[Effect of antioxidant-ambiol on the radiation adaptive response].

For studying of the mechanism of adaptive response of plants the seeds of soft wheat Triticum aestivum cultivar Moscovskaya 39 were irradiated in doses 0.25, 50 and 0.25 + 50 Gy and the frequency of cells with aberrations and the mitotic activity in the meristem of seedlings were scored. The pre- and post-treatments of seeds with antioxidant--ambiol were also used. It was found that the exposure of seeds to 0.25 Gy reduce the effects of challenge dose of 50 Gy: the mitotic index increases and the frequency of cells with aberrations decreases--the adaptive response appear. It was also found that the pretreatment with ambiol reduce the effects of the irradiation in the dose of 50 Gy. Post-treatment was less efficiently. Both treatments raise the adaptive response. The correlation between the frequency of aberrant cells and the mitotic index was found and, regardless of the type of treatment all points of experiment fall on the common regression line with the regression coefficient -0.85 (p < 0.01). These facts serve as evidence (1) that the radioprotective effect by the pre- and post-treatment occurs by a common mechanism and (2) that the in the exhausted concentration antioxidant does not change the extent of genome damage inflicted by irradiation. The evidence is consistent with the hypothesis that a nonspecific inducible process of stimulated repopulation was a mechanism of adaptive response of plants.

[On antimutagenesis mechanism in plants].

The effect of nitrosylmethylurea (NMU) on the mitotic index and the frequency of cells with aberrations, as well as the effects of pre- and posttreatment with antioxidant ambiol on the NMU effects were studied on seedlings of common winter wheat Triticum aestivum, cultivar Moskovskaya 39. Both pre- and posttreatment with ambiol resulted in antimutagenic effect but after posttreatment, the effect was lower. Irrespective of type of seedling treatment with ambiol and the time of their fixation (45, 48, and 51 h), when mitotic index is plotted versus frequency of cells with aberrations, all experimental points fall on the same regression line with coefficient of correlation of -0.82 (P < 0.001). This implies that the same mechanism underlies antimutagenic effect irrespective of when the antimutagen was applied, before or after the knockout mutagen dose. This also suggests that the antimutagenic effect is independent of the degree of the mutagen-induced damage, because by the time of posttreatment, the volume of genome damage is already determined and the antimutagen fails to change it. Finally, this suggests that irrespective of time of antimutagen treatment, the mutation frequency is reduced by the mechanism of stimulated repopulation.

[Effect of Agrobacterium tumefaciens (Smith and Town). Conn. on the functional properties of human blood lymphocytes]. / Vliianie Agrobacterium tumefaciens (Smith and Town). Comm. na funktsional'nye svoistva limfotsitov krovi cheloveka.

Agrobacterium tumefaciens has been shown to affect the proliferation of intact lymphocytes as well as lymphocytes stimulated by PHA action. Inoculation of bacteria into the cultures of intact lymphocytes and incubation during 72 h resulted in increased incorporation of [3H]-thymidine into the DNA of cultivated cells. The bacteria are capable of inhibition of lymphocytes proliferation stimulated by PHA.