Project description:Pristine groundwater is a highly stable environment with microbes adapted to dark, oligotrophic conditions. Input events like heavy rainfalls can introduce excess particulate organic matter including surface-derived microbes into the groundwater, hereby creating a disturbance to the groundwater microbiome. Some of the translocated bacteria are not able to thrive in groundwater and will form necromass. Here, we investigated the effects of necromass addition to the microbial community in fractured bedrock groundwater, using groundwater mesocosms as model systems. We followed the uptake of 13C-labeled necromass by the bacterial and eukaryotic groundwater community quantitatively and over time by employing a combined protein and DNA stable isotope probing approach. Necromass was rapidly depleted in the mesocosms within four days, accompanied by a strong decrease of Shannon diversity and an increase of bacterial 16S rRNA gene copy numbers by one order of magnitude. Species of Flavobacterium, Massilia, Rheinheimera, Rhodoferax and Undibacterium dominated the microbial community within two days and were identified as key players in necromass degradation, based on a 13C incorporation of > 90% in their peptides. Their proteomes showed various uptake and transport related proteins, and many proteins involved in metabolizing amino acids. After four and eight days of incubation, autotrophic and mixotrophic groundwater species of Nitrosomonas, Limnohabitans, Paucibacter and Acidovorax increased in abundance, with a 13C incorporation between 0.5 and 23%. Our data point towards a very fast and exclusive uptake of labeled necromass by a few specialists followed by a concerted action of groundwater microorganisms, including autotrophs presumably fueled by released, reduced nitrogen and sulfur compounds generated during necromass degradation.
Project description:Groundwater-derived microorganisms are known to play an important role in biogeochemical C, S and N cycling. Thereby, the presence and majorly the activity of microorganisms in aquifers affect enormously the nutrient cycling. However, the diversity and their functional capability in natural aquifers are still rare and therefore a better knowledge of the core microbial communities is urgently needed. Metaproteome analysis was applied to characterize the repertoire of microbes in the depth and to identify the key drivers of major biogeochemical processes. Therefore, 1000 L water from the aquifer was sampled by filtration on 0.3 µm glass filters. After protein extraction, proteolytic cleavage and mass spectrometric analysis (Ultimate 3000 nanoRSLC coupled to Q Exactive HF instrument), 3808 protein groups (2371 proteins with ≥2 peptides) were identified from 13,204 peptides. The findings of our study have broad implications for the understanding of aquifer cycling’s which finally leads to a greatly improved understanding of the ecosystem services provided by the microbial communities present in aquifers. In the future, functional results would allow to monitor and to assess pollution effects which would beneficially assist groundwater resource management.
Project description:Background. Bacteria of the Candidate Phyla Radiation (CPR), constituting about 25% of the bacterial biodiversity, are characterized by small cell size and patchy genomes without complete key metabolic pathways suggesting symbiotic life styles. Gracilibacteria (BD1-5) are part of the CPR branch, they possess alternate coded genomes and have two cultivated members that were shown to be microbial predators. However, besides genomic sampling, little is known about the lifestyle of Gracilibacteria, their temporal dynamics, and activity in natural ecosystems, and particularly groundwater where they have initially been genomically resolved. The current study was set out with the aim of investigating the metaproteogenome of Gracilibacteria as a function of time in the cold-water geyser Wallender Born in the Volcanic Eifel region in Germany, to estimate their activity in situ and discern expressed genes involved in their lifestyle. Results. We coupled genome-resolved metagenomics and metaproteomics to investigate a microbial community enriched in Gracilibacteria across a 12-day time-series. Groundwater was collected and sequentially filtered onto 0.2-μm and 0.1-μm filters to fraction CPR and other bacteria. Based on 670 Gbps of metagenomic data, 1129 different ribosomal protein S3 marker genes and 751 high-quality genomes (123 population genomes after dereplication), we identified dominant bacteria belonging to Galionellales and Gracilibacteria along with keystone microbes, low in genomic abundance but substantially contributing to proteomic abundance. Seven high-quality Gracilibacteria genomes showed typical limitations in their central metabolism but no co-occurrence to potential hosts. Their genomes encoded for a high number of proteins related to a predatory lifestyle, whose expression was detected in the proteome and included subunits related to type IV and type II secretion systems, as well as features related to cell-cell interactions and cell motility. Conclusion. We present a highly resolved analysis coupling metagenomics to metaproteomics for elucidating microbial dynamics of Gracilibacteria in groundwater. We posit that Gracilibacteria are successful microbial predators in this ecosystem potentially aiding in population control of this highly disturbed microbial community from the deep biosphere.
2024-08-08 | PXD042980 | Pride
Project description:Microbial community in high arsenic geothermal groundwater
Project description:Primary objectives: The primary objective is to investigate circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Primary endpoints: circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
| 2533916 | ecrin-mdr-crc
Project description:Biodiversity survey of autotrophic microbes in acidic geothermal areas
Project description:We investigated an alga-dominated geothermal spring community in Yellowstone National Park (YNP), USA to determine how the biota cope with abiotic stressors. Microbes showed a community level response to toxic metal resistance and energy cycling that spans the three domains of life. Arsenic detoxification is accomplished via complementary expression of genes by different lineages. Photosynthetic primary production is dominated by the obligate photoautotrophic alga Cyanidioschyzon, with the mixotroph, Galdieria, largely relegated to nighttime heterotrophy. Many key functions, including the cell cycle, are strongly regulated by diurnal fluctuations in light and nutrients. These results demonstrate that biotic interactions are highly structured and constrained in extreme habitats. We suggest this was also the case on the early Earth when geothermal springs were cradles of microbial life.
The work (proposal:https://doi.org/10.46936/10.25585/60000481) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231.
Project description:Crassulacean acid metabolism (CAM) is a water-use efficient adaptation of photosynthesis that has evolved independently many times in diverse lineages of flowering plants. We hypothesize that convergent evolution of protein sequence and temporal gene expression underpins the independent emergences of CAM from C3 photosynthesis. To test this hypothesis, we generated a de novo genome assembly and genome-wide transcript expression data for Kalanchoe fedtschenkoi, an obligate CAM species within the core eudicots with a relatively small genome (~260 Mb). Our comparative analyses identified signatures of convergence in protein sequence and re-scheduling of diel transcript expression of genes involved in nocturnal CO2 fixation, stomatal movement, heat tolerance, circadian clock and carbohydrate metabolism in K. fedtschenkoi and other CAM species in comparison with non-CAM species. These findings provide new insights into molecular convergence and building blocks of CAM and will facilitate CAM-into-C3 photosynthesis engineering to enhance water-use efficiency in crops.