Acid phosphatase activity in the larval salivary glands of developing Drosophila melanogaster.

Authors

  • Helen E. Jones,

    Corresponding author
    1. Department of Biochemistry, University of Wales College of Cardiff, UK. CF1 1XL
    Search for more papers by this author
    • Tenovus Institute for Cancer Research, University of Wales College of Medicine, Heath Park, Cardiff, CF4 4XX, U.K.

  • Ivor D. Bowen

    1. School of Pure and Applied Biology, University of Wales College of Cardiff, UK. CF1 1XL
    Search for more papers by this author

Department of Biochemistry, University of Wales College of Cardiff, UK. CF1 1XL

Abstract

Both the biochemical profile and the optical and fine structural localization of acid phosphatase activity in the larval salivary glands of developing Drosophila melanogaster is described. Biochemically, acid phosphatase shows peak activity in the glands of feeding larvae, followed by a marked decline. Directly preceding the onset of cell histolysis however, enzyme activity increases 1.5 fold and is maintained at this level. Histochemically, acid phosphatase activity initially appears as discrete point or lysosomal sources. As development proceeds, an intense and diffuse form of enzyme is seen, accompanying an extremely vacuolated cytoplasm. Ultrastructurally, the enzyme is located in lysosomes, Golgi elements, multivesicular bodies and both within, and on the extracisternal surface of the rough endoplasmic reticulum. This extracisternal or cytosolic form appears directly preceding cell lysis and eventually shows a comprehensive cellular distribution. Large numbers of acid phosphatase positive haemocytes are attached to the basal glandular surface at all developmental stages. In morphologically intact gland cells, discrete extracisternal enzyme activity appears associated with local areas of degradation.

Ancillary