Hymenolepis diminuta: the pathophysiology of infection in the intermediate host, Tenebrio molitor
In T. molitor infected with metacestodes of H. diminuta total haemolymph free protein concentration, determined by the Lowry method, ranged from 62 to 81 mg/ml in females and was significantly lower in males (36-54mg/ml). A 477. increase was detected in female beetles 12 days or more post-infection, no such difference being detected at an earlier stage, nor in males at any age examined.
Using SDS PAGE, 13 bands were separated from haemolymph, bands 2/3 and 7/8 being present in greater concentrations in female beetles. Molecular weight determinations and histochemical evidence suggested that these proteins were vitellogenins. Densitometric analysis revealed that these bands alone were elevated in haemolymph from females 12 days post-infection, no such elevation being detected at an earlier stage, nor in infected male beetles. Infection did not affect fat body wet-weight nor protein content. However, in vitro culture of fat bodies with ^C-leucine revealed a 617 decrease in protein synthesis to be associated with infection. In vivo sequestration of labelled proteins by ovaries from infected beetles was significantly decreased, the majority of the label being detected in the vitellogenic fraction of ovary homogenates. Various parameters of fecundity were measured over a period of 30 days; total egg-volume and egg protein content were unaffected by infection. However, the second peak of egg laying was delayed, egg viability decreased and total protein content of eggs reduced in infected females. Sixteen haemolymph free amino acids were detected, total concentrations ranging from 34-84 mM. Although overall concentrations were not affected by infection, significant differenes occurred in individual amino acids, these being most marked in female beetles. The literature concerning host parasite interactions has been reviewed and it is suggested that the above pathological effects may be due to an interference by the parasite with the host endocrine
|Publication Date||Jan 1, 1985|