Cholinesterase and phosphatase activities in adults and infective-stage larvae of levamisole-resistant and levamisole-susceptible isolates of Haemonchus contortus.
Cholinesterase (ChE) and acid phosphatase (AP) activities, but not alkaline phosphatase activities, were detected in cytosolic and membrane-bound fractions of adult and infective-stage larvae of levamisole-resistant and levamisole-susceptible Haemonchus contortus. In contrast to other gastrointestinal nematodes, the ChE activity was higher in L3 than in adults and, in both cases, was mainly associated with membranes. ChE activity was inhibited by Triton X-100 and was only detected in membrane-bound fractions when the detergent was removed. Differences between resistant and susceptible L3 were observed in the response to inhibitors (cytosolic fraction) and in the enzymatic content (membrane-bound fraction). Phosphatase activity was detected at acidic pH in all fractions, being higher in the adult than in the L3 stage. In the former, most of the enzyme was localized in the membrane-bound fractions, whereas in the latter it was mainly in cytosolic fractions. This difference could be correlated with the activity in the gut. In inhibition assays, a difference between cytosolic fractions from resistant and susceptible adults was observed in their response to 1 mmol/L tartaric acid.
Giménez-Pardo
C
C
Laboratory of Parasitology, Faculty of Pharmacy, Department of Microbiology and Parasitology, Alcalá University, Crtra. Madrid-Barcelona Km. 33 28871, Alcalá de Henares, Madrid, Spain. consuelo.gimenez@uah.es
Martínez-Grueiro
M M
MM
Gómez-Barrio
A
A
Rodríguez-Caabeiro
F
F
D000135:Acid Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology*; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D002802:Cholinesterases / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D004351:Drug Resistance; D006189:Haemonchus / Q000201:enzymology* / Q000254:growth & development; D007814:Larva / Q000201:enzymology; D007978:Levamisole / Q000494:pharmacology*; D017830:Octoxynol / Q000494:pharmacology; D013770:Tetraisopropylpyrophosphamide / Q000494:pharmacology
D000871:Anthelmintics; D002800:Cholinesterase Inhibitors; D007978:Levamisole; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide; D013770:Tetraisopropylpyrophosphamide; D017830:Octoxynol; D002802:Cholinesterases; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase