(IMAGE) Center for Genomic Regulation Caption Live cell imaging of human follicle, showing granulosa cells on the outer layer, which support the oocyte, contained within. The activity of reactive oxygen species is shown in red. The researchers observed ROS activity in the granulosa cells but it is virtually absent in the oocyte. Credit Aida Rodriguez/Nature Usage Restrictions Credit must be given to the creator. License CC BY 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.