So-called prenyltransferases are involved in the biosynthesis of hyperforin, which are made visible by coupling to yellow fluorescent protein. The enzymes are located in the envelope of chloroplasts, which appear red rather than green under the conditions chosen here. Picture credit: Eline Biedermann, David Kaufholdt/TU Braunschweig, Germany.

This image is part of: Picture of the Month: From the Plant to the Microorganism. Please note the copyright of this image.