figureposted on 13.04.2011, 00:00 by Andrew Weflen
My work focuses on the pathogenic interaction between Enteropathogenic E. coli (EPEC) and the intestinal epithelium, a single layer of cells reponsible for sealing our digestive tract and keeping bacteria, viruses and other particles from accessing the underlying tissue while regulating the absorption and secretion of water and various ions and nutrients. This image is a section of mouse small intestine, which was thinly sliced and mounted on slides, then stained using fluorescent probes for actin, a cytoskeletal protein, in green; occludin, a protein involved in sealing the spaces in between epithelial cells, in red; and DNA in blue. The tissue section was imaged using a wide-field epifluorescent microscope and 20x objective. The lower right corner of the image is the basal lamina, which is separated from the intestinal lumen, visible as the dark areas in the upper left corner, by epithelial cells, which are lined up one next to the other throughout the center of the image. What is striking about this image is that it is a stark illustration of the gravely important job that evolution has assigned to a single, 100-micron thick layer of cells.