Amino acid and lipid composition of refringent granules from the ameboid sperm of Ascaris suum (Nematoda)

Summary

Transformation of the spermatozoon of Ascaris suum from a spheroidal to an ameboid cell is associated with the formation of a motile pseudopodium and coalescence of the intracellular refringent granules. The pseudopodia of the ameboid spermatozoa contain filaments organized into dense patches, bundles, web-like or lace-like networks, as observed by electron microscopy.

The morphology and chemistry of the refringent granules were investigated in subcellular fractions enriched for these structures. Isolated refringent granules were heterogeneous in size measuring from 0.5×0.6 to 2.3×3.5 μm. Each granule is surrounded by a 110 Å thick layer. During fusion, the surfaces of the refringent granules form small extensions resembling micropodia. The process of fusion occurs at many sites on a given granule and simultanenous fusion of several granules was commonly observed.

Amino acid analyses of the refringent granule proteins (RGP's) indicated: they are rich in aspartic acid or asparagine (48%), leucine (10%), serine (19%) and aromatic amino acids (11%). Gas-liquid chromatographic analyses of alditol acetate derivatives of monosaccharides released by mild acid hydrolysis showed the predominant sugars to be glucose (7.3 μg/mg protein), galactose (9.2 μg/mg) and N-acetylglucosamine (5.5 μg/mg). Lipid analyses indicated a complex mixture of glycerides, ascarosides and waxes, together with a major component that resembled free fatty acid in mobility on TLC.