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

The composition of the fatty acid profiles of Cl. perfringens type A, grown on media with initial pH values from 5.5 to 9.0, was determined by the method of gas-liquid chromatography. The fatty acid profiles are stabilized in 18- to 24-h cultures. Hydrogen ions stimulate the synthesis of cyclopropane carboxylic fatty acids and "desaturase" activity; hydroxyl ions inhibit these processes. The content of saturated fatty acids in the bacteria is regulated by the initial acid-alkaline conditions of the medium. An increase in biomass accumulation under the influence of hydroxyl ions is coupled with a decrease in the energy supply of the bacteria. Possible mechanisms of the development of resistance to hydrogen and hydroxyl ions during the cultivation of Clostridia on a period growth medium are discussed.

The apocrine glands of the oral angle of the squirrel, and of the hairy skin of the body and the anal sacs of the cat possess cholinergic and adrenergic innervation. Their secretory tubules are enlaced by cholinergic nerves containing chiefly non-specific cholinesterase; the acetylcholinesterase concentration in them is very low in the squirrel and i the glands of the skin of the cat's body, and higher in the glands of the anal sac of the cat. The adrenergic nerve fibers of the apocrine glands possess a very low monoamine oxidase concentration; however, their nonmyelinated terminals, lying on the secretory cells and reaching the lumen of the secretory division, are rich in monoamine oxidase. The innervation of the apocrine and eccrine sweat glands is very similar; in the nerves of the apocrine glands, the acetylcholinesterase and monoamine oxidase concentrations are lower in comparison with the nerves of the eccrine glands; the monoamine oxidase concentration is also lower in cells of the apocrine glands. The question of the essential similarity of the innervation of both types of skin glands - skin and sebaceous - is discussed.

From the total number of pesticides applied in the USSR, 18 are classified as being particularly dangerous compounds. Taking into account the self-purifying ability of the regional soils, arbitrary doses of these pesticides have been calculated for the administrative units of the Ukrainian SSR, the Moldavian SSR, and the water basin territories of the principal rivers in the region. This index is of greatest significance for arable and long-cultivated regions of the Crimea, Odessa, Kiev, Kherson, and Volynskiy, and for the Moldavian water basin territories of the Prut, the Dniester, and the Southern Bug.

The influence of the conditions of polymerization and the structure of the polyacrylamide gel (PAG) on the 3-ketosteroid delta 1-dehydrogenase activity of a culture of M. globiforme 193 was studied. A clear dependence of the enzymatic activity on the temperature regime and the duration of the polymerization process was established. The reason for the fall in activity with a rise in temperature and an increase in the duration of the polymerization process is the diminution of the quantity of viable cells. The death of the cells is caused by the action of the monomers. The maximum 3-ketosteroid delta 1-dehydrogenase activity appears when the immobilized cells are maintained in a viable state, accomplished by adopting a short time of polymerization (1--2 min) at a temperature of 4--12 degrees C. The specific activity of free cells of M. globiforme and cells immobilized under these conditions is 0.15 mumoles/mg cells . min. The reason for the low activity in a 20% gel is apparently the limited rate of diffusion of the substrate into the gel, conditioned by the small dimensions of the pores of the gel. A change in the concentration of N,N'-methylene bisacrylamide (MBA) from 0.25 to 2% in 5 and 10% gels does no affect the rate of delta 1-dehydrogenation of the substrate.

In investigations on 30 volunteers 172 electronystagmograms (ENG) were recorded. The tests showed that cumulative exposure to Coriolis accelerations either activates, inhibits, or causes no significant change in the quantitative parameters of nystagmus. A new objective method of individual assessment of the state of vestibular function for use during vestibulometry in hospital, based on comparative assessment of the direction of changes in magnitude of the nystagmus response after continuous cumulation of Coriolis accelerations is suggested. Subjects in whom the velocity of the slow phase (VSF) of nystagmus after exposure to continuous cumulation of Coriolis acceleration (CCCA) exceeds its usual value before CCCA are considered to have high vestibular resistance; subjects in whom VSF of nystagmus falls significantly (or is unchanged) after CCCA are considered to exhibit vestibular instability.

The effect of the antitumorigenic agent diazane (1,2-bis-diazoacetylethane) in the cells of 30 human tumors cultured in vivo in diffusion chambers, implanted intraperitoneally into mice. Twenty-four hours after the introduction of diazane, a decrease in the proportion of DNA-synthesizing cells and the intensity of DNA synthesis to 30--50% of the control values is observed. By 48 hours, the values of these parameters had returned to the initial level.

The changes observed during flight on the whole corresponded with the preflight prognosis and reflected the phase nature of the processes of adaptation. They were shown by blood redistribution symptoms, fluctuations in the main indices of hemodynamics at rest not going beyond the limits of the physiological norm, an increase in the pulse-filling of the head with blood, and a decrease in that of the shank. The reaction of the blood circulation to a physical load and the application of negative pressure varied, and in a number of investigations during flight it was more pronounced than on Earth. The changes observed after the flight appeared regular for the period of readaptation of the reactions of the organism. These reactions bore a functional nature and qualitatively did not differ from reactions observed after other flights, and after the 140-day flight they were, on the whole, less pronounced than after the 96-day flight. In the postflight period to accelerate the process of adaptation a complex of restorative-healing measures was carried out, including mainly a regulation of motor activity, restorative massage of the muscles, remedial physical culture and aquatic procedures. The flight lasting 140 days revealed no contraindications to a further regular increase in the time of cosmic flights and demonstrates once again the possibility of the planned control of the state of a healthy subject in flight and the readiness of the organism for a return to the terrestrial force of gravity.

The influence of acute experimental emotional stress, induced by electrical stimulation of the hypothalamus and skin in immobilized adult male rabbits of the Chinchilla breed, was determined in complex physiological and cytochemical investigations. Three groups of animals were distinguished according to the nature of the cardiovascular responses: resistance, adaptable, and predisposed to the development of stress. In animals predisposed to the development of emotional stress, different metabolic changes are induced in different extraneural nodes of the autonomic nervous system and sympathetic chain. The most pronounced changes occur in the nodose ganglion of the vagus nerve; in this case changes of a catabolic nature predominate over anabolic changes in it. In the stellate ganglion and nodes of the sympathetic chain there is an intensification of anabolic processes. The upper cervical sympathetic node occupies an intermediate position with respect to the nature of the metabolic changes. The presence of a tendency for an increase in the activity of the "fast" isoenzymes of lactate dehydrogenase was demonstrated in the conducting system of the heart.