Formation of adducts of pyridine nucleotides in the active center of swine lactate dehydrogenase (isoenzyme M4)]

Isozyme M4 of pig lactate dehydrogenase (LDH-M4) catalyzes reaction of NAD-adduct formation with a nucleophylic agent that is perhaps OH--ion. The T 1/2 of the reaction is 10-30 sec at concentration NAD 2,0-10(-3) M, LDH-M4 50 gamma/ml at pH greater than 8. Initial velocity and limit of the reaction increase at high LDH-M4, NAD and OH--ion concentrations. Pyridine-3-aldehyde and 3-acetyl pyridine analogs of NAD forms fluorescent adducts too, but at OH--ion concentration approximately 0,01 of that in the case of NAD reaction. Isoelectrical point of LDH-M4 determined by isoelectrofocusing method is 8,65 +/- 0,04 pH unit.     

Antigenic structure of the foot-and-mouth-disease virus. I. Synthesis of protective peptides from the major immunogenic region of VP1 protein of foot-and-mouth virus type O1K

A series of overlapping peptides with the sequence of the immunodominant region of VP1 protein of FMDV strain O1K have been synthesized by the classical solution method. Peptides were purified by standard methods and used for immunization of guinea pigs. It is shown that the 136-152 and 136-148 segments provide antiviral protection in guinea pigs, both in the free state and conjugated with an immunogenic carrier. Results with uncoupled peptides indicated that these segments may form not only B-, but also T-cell affecting sites.     

Cytogenetic study of the mutagenicity of cucumarioside

Mutagenic activity of cucumarioside displaying strong immunomodulating effect was studied. Two cytogenetic tests--mouse bone marrow micronucleus assay and the method for analysis of chromosomal aberrations--were used to evaluate mutagenic activity. Both tests demonstrated negative mutagenic effect.     

A novel,stereospecific synthesis of β-D-glucopyranosyl phosphate

In alkaline solution, periodate ions form complexes with three consecutive hydroxyl groups in an axial-equatorial-axial arrangement but not with three syn-axial hydroxyl groups. Borate ions form complexes with three syn-axial hydroxyl groups but not with the axeqax sequence. Accordingly, cis-inositol gives a 1,2,3-periodate and a 1,3,5-borate complex. Cations form complexes with either type of conformation, but complex formation provides little energy towards achieving it by ring inversion. Lanthanide ions have been used to establish the sites of complex formation.     

Microcloning and characteristics of DNA from regions of the centromeric heterochromatin of Drosophila melanogaster polytene chromosomes]

A method of microcloning, which involves microsurgical excision of chromosome fragments, DNA amplification by means of a polymerase chain reaction (PCR), and ligation of amplified products with plasmids, was employed in studying Drosophila polytene chromosomes for the first time. Clones of the DNA library thus obtained contained inserts varying in size from 0.1 to 0.5 kb. DNA sequencing of five clones of the library showed that pericentromeric heterochromatin contained the 17.6 and 297 retrotransposons, the ninja retrotransposon characteristic of D. simulans, and two Drosophila repetitive elements, a8 and a12, the function of which remains unknown.     

Memristors: Memory elements in potato tubers

A memristor is a nonlinear element because its current-voltage characteristic is similar to that of a Lissajous pattern for nonlinear systems. This element was postulated recently and researchers are looking for it in different biosystems. We investigated electrical circuitry of red Irish potato tubers (Solanum tuberosum L.). The goal was to discover if potato tubers might have a new electrical component - a resistor with memory. The analysis was based on a cyclic current-voltage characteristic where the resistor with memory should manifest itself. We found that the electrostimulation by bipolar sinusoidal or triangle periodic waves induces electrical responses in the potato tubers with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K⁺ channels, transforms a memristor to a resistor in potato tubers. Our results demonstrate that a voltage gated K⁺ channel in the excitable tissue of potato tubers has properties of a memristor. Uncoupler carbonylcyanide-4-trifluoromethoxy-phenyl hydrazone decreases the amplitude of electrical responses at low and high frequencies of bipolar periodic sinusoidal or triangle electrostimulating waves. The discovery of memristors in plants creates a new direction in the understanding of electrical phenomena in plants.     

The influence of mast cells on reparative regeneration of tissues characterized by various degrees of immune privilege

Tissues characterized by various degrees of immune privilege are thought to differ in repair processes. This circumstance may be due to mast cells (MCs) that occur in all tissues of the body, secrete a wide range of biologically active compounds, and play an important role in the regulation of repair processes. The present paper reports the results of investigations of morphometric parameters and functional activity of MCs in tissues characterized by various degrees of immune privilege such as the skin and testis. It was shown that MCs migrate into the skin in the early stages after damage, followed by a slow increase in the synthetic activity and degranulation index of MCs for 30 days. In the case of the testis, the MC degranulation index increases immediately after damage, with a pronounced migration of MCs being absent. The stabilization of MC membranes with ketotifen inhibits skin repair; namely, there is no increase in the thickness of the dermis and epidermis and the number of fibroblasts and collagen fibers, along with slowing down of the scar formation. Meanwhile, the MC inactivation contributes to the reparative regeneration of the testis. This circumstance is confirmed by a significant reduction of the number of nonfunctioning tubules and an increase in the number of normal spermatogonia, which are a proliferative pool for all subsequent stages of spermatogenesis. Thereby, the number and the functional state of MCs influences the repair processes in tissues characterized by various degrees of immune privilege.     

The effect of intra-articular emoxipin injections on the course of immune arthritis in rabbits]

Immune arthritis in sensitized rabbits was induced by intraarticular injection of bovine serum albumin. The development of the arthritis was accompanied by an increase in ESR, a rise of the level of serum CRP, caeruloplasmin and CIC. A chemiluminescent response of the whole blood phagocytes to stimulation by barium sulfate crystals, serum beta-glucuronidase and red cell superoxide dismutase activity enhanced, plasma malone dialdehyde content rose, serum SH groups diminished.