Fig. 6. Myofibrils from wild-type Drosophila muscles incubated in contraction buffer for 20 min and simultaneously stained using anti-glycerol-3-phosphate dehydrogenase (GPDH) and phalloidin. Note the correspondence of the brightly fluorescent GPDH signal with the very faint, narrow dark bands on the phalloidin-stained myofibril.