ALTERATIONS INDUCED BY HIGH-TEMPERATURE IN EUGLENA-GRACILIS IN THE RECOVERY PERIOD

In the recovery period - 48 hours after heat treatment (24 h at 38 deg rees C) of Euglena gracilis cells - we observed some structural change s at the micro- and submicroscopical level in comparison with control samples. Many giant cells appeared in the culture and some of them cre ated starfish formations. Euglena protein sulfhydryl group content dec reased after HS in all series from 38 to 43 degrees C. The stress temp erature 38 degrees C was optimum for inducing of both cell gigantism a nd the production of Euglena heat shock proteins. We suppose, that the reprogramming of gene expression and the decrease (oxidation) of Eugl ena protein sulfhydryl groups after heat stress has probably a relatio n to structural and ultrastructural changes observed in Euglena gracil is cells in the recovery period. The production of viable giant Euglen a cells may by considered as a return to an ancestral condition, when the growth temperatures were higher than normal.