Rat Heart Muscle Tissue

The sample of rat heart tissue presented in the digital image above was labeled with Tetramethylrhodamine conjugated to wheat germ agglutinin, a lectin that selectively binds to N-acetylglucosamine and sialic acid residues, and with Alexa Fluor 488 conjugated to phalloidin, a phallotoxin that binds filamentous actin. The specimen was counterstained for nuclear DNA with 4',6-diamidino-2-phenylindole (DAPI). Images were recorded in grayscale with a 12-bit digital camera coupled to either a Nikon E-600 or Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.