Ulcer-Causing Bacteria (IMAGE) U.S. National Science Foundation Caption Contact with stomach acid keeps the mucin lining the epithelial cell layer in a gel-like state. Credit Zina Deretsky, National Science Foundation Usage Restrictions None License Licensed content 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.