Differentiation of Sarcocystis species in European sheep by isoelectric focusing.

Isoelectric focusing was carried out on total proteins derived from cystozoites of Sarcocystis tenella, S. arieticanis and S. gigantea. The overall protein profile of each species was distinct and reproducible and enabled the unequivocal differentiation of the three Sarcocystis species. In total, approximately 60 bands could be counted for S. tenella and S. arieticanis and approximately 45 bands for S. gigantea cystozoites in the pH range of 3-9. Isoelectric points (pIs) were determined for dominant peaks of densitometric scans of gels in the pH range of 3-9 (cathodal and anodal sample application) and arbitrary identification numbers were assigned to 25 (5 and 20) peaks of S. tenella, 25 (8 and 17) peaks of S. arieticanis and 21 (7 and 14) peaks of S. gigantea; similar assignments were also used for 11 peaks of S. tenella, 18 peaks of S. arieticanis and 12 peaks of S. gigantea observed on densitometric scans of gels in the pH range of 4-6.5.