ISOELECTRIC-FOCUSING OF SOLUBLE-PROTEINS IN THE CHARACTERIZATION OF SPECIES AND ISOLATES OF NEMATODIRUS (NEMATODA, TRICHOSTRONGYLOIDEA)

Isoelectric focusing was performed on extracts from Nematodirus spathi ger, Nematodirus filicollis, Nematodirus helvetianus, and 3 geographic isolates of Nematodirus battus. Gender-specific differences were note d within species; however, the overall protein profile of each species and isolate was distinct and reproducible and allowed unequivocal dif ferentiation. A coefficient of similarity (Sm) for males of each speci es and isolate was calculated, and a dendrogram, based on evaluation o f Sm by the unweighted pair-group method with arithmetic means, was pr oduced. Although cluster analysis of the 3 isolates of N. battus indic ates the North American and Weybridge isolates are similar, interpreta tion of the relationships and thus the history of introduction based o n these data is equivocal. Isoelectric focusing is a robust method for establishing identity and has great utility in diagnostics. However, in the absence of selective histochemical staining, interpretation of identity and homology for specific bands and banding patterns is probl ematic, thus limiting the utility of this method for phylogenetic infe rence.