Methanosarcina barkeri

About: Methanosarcina barkeri is a research topic. Over the lifetime, 703 publications have been published within this topic receiving 32151 citations.

Presence of a human Hyaluronan binding protein 1 (HABP1) pseudogene-like sequence in Methanosarcina barkeri suggests its linkage in evolution

Abstract: The gene encoding Hyaluronan binding protein 1 (HABP1) and its homologs have been reported across eukaryotes, from yeast to human. We have reported the presence of processed pseudogenes in several human chromosomes, along with the location of the HABP1 gene on chromosome 17p12-p13. In this study, we report not only the presence of HABP1 pseudogene in other animal species, but also the presence of a homologous sequence in Methanosarcina barkeri, an ancient life form. This sequence has 44.8% homology to the human HABP1 cDNA and 45.3% homology with the HABP1 pseudogene in human chromosome 21. This sequence has a high G + C content (57%), characteristic of archaea, a family to which M. barkeri belongs. The presence of this HABP1 cDNA like fragment in M. barkeri might enable us to shed light on the evolution of the HABPl gene and whether it was present in a common ancestral organism before the lineages separated.

Dual RNase and β-lactamase activity of a single enzyme encoded in most Archaea

Abstract: β-lactams targeting the bacterial cell wall are not active on archaea. Here, we figure out that annotation of genes as β-lactamase in Archeae on the basis of homologous genes, initially annotated β-lactamases, is a remnant of the identification of the original activities of this group of enzymes, which in fact, have multiple functions including nuclease, ribonuclease, β-lactamase, or glyoxalase; which may specialized over time. We expressed a class B β-lactamase enzyme from Methanosarcina barkeri that digest penicillin G. Moreover, while a weak glyoxalase activity was detected, a significant ribonuclease activity on bacterial and synthetic RNAs was demonstrated. The β-lactamase activity was inhibited by a β-lactamase inhibitor (sulbactam), but its RNAse activity was not. This gene appears to has been transferred to the Flavobacteriaceae group including Elizabethkingia genus in which the expressed gene shows a more specialized activity toward resistance to tienanmicin but no glyoxalase activity. The expressed class C-like β-lactamase gene, also from Methanosarcina sp., shows also hydrolysis activity and was more closely related to DD-peptidase enzymes than known bacterial class C β-lactamases. Our findings highlight the requalification needness of annotated enzymes as β-lactamases and the specification overtime of multipotent enzymes in different ways in Archaea and bacteria.

Pure culture, co-culture and whole ecosystem investigations of single anaerobes, partnerships and microbial communities in anaerobic digestion

Abstract: Anaerobic Digestion (AD) comprises the microbiological breakdown of complex organic materials in the absence of oxygen to produce biogas, which can be used as a renewable fuel. However, there is a knowledge gap regarding the microbiology that underpins the AD process, especially the specific synergies and competitions, between the individual species involved. Growth and substrate consumption profiles of pure cultures, and co-cultures, of three model AD organisms, Methanosarcina barkeri, Acetobacterium woodii and Methanococcus maripaludis, were investigated to determine their interactions under H2-CO2 and acetate feeding at both moderate and low temperatures. A common medium was also used for two of the strains for this study. Temporal CH4 and volatile fatty acid (VFA) concentrations in assays were determined for all combinations at each growth phase. Results showed that the substrates and temperatures strongly influenced the growth rates of each strain and co-culture. M. barkeri grew fastest in H2-CO2 at 37°C (doubling time (dt): 12.44 hours) compared to under acetate (dt: 34.34 hours) or at 15°C (dt: 28.25 hours). A. woodii grew fastest in H2-CO2 at 35°C (dt: 17.13 hours) compared to at 15°C in H2-CO2 (dt: 27.90 hours) and M. maripaludis grew at an optimum of dt = 32.30 hours in the CP medium on its preferred substrate H2-CO2 as the main energy source, at 37°C. Cocultures of M. barkeri partnered with A. woodii and M. barkeri partnered with M. maripaludis demonstrated the impact of competitions on their pure culture counterparts regarding growth and metabolisms. Future studies will include analyses of individual strains and mixed-species consortia by genomics and transcriptomics, and metagenomics and metatranscriptomics, respectively.

Paradoxical β-lactamase activity of archaeal encoding enzymes

Abstract: {beta}-lactams targeting the bacterial cell wall are not efficient on archaea. Using phylogenetic analysis and common ancestor sequences for bacterial {beta}-lactamases, we found serendipitously class B and class C-like {beta}-lactamase genes in most archaea genomes. The class B {beta}-lactamase appears to be highly conserved in archaea and to has been transferred in the bacterial genus Elizabethkingia. The experimentaly expressed class B enzyme from Methanosarcina barkeri was able to digest penicillin G and was inhibited by a {beta}-lactamase inhibitor (i.e. sulbactam). The class C-like {beta}-lactamase was more closely related to DD-peptidase enzymes than know bacterial class C {beta}-lactamases. The use of these very conserved genes in this domain cannot be explored as a defense system against {beta}-lactams but may be used to feed {beta}-lactams as a source of carbon as shown in bacteria.