Quantitative estimation and forecast of biomasses of hydrobionts’ ecological groups with use of determination analysis

By means of determination analysis, optimum values of phytoplankton biomass and its divisions are calculated. These values provide development of high biomass of such primary consumers as zooplankters. It is shown that representatives of Rotatoria have higher levels of optimum biomass than Crustacea. In the Kara region it is possible to ascertain the increase of such levels for Cladocera in comparison with Copepoda. The prediction of zooplankton communities’ development is carried out using values of optimum biomass of phytoplankton. Accuracy of the forecast in the Azov area is highest, i.e., quantitative requirements of zooplankton for fodder phytoplankton here are poorly subject to variability in time.     

Studies of hydrolytic activity of enzyme preparations of <Emphasis Type="Italic">Penicillium</Emphasis> and <Emphasis Type="Italic">Trychoderma</Emphasis> fungi

Enzyme preparations were isolated from the culture liquid of five mutant strains of the cellulase producer Penicillium verruculosum. The hydrolytic activities of these preparations against unbleached eucalypt cellulose was compared to that of commercial preparations of Trichoderma reesei (T. longibrachiatum). In the majority of cases, P. verruculosum enzymes provided higher yields of reducing sugars (RSs) and glucose. A correlation was found between the yield of RSs and the avicelase activity of the preparations in the reaction mixture.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 2, 2005, pp. 210–212.Original Russian Text Copyright © 2005 by Skomarovsky, Gusakov, Okunev, Soloveva, Bubnova, Kondrateva, Sinitsyn.     

Model of radiation-accelerated aging and its specific features

We conducted a lifetime study of the content of oxidized and methylated guanine in the urine of intact and irradiated mice. For statistical processing of the results, we used the trial period method created by A.A. Konradov, which was unpublished during the author’s lifetime. We prove that there are oscillating components in the age dependence of the concentration of oxidized and methylated guanine in mice urine. For intact animals, a 7-month oscillation period is the most probable (p = 0.001). For irradiated mice, a disruption in the seasonal oscillation rhythm in the concentration of oxidized and methylated guanine in urine was noted, which is peculiar to radiation-accelerated aging.     

Determination of binding constants of lipopolysaccharides of different structure with chitosan

The interaction of endotoxins--lipopolysaccharides (LPS) different in degree of the O-specific chain polymerization--with 20- and 130-kD chitosan was studied using the competitive binding of LPS with the complex of chitosan-anionic dye (tropaeolin 000-2) and the direct binding of (125)I-labeled LPS with chitosan immobilized on Sepharose 4B. The interaction of 20-kD chitosan with LPS was non-cooperative, and immobilization of the polycation on Sepharose resulted in its binding to (125)I-labeled LPS with a positive cooperativity. The interaction of LPS possessing a long O-specific chain with 130-kD chitosan was characterized by negative cooperativity. Binding constants of LPS with the polycation and the number of binding sites per amino group of chitosan were determined. The interaction affinity and stoichiometry of the LPS-chitosan complexes significantly depend on the LPS structure and concentration in the reaction mixture. The increase in the length of carbohydrate chains of LPS results in increase in the binding constants and decrease in the bound endotoxin amount.     

Effects of nitric oxide and hypoxia on low-and high-voltage activated calcium currents in murine DRG neurons

The effects of a nitric oxide (NO)-containing aqueous solution (authentic NO) and hypoxia on low-and high-voltage activated calcium currents (I _Ca,lva andI _Ca,hva , respectively; in the latter transient and sustained portions were differentiated) were studied in enzymatically dispersed medium-sized neuronal somata from the murine dorsal root ganglia (DRG). Authentic NO (10 μM) was found to decrease the mean peak amplitude ofI _Ca,lva , from 3.5±0.3 to 1.2±0.2 nA (n=11,p<0.001), as well as the amplitudes of transient and sustainedI _Ca,hva components from 4.5±0.1 to 2.7±0.2 nA and form 2.8±0.2 to 1.7±0.2 nA (n=11;P<0.001), respectively. This NO-induced suppression was reversible and was removed by 1-min-long washout. At the same time, medium-sized DRG neurons demonstrated relatively low sensitivity to hypoxia (P_O2=20–25 mm Hg): decreases of both types ofI _Ca under hypoxic condition were not statistically significant (n=11;p>0.05). The data strongly suggest that NO is capable of reversibly suppressing both types of calcium channels in murine DRG neurons and of modulating in this way their excitability. It seems likely that this ability is based on a direct effect of NO on the corresponding channels and not on NO participation in the induction of hypoxic effects. Yet, a hypothesis that NO is a messenger of hypoxic damage to neural cells still should be suggested.     

Diversity of microbial communities of the intestinal mucosa and intestinal contents of fish from Lake Chany (Western Siberia)

The diversity of microbial communities associated with the intestinal mucosa and the intestinal contents of fish with different nutritional profiles have been investigated. Differences in the intestinal microbiota of fish with different dietary preferences have been revealed using group-specific primers for the main large taxa of bacteria. Representatives of the phyla Planctomycetes, Vernicomicrobia, and Cyanobacteria have been detected in the intestinal contents of all investigated nonpredatory (crucian carp, roach, and dace) and predatory (pikeperch, pike, and perch) fish. Representatives of the phylum Firmicutes were detected in the intestinal mucosa and intestinal contents of predatory fish species, but not in those of the nonpredatory fish.     

Freezing of dehydrated calli of spring wheat (<Emphasis Type=Italic>Triticum aestivum</Emphasis> L.) in liquid nitrogen and their morphogenetic potential

A cryopreservation method developed earlier was modified for freezing of calli derived from mature embryos of four spring wheat (Triticum aestivum L.) pure lines. The effects of particular stages of cryopreservation protocol on water content, number of calli recovering growth, and rate of morphogenesis were analyzed. Regrowth was observed in 90.5–100% of calli after dehydration and in 93.3–100% after freezing-thawing. Dehydration, but not freeze-thawing significantly decreased the frequency of morphogenetic variation.     

Marine invertebrates of the Sea of Okhotsk as a new source of lypopolysaccharide-binding proteins

Invertebrates from the Sea of Okhotsk were studied as a source of proteins that are capable of binding to lipopolysaccharides (LPSs) of gram-negative bacteria. A DOT analysis using dansyl-labeled LPS that we developed revealed LPS-binding proteins in blood-cell lysates of 21 out of 33 investigated species of invertebrates. Most of the investigated species with positive LPS-binding activity were decapod crustaceans (class Malacostraca, phylum Arthropoda). Hemocyte lysates from the red king crab Paralithodes camtschaticus and the sculptured shrimp Sclerocrangon boreas contained several LPS-binding proteins with different molecular weights. LPS-binding proteins were found for the first time in echinoderms (classes Holothuroidea, Asteroidea, and Echinoidea), sipunculans, and brachiopods.     

Influence of gold nanoparticles on activation of human blood neutrophils

Activation of neutrophils in the presence of gold nanoparticles is accompanied by formation of free-radical peroxidation products, recorded as a flash of chemiluminescence. The basis for the activation mechanism has its origins most likely in the influence of the gold particles on the membrane surface potential of neutrophils. Assessment of changes in the fluorescence intensity of the negatively charged ANS probe on the surface of model membranes upon adding different concentrations of gold nanoparticles indicates a change in the membrane surface charge density, which can cause cell activation.