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Alteration of hemolymph polypeptides in Manduca sexta larvae parasitized by Cotesia congregata : A two‐dimensional electrophoretic analysis and comparison with major bacteria‐induced proteins
Author(s) -
Beckage Nancy E.,
Nesbit Dorothy J.,
Nielsen Barbara D.,
Spence Kemet D.,
Barman Miel A. E.
Publication year - 1989
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940100104
Subject(s) - hemolymph , manduca sexta , biology , parasitism , microbiology and biotechnology , gel electrophoresis , polyacrylamide gel electrophoresis , manduca , biochemistry , botany , host (biology) , larva , ecology , enzyme
Analyses using one‐dimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) previously demonstrated that parasitization by the braconid wasp Cotesia congregata significantly alters the normal hemolymph polypeptide profile of host Manduca sexta larvae. In the present study two‐dimensional gel analyses corroborated our earlier findings and provided additional evidence that multiple parasitism‐specific polypeptides were induced, which varied according to the stage of development of the wasps. Parasitization additionally elicited changes in the total protein concentration detected in the blood. Initially an elevation was observed, with newly parasitized larvae exhibiting a twofold elevation in hemolymph protein concentration by 12–24 h postoviposition. In contrast, terminal‐stage hosts with second instar parasites had significantly less protein in the hemolymph, likely due to reduced growth and inhibition of arylphorin synthesis by the fat body during the final stages of parasitism. Comparison of the array of hemolymph polypeptides produced in unparasitized larvae injected with 10 6 cells of the gram‐negative bacterium Enterobacter cloacae with those proteins induced by parasitization indicated the two classes are different. Our findings confirm that the hostresponse to parasitism is a specific one, and not mimicked by bacterial challenge. Duringshort‐term in vitro culture of wasp larvae dissected from the host hemocoel, several proteins were detected in the medium using SDS ‐ PAGE, with their appearance in vitro suggestive of secretion by the wasps in vivo. Moreover, hemolymph from the parasites had significant amounts of putative host proteins, including an arylphorin ‐ like polypeptide and a protein with a mobility similar to that of insecticyanin. Thus, a dynamic interchange of proteins may occur, with the parasites accumulating host proteins while simultaneously secreting a variety of factors into the host hemocoel.