Haemagglutination activity of lectins from extracts of some Vietnam marine sponges

Aqueous extracts from 16 species of Vietnam marine sponges were examined for haemagglutination activity using native and enzyme-treated different animal and human erythrocytes. Among these, extracts from 14 species were found to have haemagglutinination activities toward at least one type of erythrocyte tested meaning that 87.5% of the surveyed marine sponge species possess haemagglutination activity. Strong activity was detected in extracts from marine sponge species Acanthella cavernosa, Axinyssa sp., Cinachyrella sp., 01NT.2.4, 3.5, 3.10, 3.11 and 3.18 with enzyme-treated various animal and human erythrocytes. In a haemagglutination–inhibition test with various monosaccharides and glycoproteins, haemagglutination activity of the extract from A. cavernosa had no affinity for any of the monosaccharides, but inhibited by porcine stomach mucin and fetuin, whereas activities of the extract from Cinachyrella sp. were strongly inhibited by monosaccharides, such as D-galactose and N-acetyl-D-galatosamine, but not with glycoproteins. The activity of Stylissa flexibilis extract was inhibited by D-galactose, porcine stomach mucin, fetuin and their asialo derivatives, suggesting the presence of lectin specific for O-glycans of this species. The activities of four sponge extracts from A. cavernosa, S. flexibilis, Axinyssa sp. and Cinachyrella sp. were stable over a wide range of pH and temperature. Haemagglutination activities of A. cavernosa, Axinyssa sp. and Cinachyrella sp. extracts were independent of the presence of divalent cations, except for the haemagglutination activity of extract from S. flexibilis, which was dependent on the presence of divalent cations. The results suggest that Vietnam marine sponges may be good sources of useful lectins for biochemical and biomedical applications.

Characterization of Lectin from Colpomenia Sinuosa and Effect of Physico Chemical Parameters on Haemagglutination Activity

Lectin is a protein which has the ability to bind carbohydrates and named as haemagglutinin. Lectins with specific carbohydrate specificity have been purified from various plant tissues and other organisms and exploited extensively in many aspects of biochemistry and biomedicine. Similar to land plants, lectins from marine algae appear to be useful in some biological applications. Although several studies on lectins from marine algae have been reported till date, few lectins from algae have been characterized in detail. The present study was focused on the lectin isolated from C.sinuosa. The algal lectin has high sugar specificity with N-acetylglucosamine and higher enzyme activity with trypsin. This lectin was identified as CaCl2 dependent – ‘C’ type lectin and was sensitive to EDTA. Higher H.A titre value was observed with CaCl2 and the lower with MnCl2 and ZnCl2 . Significant lectin activity was observed between pH 7 to 8 and temperature between 20 to 40 O C

HAEMAGGLUTINATION ACTIVITY OF THE EXTRACTS FROM SOME VIETNAM MARINE INVERTEBRATES

Aqueous extracts from 21 species of Vietnam marine invertebrates, including 11 bivalve and 10 gastropod species, were examined for haemagglutination activity using native and enzyme-treated different animal and human erythrocytes. The 8 bivalve and 10 gastropod species were found to have haemagglutinination activities toward at least one type of erythrocyte tested. A total of 86% of marine invertebrate species surveyed were active. Strong activity was detected in extracts from two bivalve species (Tridacna squamosa and Geloina coaxans) and three gastropod species (Tutufa rubeta, Pleuroploca trapezium and Tectus conus) with enzyme-treated rabbit, horse and human A, B, O erythrocytes. In a haemagglutination–inhibition test with various monosaccharides and glycoproteins, haemagglutination activities of two extracts from T. rubeta and P. trapezium had no affinity for any of the monosaccharides and glycoproteins tested, while activities of the extracts from T. squamosa and T. conus were strongly inhibited by porcine stomach mucin tested, suggesting the presence of lectins specific for O-glycans of these species. The activities of four marine invertebrate extracts were stable over a wide range ofpH and temperature. The haemagglutination activities of T. rubeta and P. trapezium extracts were independent of the presence of divalent cations, whereas the haemagglutination activity of extracts from T. squamosa and T. conus were slightly dependent on the presence of divalent cations. The results suggest that Vietnam marine invertebrates may be good sources of useful lectins for biochemical and biomedical applications.

Four molecules of the 33 kDa haemagglutinin component of the Clostridium botulinum serotype C and D toxin complexes are required to aggregate erythrocytes

Normally, large-sized botulinum toxin complexes (L-TC) of serotype C and D are composed of a single neurotoxin, a single non-toxic non-haemagglutinin, two HA-70 molecules, four HA-33 molecules and four HA-17 molecules that assemble to form a 650 kDa L-TC. The 540 and 610 kDa TC species (designated here as L-TC2 and L-TC3, respectively) were purified in addition to the 650 kDa L-TC from the culture supernatants of serotype D strains (D-4947 and D-CB16) and serotype C strains (C-6814 and C-Yoichi). The 650 kDa L-TC from D-4947, D-CB16 and C-6814 showed haemagglutination and erythrocyte-binding activity, but their L-TC2 and L-TC3 species had only binding activity. In contrast, every TC species from C-Yoichi having the C-terminally truncated variant of HA-33 exhibited neither haemagglutination activity nor erythrocyte-binding activity. Four strain-specific HA-33/HA-17 complexes were isolated from the 650 kDa L-TC of each strain. The 650 kDa HA-hybrid L-TCs were reconstituted by various combinations of isolated HA-33/HA-17 complexes and haemagglutination-negative L-TC2 or L-TC3 from each strain. HA-hybrid 650 kDa L-TC, including at least one HA-33/HA-17 complex derived from C-Yoichi, lost haemagglutination activity, leading to the conclusion that the binding of four HA-33 molecules is required for haemagglutination activity of botulinum L-TC. The results of the modelling approach indicated that the structure of a variant C-Yoichi HA-33 molecule reveals clear deformation of the β-trefoil domain responsible for the carbohydrate recognition site.