Research Information System
6th International Congress on Applied Biological Sciences, Adana, Turkey, 8 - 09 December 2021, pp.16-17
The yeast Saccharomyces cerevisiae accumulates two
types of glucose stores trehalose and glycogen. Glycogen is a multi-branched
polysaccharide and trehalose is a non-reducing disaccharide. The levels of
these storage carbohydrates change during the incubation of cells to prolonged
starvation or stress conditions. The trehalose and glycogen content of cells is
regulated by synthesis and degradation enzymes depending on the physiological
state of yeast cells. The genes involved in the regulation of reserve
carbohydrates are controlled by several signaling pathways. TOR pathway is
regulated depending on the quantity and quality of nitrogen in S. cerevisiae. SIR2 encodes an NAD+-dependent deacetylase enzyme
involved in chromatin silencing and decreases yeast lifespan.
The expression of the yeast SIR2 gene
is increased in oxidative stress or intracellular stress conditions The decrease in Sir2 protein activity
indirectly causes an increase in intracellular trehalose accumulation. In our research, the reserve carbohydrate accumulation of wild type and Δsir2 yeast cells was determined under nitrogen starvation
condition. Ammonium
sulfate and proline were used as strong and weak nitrogen sources,
respectively. The
results showed that the glycogen accumulation of wild-type and Δsir2 yeast cells was greater than the
accumulation of trehalose under both normal and starvation conditions. In
addition, it was observed that the amount of reserve carbohydrate accumulated
by mutant yeast cells in nitrogen starvation was 2-3 times higher than that of
wild type yeast cells. These results show that Sir2 protein has a direct or
indirect role in the regulation of genes involved in storage carbohydrate
metabolism in both stress and normal growth conditions.