Figure 9.

Influence of selective gene disruptions on G27 LPS response to cholesterol availability. In each experiment, parallel cultures of genetically altered G27 strains were grown overnight in defined medium without (-) or with (+) 50 μg/ml cholesterol. Cell lysates were adjusted to equal protein content, digested with proteinase K, and resolved on a 15% urea gel as described in Methods. Sample amounts loaded per lane correspond to 2 μg of cellular protein. Reference lanes contain 400 ng of purified LPS from E. coli strain O111:B4. A. LPS preparations from pairwise minus- and plus-cholesterol cultures of two individual cgt::cat G27 transformants. B. LPS from pairwise cultures of the O-chain-lacking pmi::cat G27 strain. C. LPS from pairwise cultures of wild type G27, or of isogenic lpxE::cat or eptA::cat strains.