| soluble methane monooxygenase component b gene probe for identification of methanotrophs that rapidly degrade trichloroethylene. | restriction fragment length polymorphisms, western blot (immunoblot) analysis, and fluorescence-labelled signature probes were used for the characterization of methanotrophic bacteria as well as for the identification of methanotrophs which contained the soluble methane monooxygenase (mmo) gene and were able to degrade trichloroethylene (tce). the gene encoding a soluble mmo component b protein from methylosinus trichosporium ob3b was cloned. it contained a 2.2-kb ecori fragment. with this clone ... | 1992 | 1349468 |
| characterization of a methane-utilizing bacterium from a bacterial consortium that rapidly degrades trichloroethylene and chloroform. | a mixed culture of bacteria grown in a bioreactor with methane as a carbon and energy source rapidly oxidized trichloroethylene and chloroform. the most abundant organism was a crescent-shaped bacterium that bound the fluorescent oligonucleotide signature probes that specifically hybridize to serine pathway methylotrophs. the 5s rrna from this bacterium was found to be 93.5% homologous to the methylosinus trichosporium ob3b 5s rna sequence. a type ii methanotrophic bacterium, isolated in pure cu ... | 1992 | 1377902 |
| hydrodynamic effects on microcapillary motility and chemotaxis assays of methylosinus trichosporium ob3b. | a study of the random motility and chemotaxis of methylosinus trichosporium ob3b was conducted by using palleroni-chamber microcapillary assay procedures. under the growth conditions employed, this methanotroph was observed qualitatively with a microscope to be either slightly motile or essentially nonmotile. however, the cells did not not respond in the microcapillary assays in the manner expected for nonmotile brownian particles. as a consequence, several hydrodynamic effects on these palleron ... | 1992 | 1444383 |
| applications of a colorimetric plate assay for soluble methane monooxygenase activity. | a straightforward method is described for screening methanotrophic colonies for soluble methane monooxygenase (smmo) activity on solid media. such activity results in the development of a colored complex between 1-naphthol, which is formed when smmo reacts with naphthalene, and o-dianisidine (tetrazotized). methanotrophic colonies expressing smmo turned deep purple when exposed successively to naphthalene and o-dianisidine. the method was evaluated within the contexts of two potential applicatio ... | 1992 | 1637160 |
| fate of 2,2,2-trichloroacetaldehyde (chloral hydrate) produced during trichloroethylene oxidation by methanotrophs. | four different methanotrophs expressing soluble methane monooxygenase produced 2,2,2-trichloroacetaldehyde, or chloral hydrate, a controlled substance, during the oxidation of trichloroethylene. chloral hydrate concentrations decreased in these cultures between 1 h and 24 h of incubation. chloral hydrate was shown to be biologically transformed to trichloroethanol and trichloroacetic acid by methylosinus trichosporium ob3b. at elevated ph and temperature, chloral hydrate readily decomposed and c ... | 1991 | 1768109 |
| kinetics of chlorinated hydrocarbon degradation by methylosinus trichosporium ob3b and toxicity of trichloroethylene. | the kinetics of the degradation of trichloroethylene (tce) and seven other chlorinated aliphatic hydrocarbons by methylosinus trichosporium ob3b were studied. all experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. compounds that were readily degraded included chloroform, trans-1,2-dichloroethylene, and tce, with vmax values of 550, 330, and 290 nmol min-1 mg of cells-1, respectively. 1,1-dichloroethylene was a very poor substrate. t ... | 1991 | 2036023 |
| oxidation of aromatic alcohols by purified methanol dehydrogenase from methylosinus trichosporium. | methanol dehydrogenase was found to be present in subcellular preparations of methanol-grown methylosinus trichosporium and occurred almost wholly in the soluble fraction of the cell. the enzyme, purified by deae-sephadex and sephadex g-100 chromatography, showed broad specificity toward different substrates and oxidized the aromatic alcohols benzyl, vanillyl, and veratryl alcohols in addition to a range of aliphatic primary alcohols. no enzyme activity was found toward the corresponding aldehyd ... | 1990 | 2193913 |
| formate dehydrogenase from the methane oxidizer methylosinus trichosporium ob3b. | formate dehydrogenase (nad+ dependent) was isolated from the obligate methanotroph methylosinus trichosporium ob3b. when the enzyme was isolated anaerobically, two forms of the enzyme were seen on native polyacrylamide gels, de-52 cellulose and sephacryl s-300 columns; they were approximately 315,000 and 155,000 daltons. the enzyme showed two subunits on sodium dodecyl sulfate-polyacrylamide gels. the mr of the alpha-subunit was 53,800 +/- 2,800, and that of the beta-subunit was 102,600 +/- 3,90 ... | 1990 | 2376564 |
| biodegradation of trichloroethylene by methylosinus trichosporium ob3b. | the methanotroph methylosinus trichosporium ob3b, a type ii methanotroph, degraded trichloroethylene at rates exceeding 1.2 mmol/h per g (dry weight) following the appearance of soluble methane monooxygenase in continuous and batch cultures. cells capable oxidizing trichloroethylene contained components of soluble methane monooxygenase as demonstrated by western blot (immunoblot) analysis with antibodies prepared against the purified enzyme. growth of cultures in a medium containing 0.25 microm ... | 1989 | 2515801 |
| degradation of chlorinated aliphatic hydrocarbons by methylosinus trichosporium ob3b expressing soluble methane monooxygenase. | degradation of trichloroethylene (tce) by the methanotrophic bacterium methylosinus trichosporium ob3b was studied by using cells grown in continuous culture. tce degradation was a strictly cometabolic process, requiring the presence of a cosubstrate, preferably formate, and oxygen. m. trichosporium ob3b cells degraded tce only when grown under copper limitation and when the soluble methane monooxygenase was derepressed. during tce degradation, nearly total dechlorination occurred, as indicated ... | 1989 | 2624462 |
| isolation, characterization, and biological activity of ferredoxin-nad+ reductase from the methane oxidizer methylosinus trichosporium ob3b. | a ferredoxin-nad+ oxidoreductase (ec 1.18.1.3) has been isolated from extracts of the obligate methanotroph methylosinus trichosporium ob3b. this enzyme was shown to couple electron flow from formate dehydrogenase (nad+ requiring) to ferredoxin. ferredoxin-nad+ reductase was purified to homogeneity by conventional chromatography techniques and was shown to be a flavoprotein with a molecular weight of 36,000 +/- 1,000. this ferredoxin reductase was specific for nadh (km, 125 microm) and coupled e ... | 1989 | 2768195 |
| regulation of two nickel-requiring (inducible and constitutive) hydrogenases and their coupling to nitrogenase in methylosinus trichosporium ob3b. | two uptake hydrogenases were found in the obligate methanotroph methylosinus trichosporium ob3b; one was constitutive, and a second was induced by h2. both hydrogenases could be assayed by measuring methylene blue reduction anaerobically or by coupling their activity to nitrogenase acetylene reduction activity in vivo in an o2-dependent reaction. the h2 concentration for half-maximal activity of the inducible and constitutive hydrogenases in both assays was 0.01 and 0.5 bar (1 and 50 kpa), respe ... | 1987 | 3115963 |
| degradation of trichloroethylene by toluene dioxygenase in whole-cell studies with pseudomonas putida f1. | toluene-induced cells of pseudomonas putida f1 removed trichloroethylene from growth media at a significantly greater initial rate than the methanotroph methylosinus trichosporium ob3b. with toluene-induced p. putida f1, the initial degradation rate varied linearly with trichloroethylene concentration over the range of 8 to 80 microm (1.05 to 10.5 ppm). at 80 microm (10.5 ppm) trichloroethylene and 30 degrees c, the initial rate was 1.8 nmol/min per mg of total cell protein, but the rate decreas ... | 1988 | 3415234 |
| structure of methylosinus trichosporium exospores. | methylosinus trichosporium exospores did not display a well-defined cortex or an exosporium. a thick, electron-dense exospore wall was characteristic of the exospores. located on the exterior of the exospore wall was a cell wall to which a well-defined capsule was attached. an extensive lamellar intracytoplasmic membrane system characteristic of the kind in vegetative cells of this bacterium was present along the interior periphery of the exospore wall. upon germination of m. trichosporium exosp ... | 1980 | 6767693 |
| bacteriophages of methanotrophic bacteria. | bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the soviet union. altogether, 23 phage strains were isolated: 10 strains that specifically lysed only methylosinus sporium strains, 2 strains that each lysed 1 of 5 methylosinus trichosporium strains studied, and 11 strains that lysed ... | 1980 | 6774962 |
| exospore formation in methylosinus trichosporium. | formation of exospores in methylosinus trichosporium was examined by electron microscopy; serial sectioning was used to visualize the shape and location of the developing exospore in relation to the vegetative cell. the initial stage was the formation of a budlike enlargement on one end of the vegetative cell. the enlargement was surrounded by the exospore capsule, and the cell wall was continuous around both the cell and the developing exospore. a constriction occurred in the area where the bud ... | 1982 | 7054146 |
| cometabolic degradation of trichloroethylene by pseudomonas cepacia g4 in a chemostat with toluene as the primary substrate. | pseudomonas cepacia g4 is capable of cometabolic degradation of trichloroethylene (tce) if the organism is grown on certain aromatic compounds. to obtain more insight into the kinetics of tce degradation and the effect of tce transformation products, we have investigated the simultaneous conversion of toluene and tce in steady-state continuous culture. the organism was grown in a chemostat with toluene as the carbon and energy source at a range of volumetric tce loading rates, up to 330 mumol/li ... | 1994 | 7524444 |
| detection of methanotrophic bacteria in environmental samples with the pcr. | we designed pcr primers by using the dna sequences of the soluble methane monooxygenase gene clusters of methylosinus trichosporium ob3b and methylococcus capsulatus (bath), and these primers were found to be specific for four of the five structural genes in the soluble methane monooxygenase gene clusters of several methanotrophs. we also designed primers for the gram-negative methylotroph-specific methanol dehydrogenase gene moxf. the specificity of these primers was confirmed by hybridizing an ... | 1995 | 7887594 |
| trichloroethylene and chloroform degradation by a recombinant pseudomonad expressing soluble methane monooxygenase from methylosinus trichosporium ob3b. | soluble methane monooxygenase (smmo) from methylosinus trichosporium ob3b can degrade many halogenated aliphatic compounds that are found in contaminated soil and groundwater. this enzyme oxidizes the most frequently detected pollutant, trichloroethylene (tce), at least 50 times faster than other enzymes. however, slow growth of the strain, strong competition between tce and methane for smmo, and repression of the smmo locus by low concentrations of copper ions limit the use of this bacterium. t ... | 1994 | 8074526 |
| phenotypic characterization of copper-resistant mutants of methylosinus trichosporium ob3b. | cultures of methylosinus trichosporium ob3b grown in the presence of very low concentrations of copper synthesize a soluble methane monooxygenase (smmo) that efficiently catalyzes the oxidation of trichloroethylene and other organic pollutants. recently, we isolated five m. trichosporium ob3b mutants that express smmo activity when grown in the presence of elevated copper concentrations (p.a. phelps, s. k. agarwal, g. e. speitel, jr., and g. georgiou, appl. environ. microbiol. 58:3701-3708, 1992 ... | 1993 | 8215352 |
| characterization of the methanotrophic bacterial community present in a trichloroethylene-contaminated subsurface groundwater site. | groundwater, contaminated with trichloroethylene (tce) and tetrachloroethylene (pce), was collected from 13 monitoring wells at area m on the u.s. department of energy savannah river site near aiken, s.c. filtered groundwater samples were enriched with methane, leading to the isolation of 25 methanotrophic isolates. the phospholipid fatty acid profiles of all the isolates were dominated by 18:1 omega 8c (60 to 80%), a signature lipid for group ii methanotrophs. subsequent phenotypic testing show ... | 1993 | 8368829 |
| biodegradation of individual and multiple chlorinated aliphatic hydrocarbons by methane-oxidizing cultures. | the microbial degradation of chlorinated and nonchlorinated methanes, ethanes, and ethanes by a mixed methane-oxidizing culture grown under chemostat and batch conditions is evaluated and compared with that by two pure methanotrophic strains: cac1 (isolated from the mixed culture) and methylosinus trichosporium ob3b. with the exception of 1,1-dichloroethylene, the transformation capacity (tc) for each chlorinated aliphatic hydrocarbon was generally found to be in inverse proportion to its chlori ... | 1996 | 8795228 |
| crystal structure of the hydroxylase component of methane monooxygenase from methylosinus trichosporium ob3b. | methane monooxygenase (mmo), found in aerobic methanotrophic bacteria, catalyzes the o2-dependent conversion of methane to methanol. the soluble form of the enzyme (smmo) consists of three components: a reductase, a regulatory "b" component (mmob), and a hydroxylase component (mmoh), which contains a hydroxo-bridged dinuclear iron cluster. two genera of methanotrophs, termed type x and type ii, which differ markedly in cellular and metabolic characteristics, are known to produce the smmo. the st ... | 1997 | 9070438 |
| the soluble methane monooxygenase gene cluster of the trichloroethylene-degrading methanotroph methylocystis sp. strain m. | in methanotrophic bacteria, methane is oxidized to methanol by the enzyme methane monooxygenase (mmo). the soluble mmo enzyme complex from methylocystis sp. strain m also oxidizes a wide range of aliphatic and aromatic compounds, including trichloroethylene. in this study, heterologous dna probes from the type ii methanotroph methylosinus trichosporium ob3b were used to isolate souble mmo (smmo) genes from the type ii methanotroph methylocystis sp. strain m. smmo genes from strain m are clustere ... | 1997 | 9143121 |
| effect of selected monoterpenes on methane oxidation, denitrification, and aerobic metabolism by bacteria in pure culture. | selected monoterpenes inhibited methane oxidation by methanotrophs (methylosinus trichosporium ob3b, methylobacter luteus), denitrification by environmental isolates, and aerobic metabolism by several heterotrophic pure cultures. inhibition occurred to various extents and was transient. complete inhibition of methane oxidation by methylosinus trichosporium ob3b with 1.1 mm (-)-alpha-pinene lasted for more than 2 days with a culture of optical density of 0.05 before activity resumed. inhibition w ... | 1998 | 9464387 |
| acidophilic methanotrophic communities from sphagnum peat bogs. | highly enriched methanotrophic communities (> 25 serial transfers) were obtained from acidic ombrotrophic peat bogs from four boreal forest sites. the enrichment strategy involved using media conditions that were associated with the highest rates of methane uptake by the original peat samples, namely, the use of diluted mineral medium of low buffering capacity, moderate incubation temperature (20 degrees c), and ph values of 3 to 6. enriched communities contained a mixture of rod-shaped bacteria ... | 1998 | 9501432 |
| isolation of copper biochelates from methylosinus trichosporium ob3b and soluble methane monooxygenase mutants. | methylosinus trichosporium ob3b produces an extracellular copper-binding ligand (cbl) with high affinity for copper. wild-type cells and mutants that express soluble methane monooxygenase (smmo) in the presence and absence of copper (smmoc) were used to obtain cell exudates that were separated and analyzed by size exclusion high-performance liquid chromatography. a single chromatographic peak, when present, contained most of the aqueous-phase cu(ii) present in the culture medium. in mutant cultu ... | 1998 | 9501450 |
| effects of bacterial host and dichloromethane dehalogenase on the competitiveness of methylotrophic bacteria growing with dichloromethane. | methylobacterium sp. strain dm4 and methylophilus sp. strain dm11 can grow with dichloromethane (dcm) as the sole source of carbon and energy by virtue of homologous glutathione-dependent dcm dehalogenases with markedly different kinetic properties (the kcat values of the enzymes of these strains are 0.6 and 3.3 s-1, respectively, and the km values are 9 and 59 microm, respectively). these strains, as well as transconjugant bacteria expressing the dcm dehalogenase gene (dcma) from dm11 or dm4 on ... | 1998 | 9546153 |
| a novel phosphorylation-dependent rnase activity of gap-sh3 binding protein: a potential link between signal transduction and rna stability. | a potential p120 gtpase-activating protein (rasgap) effector, g3bp (rasgap src homology 3 [sh3] binding protein), was previously identified based on its ability to bind the sh3 domain of rasgap. here we show that g3bp colocalizes and physically interacts with rasgap at the plasma membrane of serum-stimulated but not quiescent chinese hamster lung fibroblasts. in quiescent cells, g3bp was hyperphosphorylated on serine residues, and this modification was essential for its activity. indeed, g3bp ha ... | 1998 | 9632780 |
| construction and use of an ipb dna module to generate pseudomonas strains with constitutive trichloroethene and isopropylbenzene oxidation activity. | pseudomonas sp. strain jr1 exhibits trichloroethene (tce) oxidation activity with isopropylbenzene (ipb) as the inducer substrate. we previously reported the genes encoding the first three enzymes of the ipb-degradative pathway (ipba1, ipba2, ipba3, ipba4, ipbb, and ipbc) and identified the initial ipb dioxygenase (ipba1 a2a3a4) as responsible for tce cooxidation (u. pflugmacher, b. averhoff, and g. gottschalk, appl. environ. microbiol. 62:3967-3977, 1996). primer extension analyses revealed mul ... | 1998 | 9647815 |
| copper-binding compounds from methylosinus trichosporium ob3b. | two copper-binding compounds/cofactors (cbcs) were isolated from the spent media of both the wild type and a constitutive soluble methane monooxygenase (smmoc) mutant, pp319 (p. a. phelps et al., appl. environ. microbiol. 58:3701-3708, 1992), of methylosinus trichosporium ob3b. both cbcs are small polypeptides with molecular masses of 1,218 and 779 da for cbc-l1 and cbc-l2, respectively. the amino acid sequence of cbc-l1 is s?mypgs?m, and that of cbc-l2 is spmp?s. copper-free cbcs showed absorpt ... | 1998 | 9658004 |
| a glutathione s-transferase with activity towards cis-1, 2-dichloroepoxyethane is involved in isoprene utilization by rhodococcus sp. strain ad45. | rhodococcus sp. strain ad45 was isolated from an enrichment culture on isoprene (2-methyl-1,3-butadiene). isoprene-grown cells of strain ad45 oxidized isoprene to 3,4-epoxy-3-methyl-1-butene, cis-1, 2-dichloroethene to cis-1,2-dichloroepoxyethane, and trans-1, 2-dichloroethene to trans-1,2-dichloroepoxyethane. isoprene-grown cells also degraded cis-1,2-dichloroepoxyethane and trans-1, 2-dichloroepoxyethane. all organic chlorine was liberated as chloride during degradation of cis-1,2-dichloroepox ... | 1998 | 9687433 |
| oxidation of trichloroethylene, 1,1-dichloroethylene, and chloroform by toluene/o-xylene monooxygenase from pseudomonas stutzeri ox1. | toluene/o-xylene monooxygenase (tomo) from pseudomonas stutzeri ox1, which oxidizes toluene and o-xylene, was examined for its ability to degrade the environmental pollutants trichloroethylene (tce), 1, 1-dichloroethylene (1,1-dce), cis-1,2-dce, trans-1,2-dce, chloroform, dichloromethane, phenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, and 2,3,4,5, 6-pentachlorophenol. escherichia coli jm109 that expressed tomo from genes on plasmid pbz1260 un ... | 1998 | 9687467 |
| effect of nitrogen source on growth and trichloroethylene degradation by methane-oxidizing bacteria. | the effect of nitrogen source on methane-oxidizing bacteria with respect to cellular growth and trichloroethylene (tce) degradation ability were examined. one mixed chemostat culture and two pure type ii methane-oxidizing strains, methylosinus trichosporium ob3b and strain cac-2, which was isolated from the chemostat culture, were used in this study. all cultures were able to grow with each of three different nitrogen sources: ammonia, nitrate, and molecular nitrogen. both m. trichosporium ob3b ... | 1998 | 9726896 |
| analysis of the gene cluster encoding toluene/o-xylene monooxygenase from pseudomonas stutzeri ox1. | the toluene/o-xylene monooxygenase cloned from pseudomonas stutzeri ox1 displays a very broad range of substrates and a very peculiar regioselectivity, because it is able to hydroxylate more than one position on the aromatic ring of several hydrocarbons and phenols. the nucleotide sequence of the gene cluster coding for this enzymatic system has been determined. the sequence analysis revealed the presence of six open reading frames (orfs) homologous to other genes clustered in operons coding for ... | 1998 | 9758777 |
| distribution and life strategies of two bacterial populations in a eutrophic lake | monoclonal antibodies and epifluorescence microscopy were used to determine the depth distribution of two indigenous bacterial populations in the stratified lake plusssee and characterize their life strategies. populations of comamonas acidovorans px54 showed a depth distribution with maximum abundances in the oxic epilimnion, whereas aeromonas hydrophila pu7718 showed a depth distribution with maximum abundances in the anoxic thermocline layer (metalimnion), i. e., in the water layer with the h ... | 1998 | 9758799 |
| identification of chlorobenzene dioxygenase sequence elements involved in dechlorination of 1,2,4,5-tetrachlorobenzene. | the teca chlorobenzene dioxygenase and the todcba toluene dioxygenase exhibit substantial sequence similarity yet have different substrate specificities. escherichia coli cells producing recombinant teca enzyme dioxygenate and simultaneously eliminate a halogen substituent from 1,2,4,5-tetrachlorobenzene but show no activity toward benzene, whereas those producing todcba dioxygenate benzene but not tetrachlorobenzene. a hybrid teca dioxygenase variant containing the large alpha-subunit of the to ... | 1998 | 9791099 |
| low-concentration kinetics of atmospheric ch4 oxidation in soil and mechanism of nh4+ inhibition | nh4+ inhibition kinetics for ch4 oxidation were examined at near-atmospheric ch4 concentrations in three upland forest soils. whether nh4+-independent salt effects could be neutralized by adding nonammoniacal salts to control samples in lieu of deionized water was also investigated. because the levels of exchangeable endogenous nh4+ were very low in the three soils, desorption of endogenous nh4+ was not a significant factor in this study. the km(app) values for water-treated controls were 9.8, 2 ... | 1998 | 9797279 |
| whole-cell kinetics of trichloroethylene degradation by phenol hydroxylase in a ralstonia eutropha jmp134 derivative | the rate, progress, and limits of trichloroethylene (tce) degradation by ralstonia eutropha aek301/pyk3021 whole cells were examined in the absence of aromatic induction. at tce concentrations up to 800 &mgr;m, degradation rates were sustained until tce was no longer detectable. the ks and vmax for tce degradation by aek301/pyk3021 whole cells were determined to be 630 &mgr;m and 22.6 nmol/min/mg of total protein, respectively. the sustained linear rates of tce degradation by aek301/pyk3021 up t ... | 1998 | 9797289 |
| molecular detection, isolation, and physiological characterization of functionally dominant phenol-degrading bacteria in activated sludge. | dna was isolated from phenol-digesting activated sludge, and partial fragments of the 16s ribosomal dna (rdna) and the gene encoding the largest subunit of multicomponent phenol hydroxylase (lmph) were amplified by pcr. an analysis of the amplified fragments by temperature gradient gel electrophoresis (tgge) demonstrated that two major 16s rdna bands (bands r2 and r3) and two major lmph gene bands (bands p2 and p3) appeared after the activated sludge became acclimated to phenol. the nucleotide s ... | 1998 | 9797297 |
| methanotrophs and methanogens in masonry | methanotrophs were present in 48 of 225 stone samples which were removed from 19 historical buildings in germany and italy. the average cell number of methanotrophs was 20 cfu per g of stone, and their activities ranged between 11 and 42 pmol of ch4 g of stone-1 day-1. twelve strains of methane-oxidizing bacteria were isolated. they belonged to the type ii methanotrophs of the genera methylocystis, methylosinus, and methylobacterium. in masonry, growth substrates like methane or methanol are ava ... | 1998 | 9797318 |
| assessment of changes in microbial community structure during operation of an ammonia biofilter with molecular tools. | biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. in this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. both 16s rrna and ammonia monooxygenase (amoa) genes were used to characterize the heterotrophi ... | 1998 | 9835577 |
| induction of the tod operon by trichloroethylene in pseudomonas putida tva8. | bioluminescence, mrna levels, and toluene degradation rates in pseudomonas putida tva8 were measured as a function of various concentrations of toluene and trichloroethylene (tce). tva8 showed an increasing bioluminescence response to increasing tce and toluene concentrations. compared to uninduced tva8 cultures, todc1 mrna levels increased 11-fold for tce-treated cultures and 13-fold for toluene-treated cultures. compared to uninduced p. putida f1 cultures, todc1 mrna levels increased 4.4-fold ... | 1998 | 9835608 |
| cytochrome p460 genes from the methanotroph methylococcus capsulatus bath. | p460 cytochromes catalyze the oxidation of hydroxylamine to nitrite. they have been isolated from the ammonia-oxidizing bacterium nitrosomonas europaea (r. h. erickson and a. b. hooper, biochim. biophys. acta 275:231-244, 1972) and the methane-oxidizing bacterium methylococcus capsulatus bath (j. a. zahn et al., j. bacteriol. 176:5879-5887, 1994). a degenerate oligonucleotide probe was synthesized based on the n-terminal amino acid sequence of cytochrome p460 and used to identify a dna fragment ... | 1998 | 9851984 |
| high-molecular-mass multi-c-heme cytochromes from methylococcus capsulatus bath. | the polypeptide and structural gene for a high-molecular-mass c-type cytochrome, cytochrome c553o, was isolated from the methanotroph methylococcus capsulatus bath. cytochrome c553o is a homodimer with a subunit molecular mass of 124,350 da and an isoelectric point of 6. 0. the heme c concentration was estimated to be 8.2 +/- 0.4 mol of heme c per subunit. the electron paramagnetic resonance spectrum showed the presence of multiple low spin, s = 1/2, hemes. a degenerate oligonucleotide probe syn ... | 1999 | 9922265 |
| monitoring methanotrophic bacteria in hybrid anaerobic-aerobic reactors with pcr and a catabolic gene probe. | we attempted to mimic in small upflow anaerobic sludge bed (uasb) bioreactors the metabolic association found in nature between methanogens and methanotrophs. uasb bioreactors were inoculated with pure cultures of methanotrophs, and the bioreactors were operated by using continuous low-level oxygenation in order to favor growth and/or survival of methanotrophs. unlike the reactors in other similar studies, the hybrid anaerobic-aerobic bioreactors which we used were operated synchronously, not se ... | 1999 | 9925557 |
| influence of light intensity on methanotrophic bacterial activity in petit saut reservoir, french guiana. | one year after impoundment in january 1994, methanotrophic bacteria in petit saut reservoir (french guiana) were active at the oxic-anoxic interface. this activity was revealed by the sudden extinction of diffusive methane emission (600 metric tons of ch4. day-1 for the whole lake surface area, i.e., 360 km2). lifting of inhibition was suspected. after reviewing the potential inhibitors of this physiological guild (o2, nh4+, sulfides) and considering the similarities with nitrifiers, we suggest ... | 1999 | 9925579 |
| inactivation of toluene 2-monooxygenase in burkholderia cepacia g4 by alkynes. | high concentrations of acetylene (10 to 50% [vol/vol] gas phase) were required to inhibit the growth of burkholderia cepacia g4 on toluene, while 1% (vol/vol) (gas phase) propyne or 1-butyne completely inhibited growth. low concentrations of longer-chain alkynes (c5 to c10) were also effective inhibitors of toluene-dependent growth, and 2- and 3-alkynes were more potent inhibitors than their 1-alkyne counterparts. exposure of toluene-grown b. cepacia g4 to alkynes resulted in the irreversible lo ... | 1999 | 9925593 |
| high-affinity methane oxidation by a soil enrichment culture containing a type ii methanotroph. | methanotrophic bacteria in an organic soil were enriched on gaseous mixing ratios of <275 parts per million of volume (ppmv) of methane (ch4). after 4 years of growth and periodic dilution (>10(20) times the initial soil inoculum), a mixed culture was obtained which displayed an apparent half-saturation constant [km(app)] for ch4 of 56 to 186 nm (40 to 132 ppmv). this value was the same as that measured in the soil itself and about 1 order of magnitude lower than reported values for pure culture ... | 1999 | 10049856 |
| purification of a glutathione s-transferase and a glutathione conjugate-specific dehydrogenase involved in isoprene metabolism in rhodococcus sp. strain ad45. | a glutathione s-transferase (gst) with activity toward 1, 2-epoxy-2-methyl-3-butene (isoprene monoxide) and cis-1, 2-dichloroepoxyethane was purified from the isoprene-utilizing bacterium rhodococcus sp. strain ad45. the homodimeric enzyme (two subunits of 27 kda each) catalyzed the glutathione (gsh)-dependent ring opening of various epoxides. at 5 mm gsh, the enzyme followed michaelis-menten kinetics for isoprene monoxide and cis-1, 2-dichloroepoxyethane, with vmax values of 66 and 2.4 micromol ... | 1999 | 10094686 |
| molecular analysis of a novel methanesulfonic acid monooxygenase from the methylotroph methylosulfonomonas methylovora. | methylosulfonomonas methylovora m2 is an unusual gram-negative methylotrophic bacterium that can grow on methanesulfonic acid (msa) as the sole source of carbon and energy. oxidation of msa by this bacterium is carried out by a multicomponent msa monooxygenase (msamo). cloning and sequencing of a 7.5-kbp sphi fragment of chromosomal dna revealed four tightly linked genes encoding this novel monooxygenase. analysis of the deduced msamo polypeptide sequences indicated that the enzyme contains a tw ... | 1999 | 10094704 |
| the alkene monooxygenase from xanthobacter strain py2 is closely related to aromatic monooxygenases and catalyzes aromatic monohydroxylation of benzene, toluene, and phenol. | the genes encoding the six polypeptide components of the alkene monooxygenase from xanthobacter strain py2 (xamo) have been located on a 4.9-kb fragment of chromosomal dna previously cloned in cosmid pny2. sequencing and analysis of the predicted amino acid sequences indicate that the components of xamo are homologous to those of the aromatic monooxygenases, toluene 2-, 3-, and 4-monooxygenase and benzene monooxygenase, and that the gene order is identical. the genes and predicted polypeptides a ... | 1999 | 10103255 |
| molecular analyses of the methane-oxidizing microbial community in rice field soil by targeting the genes of the 16s rrna, particulate methane monooxygenase, and methanol dehydrogenase | rice field soil with a nonsaturated water content induced ch4 consumption activity when it was supplemented with 5% ch4. after a lag phase of 3 days, ch4 was consumed rapidly until the concentration was less than 1.8 parts per million by volume (ppmv). however, the soil was not able to maintain the oxidation activity at near-atmospheric ch4 mixing ratios (i.e., 5 ppmv). the soil microbial community was monitored by performing denaturing gradient gel electrophoresis (dgge) during the oxidation pr ... | 1999 | 10223989 |
| structure of the soluble methane monooxygenase regulatory protein b. | the soluble methane monooxygenase (smmo; ec 1.14.13.25) from the pseudothermophile methylococcus capsulatus (bath) is a three-component enzyme system that catalyzes the selective oxidation of methane to methanol. we have used nmr spectroscopy to produce a highly refined structure of mmob, the 16-kda regulatory protein of this system. this structure has a unique and intricate fold containing seven beta-strands forming two beta-sheets oriented perpendicular to each other and bridged by three alpha ... | 1999 | 10393915 |
| purification and characterization of the soluble methane monooxygenase of the type ii methanotrophic bacterium methylocystis sp. strain wi 14. | methane monooxygenase (mmo) catalyzes the oxidation of methane to methanol as the first step of methane degradation. a soluble nad(p)h-dependent methane monooxygenase (smmo) from the type ii methanotrophic bacterium wi 14 was purified to homogeneity. sequencing of the 16s rdna and comparison with that of other known methanotrophic bacteria confirmed that strain wi 14 is very close to the genus methylocystis. the smmo is expressed only during growth under copper limitation (<0.1 microm) and with ... | 1999 | 10473397 |
| distribution of tetrahydromethanopterin-dependent enzymes in methylotrophic bacteria and phylogeny of methenyl tetrahydromethanopterin cyclohydrolases. | the methylotrophic proteobacterium methylobacterium extorquens am1 possesses tetrahydromethanopterin (h(4)mpt)-dependent enzymes, which are otherwise specific to methanogenic and sulfate-reducing archaea and which have been suggested to be involved in formaldehyde oxidation to co(2) in m. extorquens am1. the distribution of h(4)mpt-dependent enzyme activities in cell extracts of methylotrophic bacteria from 13 different genera are reported. h(4)mpt-dependent activities were detected in all of th ... | 1999 | 10482517 |
| utilization of trihalogenated propanes by agrobacterium radiobacter ad1 through heterologous expression of the haloalkane dehalogenase from rhodococcus sp. strain m15-3. | trihalogenated propanes are toxic and recalcitrant organic compounds. attempts to obtain pure bacterial cultures able to use these compounds as sole carbon and energy sources were unsuccessful. both the haloalkane dehalogenase from xanthobacter autotrophicus gj10 (dhla) and that from rhodococcus sp. strain m15-3 (dhaa) were found to dehalogenate trihalopropanes to 2,3-dihalogenated propanols, but the kinetic properties of the latter enzyme are much better. broad-host-range dehalogenase expressio ... | 1999 | 10508091 |
| diversity in butane monooxygenases among butane-grown bacteria. | butane monooxygenases of butane-grown pseudomonas butanovora, mycobacterium vaccae job5, and an environmental isolate, cf8, were compared at the physiological level. the presence of butane monooxygenases in these bacteria was indicated by the following results. (i) o(2) was required for butane degradation. (ii) 1-butanol was produced during butane degradation. (iii) acetylene inhibited both butane oxidation and 1-butanol production. the responses to the known monooxygenase inactivator, ethylene, ... | 1999 | 10508093 |
| aerobic degradation of 1,1,1-trichloroethane by mycobacterium spp. isolated from soil. | two strains of 1,1,1-trichloroethane (tca)-degrading bacteria, ta5 and ta27, were isolated from soil and identified as mycobacterium spp. strains ta5 and ta27 could degrade 25 and 75 mg. liter of tca(-1) cometabolically in the presence of ethane as a carbon source, respectively. the compound 2,2,2-trichloroethanol was produced as a metabolite of the degradation process. | 1999 | 10508110 |
| methanotroph diversity in landfill soil: isolation of novel type i and type ii methanotrophs whose presence was suggested by culture-independent 16s ribosomal dna analysis. | the diversity of the methanotrophic community in mildly acidic landfill cover soil was assessed by three methods: two culture-independent molecular approaches and a traditional culture-based approach. for the first of the molecular studies, two primer pairs specific for the 16s rrna gene of validly published type i (including the former type x) and type ii methanotrophs were identified and tested. these primers were used to amplify directly extracted soil dna, and the products were used to const ... | 1999 | 10543800 |
| molecular characterization of functional and phylogenetic genes from natural populations of methanotrophs in lake sediments. | the 16s rrna and pmoa genes from natural populations of methane-oxidizing bacteria (methanotrophs) were pcr amplified from total community dna extracted from lake washington sediments obtained from the area where peak methane oxidation occurred. clone libraries were constructed for each of the genes, and approximately 200 clones from each library were analyzed by using restriction fragment length polymorphism (rflp) and the tetrameric restriction enzymes mspi, haeiii, and hhai. the pcr products ... | 1999 | 10543824 |
| soluble methane monooxygenase gene clusters from trichloroethylene-degrading methylomonas sp. strains and detection of methanotrophs during in situ bioremediation. | the soluble mmo (smmo) gene clusters from group i methanotrophs were characterized. an 8.1-kb kpni fragment from methylomonas sp. strain kswiii and a 7.5-kb sali fragment from methylomonas sp. strain kspiii which contained the smmo gene clusters were cloned and sequenced. the sequences of these two fragments were almost identical. the smmo gene clusters in the fragment consisted of six open reading frames which were 52 to 79% similar to the corresponding genes of previously described smmo gene c ... | 1999 | 10583965 |
| molecular analysis of the pmo (particulate methane monooxygenase) operons from two type ii methanotrophs. | the particulate methane monooxygenase gene clusters, pmocab, from two representative type ii methanotrophs of the alpha-proteobacteria, methylosinus trichosporium ob3b and methylocystis sp. strain m, have been cloned and sequenced. primer extension experiments revealed that the pmo cluster is probably transcribed from a single transcriptional start site located 300 bp upstream of the start of the first gene, pmoc, for methylocystis sp. strain m. immediately upstream of the putative start site, c ... | 2000 | 10698759 |
| characterization of the gene cluster involved in isoprene metabolism in rhodococcus sp. strain ad45. | the genes involved in isoprene (2-methyl-1,3-butadiene) utilization in rhodococcus sp. strain ad45 were cloned and characterized. sequence analysis of an 8.5-kb dna fragment showed the presence of 10 genes of which 2 encoded enzymes which were previously found to be involved in isoprene degradation: a glutathione s-transferase with activity towards 1,2-epoxy-2-methyl-3-butene (isoi) and a 1-hydroxy-2-glutathionyl-2-methyl-3-butene dehydrogenase (isoh). furthermore, a gene encoding a second gluta ... | 2000 | 10715003 |
| effect of copper speciation on whole-cell soluble methane monooxygenase activity in methylosinus trichosporium ob3b. | soluble methane monooxygenase (smmo) activity in methylosinus trichosporium ob3b was found to be more strongly affected as copper-to-biomass ratios changed in a newly developed medium, m2m, which uses pyrophosphate for metal chelation, than in nitrate mineral salts (nms), which uses edta. when m2m medium was amended with edta, smmo activity was similar to that in nms medium, indicating that edta-bound copper had lower bioavailability than pyrophosphate-bound copper. edta did not limit the associ ... | 2000 | 10742271 |
| molecular analyses of novel methanotrophic communities in forest soil that oxidize atmospheric methane. | forest and other upland soils are important sinks for atmospheric ch(4), consuming 20 to 60 tg of ch(4) per year. consumption of atmospheric ch(4) by soil is a microbiological process. however, little is known about the methanotrophic bacterial community in forest soils. we measured vertical profiles of atmospheric ch(4) oxidation rates in a german forest soil and characterized the methanotrophic populations by pcr and denaturing gradient gel electrophoresis (dgge) with primer sets targeting the ... | 2000 | 10788342 |
| toluene monooxygenase-catalyzed epoxidation of alkenes. | several toluene monooxygenase-producing organisms were tested for their ability to oxidize linear alkenes and chloroalkenes three to eight carbons long. each of the wild-type organisms degraded all of the alkenes that were tested. epoxides were produced during the oxidation of butene, butadiene, and pentene but not hexene or octadiene. a strain of escherichia coli expressing the cloned toluene-4-monooxygenase (t4mo) of pseudomonas mendocina kr1 was able to oxidize butene, butadiene, pentene, and ... | 2000 | 10788354 |
| new insights into methyl bromide cooxidation by nitrosomonas europaea obtained by experimenting with moderately low density cell suspensions. | we examined the rates and sustainability of methyl bromide (mebr) oxidation in moderately low density cell suspensions ( approximately 6 x 10(7) cells ml(-1)) of the nh(3)-oxidizing bacterium nitrosomonas europaea. in the presence of 10 mm nh(4)(+) and 0.44, 0. 22, and 0.11 mm mebr, the initial rates of mebr oxidation were sustained for 12, 12, and 24 h, respectively, despite the fact that only 10% of the nh(4)(+), 18% of the nh(4)(+), and 35% of the nh(4)(+), respectively, were consumed. althou ... | 2000 | 10877761 |
| characterization of an isolate that uses vinyl chloride as a growth substrate under aerobic conditions. | an aerobic enrichment culture was developed by using vinyl chloride (vc) as the sole organic carbon and electron donor source. vc concentrations as high as 7.3 mm were biodegraded without apparent inhibition. vc use did not occur when nitrate was provided as the electron acceptor. a gram-negative, rod-shaped, motile isolate was obtained from the enrichment culture and identified based on biochemical characteristics and the sequence of its 16s rrna gene as pseudomonas aeruginosa, designated strai ... | 2000 | 10919818 |
| production and consumption of nitric oxide by three methanotrophic bacteria. | we studied nitrogen oxide production and consumption by methanotrophs methylobacter luteus (group i), methylosinus trichosporium ob3b (group ii), and an isolate from a hardwood swamp soil, here identified by 16s ribosomal dna sequencing as methylobacter sp. strain t20 (group i). all could consume nitric oxide (nitrogen monoxide, no), and produce small amounts of nitrous oxide (n(2)o). only methylobacter strain t20 produced large amounts of no (>250 parts per million by volume [ppmv] in the heads ... | 2000 | 10966405 |
| starvation improves survival of bacteria introduced into activated sludge. | a phenol-degrading bacterium, ralstonia eutropha e2, was grown in luria-bertani (lb) medium or in an inorganic medium (called mp) supplemented with phenol and harvested at the late-exponential-growth phase. phenol-acclimated activated sludge was inoculated with the e2 cells immediately after harvest or after starvation in mp for 2 or 7 days. the densities of the e2 populations in the activated sludge were then monitored by quantitative pcr. the e2 cells grown on phenol and starved for 2 days (p- ... | 2000 | 10966407 |
| hydrogen peroxide sensitivity of catechol-2,3-dioxygenase: a cautionary note on use of xyle reporter fusions under aerobic conditions. | catechol-2,3-dioxygenase (c23o) of pseudomonas putida, encoded by the xyle gene, was found to be sensitive to hydrogen peroxide (h(2)o(2)) when used as a reporter in gene fusion constructs. exposure of pseudomonas aeruginosa kata or kata katb mutants harboring kata- or katb-lacz (encoding beta-galactosidase) or -xyle fusion plasmids to h(2)o(2) stimulated beta-galactosidase activity, while there was little or no detectable c23o activity in these strains. more than 95% of c23o activity was lost a ... | 2000 | 10966438 |
| starvation alters the apparent half-saturation constant for methane in the type ii methanotroph methylocystis strain lr1. | when cells of a type ii methanotrophic bacterium (methylocystis strain lr1) were starved of methane, both the k(m(app)) and the v(max(app)) for methane decreased. the specific affinity (a(o)(s)) remained nearly constant. therefore, the decreased k(m(app)) in starved cells was probably not an adjustment to better utilize low-methane concentrations. | 2000 | 10966442 |
| trichloroethene reductive dehalogenase from dehalococcoides ethenogenes: sequence of tcea and substrate range characterization. | the anaerobic bacterium dehalococcoides ethenogenes is the only known organism that can completely dechlorinate tetrachloroethene or trichloroethene (tce) to ethene via dehalorespiration. one of two corrinoid-containing enzymes responsible for this pathway, tce reductive dehalogenase (tce-rdase) catalyzes the dechlorination of tce to ethene. tce-rdase dehalogenated 1,2-dichloroethane and 1, 2-dibromoethane to ethene at rates of 7.5 and 30 micromol/min/mg, respectively, similar to the rates for t ... | 2000 | 11097881 |
| molecular characterization of methanotrophic isolates from freshwater lake sediment. | profiles of dissolved o(2) and methane with increasing depth were generated for lake washington sediment, which suggested the zone of methane oxidation is limited to the top 0.8 cm of the sediment. methane oxidation potentials were measured for 0.5-cm layers down to 1.5 cm and found to be relatively constant at 270 to 350 micromol/liter of sediment/h. approximately 65% of the methane was oxidized to cell material or metabolites, a signature suggestive of type i methanotrophs. eleven methanotroph ... | 2000 | 11097900 |
| polyclonal antibodies recognizing the amob protein of ammonia oxidizers of the beta-subclass of the class proteobacteria. | a 41-kda protein of nitrosomonas eutropha was purified, and the n-terminal amino acid sequence was found to be nearly identical with the sequence of amob, a subunit of ammonia monooxygenase. this protein was used to develop polyclonal antibodies, which were highly specific for the detection of the four genera of ammonia oxidizers of the beta-subclass of proteobacteria (nitrosomonas, including nitrosococcus mobilis, which belongs phylogenetically to nitrosomonas; nitrosospira; nitrosolobus; and n ... | 2001 | 11133435 |
| chloromethane utilization gene cluster from hyphomicrobium chloromethanicum strain cm2(t) and development of functional gene probes to detect halomethane-degrading bacteria. | hyphomicrobium chloromethanicum cm2(t), an aerobic methylotrophic member of the alpha subclass of the class proteobacteria, can grow with chloromethane as the sole carbon and energy source. h. chloromethanicum possesses an inducible enzyme system for utilization of chloromethane, in which two polypeptides (67-kda cmua and 35-kda cmub) are expressed. previously, four genes, cmua, cmub, cmuc, and puru, were shown to be essential for growth of methylobacterium chloromethanicum on chloromethane. the ... | 2001 | 11133460 |
| influence of tomato genotype on growth of inoculated and indigenous bacteria in the spermosphere. | we previously demonstrated a genetic basis in tomato for support of the growth of a biological control agent, bacillus cereus uw85, in the spermosphere after seed inoculation (k. p. smith, j. handelsman, and r. m. goodman, proc. natl. acad. sci. usa 96:4786-4790, 1999). here we report results of studies examining the host effect on the support of growth of bacillus and pseudomonas strains, both inoculated on seeds and recruited from soil, using selected inbred tomato lines from the recombinant i ... | 2001 | 11157211 |
| expression of individual copies of methylococcus capsulatus bath particulate methane monooxygenase genes. | the expression of the two gene clusters encoding the particulate methane monooxygenase (pmmo) in methylococcus capsulatus bath was assessed by analysis of transcripts and by use of chromosomal gene fusions. the results suggest that the two clusters are functionally redundant but that relative expression alters depending on the copper levels available for growth. | 2001 | 11160118 |
| transcript analysis of multiple copies of amo (encoding ammonia monooxygenase) and hao (encoding hydroxylamine oxidoreductase) in nitrosomonas europaea. | the genes encoding ammonia monooxygenase (amocab), hydroxylamine oxidoreductase (hao), and the c-type cytochrome c-554 (hcy) are present in multiple copies in the genome of nitrosomonas europaea. the upstream regions of the two copies of amoc, the three copies of hao, and one copy of hcy were cloned and sequenced. primer extension reactions were done to identify transcription start sites for these genes, as well as for amoa. putative sigma(70) promoter sequences were found associated with all bu ... | 2001 | 11208810 |
| cytotoxicity associated with trichloroethylene oxidation in burkholderia cepacia g4. | the effects of trichloroethylene (tce) oxidation on toluene 2-monooxygenase activity, general respiratory activity, and cell culturability were examined in the toluene-oxidizing bacterium burkholderia cepacia g4. nonspecific damage outpaced inactivation of toluene 2-monooxygenase in b. cepacia g4 cells. cells that had degraded approximately 0.5 micromol of tce (mg of cells(-1)) lost 95% of their acetate-dependent o(2) uptake activity (a measure of general respiratory activity), yet toluene-depen ... | 2001 | 11319088 |
| kinetics of methyl t-butyl ether cometabolism at low concentrations by pure cultures of butane-degrading bacteria. | butane-oxidizing arthrobacter (atcc 27778) bacteria were shown to degrade low concentrations of methyl t-butyl ether (mtbe; range, 100 to 800 microg/liter) with an apparent half-saturation concentration (k(s)) of 2.14 mg/liter and a maximum substrate utilization rate (k(c)) of 0.43 mg/mg of total suspended solids per day. arthrobacter bacteria demonstrated mtbe degradation activity when grown on butane but not when grown on glucose, butanol, or tryptose phosphate broth. the presence of butane, t ... | 2001 | 11319100 |
| changes in activity and community structure of methane-oxidizing bacteria over the growth period of rice. | the activity and community structure of methanotrophs in compartmented microcosms were investigated over the growth period of rice plants. in situ methane oxidation was important only during the vegetative growth phase of the plants and later became negligible. the in situ activity was not directly correlated with methanotrophic cell counts, which increased even after the decrease in in situ activity, possibly due to the presence of both vegetative cells and resting stages. by dividing the micro ... | 2001 | 11375143 |
| bacteria mediate methylation of iodine in marine and terrestrial environments. | methyl iodide (ch(3)i) plays an important role in the natural iodine cycle and participates in atmospheric ozone destruction. however, the main source of this compound in nature is still unclear. here we report that a wide variety of bacteria including terrestrial and marine bacteria are capable of methylating the environmental level of iodide (0.1 microm). of the strains tested, rhizobium sp. strain mrcd 19 was chosen for further analysis, and it was found that the cell extract catalyzed the me ... | 2001 | 11375186 |
| effects of iron limitation on the degradation of toluene by pseudomonas strains carrying the tol (pwwo) plasmid. | most aerobic biodegradation pathways for hydrocarbons involve iron-containing oxygenases. in iron-limited environments, such as the rhizosphere, this may influence the rate of degradation of hydrocarbon pollutants. we investigated the effects of iron limitation on the degradation of toluene by pseudomonas putida mt2 and the transconjugant rhizosphere bacterium p. putida wcs358(pwwo), both of which contain the pwwo (tol) plasmid that harbors the genes for toluene degradation. the results of conti ... | 2001 | 11472911 |
| nifh sequences and nitrogen fixation in type i and type ii methanotrophs. | some methane-oxidizing bacteria (methanotrophs) are known to be capable of expressing nitrogenase and utilizing n2 as a nitrogen source. however, no sequences are available for nif genes in these strains, and the known nitrogen-fixing methanotrophs are confined mainly to a few genera. the purpose of this work was to assess the nitrogen-fixing capabilities of a variety of methanotroph strains. nifh gene fragments from four type i methanotrophs and seven type ii methanotrophs were pcr amplified an ... | 2001 | 11525998 |
| detection of methanotroph diversity on roots of submerged rice plants by molecular retrieval of pmoa, mmox, mxaf, and 16s rrna and ribosomal dna, including pmoa-based terminal restriction fragment length polymorphism profiling. | the diversity of methanotrophic bacteria associated with roots of submerged rice plants was assessed using cultivation-independent techniques. the research focused mainly on the retrieval of pmoa, which encodes the alpha subunit of the particulate methane monooxygenase. a novel methanotroph-specific community-profiling method was established using the terminal restriction fragment length polymorphism (t-rflp) technique. the t-rflp profiles clearly revealed a more complex root-associated methanot ... | 2001 | 11526021 |
| group-specific monitoring of phenol hydroxylase genes for a functional assessment of phenol-stimulated trichloroethylene bioremediation. | the sequences of the largest subunit of bacterial multicomponent phenol hydroxylases (lmphs) were compared. it was found that lmphs formed three phylogenetic groups, i, ii, and iii, corresponding to three previously reported kinetic groups, low-k(s) (the half-saturation constant in haldane's equation for trichloroethylene [tce]), moderate-k(s), and high-k(s) groups. consensus sequences and specific amino acid residues for each group of lmph were found, which facilitated the design of universal a ... | 2001 | 11571171 |
| family- and genus-level 16s rrna-targeted oligonucleotide probes for ecological studies of methanotrophic bacteria. | methanotrophic bacteria play a major role in the global carbon cycle, degrade xenobiotic pollutants, and have the potential for a variety of biotechnological applications. to facilitate ecological studies of these important organisms, we developed a suite of oligonucleotide probes for quantitative analysis of methanotroph-specific 16s rrna from environmental samples. two probes target methanotrophs in the family methylocystaceae (type ii methanotrophs) as a group. no oligonucleotide signatures t ... | 2001 | 11571178 |
| copper-induced inhibition of growth of desulfovibrio desulfuricans g20: assessment of its toxicity and correlation with those of zinc and lead. | the toxicity of copper [cu(ii)] to sulfate-reducing bacteria (srb) was studied by using desulfovibrio desulfuricans g20 in a medium (mtm) developed specifically to test metal toxicity to srb (r. k. sani, g. geesey, and b. m. peyton, adv. environ. res. 5:269-276, 2001). the effects of cu(ii) toxicity were observed in terms of inhibition in total cell protein, longer lag times, lower specific growth rates, and in some cases no measurable growth. at only 6 microm, cu(ii) reduced the maximum specifi ... | 2001 | 11571183 |
| genetic and functional analysis of the tbc operons for catabolism of alkyl- and chloroaromatic compounds in burkholderia sp. strain js150. | burkholderia sp. strain js150 is able to metabolize a wide range of alkyl-and chloroaromatic hydrocarbons through multiple, apparently redundant catabolic pathways. previous research has shown that strain js150 is able to synthesize enzymes for multiple upper pathways as well as multiple lower pathways to accommodate variously substituted catechols that result from degradation of complex mixtures of monoaromatic compounds. we report here the genetic organization and functional characterization o ... | 2001 | 11571188 |
| detection and enumeration of methanotrophs in acidic sphagnum peat by 16s rrna fluorescence in situ hybridization, including the use of newly developed oligonucleotide probes for methylocella palustris. | two 16s rrna-targeted oligonucleotide probes, mcell-1026 and mcell-181, were developed for specific detection of the acidophilic methanotroph methylocella palustris using fluorescence in situ hybridization (fish). the fluorescence signal of probe mcell-181 was enhanced by its combined application with the oligonucleotide helper probe h158. mcell-1026 and mcell-181, as well as 16s rrna oligonucleotide probes with reported group specificity for either type i methanotrophs (probes m-84 and m-705) o ... | 2001 | 11571193 |
| two distinct monooxygenases for alkane oxidation in nocardioides sp. strain cf8. | alkane monooxygenases in nocardioides sp. strain cf8 were examined at the physiological and genetic levels. strain cf8 can utilize alkanes ranging in chain length from c(2) to c(16). butane degradation by butane-grown cells was strongly inhibited by allylthiourea, a copper-selective chelator, while hexane-, octane-, and decane-grown cells showed detectable butane degradation activity in the presence of allylthiourea. growth on butane and hexane was strongly inhibited by 1-hexyne, while 1-hexyne ... | 2001 | 11679317 |
| membrane-associated quinoprotein formaldehyde dehydrogenase from methylococcus capsulatus bath. | a membrane-associated, dye-linked formaldehyde dehydrogenase (dl-faldh) was isolated from the obligate methylotroph methylococcus capsulatus bath. the enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 micromol of cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. soluble nad(p)(+)-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane mon ... | 2001 | 11698372 |
| requirement of dna repair mechanisms for survival of burkholderia cepacia g4 upon degradation of trichloroethylene. | a tn5-based mutagenesis strategy was used to generate a collection of trichloroethylene (tce)-sensitive (tcs) mutants in order to identify repair systems or protective mechanisms that shield burkholderia cepacia g4 from the toxic effects associated with tce oxidation. single tn5 insertion sites were mapped within open reading frames putatively encoding enzymes involved in dna repair (uvrb, ruvb, reca, and recg) in 7 of the 11 tcs strains obtained (4 of the tcs strains had a single tn5 insertion ... | 2001 | 11722883 |
| carbon and hydrogen stable isotope fractionation during aerobic bacterial degradation of aromatic hydrocarbons. | 13c/(12)c and d/h stable isotope fractionation during aerobic degradation was determined for pseudomonas putida strain mt-2, pseudomonas putida strain f1, ralstonia pickettii strain pko1, and pseudomonas putida strain ncib 9816 grown with toluene, xylenes, and naphthalene. different types of initial reactions used by the respective bacterial strains could be linked with certain extents of stable isotope fractionation during substrate degradation. | 2002 | 12324375 |
| purified particulate methane monooxygenase from methylococcus capsulatus (bath) is a dimer with both mononuclear copper and a copper-containing cluster. | particulate methane monooxygenase (pmmo) is a membrane-bound enzyme that catalyzes the oxidation of methane to methanol in methanotropic bacteria. understanding how this enzyme hydroxylates methane at ambient temperature and pressure is of fundamental chemical and potential commercial importance. difficulties in solubilizing and purifying active pmmo have led to conflicting reports regarding its biochemical and biophysical properties, however. we have purified pmmo from methylococcus capsulatus ... | 2003 | 12634423 |
| quantitative detection of methanotrophs in soil by novel pmoa-targeted real-time pcr assays. | methane oxidation in soils is mostly accomplished by methanotrophic bacteria. little is known about the abundance of methanotrophs in soils, since quantification by cultivation and microscopic techniques is cumbersome. comparison of 16s ribosomal dna and pmoa (alpha subunit of the particulate methane monooxygenase) phylogenetic trees showed good correlation and revealed five distinct groups of methanotrophs within the alpha and gamma subclasses of proteobacteria: the methylococcus group, the met ... | 2003 | 12732507 |
| wide distribution of a novel pmoa-like gene copy among type ii methanotrophs, and its expression in methylocystis strain sc2. | experiments were conducted to determine if a novel pmoa-like gene (pmoa2) recently discovered in the methane-oxidizing bacterium methylocystis strain sc2 (p. f. dunfield, m. tchawa yimga, s. d. dedysh, u. berger, w. liesack, and j. heyer, fems microbiol. ecol. 41:17-26, 2002) is present in other methane-oxidizing bacteria (mob), and if it is expressed. a newly developed primer combination (pmoa206f-pmoa703b) allowed a differential detection of pmoa1 and pmoa2. by using this primer combination, w ... | 2003 | 12957949 |
| diversity and activity of methanotrophic bacteria in different upland soils. | samples from diverse upland soils that oxidize atmospheric methane were characterized with regard to methane oxidation activity and the community composition of methanotrophic bacteria (mb). mb were identified on the basis of the detection and comparative sequence analysis of the pmoa gene, which encodes a subunit of particulate methane monooxygenase. mb commonly detected in soils were closely related to methylocaldum spp., methylosinus spp., methylocystis spp., or the "forest sequence cluster" ... | 2003 | 14602631 |