Model of radiation-accelerated aging and its specific features

We conducted a lifetime study of the content of oxidized and methylated guanine in the urine of intact and irradiated mice. For statistical processing of the results, we used the trial period method created by A.A. Konradov, which was unpublished during the author’s lifetime. We prove that there are oscillating components in the age dependence of the concentration of oxidized and methylated guanine in mice urine. For intact animals, a 7-month oscillation period is the most probable (p = 0.001). For irradiated mice, a disruption in the seasonal oscillation rhythm in the concentration of oxidized and methylated guanine in urine was noted, which is peculiar to radiation-accelerated aging.     

Determination of binding constants of lipopolysaccharides of different structure with chitosan

The interaction of endotoxins--lipopolysaccharides (LPS) different in degree of the O-specific chain polymerization--with 20- and 130-kD chitosan was studied using the competitive binding of LPS with the complex of chitosan-anionic dye (tropaeolin 000-2) and the direct binding of (125)I-labeled LPS with chitosan immobilized on Sepharose 4B. The interaction of 20-kD chitosan with LPS was non-cooperative, and immobilization of the polycation on Sepharose resulted in its binding to (125)I-labeled LPS with a positive cooperativity. The interaction of LPS possessing a long O-specific chain with 130-kD chitosan was characterized by negative cooperativity. Binding constants of LPS with the polycation and the number of binding sites per amino group of chitosan were determined. The interaction affinity and stoichiometry of the LPS-chitosan complexes significantly depend on the LPS structure and concentration in the reaction mixture. The increase in the length of carbohydrate chains of LPS results in increase in the binding constants and decrease in the bound endotoxin amount.     

Multimodal sensory organs in larvae of some insect species

The morphological diversity of antennal sensory organs in larvae of Galeruca sp. (Coleoptera, Chrysomelidae), Limnephilus centralis (Trichoptera, Limnephilidae), and Eristalis tenax (Diptera, Syrphidae) was studied. A sensory cone on the antenna was found in all the species studied. The cuticular part of the antennal cone is pierced with pores. No significant differences in the shape of the antennal cone were revealed. The innervation patterns of the antennal cone varied from single cells in the leaf beetle larvae to groups of cells with a common scolopoid sheath in the fly larvae. The cone combines several types of sensilla that perform mechanoreceptor, olfactory, and gustatory functions. The morphology and ultrastructural organization of the antennal cone in relation to the heterogeneity of the larval habitats are described.     

New data on birds and mammals population of the Sette-Daban Mountain Ridge

Original materials on the fauna of the northern macroslope of the Sette-Daban Mountain Ridge are presented. Birds and mammals population in different habitats in the basin of the Allakh-Yun River are characterized.     

Magnesium homeostasis: Mechanisms and inherited disorders

Mechanisms of magnesium homeostasis intensively studied over the last 10–15 years by means of pathophysiological and molecular genetic approaches have been considered. Impairments of magnesium homeostasis causes the development of magnesium-deficient states, which have been found in many common diseases (diabetes mellitus, cardiovascular diseases, chronic fatigue syndrome, alcoholism, psychiatric and neurologic diseases, etc.), stress condition, effects of some environmental factors as well as therapy with some drugs. Special attention is paid to familial hypomagnesemias caused by genetic defects of magnesium transport systems. The review considers clinical and biochemical characteristics of twelve familial disorders including mechanisms of their development. Deeper understanding of mechanisms of regulation of magnesium homeostasis will results in the development of new approaches in diagnostics, prophylaxis and treatment of magnesium-deficient conditions.     

Entrapment of herbal extracts into biodegradable microcapsules

The microcapsules with entrapped herbal water-soluble extracts of plantain Plantago major and calendula Calendula officinalis L. (PCE) were prepared by layer-by-layer (LbL)-adsorption of carrageenan and oligochitosan onto CaCO₃ microparticles with their subsequent dissolving after the treatment of EDTA. Entrapment of PCE was performed by using adsorption and co-precipitation techniques. The co-precipitation provided better entrapment of PCE into the carbonate matrix compared to adsorption. In vitro release kinetics (AGJ) was studied using artificial gastric juice. Using the model of acetate ulcer in rats it has been demonstrated that PCE released from the microcapsules accelerates gastric tissue repair.     

Gibberellin A<Subscript>3</Subscript> detection in plants with high-performance liquid chromatography

A new method of gibberellin A₃ detection based on high-performance liquid chromatography has been elaborated. It combines high accuracy and low cost, and includes the following stages: fixation with liquid nitrogen; extraction of alcohol-soluble substances; purification with freezing, reextraction in ethyl acetate, and thin-layer chromatography; and detection with HPLC. Chromatographic conditions and methods of substance identification have been determined. The method allows the use of modest amounts of plant material (5–20 g), at which variability does not exceed 7%, and the total loss of substance is approximately 3%. The results of gibberellin A₃ detection in buckwheat are presented.     

Influence of neuroendocrine shifts in the pubertal period on the working memory operation in adolescents

It was found that the volume of working memory in adolescents at the initial pubertal stages (II–III) was lower than in adults. Analysis of the event-related potentials (ERPs) in various cortical areas in adolescents when they compared two successive pictures revealed specific features of neurophysiological mechanisms of visual working memory at the early pubertal stages. As compared to adult subjects, the adolescents were characterized by longer latencies and higher amplitudes of the early components of the ERPs. Certain differences were revealed in the functional organization of working memory both at the stages of stimulus fixation and in its comparison with the current information.