Mallet_1997_Vet.Res_28_287

Acetylcholinesterase (AChE) secreted by seven different ruminant trichostrongyles was studied in vitro. AChE activity was particularly high (84 and 160 x 10(-3) M.g-1.min-1) in the excretion products of Nematodirus spathiger and N battus, moderate (3 and 5 x 10(-3) M.g-1.min-1) for Trichostrongylus colubriformis and T vitrinus and low (0.9 x 10(-3) M.g-1.min-1) for Teladorsagia circumcincta. No activity was observed with Haemonchus contortus and Cooperia curticei. At 4 degrees C, 80% of AChE activity was maintained over 72 h except for T circumcincta where a loss of 50% was observed after 24 h. At 37 degrees C, N spathiger and T colubriformis maintained an activity over 72 h, but for the other species, a loss of 50% was observed after 24 h. The molecular weights of the AChE from the different species, estimated by gel filtration (Sephadex S300HR), ranged between 64 and 150 kDa. The coefficients of sedimentation estimated by sucrose density gradient ranged between 4.8 S and 7.8 S and corresponded to a monomeric hydrophilic form (G1). For T vitrinus, an amphiphilic form was suspected.