Hyperthermia Induced Changes in Viability and Proliferation of Tumorigenic and Nottumorigenic Cells

Abstract

Saccharomyces cerevisiae is a unicellular eukaryotic organism that often undergoes transition into the state of anhydrobiosis. During desiccation these cells lose the intracellular water, but still protect their structures from damages for successful recovery during rehydration. Aim: This study was performed to explore effects of cell preincubation in concentrated metabolizable carbon sources solutions on the resistance of S. cerevisiae to dehydrationrehydration. Materials and methods: Two S. cerevisiae strains were studied: #14 – semi-resistant, and #77 – very resistant to dehydration. The cells were incubated in 1 M solutions of glucose, lactose or glycerol for 3 h and desiccated at 30 oC for 21 h. Metabolic activity of the cells during rehydration was assayed by oxygen consumption test and fluorescence microscopy. Results: This study revealed that 1 M lactose-pretreated cells of #14 strain were consuming 70 % and 1 M glycerol-pretreated - 90% of the incubation medium dissolved oxygen. 1 M lactosepretreated cells of #77 strain were consuming 40 % of the dissolved oxygen, i.e., about 2-fold less than #14 strain, and 1 M glycerolpretreated - 50 % of the dissolved O2. The most intriguing result of this study is that after preincubation in the concentrated solutions of lactose or glycerol cells “switched” their phenotypes: #14 strain has become more resistant to dehydration than #77 one. However, such protection was not observed after preincubation in 1 M glucose.[...]