Electrophoretic variation of enzymes: a further marker for genetic studies of the Eimeria

Embryo-adapted strains of Eimeria mivati and E. mivati var. diminuta, differing in their sensitivity to sulphaquinoxaline and electrophoretic mobilities of lactate dehydrogenase, were crossed. E. mivati was sulphaquinoxaline-resistant and characterised by an electrophoretic form of the enzyme denoted lactate dehydrogenase-1 whereas E. mivati var. diminuta was sulphaquinoxaline-sensitive and characterised by lactate dehydrogenase-6. Progeny recovered from the cross were passaged in embryonating eggs given sulphaquinoxaline and the (drug-resistant) parasites recovered were characterised by both lactate dehydrogenase-1 and lactate dehydrogenase-6. Controls showed that those parasites characterised by the recombinant phenotype of drug-resistant and lactate dehydrogenase-6 had been produced by the cross-fertilisation of gametes.