Publication details
A response of yeast cells to heat stress: cell viability and the stabilitz of cytoskeletal structures
| Authors | |
|---|---|
| Year of publication | 2000 |
| Type | Article in Periodical |
| Magazine / Source | Scripta medica |
| MU Faculty or unit | |
| Citation | |
| Field | Morphological specializations and cytology |
| Keywords | Saccharomyces cerevisiae; heat shock; Hsp104; actin; microtubules |
| Description | The cells of Saccharomyces cerevisiae were exposed to the effect of mild and lethal heat stress and their viability and changes in their microtubular and actin structures were studied. An increase in cultivation temperature from 25 C to 46 C (lethal heat shock, LHS) resulted, during 10 min, in a rapid decrease in cell viability. However, a mild increase in incubation temperature from 25 C to 37 C or 41 C (mild heat shock, MHS) induced cell tolerance to LHS and the cells were able to survive at 46 C for up to 30 min. A mild heat shock increased the level of Hsp104 in cells, as demonstrated by western blot analysis and indirect immunofluorescence microscopy. In cell exposed to LHS, immunofluorescence microscopy showed rapid degradation of both cytoplasmic and nuclear microtubules, but the spindle pole bodies (SPB) remained preserved. On the other hand, MHS did not produce microtubule degradation. Microtubules remained stable after the LHS that had been preceded by cell cultivation at 37 C. It is suggested that stress proteins induced by MHS were involved in maintaining microtubule stability. The actin cytoskeleton was very sensitive to heat shock and transfer of cells to both 37 C and 41 C resulted in disintegration of actin filaments and the spreading of actin dots from the bud to the whole cell surface. No stabilisation effect of stress proteins on actin structures was observed. Resistance to LHS was also induced by an osmotic shock in the presence of 1M KCl in culture medium. However, the production of stress proteins in response to osmotic shock was generally slower than to MHS because the cells became resistant to LHS only after being exposed to 1M KCl for 3 h. |
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