Paired IEF gels stained to show SOD activity as an achromatic zone without selective CuZnSOD inactivation (left) and in the presence of the CuZnSOD-inhibitor DEDC (right). Lanes contain whole-cell protein extracts from bacterial species, as follows: lane 1, Actinobacillus pleuropneumoniae (positive control) (5); lane 2, H. influenzae Eagan (negative control) (3); lanes 3 to 7, strains of the cryptic genospecies (strains 10N [lane 3], 12N [lane 4], 15N [lane 5], 11PS [lane 6], and 26E [lane 7]). The achromatic bands of activity corresponding to proteins with greater isoelectric points (lanes 1 and the approximate position indicated by an arrow for lanes 3 to 7), which are absent in the presence of DEDC, represents CuZnSOD. The zones unaffected by DEDC are not inhibited by 5 mM hydrogen peroxide (data not shown) and represent manganese-containing SODs.