Induction of novel proteins in Manduca sexta and Blaberus giganteus as a response to fungal challenge
Journal of Invertebrate Pathology
The induction of proteins in the tobacco hornworm larvae, Manduca sexta, and the adult tropical cock- roach, Blaberus giganteus, was examined after chal- lenge with cell walls of the entomopathogenic fungus Metarhizium anisopliae or the yeast, Saccharomyces cerevisiae. This was compared to induction of proteins after challenge with �-1,3-glucan or cell walls from the bacterium Micrococcus lysodeikticus. Induction of pro- teins was examined in live insects, in vitro cultures of fat bodies excised from insects, or an embryonic cell line from M. sexta, MRRL-CH-1. Challenge of fifth instar larvae by injection with S. cerevisiae resulted in the induction of 14- and 33-kDa proteins after 24 hr. Challenge of fat bodies with M. anisopliae cell walls resulted in the induction of several proteins which were not induced after challenge with �-1,3-glucan or M. lysodeikticus. These inducible proteins did not im- munoreact with M. sexta alaserpin or M13 (hemolin) antibodies. However, one of the proteins (ca. 33 kDa) induced in M. sexta by S. cerevisiae, �-1,3-glucan, M. anisopliae cell walls, or cell walls of M. lysodeikticus immunoreacted with antibodies for scolexin. Over 300 protein species were synthesized by B. giganteus fat bodies after a 6-hr incubation and approximately 10 novel proteins were observed after challenge with fungal cell walls. M. sexta cell cultures also responded to chal- lenge with fungal cell walls by synthesizing several novel proteins. The results suggest that holometabolous and hemimetabolous insects synthesize novel proteins in re- sponse to fungal challenge and that sites of synthesis may be in different cell types (fat bodies or epidermal cells).
Bidochka, M.J., R.J. St. Leger and D.W. Roberts. 1997. Induction of novel proteins in Manduca sexta and Blaberus giganteus as a response to fungal challenge. J. Invertebrate Pathology 70: 184-189.