Beta-tubulin and benzimidazole resistance in the sheep nematode Haemonchus contortus.
We have compared benzimidazole (BZ) susceptible (s) and resistant (R) strains of Haemonchus contortus from sheep by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), Western blotting and ELISA techniques. The S strain bound more drug per mg protein than the R strain. BZ binding could be resolved into high-affinity and low-affinity binding. Low-affinity binding in parasite preparations devoid of tubulin was observed, but high-affinity binding occurred only in preparations containing tubulin. Resistance was associated with a decrease in the high affinity component. The S and R strains were shown by ELISA to contain similar total amounts of tubulin. By 2-D PAGE, the beta-tubulin isoform pattern of the S strain was different from that of the R strain, but the alpha-tubulin isoform patterns of the 2 strains were similar. BZ resistance was associated with a decrease in high-affinity BZ binding to tubulin and an alteration in beta-tubulin isoform pattern.
Lubega
G W
GW
Institute of Parasitology, McGill University, Sainte Anne de Bellevue, Quebec, Canada.
Prichard
R K
RK
D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism / Q000494:pharmacology*; D002846:Chromatography, Affinity; D004351:Drug Resistance; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006189:Haemonchus / Q000187:drug effects* / Q000378:metabolism; D010063:Ovum / Q000378:metabolism / Q000469:parasitology; D011107:Polylysine; D011955:Receptors, Drug / Q000032:analysis; D012756:Sheep / Q000469:parasitology*; D014404:Tubulin / Q000378:metabolism / Q000494:pharmacology*
D001562:Benzimidazoles; D011955:Receptors, Drug; D014404:Tubulin; D011107:Polylysine