Studies on the absorption of methionine by the rat cestode, Hymenolepis diminuta
Simmons, John E., Jr
Doctor of Philosophy
The number of species of tapeworms readily available for laboratory control is quite limited. Two species in particular seem best suited for testing the interesting hypothesis propounded by Read, Simmons, Campbell and Rothman (1960). Hymenolepis diminuta, a cestode whose normal definitive host is the wild rat, grows quite well in both albino rats and hamsters, attaining a greater size in the former (Read and Voge, 1954). Hymenolepis citelli, a parasite of ground squirrels, is morphologically very similar to H. diminuta, and while it grows quite well in hamsters, growth and development is very poor in the albino rat (Read and Phifer, 1959). Thus, a knowledge of the characteristics of absorption of amino acids by the two worms, together with a knowledge of the amino acid mixtures characteristic of the intestines of different host species, will perhaps allow direct experimental testing of the hypothesis that these factors are involved in establishment and development of a tapeworm in a particular host species. It is apparent that we still know very little concerning amino acid absorption by Hymenolepis diminuta. The present study was designed to increase our understanding of this phenomenon, especially concerning the absorption of L-methionine by this cestode. Advantage was taken of the more adequate methods described by Read, Simmons and Rothman (1960) to overcome the defects in design of experiments performed by Daugherty (1957a, 1957b) and Daugherty and Foster (1958). In addition it was hoped that such a study would reveal whether the methods employed and the species studied would be suitable in undertaking experimentation designed to answer some fundamental questions concerning the ecological relationship called "parasitism", raised by our present knowledge of amino acid permeation into tapeworms.
Microbiology; Physiology; Zoology