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Glycogen is a highly branched polyglucan utilized as a carbohydrate reserve in major living systems. Industrially, it is used as a prebiotic and in the nanoencapsulation of drugs and nutraceuticals. In this study, optimal fermentation conditions enabling the highest glycogen accumulation in Saccharomyces cerevisiae were experimentally evaluated for possible mass production. Production efficiency was assessed by comparing specific growth rates, specific glycogen production rates, and glycogen yields under each condition. The results demonstrated that fermentation at 30 °C with an aeration rate of 3 vvm using a medium containing 120 g/L glucose without ethanol was optimal for robust cell growth and maximum glycogen yield. Additionally, a rich medium outperformed a minimally defined medium, and a single sugar carbon source, as opposed to mixed sugars, resulted in significantly higher cell growth and glycogen yields (p < 0.05). The optimized fermentation parameters enabled a glycogen production rate of up to 0.232 ± 0.012 g-glycogen/g-cell/h and a glycogen yield of 0.603 ± 0.006 g-glycogen/g-glucose. These results provide meaningful information for future studies and/or large-scale glycogen production using S. cerevisiae. [ABSTRACT FROM AUTHOR]

During meiosis I, programmed DNA double-strand breaks (DSBs) occur to promote chromosome pairing and recombination between homologs. In Saccharomyces cerevisiae , Mec1 and Tel1, the orthologs of human ATR and ATM, respectively, regulate events upstream of the cell cycle checkpoint to initiate DNA repair. Tel1 ATM and Mec1 ATR are required for phosphorylating various meiotic proteins during recombination. This study aimed to investigate the role of Tel1 ATM and Mec1 ATR in meiotic prophase via physical analysis of recombination. Tel1 ATM cooperated with Mec1 ATR to mediate DSB-to-single end invasion transition, but negatively regulated DSB formation. Furthermore, Mec1 ATR was required for the formation of interhomolog joint molecules from early prophase, thus establishing a recombination partner choice. Moreover, Mec1 ATR specifically promoted crossover-fated DSB repair. Together, these results suggest that Tel1 ATM and Mec1 ATR function redundantly or independently in all post-DSB stages.