Phenoloxidase, a marker enzyme for differentiation of the neural ectoderm and the epidermal ectoderm during embryonic development of amphioxus Branchiostoma belcheri tsingtaunese

The development of phenoloxidase during amphioxus embryogenesis was spectro photometrically and histochemically studied for the first time in the prese nt study. It was found that (1) PO activity initially appeared in the gener al ectoderm including the neural ectoderm and the epidermal ectoderm at the early neurala stage but not in the mesoderm or the endoderm, and (2) PO ac tivity disappeared in the neural plate cells but remained unchanged in the epidermal cells when the neural plate was morphologically quite distinct fr om the rest of the ectoderm. It is apparent that PO could serve as a marker enzyme for differentiation of the neural ectoderm from the epidermal ectod erm during embryonic development of amphioxus. (C) 2000 Elsevier Science ir eland Ltd. All rights reserved.