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.     

Isolation and comparative analysis of multiple isoenzymes of glutathione-S-transferase from the liver of intact rats and rats administered phenobarbital, 3-methylcholanthrene and butylhydroxytoluene

Seven glutathione-S-transferase (GST) isozymes were purified from liver cytosol of intact male Wistar rats: 1-1(A), 1-1(B), 1-2, 2-2, 3-3, 3-4, 4-4. Treatment of rats with butylated hydroxytoluene (BHT) led to the induction of isozymes GST 1-1(A), 1-1(B) (2-fold), 3-3 (3.5-fold) as well as to the appearance of two new isozymes--1-3 and 4-4(A). Phenobarbital (PB) induced isozymes GST 1-1(A), 1-1(B) (2-fold) and 3-3 (1.5-fold). BHT and PB caused an increase in the specific activity of isozymes 1-1(A), 1-1(B), 3-3, 3-4 towards 1-chloro-2.4-dinitrobenzene and 1.2-dichloro-4-nitrobenzene. 3-Methylcholanthrene (MC) induced isozymes 1-2 (1.5-fold), 2-2 (2-fold) and 4-4 (3-fold). A conclusion was drawn that BHT and PB induced the GST subunits 1 and 3, whereas MC--subunits 2 and 4.     

A Critical Point of Male Gonad Development: Neuroendocrine Correlates of Accelerated Testicular Growth in Rats during Early Life

Testis growth during early life is important for future male fertility and shows acceleration during the first months of life in humans. This acceleration coincides with the peak in gonadotropic hormones in the blood, while the role of hypothalamic factors remains vague. Using neonatal rats to assess this issue, we found that day 9 of life is likely critical for testis development in rats. Before this day, testicular growth was proportional to body weight gain, but after that the testes showed accelerated growth. Hypothalamic kisspeptin and its receptor mRNA levels begin to elevate 2 days later, at day 11. A significant increase in the mRNA levels for gonadotropin-releasing hormone (GnRH) receptors in the hypothalamus between days 5 and 7 was followed by a 3-fold decrease in GnRH mRNA levels in this brain region during the next 2 days. Starting from day 9, hypothalamic GnRH mRNA levels increased significantly and positively correlated with accelerated testicular growth. Triptorelin, an agonist of GnRH, at a dose that had no effect on testicular growth during “proportional” period, increased testis weights during the period of accelerated growth. The insensitivity of testicular growth to GnRH during “proportional” period was supported by inability of a 2.5-fold siRNA knockdown of GnRH expression in the hypothalamus of the 7-day-old animals to produce any effect on their testis weights. GnRH receptor blockade with cetrorelix was also without effect on testis weights during “proportional” period but the same doses of this GnRH antagonist significantly inhibited “accelerated” testicular growth. GnRH receptor mRNA levels in the pituitary as well as plasma LH concentrations were higher during “accelerated” period of testicular growth than during “proportional” period. In general, our data defined two distinct periods in rat testicular development that are primarily characterized by different responses to GnRH signaling.     

Delayed effect of prenatal exposure to hypoxia on the susceptibility of rats to electric seizures

We studied the delayed effects of prenatal exposure to hypoxia on the susceptibility of rats to seizures. The later was estimated using graded electroshock. The experiments were performed in two groups of 1.5-year-old male Wistar rats. The experimental group consisted of the animals that were exposed to hypoxia on day 14 of prenatal development, and the control group consisted of the animals that developed under the normal conditions. In the rats subjected to prenatal hypoxia, seizure episodes induced by weak currents in the range of 10–40 mA and their average duration were more pronounced as compared to the control animals.     

On the existence of a gradient of sensitivity to the lack of sodium in the spinal roots of the bullfrog

The Et class of fibers includes fibers of Gasser's d.r. C group. The fibers of the dorsal root are more sensitive to the effect of lack of sodium than are the fibers of the ventral root. In the two roots there is a gradient of sensitivity to the lack of sodium, which is such that in all the root fibers the sensitivity decreases with increasing distance from the spinal cord. The gradient continues in the trunk up to about 10 to 12 mm. peripheral to the trunk-roots margin. No comparable gradient of sensitivity to the lack of sodium has been observed in the rest of the nerve trunk. The gradient of sensitivity to the lack of sodium has no relationship to the anatomical distribution of the epineurium. As a working hypothesis it is suggested that the gradient of sensitivity to the lack of sodium is one aspect of a transitional gradient that serves to establish a gradual change between the properties that the axons have inside the spinal cord and the properties that they have inside the nerve trunks. Details are given of the temporal course of the loss of excitability by root fibers deprived of sodium. It is suggested that sodium is present in the nerve fibers, in 2 forms, loosely and tightly bound sodium and that loss of loosely bound sodium is sufficient to render the nerve fibers unable to conduct impulses. If the rate of loss of loosely bound sodium is decreased, conversion of tightly bound into loosely bound sodium may temporarily restore the excitability of the nerve fibers.     

Design of a PCR test based on the gyrA gene sequence for the identification of closely related species of the Bacillus subtilis group

A method for the taxonomic identification of seven closely related bacterial species of the Bacillus subtilis group (B. subtilis, B. amyloliquefaciens, B. licheniformis, B. vallismortis, B. atrophaeus, B. sonorensis, and B. mojavensis) using specific primers selected on the basis of the gyrA gene sequences was developed. The effectiveness of this method both for the identification of pure cultures of type strains of this group and for the precise species identification of collection and industrial bacterial strains was demonstrated. The principal possibility of using this method for detecting B. subtilis group bacteria in mixed cultures was shown.     

Molecular Analysis of Leaf Rust-Resistant Introgression Lines Obtained by Crossing of Hexaploid Wheat Triticum aestivum with Tetraploid Wheat Triticum timopheevii

Twenty-four Triticum aestivum×T. timopheevii hybrid lines developed on the basis of five varieties of common wheat and resistant to leaf rust were analyzed by the use of microsatellite markers specific for hexaploid wheat T. aestivum. Investigation of intervarietal polymorphism of the markers showed that the number of alleles per locus ranged from 1 to 4, depending on the marker (2.5 on average). InT. timopheevii, amplification fragments are produced by 80, 55, and 30% of primers specific to the A, B, and D common wheat genomes, respectively. Microsatellite analysis revealed two major areas of introgression of the T. timopheevii genome: chromosomes of homoeological groups 2 and 5. Translocations were detected in the 2A and 2B chromosomes simultaneously in 11 lines of 24. The length of the translocated fragment in the 2B chromosome was virtually identical in all hybrid lines and did not depend on the parental wheat variety. In 15 lines developed on the basis of the Saratovskaya-29, Irtyshanka, and Tselinnaya-20, changes occurred in the telomeric region of the long arm of the 5A chromosome. Analysis with markers specific to the D genome suggested that introgressions of the T. timopheevii genome occurred in chromosomes of the D genome. However, the location of these markers on T. timopheevii chromosomes is unknown. Our data suggest that the genes for leaf rust resistance transferred from T. timopheevii to T. aestivum are located on chromosomes of homoeological group 2.