Topic
Methanosarcina barkeri
About: Methanosarcina barkeri is a research topic. Over the lifetime, 703 publications have been published within this topic receiving 32151 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: It is concluded that ATP is synthesized during methanogenesis by a chemiosmotic mechanism coupled to the methylcoenzyme M methylreductase and that Na + is not involved in this process.
14 citations
TL;DR: Thirty-seven strains of mesophilic and thermophilic methanogenic Archaea, belonging to 30 species, were analyzed by length polymorphism and single-strand conformation polymorphism of an amplified 300-bp fragment of the 16S rRNA gene, suggesting the presence of polymorphic 16S RRNA genes in the genome.
Abstract: Thirty-seven strains of mesophilic and thermophilic methanogenic Archaea, belonging to 30 species, were analyzed by length polymorphism (LP) and single-strand conformation polymorphism (SSCP) of an amplified 300-bp fragment of the 16S rRNA gene (Escherichia coli positions 9–331) including the variable regions V1 and V2. LPs and SSCPs were detected between species and between strains of the same species (Methanobacterium formicicum). LPs were found in Mb. formicicum DSMZ 3637, Mb. ivanovii DSMZ 2611, Mb. wolfei DSMZ 2970, Methanosarcina barkeri DSMZ 800, and Methanosaeta concilii DSMZ 3671, suggesting the presence of polymorphic 16S rRNA genes in the genome. We propose that LP and SSCP analysis of the 16S rRNA gene could be of practical help for strain identification.
14 citations
TL;DR: The general distribution of metals in cell compartments of Methanosarcina barkeri ‘Fusaro’ was studied by energy-dispersive X-ray microanalysis and the elemental pattern of Ca, P, and Fe could be seen in all cellcompartments.
Abstract: The general distribution of metals in cell compartments ofMethanosarcina barkeri ‘Fusaro’ was studied by energy-dispersive X-ray microanalysis. Cells were cultivated on methanol, acetate, or on a mixture of H2+CO2 as substrate. At decreasing degree (polyphosphate bodies ≫ clusters of small granula>cell walls, inside a cell clump> cytoplasma), the elemental pattern of Ca, P, and Fe could be seen in all cell compartments. Cells grown on methanol were further investigated for their ability to incorporate added heavy metal ions. After completed growth and methane production, Pb or Cd was found to a considerable extent in all cell compartments, whereas Zn or Cu was incorporated only to a minor degree. Evidence for an uptake of Hg could not be obtained.
14 citations
TL;DR: Cell extracts of Methanosarcina barkeri converted coenzyme F420 in an ATP-dependent reaction to the adenylylated derivative factor 390 in 7 of 11 extracts, all of which were prepared from different batches of cells.
Abstract: Cell extracts of Methanosarcina barkeri converted coenzyme F420 in an ATP-dependent reaction to the adenylylated derivative factor 390. Although it was reported previously (L. M. Gloss and R. P. Hausinger, BioFactors 1:237-240, 1988) that whole cells were unable to perform this conversion, we observed the conversion in 7 of 11 extracts, all of which were prepared from different batches of cells.
14 citations
TL;DR: The nitrogenase enzyme complex of Methanosarcina barkeri 227 was found to be more sensitive to NaCl than previously studied molybdenum nitrogenases are, with total inhibition of activity occurring at 190 mM NaCl, compared with >600 mMNaCl for Azotobacter vinelandii and Clostridium pasteurianum nitrogen enzymes.
Abstract: The nitrogenase enzyme complex of Methanosarcina barkeri 227 was found to be more sensitive to NaCl than previously studied molybdenum nitrogenases are, with total inhibition of activity occurring at 190 mM NaCl, compared with >600 mM NaCl for Azotobacter vinelandii and Clostridium pasteurianum nitrogenases. Na+ and K+ had equivalent effects, whereas Mg2+ was more inhibitory than either monovalent cation, even on a per-charge basis. The anion Cl- was more inhibitory than acetate was. Because M. barkeri 227 is a facultative halophile, we examined the effects of external salt on growth and diazotrophy and found that inhibition of growth was not greater with N2 than with NH4+. Cells grown with N2 and cells grown with NH4+ produced equal concentrations of alpha-glutamate at low salt concentrations and equal concentrations of Nepsilon-acetyl-beta-lysine at NaCl concentrations greater than 500 mM. Despite the high energetic cost of fixing nitrogen for these osmolytes, we obtained no evidence that there is a shift towards nonnitrogenous osmolytes during diazotrophic growth. In vitro nitrogenase enzyme assays showed that at a low concentration (approximately 100 mM) potassium glutamate enhanced activity but at higher concentrations this compound inhibited activity; 50% inhibition occurred at a potassium glutamate concentration of approximately 400 mM.
13 citations