Dynamics of Thyroid Hormones at Early Stages of Development of the Sturgeon Acipenser güldenstadti

Using radioimmunological method, the level and dynamics of thyroid hormones, thyroxine (T₄) and triiodothyronine (T₃) were studied in eggs, embryos, and pre-larvae of the Russian sturgeon Acipenser güldenstadti L. The level of hormones in eggs was higher than in the individuals at the stage of hatching. In embryogenesis the content of T₄ and T₃ hormones changed simultaneously, while in pre-larvae, synchronization was absent. The maximal T₄ values in sturgeon pre-larvae were recorded not long before transition to active nutrition. The T₄ level was statistically significantly higher in eggs and larvae developed from the eggs with a high degree of fertility. The problem of participation of thyroid hormones in processes of development and formation of adaptive mechanisms in early ontogenesis of sturgeons is discussed.     

Forecast of the Health Status, Working Capacity, and Professional Successes under Arid Zone Conditions

Forecasting data on the human heat resistance, professional successes, and health level under hot arid conditions of Turkmenistan are described. A relationship has been established between the characteristics of the thermoregulation system performance under thermoneutral environments, which is shown by the skin surface temperature, and the organism's capacity to maintain a high level of working capacity on heat exposure. The skin temperature patterns are shown to be informative when analyzing the organism's heat state and forecasting the extent to which the total working capacity decreases in response to the intensive heat effect. On the basis of the findings, we developed the criteria for psychophysiological professional selection of linemen for the work under hot arid zone conditions of Turkmenistan. A comparative analysis of the health status of women employed in industry and of housewives living in the arid zone has been carried out using the automated system for the quantitative estimation of risk of the major pathological syndromes (ASQEPS). Groups with tense adaptation have been detected. Analysis and comparison of the syndrome rating in the test groups make it possible to estimate the effect of natural climatic and industrial conditions on the risk of development of major noninfectious diseases and to formulate recommendations for health maintenance.     

Phylogenetic Diversity of Aerobic Saprotrophic Bacteria Isolated from the Daqing Oil Field

A diverse and active microbial community in the stratal waters of the Daqing oil field (China), which is exploited with the use of water-flooding, was found to contain aerobic chemoheterotrophic bacteria (including hydrocarbon-oxidizing ones) and anaerobic fermentative, sulfate-reducing, and methanogenic bacteria. The aerobic bacteria were most abundant in the near-bottom zones of injection wells. Twenty pure cultures of aerobic saprotrophic bacteria were isolated from the stratal waters. Under laboratory conditions, they grew at temperatures, pH, and salinity values typical of the stratal water from which they were isolated. These isolates were found to be able to utilize crude oil and a wide range of hydrocarbons, fatty acids, and alcohols. Phylogenetic analysis carried out with the use of complete 16S rRNA sequences showed that the isolates could be divided into three major groups: gram-positive bacteria with a high and a low G+C content of DNA and gram-negative bacteria of the -subclass of the Proteobacteria. Gram-positive isolates belonged to the genera Bacillus, Brevibacillus, Rhodococcus, Dietzia, Kocuria, Gordonia, Cellulomonas, and Clavibacter. Gram-negative isolates belonged to the genera Pseudomonas and Acinetobacter. In their 16S rRNA sequences, many isolates were similar to the known microbial species and some probably represented new species.     

Unit responses of the cerebellar cortex to stimulation of the vagus nerve and nerves of the limbs

Responses of 74 cerebellar cortical neurons to electrical stimulation of the vagus nerve and its gastric branches and also of the limb nerves were recorded extracellularly in experiments on rats anesthetized with chloralose and pentobarbital. Phasic and tonic unit responses were similar to all types of stimulation, but fewer neurons responded to stimulation of the vagus nerve than to stimulation of the limb nerves. Monosensory neurons responding only to visceral stimulation, were not found. Among cells giving a phasic response, some had a short and others a long latent period. The latent period of responses of all types was longer to vagal stimulation than to stimulation of the limb nerves. The maximal frequency of rhythmic responses to vagal stimulation was 8/sec, compared with 16/sec for stimulation of the limb nerves. Tonic responses of the neurons were excitatory, inhibitory, and mixed. The type of unit response could vary depending on the frequency and repetitiveness of the stimuli but was otherwise independent of the type of stimulation.N. I. Pirogov Vinnitsa Medical Institute. I. M. Sechenov Institute of Evolutionary Biochemistry and Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 4, No. 5, pp. 471–479, September–October, 1972.     

Responses of cerebellar Purkinje cells to mechanical stimulation of the Achilles' tendon

Responses of cerebellar Purkinje cells to mechanical stimulation of the Achilles' tendon were studied in unanesthetized decerebrate cats. Approximately two-thirds of the Purkinje cells tested were activated in response to stimulation through climbing fibers, i.e., they generated a complex spike. In half of these cells (group A) the probability of appearance of a complex spike to a blow on the tendon was from 0.5 to 0.9 and the latent period of response from 20 to 25 msec. Purkinje cells with a latent period of response of over 35 msec were characterized by low probability of response (under 0.5) to a tap (group B). Responses of Purkinje cells to excitation of mossy fibers were weaker and more varied.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 13, No. 2, pp. 159–167, March–April, 1981.     

Production of Oil-Releasing Compounds by Microorganisms from the Daqing Oil Field,China

Twenty pure cultures isolated from formation waters of the Daqing oil field were studied with respect to their capacity to produce surface-active compounds in media with individual hydrocarbons, lower alcohols, and fatty acids. Aerobic saprotrophic bacteria belonging to the genera Bacillus, Brevibacillus, Rhodococcus, Dietzia, Kocuria, Gordonia, Cellulomonas, Clavibacter, Pseudomonas, and Acinetobacter decreased the surface tension of cultivation media from 55–63 to 28–44 mN/m. Strains of Bacillus cereus, Rhodococcus ruber, andBacillus licheniformis produced biosurfactants most actively. Bacteria of the genera Rhodococcus, Dietzia, Kocuria, and Gordonia produced exopolysaccharides in media with hydrocarbons. Culture liquids of the strains of R. ruberand B. licheniformis exhibited an oil-releasing effect. Thus, the Daqing oil field is inhabited by aerobic bacteria capable of producing effective oil-releasing agents.     

Cumulative effects of alcohol (ethanol) on the activity of Purkinje cells in the cat cerebellum

The effects of three consecutive injections of 2 ml/kg 30% alcohol (ethanol, i.v.) on the activity of identified cerebellar Purkinje cells were investigated during experiments on adult cats anesthetized by a Nembutal-chloralose mixture. It was found that repeated alcohol injections exert a cumulative effect on the firing rate of these cells. The alcohol-induced rise in Purkinje cell firing rate, produced by excitation of the mossy fibers, was generally accompanied by a reduction in that of cells responding to excitation of climbing fibers. The inhibitory pause occurring after complex discharges in cerebellar Purkinje cells grew shorter with successive alcohol injections.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 19, No. 1, pp. 74–80, January–February, 1987.     

Effect of Thyroid Hormones on Imprinting of Chemical Signals at Early Ontogenesis of the Sturgeon Acipenser gueldenstaedti

Under laboratory experiments on the fry of the Russian sturgeon Acipenser gueldenstaedti Br. the reaction of attraction to the model chemical stimulus morpholine imprinted at the larval age was recorded. It has been established that both intensity of the reaction of attraction and duration of the sensory period of imprinting are affected by factors changing the level of thyroid hormones, thiourea (TU) and triiodothyronine (T₃), in the larva organism. The conclusion has been made that the thyroid hormones participate in processes of imprinting of chemical signals in sturgeon.