Journal of Comparative Physiology B

, Volume 164, Issue 3, pp 247–255

Enzyme activity profiles in an overwintering population of freeze-tolerant larvae of the gall fly, Eurosta solidaginis

  • D. R. Joanisse
  • K. B. Storey
Article

DOI: 10.1007/BF00354086

Cite this article as:
Joanisse, D.R. & Storey, K.B. J Comp Physiol B (1994) 164: 247. doi:10.1007/BF00354086

Abstract

The activity of some enzymes of intermediary metabolism, including enzymes of glycolysis, the hexose monophosphate shunt, and polyol cryoprotectant synthesis, were measured in freeze-tolerant Eurosta solidaginis larvae over a winter season and upon entry into pupation. Flexible metabolic rearrangement was observed concurrently with acclimatization and development. Profiles of enzyme activities related to the metabolism of the cryoprotectant glycerol indicated that fall biosynthesis may occur from two possible pathways: 1. glyceraldehyde-phosphate → glyceraldehyde → glycerol, using glyceraldehyde phosphatase and NADPH-linked polyol dehydrogenase, or 2. dihydroxyacetonephosphate → glycerol-3-phosphate → glycerol, using glycerol-3-phosphate dehydrogenase and glycerol-3-phosphatase. Clearance of glycerol in the spring appeared to occur by a novel route through the action of polyol dehydrogenase and glyceraldehyde kinase. Profiles of enzyme activities associated with sorbitol metabolism suggested that this polyol cryoprotectant was synthesized from glucose-6-phosphate through the action of glucose-6-phosphatase and NADPH-linked polyol dehydrogenase. Removal of sorbitol in the spring appeared to occur through the action of sorbitol dehydrogenase and hexokinase. Glycogen phosphorylase activation ensured the required flow of carbon into the synthesis of both glycerol and sorbitol. Little change was seen in the activity of glycolytic or hexose monophosphate shunt enzymes over the winter. Increased activity of the α-glycerophosphate shuttle in the spring, indicated by greatly increased glycerol-3-phosphate dehydrogenase activity, may be key to removal and oxidation of reducing equivalents generated from polyol cryoprotectan catabolism.

Key words

Insect freeze tolerance Enzymes Metabolism Cryoprotectant synthesis Eurosta solidaginis 

Abbreviations

6PGDH

6-Phosphogluconate dehydrogenase

DHAP

dihydroxy acetone phosphate

F6P

fructose-6-phosphate

F6Pase

fructose-6-phospha-tase

FBPase

fructose-bisphosphatase

G3P

glycerol-3-phosphate

G3Pase

glycerol-3-phosphate phophatase

G3PDH

glycerol-3-phosphate dehydrogenase

G6P

glucose-6-phosphate

G6Pase

glucose-6-phosphatase

G6PDH

glucose-6-phosphate dehydrogenase

GAK

glyceraldehyde kinase

GAP

glyceraldehyde-3-phosphate

GAPase

glyceraldehyde-3-phosphatase

GAPDH

glyceraldehyde-3-phosphate dehydrogenase

GDH

glycerol dehydrogenase

GPase

glycogen phosphorylase

HMS

hexose monophosphate shunt

LDH

lactate dehydrogenase

NADP-IDH

NADP+-dependent isocitrate dehydrogenase

PDHald

polyol dehydrogenase, glyceraldehyde activity

PDHgluc

polyol dehydrogenase, glucose activity

PFK

phosphofructokinase

PGI

phosphoglucoisomerase

PGK

phosphoglycerate kinase

PGM

phosphoglucomutase

PK

pyruvate kinase

PMSF

phenylmethylsulfonylfluoride

SoDH

sorbitol dehydrogenase

Vmax

maximal enzyme activity

ww

wet weight

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • D. R. Joanisse
    • 1
    • 2
  • K. B. Storey
    • 1
    • 2
  1. 1.Institute of BiochemistryCarleton UniversityOttawaCanada
  2. 2.Department of BiologyCarleton UniversityOttawaCanada