The image shows a mouse colon section depicting epithelial cell nuclei in blue (DAPI stain) as well as mucus in yellow (UEA-1, a lectin stain) and green (a MUC-2 antibody). Image by Carolina Tropini, University of British Columbia (Canada) and Justin Sonnenburg, Stanford University (USA); image modified by MIC. The cover is published under the Creative Commons Attribution (CC BY) license.