Plasma beta-endorphin and stress hormones in stress and adaptation

The experiments on white rats have shown that the induction of 4 hour stress produces an acute increase in beta-endorphin level, as well as characteristic changes in ACTH, cortisol, insulin, thyroxin and triiodothyronine concentrations. Different types of adaptation (training with short stress periods or injection of rhodiola rosea extract) promote a moderate increase in the amount of serum immunoreactive beta-endorphin, preventing its subsequent stress-induced elevation. Adaptation is characterized by a decrease or total prevention of hormonal changes peculiar to stress. The role of opioid neuropeptides in enhancing stress tolerance and the effect of adaptation factors are discussed.     

Dehydroepiandrosterone sulfate effect at aldosterone level under cold exposure

It had been shown that the blockade with dehydroepiandrosterone sulfate (DHEAS) affects enhanced aldosterone level in doses 1, 5 and 30 mg/kg without the dose dependence under multi-repeated cold exposure. These DHEAS effects are realized through micro-opioid receptors. The DHEAS (30 mg/kg) blocking effect was manifested too, but not through micro-opioid receptors under acute cold exposure.     

Method for automated extraction and purification of nucleic acids and its implementation in microfluidic system

A method and a microfluidic device for automated extraction and purification of nucleic acids from biological samples have been developed. The method involves disruption of bacterial cells and/or viral particles by combining enzymatic and chemical lysis procedures followed by solid-phase sorbent extraction and purification of nucleic acids. The procedure is carried out in an automated mode in a microfluidic module isolated from the outside environment, which minimizes contact of the researcher with potentially infectious samples and, consequently, decreases the risk of laboratory-acquired infections. The module includes reservoirs with lyophilized components for lysis and washing buffers; a microcolumn with a solid-phase sorbent; reservoirs containing water, ethanol, and water-ethanol buffer solutions for dissolving freeze-dried buffer components, rinsing the microcolumn, and eluting of nucleic acids; and microchannels and valves needed for directing fluids inside the module. The microfluidic module is placed into the control unit that delivers pressure, heats, mixes reagents, and flows solutions within the microfluidic module. The microfluidic system performs extraction and purification of nucleic acids with high efficiency in 40 min, and nucleic acids extracted can be directly used in PCR reaction and microarray assays.     

Development of a biochip for quantitative determination of two forms of prostate specific antigen using internal calibration curve

Three-dimensional gel-based microchip allowing simultaneous quantitative detection of total (PSAtot) and free (PSAfree) forms of prostate specific antigen in human serum (in a format "one patient-one biochip") was developed. A method, which doesn't require preliminary construction of calibration curves when performing an assay, was applied for quantitative determination of PSAtot and PSAfree. Gel elements with immobilized antigen (PSA) in different concentration, forming an internal calibration curve, were included in a structure of the microchip, in addition to the elements with immobilized antibodies specific against PSAtot and PSAfree. The specialized software "ImaGelAssay" was used for data processing and interpretation. The sensitivity of the assay performed on biochips was 0.3 ng/ml for PSAtot and 0.2 ng/ml for PSAfree. Variation coefficient for the measurements inside one series of microchips didn't exceed 10%. Correlation coefficient between the results of measurements in human sera obtained on biochips and by the standard ELISA method was 0.988 for PSAtot and 0.987 for PSAfree.     

A medico-genetic study of the population of Western Pamir. VI. Local genetic differentiation in the populations of Western Pamir]

The article comprises the results on the analysis of the structure of the great Pamirs' population (of a higher rank) and of one of its parts, the subpopulation of the valley of the river Bartang. Wright's F coefficient was used for the statistical treatment of the data obtained in the course of the analysis. The FST estimates were obtained from the variances of the frequencies of the genes located in 5 loci (ABO, MN, P, Rh and P.T.C.) culculated for 23 samples of the great populations of the Pamirs and for 9 samples of the population of the Bartang river valley. The general inbreeding coefficient for the Pamirs FIT=0,0323, its random component FST=0,0017 and the non-random component FIS=0.0306.     

Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name ‘soldier flies’, occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 °C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.