Project description:The rise of dark (melanic) forms of many species of moth in heavily coal-polluted areas of nineteenth- and twentieth-century Britain, and their post-1970s fall, point to a common selective pressure (camouflage against bird predators) acting at the community level. The extent to which this convergent phenotypic response relied on similar genetic and developmental mechanisms is unknown. We examine this problem by testing the hypothesis that the locus controlling melanism in Phigalia pilosaria and Odontopera bidentata, two species of geometrid moth that showed strong associations between melanism and coal pollution, is the same as that controlling melanism in Biston betularia, previously identified as the gene cortex. Comparative linkage mapping using family material supports the hypothesis for both species, indicating a deeply conserved developmental mechanism for melanism involving cortex. However, in contrast to the strong selective sweep signature seen in British B. betularia, no significant association was detected between cortex-region markers and melanic morphs in wild-caught samples of P. pilosaria and O. bidentata, implying much older, or diverse, origins of melanic morph alleles in these latter species.
Project description:Our study involves a transcriptomic approach to the analysis of industrial yeast metabolism. Historically, among the hundreds of yeast species, Saccharomyces cerevisiae has played an important role in scientific investigations and industrial applications, and it is universally acknowledged as one of the model systems for eukaryotic organisms. Yeast is also an important component of the wine fermentation process and determines various attributes of the final product. Our research takes a holistic approach to the improvement of industrial yeast strains by integrating large data sets from various yeast strains during fermentation. This means that analysis can be done in such a way as to co-evaluate several parameters simultaneously to identify points of interest and target genes for metabolic engineering. Eventually we hope to construct an accurate information matrix and a more complete cellular map for the fermenting yeast. This will enable accurate model-building for industrial yeast and facilitated the design of intelligent yeast improvement strategies which can be applied via traditional avenues of molecular biology. Experiment Overall Design: Five different Saccharomyces cerevisiae strains used in industrial winemaking processes were used in synthetic must (MS300) fermentations. All fermentations were carried out in triplicate, so each sample is represented by three completely independent biological repeats. Samples for microarray analysis were taken at three different time points during fermentation, representative of the exponential (day2), early stationary (day5) and late stationary (day14) growth stages.
Project description:Our study involves a transcriptomic approach to the analysis of industrial yeast metabolism. Historically, among the hundreds of yeast species, Saccharomyces cerevisiae has played an important role in scientific investigations and industrial applications, and it is universally acknowledged as one of the model systems for eukaryotic organisms. Yeast is also an important component of the wine fermentation process and determines various attributes of the final product. Our research takes a holistic approach to the improvement of industrial yeast strains by integrating large data sets from various yeast strains during fermentation. This means that analysis can be done in such a way as to co-evaluate several parameters simultaneously to identify points of interest and target genes for metabolic engineering. Eventually we hope to construct an accurate information matrix and a more complete cellular map for the fermenting yeast. This will enable accurate model-building for industrial yeast and facilitated the design of intelligent yeast improvement strategies which can be applied via traditional avenues of molecular biology.
Project description:The environmental stresses and inhibitors encounted by Saccharomyces cerevisiae strains are main limiting factors in bioethanol fermentation. Investigation of the molecular mechanisms underlying the stresses-related phenotypes diversities within and between S. cerevisiae populations could guide the construction of yeast strains with improved stresses tolerance and fermentation performances. Here, we explored the genetic characteristics of the bioethanol S. cerevisiae strains, and elucidated the genetic variations correlated with its advantaged traits (higher ethanol yield under sever conditions and better tolerance to multiple stresses compared to an S288c derived laboratory strain BYZ1). Firstly, pulse-field gel electrophoresis combined with array-comparative genomic hybridization was used to compare the genome structure of industrial strains and the laboratory strain BYZ1.
Project description:In this study, we investigated the impact of industrial antifoam agents on the physiology and transcriptome of the industrial ethanol Saccharomyces cerevisiae strain CAT-1. We showed that under industrial molasses fermentations similar to the ones used for ethanol production in Brazil, antifoam agents had detrimental effects on productivity, viability and lead to increased stress responses in yeast.
Project description:Schizosaccharomyces pombe is a model unicellular eukaryote with ties to the basic research, oenology and industrial biotechnology sectors. While most investigations into S. pombe cell biology utilize Leupold’s 972h- laboratory strain background, recent studies have described a wealth of genetic and phenotypic diversity within wild populations of S. pombe including stress resistance phenotypes which may be of interest to industry. Here we describe the genomic and transcriptomic characterization of Wilmar-P, an S. pombe isolate used for bioethanol production from sugarcane molasses at industrial scale. Novel sequences present in Wilmar-P but not in the laboratory S. pombe genome included multiple coding sequences with near-perfect nucleotide identity to Schizosaccharomyces octosporus sequences. Wilmar-P also contained a ~100kb duplication in the right arm of chromosome III, a region harboring ght5+, the predominant hexose transporter encoding gene. Transcriptomic analysis of Wilmar-P grown in molasses revealed strong downregulation of core environmental stress response genes and upregulation of hexose transporters and drug efflux pumps compared to laboratory S. pombe. Finally, examination of the regulatory network of Scr1, which is involved in the regulation of several genes differentially expressed on molasses revealed expanded binding of this transcription factor in Wilmar-P compared to laboratory S. pombe in the molasses condition. Together our results point to both genomic plasticity and transcriptomic adaptation as mechanisms driving phenotypic adaptation of Wilmar-P to the molasses environment and therefore adds to our understanding of genetic diversity within industrial fission yeast strains and the capacity of this strain for commercial scale bioethanol production.
Project description:Lactobacillus rhamnosus GG has become one of the most widely marketed and studied probiotic strains. Several genes important for probiotic function have been identified, including the spaCBA-srtC1 gene cluster encoding pili, which have been shown to be important for certain of its probiotic properties. The spaCBA-srtC1 gene cluster has been reported to be unstable in L. rhamnosus GG isolated from liquid dairy products and therefore the present study examined the L. rhamnosus GG genome stability throughout an industrial production process from the original deposit to the freeze-dried products including intermediate fermentations and single colony isolates prepared from these samples. The results showed that the original deposit was identical to the reference ATCC and that the genome sequence stayed fully intact throughout the production process. No SNPs or larger genomic changes occurred in any of the samples throughout the production process and the spaCBA-srtC1 gene locus was fully conserved and intact in all 31 samples examined. In addition, phenotypic expression of pili was demonstrated using immune-gold labelling EM. The images showed that pili production was preserved throughout the production process and that the number of pili were consistent in all batches. The present study extends the scope of previous findings to an industrial setting and shows that the region around the spaCBA-srtC1 cluster exhibits high stability in L. rhamnosus GG in an industrial production process.