Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, Portugal.
Proteomics. 2012 Aug;12(14):2303-18. doi: 10.1002/pmic.201100457.
Zygosaccharomyces bailii is the most tolerant yeast species to acetic acid-induced toxicity, being able to grow in the presence of concentrations of this food preservative close to the legal limits. For this reason, Z. bailii is the most important microbial contaminant of acidic food products but the mechanisms behind this intrinsic resistance to acetic acid are very poorly characterized. To gain insights into the adaptive response and tolerance to acetic acid in Z. bailii, we explored an expression proteomics approach, based on quantitative 2DE, to identify alterations occurring in the protein content in response to sudden exposure or balanced growth in the presence of an inhibitory but nonlethal concentration of this weak acid. A coordinate increase in the content of proteins involved in cellular metabolism, in particular, in carbohydrate metabolism (Mdh1p, Aco1p, Cit1p, Idh2p, and Lpd1p) and energy generation (Atp1p and Atp2p), as well as in general and oxidative stress response (Sod2p, Dak2p, Omp2p) was registered. Results reinforce the concept that glucose and acetic acid are coconsumed in Z. bailii, with acetate being channeled into the tricarboxylic acid cycle. When acetic acid is the sole carbon source, results suggest the activation of gluconeogenic and pentose phosphate pathways, based on the increased content of several proteins of these pathways after glucose exhaustion.
酿酒酵母是耐乙酸毒性最强的酵母物种，能够在接近法定限量的这种食品防腐剂存在下生长。出于这个原因，酿酒酵母是酸性食品中最重要的微生物污染物，但这种对乙酸固有抗性的机制还没有得到很好的描述。为了深入了解酿酒酵母对乙酸的适应反应和耐受性，我们探索了一种基于定量 2-DE 的表达蛋白质组学方法，以鉴定在突然暴露或在抑制但非致死浓度的这种弱酸存在下平衡生长时，蛋白质含量发生的变化。细胞代谢，特别是碳水化合物代谢（Mdh1p、Aco1p、Cit1p、Idh2p 和 Lpd1p）和能量生成（Atp1p 和 Atp2p），以及一般和氧化应激反应（Sod2p、Dak2p、Omp2p）中的蛋白质含量协调增加。结果证实了这样的概念，即葡萄糖和乙酸在酿酒酵母中被共同消耗，乙酸被导入三羧酸循环。当乙酸是唯一的碳源时，根据葡萄糖耗尽后这些途径的几种蛋白质含量的增加，结果表明激活了糖异生和磷酸戊糖途径。
