Ultrastructure of secretory cells in the gut of the cattle-tick Boophilus microplus

Abstract

The ultrastructural study of the secretory cells type 1 and 2 confirmed the separate identities of two secretory cell types in the gut of female B. microplus. Secretory cell type 1 (s 1) synthesized and secreted large, spherical, uniformly electrondense granules. Secretory cell type 2 (s 2) synthesized smaller, irregularly shaped and more complex granules. Another cell type, the basophilic cell, was shown to be the reorganized basal remnant of secretory cell s 2. A few of the basophilic cells retained remnant s 2 granules within their cytoplasm. In these cells the reorganized cisternae of rough endoplasmic reticulum were arranged in whorls and parallel arrays. The cells synthesized granules with a different ultrastructure and position in the cell from the earlier granules. The new secretory material may be egg proteins which are released into the haemolymph, and transported to the ovary. Another secretory cell type with smaller spherical granules was seen in the gut caeca of only two female ticks and more evidence is needed to prove its separate identity.