RFLP and Southern blotting analyses of HpaI- or EcoRV-digested DNA from pig GI disease isolates. Total DNA isolated from each of the specified C. perfringens strains was digested with HpaI (A) or EcoRV (B) and then Southern transferred. The Southern blots were probed with a 318-bp, DIG-labeled cpb2-specific probe. Results are shown for control strains CWC245 (a known cpb2-positive type C isolate) and 106527 (a cpb2-negative type C strain) and representative cpb2-positive pig GI disease isolates JGS1538, 120-98, 170-98, JGS1548, 97-4029, 2011, and JGS1818. The migration of the hybridizing band derived from each strain is indicated between the two blots.