Expression and purification of a new lectin from mussel Mytilus trossulus.

The gene of mtl from the mussel Mytilus trossulus was cloned into pET-40b(+) expression vector. After expression in E. coli using designed MX-medium an instable soluble form of MTL was obtained. The developed isolation method of the recombinant protein in "semi-denatured" conditions allowed obtaining an active soluble form of the homogenous lectin from the mussel M. trossulus (r-MTL). Both of the lectins had similar antigenic and spatial structures.

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.

Lectins of marine hydrobionts.

Data from the literature and results of our research on lectins isolated from some kinds of marine hydrobionts such as clams, ascidians, sea worms, sponges, and algae are presented in this review. Results of comparative analysis of the basic physicochemical properties and biological activity of lectins isolated from various sources are discussed.

[Carbohydrate-binding proteins of marine invertebrates].

The information on the carbohydrate specificity and molecular organization of some carbohydrate-binding proteins (lectins) of marine invertebrates is reported. Antiviral activity of some of the lectins against human immunodeficiency virus has been studied. Lectins of marine invertebrates are promising tools for studying natural glycoconjugates and cell effectors in vitro.

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.

Isolation and characterization of new GalNAc/Gal-specific lectin from the sea mussel Crenomytilus grayanus.

A lectin, Crenomytilus grayanus (CGL), was purified from sea mussel C. grayanus by affinity chromatography on acid-treated Sepharose 6B and following gel filtration on Sephacryl S-200. Molecular weight of the lectin obtained was determined by SDS-PAGE to be 18,000, independent of the presence or absence of beta-mercaptoethanol. CGL was found to agglutinate all types of the human erythrocytes together with mouse and rabbit. In hemagglutination inhibition assays, N-acetyl-D-galactosamine, D-galactose, and D-talose were the most potent inhibitors among the monosaccharides tested. Out of the oligosaccharides containing nonreducing terminal D-galactose, melibiose, and raffinose were found to be strong inhibitors. On the other hand, among the glycoproteins, asialo-BSM was the best inhibitor. The hemagglutinating activity of CGL was independent of the divalent cations Ca2+ and Mg2+. Significant CGL activity was observed between pH 8-10.

[Structure of the polysaccharide component of the bioglycan from the sea scallop Patinopecten uessoensis]. / Stroenie polisakharidnogo komponenta bioglikana morskogo grebeshka Patinopecten uessoensis.

A bioglycan, [alpha]20D + 144 degrees (c 0.7, water), was isolated from the mantle of the scallop Patinopecten yessoensis, which is widespread in the Sea of Japan. The bioglycan represents a complex of alpha-D-glucan (83%) and protein (13%) and was homogeneous as judged by gel-filtration and ultracentrifugation. By means of molecular-sieve chromatography on Sepharose CL-4B, its average molecular weight was estimated as 4 MDa. Methylation studies, periodate oxidation and amylolysis showed that the polysaccharide part of the bioglycan consisted of alpha-1,4-linked D-glucopyranose residues, with side chains attached to every fourth sugar unit of the backbone through alpha-1,6-linkages (some side chains seem to be 1,3-linked). The structure of the bioglycan was confirmed by NMR spectral data. Amino acid composition of the protein part of the bioglycan was elucidated. The scallop bioglycan is related to the known bioglycans-immunomodulators of marine invertebrates with regard to the structure and immunological behaviour.

The structure of mytilan, a bioglycan-immunomodulator isolated from the mussel Crenomytilus grayanus.

Mytilan, isolated from the mantle of the mussel Crenomytilus grayanus and which possesses high immunomodulating activity, is a non-covalently linked complex of a polysaccharide (95%) and protein (5%) with lectin activities. Chromatography of mytilan on agarose separated the polysaccharide and protein constituents. The protein appeared to have the lectin properties. Methylation analysis, Smith degradation, digestion with alpha-amylase, and 13C-n.m.r. spectroscopy showed the polysaccharide to be a glycogen-like alpha-D-glucan.

[Effect of mytilan--a polysaccharide from Crenomytilus grayanus--on local suppurative processes]. / Vliianie mitilana--polisakharida iz Crenomytilus grayanus na mestnyi gnoinyi protsess.

The study on the effect of mytilan on the local suppurative processes caused by administration of a virulent staphylococcal culture to the mouse pad showed that this polysaccharide isolated from Crenomytilus grayanus had a pronounced antiexudative and antinecrotic effect. The positive results of the experiments may be explained by stimulation of the phagocytic activity of polymorphonuclear leukocytes and macrophages by mytilan which results in acceleration of the reparative processes in local staphylococcal infection. Hence, nonspecific stimulation of the defense mechanisms in local suppurative infection by mytilan and its antiexudative and antinecrotic effect are promising for investigation of the possibility of the mytilan clinical use.

[Effect of polysaccharides isolated from marine invertebrates on various functions of T- and B lymphocytes]. / Vliianie polisakharidov, vydelennykh iz morskikh bespozvonochnykh, na nekotorye funktsii T- i B-limfotsitov.

The effect of bioglycans from sea invertebrate on the level of the rosette forming cells (RFC) in the spleen, development of the delayed type hypersensitivity (DTH) induced by sheep red blood cells (SRBC) and the levels of hemagglutinins and hemolysins in the blood serum was studied in experimental animals. It was shown that the polysaccharides administered parenterally in a single dose had an effect on the humoral and cellular immunity. Under the effect of these preparations the level of the RFC in the spleen of the mice increased, with the increase of the RFC belonging to the lymphocyte T2- and B-subpopulations being more intensive. The use of the polysaccharides increased the mean geometric titers of serum antibodies. The polysaccharides administered at different periods with respect to the immunization and antigen challenge either decreased or increased the DTH induced by SRBC.

[Action of bioglycans from marine invertebrates on macrophage functioning]. / Deistvie bioglikanov morskikh bespozvonochnykh na funktsional'nuiu aktivnost' makrofagov.

The data on the absorption and bactericidal function of macrophages are presented. It was shown in vivo that bioglycans 42 and 106 had a stimulating action on phagocytosis of Y. pseudotuberculosis and S. typhimurium capable of persisting in macrophages for prolonged periods. Addition of the bioglycans to the cultures of the macrophages from intact animals increased the absorption activity of the macrophages and somewhat potentiated their bactericidal activity. Under the action of the bioglycans the level and rate of the carbon clearance in the blood flow increased. The results of the study are promising for adequate control of infections caused by intracellularly located pathogens.