Showing papers on "Methanosarcina barkeri published in 1980"

Methane formation from fructose by syntrophic associations of Acetobacterium woodii and different strains of methanogens.

Abstract: When Acetobacterium woodii was co-cultured in continuous or in stationary culture with Methanobacterium strain AZ, fructose instead of being converted to 3 mol of acetate was converted to 2 mol of acetate and 1 mol each of carbon dioxide and methane, showing that interspecies hydrogen transfer occurred. In continous culture the organisms formed a close physical association in clumps; the doubling time for each organism was 6h at 33°C. Methane mainly was derived from carbon positions 3 and 4 of the sugar, but other carbons also yielded methane; this was shown to be due to carbon dioxide-acetate exchange reactions by A. woodii in a manner similar to that carried out by Clostridium thermoaceticum. Four other methanogens, Methanobacterium M.o.H. and M.o.H. G, Methanobacterium formicicum, and Methanosarcina barkeri (not acetate-adapted) also produced similar results, when co-cultured with A. woodii.

Methyl-coenzyme M, an intermediate in methanogenic dissimilation of C1 compounds by Methanosarcina barkeri.

Abstract: Extracts of Methanosarcina barkeri possess a specific methyltransferase that catalyzes the transfer of the methyl group of methanol to 2-mercaptoethanesulfonic acid. Over a fourfold range in added 2-mercaptoethanesulfonic acid, the formation of 2-(methylthio)ethanesulfonic acid exhibited a 1:1 ratio to 2-mercaptoethanesulfonic acid added. This reaction required adenosine 5'-triphosphate; a maximal ratio (mole/mole) of 85 methyl groups was transferred per adenosine 5'-triphosphate added. The methyltransferase was found in extracts of methanol-grown cells as well as in extracts of hydrogen-grown cells. In extracts of cells grown on either substrate, 2-(methylthio)ethanesulfonic acid was formed from added methanol or methylamine but not from acetate.

Acetate, methanol and carbon dioxide as substrates for growth of Methanosarcina barkeri.

Abstract: Methanosarcina barkeri grows in defined media with acetate, methanol or carbon dioxide as carbon sources. Methanol is used for methanogenesis at a 5 times higher rate as compared with other substrates. M. barkeri can use the substrates simultaneously, but due to acidification or alkalification of the medium during growth on methanol or acetate, respectively, growth and methano-genesis may stop before the substrates are exhausted. Growth and methano-genesis on methanol or acetate are inhibited by the presence of an excess of H2; the inhibition is abolished by the addition of carbon dioxide, which probably serves as an essential source of cell carbon, in the absence of which methano-genesis ceases.

Unusual modification patterns in the transfer ribonucleic acids of archaebacteria

Abstract: The modification patterns of the transfer RNAs of ten archaebacteria (Halobacterium volcanii, Halococcus morrhuae, Methanobacterium bryantii, Methanobrevibacter smithii, Methanococcus vannielii, Methanococcus voltae, Methanomicrobium mobile, Methanosarcina barkeri, Thermoplasma acidophilum, andSulfolobus acidocaldarius) were analyzed by two-dimensional thin-layer chromatography of the32P-labeled nucleotides. All species lack ribothymidine and 7-methylguanosine, and dihydrouridine is absent from all butM. barkeri. Pseudouridine, 2′-O-methylcytidine, 1-methylguanosine, andN 2,N 2-dimethylguanosine are present in all of them; except forM. barkeri andT. acidophilum, all haveN 2-methylguanosine. All, exceptH. volcanii andH. morrhuae, contain 1-methyladenosine, and these two organisms andS. acidocalderius only contain 5-methylcytidine. The transfer RNA modification patterns of the archaebacteria are distinct from those of typical eubacteria (Escherichia coli) and typical eukaryotes (Saccharomyces cerevisiae), although they are somewhat more similar to the latter than the former.

Effect of adenosine 5'-monophosphate on adenosine 5'-triphosphate activation of methyl coenzyme M methylreductase in cell extracts of Methanosarcina barkeri.

Abstract: In cell extracts of Methanosarcina barkeri, adenosine 5'-triphosphate (ATP)-activated methyl coenzyme M methylreductase was inhibited by adenosine 5'-monophosphate (AMP) but not by cyclic AMP. AMP (2 and 4 mM) shifted the saturation curve for ATP activation from hyperbolic (Hill coefficient [n] = 1.0) to sigmoidal (n = 1.5), decreased Vmax, and increased the apparent KmATP.

Membranes of bacteria lacking peptidoglycan

Abstract: Bacteria lacking peptidoglycan come into four main categories: Mycoplasmas, bacterial L-forms, halobacteria and methanogenic bacteria. The last-named were only recently identified as falling in this class, when Kandier and Hippe [14] showed that the walls of Methanosarcina barken and some other species lacked muramic acid, glucosamine and D-glutamic acid. The structural component of the wall of M. barkeri consisted of galactosamine, uronic acids, glucose and a little galactose and thus resembled that of Halococcus morrhuae (see below) except that it was not sulphated. Further evidence has now indicated that many of the Methanobacteria have walls containing ‘pseudomurein’ (see Chapter 6) and that they may be considered as a group along with the Halobacteria, Thermosplasma and Sulfolobus to form a separate kingdom of prokaryotes designated Archaebacteria [66].