Gut bacteria (IMAGE) University of California - Riverside Caption Illustration of bacteria in the human gut. Credit Darryl Leja, National Human Genome Research Institute, National Institutes of Health Usage Restrictions No restrictions. License Public Domain 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.