Oxidative stress is a major stress type observed in yeast bioprocesses, resulting in a decrease in yeast growth, viability, and productivity. Thus, robust yeast strains with increased resistance to oxidative stress are in highly demand by the industry. In addition, oxidative stress is also associated with aging and age-related complex conditions such as cancer and neurodegenerative diseases. Saccharomyces cerevisiae, as a model eukaryote, has been used to study these complex eukaryotic processes. However, the molecular mechanisms underlying oxidative stress responses and resistance are unclear. In this study, we have employed evolutionary engineering (also known as adaptive laboratory evolution – ALE) strategies to obtain an oxidative stress-resistant and genetically stable S. cerevisiae strain. Comparative physiological, transcriptomic, and genomic analyses of the evolved strain were then performed with respect to the reference strain. The results show that the oxidative stress-resistant evolved strain was also cross-resistant against other types of stressors, including heat, freeze-thaw, ethanol, cobalt, iron, and salt. It was also found to have higher levels of trehalose and glycogen production. Further, comparative transcriptomic analysis showed an upregulation of many genes associated with the stress response, transport, carbohydrate, lipid and cofactor metabolic processes, protein phosphorylation, cell wall organization, and biogenesis. Genes that were downregulated included those related to ribosome and RNA processing, nuclear transport, tRNA, and cell cycle. Whole genome re-sequencing analysis of the evolved strain identified mutations in genes related to the stress response, cell wall organization, carbohydrate metabolism/transport, which are in line with the physiological and transcriptomic results, and may give insight toward the complex molecular mechanisms of oxidative stress resistance.

Objective: Turkish Van cat is special cat breed in the world. The most important characteristics of the Turkish Van cats are the white and silky fur, and different eyes color. W locus of KIT gene was found to be an important gene for the white fur. However, there is not enough information about W locus of Turkish Van cats. The aim of this study was to determine the genotypic distribution of W locus alleles in Turkish Van cats and association between alelles and certain phenotypes. Material and Method: 48 Turkish Van cats bred in Van Yüzüncü Yıl University Van Cat Research and Application Center were selected for this study. DNA isolations were carried out from oral swaps and W locus genotyping of these cats was done by PCR. The Chi-square test was used to determine the association between the alleles and certain phenotypes. Results: It was shown that 41.67%, 22.92%, 18.75% and 16.67% of cats carried W/W, W/w+, w+/w+and W/ws, respectively. Frequencies of W locus alleles were found to be 61.45%, 30.21%, 8.33% for W, w+, ws, respectively. An association between detected genotypes and the phenotypic characters including eye color, head spotting, and hair length, could not be established. Conclusion: Turkish Van cats can carry white (W), white spotting (ws), and wild-type (w+) alleles in the W locus. No association between W locus alleles and eye color, head spotting, and fur length indicates other genetic variations should be addressed to understand genetical backround of the cats.