PHYSIOLOGICAL AND BIOCHEMICAL INVESTIGATIONS OF THE EGG JELLY RELEASE IN PENAEUS AZTECUS

Following contact with seawater, Penaeus aztecus ova undergo a massive release of extracortical jelly precursor material which is transformed into a layer of jelly-like material surrounding the ova. Release and dissipation of the precursors can be irreversibly inhibited by the protease inhibitors N-a-p-tosyl-L-lysine chloromethyl ketone and soybean trypsin inhibitor, implicating trypsin-like proteases in the process. Treatment with the less-specific enzyme inhibitor phenylmethyl sulfonyl fluoride also irreversibly inhibits the release of the cortical material. Jelly precursor in whole mature ovaries stain positive with PAS. Staining with alcian blue reveals acid mucopolysaccharides in the investment coat of the ova but not in the jelly precursors. Precursors isolated from whole mature ovaries are approximately 25-30% carbohydrate (anthrone sulfuric acid reaction) and 70-75% protein (Lowry's and Bradford's protein determinations). No sialic acids are detected in the isolates (thiobarbituric acid assay). Trypsin is effective in dissipating the precursor isolates. Amino acid analysis reveals high ratios of cysteic acid. Significant biochemical differences between P. aztecus egg jelly material and sea urchin egg jelly are discussed.