ISSN:
0739-4462
Keywords:
Cotesia congregata
;
NMR
;
13C
;
fat body metabolism
;
pyruvate
;
Krebs cycle
;
lipogenesis
;
Chemistry
;
Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Metabolism of fifth instar Manduca sexta larvae was significantly altered during parasitization by Cotesia congregata. The in vivo 13C natural abndance spectrum and histological examination of the fat body demonstrated significantly reduced fat levels and increased deposition of glycogen in parasitized insects. 1H NMR analysis demonstrated that the free amino acid level was reduced in the hemolymph of parasitized larvae, but control and parasitized insects had similar levels of trehalose. [13C]2-pyruvate injected into the dorsal vessel was incorporated into numerous metabolites including amino acids, Krebs cycle intermediates, trehalose, and fat. In control larvae pyruvate was incorporated primarily into fat following oxidation to CoASAc. Pyruvate was metabolized slower in parasitized larvae and following decarboxylation to oxaloacetate was metabolized by Krebs cycle and incorporated into amino acids. Only small amounts of trehalose were synthesized from pyruvate in control and parasitized larvae and glycogen synthesis was not observed. Analysis of hemolymph indicated no net synthesis of glucose by gluconeogenesis. Control and parasitized larvae incorporated [13C]1-glucose primarily into trehalose. Control larvae also synthesized fat from gulcose. In contrast, fat synthesis was not observed in parasitized insects which incorporated glucose into glycogen. Differences in glucose metabolism, therefore, appeared to explain the difference in storage metabolite levels between control and parasitized larvae.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/arch.940130112
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