The fine structure of the salivary glands in the cockroach Gromphadorhina portentosa: Secretion

Abstract

Secretion in the salivary glands of Gromphadorhina portentosa involves three cell types: parietal cells, secretory cells, and duct cells. The organization and role of the parietal and secretory cells are here considered. Parietal cells have numerous mitochondria, indicating an active metabolic role and the subsequent production of ATP. Plasma membrane invaginations and intracellular ductules containing microvilli appear to function in the absorption of solutes from the hemolymph and finely-tapered ductules. Secretory cells contain abundant rough endoplasmic reticulum, the three forms (stacked, vesicular, and diffuse) of which appear to develop sequentially during maturation. Secretory vesicle formation is asynchronous between adjacent secretory cells, and apparently the large vesicles often coalesce. The secretory vesicles also show differing degrees of electron density, indicating distinct biochemical composition.

Morphology of the mandibular gland of the ant Paraponera clavata (Hymenoptera: Paraponerinae)

“…Nevertheless, this is an intriguing finding because secretory cells are rich in mitochondria and lipid droplets and with few rough endoplasmic reticulum, an expected cytoplasm organelle for cells producing proteins (Alberts et al, ). Otherwise, mitochondria and lipid droplets have been reported in the secretory cells of the mandibular gland of ants (Davidson, Kamariah, & Billen, ; Billen, Hashim, & Ito, ), associated with high metabolic rate (Dailey & Crang, ; Gracioli‐Vitti & Abdalla, ; Santos, Souza, Vieira, Zanuncio, & Serrão, ), as lipids are energy reserves used by mitochondria for ATP production.…”