| thermothrix thioparus gen. et sp. nov. a facultatively anaerobic facultative chemolithotroph living at neutral ph and high temperature. | thermothrix thioparus gen. et ep. nov. occurs naturally in a new mexico hot spring at a temperature of 74 degrees c, a ph of 7.0, and a hs- concentration of 1 mg/litre. the organism is gram-negative, non-motile, 0.5-1.0 x 3-20 mum, and forms cell chains up to 1 cm in length. the resulting filaments do not possess a sheath. sulfur is deposited extracellularly. the organism was isolated using an autotrophic medium with hs- as the energy source and no3- as the terminal electron acceptor. anaerobica ... | 1976 | 10063 |
| role of low-molecular weight factors isolated from methanobacillus kuzneceovii in the activating effect of visible light on methane formation and reduction of pyridine nucleotides. | four low molecular weight fluorescent factors are isolated from thermophylic methaneproducing facteria methanobacterium kuzneceovii. these factors are: the factor 340; the factor 420 (both reduced and oxidized); and a flavine derivative, comprising together with proteins a biochemical system, which reduces pyridine nucleotides in dark (at 55degrees c) and in the light (at 21degrees c). | 1977 | 16669 |
| carbon monoxide oxidation by methanogenic bacteria. | different species of methanogenic bacteria growing on co(2) and h(2) were shown to remove co added to the gas phase. rates up to 0.2 mumol of co depleted/min per 10 ml of culture containing approximately 7 mg of cells (wet weight) were observed. methanobacterium thermoautotrophicum was selected for further study based on its ability to grow rapidly on a completely mineral medium. this species used co as the sole energy source by disproportionating co to co(2) and ch(4) according to the following ... | 1977 | 21159 |
| atp activation and properties of the methyl coenzyme m reductase system in methanobacterium thermoautotrophicum. | the requirement of atp for the methyl coenzyme m methylreductase in extracts of methanobacterium thermoautotrophicum was found to be catalytic; for each mol of atp added, 15 mol of methane was produced from methyl coenzyme m 2-(methylthio)ethanesulfonic acid. other nucleotide triphosphates partially replaced atp in activation of the reductase. all components of the reaction were found in the supernatant fraction of cell extracts after centrifugation at 100,000 x g for 1 h; optimal reaction rates ... | 1978 | 29032 |
| evidence for an incomplete reductive carboxylic acid cycle in methanobacterium thermoautotrophicum. | the involvement of reactions of the tricarboxylic acid cycle in autotrophic co2 fixation in methanobacterium thermoautotrophicum was investigated. the incorporation of succinate into glutamate (= alpha-ketoglutarate), aspartate (= oxaloacetate) and alanine (= pyruvate) was studied. the organism was grown on h2 plus co2 at ph 6.5 in the presence of 1 mm u-14c-succinate. significant amounts of the dicarboxylic acid were incorporated into cellular material under these conditions. alanine, aspartate ... | 1978 | 29586 |
| atp hydrolysis and synthesis by the membrane-bound atp synthetase complex of methanobacterium thermoautotrophicum. | the membrane-bound atp synthetase complex of methanobacterium thermoautotrophicum showed maximum activity for atp hydrolysis at ph 8, at temperatures between 65 and 70 degrees c, and at an atp-mg2+ ratio of 0.5. anaerobic conditions were not prerequisite for enzyme activity. the enzyme showed a km value for atp of 2 mm, and activity was mg2+ dependent; mn2+, co2+, ca2+, and zn2+ could replace mg2+ to some extent. other nucleoside triphosphates could be hydrolyzed. n,n'-dicyclohexylcarbodiimide i ... | 1978 | 30747 |
| transport of coenzyme m (2-mercaptoethanesulfonic acid) in methanobacterium ruminantium. | a system for transport of coenzyme m, 2-mercaptoethanesulfonic acid (hs--com), in methanobacterium ruminatium strain m1 required energy, showed saturation kinetics, and concentrated the coenzyme against a gradient. the process was sensitive to temperature and was maximally active at ph 7.1. cells took up hs--com at a linear rate, with a vmax of 312 pmol/min per mg (dry weight) and an apparent km of 73 nm. an intracellular pool of up to 5 mm accumulated which was not exchangeable with the medium. ... | 1979 | 33148 |
| solubilization and properties of a particulate hydrogenase from methanobacterium strain g2r. | mechanical disruption of cells of methanobacterium strain g2r resulted in a 78-fold increase in the specific activity of the hydrogenase as measured by the benzyl viologen reduction assay. approximately 50% of the activity in disrupted cells was associated with the particulate fraction. between 69 and 85% of the particulate hydrogenase was released by treatment with the detergents triton x-100, deoxycholate, and octyl-beta-d-glucopyranoside. the relative electrophoretic mobilities of the soluble ... | 1979 | 37236 |
| distribution of coenzyme f420 and properties of its hydrolytic fragments. | the ability of hydrolytic products of coenzyme f420 to substitute for f420 in the hydrogenase and nicotinamide adenine dinucleotide phosphate-liniked hydrogenase systems of methanobacterium strain m.o.h. was kinetically determined. the nicotinamide adenine dinucleotide phosphate-linked hydrogenase system was employed to quantitate the levels of f420 in a number of methanogenic bacteria as well as in some nonmethanogens. methanobacterium ruminantium and methanosarcina barkeri contained low levels ... | 1979 | 40952 |
| preparation of coenzyme m analogues and their activity in the methyl coenzyme m reductase system of methanobacterium thermoautotrophicum. | a number of 2-(methylthio)ethanesulfonate (methyl-coenzyme m) analogues were synthesized and investigated as substrates for methyl-coenzyme m reductase, an enzyme system found in extracts of methanobacterterium thermoautotrophicum. replacement of the methyl moiety by an ethyl group yielded an analogue which served as a precursor for ethane formation. propyl-coenzyme m, however, was not converted to propane. analogues which contained additional methylene carbons such as 3-(methylthio)propanesulfo ... | 1978 | 98178 |
| one-carbon metabolism in methanogenic bacteria: analysis of short-term fixation products of 14co2 and 14ch3oh incorporated into whole cells. | methanobacterium thermoautotrophicum, m. ruminantium, and methanosarcina barkeri were labeled with 14co2 (14co2 + h14co3- + 14co32-) for from 2 to 45 s. radioactivity was recovered in coenzyme m derivatives, alanine, aspartate, glutamate, and several unidentified compounds. the properties of one important structurally unidentified intermediate (yellow fluorescent compound) displayed uv absorbance maxima at ph 1 of 290 and 335 nm, no absorbance in the visible region, and a fluorescence maximum at ... | 1978 | 101522 |
| specificity and biological distribution of coenzyme m (2-mercaptoethanesulfonic acid). | the specificity of the growth requirement of methanobacterium ruminantium strain m1 for a new coenzyme, 2-mercaptoethanesulfonic acid (hs--com), was examined. a variety of derivatives, analogs, and potential biosynthetic precursors of coenzyme m were tested; only a restricted range of thioether, thioester, and thiocarbonate derivatives of the cofactor were found to replace the hs--com requirement. bromoethanesulfonic acid (brch2ch2so3-), a halogenated analog of hs--com, potently inhibited the gr ... | 1979 | 104960 |
| nickel, cobalt, and molybdenum requirement for growth of methanobacterium thermoautotrophicum. | growth of methanobacterium thermoautotrophicum on h2 and co2 as sole energy and carbon sources was found to be dependent on ni, co, and mo. at low concentrations of ni (less than 100 nm), co (less than 10 nm) and mo (less than 10 nm) the amount of cells formed was roughly proportional to the amount of transition metal added to the medium; for the formation of 1 g cells (dry weight) approximately 150 nmol nicl2, 20 nmol cocl2 and 20 nmol na2moo4 were required. a dependence of growth on cu, mn, zn ... | 1979 | 120728 |
| chemiosmotic coupling in methanobacterium thermoautotrophicum: hydrogen-dependent adenosine 5'-triphosphate synthesis by subcellular particles. | hydrogenase and the adenosine 5'-triphosphate (atp) synthetase complex, two enzymes essential in atp generation in methanobacterium thermoautotrophicum, were localized in internal membrane systems as shown by cytochemical techniques. membrane vesicles from this organism possessed hydrogenase and adenosine triphosphatase (atpase) activity and synthesized atp driven by hydrogen oxidation or a potassium gradient. atp synthesis depended on anaerobic conditions and could be inhibited in membrane vesi ... | 1979 | 160408 |
| amorphous ferrous sulfide as a reducing agent for culture of anaerobes. | amorphous ferrous sulfide, prepared by reacting ferrous ammonium sulfate and sodium sulfide, is an excellent reducing agent for the culture of anaerobes. it reduces resazurin and reacts much more rapidly with o2 than does either soluble sulfide (hs)- or cysteine. one of the end products of the oxidation of ferrous sulfide with o2 is red and serves as an indicator for the oxygen contamination of a culture medium. amorphous ferrous sulfide served as a suitable reducing agent for the growth of spec ... | 1977 | 192144 |
| factor 420-dependent pyridine nucleotide-linked hydrogenase system of methanobacterium ruminantium. | methanobacterium ruminantium was shown to possess a nicotinamide adenine dinucleotide phosphate (nadp)-linked factor 420 (f420)-dependent hydrogenase system. this system was also shown to be present in methanobacterium strain moh. the hydrogenase system of m. ruminantium also links directly to f420, flavin adenine dinucleotide (fad), flavin mononucleotide (fmn), methyl viologen, and fe-3 plus. it has a ph optimum of about 8 and an apparent km for f420 of about 5 x 10-6 m at ph 8 when nadp is the ... | 1975 | 234934 |
| factor 420-dependent pyridine nucleotide-linked formate metabolism of methanobacterium ruminantium. | methanobacterium ruminantium was shown to possess a formate dehydrogenase which is linked to factor 420 (f420) as the first low-molecular-weight or anionic electron transfer coenzyme. reduced f420 obtained from the formate dehydrogenase can be further linked to the formation of hydrogen via the previously described f420-dependent hydrogenase reaction, thus constituting an apparently simple formate hydrogenlyase system, or to the reduction of nicotinamide adenine dinucleotide phosphate via f420:n ... | 1975 | 234935 |
| application of the fluorescent-antibody technique to the study of a methanogenic bacterium in lake sediments. | fluorescent antibody (fa) was prepared for a methanogenic bacterium isolated from wintergreen lake pelagic sediment. the isolate resembles methanobacterium formicicum. the fa did not cross-react with 9 other methanogens, including m. formicicum strains, or 24 heterotrophs, 18 of which had been isolated from wintergreen lake sediment. fa-reacting methanogens were detected in heat-fixed smears of several different lake sediments and anaerobic sewage sludge. pretreatment of all samples with either ... | 1978 | 341807 |
| dna organization of methanobacterium thermoautotrophicum. | the organism methanobacterium thermoautotrophicum, an archaebacterium, is envolutionarily very distant from both traditional prokaryotes and eukaryotes. its genome (dna) has physical characteristics typical of most prokaryotes except that it is quite small (about 10(9) daltons, less than half the size of the genome of escherichia coli) and contains a significant amount (6 percent) dna which renatures extremely rapidly. | 1979 | 377486 |
| an ancient divergence among the bacteria. | the 16s ribosomal rnas from two species of methanogenic bacteria, the mesophile methanobacterium ruminantium and the thermophile methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with t1 ribonuclease. these two organisms are found to be sufficiently related that they can be considered members of the same genus or family. however, they bear only slight resemblance to "typical" procaryotic genera; such as escherichia, bacillus and ... | 1977 | 408502 |
| stimulation of co2 reduction to methane by methylcoenzyme m in extracts methanobacterium. | | 1977 | 409394 |
| nutritional and biochemical characterization of methanospirillum hungatii. | to ascertain its physiological similarity to other methanogenic bacteria, methanospirillum hungatii, the type species of the genus, was characterized nutritionally and biochemically. good growth occurred in a medium consisting of mineral salts, cysteine sulfide reducing buffer, and an h2-co2 (80:20) atmosphere. addition of amino acids and b vitamins stimulated growth. cell-free extracts contained methylcobalamin-coenzyme m methyltransferase, methylreductase, and formate hydrogenlyase. cells cont ... | 1977 | 411420 |
| influence of sulfide compounds on the metabolism of methanobacterium strain az. | various organic sulfides and inorganic sulfide were studied in respect to their effect on growth and methane production of methanobacterium strain az. in mineral, sulfide-free medium, cysteine regulated the specific rate of methane production (optimum concentration = 5-10(-4) mole/1). a supplement of sulfide (10(-4) mole/1) caused an additional stimulation. coenzyme m** or glutathione could be substituted for cysteine when sulfide was present. growth was stimulated by com and glutathione to the ... | 1977 | 412476 |
| coenzyme m and methylcobalamin in methane biosynthesis: results of model studies. | coenzyme m (2-mercaptoethanesulfonate, hs-ch2ch2so3-) reacts with methylcobalamin nonenzymatically in the ph-range between 6 and 14 to yield the s-methyl derivative (ch3-s-ch2ch2so3-). in addition, and also at lower ph, methane is produced by reductive cleavage of the co-c bond. with methylcobaloximes as the methyl group donors, methane production predominates, with insignificant s-methylation. the initial rates of methane production from methylcobaloximes with coenzyme m as the reductant correl ... | 1978 | 414787 |
| methane synthesis without the addition of adenosine triphosphate by cell membranes isolated from methanobacterium ruminantium. | the membrane fraction isolated from broken cells of methanobacterium ruminantium actively synthesized methane from co2 and h2 without the addition of atp or other cofactors. this activity was lost unless strictly anaerobic conditions were maintained throughout the isolation and incubation procedures. 3h2, but not 3h2o, was readily incorporated into methane. this indicates that hydrogen atoms are used in the formation of methane without the prior equilibration of protons with the water phase. met ... | 1979 | 435275 |
| the amino acid sequence of the peptide moiety of the pseudomurein from methanobacterium thermoautotrophicum. | the amino acid sequence of the peptide subunits of the peptide moiety of the sacculus polymer (pseudomurein) of methanobacterium thermoautotrophicum was elucidated by analysing overlapping peptides obtained from partial acid hydrolsates of isolated sacculi. it is suggested that the peptide subunits are attached to glycan strands via one of their glutamyl residues. another glutamyl residue may crosslink two adjacent peptide subunits to form a dimer. the calculated molar ratios of the amino acids ... | 1979 | 518234 |
| fermentation of cellulose by ruminococcus flavefaciens in the presence and absence of methanobacterium ruminantium. | the anaerobic cellulolytic rumen bacterium ruminococcus flavefaciens normally produces succinic acid as a major fermentation product together with acetic and formic acids, h2, and co2. when grown on cellulose and in the presence of the methanogenic rumen bacterium methanobacterium ruminantium, acetate was the major fermentation product; succinate was formed in small amounts; little formate was detected; h2 did not accumulate; and large amounts of ch4 were formed. m. ruminantium depends for growt ... | 1977 | 562131 |
| influence of ch4 production by methanobacterium ruminantium on the fermentation of glucose and lactate by selenomonas ruminantium. | a method is described for increasing the production of h2 from glucose or lactate by selenomonas ruminantium by sequential transfers in media containing pregrown methanobacterium ruminantium. the methanogen uses the h2 formed by the selenomonad to reduce co2 to ch4. analysis of fermentation products from glucose showed that lactate was the major product formed from glucose by s. ruminantium alone. several sequential transfers in the presence of the methanogen caused a marked decrease in lactate ... | 1977 | 596874 |
| acetate assimilation and the synthesis of alanine, aspartate and glutamate in methanobacterium thermoautotrophicum. | cultures of the autotrophic bacterium methanobacterium thermoautotrophicum were shown to assimilate acetate when grown on co2 and h2 in the presence of acetate. at 1 mm acetate 10% of the cell carbon came from acetate, the rest from co2. at higher concentrations the percentage increased to reach a maximum of 65% at acetate concentrations higher than 20 mm. the data suggest that acetate may be an important carbon source under physiological conditions. the incorporation of acetate into alanine, as ... | 1978 | 678012 |
| acetic acid and hydrogen metabolism during coculture of an acetic acid producing bacterium with methanogenic bacteria. | two microorganisms originally existing as a mixed culture obtained from an anaerobic digester fluid were separated for pure and coculture studies. one of these was motile, gram-negative, and non-sporeforming, and it required yeast extract for growth and acetic acid production. this isolate produced h2 and did not need h2 and (or) co2 for growth and acetate formation. the other isolate was a methanogen whick resembled methanobacterium arbophilicum in morphology and substrate specificity. cocultur ... | 1978 | 688097 |
| phytanyl-glycerol ethers and squalenes in the archaebacterium methanobacterium thermoautotrophicum. | | 1978 | 691077 |
| chemical composition of the peptidoglycan-free cell walls of methanogenic bacteria. | cell walls were prepared from freeze-dried samples of 7 strains of methanobacterium by mechanical disintegration of the cells followed by incubation with trypsin. electron microscopy revealed the presence of sacculi exhibiting the shape of the original cells, on which no surface structure could be detected. ultrathin sections of the isolated sacculi showed a homogenously electron dense layer of about 10--15 nm in width. the ash content varied between 8 and 18% of dry weight. the sacculi of all t ... | 1978 | 697504 |
| function of fumarate reductase in methanogenic bacteria (methanobacterium). | | 1978 | 727856 |
| proposed structure for coenzyme f420 from methanobacterium. | the low-potential electron carrier, coenzyme f420, was purified from methanobacterium strain m.o.h. a yield of 160 mg/kg of wet-packed cells was obtained. results of analysis of hydrolytic fragments and periodate oxidation products of the coenzyme, by infrared, uv-visible, 1h and 13cnmr spectrometry, mass spectrometry, and quantitative elemental analyses indicate that coenzyme f420 is: n-[n-[o-[5-(8-hydroxy-5-deazaisoalloxazin-10-yl)-2,3,4-trihydroxy-4-pentoxyhydroxyphosphinyl]-l-lactyl]-gamma-l ... | 1978 | 728375 |
| diphytanyl and dibiphytanyl glycerol ether lipids of methanogenic archaebacteria. | the lipids of nine different methanogenic bacterial strains are comprised of diphytanyl glycerol diethers, previously known only in extremely halophilic bacterial, as well as dibiphytanyl diglycerol tetraethers, known formerly only in the extremely thermoacidophilic bacteria thermoplasma and sulfolobus. of the methanogens examined from four representative taxonomic groups, methanobacterium and methanospirillum contained both types of isopranyl ethers in nearly equal proportions, whereas the cocc ... | 1979 | 758677 |
| acetate assimilation pathway of methanosarcina barkeri. | the pathway of acetate assimilation in methanosarcina barkeri was determined from analysis of the position of label in alanine, aspartate, and glutamate formed in cells grown in the presence of [14c]acetate and by measurement of enzyme activities in cell extracts. the specific radioactivity of glutamate from cells grown on [1-14c]- or [2-14c]acetate was approximately twice that of aspartate. the methyl and carboxyl carbons of acetate were incorporated into aspartate and glutamate to similar exte ... | 1979 | 762016 |
| methane formation and methane oxidation by methanogenic bacteria. | methanogenic bacteria were found to form and oxidize methane at the same time. as compared to the quantity of methane formed, the amount of methane simultaneously oxidized varied between 0.3 and 0.001%, depending on the strain used. all the nine tested strains of methane producers (methanobacterium ruminantium, methanobacterium strain m.o.h., m. formicicum, m. thermoautotrophicum, m. arbophilicum, methanobacterium strain az, methanosarcina barkeri, methanospirillum hungatii, and the "acetate org ... | 1979 | 762019 |
| inhibitory effects of h2 on growth of clostridium cellobioparum. | hydrogen inhibits the growth of hydrogen-producing clostridium cellobioparum, but not of escherichia coli or bacteroides ruminicola. the inhibition is reversible. when hydrogen was removed either by palladium black or by gassing out the tube, glucose utilization increased as did optical density and hydrogen production of c. cellobioparum. removal of the h2 by methanogenic bacteria favors the growth of c. cellobioparum. grown with methanobacterium ruminantium in various concentrations of glucose, ... | 1976 | 779644 |
| new method for the isolation and identification of methanogenic bacteria. | a new technique is reported for the rapid growth and detection of methanogenic bacteria by using petri plates. the method employs an anaerobic glove box containing an inner chamber with separate gas-flushing facilities. the numbers of methanogenic bacteria recovered from domestic sewage sludge are comparable to those recovered by other methods. the methanogenic organisms isolated from sludge include methanosarcina, methanospirillum, methanobacterium strain m.o.h., and methanobacterium formicicum ... | 1975 | 804855 |
| temperature limitation of methanogenesis in aquatic sediments. | microbial methanogenesis was examined in sediments collected from lake mendota, wisconsin, at water depths of 5, 10, and 18 m. the rate of sediment methanogenesis was shown to vary with respect to sediment site and depth, sampling date, in situ temperature, and number of methanogens. increased numbers of methanogenic bacteria and rates of methanogenesis correlated with increased sediment temperature during seasonal change. the greatest methanogenic activity was observed for 18-m sediments throug ... | 1976 | 821396 |
| new approach to the cultivation of methanogenic bacteria: 2-mercaptoethanesulfonic acid (hs-com)-dependent growth of methanobacterium ruminantium in a pressureized atmosphere. | the sensitivity of the requirement of methanobacterium ruminantium strain m1 to a new coenzyme, 2-mercaptoethanesulfonic acid (hs-com) was examined by use of new techniques that were developed for rapid and efficient handling of large numbers of cultures of methanogenic bacteria. the system uses sealed tubes that contain a gas mixture of 80% hydrogen and 20% carbon dioxide under a pressure of 2 to 3 atm. this modification of the hungate technique reduces variability among replicate cultures and ... | 1976 | 827241 |
| fermentation of cellulose and cellobiose by clostridium thermocellum in the absence of methanobacterium thermoautotrophicum. | the fermentation of cellulose and cellobiose by clostridium thermocellum monocultures and c. thermocellum/methanobacterium thermoautotrophicum cocultures was studied. all cultures were grown under anaerobic conditions in batch culture at 60 degrees c. when grown on cellulose, the coculture exhibited a shorter lag before initiation and growth and celluloysis than did the monoculture. cellulase activity appeared earlier in the coculture than in the monoculture; however, after growth had ceased, ce ... | 1977 | 848953 |
| growth of desulfovibrio in lactate or ethanol media low in sulfate in association with h2-utilizing methanogenic bacteria. | in the analysis of an ethanol-co(2) enrichment of bacteria from an anaerobic sewage digestor, a strain tentatively identified as desulfovibrio vulgaris and an h(2)-utilizing methanogen resembling methanobacterium formicicum were isolated, and they were shown to represent a synergistic association of two bacterial species similar to that previously found between s organism and methanobacterium strain moh isolated from methanobacillus omelianskii. in lowsulfate media, the desulfovibrio produced ac ... | 1977 | 879775 |
| effect of sodium chloride on growth and methane production of methanogens. | the effect of up to 263.7 mm sodium chloride on the growth and methane production by pure cultures of methanospirillum hungatii gp1, methanobacterium moh, methanobacterium thermoautotrophicum, and an unidentified methanogen was studied. growth and methane production by m. hungatii gp1 were not affected up to 97.3 mm nacl but there was some inhibition of growth at higher concentrations. growth of methanobacterium moh was independent of sodium chloride concentration within the range investigated. ... | 1977 | 884626 |
| nutrition and factors limiting the growth of a methanogenic bacterium (methanobacterium thermoautotrophicum). | the purification of methanobacterium thermoautotrophicum from a culture contaminated with a heterotrophic organism is described. a defined inorganic medium under h2/co2 (80:20 v/v) has been developed to support growth of m. thermoautotrophicum up to a concentration of at least 1.7 g dry weight/l. in a conventional medium iron and nitrogen sources were found to be growth-limiting factors. throughout most of the culture period the rate of transfer of hydrogen or carbon dioxide from gas to liquid w ... | 1977 | 889384 |
| oxidoreductases involved in cell carbon synthesis of methanobacterium thermoautotrophicum. | cell-free extracts of methanobacterium thermoautotrophicum were found to contain high activities of the following oxidoreductases (at 60 degrees c): pyruvate dehydrogenase (coenzyme a acetylating), 275 nmol/min per mg of protein; alpha-ketoglutarate dehydrogenase (coenzyme a acylating), 100 nmol/min per mg; fumarate reductase, 360 nmol/min per mg; malate dehydrogenase, 240 nmol/min per mg; and glyceraldehyde-3-phosphate dehydrogenase, 100 nmol/min per mg. the kinetic properties (apparent v(max) ... | 1977 | 914779 |
| inhibition of methanogenesis in salt marsh sediments and whole-cell suspensions of methanogenic bacteria by nitrogen oxides. | hydrogen-dependent evolution of methane from salt marsh sediments and whole-cell suspensions of methanobacterium thermoautotrophicum and methanobacterium fornicicum ceased or decreased after the introduction of nitrate, nitrite, nitric oxide, or nitrous oxide. sulfite had a similar effect on methanogenesis in the whole-cell suspensions. in salt marsh sediments, nitrous oxide was the strongest inhibitor, followed by nitric oxide, nitrite, and nitrate in decreasing order of inhibition. in whole-ce ... | 1976 | 970945 |
| methanobacterium arbophilicum sp.nov. an obligate anaerobe isolated from wetwood of living trees. | the isolation and characterization of a new methanogenic bacterium, methanobacterium arbophilicum, is described. isolation from wetwood enrichment cultures, that were obtained from methane-positive trees, required a medium containing inorganic salts, vitamins, and an atmosphere consisting of an 80:20 mixture of hydrogen-carbon dioxide. isolates of m. arbophilicum were gram-positive, non-motile short rods that occurred singly, in pairs, or chains. the organism was found to be an autotroph and a s ... | 1975 | 1083210 |
| methane fermentation of rubber (hevea brasiliensis) latex effluent. | four species of bacteria capable of ch4 fermentation of rubber latex effluent were isolated and identified as a methanococcus, a strain of m. vannielii, a methanobacterium and a strain of m. omelianskii. auxanographic tests using the four strains showed growth and ch4 formation on a basal medium containing mineral salts or added h2 and co2. varied response was obtained when the basal medium was added to formate, acetate, butyrate, methanol, ethanol, and glucose. previous work has established aci ... | 1976 | 1252994 |
| further studies on aspartate aminotransferase of thermophilic methanogens by analysis of general properties, bound cofactors, and subunit structures. | aspartate aminotransferase (aspat) [ec 2.6.1.1] of thermophilic methanogen was further characterized with the enzyme from methanobacterium thermoautotrophicum strain ftf-inra as well as m. thermoformicicum strain sf-4. aspat of strain ftf-inra was similar in the amino donor specificity to the enzyme of m. thermoformicicum strain sf-4, in that it was active on l-cysteine and l-cysteine sulfinate in addition to l-glutamate and l-aspartate. the enzymes gave similar absorption spectra having maxima ... | 1992 | 1295891 |
| on the redox equilibrium between h2 and hydrogenase. | redox titrations of the nickel ion in active hydrogenase from methanobacterium thermoautotrophicum and chromatium vinosum were performed in the absence of artificial redox mediators, by variation of the h2-partial pressure. these experiments revealed a redox behaviour of the nickel ion which differed remarkably from previous redox titrations in the presence of redox mediators. notably the epr signal of the species earlier characterized as monovalent nickel with bound hydrogen, behaved as an n = ... | 1992 | 1311607 |
| isolation and characterization of polyferredoxin from methanobacterium thermoautotrophicum. the mvhb gene product of the methylviologen-reducing hydrogenase operon. | the methylviologen-reducing hydrogenase operon of methanobacterium thermoautotrophicum contains an open reading frame, mvhb, the product of which was predicted to have a molecular weight of 44 kda and to contain as many as 48 iron atoms in 12 [4fe-4s] clusters, and was therefore suggested to be a polyferredoxin. we have now, for the first time, isolated this polyferredoxin. its identity with the mvhb gene product was evidenced by a comparison of the n-terminal amino acid sequence. the dark-brown ... | 1992 | 1312016 |
| spectroscopic characterization of the alternate form of s-methylcoenzyme m reductase from methanobacterium thermoautotrophicum (strain delta h). | two forms (mr1 and mr2) of s-methylcoenzyme m reductase were purified from methanobacterium thermoautotrophicum (strain delta h) as recently described (rospert, s., linder, d., ellerman, j. and thauer, r.k. (1990) eur. j. biochem. 194, 871-877). mr2 was at least 50-fold more active than mr1, independent of assay conditions. the two forms are spectroscopically similar, but not identical, by uv-visible, magnetic circular dichroism and resonance raman spectroscopies. mr2 exhibited an epr signal cor ... | 1992 | 1314088 |
| properties of the tungsten-substituted molybdenum formylmethanofuran dehydrogenase from methanobacterium wolfei. | in methanobacterium wolfei two formylmethanofuran dehydrogenases are present, one of which is a molybdenum- and the other a tungsten enzyme. we report here that also the 'molybdenum' enzyme contained tungsten when the archaeon was grown on molybdenum-deprived medium supplemented with tungstate (1 microm). unexpectedly the tungsten-substituted molybdenum enzyme was catalytically active and displayed a rhombic epr signal which was attributed to tungsten by the characteristic 183w splitting. | 1992 | 1324851 |
| a molybdenum and a tungsten isoenzyme of formylmethanofuran dehydrogenase in the thermophilic archaeon methanobacterium wolfei. | we have recently reported that the thermophilic archaeon methanobacterium wolfei contains two formylmethanofuran dehydrogenases, i and ii. formylmethanofuran dehydrogenase ii, which is preferentially expressed in tungsten-grown cells, has been purified and shown to be a tungsten-iron-sulfur protein. we have now purified and characterized formylmethanofuran dehydrogenase i from molybdenum-grown cells and shown that it is a molybdenum-iron-sulfur protein. the purified enzyme, with a specific activ ... | 1992 | 1330558 |
| substrate-analogue-induced changes in the nickel-epr spectrum of active methyl-coenzyme-m reductase from methanobacterium thermoautotrophicum. | methyl-coenzyme-m reductase (mcr) catalyzes the formation of methane from methyl-coenzyme m [2-(methylthio)ethanesulfonate] and 7-mercaptoheptanoylthreonine phosphate in methanogenic archaea. the enzyme contains the nickel porphinoid coenzyme f430 as a prosthetic group. in the active, reduced (red) state, the enzyme displays two characteristic epr signals, mcr-red1 and mcr-red2, probably derived from ni(i). in the presence of the substrate methyl-coenzyme m, the rhombic mcr-red2 signal is quanti ... | 1992 | 1332856 |
| modular organization of related archaeal plasmids encoding different restriction-modification systems in methanobacterium thermoformicicum. | nucleotide sequence comparison of the related 13513-bp plasmid pfv1 and the 11014-bp plasmid pfz1 from the thermophilic archaeon methanobacterium thermoformicicum thf and z-245, respectively, revealed a homologous, approximately 8.2 kb backbone structure that is interrupted by plasmid-specific elements. various highly conserved palindromic structures and an orf that could code for a ntp-binding protein were identified within the backbone structure and may be involved in plasmid maintenance and r ... | 1992 | 1336177 |
| streptomyces atp nucleotide 3'-pyrophosphokinase and its gene. | streptomyces atp nucleotide 3'-pyrophosphokinase is an extracellular, ribosome-independent, and stringent factor-mimic ppgpp synthetase with an unusually broad acceptor spectrum. the gene-containing dna fragments cloned from chromosomal dna of a producer s. morookaensis into pij699 and puc plasmids were found to express the active enzyme in the transformed s. lividans tk24 and enteric e. coli jm109 and nitrogen-fixing klebsiella pneumoniae m5a1 and 5022, respectively. base sequence of the struct ... | 1992 | 1337783 |
| biosynthetic precursors of deazaflavins. | the incorporation of 13c- and 14c-labeled precursors into 5-deaza-7,8-didemethyl-8-hydroxyriboflavin (factor f0) was studied with growing cells of methanobacterium thermoautotrophicum. 5-amino-6-ribitylamino-2,4(1h,3h)-pyrimidinedione was incorporated into the deazaflavin and into riboflavin without dilution. tyrosine and 4-hydroxyphenylpyruvate were incorporated into the deazaflavin and into cellular protein. 4-hydroxybenzaldehyde was not incorporated. a reaction mechanism is proposed for the f ... | 1992 | 1350778 |
| reductive dechlorination of 1,2-dichloroethane and chloroethane by cell suspensions of methanogenic bacteria. | concentrated cell suspensions of methanogenic bacteria reductively dechlorinated 1,2-dichloroethane via two reaction-mechanisms: a dihalo-elimination yielding ethylene and two hydrogenolysis reactions yielding chloroethane and ethane, consecutively. the transformation of chloroethane to ethane was inhibited by 1,2-dichloroethane. stimulation of methanogenesis caused an increase in the amount of dechlorination products formed, whereas the opposite was found when methane formation was inhibited. c ... | 1990 | 1368471 |
| identification of formate dehydrogenase-specific mrna species and nucleotide sequence of the fdhc gene of methanobacterium formicicum. | the overlapping fdha and fdhb genes of methanobacterium formicicum, which encode the alpha and beta subunits, respectively, of formate dehydrogenase, were cotranscribed as part of an approximately 4.5-kb transcript. an additional gene (fdhc) upstream of fdha was cotranscribed with fdha and fdhb. the deduced amino acid sequence suggested that fdhc has the potential to encode a hydrophobic polypeptide with a calculated molecular weight of 29,417. a hydropathy plot of the hypothetical polypeptide i ... | 1992 | 1378430 |
| dna relatedness among some thermophilic members of the genus methanobacterium: emendation of the species methanobacterium thermoautotrophicum and rejection of methanobacterium thermoformicicum as a synonym of methanobacterium thermoautotrophicum. | dna reassociation was used to determine levels of relatedness among four thermophilic methanobacterium strains that are able to use formate and between these organisms and two representative strains of methanobacterium thermoautotrophicum, strain delta ht (= dsm 1053t = atcc 29096t) (t = type strain) and strain marburg (= dsm 2133). three homology groups were delineated, and these groups coincided with the clusters identified by antigenic fingerprinting. the first group, which had levels of cros ... | 1992 | 1380288 |
| identification of the ctag-recognizing restriction-modification systems mthzi and mthfi from methanobacterium thermoformicicum and characterization of the plasmid-encoded mthzim gene. | two ctag-recognizing restriction and modification (r/m) systems, designated mthzi and mthfi, were identified in the thermophilic archaeon methanobacterium thermoformicicum strains z-245 and ftf, respectively. further analysis revealed that the methyltransferase (mtase) genes are plasmid-located in both strains. the plasmid pfz1-encoded mthzim gene of strain z-245 was further characterized by subcloning and expression studies in escherichia coli followed by nucleotide sequence analysis. the mthzi ... | 1992 | 1408820 |
| physical map of the methanobacterium thermoautotrophicum marburg chromosome. | a physical map of the methanobacterium thermoautotrophicum marburg chromosome was constructed by using pulsed-field gel electrophoresis of restriction fragments generated by noti, pmei, and nhei. the order of the fragments was deduced from southern blot hybridization of noti fragment probes to various restriction digests and from partial digests. the derived map is circular, and the genome size was estimated to be 1,623 kb. several cloned genes were hybridized to restriction fragments to locate ... | 1992 | 1429448 |
| n5-methyltetrahydromethanopterin: coenzyme m methyltransferase in methanogenic archaebacteria is a membrane protein. | an assay is described that allows the direct measurement of the enzyme activity catalyzing the transfer of the methyl group from n5-methyltetrahydromethanopterin (ch3-h4mpt) to coenzyme m (h-s-com) in methanogenic archaebacteria. with this method the topology, the partial purification, and the catalytic properties of the methyltransferase in methanol- and acetate-grown methanosarcina barkeri and in h2/co(2)-grown methanobacterium thermoautotrophicum were studied. the enzyme activity was found to ... | 1992 | 1444718 |
| biochemistry of methanogenesis. | | 1992 | 1445409 |
| hmt, a histone-related protein from methanobacterium thermoautotrophicum delta h. | hmt, a histone-related protein, has been isolated and characterized from methanobacterium thermoautotrophicum delta h. hmt preparations contain two polypeptides designated hmt1 and hmt2, encoded by the hmta and hmtb genes, respectively, that have been cloned, sequenced, and expressed in escherichia coli. hmt1 and hmt2 are predicted to contain 68 and 67 amino acid residues, respectively, and have calculated molecular masses of 7,275 and 7,141 da, respectively. aligning the amino acid sequences of ... | 1992 | 1459937 |
| structures of archaebacterial membrane lipids. | structural data on archaebacterial lipids is presented with emphasis on the ether lipids of the methanogens. these ether lipids normally account for 80-95% of the membrane lipids with the remaining 5-20% of neutral squalenes and other isoprenoids. genus-specific combinations of various lipid core structures found in methanogens include diether-tetraether, dietherhydroxydiether, or diether-macrocyclic diether-tetraether lipid moieties. some species have only the standard diether core lipid, but n ... | 1992 | 1459987 |
| determination of the relative configuration of 5,6,7,8-tetrahydromethanopterin by two-dimensional nmr spectroscopy. | the relative configuration of the pterin moiety of 5,6,7,8-tetrahydromethanopterin 1, a coenzyme isolated from methanogenic archaea, has been determined by two-dimensional nmr spectroscopy of n5,n10-methenyl-5,6,7,8-tetrahydromethanopterin 2 to be rel-(6r; 7s; 11r). the complete proton resonance assignment of the pterin moiety of n5,n10-methylene-5,6,7,8-tetrahydromethanopterin 3 is described including the relative stereospecific assignment of the c(14a) methylene protons. | 1992 | 1468581 |
| salt dependence, kinetic properties and catalytic mechanism of n-formylmethanofuran:tetrahydromethanopterin formyltransferase from the extreme thermophile methanopyrus kandleri. | n-formylmethanofuran(cho-mfr):tetrahydromethanopterin(h4mpt) formyltransferase (formyltransferase) from the extremely thermophilic methanopyrus kandleri was purified over 100-fold to apparent homogeneity with a 54% yield. the monomeric enzyme had an apparent molecular mass of 35 kda. the n-terminal amino acid sequence of the polypeptide was determined. the formyltransferase was found to be absolutely dependent on the presence of phosphate or sulfate salts for activity. the ability of salts to ac ... | 1992 | 1483480 |
| identification and isolation of the polyferredoxin from methanobacterium thermoautotrophicum strain delta h. | sequencing the genes encoding the methyl viologen-reducing hydrogenase, cloned from methanobacterium thermoautotrophicum strain delta h and methanothermus fervidus, revealed the presence of tightly linked genes, designated mvhb, which were predicted to encode proteins containing six tandemly arranged bacterial ferrodoxin-like domains. a lacz-mvhb gene fusion has been constructed and expressed in escherichia coli. rabbit antibodies raised against the fusion polypeptide purified from e. coli have ... | 1992 | 1495982 |
| characterization of the archaeal, plasmid-encoded type ii restriction-modification system mthti from methanobacterium thermoformicicum thf: homology to the bacterial ngopii system from neisseria gonorrhoeae. | a restriction-modification system, designated mthti, was localized on plasmid pfv1 from the thermophilic archaeon methanobacterium thermoformicicum thf. the mthti system is a new member of the family of ggcc-recognizing restriction-modification systems. functional expression of the archaeal mthti genes was obtained in escherichia coli. the mthtir and mthtim genes are 843 and 990 bp in size and code for proteins of 281 (32,102 da) and 330 (37,360 da) amino acids, respectively. the deduced amino a ... | 1992 | 1512204 |
| the use of rrna sequences and fluorescent probes to investigate the phylogenetic positions of the anaerobic ciliate metopus palaeformis and its archaeobacterial endosymbiont. | the polymerase chain reaction (pcr) was used to amplify small-subunit ribosomal dna from the anaerobic ciliated protozoon metopus palaeformis, and from its uncultured endosymbiotic bacteria. this was accomplished directly from total dna extracted from protozoa without prior isolation or enrichment for symbiont cells. the double-stranded amplification products were precipitated and directly sequenced using the linear pcr reaction. fluorescent oligonucleotide probes were designed and used in whole ... | 1992 | 1512578 |
| biosynthesis of methanofuran in methanobacterium thermoautotrophicum. | the 13c nmr signals of methanofuran were assigned by two-dimensional 1h and 13c nmr experiments. on this basis, the incorporation of 13c-labeled acetate and pyruvate into methanofuran by growing cells of methanobacterium thermoautotrophicum was analyzed by one- and two-dimensional 13c nmr experiments. the data were analyzed by a retrobiosynthetic approach based on a comparison of labeling patterns in a variety of metabolites. the data show that the furan ring is formed by condensation of two mol ... | 1992 | 1517208 |
| h2-forming methylenetetrahydromethanopterin dehydrogenase, a novel type of hydrogenase without iron-sulfur clusters in methanogenic archaea. | a novel hydrogenase has recently been found in methanogenic archaea. it catalyzes the reversible dehydrogenation of methylenetetrahydromethanopterin (ch2 = h4mpt) to methenyltetrahydromethanopterin (ch identical to h4mpt+) and h2 and was therefore named h2-forming methylenetetrahydromethanopterin dehydrogenase. the hydrogenase, which is composed of only one polypeptide with an apparent molecular mass of 43 kda, does not mediate the reduction of viologen dyes with either h2 or ch2 = h4mpt. we rep ... | 1992 | 1521540 |
| targeted insertion of selenocysteine into the alpha subunit of formate dehydrogenase from methanobacterium formicicum. | selenocysteine incorporation into proteins is directed by an opal (uga) codon and requires the existence of a stem-loop structure in the mrna flanking the uga at its 3' side. to analyze the sequence and secondary-structure requirements for uga decoding, we have introduced mutations into the fdha gene from methanobacterium formicicum, which codes for the alpha subunit of the f420-reducing formate dehydrogenase. the m. formicicum enzyme contains a cysteine residue at the position where the escheri ... | 1992 | 1531049 |
| dehalogenation of trichlorofluoromethane (cfc-11) by methanosarcina barkeri. | methanobacterium barkeri was found to catalyze the reductive dehalogenation of trichlorofluoromethane (cfc-11), also known as freon 11. products detected were chfcl2, ch2fcl, co and fluoride. | 1992 | 1537550 |
| distinct redox behaviour of prosthetic groups in ready and unready hydrogenase from chromatium vinosum. | the redox behaviour of the ni(iii)/ni(ii) transition in hydrogenase from chromatium vinosum is described and compared with the redox behaviour of the nickel ion in the f420-nonreducing hydrogenase from methanobacterium thermoautotrophicum. analogous to the situation in the oxidised hydrogenase of desulfovibrio gigas (fernandez, v.m., hatchikian, e.c., patil, d.s. and cammack, r. (1986) biochim. biophys. acta 883, 145-154), the c. vinosum enzyme can also exist in two forms: the 'unready' form (ep ... | 1992 | 1540647 |
| effect of coculture of anaerobic fungi isolated from ruminants and non-ruminants with methanogenic bacteria on cellulolytic and xylanolytic enzyme activities. | neocallimastix strain n1, an isolate from a ruminant (sheep), was cocultured with three methanobacterium formicicum strains, methanosarcina barkeri, and methanobrevibacter smithii. the coculture with methanobacterium formicicum strains resulted in the highest production of cellulolytic and xylanolytic enzymes. subsequently four anaerobic fungi, two neocallimastix strains (n1 and n2) from a ruminant and two piromyces species from non-ruminants (e2 and r1), were grown in coculture with methanobact ... | 1992 | 1550443 |
| enzymatic degradation of cyclic 2,3-diphosphoglycerate to 2,3-diphosphoglycerate in methanobacterium thermoautotrophicum. | 2,3-diphosphoglycerate (2,3-dpg) has been found to be the product of the enzymatic degradation of cyclic 2,3-diphosphoglycerate (cdpg) in the archaebacterium methanobacterium thermoautotrophicum delta h. although 2,3-dpg has not previously been detected as a major soluble component of m. thermoautotrophicum, large pools accumulated at an incubation temperature of 50 degrees c (below the optimum growth temperature of 62 degrees c). under these conditions, cellular activity was significantly decre ... | 1992 | 1550819 |
| effect of magnesium on methanogenic subpopulations in a thermophilic acetate-degrading granular consortium. | the effects of mg2+ on thermophilic (55 degrees c) granules grown on acetate in 0.2-liter upflow anaerobic sludge blanket reactors were studied. the methanogens in the granules were identified and counted by using antibody probes and the antigenic fingerprinting method. packets of large coccoidal cells antigenically related to methanosarcina thermophila tm-1 were scarce in the absence of mg2+ but increased with increasing mg2+ concentrations up to 30 mm; methanosarcina packets immunologically re ... | 1992 | 1575487 |
| a possible new class of ribonucleotide reductase from methanobacterium thermoautotrophicum. | the ribonucleotide reductase from the strictly anaerobic methanogen methanobacterium thermoautotrophicum has been partially purified by ion-exchange and gel-filtration chromatography. its molecular weight is estimated to be 100,000 by the latter step. unlike all previously studied ribonucleotide reductases, the enzyme does not employ dithiol compounds such as dithiothreitol as artificial electron donors in in vitro assays. inhibition of the enzyme by s-adenosylmethionine, oxygen, and azide furth ... | 1992 | 1575730 |
| inhibition of invasion of mcf-7/6 human breast carcinoma cells in vitro by methanobacterium thermoautotrophicum extract. | precultured embryonic chick heart fragments were confronted in vitro with various invasive tumor cell lines (mcf-7/6 human breast carcinoma variant, bw-o-lii mouse t-cell lymphoma cells and mo4 virally transformed fetal mouse carcass cells) and with a non-invasive cell line (mcf-7/az human breast carcinoma variant). confronting cultures were incubated in the presence of various methanogenic cofactors: methanobacterium thermoautotrophicum extract, coenzyme f420, fo (7,8-didemethyl-8-hydroxy-5-dea ... | 1992 | 1580570 |
| differential expression of the two methyl-coenzyme m reductases in methanobacterium thermoautotrophicum as determined immunochemically via isoenzyme-specific antisera. | methanobacterium thermoautotrophicum contains two isoenzymes of methyl-coenzyme m reductase (mcr), mcr i and mcr ii, which catalyze the methane-forming step and which together represent more than 10% of the cellular protein. we describe here the preparation of isoenzyme-specific antisera against the two mcr isoenzymes and their use in the quantitative immunochemical determination of the two isoenzymes in the methanogen. the relative and absolute cellular concentration of the two proteins is show ... | 1992 | 1587287 |
| the purification, characterization, and primary structure of a small redox protein from methanobacterium thermoautotrophicum, an archaebacterium. | a small redox-active protein has been purified to homogeneity from cell-free extracts of the strictly anaerobic thermophilic methanogen, methanobacterium thermoautotrophicum (strain marburg). the purification consisted of streptomycin sulfate and acid treatments and three chromatographic steps using sephadex g-75, mono q hr 10/10, and superose 12 hr 10/30 columns. when these procedures were carried out under strictly anaerobic conditions, approximately 3 mg of this protein could be isolated from ... | 1992 | 1587836 |
| methanococcus voltae harbors four gene clusters potentially encoding two [nife] and two [nifese] hydrogenases, each of the cofactor f420-reducing or f420-non-reducing types. | four gene clusters were identified in methanococcus voltae which probably all encode hydrogenases of the [nife] type. one of these contains four genes, including those for the three subunits of the known [nifese] hydrogenase capable of reducing the natural deazaflavin cofactor f420. in a second homologous cluster, the gene encoding the subunit corresponding to that which contains selenium in the known enzyme has a cysteine codon in the relevant position. in addition, two more gene clusters were ... | 1992 | 1603063 |
| 5-formyl-5,6,7,8-tetrahydromethanopterin is the intermediate in the process of methanogenesis in methanosarcina barkeri. | formylmethanofuran:tetrahydromethanopterin (h4mpt) formyltransferase and 5,10-methenyl-h4mpt cyclohydrolase purified from methanosarcina barkeri catalyze a formyl group transfer and the hydrolysis of the methenyl function, respectively. the results from uv spectroscopy and hplc analyses, and comparison with results obtained with the enzymes isolated from methanobacterium thermoautotrophicum showed 5-formyl-h4mpt to be the product of the formyltransferase and cyclohydrolase reactions in m. barker ... | 1992 | 1605834 |
| methyl-coenzyme m reductase of methanobacterium thermoautotrophicum delta h catalyzes the reductive dechlorination of 1,2-dichloroethane to ethylene and chloroethane. | reductive dechlorination of 1,2-dichloroethane (1,2-dca) to ethylene and chloroethane (ca) by crude cell extracts of methanobacterium thermoautotrophicum delta h with h2 as the electron donor was stimulated by mg-atp. the heterodisulfide of coenzyme m (com) and 7-mercaptoheptanoylthreonine phosphate together with mg-atp partially inhibited ethylene production but stimulated ca production compared mg-atp alone. the ph optimum for the dechlorination was 6.8 (at 60 degrees c). michaelis-menten kine ... | 1992 | 1624435 |
| a tungsten-containing active formylmethanofuran dehydrogenase in the thermophilic archaeon methanobacterium wolfei. | methanobacterium wolfei is a thermophilic methanogenic archaeon which requires tungsten or molybdenum for growth. we have found that the organism contains two formylmethanofuran dehydrogenases, one of which is a tungsten enzyme. indirect evidence indicates that the other formylmethanofuran dehydrogenase is a molybdenum enzyme. the tungsten enzyme was purified and characterized. the native enzyme had an apparent molecular mass of 130 kda. sds/page revealed a composition of three subunits of appar ... | 1992 | 1633810 |
| f390 synthetase and f390 hydrolase from methanobacterium thermoautotrophicum (strain delta h). | factor f390 is the 8-oh adenylated form of the deazaflavin coenzyme f420, which is a central electron carrier in methanogenic bacteria. the enzymes catalysing the formation of f390 from atp and f420 (f390 synthetase) and its hydrolysis into amp and f420 (f390 hydrolase) were isolated and partially purified from methanobacterium thermoautotrophicum. both enzymes were oxygen-stable. the f390 synthetase tended to coelute with coenzyme f420 reducing hydrogenase during all purification steps. the 30- ... | 1991 | 1647779 |
| ni(ii) and ni(i) forms of pentaalkylamide derivatives of cofactor f430 of methanobacterium thermoautotrophicum. | a series of pentaalkylamide forms of f430 and of its 12,13-diepimer have been generated and characterized. carbodiimide-assisted n-hydroxysulfosuccinimide activation of all five peripheral carboxylates of the f430 macrocycle allows nucleophilic attack by a number of primary amines (rnh2, r- = ch3-, ch3ch2-, cf3ch2-, ch3(ch2)3-) generating the pentaalkylamide derivatives. the identity of each derivative has been verified by fast-atom bombardment mass spectrometry (fab-ms). the solubility of these ... | 1991 | 1648401 |
| methyl-coenzyme m reductase preparations with high specific activity from h2-preincubated cells of methanobacterium thermoautotrophicum. | the study of the nickel enzyme methyl-coenzyme m reductase from methanogenic bacteria has been hampered until now by the fact that upon cell rupture the activity of the enzyme always dropped to at best only a few percent of its in vivo activity. we describe here that when methanobacterium thermoautotrophicum cells were preincubated with 100% h2 before disintegration methyl-coenzyme m reductase activity stayed high. the cell extracts with a specific activity of 2 u/mg protein exhibited two nickel ... | 1991 | 1657649 |
| single step purification of methylenetetrahydromethanopterin reductase from methanobacterium thermoautotrophicum by specific binding to blue sepharose cl-6b. | methylenetetrahydromethanopterin reductase from metanogenic archaebacteria catalyzes the reversible reduction of n5,n10-methylenetetrahydromethanopterin to n5-methyltetrahydromethanopterin with reduced coenzyme f420 as electron donor. the enzyme is involved in methane formation from co2 and in methanol disproportionation to co2 and ch4. we report here that the reductase from methanobacterium thermoautotrophicum specifically binds to blue sepharose cl-6b. binding was competitive with coenzyme f42 ... | 1990 | 1696553 |
| structural modifications and kinetic studies of the substrates involved in the final step of methane formation in methanobacterium thermoautotrophicum. | the 2-(methylthio)ethanesulfonic acid (ch3-s-com) reductase catalyzes the final methane-yielding reaction in fastidiously anaerobic methanogenic archaebacteria. this step involves the reductive demethylation of ch3-s-com with reducing equivalents from n-7-(mercaptoheptanoyl)-l-threonine o3-phosphate (hs-htp) to yield methane and the nonsymmetrical disulfide of 2-mercaptoethanesulfonic acid and hs-htp. we chemically synthesized modified analogs of ch3-s-com (which has two carbons in the ethylene ... | 1992 | 1732190 |
| isolation of a 5-hydroxybenzimidazolyl cobamide-containing enzyme involved in the methyltetrahydromethanopterin: coenzyme m methyltransferase reaction in methanobacterium thermoautotrophicum. | formaldehyde conversion into methyl-coenzyme m involves (a) reaction of the substrate with 5,6,7,8-tetrahydromethanopterin (h4mpt) giving 5,10-methylene-h4mpt, followed by its reduction to 5-methyl-h4mpt and (b) transfer of the methyl group from the latter compound to coenzyme m. the reactions were studied in a resolved system from methanobacterium thermoautotrophicum strain delta h. the first part (a) of the reactions was catalyzed by the 55% ammonium sulfate supernatant of cell-free extracts. ... | 1992 | 1737047 |
| 7-mercaptoheptanoylthreonine phosphate substitutes for heat-stable factor (mobile factor) for growth of methanomicrobium mobile. | methanomicrobium mobile requires a heat-stable factor present in ruminal fluid and in boiled cell extract from methanobacterium thermoautotrophicum for growth. by comparing the growth of m. mobile with boiled cell extract with that observed with various methanogenic cofactors, we found that 7-mercaptoheptanoylthreonine phosphate (hs-htp) supported sustained growth of m. mobile, at an optimal concentration of 100 microm. no derivatives or possible biosynthetic precursors of hs-htp could replace h ... | 1991 | 1746950 |
| inhibition of pure cultures of methanogens by benzene ring compounds. | the inhibition of methane production by methanosaeta concilii gp6, methanospirillum hungatei gp1, methanobacterium espanolae gp9, and methanobacterium bryantii m.o.h. during short-term (6-h) exposure to eight benzene ring compounds was studied. the concentration that caused 50% inhibition of the methane production rate (ic50) was dependent on the species and the toxicant. pentachlorophenol was the most toxic of the tested compounds, with an ic50 of less than 8 mg/liter for all species except m. ... | 1991 | 1746956 |
| biosynthesis of 5-hydroxybenzimidazolylcobamid (factor iii) in methanobacterium thermoautotrophicum. | cultures of methanobacterium thermoautotrophicum were supplemented with 13c-labeled acetate or pyruvate, and the labeling pattern of the corrinoid, factor iii, was established by 13c nmr spectroscopy. complete 13c signal assignments were obtained by two-dimensional nmr experiments. the labeling pattern of factor iii was analyzed by comparison with those of amino acids and nucleosides. the corrin ring system is derived from eight molecules of glutamate. the aminopropanol moiety is derived in a hi ... | 1991 | 1748658 |
| hydrogen-forming and coenzyme-f420-reducing methylene tetrahydromethanopterin dehydrogenase are genetically distinct enzymes in methanobacterium thermoautotrophicum (marburg). | a coenzyme-f420-reducing and an h2-forming methylenetetrahydromethanopterin dehydrogenase have been isolated from methanobacterium thermoautotrophicum (marburg). indirect evidence suggested that the former enzyme (32 kda) might be derived from the latter enzyme (42 kda) by proteolysis. to test this hypothesis the gene sequence of the h2-forming dehydrogenase was determined and compared with the n-terminal amino acid sequence of the f420-reducing dehydrogenase. no corresponding sequences were fou ... | 1991 | 1765081 |
| light sensitivity of methanogenic archaebacteria. | representatives of four families of methanogenic archaebacteria (archaea), methanobacterium thermoautotrophicum delta h, methanobacterium thermoautotrophicum marburg, methanosarcina acetivorans, methanococcus voltae, and methanomicrobium mobile, were found to be light sensitive. the facultative anaerobic eubacteria escherichia coli and salmonella typhimurium, however, were tolerant of light when grown anaerobically under identical light conditions. interference filters were used to show that gro ... | 1991 | 1768142 |