Granulopoiesis in tadpoles of Rana esculenta. Ultrastructural observations on the morphology and development of heterophil and basophil granules
Frank, G.
Journal of Anatomy 163: 107-116
1989
ISSN/ISBN: 0021-8782 PMID: 2606765 Document Number: 342020
The morphology and development of heterophil and basophil granules from the trunk kidneys of Rana esculenta tadpoles were studied at the electron microscopic level. Cells of the heterophil series contain granules displaying either spheroid profiles with homogeneous content (type A), or elongated profiles with a cristalloid internum (type B). Type A granules apparently originate from Golgi-derived vesicles, which, gaining slightly in size and density, transform into the mature granules. Type B granules could be traced back to vacuolate structures showing an irregular content. Their development could be traced through increasingly elongated forms with the appearance of a characteristic cristalloid core. Fully developed basophil granules are considerably larger in size than heterophil granules and contain heterogeneous interna showing a central-cortical organisation: a finely dotted medullary zone of varying density is surrounded by a sickle-shaped and lamellate cortex (type L), or a moderately dense and uniformly stippled medulla is enclosed by two diametrically opposed, cap-shaped, filamentous regions (type F). Observations on immature basophils suggest a maturation-dependent change in the internal organisation of the cortex of the type L granules from particulate to filamentous and, finally, to lamellate. The heterophil and basophil granules are compared to those in other vertebrates and possible phylogenetic aspects are discussed.