Catalatic capacities in heat-shocked Euglena cells.
1. Various heat treatments were applied to the wild strain Z. Klebs. of Euglena gracilis. 2. Samples of cells were taken at day 1 of the culture at 26 degrees C in a 33 mM lactate medium, when the catalatic capacities of the catalase were highest. 3. They were either submitted to heat treatments (36 and 38 degrees C), or heat-shocks (40, 42 degrees C) or non-permissive heat stress (45 degrees C) for 15 min, 1 and 2 hr. 4. After a 2-hr 45 degrees C treatment the cells were unable to recover normal physiological functions. 5. Heat treatments between 36 and 38 degrees C decreased the catalatic capacities of cells, while heat-shocks at 40 and 42 degrees C strongly reinforced these capacities of hydrogen peroxide dismutation. 6. Having been heat-shocked at 42 degrees C for 2 hr, the cells became different from control cells: (a) after several months of culture, they displayed catalatic capacities increased by 65%; (b) they were able from now on to survive a 2 hr heat shock at 45 degrees C.
Edjlali
M
M
Laboratoire des Membranes Biologiques, UFR de Biologie et de Sciences de la Nature, Université Paris VII, France.
Laval-Martin
D
D
Calvayrac
R
R
D000818:Animals; D002374:Catalase / Q000378:metabolism; D002384:Catalysis; D005055:Euglena / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D013696:Temperature
D006360:Heat-Shock Proteins; D006861:Hydrogen Peroxide; D002374:Catalase