ABSTRACT: Andean uncovered biosphere: revealing the vertical miliscale bacterial and eukaryotic community structure and relationships within a microbial mat from Salar de Huasco
Project description:Acute colorectal obstruction has been reported to occur in 7 - 29% of all colorectal malignancies, but emergent surgical decompression is associated with high morbidity and mortality rates. Recently, self-expandable metal stents(SEMS) have been suggested as an alternative to surgery and effectively decompress the colonic obstruction and allow for bowel preparation and elective surgery. Theoretically, SEMSs are classified into uncovered stents and covered stents. Covered stents have the advantage of less frequent stent occlusion by tumor in-growth and the disadvantage of a high risk of stent migration, whereas uncovered stents are associated with less stent migration, although they appear to be more prone to tumor ingrowth. To overcome the drawbacks of conventional stents, a double-layered combination covered stent was developed. In the present study, the investigators evaluated the efficacy and safety of the newly designed covered stent by comparing it with the uncovered stent in patients with malignant colorectal obstruction.
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.
