Project description:Metagenomic sequencing of bacteria inhabititng the chemocline of Lake Cadagno, as well as an phototrophic sulfur-oxidizing enrichment culture established from the chemocline
Project description:Anthropogenic activities such as urbanization and agriculture can potentially pose a threat to neighboring freshwaters through nitrate and phosphorous contamination, which over time may lead to lake eutrophication. In such nitrogen-polluted environments, oxygen is depleted, and plants die and decompose. This enhances denitrifying microbes that respire under hypoxic/anoxic conditions by reducing nitrate instead of molecular oxygen and using plant remnants (lignocellulose) as carbon source. Microbial lignocellulose degradation has been well-studied for both aerobic- and anaerobic conditions; however, its degradation during denitrification remains largely unknown. Here we have applied a combination of gas kinetics and meta-omics techniques to enrich and analyze microbial communities from 10 eutrophic lakes to identify a set of core microbial metagenome-assembled genomes (MAGs) present in all the eutrophic lakes. We have further investigated their strategies and enzyme profiles for degrading lignocellulose under denitrifying conditions. We identified Pseudomonadota, Bacteroidota, Verrucomicrobiota, and Actinomycetota as the most abundant phyla and they were present in enrichments from all eutrophic lakes having a key role in denitrification and fermentation. Lignocellulose degradation was, however, dominated by species outside the core microbiome, i.e., there were differing key degraders between lakes, suggesting some level of lake-specialization. Among these we observed potential respiratory DNRA pathways, and they expressed a broad range of CAZymes targeting the various lignocellulose subfractions. Interestingly, many of the detected MAGs contained NO dismutases, enzymes postulated to convert NO to molecular oxygen and dinitrogen gas.
Project description:Raw RNA sequences of purple sulfur bacterium Chromatium okenii strain LaCa isolated form the chemocline of meromictic Lake Cadagno. Study involves the investigation of the differences in the gene expression level between two different times of the summer season (July vs September), during the day and at night.
Project description:Lake trout are used as bioindicators for toxics exposure in the Great Lakes ecosystem. However, there is no knowledge about lake trout proteome. Here we performed the first lake trout (Salvelinus namaycush) liver proteomics and searched the databases against (NCBI and UniProtKB) Salvelinus, Salmonidae, Actinopterygii and the more distant Danio rerio. In the NCBI search, we identified 4371 proteins in 1252 clusters. From these proteins, we found 2175 proteins in Actinopterygii 1253 in Salmonidae, 69 in Salvelinus and 901 in Danio rerio NCBI searches. In the UniProtKB search, we identified 2630 proteins in 1100 clusters. From these proteins, we found 317 in Actinopterygii, 1653 in Salmonidae, 37 in Salvelinus and 666 in Danio rerio UniProtKB searches. A similar outcome was also obtained from a technical replicate experiment. A large number of lake trout liver proteins were not in any Salvelinus databases, suggesting that lake trout liver proteins have homologues to some proteins from the Salmonidae family and Actinopterygii class, as well as to the species Danio rerio, a more highly studied Cypriniformes fish. Therefore, our study not only builds the first comprehensive lake trout protein database, but also establishes protein homology-based evolutionary relationships between the fish within their family and class, as well as distant-related fish (lake trout and zebrafish). In addition, this study opens the possibility of identifying evolutionary relationships (i.e. adaptive mutations) between various groups (i.e. zebrafish, Salmonidae, Salvelinus and lake trout) through evolutionary proteomics
Project description:Deep Lake is a hypersaline system in Antarctica (68°33’36.8S, 78°11’48.7E) that is so saline it remains liquid at –20°C (DeMaere et al 2013). The lake is dominated by haloarchaea, comprising a low-complexity community that differs greatly to warm-hot latitude hypersaline systems, is hierarchical structured, and supports a high level of intergenera gene exchange. Metaproteomics was performed on biomass that was collected in the austral summer of 2008 by sequential size fractionation (20 – 3 µm, 3 – 0.8 µm, 0.8 – 0.1 µm). The data were integrated to obtain a systems level view of the active host-virus interactions occurring in this novel aquatic Antarctic system. DeMaere MZ, Williams TJ, Allen MA, Brown MV, Gibson JA, Rich J, Lauro FM, Dyall-Smith M, Davenport KW, Woyke T, Kyrpides NC, Tringe SG, Cavicchioli R (2013) High level of intergenera gene exchange shapes the evolution of haloarchaea in an isolated Antarctic lake. Proc Natl Acad Sci USA 110: 16939-16944