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:A functional microarray targeting 24 genes involved in chlorinated solvent biodegradation pathways has been developed and used to monitor the gene diversity present in four trichloroethylene (TCE) contaminated sites under ERD (enhanced reductive dechlorination) treatment. The microarray format provided by NimbleGen and used in this study is 12x135K. 2 µg of labelled gDNA from 30 groundwater samples were hybridized on the microarrays.
2012-04-03 | GSE28606 | GEO
Project description:groundwater microbial community diversity
| PRJNA735065 | ENA
Project description:groundwater microbial community diversity
| PRJNA1000736 | ENA
Project description:Microbial diversity of contaminated groundwater
Project description:Four stable and robust TCE-dechlorinating microbial communities were enriched from TCE-contaminated groundwater under four different conditions exploring two parameters, high and low methanogenic activity (Meth and NoMeth), with and without vitamin B12 supplement (MethB12 and NoMethB12, Meth and NoMeth, respectively). Identical amounts of lactate (2.7 mmol) and TCE (20 μl) were supplied as electron donor and electron acceptor. All four cultures were capable of reductively dechlorinating TCE to VC and ethene. Genomic DNA of the four enrichments was applied on a quad-Dhc-genome microarray in order to characterize the gene content of Dehalococcoides species present in the four enrichments
Project description:To effectively monitor microbial populations in acidic environments and bioleaching systems, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the known genes associated with the acidophiles. This array contained 1,072 probes in which there were 571 related to 16S rRNA and 501 related to functional genes. Acid mine drainage (AMD) presents numerous problems to the aquatic life and surrounding ecosystems. However, little is known about the geographic distribution, diversity, composition, structure and function of AMD microbial communities. In this study, we analyzed the geographic distribution of AMD microbial communities from twenty sites using restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes, and the results showed that AMD microbial communities were geographically distributed and had high variations among different sites. Then an AMD-specific microarray was used to further analyze nine AMD microbial communities, and showed that those nine AMD microbial communities had high variations measured by the number of detected genes, overlapping genes between samples, unique genes, and diversity indices. Statistical analyses indicated that the concentrations of Fe, S, Ca, Mg, Zn, Cu and pH had strong impacts on both phylogenetic and functional diversity, composition, and structure of AMD microbial communities. This study provides insights into our understanding of the geographic distribution, diversity, composition, structure and functional potential of AMD microbial communities and key environmental factors shaping them. This study investigated the geographic distribution of Acid Mine Drainages microbial communities using a 16S rRNA gene-based RFLP method and the diversity, composition and structure of AMD microbial communities phylogenetically and functionally using an AMD-specific microarray which contained 1,072 probes ( 571 related to 16S rRNA and 501 related to functional genes). The functional genes in the microarray were involved in carbon metabolism (158), nitrogen metabolism (72), sulfur metabolism (39), iron metabolism (68), DNA replication and repair (97), metal-resistance (27), membrane-relate gene (16), transposon (13) and IST sequence (11).
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.