Chapter 12 Cell Biology of Nematode Sperm

This chapter reviews methods that have been developed for working with the amoeboid sperm of nematodes. The chapter focuses on the free-living Caenorhabditis elegans and the pig parasite Ascaris suum. The superb genetics and ease in obtaining DNA clones containing desired gene sequences make C. elegans the system of choice for genetic and molecular biological studies. Greater than 50% of the cells in a mature C. elegans male are sperm. When C. elegans males are squashed under hydraulic force, they burst open and release their sperm into the surrounding medium under conditions where other tissues remain relatively intact. This permits straightforward purification of near-homogeneous sperm, the vast majority of which are in the spermatid stage. Ascaris offers three principal advantages over C. elegans for the study of sperm cell biology. A robust Ascaris male contains 5 X l07 spermatids in its seminal vesicle, compared with 3 X l03 in a virgin C. elegans male. The volume of each spermatid from Ascaris is about 10-fold greater than its counterpart from C. elegans. Activation in Ascaris produces motile spermatozoa with a highly ordered cytoskeleton composed of major sperm protein (MSP) filaments grouped into long, branched fiber complexes that can be viewed in real time in live cells by light microscopy.