Biology bulletin of the Academy of Sciences of the USSR最新文献

The influence of antitumor preparations 1,2-bisdiazoacetylethane (diazan) and N-nitroso-N-methylurea (NMU) on the inhibition of colony formation after sublethal irradiation and on migration after nonuniform irradiation of mice was investigated by methods of endogenous cloning of hematopoietic stem cells. It was shown that both preparations in the therapeutic doses used in experimental oncology (diazan 150 mg/kg, NMU 8 mg/kg) have no mitostatic effect on the hematopoietic stem cells, while NMU also does not influence their migration. Diazan somewhat stimulated the migration process.

In experiments on cats which had been narcotized with chloralose and immobilized with myo-relaxants, we have studied cerebral cortical responses to stimulation of the visceral system. A peculiarity of the visceral afferent representation is the fact that the convergence of visceral and dermomuscular impulses is achieved with predominance of somatic signals in the cortical zones of visceral representation, with the exception of the focus of maximal activity (FMA). A second peculiarity is the fact that the visceral afferent systems develop habituation to prolonged stimulation. The principles of this development are similar to the general principles described in the literature for other sensory systems.

The mutagenic actin of cyclophosphane (CP) on the bacterium S. typhimurium TA 1950 in host-mediated assay (mice) was investigated. The mutagenic effect of CP depended on the dose. Administration of carbon tetrachloride (CCl4) to the animals modified the level of the mutagenic effect of CP. The direction of the modification depended on the time elapsed between the introduction of CCl4 and CP. The use of adrenalectomized animals as the mediator led to an increase in the frequency of mutations induced by CP in indicator bacteria.

It was shown in experiments on rats, dogs, and monkeys, irradiated with x rays or the gamma rays of 60 Co, that a decrease in the indices of phagocytosis is observed only 3-4 weeks after irradiation. It is concluded that the absorptive function of mature neutrophils in radioresistant, and the cells whose maturation occurred after the influence of ionizing radiation are inadequate.

The influence of various systems of freezing (-196 degrees C) and thawing on the protein-synthesizing activity of cell-free extracts from Krebs II ascites carcinoma of the rat liver and from wheat germ was studied. It was established that the biosynthesis of proteins, stimulated by exogenous templates, is decreased in the case of slow systems of freezing and warming of cell-free extracts from Krebs II ascites carcinoma. Similar results were obtained in an investigation of the endogenous protein-synthesizing activity of a cell-free extract from the rat liver and Krebs II ascites carcinoma. No significant decrease in the translating activity of the cell-free extract from wheat germ was observed in the investigated systems of freezing and warming. It was shown that the greatest sensitivity to the action of low temperatures is possessed by a cell-free extract from Krebs II ascites carcinoma.

We have studied the influence of selection for behavior in female silver foxes upon their adrenal reactivity to ACTH. It has been found that in the first year of life, in females from a population selected for domesticated behavior (tame), there is no differentiated adrenal response to different doses of ACTH. In wild females during the first year of life, varying strength of adrenal response to large and small doses of ACTH is noted. During the second year of life, the differential adrenal response to different doses of ACTH is improved in females of both behavioral groups; the reactivity of tame second-year females to small doses of corticotrophin surpasses that of wild second-year animals. It is concluded that during ontogeny in domesticated silver fox females there is a retardation in the establishment of an adequate response to ACTH by the adrenals, as compared to nondomesticated females.

The possibility of transport of free and heparin-bound histamine along the concentration gradient through bimolecular lipid membranes (BLM) and the influence of various factors on it was studied. It was shown that histamine is capable of diffusing through BLM in the form of a singly charged cation. In contrast to histamine, neither heparin nor the histamine-heparin complex (HsHC) penetrates through BLM. It was established that the action of histamine-liberating factors -- increasing the ionic strength to 0.15 and the addition of trypsin to the solution -- on HsHC leads to the appearance of transport of histamine through the BLM as a result of an increase in the concentration of free histamine in solution.

In an age of a scientific and technical revolution, when many operators work in structures shielding the geomagnetic field (GMF) by a factor of 100 or more, the urgency of this problem is shown. To study the effect of a hypogeomagnetic environment on warm-blooded organisms, series of experiments were conducted on rabbits that passed through entire embryogenesis and grew to an age of one month in a shielded chamber where the GMF was reduced by a factor of 600. The results obtained confirm that the effect of the GMF is needed for normal development of the organism. Degenerative disturbances in the liver, myocardium, and gastrointestinal tract were noted in animals reared in a reduced GMF. Structural and energy metabolism are disturbed, and the marked inhibition of activity of the investigated enzymatic systems, except the glycolytic, is shown. Changes in the motor activity of the experimental animals and insufficiency of the neuromuscular apparatus were revealed. The mortality rate among the experimental animals was statistically higher than for the controls. The authors raise the question of the need for further comprehensive investigations of the established effects of the hypogeomagnetic environment.

Literature and personal data are presented concerning the genetic effect of 160 pesticides. Methods and test objects used to detect genetically active pesticides are analyzed. A scheme is proposed for screening pesticides with mutagenic effect at all levels of the organization of life. In connection with the pervasive influence of pesticides on the biosphere, the necessity of detailed study of the genetic effects of pesticides on a series of test systems is stressed.

An electron-microscopic study was made of the suprachiasmatic and acurate nuclei of the hypothalamus, the intermediate and anterior lobes of the hypophysis in infertile female rats, sterilized by one injection of testosterone propionate in the critical period of their sexual development. Deformed synapses were detected on the bodies of the neurocytes of the suprachiasmatic nucleus, the accumulation of secretory granules and synaptoid vesicles in the nerve terminals of the intermediate lobe, and an intensive formation of secretion by the prolactin-producing adenocytes of the hypophysis. The mechanism of the masculinizing effect of androgens at the level of the hypothalamus and the possibility of correction of the anovulatory cycle in sterile females are discussed.