[S3-1] 酵母の [GAR+] 化機構の解明に向けて
Saccharomyces cerevisiae, especially the strains used for alcohol fermentation, repress the expression of genes for the utilization of non-glucose carbon sources in the presence of glucose. This well-known trait of yeast, glucose repression, was thought to result in the rapid elevation of ethanol level, and prevention of the growth of other bacterial cells during alcohol fermentation. Recent study revealed that a protein-based epigenetic element, [GAR+], allows yeast cells to circumvent the glucose repression and use multiple carbon sources in the presence of glucose. It was also demonstrated that the emergence ratio of [GAR+] was elevated in the presence of lactic acid bacterial species. In the traditional kimoto-type sake brewing, yeast cells are grown in a starter mash in the presence of lactic acid bacteria. It was thought that the number of [GAR+] cells increased in the kimoto-type sake brewing and affect the quality of end-products. In this study, the presence of [GAR+] cells was examined in the starter mash provided from sake breweries. The growth conditions which increase the ratio of [GAR+] cells were also evaluated by in vitro growth assay.