Systems-level analysis of host-pathogen interactions using mass spectrometry-based proteomics (Times New Roman, 12, bold) Xiaoyun Liu1, Beile Gao2, Jorge Galan2 1 Peking University, College of Chemistry, Beijing, 100871, China 2 Yale University, Department of Microbial Pathogenesis, New Haven, CT, 06519 Corresponding to: email@example.com Over the years characterization of individual virulence factors has been the mainstream in the field of bacterial pathogenesis. However, a deeper and overall understanding of host-pathogen interactions requires systems-level studies of dynamic microbial infection from an integrative perspective. Emerging high-throughput technologies such as mass spectrometry-based proteomics can be an ideal toolbox because it enables global quantitative measurements of protein constituents in an organism as well as their post-translational modifications. Here the state-of-the-art proteomic tools were utilized to examine the landscape of bacterial protein expression during infection with Campylobacter jejuni as a model. Proteome-wide analysis indicated that this bacterium undergoes a significant metabolic downshift including both aerobic and anaerobic respirations. Furthermore, our results suggested that intracellular C. jejuni favors anaerobic respiration using fumarate as the primary electron acceptors. These data are consistent with the observation that C. jejuni does not replicate within cultured mammalian cells and provide an explanation to its poor ability to grow under standard laboratory conditions when harvested from infected cells. (Times New Roman, 12) References: 1. Liu X, Valentine SJ, Plasencia MD, Trimpin S, Naylor S, Clemmer DE. J. Am. Soc. Mass Spectrom., 2007, 18(7), 1249-1264. Notes: 1. The presenter’s name should be underscored. 2. Please limit your abstract within one page. 3. The above applies to Chinese abstracts as well.