Project description:Despite the discovery of Mycobacterium tuberculosis (Mtb) more than 130 years ago, Mtb physiology and the mechanisms of virulence are still not fully understood. The objective of this study was to compare and characterize the differentially abundant protein profiles of modern, pre-modern and ancient Mtb lineages. Using a comprehensive analysis of the proteome of Mtb lineages 3, 4, 5 and 7, unique and shared proteomic signatures in these modern, pre-modern and ancient Mtb lineages were delineated. Main proteomic findings were verified by using immunoblotting. In addition, analysis of multiple genome alignment of all lineages was performed using Geneious Prime software. Label-free peptide quantification of whole cells from Mtb lineage 3, 4, 5 and 7 yielded 38,346 unique peptides derived from 3092 proteins, representing 77% coverage of the predicted Mtb proteome. Mtb lineage-specific differential abundances was observed for 539 proteins. Lineage 7 exhibited a markedly reduced abundance of proteins involved in DNA repair, type VII ESX-3 and ESX-1 secretion systems, lipid metabolism and inorganic phosphate uptake, and an increased abundance of proteins involved in alternative pathways of the TCA cycle and the CRISPR/Cas system as compared to the other lineages. Lineages 3 and 4 exhibited a higher abundance of proteins involved in virulence, DNA repair, drug resistance and other metabolic pathways. The high throughput analysis of Mtb proteome by super resolution massspectrometry provided an insight into the differential expression of proteins between Mtb lineages 3, 4, 5 and 7 that may explain the slow growth and reduced virulence of lineage 7, as well as metabolic flexibility and the ability to survive under adverse growth conditions.
Project description:The ancient preserved molecules in bones offer the opportunity to gain a better knowledge on the biological past. In recent years, bones proteomics has become an attractive method to study extinct species and phylogenetic evolution as an alternative to DNA analysis which is limited by DNA amplification present in ancient samples and its contamination. The analysis of fossils must consume a low quantity of material to avoid damaging the samples. Another difficulty is the absence of genomic data for most of the extinct species. This study applied a proteomic methodology to mammalian bones of 130,000 / 120,000 years old from the last Chibanian and the earlier Upper Pleistocene site of Waziers (France). The presence of lithic artefacts and the traces of butchery observed on the bones indicate the presence of Neanderthal Man on this site. Starting from 5 milligram samples, our results show that most detected peptides match collagen I alpha 1 and alpha 2 proteins with a sequence coverage up to 60 %. Using sequence homology with modern sequences, a biological classification was successfully achieved. Each bone taxonomic rank by proteomics was consistent with the existing osteomorphological studies and palaeoenvironmental and palaeodietary data.
Project description:Characterization of Middle Pleistocene rhinoceros proteins and the phylogenetic relationships between extinct and extanct rhinoceros was investigated by obtaining ancient protein data for two extinct rhinoceros genera (Coelodonta antiquitatis and Stephanorhinus sp.).
