Methanosarcina barkeri (DSM 800) is a metabolically versatile methanogen and shows distinct metabolic status under different substrate regimes. However, the mechanisms underlying distinct transcriptional profiles under different substrate regimes remain elusive. In this study, based on transcriptional analysis, the growth performances and gene expressions of M. barkeri fed on acetate, H2 + CO2, and methanol, respectively, were investigated. M. barkeri showed higher growth performances under methanol, followed by H2 + CO2 and acetate, which corresponded well with the variations of gene expressions. The α diversity (evenness) of gene expressions was highest under the acetate regime, followed by H2 + CO2 and methanol, and significantly and negatively correlated with growth performances. The gene co-expression analysis showed that "Energy production and conversion," "Coenzyme transport and metabolism," and "Translation, ribosomal structure, and biogenesis" showed deterministic cooperation patterns of intra- and inter-functional classes. However, "Posttranslational modification, protein turnover, chaperones" showed exclusion with other functional classes. The gene expressions and especially the relationships among them potentially drove the shifts of metabolic status under different substrate regimes. Consequently, this study revealed the diversity-related ecological strategies that a high α diversity probably provided more fitness and tolerance under natural environments and oppositely a low α diversity strengthened some specific physiological functions, as well as the co-responses of gene expressions to different substrate regimes.

• MeSH
• archeální RNA genetika   MeSH
• Euryarchaeota genetika   metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• kultivační média chemie   MeSH
• kyselina octová chemie   MeSH
• methanol chemie   MeSH
• Methanosarcina barkeri genetika   metabolismus   MeSH
• oxid uhličitý chemie   MeSH
• regulace genové exprese u archeí MeSH
• sekvenční analýza RNA MeSH
• substrátová specifita MeSH
• transkriptom * MeSH
• vodík chemie   MeSH
• Publikační typ
• časopisecké články MeSH

Pelomyxa palustris is a giant anaerobic/microaerobic amoeba, characterized by a number of exceptional cytological and physiological features, among them the presumed absence of energy producing organelles and the presence of endosymbiotic bacteria. These endosymbionts have been previously distinguished as: a large rectangular-shaped Gram-variable rod with a central cleft; a slender Gram-negative rod; and a slender Gram-positive rod. Using DNA extracted from P. palustris cysts, we have obtained three SSU rRNA gene sequences. We have determined that these sequences are affiliated to three different prokaryotic genera: Methanosaeta (a methanogenic archaea), Syntrophorhabdus (a syntrophic Gram-negative bacteria) and Rhodococcus (an aerobic chemoorganotrophic Gram-positive bacteria). To our knowledge, it is the first time that Syntrophorhabdus has been described as an endosymbiont in association with a methanogen. Strikingly, no traces of Methanobacterium formicicum could be detected, despite this methanogen had allegedly been isolated from trophozoites of P. palustris. It seems that the host and the endosymbionts have established a multipartite syntrophic consortium resembling to some extent those found in sewage treatment plants.

• MeSH
• Archamoebae mikrobiologie   fyziologie   MeSH
• archeální RNA genetika   MeSH
• bakteriální RNA genetika   MeSH
• Deltaproteobacteria klasifikace   genetika   izolace a purifikace   fyziologie   MeSH
• fylogeneze MeSH
• Methanosarcinales klasifikace   genetika   izolace a purifikace   fyziologie   MeSH
• Rhodococcus klasifikace   genetika   izolace a purifikace   fyziologie   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza RNA MeSH
• symbióza * MeSH
• Publikační typ
• časopisecké články MeSH

The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g-1 d-1, which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments.

• MeSH
• geologické sedimenty mikrobiologie   MeSH
• ledový příkrov mikrobiologie   MeSH
• methan MeSH
• Methanomicrobiales MeSH
• Methanosarcinales MeSH
• mikrobiota * MeSH
• Peptococcaceae MeSH
• řeky mikrobiologie   MeSH
• sírany MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Grónsko MeSH

The variation in the diversity of methanogens in sediment depths from Sitka stream was studied by constructing a 16S rRNA gene library using methanogen-specific primers and a denaturing gradient gel electrophoresis (DGGE)-based approach. A total of nine different phylotypes from the 16S rRNA library were obtained, and all of them were clustered within the order Methanosarcinales. These nine phylotypes likely represent nine new species and at least 5-6 new genera. Similarly, DGGE analysis revealed an increase in the diversity of methanogens with an increase in sediment depth. These results suggest that Methanosarcinales phylotypes might be the dominant methanogens in the sediment from Sitka stream, and the diversity of methanogens increases as the depth increases. Results of the present study will help in making effective strategies to monitor the dominant methanogen phylotypes and methane emissions in the environment.

• MeSH
• denaturační gradientová gelová elektroforéza MeSH
• DNA archebakterií chemie   genetika   MeSH
• fylogeneze MeSH
• geologické sedimenty mikrobiologie   MeSH
• Methanosarcinales izolace a purifikace   MeSH
• molekulární sekvence - údaje MeSH
• řeky MeSH
• ribozomální DNA chemie   genetika   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• společenstvo * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH