The species Saccharomyces cerevisiae includes natural strains, clinical isolates, and a large number of strains used in human activities. The aim of this work was to investigate how the adaptation to a broad range of ecological niches may have selectively shaped the yeast metabolic network to generate specific phenotypes. Using 72 S. cerevisiae strains collected from various sources, we provide, for the first time, a population-scale picture of the fermentative metabolic traits found in the S. cerevisiae species under wine making conditions. Considerable phenotypic variation was found suggesting that this yeast employs diverse metabolic strategies to face environmental constraints. Several groups of strains can be distinguished from the entire population on the basis of specific traits. Strains accustomed to growing in the presence of high sugar concentrations, such as wine yeasts and strains obtained from fruits, were able to achieve fermentation, whereas natural yeasts isolated from "poor-sugar" environments, such as oak trees or plants, were not. Commercial wine yeasts clearly appeared as a subset of vineyard isolates, and were mainly differentiated by their fermentative performances as well as their low acetate production. Overall, the emergence of the origin-dependent properties of the strains provides evidence for a phenotypic evolution driven by environmental constraints and/or human selection within S. cerevisiae.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174997 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0025147 | PLOS |
Nonsense-mediated decay (NMD) is a eukaryotic surveillance pathway that controls degradation of cytoplasmic transcripts with aberrant features. NMD-controlled RNA degradation acts to regulate a large fraction of the mRNA population. It has been implicated in cellular responses to infections and environmental stress, as well as in deregulation of tumor-promoting genes.
View Article and Find Full Text PDFJ Biol Chem
January 2025
Department of Biological Sciences, St. John's University, Queens, New York, USA. Electronic address:
One of the key events in DNA damage response (DDR) is activation of checkpoint kinases leading to activation of ribonucleotide reductase (RNR) and increased synthesis of deoxyribonucleotide triphosphates (dNTPs), required for DNA repair. Among other mechanisms, the activation of dNTP synthesis is driven by derepression of genes encoding RNR subunits RNR2, RNR3, and RNR4, following checkpoint activation and checkpoint kinase Dun1p-mediated phosphorylation and inactivation of transcriptional repressor Crt1p. We report here that in the absence of genotoxic stress during respiratory growth on nonfermentable carbon source acetate, inactivation of checkpoint kinases results in significant growth defect and alters transcriptional regulation of RNR2-4 genes and genes encoding enzymes of the tricarboxylic acid (TCA) and glyoxylate cycles and gluconeogenesis.
View Article and Find Full Text PDFmBio
January 2025
Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA.
Unlabelled: Pathogenic strains cause cholera using different mechanisms. O1 and O139 serogroup strains use the toxin-co-regulated pilus (TCP) and cholera toxin (CT) for intestinal colonization and to promote secretory diarrhea, while non-O1/non-O139 serogroup strains are typically non-toxigenic and use alternate virulence factors to cause a clinically similar disease. An O39 serogroup, TCP/CT-negative strain, named AM-19226, uses a type III secretion system (T3SS) to translocate more than 10 effector proteins into the host cell cytosol.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
Achieving targeted hypermutation of specific genomic sequences without affecting other regions remains a key challenge in continuous evolution. To address this, we evolved a T7 RNA polymerase (RNAP) mutant that synthesizes single-stranded DNA (ssDNA) instead of RNA in vivo, while still exclusively recognizing the T7 promoter. By increasing the error rate of the T7 RNAP mutant, it generates mutated ssDNA that recombines with homologous sequences in the genome, leading to targeted genomic hypermutation.
View Article and Find Full Text PDFScientificWorldJournal
January 2025
Department of Biochemistry and Biotechnology, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
Bioethanol production is one of the key alternatives for fossil fuel use due to climate change. The study seeks to upscale tailor-made onsite enzyme blends for the bioconversion of cassava peels to bioethanol in simultaneous saccharification and fermentation (SSF) process using cassava peels-degrading fungi. The starch and cellulose contents of peels were determined.
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