Hormonal adaptation determines the increase in muscle mass and strength during low-intensity strength training without relaxation

The study was designed to test the hypothesis that, during strength training, a restricted blood supply to the working muscles stimulates the secretion of anabolic hormones and an increase in the muscle mass and strength can be achieved with significantly lower training loads. During eight weeks, three times a week, 18 young, physically active males trained their leg extensor muscles. Nine subjects (group I) worked at 80% of the maximal voluntary contraction (MVC), whereas the rest (group II) performed their exercise without relaxation and at a lower load (50% MVC). The total training load in group II was significantly lower than in group I (77 ± 5 vs. 157 ± 7 kJ, respectively). The eight-week training of both groups significantly increased the mean maximum strength (by 35 and 21% in groups I and II, respectively) and volume (by 17 and 9%, respectively) of the muscles trained (however, the differences between the groups with respect to these changes were nonsignificant). Group I displayed a higher increase in the blood level of creatine phosphokinase than group II, while group II showed a greater increase in the blood concentration of lactate. In contrast to group I, group II displayed a significant increase in the blood concentrations of growth hormone, insulin-like growth factor 1 (IGF-1), and cortisol. Hence, the suggestion that the secretion of metabolic hormones is triggered by a metabolic, rather than mechanical, stimulus from working muscles seems plausible.     

The effect of picolinic acid and iron ions on the proliferation of SPEV cells

The effect of picolinic acid (PA) on SPEV cell proliferation is found to be different from that on normal and virus transformed NRC cells, and on spontaneously transformed CHO cells. It is shown that SPEV cells are arrested by PA at the end of G1-phase and at the beginning of S-phase and probably in G2-phase of the cell cycle. Ferrous ions remove the G1/S block induced by PA to permit the cell transfer through S-phase. On the one hand, PA chelates ferrous ions from the cells, and on the other one it inhibits the replicative DNA synthesis. It can be suggested that PA may arrest the SPEV cell growth affecting the iron-depend stable radical formation which is introduced into the active centre of ribonucleotiDE reduCTase. This results in the lower enzyme activity.     

Properties of thermostable HtpR-mutant of Escherichia coli

A thermoresistant htpR mutant having a decreased level of proteolytic activity has been selected in E. coli strain K802 after the directed mutagenesis in vivo. The mutation results in the bacteriophage T7 RNA-polymerase stability, aminoglycosidephosphotransferase stability as well as in the decrease in the rate of proteolytic degradation of cytoplasmic proteins during the heat shock. The obtained mutant strain can, probably be used as a host for alien polypeptides production.     

Risk factors in the epidemiology of dysentery

The general tendency of a decrease in the morbidity rates of dysentery induced by Shigella sonnei and Shigella flexneri (separately) from Monday to the end of the week (Saturday-Sunday) has been revealed, and at the same time the "infection risk" for both kinds of salmonellosis has been found to fall on the last days of the week (Friday-Sunday).     

Effect of dissolved carbon dioxide on the tetracycline biosynthesis process in an industrial fermenter

The data on changes in the partial pressure of carbon dioxide (pCO2) dissolved in the fermentation broth in the course of biosynthesis of tetracycline made in a 63 m3 fermenter are presented. It is shown that pCO2 equal approximately to 2 cPa was optimal for tetracycline biosynthesis. The total carbonate concentration and pCO2 were estimated simultaneously in the process of tetracycline fermentation.     

Preparation of subtilisin BPN' and dextran conjugates

The conditions for subtilishine BPN' binding with bromocyanogen activated dextranes have been selected. The dependence of the enzyme activity and stability from pH and temperature levels has been studied. The stability of a modified enzyme during storage in solution is increased as compared with that of the native enzyme due to a decrease in the autolysis rate. On the basis of diffusion coefficients and sedimentation constants of conjugates, absolute values of their molecular weights have been computed.     

Study of toxicity and antineoplastic activity of 14-substituted derivatives of rubomycin and carminomycin

Toxicity and antitumor activity of five derivatives of rubomycin and carminomycin were studied in animals. The derivatives were prepared by modification of the methyl C-14 group. These were the following: 14-chlorrubomycin, 14-chlorcarminomycin, 14-salicyloyloxyrubomycin, 14-salicyloyloxycarminomycin and 14-quinaldinoyloxyrubomycin. The chemotherapeutic study revealed that, in their activity, all the compounds were inferior to the starting antibiotics. Unlike the other derivatives, 14-chlorcarminomycin induced a significant inhibition of leukemia P-388 development (the average lifespan of the mice amounted to 165 per cent as compared to the control). However, in the magnitude of its effect, the derivative was inferior to carminomycin.     

Effect of thymus histones on the RNAase, ATPase and phosphatase activity of staphylococcal cells]

It was shown that the representatives of different strains of Staphylococcus genus were characterized by a differential histone sensitivity. The membrane permeability increased in case of the bacterial contact with histones, and the degrading of the sum total cell RNA occurred in the contact of bacteria with histones. The RNA-ase, phosphatase, and the ATP-ase activity increased in the cells after their treatment with histones. The extent of expression of all these processes in the representatives of different strains correlated with their sensitivity to individual histone fractions. The problem that all the phenomena described indicated both the inhibitory effect of histones and some metabolic changes (permitting the cells to preserve their viability under unfavourable conditions) is discussed.