An improved method for the separation of lichen symbionts

A novel method for the isolation of lichen photobionts by density gradient centrifugation has been assessed using the lichen Evernia prunastri as an e xperimental model. An initial sucrose-KI gradient was prepared in which alg ae and small hyphal fragments formed an interphase in a sucrose-KI gradient . Then, 10 mM phosphate buffer is added and the preparation centrifuged a s econd time. This partitioned the algal cells towards the buffer while the b ulk of the fungal hyphae were retained in the sucrose solution. This method allowed the purification of algal cells with no contamination from the fun gal partner.