Demonstration of detachment of mNYD-SP27 from mouse sperm. Demonstration of the detachment of mNYD-SP27 from mouse sperm during the capacitation and the acrosome reaction by chlortetracycline (CTC) and mNYD-SP27 immunofluorescence double staining. CTC staining was used to show the different conditions of the sperm, from uncapacitated to capacitated to acrosome-reacted (a to f). The amount of mNYD-SP27 in sperm was determined by immunofluorescence using a secondary antibody labelled with tetraethyl rhodamine isothiocyanate (TRITC). CTC and mNYD-SP27 merged micrographs were used to show the change of mNYD-SP27 in sperm at different stages. The bright field micrographs were taken through differential interference contrast and show the morphology of the sperm. The merged images show that the amount of mNYD-SP27 in sperm decreased as the sperm underwent capacitation and the acrosome reaction, and almost disappeared after the acrosome reaction. DIC, differential interference contrast.