Cryptochrom 4 (IMAGE) University of Oldenburg Caption The light-sensitive protein cryptochrome 4 (the yellow substance in the tube) is only stable for a short time. Photo: Christina Kuhaupt Credit University of Oldenburg Usage Restrictions Only to be used in connection with news story and appropriate 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.