Morphological and histochemical observations on the intestinal epithelium of Ascaridia galli (Nematoda: Ascaridida)

Abstract

The intestinal epithelium of Ascardia galli has been studied with various cytological and cytochemical techniques. It consists of large epithelial cells resting on a thick collagenous basal lamina. Their luminal surface is provided with microvilli. The intestinal cells store considerable amounts of glycogen and neutral lipids. Some intracellular granular inclusions, which stain for proteins, phospholipids and lipoproteins, are distributed throughout the cytoplasm. The brush border is composed of microvilli whereas the outer surface coat consists of saliva resistant PAS-positive material. The detailed histochemical analysis of surface material has revealed that it is composed of nonacetylated acid mucopolysaccharides rich in hyaluronic acid with carboxylate polyanions. The brush border shows intense activities of acid phosphatase and glucose-6-phosphatase, moderate of ATPase, and lipase, weak of 5'-nucleotidase. Acid phosphatase-positive intracellular structures are seen in the intestinal epithelium which form distinct aggregations.

Release of hyaluronidase during in vitro development of Ascaris suum from the third to fourth larval stage

“…HA has been identi®ed as a component of nematode cuticles (Lee 1977); it was therefore suggested that the adhesion between the extracellular cuticle and the underlying cellular epidermis might involve HA, and the breaking of this cuticle±epidermal connection might be a critical step in molting. Another suggested function for the H. contortus enzyme was in the maturation of nematode digestive processes, since HA is a signi®cant component of the intestinal epithelium of nematodes (Parshad and Guraya 1978). Thus, the Ascaris suum (and possibly C. elegans) hyaluronidases may function in these critical basic developmental processes, shared by both freeliving and parasitic nematodes.…”