Institute of Molecular Biosciences, University Graz, Graz, Austria.
FEMS Yeast Res. 2012 Nov;12(7):796-808. doi: 10.1111/j.1567-1364.2012.00830.x. Epub 2012 Jul 31.
Among the vast variety of Saccharomyces cerevisiae strains, the BY family is particularly important because the widely used deletion collections are based on this background. Here we demonstrate that some standard growth media recipes require substantial modifications to provide optimum growth conditions for auxotrophic BY strains and to avoid growth arrest before glucose is depleted. In addition to the essential supplements that are required to satisfy auxotrophic requirements, we found the four amino acids phenylalanine, glutamic acid, serine, and threonine to be indispensable for optimum growth, despite the fact that BY is 'prototrophic' for these amino acids. Interestingly, other widely used S. cerevisiae strains, such as strains of the CEN.PK family, are less sensitive to lack of the described supplements. Furthermore, we found that the concentration of inositol in yeast nitrogen base is too low to support fast proliferation of yeast cultures until glucose is exhausted. Depletion of inositol during exponential growth induces characteristic changes, namely a decrease in glucose uptake and maximum specific growth rate, increased cell size, reduced viability, and accumulation of lipid storage pools. Thus, several of the existing growth media recipes need to be revised to achieve optimum growth conditions for BY-derived strains.
在众多的酿酒酵母菌株中，BY 家族尤为重要，因为广泛使用的缺失株库都是基于这个背景。在这里，我们证明了一些标准的生长培养基配方需要进行大量的修改，以提供最佳的生长条件给营养缺陷型 BY 菌株，并避免在耗尽葡萄糖之前发生生长停滞。除了满足营养缺陷型需求所需的必需补充物之外，我们发现苯丙氨酸、谷氨酸、丝氨酸和苏氨酸这四种氨基酸对于最佳生长是必不可少的，尽管 BY 对这些氨基酸是“原养型”的。有趣的是，其他广泛使用的酿酒酵母菌株，如 CEN.PK 家族的菌株，对缺乏所描述的补充物的敏感性较低。此外，我们发现酵母氮碱基中的肌醇浓度太低，无法在耗尽葡萄糖之前支持酵母培养物的快速增殖。在指数生长期耗尽肌醇会诱导出特征性的变化，即葡萄糖摄取减少和最大比生长速率降低、细胞大小增加、活力降低以及脂类储存池的积累。因此，需要对现有的一些生长培养基配方进行修订，以实现 BY 衍生菌株的最佳生长条件。
