Semax and Selank Inhibit the Enkephalin-Degrading Enzymes of Human Serum

Dose-dependent effect of synthetic heptapeptides Semax (Met-Glu-His-Phe-Pro-Gly-Pro) and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) on the enkephalin-degrading enzymes of human serum was demonstrated. The inhibitory effects of Semax (IC₅₀10 M) and Selank (IC₅₀20 M) are more pronounced than that of puromycin (IC₅₀10 mM), bacitracin, and some other inhibitors of peptidases. Beside the heptapeptides, their pentapeptide fragments also possessed an inhibitory effect; tri-, tetra- and hexapeptide fragments did not display such an effect. As the above enzymes take part in degradation of not only enkephalins but also other regulatory peptides, it can be assumed that one of the mechanisms of biological activity of Semax and Selank is related to this inhibitory activity of theirs.     

Characteristics of force-frequency relations in the myocardium of the squirrel Citellus undulatus

The force-frequency relationship (FFR) in papillary muscles of the heart of active ground squirrel in different seasons was studied. For comparison, similar preparations from rat and rabbit were used. It was shown that the FFR of papillary muscles of active ground squirrel undergo significant seasonal changes. In summer and a part of autumn squirrels, a negative staircase (a decrease in the isometric force with increasing stimulation frequency) similar to that in adult rat was revealed. The FFR of the majority of autumn, winter and spring squirrels were polyphasic and contained both positive and negative components. Changes in the force in response to the introduction of pauses at a constant stimulation frequency were recorded. Two types of the post-rest recovery pattern were revealed in the myocardium of ground squirrels. For frequencies range with the negative direction of FFR, a typical pattern of rest-potentiation similar to that in rat papillary muscles was observed. The amplitude of the first post-rest contraction (F1) was usually higher than that of the preceding steady-state contraction. In papillary muscles of autumn animals the F1 value was greater that in summer, which suggests an enhanced release of Ca2+ from the sarcoplasmic reticulum. There was no post-rest potentiation in the range of frequencies with positive direction of FFR, and the post-rest recovery pattern in these cases was principally different from those of rat and rabbit preparations. It was proposed that seasonal differences of the FFR of active ground squirrel heart are associated with changes in the ratio of activities of the calcium-transporting system in the hibernation period.     

Comparative characteristic of serpin--alpha-1 proteinase inhibitor in human and mice serum

Serpin alpha-1-proteinase inhibitor have been studied in human subjects and in mice of different lines as acute phase reactant and during tumor development. In humans, there was no difference of serpin activity between men and women. Increased activity was noted in men with acute trauma (acute phase reaction). Comparatively to male, in female mice of different lines decreased activity of serum alpha-1-proteinase inhibitor, was shown. There was no increase of alpha-1-proteinase inhibitor activity during inflammation induced by zymosan administration in mice. alpha-1-proteinase inhibitor belongs to acute phase reactants in humans but not in mice; for mice alpha-2-macroglobulin is a more typical acute phase reactant as compared to alpha-1-proteinase inhibitor. Murine tumor development (hepatoma HA-1, lymphosarcoma LS, Lewis lung adenocarcinoma) was followed by a decreased activity of serum alpha-1-proteinase inhibitor both in successfully treated and untreated groups. According to data of literature, similar dated were obtained in humans with tumors. It was suggested that changes of expressiln of alpha-1-proteinase inhibitor by tumors and its secretion were involved in decreased activity of alpha-1-proteinase inhibitor.     

Oligonucleotides containing disaccharide nucleosides: synthesis, physicochemical, and substrate properties

The efficient synthesis of oligonucleotides containing 2'-O-beta-D-ribofuranosyl (and beta-D-ribopyranosyl)nucleosides, 2'-O-alpha-D-arabinofuranosyl (and alpha-L-arabinofuranosyl)nucleosides. 2'-O-beta-D-erythrofuranosylnucleosides, and 2'-O-(5'-amino-5-deoxy-beta-D-ribofuranosyl)nucleosides have been developed.     

Effects of plasmid pKM101 on the expression of Escherichia coli and Salmonella typhimurium genes under ultraviolet irradiation

The study focused on plasmid pKM101, which is a necessary component of the short-term test of Eim's system (Salmonella-microsome test), to detect the potential carcinogens through their mutagen activity. We found a previously unknown feature of the plasmid to enhance the expression of certain plasmid and chromosome genes. The purpose of the present study was to examine and specify the role of operon mucAB responsible for the mutation properties of the plasmid in activating the expression of bacterial genes. An ultraviolet-induction examination of bacterial genes, with the mutants of plasmid pKM101 affecting operon mucAB being used, showed that the function of genes mucAB did activate, but, on the contrary, suppressed the induction of genes elt (i.e. of genes controlling the formation of LT-toxin of Escherichia coli) and of sfiA (SOS-regulated gen E. col controlling the cell division.     

The development of A. N. Belozersky's ideas in polyphosphate biochemistry

This review covers some trends and approaches to the study of inorganic polyphosphates that originated from the fruitful ideas and pioneering works of A. N. Belozersky. This is, first of all, the elucidation of a close relationship between these biopolymers and nucleic acids in organisms at different evolutionary stages; second, the study of "fossil" reactions in polyphosphate metabolism that permit an understanding of their role in the evolution of phosphorus turnover and cell bioenergetics; third, the possible use of the conservative enzymes of polyphosphate metabolism, e.g., exopolyphosphatases, as molecular chronometers for obtaining additional data concerning the theory of the endosymbiotic origin of eukaryotic cells from prokaryotes.     

Effect of a short-term moderate whole body hyperthermia of healthy humans on their peripheral lymphocytes

A short (75-110 min) mild (39.5 degrees C) whole body hyperthermia of humans does not alter the absolute amount of peripheral lymphocytes immediately after heating, but significantly reduces their relative amount due to neutrophil increase. Body heating does not induce lymphocyte degeneration: their potential viability does not reduce. The total level of lymphocyte oxidative metabolism remains unaltered, while SDG and LDG activities are seen reduced and increased, respectively. Lymphocytes adapt to body heating by inducing thermotolerant state and activating anaerobic metabolism.     

Soil inorganic carbon storage pattern in China

Soils with pedogenic carbonate cover about 30% (3.44 × 10⁶ km²) of China, mainly across its arid and semiarid regions in the Northwest. Based on the second national soil survey (1979–1992), total soil inorganic carbon (SIC) storage in China was estimated to be 53.3±6.3 PgC (1 Pg=10¹⁵ g) to the depth investigated to 2 m. Soil inorganic carbon storages were 4.6, 10.6, 11.1, and 20.8 Pg for the depth ranges of 0–0.1, 0.1–0.3, 0.3–0.5, and 0.5–1 m, respectively. Stocks for 0.1, 0.3, 0.5, and 1 m of depth accounted for 8.7%, 28.7%, 49.6%, and 88.9% of total SIC, respectively. In contrast with soil organic carbon (SOC) storage, which is highest under 500–800 mm yr⁻¹ of mean precipitation, SIC storage peaks where mean precipitation is <400 mm yr⁻¹. The amount and vertical distribution of SIC was related to climate and land cover type. Content of SIC in each incremental horizon was positively related with mean annual temperature and negatively related with mean annual precipitation, with the magnitude of SIC content across land cover types showing the following order: desert, grassland >shrubland, cropland >marsh, forest, meadow. Densities of SIC increased generally with depth in all ecosystem types with the exception of deserts and marshes where it peaked in intermediate layers (0.1–0.3 m for first and 0.3–0.5 m for latter). Being an abundant component of soil carbon stocks in China, SIC dynamics and the process involved in its accumulation or loss from soils require a better understanding.