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Major plasma proteins of larvae of the southwestern corn borer, Diatraea grandiosella
Author(s) -
Lenz C. J.,
Venkatesh K.,
Chippendale G. M.
Publication year - 1987
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.940050406
Subject(s) - hemolymph , biology , molecular mass , isoelectric focusing , isoelectric point , biochemistry , gel electrophoresis , leucine , polyacrylamide gel electrophoresis , blood proteins , instar , larva , microbiology and biotechnology , amino acid , botany , enzyme
The major protein fraction of the larval hemolymph of the southwestern corn borer, Diatraea grandiosella , was shown to be composed of approximately six native proteins, and accounted for up to 55% of the plasma proteins. The apparent molecular weights of these proteins ranged from 350,000 to 500,000, as determined by nondenaturing electrophoresis at a neutral pH. Lower apparent molecular weights were obtained when the major protein fraction was subjected to electrophoresis at a high pH under nondenaturing conditions, indicating that these proteins dissociated under alkaline conditions. The isoelectric points of the major hemolymph proteins fell between 5.6 and 5.9. Denaturing electrophoresis and two‐dimensional electrophoresis showed that the native proteins were composed of subunits having apparent molecular weights of 78,000, 84,000, and 87,000. These subunits were the major labeled polypeptides found in the hemolymph of feeding last instar larvae 24 h after they had been injected with [ 3 H]leucine. They were also the major polypeptides synthesized when the fat body of last instar prediapausing larvae was incubated in vitro for 4 h in Grace's medium containing [ 3 H]leucine. Immunoelectrophoresis confirmed that the major hemolymph proteins were present in the larval fat body. In addition, these proteins were the major proteins present in the hemolymph of diapasuing larvae.