Project description:Experiment to understand relationships between sheep rumen wall transcriptome and microbial methane emissions
2017-12-30 | GSE81847 | GEO
Project description:Asparagopsis taxiformis dramatically reduces methane emissions in ruminants by affecting rumen microbial composition and inhibiting methyl-coenzyme M activity
Project description:Halogenases, and the halogenated organic molecules that they furnish are thought to be highly specialized secondary metabolites produced in only modest amounts. The widespread production of bromoform by marine macroalgae contradicts this paradigm wherein up to 8% dry weight of the red seaweed Asparagopsis taxiformis comprises of this brominated natural product. In this study, using paired transcriptomic and proteomic workflows, we determine that the bromoform-producing halogenase in A. taxiformis, Mbb1, is one of the most abundant proteins in the seaweed tissue with proteomic abundance rivaling that of enzymes involved in photosynthesis and carbon fixation. The proteomic abundance of Mbb1 is matched by the high transcript abundance of the mbb1 gene. Production of Mbb1 was found independent of the ecological source of the seaweed tissue with comparable transcript abundances detected between stress-free laboratory-cultivated, and appropriately stressed field-collected tissue samples. Taken together, these findings allow us to posit that bromoform production is not a stress-response or self-defense mechanism for A. taxiformis and instead fulfills a core metabolic role in marine macroalgal physiology.
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw. A 2m deep permafrost sample and it overlying active layer were sampled and their metagenome analysed. For microarray analyses, 8 other soil samples from the same region were used for comparison purposes.
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw.