Radioprotective Properties of Neomitilan in Experimental Radiation Pneumonia.

The efficiency of neomitilan, a polysaccharide isolated from Crenomytilus grayanus mussels, was studied in experimental model of radiation pneumonia (irradiation of the animal lungs with a total dose of 14 and 28 Gy). Histological study showed that an increase in the number of nucleated components in the lungs of animals subjected to neomitilan inhalation prior to irradiation. Proliferation of bronchial epitheliocytes and the formation of additional lymphoid structures were also revealed in these animals. The absence of a tendency to lung tissue recovery in animals irradiated with 28 Gy is due to extreme radiation toxicity.

Peculiarities of vasomotor reaction of cerebral vessels in arterial hypertension.

We studied vasomotor activity of rat cerebral vessels. Peculiarities of endothelium-dependent reactions of cerebral arteries in induced arterial hypertension were revealed. Quantitative and qualitative relationships between the parameters of the vasomotor apparatus of cerebral arteries and parameters of circulatory homeostasis were determined.

Noninvasive study of vasodilatory activity of albino rat cerebral arteries.

Vasodilating activity of rat cerebral vessels was studied. Methodological peculiarities and chronotropic limits of vasomotor testing were determined. Qualitative and quantitative parameters of dilatation of vessels were determined and similarity of rat dilatation responses and human vasodilatory activity was described.

Effect of lectin from the ascidian on the growth and the adhesion of HeLa cells.

Cell adhesion molecules, some of which are lectins, play a key role in the control of normal and pathological processes of various living organisms. We found herein that N-acetyl-D-glucosamine-specific lectin, isolated from the ascidian Didemnum ternatanum (DTL), alters the growth properties of HeLa tumor cells depending on the anchorage. DTL was shown to increase the proliferation of HeLa cells grown in soft agar greatly (in anchorage-independent fashion). In contrast, DTL inhibits the proliferative activity of HeLa cells grown on solid substrate and acts as inductor of differentiation, slowing cell growth, increasing the cell attachment and spreading. Scanning electron microscopic data have demonstrated that DTL treatment resulted in pronounced changes of the shape and surface of HeLa cells. Changes of cellular morphology correlated with essential redistribution of actin microfilaments.

Effect of ionic carbohydrate-containing biopolymers on complement activation.

We studied in vitro effects of charged polysaccharides on the classic and alternative pathways of complement activation. The complement system was affected by substances having different charges. Our findings suggest that the conformation of polysaccharide molecules, but not their charge, plays a primary role in the interaction with C1 and C3 complement components followed by initiation of cascade enzymatic reactions.

Inhibition of complement activation by water-soluble polysaccharides of some far-eastern brown seaweeds.

Fucoidans and laminarans from Laminaria cichorioides, Laminaria japonica, Fucus evanescens, laminaran from Laminaria gurjanovae, other beta-D-glucans (translam, pustulan and zymosan) and lambda-carrageenan from Chondrus armatus were used to study the effect of water-soluble polysaccharides from seaweeds on the alternative pathway of complement (APC). beta-D-Glucans and fucoidans under study differed appreciably from each other by structural characteristics, and also by degree of purification. beta-D-glucans, on ability to bind complement, ranked in a line according to a degree of their purification. Highly purified beta-D-glucans under study did not reveal an ability to bind complement. The fucoidans were divided conventionally into three groups according to their action on APC. Highly sulfated alpha-L-fucan from L. cichorioides with the greatest activity toward APC and caused 50% inhibition of reaction of activation (RA) of APC in a concentration of 0.5-0.7 mg/ml. Opposite 50% of inhibition of lysis of erythrocytes by sulfated heterogeneous fucoidan from L. japonica was achieved with 20 mg/ml. All other fucoidans and lambda-carrageenan have activity at 6-10 mg/ml concentration. Decreasing the sulfate content from 36% up to 9% in sample fucoidans under study was not reflected practically in the 50% inhibition concentration. Apparently, the degree of sulfating of fucoidans did not influence their action on APC. But the positive influence of fucose in structure of polysaccharide was obvious.

The membranotropic activity of cyclic acyldepsipeptides from bacterium Bacillus pumilus, associated with the marine sponge Ircinia sp.

The isolate of Bacillus pumilus associated with the marine sponge Ircinia sp. produced the surfactin-like lipopeptides, cyclic acyldepsipeptides. The hemolytic activity of individual cyclic acyldepsipeptides, bacircines (BI) 2, 3, 4, 5 and 5A having different acyl side chain structures (anteiso-C13, iso-C14, normal-C14, anteiso-C15, and iso-C15, respectively) was studied. The hemolytic power of bacircines depended on both the structure of the side chain (n->iso->anteiso-) and pH values (5.6 and 6.5 > 7.4). Hemolytic potency as a function of BI 5 concentration was given for pH 6.5; 7.4; 8.0; 9.0. pH dependent hemolysis induced by BI 5 was shown to be reversible. The membrane damaging potential of bacircine 5 (5 microM) at pH 6.5 was characterized by a higher rate of hemolysis and by a shorter time between the introduction of BI 5 solution into the RBC samples and the onset of hemolysis. Under this condition, BI 5 decreased abnormally the microviscosity of erythrocyte ghosts bilayer. The damaging potency of BI 5 decreased with an increase pH from 6.5 to 7.4 or its decrease from 6.5 to 4.9. It was shown that fatty acid bacircine fragment penetrated into the lipid bilayer to a depth of minimum 7 carbon atoms. Constants of dissociation of the Asp (pK 4.75) and Glu (pK 6.65) residues of bacircine in the lipid bilayer were obtained. These results showed that at pH 6.5 BI 5 possessed membranotropic activity in the monoionic form.

Adhesive and growth properties of lectin from the ascidian Didemnum ternatanum on cultivated marine invertebrate cells.

The effects of N-Acetyl-D-glucosamine-specific lectin (M(r) 27 kDa) isolated from the ascidian Didemnum ternatanum on cultivated cells of molluscs and echinoderms were studied. This lectin was found to stimulate the growth or the differentiation of cultivated marine invertebrate cells depending on the stage of embryonic development at which primary cell cultures were obtained. In addition, it has been shown to increase the attachment of cells in primary cultures of these animals. The degree of attachment is considerably increased when collagen or polylysine substrates are used. Using scanning electron microscopy we have demonstrated the stage-specific effect of this lectin on embryonic sea urchin and molluscan cells. Intensive cell spreading and an alteration of cell shape were observed only at the gastrula stage, when the switching from maternal information to embryonic genes occurred. The ascidian lectin seems to have some characteristics of both an adhesive factor and a growth factor.

New glycolipids (chitooligosaccharide derivatives) possessing immunostimulating and antitumor activities.

New glycolipids, derived from chitooligosaccharides of dp 2-4 and containing both free and acylated amino groups, were synthesized. The structure of the key compounds (di-, tri-, and tetra-saccharides acylated with different fatty acids) were elucidated by 13C NMR spectroscopy. Only the amino group of the reducing end of the chitooligosaccharides was found to be acylated when equimolecular amounts of reagents were used. The compounds obtained were shown to possess a low toxicity and certain immunostimulatory and antitumor activities. An induction of interleukin-1 and tumor necrosis factor by the immunocompetent cells and an augmentation by 140-180% of the mean life of mice with the Erlich carcinoma were observed.

D-3-Dodecanoyltetradecanoic acid as a constituent of lipid A from the lipopolysaccharide of Yersinia pseudotuberculosis.

D-3-Dodecanoyltetradecanoic acid has been separated from the lipid A of Yersinia pseudotuberculosis and its structure has been established by chromato-mass-spectrometry and 13C NMR spectroscopy, by comparison with authentic samples.