Download or read book The Interaction Between Methanosarcina Barkeri and a Non methanogenic Associate written by Francis Henry Palmer and published by . This book was released on 1977 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book One and Two Carbon Catabolism in Methanosarcina Barkeri written by Joseph A. Krzycki and published by . This book was released on 1981 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies on the Physiology of Methanosarcina Barkeri written by Richard H. Wolkin and published by . This book was released on 1980 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methanogenesis from Methylamines in Methanosarcina Barkeri Fusaro written by Roeland Wilhelmus Wassenaar and published by . This book was released on 1999 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Methanosarcina Barkeri Genome written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report here a comparative analysis of the genome sequence of Methanosarcina barkeri with those of Methanosarcina acetivorans and Methanosarcina mazei. All three genomes share a conserved double origin of replication and many gene clusters. M. barkeri is distinguished by having an organization that is well conserved with respect to the other Methanosarcinae in the region proximal to the origin of replication with interspecies gene similarities as high as 95%. However it is disordered and marked by increased transposase frequency and decreased gene synteny and gene density in the proximal semi-genome. Of the 3680 open reading frames in M. barkeri, 678 had paralogs with better than 80% similarity to both M. acetivorans and M. mazei while 128 nonhypothetical orfs were unique (non-paralogous) amongst these species including a complete formate dehydrogenase operon, two genes required for N-acetylmuramic acid synthesis, a 14 gene gas vesicle cluster and a bacterial P450-specific ferredoxin reductase cluster not previously observed or characterized in this genus. A cryptic 36 kbp plasmid sequence was detected in M. barkeri that contains an orc1 gene flanked by a presumptive origin of replication consisting of 38 tandem repeats of a 143 nt motif. Three-way comparison of these genomes reveals differing mechanisms for the accrual of changes. Elongation of the large M. acetivorans is the result of multiple gene-scale insertions and duplications uniformly distributed in that genome, while M. barkeri is characterized by localized inversions associated with the loss of gene content. In contrast, the relatively short M. mazei most closely approximates the ancestral organizational state.

Download or read book The Metabolism of One carbon Compounds and Acetate by Methanosarcina Barkeri written by Paul J. Weimer and published by . This book was released on 1978 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diazotrophy and Nitrogenase in Methanosarcina Barkeri Strain 227 written by Anthony Lawrence Lobo and published by . This book was released on 1990 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nitrogen Fixation and Its Regulation in the Archaeon Methanosarcina Barkeri 227 written by Yueh-tyng Chien and published by . This book was released on 1996 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Hydrogen Metabolism in Methanosarcina Barkeri Fusaro written by Gargi Kulkarni and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methanogens utilize an unusual energy-conserving electron transport chain that involves reduction of a limited number of electron acceptors to methane (CH4) gas. Previous biochemical studies suggest that the proton pumping F420H2 dehydrogenase (Fpo) plays a crucial role in this process during growth on methanol. However, Methanosarcina barkeri 8́6fpo mutants investigated in Chapter 2 display no measurable phenotype on this substrate. In contrast, 8́6frh mutants lacking the cytoplasmic F420-dependent hydrogenase (Frh) are severely affected in their ability to grow and make methane from methanol, while double 8́6fpo 8́6frh mutants are completely unable to utilize this substrate. These data suggest that while M. barkeri has the flexibility to use the Fpo-dependent electron transport chain when needed, the preferred energy conservation pathway involves production of H2 gas by Frh hydrogenase within the cytoplasm. The H2 can then diffuse out of the cell, where it can be oxidized by the periplasmic methanophenazine-dependent hydrogenase (Vht), with transfer of electrons into the electron transport chain. Consistent with this 0́−H2-cycling0́+ proposal, a conditional vht mutant isolated in Chapter 3, is unable to grow using any of the methanogenic substrates tested under non-permissive conditions, suggesting that Vht is essential for growth of M. barkeri. Moreover, repression of vht expression results in a rapid increase in H2 partial pressure, which supports the hypothesis that Vht is required for H2 uptake. H2 accumulation in the culture headspace of conditional vht mutant is accompanied with cessation of methanogenesis and growth, implying that H2 uptake is essential for anaerobic respiration and viability. In contrast, Vht is not essential in mutants lacking the H2-producing Frh hydrogenase. This is consistent with the hypothesis that Vht is required for H2 uptake, only when Frh produces H2, that is, Frh and Vht hydrogenases are functionally coupled in a 0́−H2-cycling0́+ energy conservation mechanism. Because production of H2 by Frh consumes protons within the cytoplasm and oxidation of H2 by Vht releases protons outside the cell, this electron transport chain is capable of establishing a trans-membrane proton gradient that can be used to make ATP by the ATP synthase. Our study provides the first direct experimental evidence for H2-cycling, since it was proposed to be involved in energy conservation in sulfate-reducing bacteria in 1981. To further dissect the roles of these hydrogenases in M. barkeri physiology, I constructed a series of hydrogenase deletion mutants in various combinations in Chapter 4, including a mutant that is devoid of all three types of hydrogenases, ferredoxin-dependent Ech, Frh and Vht. My data show that each of the three types of hydrogenases is needed for growth via the CO2 reduction pathway. In contrast, none of the hydrogenases is essential during methylotrophic growth, indicating the presence of H2-independent electron transport chains, which are able to support wild-type growth yields. Either Vht or Ech hydrogenase alone can support growth using the methyl respiration pathway. However, both Ech and Vht hydrogenases are required for acetate utilization. The data presented in chapter 4 also suggest that Ech and/or Frh hydrogenases block the methyl oxidative pathway by catalyzing conversion of H2 to Fdred and F420H2, respectively. In addition, evidence is provided for involvement of Hyp proteins in maturation of Ech hydrogenase. This work highlights the similarities and differences between H2-independent electron transport chains of the hydrogenotroph M. barkeri and the non-hydrogenotroph Methanosarcina acetivorans.

Download or read book An Updated Genome Scale Metabolic Reconstruction of Methanosarcina Barkeri written by Matthew C. Gonnerman and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methanosarcina barkeri is a methanogen, meaning that methane is the reduced product for energy generation. M. barkeri can grow on several substrates including methanol, acetate, methyl amines and a combination of hydrogen and carbon dioxide. The Methanosarcina barkeri genome was published in 2006 after the metabolic reconstruction of M. barkeri, iAF692, was published. The iAF692 reconstruction preformed the first large scale simulations of an Archaea. Since the publication of iAF692, a deeper understanding of Archaea biology has shed light on previously unclear metabolic pathways. For methanogenesis, proton pumping has been updated to reflect an improved knowledge of the pathway. Cofactor biosynthesis has been updated to reflect a better understanding of methanogen anabolism. Metabolic networks such as pentose phosphate pathway, amino acid biosynthesis, and cell wall composition have also been updated to reflect Archaea specific biosynthesis pathways. This improved insight has led to an increase in predictive accuracy for knockouts and growth yield predictions for the updated M. barkeri reconstruction, iMG750. As with other metabolic reconstructions, iMG750 will be a useful tool in guiding experimental studies and predicting cellular behavior on a genome scale.

Download or read book Methanogenesis from Methylamines in methanosarcina Barkeri Fusaro written by Roel Wassenaar and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemostat Growth Studies and Bioenergetic Aspects of Methanosarcina Barkeri written by John Palmer and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Initial Adhesion of Methanosarcina Barkeri to Support Materials written by Akinori Yoshihara and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methanol dependent Methyl Transfer Reactions in Methanosarcina Barkeri written by Petrus Johannes Henricus Daas and published by . This book was released on 1996 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Methylotrophic Methanogenesis in Methanosarcina Barkeri Fusaro written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification and Isolation of Methylated Corrinoid Proteins from Acetate grown Methanosarcina Barkeri written by Xianjun Cao and published by . This book was released on 1991 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electron Transport in Methanosarcina written by Adam M. Guss and published by . This book was released on 2006 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron transport during methanogenesis in the freshwater methanogen Methanosarcina barkeri is known to utilize hydrogenases to transfer electrons from ferredoxin to methanophenazine. This thesis characterizes electron transport in the marine methanogen Methanosarcina acetivorans. Genomic comparison of hydrogenase gene clusters reveals that M. acetivorans encodes three putative Ni-Fe hydrogenases common to all sequenced Methanosarcina. However, deletion analysis and enzymatic assays indicate M. acetivorans does not produce functional hydrogenase in crude cell extract. This raised the possibility that M. acetivorans contains a unique electron transport chain distinct from that found in M. barkeri. To address the mechanism of M. acetivorans hydrogenase inactivation, reporter gene fusions to the hydrogenase promoters of M. acetivorans and M. barkeri were inserted into the chromosomes of both M. acetivorans and M. barkeri. The M. barkeri promoters were expressed in both organisms, while the M. acetivorans promoters were not expressed in either organism. This suggests that the M. acetivorans hydrogenases have been inactivated via cis-acting mutations in the promoters. Because M. acetivorans cannot use hydrogenases for electron transport, some other pathway must exist. Three putative oxidoreductase gene clusters have been implicated in this electron transport chain in M. acetivorans: rnf, ehr, and MA3739-3743. Deletion analysis of these three gene clusters indicates Rnf is the primary oxidoreductase during growth on acetate. While the Deltaehr and DeltaMA3739-3743 strains have growth phenotypes identical to the parent strains, the Deltarnf strain does not grow on acetate, grows more slowly on methanol, and has a ca. 300 hour lag period before growth on methanol + pyruvate. These data suggest that Rnf is a ferredoxin-dependent oxidoreductase involved in electron transport during methanogenesis in M. acetivorans.