Fluorescence of adult B. floridana and of heterologously expressed LanFP1 and LanFP2. (A) Brightfield images of the oral cavity of adult Branchiostoma floridae are overlayed onto fluorescence images. The green and red fluorescence was separated using linear unmixing of the two most distinct fluorescence spectra. (B) The composite image of the entire oral cavity created by merging images obtained using either GFP or Texas Red filter. (C) Limited overlap between the green and red emitted fluorescence in the L-shaped rod connecting the oral cirri to the skeletal muscle (a higher-resolution fragment of panel C). (D) HEK-293 cells transiently expressing LanFP1. (E) The emission spectra from the adult Branchiostoma floridae. (F) Comparison of the green spectrum from panel E with the emission spectra of LanFP1 and LanFP2s expressed in HEK-293 cells.