Chorionic peroxidase activity in the eggs of the fish Tribolodon hakonensis

Abstract

AbstractPeroxidase activity was ultracytochemically demonstrated in the vitelline and fertilization envelopes of eggs of the fish Tribolodon hakonensis. The vitelline envelope (VE) was morphologically divided into five layers, from the first to the fifth, numbered in order from the outside of the VE toward the interior, but the micropylar and surrounding region lacked the first layer. Peroxidase activity was localized in the first and second layers, but was much stronger in the latter than in the former. Phosphotungstic acid (PTA) staining was positive in the first layer alone. During the elevation of the fertilization envelope (FE) the peroxidase activity was translocated into the first layer of the FE from the second layer. This translocation resulted in much weaker activity or negativity in the FE second layer. In the micropylar and surrounding region, however, peroxidase activity remained unchanged, and there was no translocation. Transformation of the VE into the FE led to an alteration in the thickness of each layer and in the cytochemical nature of the first layer. There was almost no PTA staining in the FE first layer, except for a few scattered positive spots. A purified and lyophilized VEs‐ or FEs‐NaI‐H2O2 system exerted a cell‐killing effect on three bacterial species tested.