Electron Microscopy of the Bacillary Band and Stichosome of Trichuris muris and T. vulpis

Abstract

The bacillary band is composed of tall columnar cells. The basal plasma membrane is folded and interdigitates with adjacent cells. The cytoplasm is filled with RNP particles and a fine endoplasmic reticulum. The apical area contains numerous mitochondria and a complex system of lamellae formed by invaginations of the plasma membrane. A homogeneous secretory mass fills the cuticular pore. The stichosome consists of a row of cells each of which partially or completely encloses the esophagus. The entire stichosome and esophagus are enclosed by a membranous sheath consisting of many fine layers. The central nucleus has many fine blebs arising from its surface. Numerous electron-dense granules are scattered in the cytoplasm. Large vesicles with connecting canaliculi occur throughout the cell. The esophageal lumen is enclosed by tubular cells. The fine structure suggests that the stichocytes may be secretory in function but no evidence of a secretion leaving the cell has been observed. The bacillary band also appears to secrete a substance through the cuticular pores but the nature of this product is undetermined. Comparison of the fine structure of the Malpighian tubules of insects and mammalian kidney tubule cells with that of the bacillary cells suggests an excretory function.[long dash]Author.