PCR analysis of the left and right junctions of
the VPI. (A) Similar sized fragments containing the left
junction for all strains with primers KAR94/KAR97. (B)
Similar sized fragments containing the right junction for all strains
with KAR23/KAR87. Lanes: 1, 6th pandemic strain 395; 2, 7th pandemic
strain N16961; 3, O139 Bengal strain AI1837; 4, U.S. Gulf coast strain
E506; 5, 1937 Sulawesi strain 66–2; 6, non-O1/non-O139 CT-positive
strain ATCC25872 from Czechoslovakia; 7, non-O1/non-O139 CT-positive
strain S-21 from Sudan; center lane, 1-kb marker.