Movie 1

Motility of wild-type spermatozoa. Spermatozoa were isolated from cauda epididymis of adult testis (19 weeks old) in HTF medium containing 0.5% methyl cellulose to increase viscosity and slow down sperm cells. Flagella beat vigorously and efficiently propel wild-type sperm cells. A cytoplasmic droplet, involved in the final removal of excess cytoplasm, is visible in the distal midpiece of some spermatozoa.