Morphometric and biochemical analysis of yeast cells under low temperature storage

Abstract

The aim of the research is to measure thiol compounds as well as glycogen content in yeast cells of different sizes during long-term storage at low temperature. The size, SH-groups and glycogen content changes in the S. cerevisiae cells were studied over the period of 35 days storage at 0±5 °C. The new morphometric method used has showed that the total amount of cells and number of large cells (7-8 × 12-15 µm) remained unchanged when compared with control under model conditions; the number of budding yeasts decreased 4 times, and the number of dead cells increased 2 times during the storage period. The number of middle size cells (5-7 × 10-12 µm) decreased 1.2 times, while the number of small cells (4-5 × 7-9 µm) increased 9.5 times. Under the same conditions the quantity of low molecular SH-groups increased 2 times, while protein-containing SH-groups dropped down by 31%. The content of glycogen decreased 1.2 times. The results elaborated revealed that generally yeasts under unfavorable conditions lose the deposition nutrients such as glycogen and store up the adaptive SH-containing substances. The cells of a large size probably have more high adaptation capacity to long-term storage at low temperature and in the absence of a nutrient medium. The rising amount of small cells and of low molecular SH-groups evidently indicates the development of adaptation state in the yeast population. Future investigations have to find out the range correlations between morphologic parameters of yeast cells and the content of biochemical substances.