Localization of actin in the sperm head of the plains mouse, Pseudomys australis.

Actin was localized in the sperm head of the plains mouse, Pseudomys australis, using NBD-phallacidin, a fluorescent-labeled phallotoxin. It was found to be present in the two ventral hooks in sperm from the testis, epididymis, and vas deferens. Faint fluorescence was observed in other regions of the sperm head, whereas autofluorescence occurred in the midpiece of the tail in some preparations. The material in the ventral hooks was also found to be birefringent, which is consistent with it showing preferential orientation.