Publication details
Buněčný stres a stabilita cytoskeletu
| Title in English | Cell stress and stability of cytoskeleton |
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| Authors | |
| Year of publication | 2000 |
| Type | Article in Proceedings |
| Conference | VIII. Cytoskeletání klub |
| MU Faculty or unit | |
| Citation | |
| Field | Microbiology, virology |
| Description | On the model of yeast Saccharomyces cerevisiae the effects of heat, osmotic and radiation stresses on cells exposed to the lethal heat shock were studied. During these stresses adaptive synthesis of Hsp104 was detected and behavior of the microtubules and actin was followed.. Thermoresistance of cells was detected by their ability to form colonies (CFU). It was found that a short incubation of cells in higher temperature ( 37 degreesC or 41 degrees C - mild heat stress) lead to the increase of their resistance to the lethal heat shock 46 degrees C. After the transfer from 25 to 46 degrees C most of cells lost their viability during 10 min of incubation and this temperature was then referred as lethal heat shock. Western blotting technique + ECL revealed that during mild heat stress the concentration of Hsp104 in cells increased, while in controls only traces of this protein were detected. The Hsp104 synthesis was apparently adaptive, because cykloheximid present during mild heat stress effectively prevented the increase of cell thermoresistance. Increased amount of HSP104 was detected also by using indirect imunofluorescence method in cytoplasma in cells after mild heat shock. In control cells the lethal heat shock 46 degrees C caused rapid disintegration of spindle and cytoplasmic microtubules leaving preserved only point fluorescence of spindle pole bodies. Mild heat stress (37-41degrees C) did not lead to the degradation of microtubules and, surprisingly, the microtubules from these pre-treated cells remained stable even after the transfer of cells to 46 degrees C. Stress proteins, which are generated at higher incubation temperature, evidently participate on the stability of microtubules. Actin structures (cables and patches) were more sensitive: actin cables disappeared and polar localisation of actin patches were disrupted even in mild stressed cells. We did not observed any stabilizing effect of stress proteins on actin. We found that the resistance to heat shock 46 degrees C could be induced also by previous osmotic shock (1M KCl) or short UV radiation. However, the stress proteins seemed to form slowlier, because the cells became thermoresistant only after 3 hours adaptation following heat shock application. Both, osmotic and radiation shock, causes quick degradation of microtubules and aktin stuctures. |
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