Zhurnal evoliutsionnoi biokhimii i fiziologii最新文献

Using fishes as an example (32 species, II families) the relationship between taste attractiveness of free amino acids (L-isomers) and their physicochemical and biological properties was analyzed. It is shown that the essential amino acids, which are of the highest nutritional requirement for an organism, have lower taste attractiveness in fishes than nonessential ones. Only in 6 species of 32 investigated ones (sun- bleak Leucaspius delineatus, European minnow Phoxinus phoxinus, dace Leuciscus leuciscus, chub Leu- ciscus cephalus, blue gourami Trichopodus trichopterus, pearl gourami Trichopodus leerii) the relation- ship between taste preference and molecular weight of amino acids was confirmed statistically, in all cases being negative. Only in 2 species a statically significant correlation between taste properties of amino acids and the dissociation constant (K₁) was found (positive in stone loach Barbatula barbatula and negative in lake charr Salvelinus namaycush). A positive correlation between taste preference and the value of isoelectric point (pI) of amino acids was found in one species (roach Rutilus rutilus) and negative correlation - in 2 species (brown trout Salmo trutta, Arctic char Salvelinus alpinus erythrinus). A significant correlation between taste attractiveness and solubility of amino acids in water.was found in 2 species (chum salmon Oncorhynchus keta and navaga Eleginus nawaga), negative in both cases. Acidic and polar uncharged amino acids more often possess flavor that stimulates food consumption than basic and non-polar ones, L-isomers of amino acids than D-isomers, amino acids with an amino group in cc-position than in β-position. Amino acids are more attractive than their salts. Aromatic amino acids possess attrac- tive taste much less than sulfur-containing or acyclic ones. Thus, in the majority of fish species the relationship between taste attractiveness of free amino acids and many of their physical, chemical and biolo- gical properties is absent or low, indicating their indirect nature and difficulty of revealing these relation- ships.

Literature and own data on the central effects of regulatory peptides (115 substances from 32 families) have been analyzed. The peptides produced by peripheral tissues affect the brain through the almost impenetrable for them blood-brain barrier and evoke numerous central effects. The mechanisms of this action are as follows: binding of the peptide with specific receptors on vagal afferents and in the circumventricular organs as well as (to a lower extent) penetration into the brain with the aid of specific transport systems or by the way of simple diffusion. The number of these cross-barrier communications depends on the evolutionary age of the regulated physiological function: the more ancient the function is, the more peripheral peptides affect the mechanisms of its brain regulation.

The composition and content of carotenoids in tissues of Anadara kagoshimensis (Tokunaga, 1906) under conditions of food deprivation were analyzed over the interval of 30 days. By the end of the experiment a slight and uneven decrease of the level of total carotenoid content in tissues of foot, hepatopancreas, gills and in the sum of remaining tissues was observed. Initially β-carotene, pectenolon, zeaxanthin, diatoxanthin, alloxanthin and esters of the latter four carotenoids were found in tissues extracts. The qualitative composition of carotenoids in the examined tissues was similar. In the course of the experiment changes were noted in both the composition of carotenoids and their content. Changes common for all tissues were shown: β-carotene disappeared on days 3-4, over the interval of 30 days a decrease in the content of the esters of pectenolon, alloxanthin, zeaxanthin and diatoxanthin and an increase in the level of pectenolon and alloxanthin were observed. Tissue specificity was revealed: in foot and hepatopancreas tissues, at the background of decrease of the total content of esters of carotenoids, a considerable increase of pectenolon and alloxanthin concentration accompanied by an increase of diatoxanthin and zeaxanthin was observed; in gills and the sum of the remaining tissues, under similar increase in pectenolon and alloxanthin concentration, the level of diatoxanthin and zeaxanthin remained at the initial level or was even somewhat lower. The diagram of carotenod transformation is supplemented for Anadara kagoshimensis.

Ecdysteroids are multifunctional hormones regulating virtually all morphogenetic processes in insects. Their role in stress and immune response regulation is less known. Here we studied 20-hydroxyecdysone effect on synthesis of the antimicrobial peptides in larvae of Calliphora vicina. An inverse correlation was found between 20-hydroxyecdysone titer and the concentration of antimicrobial peptides in the hemolymph of unaffected and bacteria-immunized insects. High and low doses of 20-hydroxyecdysone, injected simultaneously with bacterial cells, had an opposite effect on antimicrobial peptide synthesis in the diapausing larvae. Morphogenetically effective doses of 20-hydroxyecdysone demonstrated immuno-suppressive activity. Low doses of 20-hydroxyecdysone, on the contrary, moderately stimulated synthesis of the antimicrobial peptides. These data suggest that ecdysteroids are directly involved in regulation of the immune system activity and the final effect is dose-dependent.

Sleep is characterized by cycling and consecutive alternation of different phases and stages, each of them featuring intrinsic changes of vegetative regulation with oscillations of heartbeat rate that may cause development of cardiac rhythm disorders especially under presence of concomitant somatic diseases. This paper deals with the problems of interrelationships between disturbances of heart conduction and obstruc- tive sleep apnea. It is shown that some mechanisms of the occurrence of brady-arrhythmias (first of all, features of vegetative regulation with increasing parasympathetic tone) under sleep arrests are inherent to human divers as well as to mammals conducting water or near-water way of living associated with forced breathing delays at diving and prolonged staying under water. These mechanisms may carry out defense function.

Characteristic features of indicators of the thyroid status and lipoprotein content were found in blood serum of girls and women representing Buryat ethnos and europeoids. In representatives of Buryat ethnos, as compared to europeoids, a development of adaptive reactions from the side of pituitary-thyroid part of the neuroendocrine regulation system was noted (increased concentrations of free T3 fraction in girls and decreased TTH levels in women). Changes in lipid metabolism parameters lie in lower concen- trations of atherogenic fractions of cholesterol in Buryat girls and increased level of cholesterol-contai- ning blood components in adolescent europeods. At older age period a reverse tendency is observed, cha- racterized by an increased activity of lipid metabolism in representatives of the indigenous nationality.

In the last years intranasally administered insulin (II) is widely used to treat Alzheimer's disease and other cognitive disorders. Meanwhile, it is little used to treat the type 2 diabetes mellitus (DM2); which is due to insufficient knowledge of molecular mechanisms of its action on hormonal and metabolic status of an organism. The effect of II on the activity of hypothalamic signaling systems, which plays a key role in the central regulation of energy metabolism, is still poorly understood. The aim of the present work was to study the effect of five-week treatment of male rats with neonatal model of DM2 using 11 (0.48 IU/rat) on metabolic parameters and on functional activity of the hypothalamic signaling systems. It was shown that treatment of diabetic rats with II'(Group DI) normalized plasma glucose level, restored glucose tolerance and its utilization. In the hypothalamus of rats of the Group DI the-regulatory effects of agonists of type 4 melanocortin receptors (MC4R), type 2 dopamine receptor (D2-DAR) and subtype 1B serotonin receptor (5-HTIBR) on adenylyl cyclase (AC) activity, which were reduced in DM2, restored. Moreover, the inhibitory effect of 5-HTIR agonists even was increased as compared to control. In the Group DI, the res- toration of AC regulation by hormones was accompanied by a significant increase in the expression of genes encoding 5-HTIBR and MC4R. Along with this, the attenuation of the AC stimulating effect of D1-DAR agonists and the decreased expression of Drdl gene were found, promoting the enhancement of the negative dopamine effect on AC activity. The II treatment did not significantly affect the expression of genes encoding insulin receptor and insulin receptor substrate 2, which was reduced, though to a small extent, in the hypothalamus of diabetic rats. Thus, the II treatment of rats with the neonatal model of DM2 partially restores the hypothalamic AC signaling pathways regulated by melanocortins, serotonin and do- pamine, which is one of the mechanisms of positive influence of II on energy metabolism and insulin sensitivity in the peripheral tissues.

The role of orexin in the organization of sleep-wakefulness cycle (SWC) is well known. The aim of this study was to examine the terms of formation of the orexinergic system in the rat postnatal ontogenesis and to assess the role of orexin A in SWC organization under normal conditions and after prenatal hypoxia realized on days 14 and 19 of the embryogenesis. SWC was investigated in 30-day-old rats with elect- rodes implanted into the somatosensory and occipital cortex. Immunoreactivity in the orexinergic structures of the lateral hypothalamus was also studied. It was shown that in the control 14-day-old animals the orexinergic structures were at the formation stage whereas in the 30-day-old ones they were already formed as in adults. In the 14-day-old rats prenatal hypoxia evoked retardation of the orexinergic system for- mation terms. In the 30-day-old rats the orexinergic system activity after hypoxia was increased, with hypoxia on day 19 activating this system stronger than hypoxia on day 14 of gestation. These changes were reflected in the SWC formation in the 30-day-old rats as shortening of the slow-wave phase of sleep, increase in the fitful sleep and in the number of transitions from the slow-wave to the fast-wave phase of sleep. The results obtained are discussed in the light of the adaptation-compensatory role of the orexinergic system in the postnatal ontogenesis after prenatal damage affecting the central neural system.

Inotropic effects of yttrium acetate (Y³⁺) on contractions of myocardium preparations of the frog Ra- na ridibunda as well as on respiration and the inner membrane potential (Δψmito) of isolated rat heart mi- tochondria were studied. It was found that 2 mM yttrium in Ringer solution significantly reduced the am- plitude of myocardium contractions evoked by electric stimulation and increased the half-relaxation time (n = 5). In experiments with Ca²⁺, Y³⁺ decreased Ca²⁺-dependent oxygen consumption rate of rat heart mitochondria, energized by glutamate and malate, impeded the reduction in respiration of these mito- chondria in state 3 or uncoupled by 2,4-dinitrophenol, and inhibited Ca²⁺-induced decrease in their inner membrane potential. These data are important to better understand the mechanisms of Y³⁺ effects on myocardial calcium-dependent processes. Possible mechanisms of negative inotropic effect of Y³⁺ on the myocardium and its influence on the Ca²⁺-dependent processes in rat mitochondria are discussed.

Protein reabsorption in the proximal tubules (PT) of the frog kidney was studied by the methods of immunohistochemistry, fluorescent and confocal microscopy. Yellow fluorescent protein (YFP) was introduced in combination with other proteins. Reabsorption of YFP introduced simultaneously with ly- sozyme or green fluorescent protein (GFP) did not differ from the result of YFP injection only. Previous lysozyme injection did not change YFP absorption in contrast to YFP uptake reduced after GFP pretreat- ment. Lysozyme loading for 4 days resulted in a significant reduction in YFP absorption. The results show that receptor-mediated endocytosis in the frog kidney depends on the molecular nature of absorbable ligands, conditions of their competitive absorption and lysosomal accumulation in epithelial PT cells.