Histochemical Studies on Hymenolepis microstoma (Cestoda : Hymenolepididae)

Abstract

The histochemical distribution of glycogen, polysaccharide-protein complexes, acid and alkaline phosphatases, nucleic acids, amino acids, and proteins in adult forms of Hymenolepis microstoma, a tapeworm infecting the bile duct of mice, has been investigated. Glycogen is found primarily in the parenchyma, that observed in the scolex is limited to the radial muscles of the suckers. The cuticula shows no glycogen, but it does contain a PAS-positive material that is probably a mucoprotein. A comparison is made between the degree of reaction to the PAS technique in the cuticula of H. diminuta and H. nana and that of H. microstoma. Eggshell formation in H. microstoma follows essentially the same pattern as that reported by other investigators for a nontanned eggshell. The distribution of the phosphatases is primarily cuticular. In addition, alkaline phosphatase activity is found in the subcuticula and in the walls of the excretory ducts. Acid phosphatase appears to be confined to the cuticula; the greatest indication of activity of this enzyme is seen in the outermost portions of the cuticula. The small amount of basic protein found in H. microstoma is confined to the eggshell globules within the vitellaria and the yolk masses and cytoplasm within oocytes. High concentrations of RNA are present in the cells of the parenchyma and subcuticula of the neck region, maturing gonads, and developing oncospheres. DNA is confined to the nuclei of all tissues under investigation. The literature is replete with reports concerning the histochemistry and physiology of various members of the cestode genus Hymenolepis, notably that of H. diminuta and H. nana. Recent investigations by Dvorak, Jones, and Kuhlman (1961), Hassain and Jones (1963), Dvorak and Jones (1963), Litchford (1963) and Bogitsh (1963a) have drawn attention to a third member of this genus, H. microstoma. Unlike H. diminuta and H. nana, H. microstoma inhabits the bile duct of the mouse rather than the intestine proper. This paper presents some histochemical studies of H. microstoma, thereby launching a histochemical comparison of this worm with H. diminuta