FIG. 5.

Validation of the plasma membrane probe FM4-64 as an AR indicator and its simultaneous observation with the calcium indicator Fluo-4 AM. A) Representative fluorescence images of the time course of an FM4-64-labeled EGFP-sperm that does not undergo AR after addition of 10 μM ionomycin (IONO). B) EGFP and FM4-64 fluorescence intensities (in arbitrary units) of the sperm shown in A. C) Representative fluorescence images of the time course of FM4-64-labeled EGFP-sperm undergoing AR after addition of 10 μM ionomycin. D) EGFP and FM4-64 fluorescence intensities (in arbitrary units) of the sperm shown in C. E) Fluorescence images of FM4-64- and Fluo-4 AM-labeled sperm.