Quarterly Journal of Microscopical Science, Vol s3-90, 391-399, Copyright © 1949 by Company of Biologists

Alkaline Phosphatases and the Cycle of Nucleic Acids in the Gonads of Some Isopod Crustaceans

¹ Centro di Citogenetica del C.N.R. Università di Napoli

1. The distribution of alkaline phosphatases and their relation to nucleic acids have been investigated by means of Gomori's technique in the gonads of Isopod Crustaceans (Asellus aquaticus and some Cymothoids).

2. Alkaline monophosphatases are distributed over the Feulgen-positive structures, in nucleolus, and in the cytoplasm of young oocytes. They disappear from every place, except nucleoli, during yolk formation. The close coincidence of their localization with that of nucleic acids indicates that they are involved in the metabolism of the latter. The cytoplasmic localization is probably connected with RNA distribution only where this is being actively metabolized.

3. RNA diphosphatases have a similar distribution; they are present where the acid is present, but they do not follow so closely its cycle. Contrary to monophosphatases, they do not disappear gradually from the cytoplasm of the oocyte, where RNA does so.

4. DNA diphosphatases are partially independent from DNA, because they are present also in some Feulgen-negative structures (cytoplasm and nucleolus). As the RNA diphosphatases, they do not disappear gradually during vitellogenesis.

5. Diphosphatases show also a depolymerizing action on DNA. It seems more likely that this fact is due to a nucleasic action intrinsic in diphosphatases than to an association of these enzymes with a nuclease.

6. The interpretation of diphosphatases as a storage of phosphorylizing enzymes in the cell is discussed.

7. The possibility that Gomori's reaction of diphosphatases fails to show their exact localization in the cell is considered, and, as far as the present material is concerned, discarded.