Publication details
Odpověď kvasinkových buněk na teplotní šok: vliv osmotického, radiačního a mírného teplotního šoku
| Title in English | A response of yeast cells to heat shock: the effect of osmotic, radiation and mild heat stress |
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| Authors | |
| Year of publication | 2000 |
| Type | Article in Proceedings |
| Conference | Tomáškovy dny 2000 |
| MU Faculty or unit | |
| Citation | |
| Field | Microbiology, virology |
| Description | On the model of yeast Saccharomyces cerevisiae CCY 21-4-59 the effects of heat, osmotic and radiation stresses on cells exposed to the lethal heat shock were studied Thermoresistance or thermosensitivity of cells was detected by their ability to form colonies (CFU) at 25 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. It was found that a 30 min preincubation of cells at 37 or 41 degrees C (referred here as a mild heat stress) lead to the increase of their resistance to the 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. Accumulation of Hsp104 was detected also by indirect immunofluorescence technique in cytoplasm of cells after mild heat stress. 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. 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 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. Similarly, microtubules from mild stressed cells remained stable after the transfer of cells to 0 degrees C, while in controls this cooling lead to the microtubule disintegration. Both osmotic and radiation stresses caused a rapid degradation of microtubules. These re-appear within 2 to 3 hr of incubation and remained then stable at 46 degrees C. Actin structures (cables and patches) were more sensitive: actin cables disappeared and polar localisation of actin patches were disrupted even in mild stressed cells. It can be concluded that the stress proteins, including Hsp104, formed under condition of mild stress, take part in the maintenance cell integrity during heat shock. |
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