Project description:Monitoring microbial communities can aid in understanding the state of these habitats. Environmental DNA (eDNA) techniques provide efficient and comprehensive monitoring by capturing broader diversity. Besides structural profiling, eDNA methods allow the study of functional profiles, encompassing the genes within the microbial community. In this study, three methodologies were compared for functional profiling of microbial communities in estuarine and coastal sites in the Bay of Biscay. The methodologies included inference from 16S metabarcoding data using Tax4Fun, GeoChip microarrays, and shotgun metagenomics.
Project description:Chromophobic renal cell carcinomas (chRCC) typically have a hypodiploid genome, including a loss of chromosomes 1, 2, 6, 10, 13, 17 and 21, but few cases in the literature showed a gain of many chromosomes, suggesting a tetraploidy. The detection of this characteristic performed by comparative genomic hybridization (CGH-array), is very helpful for the diagnosis. To better characterize the phenomenon of tetraploidization and to explore the consequence and the difficulties of its detection, we studied a subset of 26 chRCC, including five cases of tetraploid chRCC, for which complementary analyses were performed. Our main objective was to determine whether these four cases displayed chromosomal losses typical of chRCC whitin a near-polyploid genome instead within a near-diploid one. We discuss the hazards and limitations of different molecular methods in the detection of polyploidization and its potential clinical consequences. In our study we show that this phenomenon of tetraploidization affects about 19% of chRCC and that is probably overlooked using standard molecular methods. The potential clinical consequences of this phenomenon are not identified yet.
2019-11-15 | GSE140390 | GEO
Project description:Optimising species detection probability and sampling effort in lake fish eDNA surveys
Project description:miRNAs are excellent tumor biomarkers because of their cell-type specificity and abundance. However, many miRNA detection methods, such as real-time (RT)-PCR, obliterate valuable visuospatial information in tissue samples. To enable miRNA visualization in formalin-fixed paraffin-embedded (FFPE) tissues, we developed multicolor miRNA fluorescence in situ hybridization (FISH). For proof-of-concept, we differentiated two skin tumors, namely Basal cell carcinoma (BCC) and Merkel cell carcinoma (MCC), with overlapping histologic features but distinct cellular origins. Using sequencing-based miRNA profiling and discriminant analysis, we identified tumor-specific miRNAs (miR-205 and miR-375) in BCC and MCC respectively. We addressed three major shortcomings in miRNA FISH, identifying optimal conditions for miRNA fixation and rRNA retention using model compounds and HPLC analyses, enhancing signal amplification and detection by increasing probe-hapten linker lengths, and improving probe specificity using shortened probes with minimal rRNA sequence complementarity. We validated our method on 4 BCC and 12 MCC tumors. Amplified miR-205 and miR-375 signals were normalized against directly detectable reference rRNA signals. Tumors were classified using pre-defined cut-off values; all were correctly identified in blinded analysis. We established a reliable miRNA FISH technique for parallel visualization of differentially expressed miRNAs in FFPE tumor tissues