Presence of a substance crossreacting with cortical alveolar material in “yolk vesicles” of growing oocytes of Oryzias latipes

A large number of spherical bodies, a major insoluble component of cortical alveolus, were isolated from blastulae of medaka, Oryzias latipes . Spherical body material was found to be abundant in carbohydrates, especially in galactose and hexosamine, and total carbohydrate content amounted to about 1.3 times that of protein. Immunohistochemical studies using anti‐spherical body antiserum as a probe revealed that a substance crossreacting with spherical body material was localized only in “yolk vesicles” of growing oocytes and later in cortical alveoli of full‐grown oocytes. Thus the present results identified immunochemically yolk vesicle material with cortical alveolar material, supporting the view that the yolk vesicle is a precursory structure of cortical alveolus.