Histochemical and Ultracytochemical Studies of the Spermatids and Sperm of Ascaris lumbricoides var. suum1

Abstract

Considerable confusion has existed concerning the nature and function of the refringent cone and a series of vesicles found between the cone and the plasma membrane in the sperm of Ascaris sp. (Nematoda). In the present study histochemical and ultracytochemical techniques, at both the light and electron microscopic levels, have been used in order to characterize these cellular components in the spermatids and spermatozoa of Ascaris lumbricoides var. suum (A. suum). It has been demonstrated that the vesicles, believed to be of Golgi origin, fuse with the plasmalemma of the mature sperm and undergo dehiscence releasing their contents into the lumen of the female genital tract. These vesicles exhibit a positive PAS reaction at both the light and electron microscope levels. They further exhibit a positive reaction for acid phosphatase. The refringent cones do not exhibit a positive reaction for acid phosphatase and only show small loci of reaction product for the PAS test. The refringent cones do exhibit an orange fluorescence, which is indicative of RNA, when the cells are stained with acridine orange. However, this fluorescence is found in cells treated with ribonuclease; but, is not present in cells treated with trypsin. While the refringent cone resisted enzymatic digestion with ribonuclease, electron dense spheres found associated with the nucleus were partially extracted. The results of this study suggest that the vesicles (proacrosomal vesicles) may be acrosomal in nature but lend no support to the thesis that the refringent cone is the acrosome. This work further suggests that the sperm of A. summ contributes RNA to an egg at fertilization.