Hyperthermia and other factors increasing sensitivity of Euglena to mutagens and carcinogens

Abstract

The effects of different factors (temperature, light, enzymic activation) on the ability of selected mutagens and carcinogens to induce hereditary bleaching of Euglena gracilis were investigated. In the resting medium, the elevation of incubation temperature from 25 degrees C to 37 degrees C increased significantly the effect of all compounds tested on the frequency of bleached mutants of E. gracilis. The effect of light is not so unambiguous. While nitrosoguanidine (NG) exhibited practically the same bleaching activity both in the light and dark, the mutagenic effect of sodium azide (SA), nitrovin (NV), nitrosoethylurea (NEU), and benzo(a)pyrene (BP) was decreased in light. On the other hand, the light increased the bleaching activity of 5-nitro-2-furylacrylic acid (NFAA) significantly. The activation mixture S9 increased bleaching effect of NFAA and BP, whereas other mutagens were partially (NG and SA) or completely (NV and NEU) inactivated.

Effect of heat shock on the mutagenicity of mutagens and carcinogens in Euglena gracilis

“…Results concerning the effect of elevated temperature (37°C) on the mutagenicity of some chemical agents under different conditions have been discussed in previous papers [6,7]. In this paper we demonstrate that heat shock treatment (42°C for 15 min) applied to Euglena cultures significantly increases the frequency of hereditary loss of plastids of cells treated with mutagens.…”

“…A temperature of 37°C for 15 min does not increase the bleaching effect as compared with that observed after 27°C. This temperature (37°C) was used for 1 3 24 1 3 24 1 3 24 1 3 24 1 3 24 1 3 24 1 3 24 1 3 24 1 3 350 350 390 340 350 390 360 360 72 340 360 400 340 350 39 1 340 340 88 340 350 360 323 340 3 comparison of results reported in previous papers [6,7] in which the synergistic effect of elevated temperature (37°C for 24 h) and mutagens on Euglena gracilis was observed.…”