Iodination of Surface Components of the Spheroidal and Ameboid Spermatozoa of Ascaris suum (Nematoda)1

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Abstract
The protein constituents and iodinatable components of the spheroidal and ameboid forms of Ascaris spermatozoa were characterized by SDS[sodium dodecylsulfate]-gel electrophoresis, lactoperoxidase iodination and [125I]-diazodiiodosulfanilic acid (DD125ISA) labeling. Electrophoresis of spermatozoan total proteins on SDS-gels revealed 16 bands; 2 represent 1 major polypeptide (18,400 MW) and 1 major periodic acid-Schiff staining glycoprotein (12,000 MW). The spheroidal and ameboid spermatozoa shared 4 major components iodinatable by lactoperoxidase and DD125ISA methods. Three of these components have approximate MW of 51,000, 55,000 and 62,000, respectively. The MW of the 4th component was extremely large as suggested by its position near the top of SDS-gel. In both forms 3 small MW components (10,000, 12,000 and 18,400 MW) minimally iodinated by lactoperoxidase, were more extensively labeled with DD125ISA. The ameboid spermatozoa differed from the spheroidal form in showing a decrease in iodination of the slowest electrophoretic band and in the presence of 2 iodinatable components (greater than 66,000 MW) not detectable in the spheroidal form. These differences were evident in iodination profiles of both lactoperoxidase and DD125ISA methods. Both spheroidal and ameboid spermatozoa contain 2 molecular species of Conconavalin A (Con A) receptors identified by histochemical staining after electrophoresis on SDS-gels. The electrophoretic mobilities of these 2 Con A receptors are similar in the 2 forms of spermatozoa and are characterized by large MW; one receptor has a MW of 62,000, and the second has a MW greater than 66,000.