Giant mitochondria in the seromucous secretory cells of the accessory submandibular gland of the long-haired fruit bat, Stenonycteris lanosus.

Giant mitochondria, measuring up to 6.4 microns in diameter, are present in the seromucous secretory cells of the accessory submandibular gland of the long-haired fruit bat, Stenonycteris lanosus. These mitochondria, as well as all of the smaller ones in the same cells, contain in their matrix compartment an abundance of 33 nm threads that probably consist of protein. Some mitochondria, regardless of size, contain 5 nm helical filaments within an expanded crista. Despite their altered morphology, the enlarged mitochondria in the accessory submandibular gland of S. lanosus must be able to function normally in energy metabolism, since the secretory cells in which they are found elaborate numerous secretory granules.