| 1h nmr studies of the paramagnetic cua center of cytochrome oxidase. | the dinuclear paramagnetic center of the soluble cua domain of the cytochrome c oxidase from bacillus subtilis has been studied using 1h nmr. the spectrum possesses remarkably sharp shifted resonances. comparison with the spectrum of the cua amicyanin variant provides the spin density distribution in the cua site of cytochrome c oxidase. this represents the first paramagnetic nmr study of the dinuclear cua center from the soluble domain of subunit ii of cytochrome c oxidase. | 1996 | 8830670 |
| a protein having similarity with methylmalonyl-coa mutase is required for the assimilation of methanol and ethanol by methylobacterium extorquens am1. | a 4.0 kb region of methylobacterium extorquens am1 dna which complements three mutants unable to convert acetyl-coa to glyoxylate (and therefore defective in the assimilation of methanol and ethanol) has been isolated and sequenced. it contains two orfs and the 3'-end of a third one. the mutations in all three mutants mapped within the first orf, which was designated meaa; it encodes a protein having similarity with methylmalonyl-coa mutase. however, methylmalonyl-coa mutase was measured in extr ... | 1996 | 8868443 |
| cloning and expression of the gene for serine-glyoxylate aminotransferase from an obligate methylotroph hyphomicrobium methylovorum gm2. | the gene encoding serine-glyoxylate aminotransferase, one of key enzymes for the assimilation of one-carbon compounds in methylotrophs, and its flanking regions were isolated from an obligate methylotrophic bacterium, hyphomicrobium methylovorum gm2. nucleotide sequencing of the recombinant plasmids revealed that the serine-glyoxylate aminotransferase gene encodes a 405-amino-acid protein with a calculated molecular mass of 43880 da. the amino acid sequence of the enzyme showed identity to the s ... | 1996 | 8898880 |
| multiparametric analysis of waterline contamination in dental units. | microbial contamination of dental unit waterlines is thought to be the result of biofilm formation within the small-bore tubing used for these conduits. systematic sampling of 121 dental units located at the dental school of université de montréal showed that none of the waterlines was spared from bacterial contamination. multilevel statistical analyses showed significant differences between samples taken at the beginning of the day and samples taken after a 2-min purge. differences were also fo ... | 1996 | 8899982 |
| reconstitution of the quinoprotein methanol dehydrogenase from inactive ca(2+)-free enzyme with ca2+, sr2+ or ba2+. | the reconstitution of active holoenzyme containing calcium from inactive calcium-free methanol dehydrogenase, isolated from a moxa mutant of methylobacterium extorquens, has a ph optimum of about ph 10, with a well defined pk for the process at ph 9.3. two ca2+ ions were irreversibly incorporated per alpha 2 beta 2 tetramer. calcium could be replaced in the incorporation process by strontium or barium, the affinities for these ions being similar to that for ca2+. arrhenius plots for measurement ... | 1996 | 8920988 |
| methylobacterium bacteremia after infusion of contaminated autologous bone marrow. | | 1996 | 8922835 |
| efficient l-serine production from methanol and glycine by resting cells of methylobacterium sp. strain mn43. | resting cells of methanol-utilizing microorganisms isolated from soils were examined for l-serine production under conditions in which l-serine-degradation was suppressed. strain mn43, a facultative methylotrophic bacterium identified as a methylobacterium sp., was selected for further studies. under the optimal conditions, 65 mg/ml l-serine was produced by this bacterium from 50 mg/ml glycine and 104 mg/ml methanol in 5 days, with a molar conversion ratio from glycine to l-serine of 93%. this p ... | 1996 | 8987658 |
| the methanol oxidation genes mxafjgir (s) ackld in methylobacterium extorquens. | mxaj is a protein of unknown function encoded by mxaj in the mxafjgi operon. we have constructed a mxaj mutant of m. extorquens with a deletion which does not affect transcription of downstream genes. it contained cytochrome cl (mxag), but neither subunit of methanol dehydrogenase (mxaf and mxai). mxaj is probably involved in processing this enzyme. we have sequenced the region between mxafjgi and five other methanol oxidation genes, mxaackld; it includes one open reading frame (mxar) and a poss ... | 1997 | 8997703 |
| the formate dehydrogenase isolated from the aerobe methylobacterium sp. rxm is a molybdenum-containing protein. | the formate dehydrogenase (fdh) isolated from cells of methylobacterium sp. rxm grown on molybdenum-containing mineral medium using methanol as carbon source, was partially purified (at least 90% pure as revealed by sds-page). the enzyme is unstable under oxygen and all the purification steps were conducted under strict anaerobic conditions. the molecular mass is 75 kda (gel exclusion 300 kda). the enzyme was characterized in terms of the kinetic parameters towards different substrates and elect ... | 1997 | 9020054 |
| biodegradation of methyl t-butyl ether by pure bacterial cultures. | three pure bacterial cultures degrading methyl t-butyl ether (mtbe) were isolated from activated sludge and fruit of the gingko tree. they have been classified as belonging to the genuses methylobacterium, rhodococcus, and arthrobacter. these cultures degraded 60 ppm mtbe in 1-2 weeks of incubation at 23-25 degrees c. the growth of the isolates on mtbe as sole carbon source is very slow compared with growth on nutrient-rich medium. uniformly-labeled [14c]mtbe was used to determine 14co2 evolutio ... | 1997 | 9035411 |
| sequence analysis of pqq genes required for biosynthesis of pyrroloquinoline quinone in methylobacterium extorquens am1 and the purification of a biosynthetic intermediate. | methylobacterium extorquens am1 produces pyrroloquinoline quinone (pqq), the prosthetic group of methanol dehydrogenase. two genes clusters have been shown to be required for pqq biosynthesis in this micro-organism and complementation analysis has identified seven pqq genes, pqqdgcba and pqqef. the dna sequence of pqqdgc' was reported previously. this paper reports the sequence of the genomic region corresponding to pqqc'ba. for consistency, the nomenclature of pqq genes in klebsiella pneumoniae ... | 1997 | 9043136 |
| [the effect of long-acting radiation on the diversity of heterotrophic bacteria in the soils of a 10-kilometer area around the chernobyl atomic electric power station]. | the catastrophe at chernobyl atomic power station (chaps) of 1986 has created a natural model for studying the after-effects of prolonged action of radiation on the biota. our work is aimed to estimate the variability of heterotrophic bacteria in the soil of 10-km zone of chaps which have formed as affected by prolonged action of radiation, as well as to create the corresponding collection of bacteria. microbiological analysis of soils was carried out in 1993-1994 (in spring, summer, autumn), al ... | 1996 | 9044711 |
| mercury-responsive gene regulation and mercury-199 as a probe of protein structure. | | 1997 | 9046582 |
| competition between beta-ketothiolase and citrate synthase during poly(beta-hydroxybutyrate) synthesis in methylobacterium rhodesianum. | the enzymes beta-ketothiolase and citrate synthase from the facultatively methylotrophic methylobacterium rhodesianum mb 126, which uses the serine pathway, were purified and characterized. the beta-ketothiolase had a relatively high km for acetyl-coa (0.5 mm) and was strongly inhibited by coa (ki 0.02 mm). the citrate synthase had a much higher affinity for acetyl-coa (km 0.07 mm) and was significantly inhibited by nadh (ki 0.15 mm). the intracellular concentration of coa metabolites and nucleo ... | 1996 | 9082918 |
| transformation of methylotrophic bacteria by electroporation. | an efficient system for electroporation of the methylotrophic bacteria hyphomicrobium facilis, hyphomicrobium denitrificans, methylobacillus glycogenes, methylobacterium extorquens, and methylophilus methylotrophus is described. it could be demonstrated that vectors based on the broad-host-range plasmid pbbr1 could be transferred into these strains. plasmid pbbr1kan (3.9 kb), a kanamycin-resistant derivative of pbbr1, was suitable for transformation experiments in these methylotrophic bacteria. ... | 1997 | 9090108 |
| analysis of the pha granule-associated proteins ga20 and ga11 in methylobacterium extorquens and methylobacterium rhodesianum. | electrophoretic analysis of the proteins bound to poly(3-hydroxybutyric acid), phb-, granules in methylobacterium extorquens, m. rhodesianum as well as the phb-leaky mutants mu 1 and mu 11, which were isolated from the latter, resulted in two dominant low-molecular weight proteins, which were referred to as ga11 and ga20. after purification of these proteins antibodies against the ga11 and ga20 protein of m. extorquens were obtained. both proteins bound to the surface of phb granules as revealed ... | 1997 | 9090123 |
| detection of methylobacterium species by 16s rrna gene-targeted pcr. | we designed pcr primers for specific amplification of the 16s rrna genes of seven species of the genus methylobacterium. all of the pairwise species tested were successfully differentiated by pcr detection with a combination of five primer sets, with the exception of m. extorquens and m. rhodesianum. these primers did not cross-react with closely related bacteria in the alpha subclass tested. | 1997 | 9097454 |
| purification and characterization of citrate synthase from methylobacterium extorquens--a methylotrophic producer of polyhydroxybutyrate. | citrate synthase (citrate oxaloacetate-lyase, coa-acetylating; ec 4.1.3.7, cs) was isolated and purified to homogeneity from a methylotrophic producer of polyhydroxybutyrate (phb), methylobacterium extorquens 15. the purification procedure includes streptomycin sulfate treatment of cell-free extract, ammonium sulfate fractionation, two steps of hydrophobic chromatography, and ion-exchange chromatography. the specific activity of the final enzyme preparation was 24 u/mg protein. the enzyme has ap ... | 1997 | 9113733 |
| a 1h nmr study of the paramagnetic active site of the cua variant of amicyanin. | the dinuclear paramagnetic center of the cua variant of the cupredoxin amicyanin has been investigated using 1h nmr. the hyperfine-shifted resonances have been assigned using a combination of 1d noe difference and 2d weft-noesy spectroscopy. the shifts experienced by the assigned resonances have been used to calculate hyperfine coupling constants for these protons from which the spin density distribution on the ligands at the cua center is obtained. a comparison with published data for the param ... | 1997 | 9116004 |
| sequence and functional analysis of an escherichia coli dna fragment able to complement pqqe and pqqf mutants from methylobacterium organophilum. | a 7361 kb fragment of e coli chromosomal dna able to complement pqqe and pqqf mutants of methylobacterium organophilum has been sequenced. five open reading frames (orf) have been identified. four orfs (102, 103, 106 and 107), belong to a single transcription unit. they are separated by a transcription termination site from a fifth orf (orf109). polypeptides of 28, 85 and 82 kda encoded by orfs 102, 103 and 106 respectively were visualised in maxi-cell experiments. both orf106 and orf107 are req ... | 1996 | 9116051 |
| methylobacterium mesophilicum synovitis in an alcoholic. | | 1997 | 9142814 |
| erratum to "the methanol oxidation genes mxafjgir (s) ackld in methylobacterium extorquens" [fems microbiol. lett. 146 (1997) 31-38]. | | 1997 | 9163922 |
| molecular and mutational analysis of a dna region separating two methylotrophy gene clusters in methylobacterium extorquens am1. | a region of 14.2 kb has been analysed that is a part of a locus on the methylobacterium extorquens am1 chromosome containing a number of genes involved in one-carbon (c1) metabolism, including serine cycle genes, pqq genes, regulatory methanol oxidation genes and the gene for n5,n10-methylene tetrahydrofolate dehydrogenase (mtda). fifteen new orfs have been identified within the new region, and their sequences suggest that they encode the following polypeptides: the c-terminal part of phosphoeno ... | 1997 | 9168622 |
| molecular analysis of mxbd and mxbm, a putative sensor-regulator pair required for oxidation of methanol in methylobacterium extorquens am1. | five genes are thought to be required for transcription of methanol oxidation genes in methylobacterium strains. these putative regulatory genes include mxcqe, which encode a putative sensor-regulator pair, and mxbdm and mxab, whose functions are less well-understood. in this study, mxbdm in methylobacterium extorquens am1 were shown to be required for expression of a xyle transcriptional fusion to the structural gene for the large subunit of methanol dehydrogenase (mxaf), confirming the role of ... | 1997 | 9168623 |
| organization of methylamine utilization genes (mau) in 'methylobacillus flagellatum ' kt and analysis of mau mutants. | the organization of genes involved in utilization of methylamine (mau genes) was studied in the obligate methylotroph 'methylobacillus flagellatum' kt. nine open reading frames were identified as corresponding to the genes maufbedaglmn. in addition, an open reading frame (orf-1 encoding a polypeptide with unknown function was identified upstream of the mau gene cluster. subclones of the 'm. flagellatum' kt gene cluster were used for complementation of a series of chemically induced mau mutants o ... | 1997 | 9202457 |
| identification and mutation of a gene required for glycerate kinase activity from a facultative methylotroph, methylobacterium extorquens am1. | a gene (gcka) responsible for the activity of glycerate kinase has been identified within a chromosomal fragment of the serine cycle methylotroph methylobacterium extorquens am1. a mutation in gcka leads to a specific c1-negative phenotype. the polypeptide sequence derived from gcka showed high similarity to a product of ttud essential for tartrate metabolism in agrobacterium vitis. our data suggest that gcka and ttud might be structural genes for glycerate kinase and that the serine cycle and t ... | 1997 | 9244287 |
| a novel alternate anaplerotic pathway to the glyoxylate cycle in streptomycetes. | ccr encoding crotonyl coenzyme a (coa) reductase (ccr), which catalyzes the conversion of crotonyl-coa to butyryl-coa in the presence of nadph, was previously cloned from streptomyces collinus. we now report that a complete open reading frame, designated meaa, is located downstream from ccr. the predicted gene product showed 35% identity with methylmalonyl-coa mutases from various sources. in addition, the predicted amino acid sequences of s. collinus ccr and meaa exhibit strong similarity to th ... | 1997 | 9260959 |
| alkaline transition of rhus vernicifera stellacyanin, an unusual blue copper protein. | stellacyanin from rhus vernificera is a blue copper protein in which the metal is coordinated to a cys, two his, and a gln residue. it displays a low redox potential, a fast electron exchange rate, and a reversible alkaline transition. we have studied this transition in cu(ii)- and co(ii)-stellacyanin by means of electronic and nmr spectroscopy. the data indicate that a conformational rearrangement of the metal site occurs at high ph. a drastic alteration in the gln coordination mode, as initial ... | 1997 | 9265638 |
| identification of a novel determinant of glutathione affinity in dichloromethane dehalogenases/glutathione s-transferases. | bacterial dichloromethane dehalogenases catalyze the glutathione-dependent hydrolysis of dichloromethane to formaldehyde and are members of the enzyme superfamily of glutathione s-transferases involved in the detoxification of electrophilic compounds. numerous protein engineering studies have addressed questions pertaining to the substrate specificity, the reaction mechanism, and the kinetic pathway of glutathione s-transferases. in contrast, the molecular determinants for binding of the glutath ... | 1997 | 9299530 |
| cloning and analysis of methanol oxidation genes in the methylotroph hyphomicrobium methylovorum gm2. | the gene encoding the alpha-subunit of methanol dehydrogenase (mxaf) and its flanking region was isolated from a methylotrophic bacterium, hyphomicrobium methylovorum gm2. the deduced amino acid sequence of mxaf showed 80, 80, 74 and 66% identity with those of methylobacterium extorquens am1, m. organophilum xx, paracoccus denitrificans and methylophilus methylotrophus, respectively. the putative mxaf promoter sequence (-35 -aaagaca-, -10 -tagaa-) observed in other methylotrophs was not found in ... | 1997 | 9311140 |
| purification and properties of methanol dehydrogenase from methylocystis sp. gb 25. | methanol dehydrogenase (mdh) from methylocystis sp. gb 25, which belongs to the group ii of methanotrophic bacteria, is able to catalyse the oxidation of methanol to formate directly. the enzyme was purified 20-fold by a 5 step procedure to electrophoretic homogeneity. after cell disruption by french press, about 95% of mdh-activity was found in the soluble fraction. the relative molecular mass of the native enzyme has been estimated to be 122 kda by gel filtration and 115 kda by the method of h ... | 1997 | 9323867 |
| factors which stabilize the methylamine dehydrogenase-amicyanin electron transfer protein complex revealed by site-directed mutagenesis. | methylamine dehydrogenase (madh) and amicyanin form a physiologic complex within which electrons are transferred from the tryptophan tryptophylquinone (ttq) cofactor of madh to the type 1 copper of amicyanin. interactions responsible for complex formation may be inferred from the crystal structures of complexes of these proteins. site-directed mutagenesis has been performed to probe the roles of specific amino acid residues of amicyanin in stabilizing the madh-amicyanin complex and determining t ... | 1997 | 9335529 |
| catalytic role of monovalent cations in the mechanism of proton transfer which gates an interprotein electron transfer reaction. | within the methylamine dehydrogenase (madh)-amicyanin protein complex, long range intermolecular electron transfer (et) occurs between tryptophan tryptophylquinone (ttq) of madh and the type i copper of amicyanin. the reoxidations of two chemically distinct reduced forms of ttq were studied, a quinol (o-quinol) generated by reduction by dithionite and the physiologically relevant aminoquinol (n-quinol) generated by reduction by methylamine. the latter contains a substrate-derived amino group whi ... | 1997 | 9354627 |
| intermediate sequences increase the detection of homology between sequences. | two homologous sequences, which have diverged beyond the point where their homology can be recognised by a simple direct comparison, can be related through a third sequence that is suitably intermediate between the two. high scores, for a sequence match between the first and third sequences and between the second and the third sequences, imply that the first and second sequences are related even though their own match score is low. we have tested the usefulness of this idea using a database that ... | 1997 | 9367767 |
| methylobacterium mesophilica as a cause of persistent bacteremia in a child with lymphoma. | | 1997 | 9380457 |
| heterologous expression of heterotrophic nitrification genes. | paracoccus denitrificans is a heterotrophic organism capable of oxidizing ammonia to nitrite during growth on an organic carbon and energy source. this pathway, termed heterotrophic nitrification, requires the concerted action of an ammonia monooxygenase (amo) and hydroxylamine oxidase (hao). the genes required for heterotrophic nitrification have been isolated by introducing a pa. denitrificans genomic library into pseudomonas putida and screening for the accumulation of nitrite. in contrast to ... | 1997 | 9421902 |
| a novel pink-pigmented facultative methylotroph, methylobacterium thiocyanatum sp. nov., capable of growth on thiocyanate or cyanate as sole nitrogen sources. | the isolation and properties of a novel species of pink-pigmented methylotroph, methylobacterium thiocyanatum, are described. this organism satisfied all the morphological, biochemical, and growth-substrate criteria to be placed in the genus methylobacterium. sequencing of the gene encoding its 16s rrna confirmed its position in this genus, with its closest phylogenetic relatives being m. rhodesianum, m. zatmanii and m. extorquens, from which it differed in its ability to grow on several diagnos ... | 1998 | 9446686 |
| a new insertion sequence from sinorhizobium meliloti with homology to is1357 from methylobacterium sp. and is1452 from acetobacter pasteurianus. | the insertion sequence isrm8 was identified by sequence analysis of the cryptic plasmid prmegr4b of sinorhizobium meliloti gr4. isrm8 is 1451 bp in length and carries 22/24-bp terminal imperfect inverted repeats with seven mismatches and a direct target site duplication of 3 bp. isrm8 carries a unique open reading frame whose putative protein showed significant similarity to the insertion sequences is1357 and is1452, isolated from methylobacterium sp. and acetobacter pasteurianus, respectively. ... | 1998 | 9453160 |
| an rna polymerase preparation from methylobacterium extorquens am1 capable of transcribing from a methylotrophic promoter. | rna polymerase (rnap) was purified from methylobacterium extorquens am1 cells grown on methanol or on succinate. the beta, beta', alpha and omega subunits were approximately the same size as those of escherichia coli, and the identity of the omega subunit was confirmed by n-terminal sequence analysis. n-terminal sequence analysis suggested that two other polypeptides in the purified rnap preparation might be sigma factors, a 40 kda polypeptide that shared identity with sigma 32 homologues, and a ... | 1998 | 9467910 |
| pqqa is not required for biosynthesis of pyrroloquinoline quinone in methylobacterium extorquens am1. | methylobacterium extorquens am1 is a facultative methylotroph that oxidizes methanol via the pyrroloquinoline quinone (pqq)-linked enzyme methanol dehydrogenase. in m. extorquens am1 and other pqq-synthesizing bacteria, several genes are involved in the synthesis of pqq and one of these, pqqa, has been proposed to encode a peptide precursor of pqq. in other pqq-synthesizing bacteria, pqqa is required for pqq production. in this study, it is shown that both deletion and insertion mutants of pqqa ... | 1998 | 9467911 |
| sequence and characterization of mxab, a response regulator involved in regulation of methanol oxidation, and of mxaw, a methanol-regulated gene in methylobacterium extorquens am1. | in the facultative serine cycle methylotroph methylobacterium extorquens am1, mxab is required for regulation of methanol oxidation and is located at the end of a large cluster of methylotrophy genes that begins with mxaf. the sequence of mxab has been obtained and indicates that the gene product is a member of the response regulator family. none of the open reading frames near mxab showed sequence identity to sensor kinases. complementation studies suggest a promoter may be located adjacent to ... | 1998 | 9495022 |
| regulation of poly(beta-hydroxybutyrate) synthesis in methylobacterium rhodesianum mb 126 growing on methanol or fructose. | the intracellular concentration of coa metabolites and nucleotides was determined in batch cultures of methylobacterium rhodesianum grown on methanol and shifted to growth on fructose. the intracellular concentration of coa decreased from a high value of 0.6 nmol/mg poly(beta-hydroxybutyrate)-free bacterial dry mass during growth on methanol to a low value of 0.03 nmol/mg poly(beta-hydroxybutyrate)-free bacterial dry mass after a shift to fructose as a carbon source. the levels of nadh, nadph, a ... | 1998 | 9531638 |
| 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 |
| biodegradation of metal-edta complexes by an enriched microbial population. | a mixed culture utilizing edta as the sole carbon source was isolated from a mixed inoculum of water from the river mersey (united kingdom) and sludge from an industrial effluent treatment plant. fourteen component organisms were isolated from the culture, including representatives of the genera methylobacterium, variovorax, enterobacter, aureobacterium, and bacillus. the mixed culture biodegraded metal-edta complexes slowly; the biodegradability was in the order fe > cu > co > ni > cd. by incor ... | 1998 | 9546167 |
| chloromethane metabolism by methylobacterium sp. strain cm4 | methylobacterium sp. strain cm4 metabolized chloromethane quantitatively with a molar yield of 2.8 g of whole-cell protein/mol of c. this value was similar to that observed after growth with methanol (2.9 g of protein/mol of c) and about three times larger than the yield with formate (0.94 g of protein/mol of c). chloromethane dehalogenation activity was inducible. minitn5 transposon insertion mutants with altered growth characteristics with chloromethane and other c1 compounds were isolated and ... | 1998 | 9572975 |
| site-directed mutagenesis of phe 97 to glu in amicyanin alters the electronic coupling for interprotein electron transfer from quinol methylamine dehydrogenase. | conversion by site-directed mutagenesis of phe 97 of amicyanin to glu significantly decreases the rate constant for the electron-transfer reaction from the quinol form of methylamine dehydrogenase to amicyanin. it is shown that the deltag degrees and reorganizational energy (lambda) associated with the electron-transfer reaction are unaffected by the mutation and that the decrease in the electron-transfer rate is attributable completely to a decrease in the electronic coupling matrix element (ha ... | 1998 | 9585551 |
| homology model of the quinohaemoprotein alcohol dehydrogenase from comamonas testosteroni. | a molecular model of qh-adh, the quinohaemoprotein alcohol dehydrogenase from comamonas testosteroni, has been built by homology modelling. sequence similarity of n-terminal residues 1-570 with the alpha-subunit of quinoprotein methanol dehydrogenases (mdhs) from methylophilus methylotrophus w3a1 and methylobacterium extorquens provided a basis for the design of the pqq-binding domain of qh-adh. minimal sequence similarity with cytochrome c551 from ectothiorhodospira halophila and cytochrome c5 ... | 1998 | 9613842 |
| the effect of the simultaneous addition of molybdenum and tungsten to the culture medium on the formate dehydrogenase activity from methylobacterium sp. rxm | shake flask cultivation of the facultative methylotroph methylobacterium sp. rxm was carried out by using a statistical experimental design to investigate the role of metal association on the formate dehydrogenase (fdh) levels. the maximal values of fdh activity were obtained for tungsten concentration up to 0.6 µm and for molybdenum concentration between 0.6 and 0.9 µm. the negative polynomial parameter (beta2) for tungsten compared with the positive polynomial parameter (beta1) for molybdenum ... | 1998 | 9645920 |
| c1 transfer enzymes and coenzymes linking methylotrophic bacteria and methanogenic archaea. | methanogenic and sulfate-reducing archaea are considered to have an energy metabolism involving c1 transfer coenzymes and enzymes unique for this group of strictly anaerobic microorganisms. an aerobic methylotrophic bacterium, methylobacterium extorquens am1, was found to contain a cluster of genes that are predicted to encode some of these enzymes and was shown to contain two of the enzyme activities and one of the methanogenic coenzymes. insertion mutants were all unable to grow on c1 compound ... | 1998 | 9651254 |
| [ecological consequences of radioactive pollution for soil bacteria within the 10-km region around the chernobyl atomic energy station]. | the diversity of aerobic chemoorganotrophic (capable of growing on nutrient agar) bacteria in radioactive soil (0.3-17.0 microci/kg soil) sampled in the 10-km zone around the chernobyl nuclear power plant (cnpp) was found to be lower than that observed in control, uncontaminated soil with a radioactivity of 0.002-0.006 microci/kg soil. all the radioactive soil samples contained the bacteria bacillus cereus and methylobacterium extorquens or m. mesophillicum, which exhibited a high tolerance to 0 ... | 1998 | 9662700 |
| electron transfer from the aminosemiquinone reaction intermediate of methylamine dehydrogenase to amicyanin. | the tryptophan tryptophylquinone (ttq) cofactor of methylamine dehydrogenase (madh) is covalently modified by substrate-derived nitrogen during its two-electron reduction by methylamine to form an aminoquinol (n-quinol). an n-semiquinone, which retains the substrate-derived n, is the intermediate during the two sequential one-electron oxidations of n-quinol madh by its physiologic electron acceptor, amicyanin. electron transfer (et) from n-quinol madh to amicyanin is gated by the deprotonation o ... | 1998 | 9692997 |
| microbial communities of printing paper machines. | the microbial content of printing paper machines, running at a temperature of 45-50 degrees c and at ph 4.5-5, was studied. bacteria were prevalent colonizers of the machine wet end and the raw materials. a total of 390 strains of aerobic bacteria were isolated and 86% of these were identified to genus and species by biochemical, chemotaxonomic and phylogenetic methods. the most common bacteria found at the machine wet end were bacillus coagulans and other bacillus species, burkholderia cepacia, ... | 1998 | 9717292 |
| production of poly-3-hydroxybutyrate from lactose and whey by methylobacterium sp. zp24. | methylobacterium sp. zp24, isolated from a local pond, is able to grow in a medium containing 12 g l-1 lactose as a sole source of carbon, giving 5.25 g l-1 biomass yield and poly-3-hydroxybutyrate (phb) up to 59% of its dry weight in 40 h. the isolate was also able to utilize cheese whey and produce 1.1 g l-1 phb. addition of ammonium sulphate increased the production of phb from whey 2.5-fold. the potential of methylobacterium sp. zp24 in phb production from cheese whey is discussed. | 1998 | 9717306 |
| construction of insertion and deletion mxa mutants of methylobacterium extorquens am1 by electroporation. | methylobacterium extorquens am1 is a pink-pigmented facultative methylotroph which is widely used for analyzing pathways of c1 metabolism with biochemical and molecular biological techniques. to facilitate this approach, we have applied a new method to construct insertion or disruption mutants with drug resistance genes by electroporation. by using this method, mutants were obtained in four genes present in the mxa methylotrophy gene cluster for which the functions were unknown, mxar, mxas, mxac ... | 1998 | 9741078 |
| crystallographic and spectroscopic studies of native, aminoquinol, and monovalent cation-bound forms of methylamine dehydrogenase from methylobacterium extorquens am1. | various monovalent cations influence the enzymatic activity and the spectroscopic properties of methylamine dehydrogenase (madh). here, we report the structure determination of this tryptophan tryptophylquinone-containing enzyme from methylobacterium extorquens am1 by high resolution x-ray crystallography (1.75 a). this first madh crystal structure at low ionic strength is compared with the high resolution structure of the related madh from paracoccus denitrificans recently reported. we also des ... | 1998 | 9748238 |
| gene synthesis, expression, and mutagenesis of zucchini mavicyanin: the fourth ligand of blue copper center is gln. | the gene coding for the 109-amino-acid, non-glycosylated form of mavicyanin was synthesized and expressed in escherichia coli. the recombinant protein refolded from e. coli inclusion bodies was purified and characterized. its spectroscopic properties are fully identical to those of mavicyanin isolated from zucchini, even in the absence of its carbohydrate moiety. the blue cooper center of mavicyanin strongly binds three ligands (2his and cys) as well as many blue copper proteins. to disclose the ... | 1998 | 9753643 |
| the nadp-dependent methylene tetrahydromethanopterin dehydrogenase in methylobacterium extorquens am1. | an nadp-dependent methylene tetrahydromethanopterin (h4mpt) dehydrogenase has recently been proposed to be involved in formaldehyde oxidation to co2 in methylobacterium extorquens am1. we report here on the purification of this novel enzyme to apparent homogeneity. via the n-terminal amino acid sequence, it was identified to be the mtda gene product. the purified enzyme catalyzed the dehydrogenation of methylene h4mpt with nadp+ rather than with nad+, with a specific activity of approximately 40 ... | 1998 | 9765566 |
| molecular structure of an unusual cytochrome c2 determined at 2.0 a; the cytochrome ch from methylobacterium extorquens. | | 1998 | 9765929 |
| 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 |
| quinoprotein ethanol dehydrogenase of pseudomonas aeruginosa is a homodimer--sequence of the gene and deduced structural properties of the enzyme. | the gene coding for the periplasmic quinoprotein ethanol dehydrogenase of pseudomonas aeruginosa atcc 17933 was cloned and sequenced. the deduced amino acid sequence contained a signal peptide of 34 residues and the major protein of 589 amino acids showed high similarities to pyrroloquinoline-quinone-dependent periplasmic and membrane-bound dehydrogenases acting on alcohols, glucose and quinate or shikimate. it was demonstrated by alignment with the amino acid sequence of the large subunit of th ... | 1998 | 9826187 |
| methylopila capsulata gen. nov., sp. nov., a novel non-pigmented aerobic facultatively methylotrophic bacterium. | a new genus, methylopila, and one new species are described for a group of seven strains of facultatively methylotrophic bacteria with the serine pathway of c1 assimilation. these bacteria are aerobic, gram-negative, non-spore--forming, motile, colourless rods that multiply by binary fission. their dna base content ranges from 66 to 70 mol % g + c. their cellular fatty acid profile consists primarily of c18:1 omega 7 cis-vaccenic and c19:0 cyclopropane acids. the major hydroxy acid is 3-oh c14:0 ... | 1998 | 9828432 |
| systemic infection of an immunocompromised patient with methylobacterium zatmanii. | we describe the identification of methylobacterium zatmanii as the causative agent of bacteremia and fever in an immunocompromised patient. the patient, a 60-year-old man, had a 5-month history of acute myeloid leukemia and had been on chemotherapy throughout this period. seven days after the onset of neutropenia, the patient developed fever. the combination of ciprofloxacin, co-trimoxazole, imipenem, amikacin, and vancomycin led to a complete defervescence. on subculture from six positive blood ... | 1999 | 9854105 |
| molecular basis for interprotein complex-dependent effects on the redox properties of amicyanin. | the quinoprotein methylamine dehydrogenase (madh), type i copper protein amicyanin, and cytochrome c-551i form a complex within which interprotein electron transfer occurs. it was known that complex formation significantly lowered the oxidation-reduction midpoint potential (em) value of amicyanin, which facilitated an otherwise thermodynamically unfavorable electron transfer to cytochrome c-551i. structural, mutagenesis, and potentiometric studies have elucidated the basis for this complex-depen ... | 1998 | 9860825 |
| quantum chemical calculations of the reorganization energy of blue-copper proteins. | the inner-sphere reorganization energy for several copper complexes related to the active site in blue-copper protein has been calculated with the density functional b3lyp method. the best model of the blue-copper proteins, cu(im)2(sch3)(s(ch3)2)(0/+), has a self-exchange inner-sphere reorganization energy of 62 kj/mol, which is at least 120 kj/mol lower than for cu(h2o)4(+/2+). this lowering of the reorganization energy is caused by the soft ligands in the blue-copper site, especially the cyste ... | 1998 | 9865961 |
| the biochemistry, physiology and genetics of pqq and pqq-containing enzymes. | pyrrolo-quinoline quinone (pqq) is the non-covalently bound prosthetic group of many quinoproteins catalysing reactions in the periplasm of gram-negative bacteria. most of these involve the oxidation of alcohols or aldose sugars. pqq is formed by fusion of glutamate and tyrosine, but details of the biosynthetic pathway are not known; a polypeptide precursor in the cytoplasm is probably involved, the completed pqq being transported into the periplasm. in addition to the soluble methanol dehydroge ... | 1998 | 9889976 |
| methylamine dehydrogenase: structure and function of electron transfer complexes. | | 1999 | 10093734 |
| location and survival of leaf-associated bacteria in relation to pathogenicity and potential for growth within the leaf | the growth and survival of pathogenic and nonpathogenic pseudomonas syringae strains and of the nonpathogenic species pantoea agglomerans, stenotrophomonas maltophilia, and methylobacterium organophilum were compared in the phyllosphere of bean. in general, the plant pathogens survived better than the nonpathogens on leaves under environmental stress. the sizes of the total leaf-associated populations of the pathogenic p. syringae strains were greater than the sizes of the total leaf-associated ... | 1999 | 10103233 |
| identification of a new reaction intermediate in the oxidation of methylamine dehydrogenase by amicyanin. | the two-electron oxidation of tryptophan tryptophylquinone (ttq) in substrate-reduced methylamine dehydrogenase (madh) by amicyanin is known to proceed via an n-semiquinone intermediate in which the substrate-derived amino group remains covalently attached to ttq [bishop, g. r., and davidson, v. l. (1996) biochemistry 35, 8948-8954]. a new method for the stoichiometric formation of the n-semiquinone in vitro has allowed the study of the oxidation of the n-semiquinone by amicyanin in greater deta ... | 1999 | 10200175 |
| a corrinoid-dependent catabolic pathway for growth of a methylobacterium strain with chloromethane. | methylobacterium sp. strain cm4, an aerobic methylotrophic alpha-proteobacterium, is able to grow with chloromethane as a carbon and energy source. mutants of this strain that still grew with methanol, methylamine, or formate, but were unable to grow with chloromethane, were previously obtained by minitn5 mutagenesis. the transposon insertion sites in six of these mutants mapped to two distinct dna fragments. the sequences of these fragments, which extended over more than 17 kb, were determined. ... | 1999 | 10200311 |
| a methenyl tetrahydromethanopterin cyclohydrolase and a methenyl tetrahydrofolate cyclohydrolase in methylobacterium extorquens am1. | recently it was found that methylobacterium extorquens am1 contains both tetrahydromethanopterin (h4mpt) and tetrahydrofolate (h4f) as carriers of c1 units. in this paper we report that the aerobic methylotroph contains a methenyl h4mpt cyclohydrolase (0.9 u x mg-1 cell extract protein) and a methenyl h4f cyclohydrolase (0.23 u x mg-1). both enzymes, which were specific for their substrates, were purified and characterized and the encoding genes identified via the n-terminal amino acid sequence. ... | 1999 | 10215859 |
| enzyme-mediated dichloromethane toxicity and mutagenicity of bacterial and mammalian dichloromethane-active glutathione s-transferases. | the kinetic properties of bacterial and rat liver glutathione s-transferases (gst) active with dichloromethane (dcm) were compared. the theta class glutathione s-transferase (rgstti-1) from rat liver had an affinity for dihalomethanes lower by three orders of magnitude (k(app) > 50 mm) than the bacterial dcm dehalogenase/gst from methylophilus sp. dm11. unlike the bacterial dcm dehalogenase, the rat enzyme was unable to support growth of the dehalogenase minus methylobacterium sp. dm4-2cr mutant ... | 1999 | 10350186 |
| the molecular structure of an unusual cytochrome c2 determined at 2.0 a; the cytochrome ch from methylobacterium extorquens. | cytochrome ch is the electron donor to the oxidase in methylotrophic bacteria. its amino acid sequence suggests that it is a typical class 1 cytochrome c, but some features of the sequence indicated that its structure might be of special interest. the structure of oxidized cytochrome ch has been solved to 2.0 a resolution by x-ray diffraction. it has the classical tertiary structure of the class 1 cytochromes c but bears a closer gross resemblance to mitochondrial cytochrome c than to the bacter ... | 1999 | 10386873 |
| protein strain in blue copper proteins studied by free energy perturbations. | free energy perturbations have been performed on two blue copper proteins, plastocyanin and nitrite reductase. by changing the copper coordination geometry, force constants, and charges, we have estimated the maximum energy with which the proteins may distort the copper coordination sphere. by comparing this energy with the quantum chemical energy cost for the same perturbation on the isolated copper complex, various hypotheses about protein strain have been tested. the calculations show that th ... | 1999 | 10398364 |
| heterologous expression of correctly assembled methylamine dehydrogenase in rhodobacter sphaeroides. | the biosynthesis of methylamine dehydrogenase (madh) from paracoccus denitrificans requires four genes in addition to those that encode the two structural protein subunits, maub and maua. the accessory gene products appear to be required for proper export of the protein to the periplasm, synthesis of the tryptophan tryptophylquinone (ttq) prosthetic group, and formation of several structural disulfide bonds. to accomplish the heterologous expression of correctly assembled madh, eight genes from ... | 1999 | 10400578 |
| the occurrence and persistence of mixed biofilms in automobile air conditioning systems. | twelve automobile air conditioner systems from six manufacturers and three countries, selected mostly because of complaints of unpleasant odors in the passenger compartment, were examined for microbial growth by direct microscopy and enrichment culture. mixed populations of fungi and bacteria (with occasional protozoa) were observed in biofilms in at least some of the components from all used units. the aluminum heat exchanger fins from ten evaporators demonstrated bacterial biofilms that yielde ... | 1999 | 10441727 |
| properties of the methylcobalamin:h4folate methyltransferase involved in chloromethane utilization by methylobacterium sp. strain cm4. | methylobacterium sp. strain cm4 is a strictly aerobic methylotrophic proteobacterium growing with chloromethane as the sole carbon and energy source. genetic evidence and measurements of enzyme activity in cell-free extracts have suggested a multistep pathway for the conversion of chloromethane to formate. the postulated pathway is initiated by a corrinoid-dependent methyltransferase system involving methyltransferase i (cmua) and methyltransferase ii (cmub), which transfer the methyl group of c ... | 1999 | 10447694 |
| methylobacterium extorquens strain p14, a new methylotrophic bacteria producing poly-beta-hydroxybutyrate (phb). | strain p14 of facultative methylotrophic bacteria that synthetisizes poly-beta-hydroxybutyrate has been isolated. the cells are gram-negative motile rods with a polar flagellum. they do not form spores or capsules, but do have a caretenoid pigment. predominant in the fatty acid composition of the cells is cis-vaccenic acid (cis 18:1: omega 7)--72%. in the phospholipid composition phosphatidylcholine predominates (45%), along with phosphatidylenthanoloamine (27%) and phosphatidylglycerol (17%). t ... | 1999 | 10467695 |
| 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 |
| halomethane:bisulfide/halide ion methyltransferase, an unusual corrinoid enzyme of environmental significance isolated from an aerobic methylotroph using chloromethane as the sole carbon source. | a novel dehalogenating/transhalogenating enzyme, halomethane:bisulfide/halide ion methyltransferase, has been isolated from the facultatively methylotrophic bacterium strain cc495, which uses chloromethane (ch(3)cl) as the sole carbon source. purification of the enzyme to homogeneity was achieved in high yield by anion-exchange chromatography and gel filtration. the methyltransferase was composed of a 67-kda protein with a corrinoid-bound cobalt atom. the purified enzyme was inactive but was act ... | 1999 | 10508052 |
| paramagnetic nmr studies of blue and purple copper proteins. | 1h- and 13c-nmr spectroscopy is applied to investigate the cu(a) and type 1 active sites of copper proteins in solution. the analysis of hyperfine shifted 1h resonances allows the comparison of the electron spin density delocalization in the cu(a) site of the wild-type soluble domains of various cytochrome c oxidases (thermus thermophilus, paracoccus denitrificans, and paracoccus versutus) and genetically engineered constructs (soluble domain of quinol oxidase from escherichia coli and thiobacil ... | 1999 | 10512535 |
| the influence of axial ligands on the reduction potential of blue copper proteins. | the reduction potentials of blue copper sites vary between 180 and about 1000 mv. it has been suggested that the reason for this variation is that the proteins constrain the distance between the copper ion and its axial ligands to different values. we have tested this suggestion by performing density functional b3lyp calculations on realistic models of the blue copper proteins, including solvent effects by the polarizable continuum method. constraining the cu-s(met) bond length to values between ... | 1999 | 10550695 |
| paramagnetic nmr investigations of co(ii) and ni(ii) amicyanin. | the paramagnetic 1h nmr spectra of the co(ii) and ni(ii) substituted forms of the type 1 blue copper protein (cupredoxin) amicyanin have been assigned. this is the first such analysis of a cupredoxin, which has a distorted tetrahedral active site with the ligands provided by two histidines, a cysteine and a methionine. the isotropic shifts of the resonances in these spectra are compared with those of co(ii) and ni(ii) azurin. a number of interesting similarities and differences are found. the co ... | 1999 | 10555580 |
| [sensitivity of soil bacteria isolated from the alienated zone around the chernobyl nuclear power plant to various stress factors]. | seventy strains of chemoorganotrophic bacteria isolated by our group in 1993-1994 from soil sampled in the zone around the chernobyl nuclear power plant (chnpp) were studied with respect to their sensitivity to various stress factors damaging dna. bacillus subtilis, b. cereus (both spores and vegetative cells), methylobacterium extorquens, m. mesophilicum, and unidentified pigmented bacteria were found to be the most resistant to ultraviolet (uv) radiation, exhibiting ld90 values of 40 to more t ... | 1999 | 10576090 |
| microbial metabolism of methanesulfonic acid | methanesulfonic acid is a very stable strong acid and a key intermediate in the biogeochemical cycling of sulfur. it is formed in megatonne quantities in the atmosphere from the chemical oxidation of atmospheric dimethyl sulfide (most of which is of biogenic origin) and deposited on the earth in rain and snow, and by dry deposition. methanesulfonate is used by diverse aerobic bacteria as a source of sulfur for growth, but is not known to be used by anaerobes either as a sulfur source, a fermenta ... | 1999 | 10591843 |
| spectroscopic and electrochemical properties of two azurins (az-iso1 and az-iso2) from the obligate methylotroph methylomonas sp. strain j and the structure of novel az-iso2. | two azurin-type blue copper proteins, which are related to the electron-transfer processes involving methylamine/methanol oxidation, have been spectroscopically and electrochemically characterized. the obligate methylotroph methylomonas sp. strain j gives rise to two azurins (az-isol and az-iso2) with methylamine dehydrogenase (madh-mj). the intense blue bands characteristic of az-iso1 and az-iso2 are observed at 621 and 616 nm in the visible absorption spectra respectively, being revealed at 62 ... | 1999 | 10631606 |
| culture-dependent and culture-independent characterization of microbial assemblages associated with high-temperature petroleum reservoirs. | recent investigations of oil reservoirs in a variety of locales have indicated that these habitats may harbor active thermophilic prokaryotic assemblages. in this study, we used both molecular and culture-based methods to characterize prokaryotic consortia associated with high-temperature, sulfur-rich oil reservoirs in california. enrichment cultures designed for anaerobic thermophiles, both autotrophic and heterotrophic, were successful at temperatures ranging from 60 to 90 degrees c. heterotro ... | 2000 | 10653739 |
| analysis of two formaldehyde oxidation pathways in methylobacillus flagellatus kt, a ribulose monophosphate cycle methylotroph. | the roles of cyclic formaldehyde oxidation via 6-phosphogluconate dehydrogenase and linear oxidation via the tetrahydromethanopterin (h4mpt)-linked pathway were assessed in an obligate methylotroph, methylobacillus flagellatus kt, by cloning, sequencing and mutating two chromosomal regions containing genes encoding enzymes specifically involved in these pathways: 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase and methenyl h4mpt cyclohydrolase (gnda, zwf and mch). no null mut ... | 2000 | 10658669 |
| tyr(30) of amicyanin is not critical for electron transfer to cytochrome c-551i: implications for predicting electron transfer pathways. | a pathways analysis of the methylamine dehydrogenase-amicyanin-cytochrome c-551i protein electron transfer (et) complex predicts two sets of et pathways of comparable efficiency from the type i copper of amicyanin to the heme of cytochrome c-551i. in one pathway, the electron exits copper via the cys(92) copper ligand, and in the other, it exits via the met(98) copper ligand. if the pathways algorithm is modified to include contributions from the anisotropy of metal-ligand coupling, independent ... | 2000 | 10692547 |
| structure, function, and applications of tryptophan tryptophylquinone enzymes. | tryptophan and tyrosine residues in proteins may be posttranslationally modified to form enzyme cofactors. tryptophan tryptophylquinone (ttq), the cofactor of methylamine dehydrogenase (madh), is formed by covalent cross-linking of two tryptophan residues and incorporation of two oxygen atoms into one of the indole rings to form a quinone. madh converts primary amines to their corresponding aldehydes plus ammonia. during the catalytic cycle, ttq mediates electron transfer from substrate to a cop ... | 1999 | 10721104 |
| x-ray structure of the quinoprotein ethanol dehydrogenase from pseudomonas aeruginosa: basis of substrate specificity. | the homodimeric enzyme form of quinoprotein ethanol dehydrogenase from pseudomonas aeruginosa atcc 17933 crystallizes readily with the space group r3. the x-ray structure was solved at 2.6 a resolution by molecular replacement. aside from differences in some loops, the folding of the enzyme is very similar to the large subunit of the quinoprotein methanol dehydrogenases from methylobacterium extorquens or methylophilus w3a1. eight w-shaped beta-sheet motifs are arranged circularly in a propeller ... | 2000 | 10736230 |
| electronic structure contributions to electron transfer in blue cu and cu(a). | the experimentally determined electronic structures of mononuclear blue cu and binuclear cu(a) centers are summarized and their relation to intra- and inter-protein electron transfer (et) kinetics are described. specific contributions of the electronic structures of these two broad classes of cu et proteins to h(ab), lambda, and deltae degrees are discussed. also, the role of the protein structure in determining key geometric features which define the electronic structures of the metal sites in ... | 2000 | 10766432 |
| 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 |
| isolation and characterization of two new methanesulfonic acid-degrading bacterial isolates from a portuguese soil sample. | two novel bacterial strains that can utilize methanesulfonic acid as a source of carbon and energy were isolated from a soil sample collected in northern portugal. morphological, physiological, biochemical and molecular biological characterization of the two isolates indicate that strain p1 is a pink-pigmented facultative methylotroph belonging to the genus methylobacterium, while strain p2 is a restricted methylotroph belonging to the genus hyphomicrobium. both strains are strictly aerobic, deg ... | 2000 | 10795686 |
| detection and classification of atmospheric methane oxidizing bacteria in soil. | well-drained non-agricultural soils mediate the oxidation of methane directly from the atmosphere, contributing 5 to 10% towards the global methane sink. studies of methane oxidation kinetics in soil infer the activity of two methanotrophic populations: one that is only active at high methane concentrations (low affinity) and another that tolerates atmospheric levels of methane (high affinity). the activity of the latter has not been demonstrated by cultured laboratory strains of methanotrophs, ... | 2000 | 10821271 |
| characterization of a second methylene tetrahydromethanopterin dehydrogenase from methylobacterium extorquens am1. | cell extracts of methylobacterium extorquens am1 were recently found to catalyze the dehydrogenation of methylene tetrahydromethanopterin (methylene h4mpt) with nad+ and nadp+. the purification of a 32-kda nadp-specific methylene h4mpt dehydrogenase (mtda) was described already. here we report on the characterization of a second methylene h4mpt dehydrogenase (mtdb) from this aerobic alpha-proteobacterium. purified mtdb with an apparent molecular mass of 32 kda was shown to catalyze the oxidation ... | 2000 | 10848995 |
| detection of intracellular bacteria in the buds of scotch pine (pinus sylvestris l.) by in situ hybridization. | bacterial isolates were obtained from pine (pinus sylvestris l.) tissue cultures and identified as methylobacterium extorquens and pseudomonas synxantha. the existence of bacteria in pine buds was investigated by 16s rrna in situ hybridization. bacteria inhabited the buds of every tree examined, primarily colonizing the cells of scale primordia and resin ducts. | 2000 | 10877808 |
| methylobacterium mesophilicum infection: case report and literature review of an unusual opportunistic pathogen. | methylobacterium mesophilicum is a methylotrophic, pink pigmented, gram-negative rod that was initially isolated from environmental sources that is being increasingly reported as a cause of opportunistic infections in immunocompromised hosts. we present the case of an immunocompromised woman who developed a central catheter infection with m. mesophilicum and review the other 29 cases reported in the literature, noting that it is frequently resistant to beta-lactam agents but is generally suscept ... | 2000 | 10880304 |
| diversity of culturable heterotrophic aerobic bacteria in pristine stream bed sediments. | more than 900 culturable, heterotrophic aerobic isolates were obtained from the sediments of a forested, pristine stream and analyzed using three classical microbiological tests: api 20e, amplified ribosomal dna restriction analysis (ardra), and fatty acid analysis. gram-negative bacteria comprised most of the heterotrophic aerobic isolates (66.7%), similar to other oligotrophic environments. the isolates were assigned to the genus level as pseudomonas, flavobacterium, micrococcus, bacillus, chr ... | 1999 | 10907425 |
| molecular basis for complex formation between methylamine dehydrogenase and amicyanin revealed by inverse mutagenesis of an interprotein salt bridge. | methylamine dehydrogenase (madh) and amicyanin form a physiologic complex which is required for interprotein electron transfer. the crystal structure of this protein complex is known, and the importance of certain residues on amicyanin in its interaction with madh has been demonstrated by site-directed mutagenesis. in this study, site-directed mutagenesis of madh, kinetic data, and thermodynamic analysis are used to probe the molecular basis for stabilization of the protein complex by an interpr ... | 2000 | 10913294 |
| volatile organic compounds associated with microbial growth in automobile air conditioning systems. | volatile organic compounds from penicillium viridicatum and methylobacterium mesophilicum growing on laboratory media and on component materials of automobile air conditioners were analyzed with gas chromatography and mass spectrometry. p. viridicatum produced compounds such as 4-methyl thiazole, terpenes and alcohols, whereas m. mesophilicum produced dimethyl disulfide, dimethyl trisulfide, and chlorophenol with growth on laboratory media. in comparison with laboratory media, fewer volatiles we ... | 2000 | 10915209 |