Project description:The rapid pace of bacterial evolution enables organisms to adapt to the laboratory environment with repeated passage and thus diverge from naturally-occurring environmental (“wild”) strains. Distinguishing wild and laboratory strains is clearly important for biodefense and bioforensics; however, DNA sequence data alone has thus far not provided a clear signature, perhaps due to lack of understanding of how diverse genome changes lead to convergent phenotypes, difficulty in detecting certain types of mutations, or perhaps because some adaptive modifications are epigenetic. Monitoring protein abundance, a molecular measure of phenotype, can overcome some of these difficulties. We have assembled a collection of Yersinia pestis proteomics datasets from our own published and unpublished work, and from a proteomics data archive, and demonstrated that protein abundance data can clearly distinguish laboratory-adapted from wild. We developed a lasso logistic regression classifier that uses binary (presence/absence) or quantitative protein abundance measures to predict whether a sample is laboratory-adapted or wild that proved to be ~98% accurate, as judged by replicated 10-fold cross-validation. Protein features selected by the classifier accord well with our previous study of laboratory adaptation in Y. pestis. The input data was derived from a variety of unrelated experiments and contained significant confounding variables. We show that the classifier is robust with respect to these variables. The methodology is able to discover signatures for laboratory facility and culture medium that are largely independent of the signature of laboratory adaptation. Going beyond our previous laboratory evolution study, this work suggests that proteomic differences between laboratory-adapted and wild Y. pestis are general, potentially pointing to a process that could apply to other species as well. Additionally, we show that proteomics datasets (even archived data collected for different purposes) contain the information necessary to distinguish wild and laboratory samples. This work has clear applications in biomarker detection as well as biodefense.
2017-09-08 | PXD007254 | Pride
Project description:Glyptotendipes pallens
| PRJNA1140420 | ENA
Project description:Global diversity and distribution of mushroom-inhabiting bacteria
Project description:Laboratory strains of Saccharmoyces cerevisiae have been widely used as a model for studying eukaryotic cells and mapping the molecular mechanisms of many different human diseases. Industrial wine yeasts, on the other hand, have been selected over hundreds of years on the basis of their adaptation to stringent environmental conditions and the organoleptic properties they confer to wine. Here, we applied a two-factor design to study the response of a standard laboratory strain, CEN.PK.113-7D, and an industrial wine yeast-strain, EC1118, to growth temperature at 15°C and 30°C under 12 nitrogen-limited, anaerobic steady-state chemostat cultures. Physiological characterization revealed that growth temperature strongly impacted biomass yields in both strains. Moreover, we observed that the wine yeast is better adapted to mobilizing resources for biomass and that the laboratory yeast exhibited higher fermentation rates. To elucidate mechanistic differences controlling the growth temperature response and underlying adaptive mechanisms between strains, DNA microarrays and targeted metabolome analysis were used. We identified 1007 temperature dependent genes and 473 strain dependent genes. The transcriptional response was used to identify highly correlated subnetworks of significantly changing genes in metabolism. We show that temperature differences most strongly affect nitrogen metabolism and the heat shock response. Lack of STRE mediated gene induction, coupled with reduced trehalose levels, indicates a decreased general stress response at 15°C relative to 30°C. Between strains, differential responses are centred around sugar uptake, nitrogen metabolism and expression of genes related to organoleptic properties. Our study provides global insight into how growth temperature exerts a differential physiological and transcriptional response in laboratory and wine strains of S. cerevisiae.
Project description:While prion infections have been extensively characterized in the laboratory mouse, little is known regarding the molecular responses to prions in other rodents. To explore these responses and make comparisons, we generated a prion disease in the laboratory rat by successive passage of mouse RML prions. Here we describe the accumulation of prions and associated pathology in the rat and describe the transcriptional impact throughout prion disease. Comparative transcriptional profiling between laboratory mice and rats suggests that similar molecular processes are unfolding in response to prion infection. At the level of individual transcripts, however, variability exists between mice and rats and many genes deregulated in mouse scrapie are not affected in rats. Notwithstanding these differences, many transcriptome responses are conserved between mice and rats infected with scrapie. Our findings highlight the usefulness of comparative approaches to understanding neurodegeneration and prion diseases in particular. We Adapted RML Mouse Scrapie into Rats and measured the resulting gene expression changes in brain as a result of disease progression. Rats were infected by intracranial inoculation with prion isolates obtained by adaptation of mouse RML scrapie prions into rats. Brain samples were collected from third and fourth passage infected rats and age-matched controls at specified timepoints and gene expression profiles obtained. For each time point, 3 diseased and control brain samples were profiled.
Project description:Eulimnogammarus verrucosus is a Baikal endemic species inhabiting the lake's littoral. This species is adapted to low temperatures and it reproduces during fall-winter months. To capture aspects of adaptation to winter conditions in situ, we evaluated changes in the proteomes of E. verrucosus that were collected during the fall-winter months (September, November, December, and January) and early summer (June). Moreover, the aspects of reproduction of the cold-reproducing species were traced.