Colon-Protecting Mucus Layer (image) University of Michigan Health System Share Print E-Mail Caption A thick mucus layer, generated by the cells of the colon's wall, provides protection against invading bacteria and other pathogens. This image of a mouse's colon shows the mucus (green) acting as a barrier for the "goblet" cells (blue) that produce it. In this case, the mice were raised in a germ-free environment, then received a transplanted set of human gut microbes. When the mice were fed a high-fiber diet, the mucus layer was thick and microbes that can digest fiber flourished. But on a fiber-free diet, the mucus layer became much thinner after microbes capable of digesting mucus became more dominant. This left the goblet cells open to infection by a pathogen. Credit University of Michigan Usage Restrictions Credit University of Michigan Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.