by contrast , incubation with the fluorophore , 7-nitro-4-chlorobenz-2-oxa-1,3-diazole ( nbd-cl ) confers fluorescence only on actin , without impairing contractility , but the polarization of such fluorescence changes in a different direction and magnitude from myosin-originating fluorescence .
C0001271
actin
C0026820
contractility