Project description:A microarray analysis was conducted to analyze gene expression patterns in different tissues of the ECM interaction between Betula pendula and Paxillus involutus grown in peat microcosms containing (NH4)2SO4 nutrient patches. Expression profiles for mycorrhizal root tips (TIP), rhizomorphs (CORD) and the mycelium harvested from (NH4)2SO4 nutrient patches (PATCH) were compared. Our goal was to identify genes that showed nutrient- and tissue-specific differential regulation. <br> <br> The entire design involved 9 slides (DW1_01--DW1_09), 12 labelled extracts, and 3 biological replicates (R1-R3). The experiment was designed as a simple loop (all-pairwise comparisons) of the three tissues including dye-swap, biological and technical replication.
Project description:This project aims to investigate the metabolic pathways expressed by the active microbial community occurring at the deep continental subsurface. Subsurface chemoLithoautotrophic Microbial Ecosystems (SLiMEs) under oligotrophic conditions are supported by H2; however, the overall ecological trophic structures of these communities are poorly understood. Some deep, fluid-filled fractures in the Witwatersrand Basin, South Africa appear to support inverted trophic pyramids wherein methanogens contributing <5% of the total DNA apparently produce CH4 that supports the rest of the community. Here we show the active metabolic relationships of one such trophic structure by combining metatranscriptomic assemblies, metaproteomic and stable isotopic data, and thermodynamic modeling. Four autotrophic β-proteobacteria genera that are capable of oxidizing sulfur by denitrification dominate. They co-occur with sulfate reducers, anaerobic methane oxidizers and methanogens, which each comprises <5% of the total community. Defining trophic levels of microbial chemolithoautotrophs by the number of transfers from the initial abiotic H2-driven CO2 fixation, we propose a top-down cascade influence of the metabolic consumers that enhances the fitness of the metabolic producers to explain the inverted biomass pyramid of a multitrophic SLiME. Symbiotic partnerships are pivotal in the deep biosphere on and potentially beyond the Earth.
Project description:Microcosms made of filtered seawater innoculated with Enterococcus faecalis v583 were exposed to artificial sunlight to investigate photoinactivation mechanisms. Microcosms exposed to artificial sunlight were compared to dark controls. Three experiments were done on three separate days. During every experiment, the light and dark microcosms were samples at the begining (time = 0 hours) and then at 2, 6, 12 and 24 hours.
