Structural transformations of arabinogalactan from the Siberian larch during mechanochemical processing and the biological properties of the products

It has been found by gel-penetrating chromatography and quantitative ¹³C NMR spectroscopy that mechanochemical processing of arabinogalactan isolated from the wood of the Siberian larch changes the molecular mass distribution, monosaccharide composition, and the degree of branching of its macromolecules. This is due to the partial destruction of polysaccharide macromolecules and subsequent recombination of resulting fragments. The intensity of these processes depends on the conditions of mechanochemical processing. Based on the data of IR and ¹³C NMR spectra, the conclusion has been drawn that no functionalization of arabinogalactan macromolecules occurs under these conditions. The toxicopharmacological properties of mechanically processed arabinogalactan have been studied. Its acute toxicity is >5000 mg/kg.     

Quantitative characteristics of radiation injury of the spermatogenic epithelium and the rate of its recovery after exposure to fast neutrons and gamma-radiation

The paper submits the results of studies on the kinetics of spermatogenous epithelium cell number after exposure to fast neutrons (60-300 cGy) and gamma-radiation (200-600 cGy). It was shown that a relative decrease in the quantity of spermatocytes is determined by an exponential dose-response curve with D0 of 35 and 120 cGy for neutrons and gamma-radiation respectively. For spermatides and spermatozoa a single D0 value of 20 and 55 cGy was obtained for neutrons and gamma-radiation respectively. As the radiation dose increases the recovery process in the epithelium is substantially decelerated. The equation T1/2 = T1/2(0)e0.0009D well describes the dependence of the half-recovery period T1/2 upon the equivalent dose.     

Enzymatic System of Metabolism and Detoxication of Xenobiotics as a Basis of Metabolic Portraiting during Prognostication of Risk of Pathological Processes

We studied intraspecific features of the main enzymes of metabolism and detoxication of xenobiotics on mice (eight inbred lines) and rats (five lines) for estimation of possible variants of complete or incomplete metabolic equality. Significant genetically determined intraspecific differences for activities of the enzymes of metabolism and detoxication of xenobiotics were described. Generalized criteria for comparison of the metabolic status were proposed on the basis of activities of the main enzymes: cytochrome P-450 (hydroxylation and epoxidation), epoxyhydrolase, glutathione-S-transferase, UDP-glucuronosyl transferase, and sulfotransferase. The proposed criteria for estimation of the metabolic parameters of an individual can serve as a basis of metabolic portraiting.     

Composition and structure of the antibiotic polypeptide 308-I from Actinomadura recticatena

Antibiotic 308-I isolated from Actinomadura recticatena and the products of its degradation were studied with the methods of electron impact mass spectrometry, chemical ionization with ammonia, field desorption and ion extraction from solution under atmospheric pressure. It was shown that by its composition and structure antibiotic 308-I was identical to antibiotic BBM-928 A.     

Acoustic orientation of male Aedes diantaeus during mating

The reaction of males of Aedes diantaeus to different auditory stimuli was studied in natural environment during swarming and under laboratory conditions. The males were attracted by 250-420 Hz that corresponds to the main frequencies of flight tones of sympatric females and the range of sensitivity of male Johnston's organs. Behavioural data show that in natural environment swarming males are attracted by flying conspecific and heterospecific females rather than by dead or immobilized females. Contact with heterospecific females always ended in parting of mosquitoes while contact with cospecific females resulted in pairing. Thus, swarming males of Aedes diantaeus localize females by their flight tones but recognize the females of their own species in contact.     

Recombinant plasmids carrying multiple markers: isolation during yeast co-transformation

Cotransformants of yeast cells by two partially homologous plasmids, one of which is incapable of autonomous replication, has been used to construct multiply marked recombinant plasmids. Only simultaneous elimination of three yeast markers was registered when episomal plasmid, carrying Ade2 gene, and integrative plasmid, carrying yeast genes LEU2 and URA3, were cotransformed. Transformants, in which yeast genes LEU2, URA3 and HIS3 are linked, have been isolated by analogous technique. The genetic analysis has confirmed existence of plasmid cointegrates in the transformant cells, which carry three yeast genes, bacterial DNA fragment and 2 micrometers DNA fragment, coding for replicative functions. Recombination in the region of bacterial plasmid pBR322 might have resulted in formation of such plasmids. Plasmid recombination in cotransformants has been used to construct multiply marked circular chromosomes, having included yeast genes LEU2, URA3 and TRP1, centromere of the IV yeast chromosome and the sequence coding for their replication in yeast as well as in E. coli cells.     

Isozymes of NADP-dependent isocitrate dehydrogenase in normal and tumor tissues of various mouse strains and their hybrids

Normal tissues of DBA, CBA, CC57W, C3H, Balb/c, SHR mice and F1 hybrids CC57W/DBA appeared to differ in the ratios of mitochondrial and supernatant NADP-dependent isocitrate dehydrogenase (IDH). Tested inbred mice strains CC57W, C3H, SHR, Balb/c contain allelic form Idh-1a of supernatant IDH gene Idh-1, whereas allelic form Idh-1b is characteristic of mice strains DBA and CBA. In tumors IDH isozymes have the same mobility as do isozymes of homologous normal tissues; but their activity is lower. A high variability of each isozyme activity in the isozyme spectrum is revealed in various tissues of F1 hybrids CC57W/DBA. Allelic forms of gene Idh-1 were used as markers of normal and tumor cells for the experimental model: transplantation of sarcoma 37 (Idh-1a/Idh-1a) to subcutaneous tissue of the mouse strain DBA (Idh-1b/Idh-1b). It enables us to reveal isozymes of stromal cell in tumor IDH isozyme spectrum. The results indicate that the relation of normal and tumor isozymes vary in different tumors.     

Effects of phenazepam and aliphatic alcohols on epileptic complex created in the rat brain cortex

Effects of phenazepam and aliphatic alcohols (methanol, ethanol, butanol, and propanol) on associated epileptic complex created in the rat brain cortex by applications of strychnine were studied. Phenazepam considerably suppressed the epileptic foci and their complexes in a dose-dependent manner. A comparison of anticonvulsive effects in a series of aliphatic alcohols methanol-ethanol-propanol-butanol showed that all these substances are potent anticonvulsants. Propanol and butanol reduce epileptic seizures most intensively, but, at the same time, they are most toxic. Application of labelled⁴C-ethanol showed that anticonvulsive effects strongly correlate with changes in the ethanol concentration in the blood.Neirofiziologiya/Neurophysiology, Vol. 26, No. 6, pp. 443–448, November–December, 1994.