FIG. 2.

(A) The resistance (+) or sensitivity (−) of strain 197N and the nine phage-resistant mutants to cell surface active agents was determined by the PE on medium containing each of the agents as described in the text. For the virulence scores, a plus indicates that that mutant showed no significant difference from the parent in terms of virulence (ID₅₀) and a minus indicates a statistically significant decrease in virulence (refer to Table 2 for additional information). (B) Silver-stained SDS-PAGE analysis of LPS solubilized from equivalent numbers of the parent (197N) and phage-resistant mutant cells. Complete (O-antigen-containing) LPS and incomplete LPS (O antigen absent) are denoted by the brackets.