[Reversibility of the effect of the change in time of the magnetic field on molluscan neurons]. / Ob obratimosti vliianiia meniaiushchegosia vo vremeni magnitnogo polia na neirony molliuska.

Influence of a single impulse of magnetic field (MF) of trapezoidal shape with 10 Oe amplitude on neuron electrical activity (EA) of Lymnaea stagnalis was studied. It has been found that both leading and trailing edges of MF impulse separately were able to change EA of the cells. Nevertheless the impulses with a short time between the edges were found to be of small efficiency. It was suggested that the influence of the rotation electric field induced by the leading edge of this pulse was abolished by the influence of that induced by the trailing edge. The efficiency of MF impulse influence increased with increasing the interval between their edges and ran to the maximum during 10 s interval.

[Spectrophotometric study of the system DNA-lipid]. / Spektrofotometricheskoe issledovanie sistemy DNK-lipid

The effect of some physical and chemical factors on the system DNA-lipid and its components was studied by spectrophotometry. A change of optical density (D) of watersalt suspensions of lipid total fraction in the range of wavelengths from 200 to 350 nm with the change of ionic strength from 0 to 1 M NaC1 and temperature from 20 to 100 degrees C was investigated. Measurements were carried out under various temperature regemes. In all cases a bell-like irreversible dependence of D on temperature was observed. Its parameters were essentially dependent on the temperature heating of the samples and medium composition. In the presence of DNA the parameters of the curve were changed significantly and depended on the ratio DNA:lipid. An inhibiting effect of DNA on the oxidation of lipids and stabilization of liposomes as well as thermic destruction of DNA stabilized by lipids were observed under certain conditions. The data obtained allowed a conclusion concerning the formation of lipodesoxinucleic complex. It was shown that when a large number of lipid oxidation products was accumulated in the system a chemical modification of DNA with the change of its secondary structure went on.