Aliquots taken after digest only or after the extraction/precipitation procedure were resolved on a 15% urea gel. Each lane represents an amount of AZD0156 Sample material derived from an equivalent amount of the initial cell lysate (2 μg protein). The reference lane contains 400 ng of LPS from E. coli O111:B4 as a silver staining control. No bands were selectively gained or lost in the workup

following proteolytic digestion. Figure 8 LPS structure in H. pylori strain G27 responds specifically to growth in cholesterol. In two independent experiments, parallel cultures of H. pylori strain G27 were Baf-A1 mw grown overnight in defined medium. The growth media contained the following, each at 130 μM: lanes 1, 2, 5, no addition; lanes 3, 6, cholesterol; MM-102 lane 4, synthetic β-sitosterol; lane 7, taurocholate; lane 8, glycocholate. At the end of the growth period the cultures were chilled on ice, and an equivalent amount of cholesterol was then added to sample 1. 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 3 μg of cellular protein (lanes 1-4), or 2 μg (lanes 5-8). The indicated reference lane contains 400 ng of purified LPS from E. coli strain O111:B4. Arrows mark the specific bands that diminish in cholesterol-grown cultures.

The same LPS response to growth in cholesterol occurred in transformed G27 strains in which the cholesterol α-glucosyltransferase gene had been disrupted (Figure 9A). Therefore, α-glycoside metabolites of cholesterol were not required for the LPS changes observed on silver-stained gels. 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 Thiamet G 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. We also investigated cholesterol responsiveness of LPS in a G27 pmi::cat strain lacking O-antigen chains (Figure 9B). As in wild type G27, this strain showed the presence of an additional, more slowly-migrating band in the core region that was diminished or lost upon growth in cholesterol.