Visualization of Amino Acid Metabolites in Intestinal Tissues of Infected Mice

Source: Specker, J. T., et al. Investigation of Microbial Cooperation via Imaging Mass Spectrometry Analysis of Bacterial Colonies Grown on Agar and in Tissue During Infection. J. Vis. Exp. (2022)This video demonstrates the use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to visualize amino acid distribution in intestinal tissues from mice infected with Clostridioides difficile, alone or in combination with Enterococcus faecalis. The procedure involves tissue preparation, matrix application, laser ionization, and detection of amino acid ions to generate spatial ion images. The results reveal microbial cooperation, as E. faecalis alters the gut environment by releasing ornithine and depleting arginine, thereby enhancing C. difficile pathogenesis.