Studies on the lipid metabolism of cestodes
Doctor of Philosophy
The problem of the energy relationship is fundamental in any investigation of animal physiology. Endoparasitic helminths present a rather unique ecological situation since the energy sources and substrates for the parasite are dependent more upon the vagaries of the individual species and even strain of host animal in which they are found than on the individual efforts of the parasite. Fat metabolism is a good criterion for the evaluation of several aspects of the relationships between the host and the parasite. It is sensitive to both anaerobic and aerobic metabolic activities and because of its stability it is also effective in analyzing the response of the parasite to various environmental changes. Some aspects of the metabolism of the fat component of the rat cestode, Hymenolepis diminuta, are presented here. Considering the chemical pathways involved in the deposition of fatty materials it is soon realized that investigations on intermediary lipid metabolism are made quite complex by the fact that in the study of the chemical reactions involving fats, it is necessary to adequately consider those involving carbohydrates. A detailed elucidation of the basic metabolic pathways in the parasite is an essential basis for the clear understanding of the energy relationships between parasite and host. For this reason, an extensive review of the literature with particular attention to the development of the current concept of fat metabolism is presented. This, it is hoped, will clarify not only the mechanisms involved in the immediate area of intermediary metabolism, but also it will illustrate the importance of other metabolic areas as seen through the activity of the basic two-carbon unit.