THE SELECTIVE ACCUMULATION OF BLOOD PROTEINS BY THE OOCYTES OF SATURNIID MOTHS

¹ Zoological Laboratory, University of Pennsylvania, Philadelphia 4, Penna

1. At least seven proteins detectable by immunological techniques in the blood of the Cecropia moth have antigenic counter-parts in the oocytes produced by the female moth. While several oocyte antigens are undetectable in the blood of the female pupa, all of the proteins thus far observed in the blood are also present in the oocyte. Four out of five proteins of non-insectan origins, after being injected into the blood of the Polyphemus moth were detectable in the oocyte. Thus, the oocyte appears to accumulate almost all of the proteins present in the blood.

2. When the blood of Cecropia is injected into females of the Polyphemus moth, antigen 7, the "female protein," and antigen 3, a carotenoid protein, become distributed between the blood and the oocytes of the host in a manner quantitatively similar to their normal distribution in Cecropia. These two oocyte proteins may therefore be derived exclusively from the blood, rather than being synthesized to an appreciable extent in the ovary. The capacity of these proteins to combine with homologous antibodies was not detectably altered during their transmission from the blood to the oocyte.

3. Measurements of the concentrations of several proteins in the oocyte, relative to their concentrations in the blood, indicate that the mechanism of protein accumulation is selective. Of the proteins studied, the female protein was the most avidly accumulated, while the non-insectan proteins were detectable in the oocyte in relatively small amounts.

4. The proteins derived from the blood are probably localized primarily in the yolk spheres of the oocyte. Protein accumulation in this case therefore entails both the penetration of the oocyte surface and association with a cytoplasmic particle.