THE ULTRASTRUCTURAL LOCALIZATION OF PHOSPHATASES IN THE NEURONES OF THE SNAIL, HELIX ASPERSA

Accumulation and identification of lipofuscin-like pigment in the neurons of Bulla gouldiana (Gastropoda: Opisthobranchia)

A few reports suggest that pigmented granules found in molluscan neurons accumulate with age as do lipofuscin granules in vertebrate cells; however, no reports on molluscan neurons include detailed descriptions of granule accumulation or histochemical tests to identify the pigment as lipofuscin-like. In this study light microscope observations of living ganglia from 1.7, 2.7, and 3.0 cm and larger (shell length) sized Bulla gouldiana showed an increasing accumulation of orange-red pigment in the perikaryon corresponding to increasing shell size (i.e. age). With the electron microscope similar results were obtained, and lipofuscin-like granules were seen in the nerve cell cytoplasm of veliger larvae and in all adult sized Bulla. Staining with Sudan black B, Nile blue, chrome alum hematoxylin, PAS reagents, and exposure of the neurons to u.v. light to observe subsequent autofluorescence, yielded positive results in the areas of pigmented granule accumulation. Thus, the brillant orange-red granules that accumulate with age in the peripheral cytoplasm of adult Bulla neurons, and which are probably also present in larval stages, chemically resemble the lipofuscin granules of vertebrates. Similarities and differences between molluscan pigmented granules and vertebrate lipofuscin granules, in relation to structure and mechanisms of development and accumulation, are discussed.

Acid phosphatase localization in neurons of Bulla gouldiana (Gastropoda: Opisthobranchia

The organization of the ganglia and the ultrastructure of the neurons of Bulla gouldiana are similar to those described for other molluscs. Acid phosphatase positive reactions were found in the large pigmented granules, small dense bodies, multivesicular bodies, and Golgi lamellae and associated vesicles. The small dense bodies and multivesicular bodies may be stages in the formation of the larger pigmented granules which are interpreted as lysosomes. Comparison is made between the pigmented granules in Bulla and the lipofuscin bodies of vertebrate neurons. The possible involvement of these pigmented granules in the hyperpolarization of Bulla and Aplysia neurons to light is discussed.

Distribution of phosphatases in the golgi region and associated structures of the thoracic ganglionic neurons in the grasshopper, Melanoplus differentialis

The neuronal perikarya of the grasshopper contain sudanophilic lipochondria which exhibit an affinity for vital dyes. These lipochondria are membrane-delimited and display acid phosphatase activity; hence they correspond to lysosomes. Unlike those of most vertebrates, these lysosomes also hydrolyze thiamine pyrophosphate and adenosine triphosphate. Like vertebrate lysosomal "dense bodies," they are electron-opaque and contain granular, vesicular, or lamellar material. Along with several types of smaller dense bodies, they are found in close spatial association with the Golgi apparatus. The Golgi complexes are frequently arranged in concentric configurations within which these dense bodies lie. Some of the smaller dense bodies often lie close to or in association with the periphery of dense multivesicular bodies. Further, bodies occur that display gradations in structure between these multivesicular bodies and the dense lysosomes. Acid phosphatase activity is present in the small as well as the larger dense bodies, in the multivesicular bodies, and in some of the Golgi saccules, associated vesicles, and fenestrated membranes; thiamine pyrophosphatase is found in both the dense bodies and parts of the Golgi complex. The close spatial association of these organelles, together with their enzymatic similarities, suggests the existence of a functional or developmental relationship between them.