Synthetic polymeric sialoside inhibitors of influenza virus receptor-binding activity.

Anomeric aminobenzylglycosides of Neu5Ac were coupled with the polyacrylate carrier and a number of synthetic polyvalent sialosides obtained were investigated as inhibitors of influenza virus attachment. The inhibitory activity of polymeric sialosides is highly dependent upon the Neu5Ac residue content and the nature of the carrier. The polyacrylic acid based polymer bearing 10 mol% of Neu5Ac is 3 orders of magnitude more potent inhibitor than the corresponding monovalent benzylsialoside and considerably more active than fetuin.     

Role of tumor necrosis factor alpha and sphingomyelin cycle activation in the induction of apoptosis by ischemia/reperfusion of the liver

The signal transduction pathways triggering apoptotic mechanisms after ischemia/reperfusion may involve TNF- secretion, ceramide generation, and initiation of lipid peroxidation. In the present study involvement of the TNF-, sphingomyelin cycle, and lipid peroxidation in the initiation of apoptosis induced in liver cells by ischemia and reperfusion was investigated. Wistar rats were subjected to total liver ischemia (for 15, 30 min, and 1 h) followed by subsequent reperfusion. Ischemia caused sharp decrease of neutral sphingomyelinase activity. Activity of acidic sphingomyelinase initially decreased (during 15-30 min ischemia) but then increased (after 1 h of ischemic injury). Reperfusion of the ischemic lobe of the liver caused increase in neutral sphingomyelinase activity and decrease in acidic sphingomyelinase activity. A small amount of TNF- detected by immunoblotting analysis was accumulated in the ischemic area of liver rapidly and the content of this cytokine dramatically increased after the reperfusion. TNF- is known to induce free radical production. We found that the accumulation of TNF and increase of sphingomyelinase activity during the development of ischemic/reperfusion injury coincided with increase in content of lipid peroxidation products (conjugated dienes) and DNA degradation detected by gel electrophoresis. Recently it was shown that superoxide radicals are used as signaling molecules within the sphingomyelin pathway. This suggests the existence of cross-talk between the oxidation system and the sphingomyelin cycle in cells, which may have important implications for the initial phase and subsequent development of post-ischemic injury.     

R-phycoerythrin: a natural ligand for detoxifying cadmium ions and a tunnel matrix for synthesis of cadmium sulfide nanoparticles

As evidenced by ion-selective electrode potentiometry, the hexameric R-phycoerythrin (RPE) molecule binds 20-4000 cadmium ions (Cd2+) depending on Cd2+ concentration in the solution. Cadmium ions bound to RPE serve as nuclei of cadmium sulfide crystallization in the presence of sulfide ions. According to spectrometric, electron-microscopic and capillary electrophoresis data, the particles are heteroaggregates of 3.2 x 6 nm in size. The fact that the particle size fits the size of the central tunnel of the RPE molecule and the similarity between the electrophoretic patterns of free RPE and the RPE-CdS complex indicate that the tunnel space, limiting the crystal growth, is the most probable site of nanoparticle formation. Properties of the nanoparticles can be modified by changing temperature, pH, etc. It is concluded that RPE can be used as a reagent for detoxification of cadmium ions and a matrix for synthesis of elongated CdS nanoparticles.     

Changes in the vegetation cover of cape Ostrovnoy (Gulf of Tauisk, the Sea of Okhotsk) under the influence of colonial seabirds

Changes in the vegetation on Ostrovnoy peninsula, with its large rookery of sea birds, are described. The number of birds has increased substantially since the early 1990’s. The most striking effect caused by the birds occurred in the middle of the 2000’s, which resulted in the disappearance of about ten species of flora, while a dry grass meadow was replaced by an ornithogenic reedgrass-wormwood meadow. At present the effects of the birds is somewhat weakened, and changes in the composition of vegetation have slowed down; partial recovery of the grass covering on previously distorted regions is being observed. The equilibrium of the “island” ecosystem is disturbed. Further processes that will take place in the vegetation cover are as yet unpredictable and depend first of all on the dynamics of the bird population.     

The organization of the muscle system of the causative agent of dicrocoeliosis,Dicrocoelium dendriticum

The musculature of parasitic flatworms plays a central role in locomotory movement, attachment to the host, and in the function of the digestive, reproductive, and excretory systems. We examine for the first time the muscle system of the flatworm Dicrocoelium dendriticum, a causative agent of the parasitic disease dicrocoeliosis, by use of fluorescently labeled phalloidin and confocal laser scanning microscopy. Somatic musculature of D. dendriticum consists of the circular, longitudinal, and diagonal muscles. The distribution of the muscle fibers in the body wall differed among the anterior, middle, and posterior body regions of the worm. The musculature of the attachment organs, the oral and ventral suckers, includes several types of muscles: the external equatorial and meridional muscles, internal circular and semicircular muscles, and radial muscles. Inside of the ventral sucker the diagonally located muscles were revealed and the supplementary u-shaped muscles were found adjoined to the base of the sucker from outside. The musculature of the internal organs composed of the excretory, reproductive, and digestive systems were characterized. Our results increase our knowledge of the morphology of trematodes and the arrangement of their muscle system.     

Synthesis of polymeric neoglycoconjugates based onN-substituted polyacrylamides

Several types of polymeric glycoconjugates,N-substituted polyacrylamides, have been synthesized by the reaction of activated polymers with -aminoalkylglycosides: (i) (carbohydrate-spacer) _n -polyacrylamide, pseudopolysaccharides; (ii) (carbohydrate-spacer) _n -phosphatidylethanolamine _m -polyacrylamide, neoglycolipids, derivatives of phosphatidylethanolamine; (iii) (carbohydrate-spacer) _n -biotin _m -polyacrylamide, biotinylated probes; (iv) (carbohydrate-spacer) _n -polyacrylamide-(macroporous glass), affinity sorbents based on macroporous glass, covalently coated with polyacrylamide. An almost quantitative yield in the conjugation reaction makes it possible to insert in the conjugate a predetermined quantity of the ligand(s).Pseudopolysaccharides proved to be a suitable form of antigen for activation of polystyrene and poly(vinyl chloride) plates (ELISA) and nitrocellulose membranes (dot blot), being advantageous over traditional neoglycoproteins. Polyvalent glycolipids insert well in biological membranes: their physical properties, particularly solubility, can be changed in a desired direction. Biotinylated derivatives were used as probes for detection and analysis of lectins.Abbreviations sp spacer arm - PAA polyacrylamide - PE phosphatidylethanolamine - Biot biotin - MPGlass macroporous glass 200 Å - ELISA enzyme-linked immunosorbent assay - HPLC high-performance liquid chromatography - AIBN azodiisobutyronitrile - BSA bovine serum albumin - DMG 3,6-di-O-methyl-d-glucose - TLC thin-layer chromatography - DMF dimethylformamide - DMSO dimethylsulfoxide - RI refractive index - PBS phosphate buffered saline (0.14m NaCl, 0.01m sodium phosphate, pH 7.3)     

Topography of rna in the ribosome localization of the 16 s rna 5' end by immune electron microscopy

The location of the 5′ end of 16 S RNA on the 30 S subunit has been determined. This has been done using immune electron microscopy of the 30 S subunits reconstituted from the 16 S RNA carrying 2,4-dinitrophenyl-hapten at its 5′-terminal phosphate group. Triphenylphosphine/2,2′-dipyridyl disulfide and 2,4-dinitrophenyl-ethylenediamine have been used as condensing and nucleophilic reagents, respectively, for modification of 16 S RNA. The reaction proceeds rapidly in mild conditions and results in a high yield of the modified RNA. Thus, a new general procedure for labeling the 5′-terminal nucleotides of high molecular weight RNAs is described. The 5′ end of 16 S RNA has been found to be located on a “lower” one-third of the small ribosomal subunit, on the side opposite to the ledge (platform).     

Stimulation of Burn Wound Healing in Rats by Nanosecond Repetitive Pulsed Microwave Radiation

Biology Bulletin - The effect of nanosecond repetitive pulsed microwave radiation (RPMR, 10 GHz, 100 ns pulse duration, 8 Hz pulse repetition rate, 140 and 1500 W/cm2 peak power flux density...