This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
The pathogenecity of Entamoeba histolytica is indicated by ? 
Select and explain. 
A. Isoenzyme pattern, B. Size, C. Nuclear pattern, D. ELISA test
A: Isoenzyme pattern
Answer: A: Isoenzyme pattern 
Explanation: Ans. is 'a' i.e., Isoenzyme pattern Zymodene There are distinct invasive and noninvasive strains of E. histolytica. These strains vary according to their isoenzyme patterns (zymodemes). E. histolytica strains have 22 zymodemes of these 10 zymodemes are invasive and 12 are noninvasive. Zymodemes of E. histolytica are identified according to the electrophoretic mobility of 4 enzymes. L-malate : NADP+ Oxidoreductase Phosphoglucomutase (PGM)-------- most impoant Glucose-phosphate isomerase Hexokinase Electrophoresis of PGM can show one or more of the 4 bands : a, 13, y and 5. Strains of E. histolytica showing, an absence of a-band together with the presence of 13 band are virulent i.e., invasive.