Project description:The objective was to identify functional genes encoded by Fungi and fungal-like organisms to assess putative ecological roles Using the GeoChip microarray, we detected fungal genes involved in the complete assimilation of nitrate and the degradation of lignin, as well as evidence for Partitiviridae (a mycovirus) that likely regulates fungal populations in the marine environment. These results demonstrate the potential for fungi to degrade terrigenously-sourced molecules, such as permafrost and compete with algae for nitrate during blooms. Ultimately, these data suggest that marine fungi could be as important in oceanic ecosystems as they are in freshwater environments.
Project description:The objective of this study was to identify the different functional genes involved in key biogeochemical cycles in the low Arctic regions. Understanding the microbial diversity in the Arctic region is an important step to determine the effects of climate change on these areas.
Project description:The objective of this study was to identify the different functional genes involved in key biogeochemical cycles in thehigh Arctic regions. Understanding the microbial diversity in the Arctic region is an important step to determine the effects of climate change on these areas.
Project description:The objective of this study was to identify the different functional genes involved in key biogeochemical cycles in the sub- Arctic regions. Understanding the microbial diversity in the Arctic region is an important step to determine the effects of climate change on these areas.
Project description:Understanding biological diversity and distribution patterns at multiple spatial scales is a central issue in ecology. Here, we investigated the biogeographical patterns of functional genes in soil microbes from 24 arctic heath sites using GeoChip-based metagenomics and principal coordinates of neighbour matrices (PCNM)-based analysis. Functional gene richness varied considerably among sites, while the proportions of each major functional gene category were evenly distributed. Functional gene composition varied significantly at most medium and broad spatial scales, and the PCNM analyses indicated that 14-20% of the variation in total and major functional gene categories could be attributed primarily to relatively broad-scale spatial effects that were consistent with broad-scale variation in soil pH and total nitrogen. The combination of variance partitioning and multi-scales analysis indicated that spatial distance effects contributed 12% to variation in functional gene composition,whereas environmental factors contributed only 3%. This relatively strong influence of spatial as compared to environmental variation in determining functional gene distributions contrasts sharply with typical microbial phylotype/species-based biogeographical patterns in the Arctic and elsewhere. Our results suggest that the distributions of soil functional genes cannot be predicted from phylogenetic distributions because spatial factors associated with historical contingencies are relatively important determinants of their biogeography.
Project description:Cold seeps are characterized by high biomass, which is supported by the microbial oxidation of the available methane by capable microorganisms. The carbon is subsequently transferred to higher trophic levels. South of Svalbard, five geological mounds shaped by the formation of methane gas hydrates, have been recently located. Methane gas seeping activity has been observed on four of them, and flares were primarily concentrated at their summits. At three of these mounds, and along a distance gradient from their summit to their outskirt, we investigated the eukaryotic and prokaryotic biodiversity linked to 16S and 18S rDNA. Here we show that local methane seepage and other environmental conditions did affect the microbial community structure and composition. We could not demonstrate a community gradient from the summit to the edge of the mounds. Instead, a similar community structure in any methane-rich sediments could be retrieved at any location on these mounds. The oxidation of methane was largely driven by anaerobic methanotrophic Archaea-1 (ANME-1) and the communities also hosted high relative abundances of sulfate reducing bacterial groups although none demonstrated a clear co-occurrence with the predominance of ANME-1. Additional common taxa were observed and their abundances were likely benefiting from the end products of methane oxidation. Among these were sulfide-oxidizing Campilobacterota, organic matter degraders, such as Bathyarchaeota, Woesearchaeota, or thermoplasmatales marine benthic group D, and heterotrophic ciliates and Cercozoa.
Project description:Transcriptomic sequencing was performed to obtain the key functional genes involved in the adaptation of oxidative stress induced by hydrogen peroxide (H2O2) in the Arctic bacterium Pseudoalteromonas sp. A2. Exposure to 1 mmol/L H2O2 resulted in large alterations of the transcriptome profile, including significant upregulation of 109 genes and significant downregulation of 174 genes. Functional classification of differentially expressed genes revealed that most of genes affiliated with biological adhesion, negative regulation of biological process, enzyme regulator activity, protein binding transcription factor activity and structural molecular activity were upregulated, and most of genes affiliated with multicellular organismal process and extracellular region were downregulated. It was notably that fifteen genes affiliated with flagella and four genes affiliated with heat shock proteins were significantly upregulated. Meanwhile, nine genes affiliated with cytochrome and cytochrome oxidase, and five genes affiliated with TonB-dependent receptor, were significantly downregulated. However, eighteen genes with antioxidant activity categorized by GO analysis showed differential expressions. This overall survey of transcriptome and oxidative stress-relevant genes can contribute to understand the adaptive mechanism of Arctic bacteria. five significant upregulated genes and five significant downregulated genes were selected using qRT-PCR to cinduct the oxidative stress. overall survey of transcriptomic sequencing by RNA-Seq of the Pseudoalteromonas sp. A2, an isolate from seawater with high activity against H2O2