Saccharomyces cerevisiae wine strains can develop stuck or sluggish fermentations when nutrients are scarce or suboptimal. Nutrient sensing and signaling pathways, such as PKA, TORC1 and Snf1, work coordinately to adapt growth and metabolism to the amount and balance of the different nutrients in the medium. This has been exhaustively studied in laboratory strains of S. cerevisiae and laboratory media, but much less under industrial conditions. Inhibitors of such pathways, like rapamycin or 2-deoxyglucose, failed to discriminate between commercial wine yeast strains with different nutritional requirements, but evidenced genetic variability among industrial isolates, and between laboratory and commercial strains. Most signaling pathways involve events of protein phosphorylation that can be followed as markers of their activity. The main pathway to promote growth in the presence of nitrogen, the TORC1 pathway, measured by the phosphorylation of Rps6 and Par32, proved active at the very start of fermentation, mainly on day 1, and ceased soon afterward, even before cellular growth stopped. Transcription factor Gln3, which activates genes subject to nitrogen catabolite repression, was also active for the first hours, even when ammonium and amino acids were still present in media. Snf1 kinase was activated only when glucose was exhausted under laboratory conditions, but was active from early fermentation stages. The same results were generally obtained when nitrogen was limiting, which indicates a unique pathway activation pattern in winemaking. As PKA remained active throughout fermentation, it could be the central pathway that controls others, provided sugars are present. Wine fermentation is a distinct environmental situation from growth in laboratory media in molecular terms. The mechanisms involved in glucose and nitrogen repression respond differently under winemaking conditions.

中文翻译：

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酿酒酵母的营养信号传导途径在酿酒过程中显示出意外的早期激活模式。

当营养缺乏或不理想时，酿酒酵母酒株会发酵或停滞发酵。营养感应和信号通路（例如PKA，TORC1和Snf1）协同工作，以使生长和代谢适应培养基中不同营养物质的数量和平衡。在酿酒酵母和实验室培养基的实验室菌株中已对此进行了详尽的研究，但在工业条件下却很少。雷帕霉素或2-脱氧葡萄糖等途径的抑制剂未能区分具有不同营养需求的商业葡萄酒酵母菌株，但在工业分离株之间以及实验室菌株和商业菌株之间证明了遗传变异性。大多数信号通路都涉及蛋白质磷酸化事件，可以作为其活性的标志。通过Rps6和Par32的磷酸化测量，TORC1途径是在氮存在下促进生长的主要途径，在发酵的一开始（主要是在第1天）就被证明是有活性的，此后不久就停止了，甚至在细胞生长停止之前。转录因子Gln3可以激活受氮分解代谢物阻抑的基因，即使在培养基中仍存在铵和氨基酸的情况下，其最初几个小时仍具有活性。仅在实验室条件下耗尽葡萄糖时，Snf1激酶才被激活，但从早期发酵阶段开始就具有活性。当氮受到限制时，通常可获得相同的结果，这表明酿酒中独特的途径活化方式。由于PKA在整个发酵过程中仍然保持活性，因此如果存在糖，它可能是控制其他途径的主要途径。从分子的角度来看，葡萄酒发酵与实验室培养基的生长是不同的环境状况。在酿酒条件下，葡萄糖和氮的抑制机制不同。