EFFECTS OF MICROPLITIS-CROCEIPES TERATOCYTES ON HOST HEMOLYMPH PROTEIN-CONTENT AND FAT-BODY PROLIFERATION

Qualitative and quantitative changes in haemolymph proteins in Helioth is virescens were observed in larvae injected with either Microplitis croceipes teratocytes or teratocyte secreted proteins (TSP), Haemolymp h protein titres in hosts receiving either 0.5 or 1 larval equivalent (LE) of teratocytes were similar to those of parasitized larvae, where as a single injection of 4 LE of TSP was required to induce a similar response, SDS-PAGE showed that the 82 kDa monomer of riboflavin-bindin g protein and the 74/76 kDa monomers of storage proteins were signific antly reduced in parasitized larvae and in nonparasitized larvae treat ed with TSP, Concentrations of a 155 kDa monomer (insectacyanin chromo protein) also were reduced in parasitized larvae and those injected wi th either teratocytes or TSP. Two monomers (56 and 60 kDa) were unique to parasitized larvae. Treated larvae required several days longer th an controls to reach a comparable premetamorphic stage (burrowing-digg ing), Reductions in fat body proliferation similar to those seen in pa rasitized larvae were observed in larvae treated with either 1 LE of t eratocytes, or with 2 or 4 LEs of TSP, Perivisceral fat body weights f rom larvae treated with either 0.25 or 0.5 LE of teratocytes were sign ificantly reduced, but less so than those which received 1 LE, Thus, f at body proliferation in both teratocyte- and TSP-treated larvae was i nhibited in a dose-dependent manner, Both light- and transmission elec tron microscopy observations revealed cytological differences in fat b ody tissues of larvae injected with either teratocytes or TSP from the condition observed in parasitized larvae and noninjected controls, Gr oss dissection of periviseral fat body from parasitized, teratocyte-in jected and TSP-injected larvae showed tissue much less developed and d iffering considerably in appearance from controls, Observed difference s included reduced size and/or number of lipid bodies and qualitative and quantitative changes in other cytoplasmic organelles. (C) 1997 Els evier Science Ltd.