THE ULTRASTRUCTURAL LOCALIZATION OF ACID PHOSPHATASE IN THE OVARY OF DROSOPHILA MELANOGASTER
Glutaraldehyde-fixed ovaries from wild type Drosophila melanogaster were incubated for acid phosphatase activity and subsequently prepared for ultrastructural examination. Control tissues were incubated without the inclusion of the substrate. Cellular preservation was confirmed by comparing incubated tissues with preparations that lacked the incubation period altogether. A final processing schedule was developed that produced minimal to totally absent precipitation of non-specific enzyme product. During previtellogenesis, acid phosphatase-containing vesicles were found in close proximity to the Golgi region of follicle cells. Enzymatic activity was seen within GERL, located at the innermost or "trans" aspect of the Golgi. Smooth membranes containing acid phosphatase were also shown to be in close contact with lipid vesicles. These lipid vesicles eventually degenerated during vitellogenesis. Previtellogenic nurse cells exhibited slight acid phosphatase activity within Golgi-associated vesicles. No activity was found within the oocyte at this time. During vitellogenesis, acid phosphatase-positive lysosomes were present in all follicle cells not in contact with the oocyte. Smaller vesicles, resembling lysosomes, lacked enzyme product. Late vitellogenesis was characterized by the breakdown of follicle cells that were in contact with nurse cells. Microvilli-like extensions from nurse cells were seen adjacent to the degenerating follicle cells, along with enzymatic activity in the space between these two cell types. In nurse cells furthest away from the oocyte, a proliferation of smooth endoplasmic reticulum was noted in the peripheral nurse cell cytoplasm. Nurse cells in contact with both follicle cells and the oocyte lacked smooth endoplasmic reticulum, but possessed vesicles containing acid phosphatase in their peripheral cytoplasm. Following vitellogenesis, enzymatic activity was located in the intercellular space between nurse cells. Activity was also present along the outer region of ring canals, which are continuous with nurse cell plasma membranes. Autophagic activity was indicated by a marked increase of acid phosphatase-containing cytolysomes within nurse cells. Nurse cells eventually collapsed, having exhausted their contents into the oocyte by way of the ring canals.
ALTMAN, LAWRENCE GENE, "THE ULTRASTRUCTURAL LOCALIZATION OF ACID PHOSPHATASE IN THE OVARY OF DROSOPHILA MELANOGASTER" (1982). ETD Collection for Fordham University. AAI8219229.