Monoterpenes are important aroma compounds in grape varieties such as Muscat, Gewürztraminer and Riesling, and are present as either odourless, glycosidically bound complexes or free aromatic monoterpenes. Commercial enzymes can be used to release the monoterpenes, but they commonly consist of crude extracts that often have unwanted and unpredictable side-effects on wine aroma. This project aims to address these problems by the expression and secretion of the Aspergillus awamoriα-l-arabinofuranosidase in combination with either the β-glucosidases from Saccharomycopsis fibuligera or from Aspergillus kawachii in the industrial yeast Saccharomyces cerevisiae VIN13. The concentration of five monoterpenes was monitored throughout alcoholic fermentation of Gewürztraminer grapes. The recombinant yeast strains that caused an early boost in the geraniol concentration led to a reduction in the final geraniol levels due to the downregulation of the sterol biosynthetic pathway. Monoterpene concentrations were also analysed 9 and 38 days after racking and the performance of the VB2 and VAB2 recombinant strains was similar, and in many cases, better than that of a commercial enzyme used in the same experiment. The results were backed by sensorial analysis, with the panel preferring the aroma of the wines produced by the VAB2 strain.
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http://dx.doi.org/10.1111/j.1567-1364.2010.00694.x | DOI Listing |
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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