Department of Food, Environmental and Nutritional Sciences, University of Milan, Milan, Italy.
Food Microbiol. 2013 Dec;36(2):316-9. doi: 10.1016/j.fm.2013.06.011. Epub 2013 Jul 6.
Dekkera bruxellensis is mainly associated with lambic beer fermentation and wine production and may contribute in a positive or negative manner to the flavor development. This yeast is able to produce phenolic compounds, such as 4-ethylguaiacol and 4-ethylphenol which could spoil the wine, depending on their concentration. In this work we have investigated how this yeast responds when exposed to conditions causing osmotic stress, as high sorbitol or salt concentrations. We observed that osmotic stress determined the production and accumulation of intracellular glycerol, and the expression of NADH-dependent glycerol-3-phosphate dehydrogenase (GPD) activity was elevated. The involvement of the HOG MAPK pathway in response to this stress condition was also investigated. We show that in D. bruxellensis Hog1 protein is activated by phosphorylation under hyperosmotic conditions, highlighting the conserved role of HOG MAP kinase signaling pathway in the osmotic stress response. Gene Accession numbers in GenBank: DbHOG1: JX65361, DbSTL1: JX965362.
德克氏酵母主要与拉比克啤酒发酵和葡萄酒生产有关，并可能对风味的发展产生积极或消极的影响。这种酵母能够产生酚类化合物，如 4-乙基愈创木酚和 4-乙基苯酚，这取决于它们的浓度，可能会使葡萄酒变质。在这项工作中，我们研究了这种酵母在受到高山梨糖醇或盐浓度等渗透胁迫条件下的反应。我们观察到，渗透胁迫决定了细胞内甘油的产生和积累，NADH 依赖的甘油-3-磷酸脱氢酶（GPD）活性的表达也升高了。我们还研究了 HOG MAPK 途径对这种应激条件的反应。我们表明，在德克氏酵母中，Hog1 蛋白在高渗条件下通过磷酸化被激活，突出了 HOG MAP 激酶信号通路在渗透胁迫反应中的保守作用。GenBank 中的基因访问号：DbHOG1: JX65361，DbSTL1: JX965362。
