Lectins are cell-agglutinating proteins or glycoproteins of non-immune origin that bind carbohydrates without modifying them chemically. These molecules occur greatly in plants and to some extent also in invertebrates in which spiders are rarely explored. The spider genus Lasiodora is widely distributed in Brasil and has been taxonomically revised. This work aimed to detect and characterize lectin hemagglutinanting activity (HA) in the hemolymph of Lasiodora sp. Hemolymph sample was obtained by cardiac puncture, using apirogenic syringe and 3% NaCl supplemented with 2 mM propranolol to prevent the lysis of amebocyte and coagulation. The sample was centrifuged at 800g for 15 min at 4ºC to separate hemocytes and HA was assayed using human and rabbit erythrocytes. Lectin carbohydrate specificity assays were carried out using D (+) glucose, D (+) mannose, D (+) galactose, D (+) frutose and D (+) fucose (1.56 to 200 mM). The effects of pH and temperature on HA were evaluated in 0.1M Tris-HCl/0.15 M NaCl (pH 7.0, 7.5, 8.0, 8.5 and 9.5.) and under heating (30, 40, 50, 60 and 70ºC), respectively. Tests for bivalent cation requirement on HA were made using 0.15 M NaCl containing 10 mM Ca²⁺, Ba²⁺, Zn²⁺, Mg²⁺ e Mn²⁺. The lectin did not show specificity for none of the sugars tested; meanwhile it was observed a small inhibition of HA with 100 mM of galactose and fucose. HA decreased in pH 8.0 to 9.5 and it was abolished at 50 and 60°C when human type A and rabbit eryhrocytes were used, respectively. Bivalent cations did not affect the HA. Chromatography assays using gum guar (guaran) and DEAE-Sephadex are under investigation for purification purposes. The results demonstrated the presence of lectin(s) with different characteristics in the hemolymph of Lasiodora sp. The isolation of lectins will contribute for the characterization of this species still little known.
Supported by: CNPq/PIBIC