文昌鱼表皮中酚氧化酶的超微结构定位

Ultrastructural localization of phenoloxidase in the epidermal cell of the amphioxus Branchiostoma belcheri tsingtaunese

文昌鱼是从无脊椎动物到脊椎动物的过渡类型 ,在进化上占有极重要的地位。本文以 L -多巴为底物 ,显示酚氧化酶 ( PO)存在于文昌鱼体表上皮细胞的胞质中 ,PO颗粒呈圆形均质状 ,直径在4 2 0～ 70 0 nm之间 ,电子密度较高 ,其外无膜包被。苯硫尿 ( PTU)抑制酚氧化酶反应 ,指出该反应为PO的特异性反应 ,而不是底物的自氧化或其它假阳性反应。

Phenoloxidase (PO) has been shown to be present in both invertebrates and vertebrates, yet little is known about PO in Branchiostoma belcheri tsingtauense, the lancelet or amphioxus, a cephalochordate transitional from invertebrates to vertebrates. It was shown in the present study that PO existed in the epidermal cells of the animal. Ultrastructural examination revealed that phenoloxidase reaction products, were located in the cytoplasm of epidermal cells as an homogenous, electron dense masses. This is the first report on ultrastructural localization of PO in amphioxus. PO could serve as protecting agents against environmental pathogens and foreign bodies.