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.

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.

[Hemostasis and trophoblast-specific beta 1-glycoprotein in spontaneous abortion]. / Sistema gemostaza i trofoblasticheskii beta 1-glikoprotein pri nevynashivanii beremennosti.

The relationship between the increase in maternal serum concentration of pregnancy-specific beta 1-glycoprotein (SP1) and levels of components of hemostasis system was investigated. The concentrations of SP1 were measured in the blood sera of 234 pregnant women with recurrent spontaneous abortions, in 115 somatically healthy pregnant women and 75 donors. A direct correlation between serum SP1 and levels of components of hemostasis system was shown. Results suggest that disturbances in hemostasis system influence synthesis of some placental proteins, including SP1.

Trophoblastic beta1-glycoprotein and hemostasis system in pregnant women with antiphospholipid syndrome.

Clinical and laboratory studies were carried out in 38 pregnant women with antiphospholipid syndrome. Increased functional activity of platelets and decreased protein-producing function of the placenta were observed starting from the early terms of gestation. These disorders were followed by the development of hypercoagulation in the plasma component of hemostasis, appearance of intravascular blood clotting markers, and inhibition of AT III and protein C. This led to the progress of disorders in the microcirculatory bed, fetoplacental insufficiency, decrease in trophoblastic beta1-glycoprotein level, chronic hypoxia, and fetal death. Infection accelerated this process. Measurements of trophoblastic beta1-glycoprotein every 2 weeks help to diagnose fetoplacental disorders, predict the course of pregnancy, and evaluate the efficiency of drug therapy.

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.

[Conformational state of oncoprecipitin cyprein and its immunologic activity]. / Konformatsionnoe sostoianie onkopretsipitina tsipreina i ego immunologicheskaia aktivnost'.

The effect of solution ionic strength, calcium ion concentration, and temperature on spatial structure of cyprein was examined by CD, UV, and fluorescence spectroscopy. The secondary structure of the cyprein molecule was calculated from CD spectra, and the prevalence of the beta-structure (85%) was shown. An irreversible conformational transition in the range 55-60 degrees C was found, which reduces the binding activity of cyprein in interaction with carcinoembryonic antigen (CEA) and anti-cyprein antibodies. In the latter case, the binding activity was reversibly restored. Cyprein was shown to be a calcium-binding protein. Binding of calcium by cyprein and increasing the ionic strength of solution affect only tertiary structure of the protein. At an ionic strength of solution close to physiological conditions, calcium-bound cyprein shows maximum binding to CEA and anti-cyprein antibodies. It was shown by difference UV spectroscopy that cyprein does not interact specifically with the monosaccharides of the carbohydrate chains of CEA: fucose, mannose, galactose, and N-acetylglucosamine.

[Physico-chemical and immunochemical characteristics of molecular forms of carcinoembryonic antigen (CEA) not bound with concanavalin A]. / Fiziko-khimicheskaia i immunokhimicheskaia kharakteristika molekuliarnoi formy rakovo-émbrional'nogo antigena (REA), ne sviazyvaiushcheisia s konkanavalinom A.

A molecular form of CEA non-binding Con A (CEAnC) was isolated from colon adenocarcinoma metastases in liver as a fraction of CEA having no affinity to Con-A-Sepharose. CEAnC was shown to be immunochemically identical to CEA, but to differ substantially with regard to the amino acid and sugar composition, and structure of the sugar moiety, possibly containing non only N-, but also O-glycosyl carbohydrate chains. The antigens studied were also found to possess different spatial structures. The differences between CEA and CEAnC suggest CEAnC to be a new molecular form of CEA.

Carcinoembryonic antigen, its spatial structure and localization of antigenic determinants.

The effects of temperature and pH on the spatial structure of carcinoembryonic antigen (CEA) and its various derivatives are studied by circular dichroic spectroscopy and differential UV spectroscopy. The spatial organization of the protein portion of CEA and its derivatives as revealed by spectroscopic evidence is discussed with respect to the antigenic activity of the species studied. We conclude that the protein portion of CEA consists mainly of a beta-structural type. Using the various modifications of the sugar moiety and the protein portion, antigenic determinants of CEA are shown to possess the main conformational character of the molecule while participation of the sugars in the formation and orientation of the carbohydrate chains relative to the protein core of the antigen appear to be important.

[Physico-chemical and immunochemical characteristics of oncoprecipitins of crustacin and cyprein specifically reacting with carcinoembryonic antigen]. / Fiziko-khimicheskaia i immunokhimicheskaia kharakteristika onkopretsipitinov krustatsina i tsipreina, spetsificheski reagiruiushchikh s rakovoémbrional'nym antigenom.

Crustacin from Pagurus prideauxii and cyprein from Cyprea caputserpentis have been shown to be glycoproteins with molecular masses 36 +/- 1 and 44 +/- 1.4 kDa, containing 3 and 18% of carbohydrates, respectively. Their amino acid and monosaccharide composition have been determined. Crustacin or cyprein interact with CEA more specifically than carbohydrate-containing polymers with lectins. Carbohydrates unspecifically inhibit this interaction at rather high concentrations. Association constants of CEA-crustacin and CEA-cyprein complexes are 0.6.10(8) M-1, respectively. Besides, ELISA showed that antibodies against CEA bind antibodies to crustacin and cyprein.

[Localization of the antigenic determinants in carcinoembryonic antigen: the role of the carbohydrate component]. / Lokalizatsiia antigennykh determinant v rakovo-émbrional'nom antigene, rol' uglevodnogo komponenta.

The majority of topographic antigenic determinants of the carcinoembryonic antigen (CEA) representing a glycoprotein were shown to contain sugar residues of the CEA carbohydrate chains. Periodate oxidation of CEA followed by reduction afforded a corresponding CEA derivate (CEA-POR), which retained 3% antigenic activity of CEA. In secondary and tertiary structures CEA-POR was proved to be close to CEA pre heated to 80 degrees C. Formation of borate complexes with sugar residues of CEA decreased the CEA antigenic activity to 5% while a but did not affect the spatial structure of its protein core.