Myotubes (IMAGE) University of California - Berkeley Caption Mature muscle fibers were marked to glow green. Credit Image by Preeti Paliwal, UC Berkeley Usage Restrictions Non-commercial use allowed with image credit. 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.