摘要
During the industrial production of active dry yeast (ADY) and its subsequent use in winemaking, the yeast cell is subjected to drastic environmental changes that force it to undergo extensive metabolic modifications and changes in gene expression. In this study, we describe the use of real-time reverse transcription–polymerase chain reaction (RT–PCR) to monitor gene expression in ADY Saccharomyces cerevisiae during rehydration in different media.
We used three statistical approaches to investigate the expression stability of eight potential reference genes during the rehydration process. The reference system thus obtained was used to normalize the expression values of three genes codifying for the ammonium transporters—MEP1, MEP2, and MEP3—and two genes involved in the osmotic response—SIP18 and GPD1.
The results suggested that for the target genes tested, the yeast reacted immediately to rehydration only when a fermentable carbon source was present in the medium. Furthermore, MEP2 expression was modulated by the ammonium concentration, indicating that nitrogen catabolite repression (NCR) is active during the rehydration phase.
摘要译文
在工业生产活性干酵母（ADY）及其后用于酿酒的过程中，酵母细胞受到剧烈的环境变化，迫使其经历广泛的代谢修饰和基因表达的变化。在这个研究中，我们描述了使用实时逆转录聚合酶链反应（RT-PCR）来监测不同培养基中再水合过程中ADY酿酒酵母中的基因表达。我们使用三种统计方法来研究8个潜在参考基因在补液过程中的表达稳定性。使用如此获得的参照系来归一化编码铵转运体-MEP1，MEP2的三个基因的表达值，和MEP3-以及两个参与渗透反应的基因 - SIP18和GPD1。结果表明，对于测试的靶基因，只有当培养基中存在可发酵的碳源时，酵母立即反应才能再水化。此外，MEP2表达受铵浓度调节，表明氮代谢产物阻遏（NCR）在再水合阶段期间是活跃的。
Enrico Vaudano; Antonella Costantini; Manuela Cersosimo; Vincenzo Del Prete; Emilia Garcia-Moruno. Application of real-time RT–PCR to study gene expression in active dry yeast (ADY) during the rehydration phase[J]. International Journal of Food Microbiology, 2009,129(1): 30–36