Variant proteins associated with ionophore resistance in sporozoites of Eimeria tenella (Coccidia).

Protein samples prepared from sporozoites of two ionophore-sensitive strains (WIS and Penn St) and three resistant strains (FS139, FS459, and FS462) of Eimeria tenella were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), native polyacrylamide gel electrophoresis (native PAGE), or two-dimensional electrophoresis with native PAGE and SDS-PAGE. Variant proteins that might be associated with ionophore resistance were observed in resistant field strains on native PAGE. When two-dimensional electrophoresis was conducted, four over-expressed peptides with approximate molecular weights of 97, 71, 70, and 50 kDa were observed in the FS139 field strain in comparison with the WIS laboratory strain.