Isoenzyme activities of different strains of Cryptosporidium parvum

Different isoenzyme activities have been assayed in three strains of Cryptosporidium parvum, C1 (C. parvum from infected calves, UK), C2 (C. parvum from infected calves, Egypt) and C3 (C. parvum from infected goats, Egypt). The electrophoretic variations of five enzymes; lactate dehydrogenase (LDH), glucose phosphate isomerase (GPI), hexokinase (HK), malate dehydrogenase (MDH) and glutamate dehydrogenase (GLDH) were compared among the three different isolates using native polyacrylamide gel-electrophoresis. LDH showed an identical pattern in the three isolates. GPI showed two different bands in C3 and C1, with both bands present in C2. HK activity showed a weak band in C1 but no reaction was detected with C2 and C3. Malate dehydrogenase (MDH) showed no reaction in C1, but similar bands in C2 and C3. Glutamate dehydrogenase (GLDH) showed two different patterns, C2 and C3 had one pattern and C1 showed additional zones of reaction. Rat liver homogenate was run at the same time as the parasite extracts as a positive control. This investigation suggests that GPI, HK and GLDH could be used to characterise different Cryptosporidium isolates.