[
Adv Exp Med Biol,
2014]
Generally, spermatogenesis and sperm function involve widespread posttranslational modification of regulatory proteins in many different species. Nematode spermatogenesis has been studied in detail, mostly by genetic/molecular genetic techniques in the free-living Caenorhabditis elegans and by biochemistry/cell biology in the pig parasite Ascaris suum. Like other nematodes, both of these species produce sperm that use a form of amoeboid motility termed crawling, and many aspects of spermatogenesis are likely to be similar in both species. Consequently, work in these two nematode species has been largely complementary. Work in C. elegans has identified a number of spermatogenesis-defective genes and, so far, 12 encode enzymes that are implicated as catalysts of posttranslational protein modification. Crawling motility involves extension of a single pseudopod and this process is powered by a unique cytoskeleton composed of Major Sperm Protein (MSP) and accessory proteins, instead of the more widely observed actin. In Ascaris, pseudopod extension and crawling motility can be reconstituted in vitro, and biochemical studies have begun to reveal how posttranslational protein modifications, including phosphorylation, dephosphorylation and proteolysis, participate in these processes.
[
Methods Cell Biol,
1995]
In this chapter we review methods that have been developed for working with the amoeboid sperm of nematodes. Although the sperm from a number of species have been examined, we confine our discussion to the free-living Caenorhabditis elegans and the pig parasite Ascaris suum. Each of these experimental systems offers the investigator certain strengths and weaknesses, and the type of contemplated experiment determines which is most suitable. Ascaris sperm are more easily obtainable in large quantity and are, therefore, more suited for biochemical studies. Furthermore, the Ascaris sperm is much larger than its C. elegans counterpart, allowing easier light microscopic analyses. 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. Much evidence indicates that the sperm of these two systems share important similarities, and data obtained in one are frequently applicable to the other. Consequently, although the rest of this volume concerns principally C. elegans, we feel this chapter requires discussion of both C. elegans and Ascaris sperm because much of understanding of amoeboid sperm cell biology has, in fact, been obtained from Ascaris.