Polymyxin B and Related Cyclic Peptides Facilitate Leanness and Reduce Fat Mass and Triglyceride Content in Ageing Rats: Potential Prototype Drugs Against Obesity

Polymyxin B (PMXB) blocks the action of insulin on glucose uptake in vitro. In vivo, it reverses hypoglycemia induced by exogenous insulin. Here we have treated mature male rats daily with PMXB over a period of two weeks. This therapy has decreased body weight by 11%, adipose fat mass by 46% and triglyceride levels by 39%, with no indication of liver or kidney toxicity. Two suboptimal parameters, however, were a decrease in food intake in the first week of treatment and some increase in fasting glucose levels. We have screened for PMXB-analogs having less associating affinity with rat-muscle phospholipids, and revealed that the same therapy using PMXB-derived peptide (nona-PMXB) is most optimal. This PMXB-analog is devoid of antibacterial activity and is four times less toxic than PMXB. Nona-PMXB therapy lower by 10, 32, 35 and 6% body weight gain, fat mass, circulating triglycerides and fasting glucose levels, respectively, in spite of normal or even elevated food intake in nona-PMXB treated rats. In summary, we found that nona-PMXB therapy is capable if inducing leanness in mature rats, particularly at the expense of decreasing fat-mass in adipose tissue. By and large, we suggest that lowering the action of insulin, on fat build-up solely, may be a therapeutically feasible task to fight with human adiposity in the future.     

Modern biotechnologies in estimation of genetic diversity of Ukrainian varieties of hop (Humulus lupulus L.)

Genetic variety estimation of hop gene pool using DNA-typing of highly polymorphic microsatellite loci and optimization of introduction to the culture of in vitro conditions is the important stage of national varieties resources forming, basis of modern nursery and protect mean of varieties property, and also it is necessary for development of molecular methods of selection of planting-stocks free from pathogens.     

Ontogenesis of rat immune system: Proteasome expression in different cell populations of the developing thymus

Immune proteasomes in thymus are involved in processing of self-antigens, which are presented by MHC class I molecules for rejection of autoreactive thymocytes in adults and probably in perinatal rats. The distribution of immune proteasome subunits LMP7 and LMP2 in thymic cells have been investigated during rat perinatal ontogenesis. Double immunofluorescent labeling revealed LMP7 and LMP2 in thymic epithelial and dendritic cells, as well as in CD68 positive cells - macrophages, monocytes - at all developmental stages. LMP2 and LMP7 were also detected by flow cytometry in almost all thymic CD90 lymphocytes through pre- and postnatal ontogenesis. Our results demonstrate that the immune proteasomes are expressed in all types of thymic antigen presenting cells during perinatal ontogenesis, suggesting the establishment of the negative selection in the thymus at the end of fetal life. The observation of the immune proteasome expression in T lymphocytes suggests their role in thymocyte differentiation besides antigen processing in thymus.     

Kinesin-dependent transport results in polarized migration of the nucleus in oocytes and inward movement of yolk granules in meiotic embryos

During female meiosis, meiotic spindles are positioned at the oocyte cortex to allow expulsion of chromosomes into polar bodies. In C. elegans, kinesin-dependent translocation of the entire spindle to the cortex precedes dynein-dependent rotation of one spindle pole toward the cortex. To elucidate the role of kinesin-1 in spindle translocation, we examined the localization of kinesin subunits in meiotic embryos. Surprisingly, kinesin-1 was not associated with the spindle and instead was restricted to the cytoplasm in the middle of the embryo. Yolk granules moved on linear tracks, in a kinesin-dependent manner, away from the cortex, resulting in their concentration in the middle of the embryo where the kinesin was concentrated. These results suggest that cytoplasmic microtubules might be arranged with plus ends extending inward, away from the cortex. This microtubule arrangement would not be consistent with direct transport of the meiotic spindle toward the cortex by kinesin-1. In maturing oocytes, the nucleus underwent kinesin-dependent migration to the future site of spindle attachment at the anterior cortex. Thus the spindle translocation defect observed in kinesin-1 mutants may be a result of failed nuclear migration, which places the spindle too far from the cortex for the spindle translocation mechanism to function.     

Seasonal variability of wing length and eyespots in populations of <Emphasis Type="Italic">Erebia ligea</Emphasis> (L.) (Lepidoptera,Satyridae) in the Middle Urals

The flight period of Erebia ligea (Linnaeus, 1758) in the Sysert District of Sverdlovsk Province lasts from early July until early August only in the odd-numbered years. The species is characterized by protandry, its males emerging 5–7 days before females. Erebia ligea manifests sexual and seasonal variation of the wing length and diameter of the eyespots in the Middle Urals. According to the literature and newly obtained data, the relative male/female wing length varies within the species range. The vectors of the seasonal variation of the body size are opposite in the males and females: in early summer the largest males and the smallest females occur, then mediumsized individuals appear, while the smallest males and the largest females fly at the end of the warm period. Although the males of Erebia ligea are larger than females, the latter have larger eyespots on the wings. Seasonal variation of the diameters of the forewing eyespots is largely similar in the two sexes: individuals with larger spots appear earlier in the season than those with small spots. The eyespots treated as phenes in this study develop on the wings only if the remaining spots of the wing pattern attain a threshold size. A threshold nature was shown for P4 spot in M ₃-Cu ₁ cell of the fore wing and G2 spot in cell M ₁–M ₂ of the hind wing. Individuals with and without phene G2 have opposite vectors of seasonal variation of the sizes of the rest spots of the hind wing pattern. It is apparently the threshold character of variation of these elements of the wing pattern that defines the variation of the proportion of phenetic combinations of the eyespots in the individuals emerging in different periods of the season. Describing phenetic variation at the population level, one should remember that the percentage of the “morphs” or phenetic combinations may vary during a season, especially in the protandric species.