Effects of phospholipase A2 and alpha-tocopherol on the activity of adenylate cyclase of rat brain synaptosomes

The action of phospholipase A2 and alpha-tocopherol on adenylate cyclase system functioning and on the lipid bilayer microviscosity of the rat brain synaptosome membranes was investigated. It was shown that the exposure of the synaptosomes to phospholipase A2 increases the adenylate cyclase activity stimulated by guanylyl imidotriphosphate (GITP), decreases the adenylate cyclase activity stimulated both by isoproterenol and by isoproterenol with GITP. The preincubation of synaptosomes in medium containing alpha-tocopherol does not change the character of the phospholipase action on the adenylate cyclase activity stimulated by isoproterenol but normalizes the adenylate cyclase activity stimulated both by GITP and by GITP with isoproterenol. In the last case the normalizing action of alpha-tocopherol is not caused by alteration of the microviscosity of the lipid bilayer. It appears to be due to the modification of the lipid-protein interactions of annular lipids with activated complex of catalytic subunit and guanyl nucleotide-binding protein.     

Cytogenetic Analysis of Spermatozoa in a Patient with Chromosome Constitution 45,X/46,X,r(Y) by Intracytoplasmic Injection into Mouse Oocytes

The chromosome set of human spermatozoa was studied by intracytoplasmic injection into mouse oocytes. A total of 85 metaphase plates of male pronuclei of a patient with chromosome constitution 45,X/46,X,r(Y) and 108 metaphase plates of patients with normal sperm parameters (control group) were examined. The ratio between X- and Y-bearing chromosomes in the 45,X/46,X,r(Y) patient and in the control group did not differ from 1 : 1. A significant increase in the rates of diploidy, hypoploidy, hyperploidy of sex chromosomes, and chromosome structure rearrangements in spermatozoa of the patient in comparison with spermatozoa in the control group was recorded.     

DNA-binding and Oxidative Properties of Cationic Phthalocyanines and Their Dimeric Complexes with Anionic Phthalocyanines Covalently Linked to Oligonucleotides

Abstract

Design of chemically modified oligonucleotides for regulation of gene expression has attracted considerable attention over the past decades. One actively pursued approach involves antisense or antigene oligonucleotide constructs carrying reactive groups, many of these based on transition metal complexes. The complexes of Fe(II) and Co(II) with phthalocyanines are extremely good catalysts of oxidation of organic compounds with molecular oxygen and hydrogen peroxide. The binding of positively charged Fe(II) and Co(II) phthalocyanines with single- and double-stranded DNA was investigated. It was shown that these phthalocyanines interact with nucleic acids through an outside binding mode. The site-directed modification of single-stranded DNA by O₂ and H₂O₂ in the presence of dimeric complexes of negatively and positively charged Fe(II) and Co(II) phthalocyanines was investigated. These complexes were formed directly on single-stranded DNA through interaction between negatively charged phthalocyanine in conjugate and positively charged phthalocyanine in solution. The resulting oppositely charged phthalocyanine complexes showed significant increase of catalytic activity compared with monomeric forms of phthalocyanines Fe(II) and Co(II). These complexes catalyzed the DNA oxidation with high efficacy and led to direct DNA strand cleavage. It was determined that oxidation of DNA by molecular oxygen catalyzed by complex of Fe(II)-phthalocyanines proceeds with higher rate than in the case of Co(II)-phthalocyanines but the latter led to a greater extent of target DNA modification.     

The indices of systemic and regional hemodynamics in waking rats with streptozotocin diabetes]

Important cardiovascular dysfunctions have been described in streptozotocin (STZ)-diabetic rats. To determine the influence of these changes on the hemodynamic state, the different hemodynamic parameters, obtained by microsphere technique, were studied in STZ-induced (50 mg/kg) diabetic male Wistar rats, as well as in age control. All the rats were examined in the conscious, unrestrained state 12 weeks after induction of diabetes or acidified saline (pH 4.5) injection. During 12 weeks of the diabetic state the most important findings are hypotension, increase in cardiac index, decrease in total peripheral resistance and altered regional blood flow. These results suggest that important hemodynamic alterations are present in the chronic diabetic state.     

25-Hydroxycholesterol as a Signaling Molecule of the Nervous System

Biochemistry (Moscow) - Cholesterol is an essential component of plasma membrane and precursor of biological active compounds, including hydroxycholesterols (HCs). HCs regulate cellular homeostasis...     

Interconnection between parameters of motor activity and blood glucose concentration in newborn rats at starvation and under glucose load conditions

The study is carried out on the one-, 3-, 5-, 7, and l0-day old free moving or loosely fixed rat pups (P1–10). In satiated and submitted to the 24-h starvation rat pups, parameters of spontaneous periodical motor activity (SPMA) and the blood glucose content were determined. The total glucose level in hungry rat pups was, on average, 1.5–2.5 times lower than in satiated animals. Administration of glucose to hungry rat pups increased 6–11 times its concentration in blood as compared with the animals not obtaining glucose. The glucose administration to the satiated rat pups led to a rise of its level in blood from 2 to 5 times as compared with intact animals, which was 2–3 times less than in the case of hungry animals. Analysis of pattern of motor activity recorded under conditions of the glucose deficit caused by the 24-h starvation of rat pups did not reveal significant changes of ratio of rhythmical components. Introduction of glucose to hungry and to the lesser degree to satiated rat pups led to potentiation of the minute rhythm of activity in all age groups. The exception was the first day after birth when the glucose administration to satiated rat pups promoted an enhancement of the decasecond rhythm and a decrease of the total level of motor activity. Comparison of ontogenetic dynamics of the SPMA parameters and the glucose content in blood of hungry rat pups revealed the clearly expressed regularity absent in the satiated animals: the glucose level in blood was higher during activity than in the state of rest. The performed study has shown that intensity, duration, and, to a degree, pattern of SPMA in the newborn rat pups depend on the level of satiety, and can be significantly changed in the artificially produced hypo- or hyperglycemia. The existing ontogenetic fluctuations in the character of reaction at performance of the glucose tolerance test can be connected both with morphofunctional maturation of the motor system and with immaturity of various chains of carbohydrate metabolism.     

Speciation in status nascendi in Siberian Crabapple Malus baccata (L.) Borkh

Molecular genetic and morphometric studies of the tall and dwarf forms of the Siberian crabapple, which grow on the territory of Buryatia, were carried out. A phylogenetic analysis based on six highly polymorphic microsatellite loci showed that the dwarf form descends from the tall forms of Malus baccata and both studied forms belong to the same species of Siberian crabapple. Based on the obtained data, we propose that the dwarf form is an ecological form of the Siberian crabapple and possibly represents an initial stage of parapatric speciation.