Production of essential amino acids from glutamate by mycetocyte symbionts of the pea aphid, Acyrthosiphon pisum
Abstract
Glutamine was the most abundant amino acid constituent in the hemolymph of pea aphids, Acyrthosiphon pisum. While mycetocytes isolated from the aphids took up glutamine actively, the intracellular symbionts isolated from the mycetocytes scarcely took up the amino acid, and instead took up glutamic acid actively. [U- 14C]Glutamine incorporated by mycetocytes was converted into glutamate. When [ϵ- 15N]glutamine was introduced into mycetocytes, [ 15N]glutamate was found in the cytosol. These results suggested that glutamine taken up by mycetocytes was hydrolyzed into glutamic acid and ammonia, and at least a portion of ammonia was assimilated into glutamate in the cytosol, probably through reaction with α-ketoglutarate. When isolated symbionts were incubated with [ 15N]glutamic acid, the following amino acids were found highly labeled: alanine, aspartic acid, glutamine, isoleucine, leucine, phenylalanine, proline and valine.
- Publication:
-
Journal of Insect Physiology
- Pub Date:
- January 1995
- DOI:
- Bibcode:
- 1995JInsP..41...41S
- Keywords:
-
- Pea aphid;
- Mycetocyte;
- Endosymbiont;
- Glutamine;
- Glutamic acid