Microbiota and Paleoenvironments of the Turtas Paleobasin,Late Oligocene,Western Siberia

The Turtas Formation (the Upper Oligocene of Western Siberia), uncovered by the Zyryanka-1 Borehole, contain diverse assemblage of microfossils. The ecological composition (freshwater diatoms, spicules and gemmuloscleres of freshwater sponges, spores and pollen, as well as zygospores of Zygnematales algae) indicates the nonmarine nature of the Early Turtas Basin. In contrast to the assemblage of the Zhuravka horizon (southern regions of Western Siberia), the absence of Fagaceae and dinocysts of the genus Pseudokomewuia, as well as low numbers of Taxodiaceae–Cupressaceae and Betulaceae, are probably explained by local characteristics.     

Isolation and analysis of Ca/Mg-dependent endonuclease from cell nuclei of human splenocytes

A scheme for the isolation of Ca,Mg-dependent endonuclease from human spleen lymphocyte nuclei has been developed. The isolation procedure resulted in protein preparations (Mr = 57 kD) possessing an enzymatic activity and stable upon storage for over a period of one year. The enzyme is an endonuclease which predominantly cleaves double-stranded DNA by a mixed single- and double-hit mechanism with the formation of 5'-phosphate and 3'-OH terminal groups. Its maximal activation is induced by Ca2+ plus Mg2+. The enzyme is also active in the presence of Mn2+, Ca2+, Mg2+ and Zn2+ and is inhibited by Co2+. NaCl and KCl (0.15-0.2 M) and p-chloromercuribenzoate (1 mM) also inhibit the enzyme. ATP has no activating effect.     

PEGylated recombinant L-asparaginase from <Emphasis Type="Italic">Erwinia carotovora</Emphasis>: Production,properties, and potential applications

N-hydroxysuccinimide ester of monomethoxy polyethylene glycol hemisuccinate was synthesized. It acylated amino groups in a molecule of recombinant L-asparaginase from Erwinia carotovora. A method of L-asparaginase modification by the obtained activated polyethylene glycol derivative was developed. The best results were produced by modification of the enzyme with a 25-fold excess of reagent relative to the enzyme tetramer. The modified L-asparaginase was isolated from the reaction mixture by gel filtration on Sepharose CL-6B. The purified bioconjugate did not contain PEG unbound to the protein, demonstrated high catalytic activity, and exhibited antiproliferative action on cell cultures.     

Contact interactions of spreading thrombocytes

Contact interactions of rabbit platelets was studied in the course of their spreading over the siliconized glass surface. When the density of cells adhered to the substratum surface is high enough, the platelets are spreading in such a way that their edges are in a close proximity, while the overlapping of cells is very rare and scarcely pronounced. A morphometric analysis of the probability of such an organization of platelets at their random and independent disposition on the substratum proves the existence of a contact inhibition of platelets spreading on the substratum. Thus, a phenomenon of the contact inhibition seems to be a common feature not only of large nucleated cells but also of small anuclear platelets.     

A neurophysiologic analysis of the effect of amidopyrine at the thalamo-cortical level of the somatosensory system]

Acute experiments were conducted on nonanesthetized cats; it was shown that amidopyrin (10, 20 mg/kg, intravenously) decreased the level of the background activity of the thalamic neurons, and, at the same time, increased the amplitude of the focal primary bioelectrical reactions. It is supposed that amidopyrin synchronized evoked reactions of the cells in the thalamus, as well as in the cortex. On the other hand, amidopyrin diminished the excitability of the cortical neurons participating in the interzonal connections.     

The experiment “initial stages of biological damage and deterioration in space”

A study of the microflora of structural surfaces on board the russian segment of the international space station (RS ISS) has demonstrated that the species composition that is formed during the mission is similar to that on board the mir station. the microflora of the sampled sites was similar to that of residential and industrial buildings on earth. it was represented by 17 species of fungi, seven genera of bacteria, and three genera of actinomycetes. the degree of colonization of the surfaces of structural materials of the rs iss by destructive microorganisms was low and showed undulating dynamics. the mycelial fungi included “technophile” species, which caused biological corrosion of an aluminum-magnesium alloy in simulation experiments.     

Silver-Containing Humic Substance-Based Nanocomposites—Agents for Healing of Potatoes from the Ring Rot

The influence of silver-containing humic substance (HS)-based nanocomposites (NCs) obtained from mud, shale, and coals of three kinds of deposits in Mongolia on the viability and ability to biofilm formation of a phytopathogenic gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus (Cms), as well as peroxidase activity and potato plant growth in vitro, has been investigated. The maximum reduction of the viability of bacterial cells was found in the case of incubation with HS-mu/Ag NC and HS-coal/Ag NC. It was found that HSs, including HS-mu and HS-sl, and NCs synthesized on the base of these HSs, HS-mud/Ag NC and HS-sl/Ag NC reduce more than twofold the activity of peroxidase in potato tissues. It was also found that HS-co and HS-coal/Ag NC stimulate the potato peroxidase activity, as well as biofilm formation of Cms bacterium. No negative effect of the studied NCs on the growth of potato has been revealed. Moreover, NC HS-mud/Ag based on mud had a stimulating effect on leaf formation in plants.