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 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; 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.