid) (paa) hydrolase-2 was purified from crude soluble cellular extracts of sphingomonas sp. kt-1 (jcm10459) and characterized to elucidate the mechanism of alpha,beta-poly(d,l-aspartic acid) (tpaa) biodegradation. the molecular mass of paa hydrolase-2 was 42 kda, and the isoelectric point was 9.6. the optimum values of ph and temperature for the hydrolysis of alpha-di(l-aspartic acid) by paa hydrolase-2 were 7.0 and 55 degrees c, respectively. the effect of inhibitors on the hydr ... | 2003 | 12959596 |
| characterization and regulation of the genes for a novel anthranilate 1,2-dioxygenase from burkholderia cepacia dbo1. | anthranilate (2-aminobenzoate) is an important intermediate in tryptophan metabolism. in order to investigate the degradation of tryptophan through anthranilate by burkholderia cepacia, several plasposon mutations were constructed of strain dbo1 and one mutant with the plasposon insertion in the anthranilate dioxygenase (antdo) genes was chosen for further study. the gene sequence obtained from flanking dna of the plasposon insertion site revealed unexpected information. b. cepacia dbo1 antdo (d ... | 2003 | 13129960 |
| sphingomonas aurantiaca sp. nov., sphingomonas aerolata sp. nov. and sphingomonas faeni sp. nov., air- and dustborne and antarctic, orange-pigmented, psychrotolerant bacteria, and emended description of the genus sphingomonas. | seven psychrotolerant, gram-negative bacterial strains, five dust- and airborne isolates (ma101b(t), ma306a, ma405/90, ma-olki(t) and nw12(t)) and two from the antarctic (ant 20 and m3c203b-b), were subjected to a polyphasic characterization to determine their taxonomic position. high 16s rdna sequences similarities (99.3-100.0 %) demonstrated that they were closely related to each other. phylogenetic evaluation of their 16s rdna sequences revealed that they are members of the genus sphingomonas ... | 2003 | 13130003 |
| argimicins b and c, new anti-cyanobacterial compounds produced by sphingomonas sp. m-17. | 2003 | 14513910 | |
| microbial degradation of high and low molecular weight polyaromatic hydrocarbons in a two-phase partitioning bioreactor by two strains of sphingomonas sp. | a mixture of six polyaromatic hydrocarbons (naphthalene, phenanthrene, fluoranthene, pyrene, chyrysene and benzo[a]pyrene), varying in size from 2 to 5 rings, was dissolved in dodecane, and used as the delivery phase of a partitioning bioreactor. two species of sphingomonas were then used individually, and as a consortium, to determine which of the pahs were degraded. only low molecular weight pahs (naphthalene, phenanthrene and fluoranthene) were degraded by the individual strains, but the cons ... | 2003 | 14514047 |
| modification of activity and specificity of haloalkane dehalogenase from sphingomonas paucimobilis ut26 by engineering of its entrance tunnel. | structural comparison of three different haloalkane dehalogenases suggested that substrate specificity of these bacterial enzymes could be significantly influenced by the size and shape of their entrance tunnels. the surface residue leucine 177 positioned at the tunnel opening of the haloalkane dehalogenase from sphingomonas paucimobilis ut26 was selected for modification based on structural and phylogenetic analysis; the residue partially blocks the entrance tunnel, and it is the most variable ... | 2003 | 14525993 |
| enantioselective trans dihydroxylation of nonactivated c-c double bonds of aliphatic heterocycles with sphingomonas sp. hxn-200. | the bacterial strain sphingomonas sp. hxn-200 was used to catalyze the trans dihydroxylation ofn-substituted 1,2,5,6-tetrahydropyridines 1 and 3-pyrrolines 4 giving the corresponding 3,4-dihydroxypiperidines 3 and 3,4-dihydroxypyrrolidines 6, respectively, with high enantioselectivity and high activity. the trans dihydroxylation was sequentially catalyzed by a monooxygenase and an epoxide hydrolase in the strain with epoxide as intermediate. while both epoxidation and hydrolysis steps contribute ... | 2003 | 14575492 |
| bacterial growth and biofilm production on pyrene. | enrichment cultures inoculated with arctic soil yielded a biofilm that grew on pyrene and phenanthrene. in a 60-day period, the biofilm degraded 20 microg ml(-1) pyrene or 39 microg ml(-1) phenanthrene. single colonized pyrene crystals (approximately 1.5x0.75x0.35 mm) yielded 10(11) culturable heterotrophs and 10(5) biofilm propagules. analysis of ribosomal intergenic spacers identified six phylotypes in a clone library from the pyrene biofilm. analysis of 16s rrna gene sequences indicated that ... | 2002 | 19709207 |
| cloning and characterization of lin genes responsible for the degradation of hexachlorocyclohexane isomers by sphingomonas paucimobilis strain b90. | hexachlorocyclohexane (hch) has been used extensively against agricultural pests and in public health programs for the control of mosquitoes. commercial formulations of hch consist of a mixture of four isomers, alpha, beta, gamma, and delta. while all these isomers pose serious environmental problems, beta-hch is more problematic due to its longer persistence in the environment. we have studied the degradation of hch isomers by sphingomonas paucimobilis strain b90 and characterized the lin genes ... | 2002 | 12450824 |
| linking of microorganisms to phenanthrene metabolism in soil by analysis of (13)c-labeled cell lipids. | phenanthrene-metabolizing soil microbial communities were characterized by examining mineralization of [(14)c]phenanthrene, by most-probable-number (mpn) counting, by 16s-23s spacer dna analysis of the numerically dominant, culturable phenanthrene-degrading isolates, and by examining incorporation of [(13)c]phenanthrene-derived carbon into sterols and polar lipid fatty acids (plfas). an unpolluted agricultural soil, a roadside soil diffusely polluted with polycyclic aromatic hydrocarbons (pahs), ... | 2002 | 12450834 |
| characterization of tetrachlorohydroquinone reductive dehalogenase from sphingomonas sp. ug30. | tetrachlorohydroquinone reductive dehalogenase (pcpc) is the second of three enzymes that catalyze the initial degradation of pentachlorophenol in sphingomonas sp. ug30 and several other bacterial strains. the ug30 pcpc shares a high degree (94%) of primary sequence identity with the well-studied pcpc from sphingobium chlorophenolicum atcc 39723. significant differences, however, were observed between the two pcpc enzymes in some of their functional and kinetic properties. the temperature optimu ... | 2002 | 12459186 |
| occurrence of an alpha-galacturonosyl-ceramide in the dioxin-degrading bacterium sphingomonas wittichii. | the chemical structure of two glycosphingolipids (gsls) found in the dioxin-degrading bacterium sphingomonas wittichii strain rw1 was investigated by means of mass spectrometry and (1)h-nuclear magnetic resonance spectroscopy. one of the gsls was alpha-d-glucuronosyl-ceramide, commonly present in sphingomonas spp., and the other was proved to be alpha-d-galacturonosyl-ceramide, whose sugar configuration has not been reported before. in both gsls the ceramide portion was composed of myristic acid ... | 2002 | 12351245 |
| gellan gum biosynthesis in sphingomonas paucimobilis atcc 31461: genes, enzymes and exopolysaccharide production engineering. | the commercial gelling agent, gellan, is an extracellular polysaccharide (eps) produced by sphingomonas paucimobilis atcc 31461. in recent years, significant progress in understanding the relationship between gellan structure and properties and elucidation of the biosynthesis and engineering of this recent product of biotechnology has been made. this review focuses on recent advances in this field. emphasis is given to identification and characterization of genes and enzymes involved, or predict ... | 2002 | 12355314 |
| emendation of the genus sphingomonas yabuuchi et al. 1990 and junior objective synonymy of the species of three genera, sphingobium, novosphingobium and sphingopyxis, in conjunction with blastomonas ursincola. | the 16s rdna sequence similarities between the type strains of sphingomonas paucimobilis and 32 other sphingomonas species range from 90.2 to 99.6%. it might be possible to divide the genus into several new genera according to a dendrogram drawn from 16s rdna sequence similarity. however, the phenotypic and biochemical information needed to define clusters of strains representing distinct genera within this group of organisms was not previously available. although the cellular lipids of type str ... | 2002 | 12361250 |
| xenobiotics in the environment: present and future strategies to obviate the problem of biological persistence. | sustainable chemistry aims at an improved efficiency of using natural resources which are used to meet human needs for chemical products. chemists in science and industry, have become aware of the importance to design environmentally benign chemicals. one aspect is the biological persistence and the present paper reviews work in this field focussing on the degradation of xenobiotics in the environment. different structural reasons for chemical and biological persistence are described and strateg ... | 2002 | 11792455 |
| effects of different quinoid redox mediators on the anaerobic reduction of azo dyes by bacteria. | the addition of quinoid redox mediators to anaerobically incubated cultures of various taxonomically different bacterial species resulted in significantly increased reduction rates for the azo dye amaranth. from different quinones tested, generally anthraquinone-2-sulfonate (aqs) and lawsone (2-hydroxy-1,4-naphthoquinone) caused the highest increase in the azoreductase activities. the effects of aqs and lawsone were studied in greater detail with sphingomonas xenophaga bn6 and escherichia coli k ... | 2002 | 11999057 |
| binol-catalyzed highly enantioselective terminal alkyne additions to aromatic aldehydes. | [reaction: see text] the readily available binol ligand in combination with ti(o(i)pr)(4) was found to catalyze the highly enantioselective reaction (92-98% ee) of terminal alkynes with aromatic aldehydes that contain a variety of substituents and substitution patterns. after the preparation of the zinc acetylide reagent, the catalytic asymmetric addition to aldehydes proceeded at room temperature with excellent stereocontrol. this simple catalyst system is practical for the asymmetric synthesis ... | 2002 | 12027631 |
| practical syntheses of n-substituted 3-hydroxyazetidines and 4-hydroxypiperidines by hydroxylation with sphingomonas sp. hxn-200. | [reaction: see text] hydroxylation of n-substituted azetidines 11 and 12 and piperidines 15-19 with sphingomonas sp. hxn-200 gave 91-98% of the corresponding 3-hydroxyazetidines 13 and 14 and 4-hydroxypiperidines 20-24, respectively, with high activity and excellent regioselectivity. high yields and high product concentrations (2 g/l) were achieved with frozen/thawed cells as biocatalyst. for the first time, rehydrated lyophilized cells were successfully used for the biohydroxylation. | 2002 | 12027632 |
| prevalent bacterial species and novel phylotypes in advanced noma lesions. | the purpose of this study was to determine the bacterial diversity in advanced noma lesions using culture-independent molecular methods. 16s ribosomal dna bacterial genes from dna isolated from advanced noma lesions of four nigerian children were pcr amplified with universally conserved primers and spirochetal selective primers and cloned into escherichia coli. partial 16s rrna sequences of approximately 500 bases from 212 cloned inserts were used initially to determine species identity or close ... | 2002 | 12037085 |
| microbiota of periapical lesions refractory to endodontic therapy. | the periapical microbiota of 36 teeth with refractory apical periodontitis was investigated. none of the teeth had responded to conventional endodontic or long-term (> 6 months), calcium-hydroxide treatment. eight patients had received antibiotics systemically. after anaerobic culture, a total of 148 microbial strains were detected among 67 microbial species. one of the 36 lesions was culture-negative. approximately half (51.0%) of the bacterial strains were anaerobic. gram-positive species cons ... | 2002 | 12043869 |
| sphingomonas sp. strain ka1, carrying a carbazole dioxygenase gene homologue, degrades chlorinated dibenzo-p-dioxins in soil. | hybridization analysis showed that a newly isolated carbazole (car)-degrading bacterium sphingomonas sp. strain ka1 did not possess the gene encoding the terminal oxygenase component (caraa) of car 1,9a-dioxygenase at high homology (more than 90% identity) to that of another car-degrader, pseudomonas resinovorans strain ca10. however, pcr experiments using the primers for amplifying the internal fragment of the caraa gene (810 bp for strain ca10) showed that a pcr product of unexpected size (110 ... | 2002 | 12052549 |
| correction of the connecting vowel and gender of the specific epithet in the name sphingomonas macrogoltabidus takeuchi et al. 1993 to sphingomonas macrogolitabida. | in accordance with the bacteriological code (1990 revision), the connecting vowel and gender of the specific epithet macrogoltabidus in combination with the generic name sphingomonas must be -i- and the ending must be changed to -a to agree with the gender of the generic name, respectively. thus sphingomonas macroboltabidus takeuchi et al. 1993 should be sphingomonas macrogolitabida corrig. takeuchi et al. 1993. | 2002 | 12054221 |
| microbial diseases of corals and global warming. | coral bleaching and other diseases of corals have increased dramatically during the last few decades. as outbreaks of these diseases are highly correlated with increased sea-water temperature, one of the consequences of global warming will probably be mass destruction of coral reefs. the causative agent(s) of a few of these diseases have been reported: bleaching of oculina patagonica by vibrio shiloi; black band disease by a microbial consortium; sea-fan disease (aspergillosis) by aspergillus sy ... | 2002 | 12071977 |
| degradation of phenanthrene, methylphenanthrenes and dibenzothiophene by a sphingomonas strain 2mpii. | strain sphingomonassp. (2mpii), isolated from marine sediment, was able to utilize phenanthrene (p) or 2-methylphenanthrene (2mp) as the sole carbon source. however, 9-methylphenanthrene (9mp) and dibenzothiophene (dbt) were weakly degraded. the degradation rates of 9mp and dbt increased in the presence of 2mp, whilst the degradation rate of 2mp increased in the presence of 9mp. however, the presence of dbt inhibited the degradation of 2mp. dbt sulfone, a dbt metabolite, was not assimilated by t ... | 2002 | 12073136 |
| aerobic degradation of 2,4,6-trichlorophenol by a microbial consortium - selection and characterization of microbial consortium. | a microbial consortium that efficiently degrades 2,4,6-tcp (2,4,6-trichlorophenol), as the sole source of carbon and energy under aerobic conditions was selected from municipal activated sludge. six bacterial strains, designated s(1), s(2), s(3), s(4), s(5) and s(6), were isolated from the selected consortium and five were identified as sphingomonas paucimobilis (s(2), s(3)), burkholderia cepacia(s(4)), chryseomonas luteola (s(5)) and vibrio metschnikovii (s(6)). after prolonged cultivation foll ... | 2002 | 12073141 |
| growth in coculture stimulates metabolism of the phenylurea herbicide isoproturon by sphingomonas sp. strain srs2. | metabolism of the phenylurea herbicide isoproturon by sphingomonas sp. strain srs2 was significantly enhanced when the strain was grown in coculture with a soil bacterium (designated strain srs1). both members of this consortium were isolated from a highly enriched isoproturon-degrading culture derived from an agricultural soil previously treated regularly with the herbicide. based on analysis of the 16s rrna gene, strain srs1 was assigned to the beta-subdivision of the proteobacteria and probab ... | 2002 | 12089031 |
| use of a two-phase partitioning bioreactor for degrading polycyclic aromatic hydrocarbons by a sphingomonas sp. | a two-phase partitioning bioreactor (tppb) utilizing the bacterium sphingomonas aromaticivorans b0695 was used to degrade four low molecular weight (lmw) polycyclic aromatic hydrocarbons (pahs). the tppb concept is based on the use of a biocompatible, immiscible organic solvent in which high concentrations of recalcitrant substrates are dissolved. these substances partition into the cell-containing aqueous phase at rates determined by the metabolic activity of the cells. experiments showed that ... | 2002 | 12111172 |
| cadmium biosorption by sphingomonas paucimobilis biomass. | among microorganisms isolated in bangkok, the gram-negative bacterium sphingomonas paucimobilis exhibited the greatest cadmium tolerance. it was able to survive in the medium containing cadmium as high as 200 mg/l. however, concentrations of cadmium at 25-200 mg/l inhibited its growth. the biosorption properties for cadmium of this bacterial biomass and the effects of environmental factors (i.e., biosorbent type, initial ph and biosorbent concentration) on the cadmium biosorption were explored. ... | 2002 | 12146636 |
| organization and regulation of pentachlorophenol-degrading genes in sphingobium chlorophenolicum atcc 39723. | the first three enzymes of the pentachlorophenol (pcp) degradation pathway in sphingobium chlorophenolicum (formerly sphingomonas chlorophenolica) atcc 39723 have been characterized, and the corresponding genes, pcpa, pcpb, and pcpc, have been individually cloned and sequenced. to search for new genes involved in pcp degradation and map the physical locations of the pcp genes, a 24-kb fragment containing pcpa and pcpc was completely sequenced. a putative lysr-type transcriptional regulator gene, ... | 2002 | 12169590 |
| characterization of four olive-mill-wastewater indigenous bacterial strains capable of aerobically degrading hydroxylated and methoxylated monocyclic aromatic compounds. | seven aerobic bacterial strains capable of degrading several of the monocyclic aromatic compounds occurring in the phenolic fraction of olive-mill wastewaters (omws) were isolated from an italian omw. the results of the 16s rdna restriction analysis evidenced that these strains are distributed among four different groups. one strain of each group was taxonomically characterized by sequencing the amplified 16s rdna, and the four strains were assigned to the genera comamonas (strain av1a), ralston ... | 2002 | 12189422 |
| identification of quinoide redox mediators that are formed during the degradation of naphthalene-2-sulfonate by sphingomonas xenophaga bn6. | during aerobic degradation of naphthalene-2-sulfonate (2ns), sphingomonas xenophaga strain bn6 produces redox mediators which significantly increase the ability of the strain to reduce azo dyes under anaerobic conditions. it was previously suggested that 1,2-dihydroxynaphthalene (1,2-dhn), which is an intermediate in the degradative pathway of 2ns, is the precursor of these redox mediators. in order to analyze the importance of the formation of 1,2-dhn, the dihydroxynaphthalene dioxygenase gene ... | 2002 | 12200285 |
| characterization of the 5-carboxyvanillate decarboxylase gene and its role in lignin-related biphenyl catabolism in sphingomonas paucimobilis syk-6. | sphingomonas paucimobilis syk-6 degrades a lignin-related biphenyl compound, 5,5'-dehydrodivanillate (ddva), to 5-carboxyvanillate (5cva) by the enzyme reactions catalyzed by the ddva o-demethylase (ligx), the ring cleavage oxygenase (ligz), and the meta-cleavage compound hydrolase (ligy). in this study we examined the degradation step of 5cva. 5cva was transformed to vanillate, o-demethylated, and further degraded via the protocatechuate 4,5-cleavage pathway by this strain. a cosmid clone which ... | 2002 | 12200294 |
| cloning and characterization of the ferulic acid catabolic genes of sphingomonas paucimobilis syk-6. | sphingomonas paucimobilis syk-6 degrades ferulic acid to vanillin, and it is further metabolized through the protocatechuate 4,5-cleavage pathway. we obtained a tn5 mutant of syk-6, fa2, which was able to grow on vanillic acid but not on ferulic acid. a cosmid which complemented the growth deficiency of fa2 on ferulic acid was isolated. the 5.2-kb bamhi-ecori fragment in this cosmid conferred the transformation activity of ferulic acid to vanillin on escherichia coli host cells. a sequencing ana ... | 2002 | 12200295 |
| evidence for natural horizontal transfer of the pcpb gene in the evolution of polychlorophenol-degrading sphingomonads. | the chlorophenol degradation pathway in sphingobium chlorophenolicum is initiated by the pcpb gene product, pentachlorophenol-4-monooxygenase. the distribution of the gene was studied in a phylogenetically diverse group of polychlorophenol-degrading bacteria isolated from contaminated groundwater in kärkölä, finland. all the sphingomonads isolated were shown to share pcpb gene homologs with 98.9 to 100% sequence identity. the gene product was expressed when the strains were induced by 2,3,4,6-te ... | 2002 | 12200305 |
| biotransformation of p-xylene and 2,6-dimethylnaphthalene by xylene monooxygenase cloned from a sphingomonas isolate. | sphingomonas strain asu1 was isolated from an industrial wastewater bioreactor and grew on 2,6-dimethylnaphthalene (2,6-dmn) as the sole carbon/energy source. the genes for a xylene monooxygenase were cloned from strain asu1. expression of the asu1 xylene monooxygenase was compared to expression of the pwwo xylene monooxygenase in escherichia coli. both monooxygenases transformed p-xylene and 2,6-dmn by initially hydroxylating one methyl group. in addition, the asu1 monooxygenase also hydroxylat ... | 2002 | 12226724 |
| isolation and characterization of sphingomonas sp. gtin11 capable of carbazole metabolism in petroleum. | a bacterial culture was isolated from a manufactured gas plant (mgp) soil based on its ability to metabolize the nitrogen-containing heterocycle carbazole. the culture was identified as a sphingomonas sp. and was given the designation gtin11. a cloned 4.2kb dna fragment was confirmed to contain genes responsible for carbazole degradation. dna sequence analysis revealed that the fragment contained five open reading frames (orfs) with the deduced amino acid sequence showing homology to; carbazole ... | 2002 | 12237109 |
| a super-channel in bacteria: macromolecule uptake and depolymerization systems of sphingomonas sp. a1 with a special cell surface structure. | 2002 | 12520874 | |
| sphingopyxis witflariensis sp. nov., isolated from activated sludge. | classification of strain w-50(t), which was isolated from a wastewater treatment plant, was investigated by a polyphasic approach. cells of strain w-50(t) were gram-negative, strictly aerobic, oxidase-positive and yellow-pigmented. ubiquinone q-10 was the main respiratory lipoquinone system and polar lipid fingerprints were characterized by the presence of a sphingoglycolipid, suggesting that strain w-50(t) belongs to the alpha-4 subclass of the proteobacteria. sequencing and comparative analyse ... | 2002 | 12508864 |
| sphingomonas melonis sp. nov., a novel pathogen that causes brown spots on yellow spanish melon fruits. | a polyphasic taxonomic study was performed on the phytopathogenic bacterial strains dapp-pg 224(t) and dapp-pg 228, which cause brown spot on yellow spanish melon (cucumis melo var. inodorus) fruits. based on the presence of glucuronosyl ceramide (sgl-1) in cellular lipids, the results of fatty acid analysis and 16s rdna sequence comparison, the strains had been identified as belonging to the genus sphingomonas and as phylogenetically related to sphingomonas mali, sphingomonas pruni and sphingom ... | 2002 | 12508872 |
| diversity of 746 heterotrophic bacteria isolated from microbial mats from ten antarctic lakes. | microbial mats, growing in antarctic lakes constitute unique and very diverse habitats. in these mats microorganisms are confronted with extreme life conditions. we isolated 746 bacterial strains from mats collected from ten lakes in the dry valleys (lakes hoare and fryxell), the vestfold hills (lakes ace, druzhby, grace, highway, pendant, organic and watts) and the larsemann hills (lake reid), using heterotrophic growth conditions. these strains were investigated by fatty acid analysis, and by ... | 2002 | 12583721 |
| novel 2,4-dichlorophenoxyacetic acid degradation genes from oligotrophic bradyrhizobium sp. strain hw13 isolated from a pristine environment. | the tfd genes of ralstonia eutropha jmp134 are the only well-characterized set of genes responsible for 2,4-dichlorophenoxyacetic acid (2,4-d) degradation among 2,4-d-degrading bacteria. a new family of 2,4-d degradation genes, cadrabkc, was cloned and characterized from bradyrhizobium sp. strain hw13, a strain that was isolated from a buried hawaiian soil that has never experienced anthropogenic chemicals. the cadr gene was inferred to encode an arac/xyls type of transcriptional regulator from ... | 2002 | 11751829 |
| molecular structure of the rhamsan-like exocellular polysaccharide rmdp17 from sphingomonas paucimobilis. | x-ray diffraction analysis of the sodium salt of the polysaccharide rmdp17, a 2-deoxy rhamsan analog, reveals that it adopts a gellan-like, half-staggered, threefold, left handed, double helix of pitch 57.4 a. the side chain of the branched polymer is hydrogen bonded to the main chain. sodium ions, linked to the carboxylate groups, promote the association of helices via water molecules. two helices of opposite polarity occupy a trigonal unit cell of dimensions a=17.6 and c=28.7 a. the packing ar ... | 2002 | 11755911 |
| isolation and initial characterization of a bacterial consortium able to mineralize fluorobenzene. | fluorinated compounds are known to be more resistant to microbial degradation than other halogenated chemicals. a microbial consortium capable of aerobic biodegradation of fluorobenzene (fb) as the sole source of carbon and energy was isolated by selective enrichment from sediments collected in a drain near an industrial site. a combination of three microbial strains recovered from the enriched consortium was shown to be necessary for complete fb mineralization. two of the strains (f1 and f3) we ... | 2002 | 11772615 |
| enzymatic reaction of hydrogen peroxide-dependent peroxygenase cytochrome p450s: kinetic deuterium isotope effects and analyses by resonance raman spectroscopy. | cytochromes p450sp(alpha) (cyp152b1) and p450bs(beta) (cyp152a1), which are isolated from sphingomonas paucimobilis and bacillus subtilis, respectively, belong to the p450 superfamily, but catalyze hydroxylation reactions, in which an oxygen atom from h2o2 is efficiently introduced into fatty acids (e.g., myristic acid). p450sp(alpha) produces the alpha-hydroxylated (alpha-oh) products at 100%, while p450bs(beta) produces alpha- and beta-hydroxylated (beta-oh) products at 33 and 67%, respectivel ... | 2002 | 11827534 |
| aerobic and facultatively anaerobic cellulolytic bacteria from the gut of the termite zootermopsis angusticollis. | to demonstrate the occurrence of cellulolytic bacteria in the termite zootermopsis angusticollis. | 2002 | 11849325 |
| employment of the human estrogen receptor beta ligand-binding domain and co-activator src1 nuclear receptor-binding domain for the construction of a yeast two-hybrid detection system for endocrine disrupters. | to screen a wide variety of chemicals for endocrine disrupters, and to develop an effective microbial degradation system for them, a good system is needed for the rapid and accurate evaluation of the endocrine-disrupting activities of suspected chemicals and their degradation products. we constructed two-hybrid systems that co-express the gal4p dna binding domain/ligand-binding domain of human estrogen receptor (her) alpha or beta and the gal4p transactivation domain/nuclear receptor-binding dom ... | 2002 | 11872169 |
| molecular detection and diversity of polycyclic aromatic hydrocarbon-degrading bacteria isolated from geographically diverse sites. | nineteen polycyclic aromatic hydrocarbon (pah)-degrading bacteria were isolated from environmental samples in kuwait, indonesia, thailand, and japan by enrichment with either naphthalene or phenanthrene as a sole carbon source. sequence analyses of the 16-s rrna gene indicated that at least seven genera (ralstonia, sphingomonas, burkholderia, pseudomonas, comamonas, flavobacterium, and bacillus) were present in this collection. determination of the ability of the isolates to use pah and its pres ... | 2002 | 11876413 |
| crystal structure of algq2, a macromolecule (alginate)-binding protein of sphingomonas sp. a1 at 2.0a resolution. | sphingomonas sp. a1 possesses a high molecular mass (average 25,700 da) alginate uptake system mediated by a novel pit-dependent abc transporter. the x-ray crystallographic structure of algq2 (57,200 da), an alginate-binding protein in the system, was determined by the multiple isomorphous replacement method and refined at 2.0 a resolution with a final r-factor of 18.3% for 15 to 2.0 a resolution data. the refined structure of algq2 was comprised of 492 amino acid residues, 172 water molecules, ... | 2002 | 11884143 |
| recurrent sphingomonas paucimobilis -bacteraemia associated with a multi-bacterial water-borne epidemic among neutropenic patients. | a cluster of septicaemias due to several water-related species occurred in a haematological unit of a university hospital. in recurrent septicaemias of a leukaemic patient caused by sphingomonas paucimobilis, genotyping of the blood isolates by use of random amplified polymorphic dna-analysis verified the presence of two distinct s. paucimobilis strains during two of the separate episodes. a strain of s. paucimobilis identical to one of the patient's was isolated from tap water collected in the ... | 2002 | 11886195 |
| nonionic surfactant effects on pentachlorophenol biodegradation. | several potential mechanisms of surfactant-induced inhibition of pentachlorophenol (pcp) biodegradation were tested using a pure bacterial culture of sphingomonas chlorophenolicum sp. strain ra2. pcp degradation, glucose degradation, and oxygen uptake during endogenous conditions and during glucose degradation were measured for batch systems in the presence of the nonionic surfactant tergitol np-10 (tnp10). tnp10 did not exert toxicity on ra2 as measured by dissolved oxygen uptake rates under en ... | 2002 | 11902780 |
| recycle use of sphingomonas sp. cdh-7 cells for continuous degradation of carbazole in the presence of mgcl2. | carbazole (ca) is a heterocyclic nitrogen compound contained in the crude petroleum oil and recalcitrant to removal through the refinery processes. for development of the efficient ca-degradation bioprocess, conditions for the recycle use of sphingomonas sp. cdh-7 resting cells were examined. when the resting cells (o.d.(660) 3.3) were shaken in 50 m m k2hpo4-kh2po4 buffer (ph 7.0) containing ca 1000 mg/l, ca 880 mg/l was degraded within 3 h, but thereafter the activity decreased markedly. howev ... | 2002 | 11910494 |
| cloning and characterization of linr, involved in regulation of the downstream pathway for gamma-hexachlorocyclohexane degradation in sphingomonas paucimobilis ut26. | in sphingomonas paucimobilis ut26, lind and line activities, which are responsible for the degradation of gamma-hexachlorocyclohexane, are inducibly expressed in the presence of their substrates, 2,5-dichlorohydroquinone (2,5-dchq) and chlorohydroquinone (chq). the nucleotide sequence of the 1-kb upstream region of the line gene was determined, and an open reading frame (orf) was found in divergent orientation from line. because the putative protein product of the orf showed similarity to the ly ... | 2002 | 11916699 |
| identification of mouse submaxillary gland protein in mouse saliva and its binding to mouse oral bacteria. | the mouse submaxillary gland protein (msmgp) is highly expressed in the submandibular gland of the adult mouse and rat. it shares 51% identity at the amino-acid level with a human protein, the prolactin-inducible protein (pip)/gross cystic disease fluid protein 15 (gcdfp-15), which has been found in saliva, tears, sweat, seminal plasma, submucosal glands of the lung and amniotic fluid. more recently, the human pip has been reported to bind to bacterial strains normally found in the mouth, ear ca ... | 2002 | 11922875 |
| exploring the structure and activity of haloalkane dehalogenase from sphingomonas paucimobilis ut26: evidence for product- and water-mediated inhibition. | the hydrolysis of haloalkanes to their corresponding alcohols and inorganic halides is catalyzed by alpha/beta-hydrolases called haloalkane dehalogenases. the study of haloalkane dehalogenases is vital for the development of these enzymes if they are to be utilized for bioremediation of organohalide-contaminated industrial waste. we report the kinetic and structural analysis of the haloalkane dehalogenase from sphingomonas paucimobilis ut26 (linb) in complex with each of 1,2-dichloroethane and 1 ... | 2002 | 11939779 |
| degradation of polycyclic aromatic hydrocarbons dissolved in tween 80 surfactant solutions by sphingomonas paucimobilis epa 505. | the degradation rates of mixtures of pyrene (pyr), fluoranthene (fla), and phenanthrene (phe) by sphingomonas paucimobilis epa 505 were measured in the presence of the nonionic surfactant tween 80. for strain epa 505, fla and phe are growth substrates, while pyr is not. linear degradation rates ranging from 0.05 to 2.2 mg x l(-1) x h(-1) were observed for fla, pyr, and phe at approximately 10(7) colony-forming units (cfu)/ml. at lower biomass, pyr degradation exhibited lognormal degradation. the ... | 2002 | 11958568 |
| isolation and characterization of dibenzofuran-degrading bacteria. | two bacterial strains capable of utilizing dibenzofuran (df) as a sole carbon source were isolated from soil samples of reclaimed land. the strains designated hl1 and hl7 were identified as klebsiella sp. and sphingomonas sp., respectively, on the basis of biochemical characteristics and the sequences of the 16s ribosomal dna. sphingomonas sp. strain hl7 degraded non-, mono- and also dichlorinated df and dibenzo-p-dioxin (dd). klebsiella sp. strain hl1 was able to degrade non- and monochlorinate ... | 2002 | 11959434 |
| extracellular polysaccharides of rhodococcus rhodochrous s-2 stimulate the degradation of aromatic components in crude oil by indigenous marine bacteria. | rhodococcus rhodochrous s-2 produces extracellular polysaccharides (s-2 eps) containing d-glucose, d-galactose, d-mannose, d-glucuronic acid, and lipids, which is important to the tolerance of this strain to an aromatic fraction of (af) arabian light crude oil (n. iwabuchi, n. sunairi, h. anzai, m. nakajima, and s. harayama, appl. environ. microbiol. 66:5073-5077, 2000). in the present study, we examined the effects of s-2 eps on the growth of indigenous marine bacteria on af. indigenous bacteri ... | 2002 | 11976106 |
| biotransformation of 2,7-dichloro- and 1,2,3,4-tetrachlorodibenzo-p-dioxin by sphingomonas wittichii rw1. | aerobic biotransformation of the diaryl ethers 2,7-dichlorodibenzo-p-dioxin and 1,2,3,4-tetrachlorodibenzo-p-dioxin by the dibenzo-p-dioxin-utilizing strain sphingomonas wittichii rw1, producing corresponding metabolites, was demonstrated for the first time. our strain transformed 2,7-dichlorodibenzo-p-dioxin, yielding 4-chlorocatechol, and 1,2,3,4-tetrachlorodibenzo-p-dioxin, producing 3,4,5,6-tetrachlorocatechol and 2-methoxy-3,4,5,6-tetrachlorophenol; all of these compounds were unequivocally ... | 2002 | 11976140 |
| characterization of sphingomonas sp. ant 17, an aromatic hydrocarbon-degrading bacterium isolated from antarctic soil. | sphingomonas sp. strain ant 17 was isolated from fuel-contaminated soil collected at scott base, ross island, antarctica. we anticipated that ant 17 would be a good model organism for studying cold climate bioremediation, and therefore determined its biodegradation capabilities and tolerance of potentially growth-limiting environmental conditions. sphingomonas sp. ant 17 degrades the aromatic fraction of several different crude oils, jet fuel, and diesel fuel at low temperatures and without nutr ... | 2002 | 11984628 |
| a kinetic model for surfactant inhibition of pentachlorophenol biodegradation. | a kinetic model is used to describe the effect of the nonionic surfactant tergitol np-10 (tnp10) on pentachlorophenol (pcp) biodegradation by sphingomonas chlorophenolica sp. strain ra2. different initial biomass to initial substrate ratios ranging from 13 to 418 were tested with 23 tnp10 concentrations ranging from 0 to 1500 mg/l. tests were also conducted at 10 degrees c and 20 degrees c. no pcp biodegradation inhibition was observed at concentrations below the critical micelle concentration ( ... | 2002 | 11992526 |
| degradation of 2,3,4,6-tetrachlorophenol at low temperature and low dioxygen concentrations by phylogenetically different groundwater and bioreactor bacteria. | effects of low temperature and low oxygen partial pressure on the occurrence and activity of 2,3,4,6-tetrachlorophenol degrading bacteria in a boreal chlorophenol contaminated groundwater and a full-scale fluidized-bed bioreactor were studied using four polychlorophenol degrading bacterial isolates of different phylogenetic backgrounds. these included an alpha-proteobacterial sphingomonas sp. strain mt1 isolated from the full-scale bioreactor and three isolates from the contaminated groundwater ... | 2001 | 11995822 |
| [the application of genetic engineering to the petroleum biodesulfurization]. | the developed course and reaction mechanisms of petroleum biodesulfurization were introduced. the recent development of genetic engineering technology, which used in desulfuration strain's construction, reconstruction and other fields, was summarized emphatically. its current research situation internal and overseas and the developing prospect were simply analyzed, and our research designs were submitted. | 2001 | 11910751 |
| purification and characterization of poly(aspartic acid) hydrolase from sphingomonas sp. kt-1. | poly(aspartic acid) (paa) hydrolase was purified from sphingomonas sp. kt-1 (jcm10459). the purified hydrolase degraded thermally synthesized paa to oligomers. the molecular mass of paa hydrolase was 30 kda and the isoelectric point was 8.9. the optimum values of ph and temperature for paa degradation were 10.0 and 40 degrees c, respectively. the investigation of the effect of inhibitors for the paa-degrading activities has revealed that the paa hydrolase is a serine-type hydrolase. the structur ... | 2001 | 11777387 |
| basic examinations on chemical pre-oxidation by ozone for enhancing bioremediation of phenanthrene contaminated soils. | biological treatment of polycyclic aromatic hydrocarbons (pah) has been demonstrated to be a feasible and common remediation technology which has been successfully applied to the clean-up of contaminated soils. because bioavailability of the contaminants is of great importance for a successful bioremediation, a chemical pre-oxidation step by ozone was tested to enhance the subsequent biodegradation steps. oxidation of pah by ozone should result in reaction products that have a better solubility ... | 2001 | 11778897 |
| microbial populations associated with the reduction and enhanced mobilization of arsenic in mine tailings. | microbial reduction of arsenate [as(v)] to arsenite [as(iii)] and the subsequent effects on as mobilization in contaminated mine tailings were studied under transport conditions. molecular analysis of bacterial populations and traditional isolation techniques were used in conjunction with column experiments designed to observe relationships among ph (limed vs unlimed treatments), redox potential (pt electrode), and mobilization of as. liming increased ph values from approximately 4 to 8, resulti ... | 2001 | 11783644 |
| structure-specificity relationships for haloalkane dehalogenases. | a structural analysis of the substrate specificity of hydrolytic dehalogenases originating from three different bacterial isolates has been performed using the multiple computer-automated structure evaluation methodology. this methodology identifies structural fragments in substrate molecules that either activate or deactivate biological processes. the analysis presented in this contribution is based on newly measured dehalogenation data combined with data from the literature (91 substrates). th ... | 2001 | 11764149 |
| a transcriptional luxab reporter fusion responding to fluorene in sphingomonas sp. lb126 and its initial characterisation for whole-cell bioreporter purposes. | the promoter probe mini-tn5-luxab-tet was used to create a luxab transcriptional fusion responding to fluorene in the fluorene utilising bacterium sphingomonas sp. lb126. the mutant strain, named l-132, was impaired in fluorene utilisation and strongly emitted light upon addition of fluorene to the growth medium. l-132 was initially characterised and examined for its potential use as a whole-cell biosensor in the perspective of quantifying fluorene in environmental samples. activity of the repor ... | 2001 | 11766960 |
| fluorene degradation by sphingomonas sp. lb126 proceeds through protocatechuic acid: a genetic analysis. | sphingomonas sp. lb126 is able to utilize fluorene as sole source of carbon and energy. in the present study, a mutagenic vector was constructed and a "plasmid rescue" strategy was set up to isolate a 16.5-kb dna fragment containing genes required for fluorene degradation. a 14.5-kb portion of the cloned dna was sequenced revealing thirteen open reading frames. two encoded hypothetical proteins (flde and fldy) similar to transcriptional regulators and one (orf360) located on an is-like element ( ... | 2001 | 11766961 |
| streptomyces aureofaciens sporulation-specific sigma factor sigma(rpoz) directs expression of a gene encoding protein similar to hydrolases involved in degradation of the lignin-related biphenyl compounds. | a previously established method for the identification of promoters recognized by a heterologous rna polymerase holoenzyme containing a particular sigma factor was used to identify promoters dependent upon a sporulation specific sigma factor, sigma(rpoz), of streptomyces aureofaciens. three new positive dna fragments were identified, and these putative rpoz-dependent promoters, p(ren24), p(ren57), and p(ren71), contained sequences similar to the consensus sequence of flagellar and chemotaxis pro ... | 2001 | 11766963 |
| characterisation of a gene cluster involved in bacterial degradation of the cyanobacterial toxin microcystin lr. | a novel pathway for degradation of the cyanobacterial heptapeptide hepatotoxin microcystin lr was identified in a newly isolated sphingomonas sp. (bourne et al. 1996 appl. environ. microbiol. 62: 4086-4094). we now report the cloning and molecular characterisation of four genes from this sphingomonas sp. that exist on a 5.8-kb genomic fragment and encode the three hydrolytic enzymes involved in this pathway together with a putative oligopeptide transporter. the heterologously expressed degradati ... | 2001 | 11769251 |
| sphingomonas alaskensis sp. nov., a dominant bacterium from a marine oligotrophic environment. | seven gram-negative strains, isolated in 1990 from a 10(6)-fold dilution series of seawater from resurrection bay, a deep fjord of the gulf of alaska, were identified in a polyphasic taxonomic study. analysis of 16s rdna sequences and dna-homology studies confirmed the phylogenetic position of all strains in the genus sphingomonas and further indicated that all of the strains constitute a single homogeneous genomic species, distinct from all validly described sphingomonas species. the ability to ... | 2001 | 11211276 |
| evaluation of bacteria isolated from rice for plant growth promotion and biological control of seedling disease of rice. | of 102 rhizoplane and endophytic bacteria isolated from rice roots and stems in california, 37% significantly (p < or = 0.05) inhibited the growth in vitro of two pathogens, achlya klebsiana and pythium spinosum, causing seedling disease of rice. four endophytic strains were highly effective against seedling disease in growth pouch assays, and these were identified as pseudomonas fluorescens (s3), pseudomonas tolaasii (s20), pseudomonas veronii (s21), and sphingomonas trueperi (s12) by sequencin ... | 2001 | 11718545 |
| isolation from agricultural soil and characterization of a sphingomonas sp. able to mineralize the phenylurea herbicide isoproturon. | a soil bacterium (designated strain srs2) able to metabolize the phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (ipu), was isolated from a previously ipu-treated agricultural soil. based on a partial analysis of the 16s rrna gene and the cellular fatty acids, the strain was identified as a sphingomonas sp. within the alpha-subdivision of the proteobacteria. strain srs2 was able to mineralize ipu when provided as a source of carbon, nitrogen, and energy. supplementing th ... | 2001 | 11722885 |
| super-channel in bacteria: function and structure of the macromolecule import system mediated by a pit-dependent abc transporter. | in a soil isolate, sphingomonas sp. a1, the transport of a macromolecule (alginate: 27 kda) is mediated by a pit-dependent atp-binding cassette (abc) transporter. the transporter is different from other abc transporters so far analyzed in that its function is dependent on a pit, a mouth-like organ formed on the cell surface only when cells are compelled to assimilate macromolecules, and in that it allows direct import of macromolecules into cells. the abc transporter coupled with the pit, which ... | 2001 | 11731126 |
| preparation of (r)- and (s)-n-protected 3-hydroxypyrrolidines by hydroxylation with sphingomonas sp. hxn-200, a highly active, regio- and stereoselective, and easy to handle biocatalyst. | hydroxylation of n-benzylpyrrolidine 8 with resting cells of sphingomonas sp. hxn-200 gave n-benzyl-3-hydroxypyrrolidine 15 in 53% ee (s) with an activity of 5.8 u/g cdw. by changing the "docking/protecting group" in pyrrolidines, hydroxylation activity and enantioselectivity were further improved and the enantiocomplementary formation of 3-hydroxypyrrolidines was achieved: hydroxylation of n-benzoyl-, n-benzyloxycarbonyl-, n-phenoxycarbonyl-, and n-tert-butoxycarbonyl-pyrrolidines 9-12 gave the ... | 2001 | 11735520 |
| identification of protein fold and catalytic residues of gamma-hexachlorocyclohexane dehydrochlorinase lina. | gamma-hexachlorocyclohexane dehydrochlorinase (lina) is a unique dehydrochlorinase that has no homologous sequence at the amino acid-sequence level and for which the evolutionary origin is unknown. we here propose that lina is a member of a novel structural superfamily of proteins containing scytalone dehydratase, 3-oxo-delta(5)-steroid isomerase, nuclear transport factor 2, and the beta-subunit of naphthalene dioxygenase-all known structures with different functions. the catalytic and the activ ... | 2001 | 11746694 |
| reaction mechanism and stereochemistry of gamma-hexachlorocyclohexane dehydrochlorinase lina. | gamma-hexachlorocyclohexane dehydrochlorinase (lina) catalyzes the initial steps in the biotransformation of the important insecticide gamma-hexachlorocyclohexane (gamma-hch) by the soil bacterium sphingomonas paucimobilis ut26. stereochemical analysis of the reaction products formed during conversion of gamma-hch by lina was investigated by gc-ms, nmr, cd, and molecular modeling. the nmr spectra of 1,3,4,5,6-pentachlorocyclohexene (pcch) produced from gamma-hch using either enzymatic dehydrochl ... | 2001 | 11099497 |
| alpha- and beta-proteobacteria control the consumption and release of amino acids on lake snow aggregates. | we analyzed the composition of aggregate (lake snow)-associated bacterial communities in lake constance from 1994 until 1996 between a depth of 25 m and the sediment surface at 110 m by fluorescent in situ hybridization with rrna-targeted oligonucleotide probes of various specificity. in addition, we experimentally examined the turnover of dissolved amino acids and carbohydrates together with the microbial colonization of aggregates formed in rolling tanks in the lab. generally, between 40 and m ... | 2001 | 11157226 |
| biochemical characterization of broad-specificity enzymes using multivariate experimental design and a colorimetric microplate assay: characterization of the haloalkane dehalogenase mutants. | the ph indicator dye-based colorimetric method and multivariate experimental design were used for the systematic biochemical characterization of the broad-specificity enzymes haloalkane dehalogenases. halogenated compounds for characterization of the enzymes were selected using principal component analysis. the substrates were characterised by 24 physico-chemical and structural descriptors. thirty-four substrates were selected for testing out of 194 halogenated compounds. relative activities det ... | 2001 | 11165344 |
| new broad-host-range promoter probe vectors based on the plasmid rk2 replicon. | broad-host-range plasmid rk2-based promoter probe vectors with a known nucleotide sequence were constructed. in the absence of an upstream promoter, the expression of two tested reporter genes (luc and lacz) in escherichia coli was virtually zero, while insertion of the ptrc promoter resulted in strong inducer-dependent expression. the lacz-based vectors were mobilized into pseudomonas fluorescens st, pseudomonas putida kt2442, sphingomonas spp. and burkholderia spp. lb400, and expression analys ... | 2001 | 11167001 |
| a simple and easy method for the monitoring of environmental pollutants using oligotrophic bacteria. | sphingomonas paucimobilis kps01, an oligotrophic bacterium isolated from soil, may be a useful tool for monitoring heavy metals. previous methods relying on counting of viable cells require a relatively long time and some skill; we have developed a method based on optical density (o.d.) measurements which is significantly faster and does not require skilled personnel. the results of the o.d. and viable count methods were consistent; both methods detected heavy metals at concentrations ranging fr ... | 2001 | 11169034 |
| growth of a bacterial consortium on triclosan. | triclosan is a polychlorinated hydroxy diphenylether that has been widely used as an antimicrobial compound. an enrichment using triclosan as a sole source of carbon and energy yielded a consortium of bacteria capable of growing on this compound. the dichloro ring was partially mineralized, resulting in the conversion of approximately 35% of the [(14)c]triclosan to [(14)c]co(2). use of molecular fingerprinting techniques and 16s rdna cloning and sequencing aided in the identification and eventua ... | 2001 | 11451514 |
| phosphorus-31 nuclear magnetic resonance study of the effect of pentachlorophenol (pcp) on the physiologies of pcp-degrading microorganisms. | free and agarose-encapsulated pentachlorophenol (pcp)-degrading sphingomonas sp. isolates ug25 and ug30 were compared to sphingomonas chlorophenolica atcc 39723 with respect to the ability to degrade pcp. pretreatment of the ug25 and ug30 strains with 50 microg of pcp per ml enabled the cells to subsequently degrade higher levels of this environmental pollutant. similar treatment of atcc 39723 cells had no effect on the level of pcp degraded by this strain. phosphorus-31 nuclear magnetic resonan ... | 2001 | 11472931 |