Studies on blood Cells of the silkworms, Bombyx mori II.

Electron microscopic studies

Abstract

Ultrastructure of five kinds of blood cells of the silkworm, Bombyx mori, has been studied. Proleucocytes are primitive cells, rich in free polyrihosomes and containing a few rough endoplasmic reticulum. It is suggested that granular cells and spherule cells are differentiated from the proleucocytes. Ultrastructure of the plasmatocytes is quite similar to that of the proleucocytes. Granular cells contain well developed rough endoplasmic reticulum with dilated cisternal cavity, as well as a number of specific granules that are probably formed by the Golgi apparatus. The granular cells are active in phagocytosis and in secretion. Spherule cells usually contain several large spherical granules which are probably to be secreted out of the cells. Oenocytoides have a number of cytoplasmic free polyribosomes and inclusion bodies. There are two kinds of inclusion bodies; one is fibrous material composed of fine filaments and the other is round or oval bodies with homogeneous content. It is suggested that these inclusion bodies are proteineous materials synthesized by the free polyribosomes.