Ultrastructural organization of the basal lamina in insect Malpighian tubules

Abstract

Relatively little is known about the structure or function of the basal lamina in insect cells. I report here the ultrastructural organization of the basal lamina in Malpighian tubule yellow region primary cells of larval stage skipper butterflies (Calpodes ethlius). The Malpighian tubules selectively filter the blood and produce a primary urine which flows down the tubule lumen into the alimentary canal for excretion. The basal lamina provides the only barrier between the Malpighian tubule cells and the blood which freely circulates within the open body cavity and it may therefore regulate which molecules and ions gain access to the tubule cells. As a first step in these studies on the structure, composition and function of the basal lamina in insect cells the ultrastructure of the basal lamina in Calpodes Malpighian tubules after conventional TEM tissue processing and poststaining has been compared with that observed following en bloc staining with a variety of electron dense stains and probes with specificity for basal lamina components.