| Popis: |
The test cells, one of the two accessory cell groups of the ascidian oocyte, persist around the developing embryos and the hatched tadpole larvae, but their function during embryogenesis is not fully understood. We have produced monoclonal antibodies that specifically recognize the test cells in Ciona intestinalis (Takamura et al., Zool. Sci. 13: 241-251, 1996). In the present paper, we demonstrate the ultrastructural localization of the antigen reactive to one of the test cell-specific antibody UA165 by immunogold labeling. The mature test cells in Ciona intestinalis contain two types of cytoplasmic inclusions, i.e., irregular vacuoles with electron-dense cores and spherical vesicles with a moderately electron-dense content. UA165-immunogold particles specifically labels the content of the spherical vesicles. Concomitantly with larval tunic formation at the early tailbud stage, the spherical vesicles begin to rupture and the UA165 antigen is exocytosed into the perivitelline space surrounding th... |
