title: Hymenolepis diminuta: metacestode-induced reduction in the synthesis of the yolk protein, vitellogenin, in the fat body of Tenebrio molitor.
abstract: Vitellogenin synthesis by the fat body has been monitored using in vitro culture and immunoprecipitation. This system was found to be efficient for measuring vitellogenin production in both non-infected Tenebrio molitor and those infected with Hymenolepis diminuta. In fat bodies from infected beetles, vitellogenin production was decreased by up to 75% (day 24 post-infection) and, at all times investigated, vitellogenin synthesis was significantly below control levels (days 3-30 post-infection). Incubating fat bodies from control insects with isolated metacestodes indicated that this may be a direct effect by the parasite which is developmental stage-specific. Stage II, but not Stage III-IV, not heat-killed parasites could bring about this decrease in vitellogenin. In addition, these effects may be density dependent within the range of 2-20 parasites per fat body; only 2 metacestodes were necessary to cause a significant decrease. Since metacestodes do not take up vitellogenin, nor limit the amount of [14C]leucine available to the fat body for vitellogenin production, it is conceivable that the parasite produces a potent inhibitor of vitellogenin synthesis, or a molecule which induces cells within the fat body.
authors.affiliation: Centre for Applied Entomology and Parasitology, Department of Biological Sciences, Keele University, UK.
authors.forename: T J
authors.initials: TJ
authors.lastname: Webb
authors.forename: H
authors.initials: H
authors.lastname: Hurd
mesh_terms: D000818:Animals; D005216:Fat Body / Q000378:metabolism*; D005260:Female; D006790:Host-Parasite Interactions; D006926:Hymenolepis / Q000502:physiology*; D007930:Leucine / Q000378:metabolism; D008297:Male; D009924:Organ Culture Techniques; D011233:Precipitin Tests; D013712:Tenebrio / Q000378:metabolism / Q000469:parasitology*; D014818:Vitellogenesis; D014819:Vitellogenins / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D014819:Vitellogenins; D007930:Leucine