Stained skeletal muscle tissue (IMAGE) Purdue University Caption Purdue University’s James Markworth, assistant professor of animal sciences, and PhD student Xinyue Lu observe results of immunofluorescent staining of a cross-sectional sample of skeletal muscle tissue stained with a cocktail of primary antibodies for muscle fiber type analysis. Muscle cells (myofibers) of differing contractile type, such as fast vs. slow twitch fibers, are distinguished via their resulting staining color. Credit Purdue Agricultural Communications/Joshua Clark Usage Restrictions News organizations may use this image in reports about the work of Purdue University's James Markworth and his collaborators. License Original 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.