Cryoprotective role of polyols independent of the increase in supercooling capacity in diapausing adults of Pyrrhocoris apterus (Heteroptera: Insecta)
Language English Country England, Great Britain Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
11567899
DOI
10.1016/s1096-4959(01)00441-9
PII: S1096495901004419
Knihovny.cz E-resources
- MeSH
- Time Factors MeSH
- Adaptation, Physiological * drug effects MeSH
- Hemolymph drug effects metabolism MeSH
- Heteroptera drug effects growth & development metabolism MeSH
- Cryoprotective Agents metabolism pharmacology MeSH
- Linear Models MeSH
- Survival Rate MeSH
- Cold Temperature * MeSH
- Organ Specificity MeSH
- Gas Chromatography-Mass Spectrometry MeSH
- Polymers metabolism pharmacology MeSH
- Ribitol pharmacology MeSH
- Sorbitol pharmacology MeSH
- Aging physiology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Cryoprotective Agents MeSH
- Polymers MeSH
- polyol MeSH Browser
- Ribitol MeSH
- Sorbitol MeSH
Diapausing cold-acclimated adults of the bug Pyrrhocoris apterus accumulate four 'winter' polyols, ribitol, sorbitol, mannitol and arabinitol, in total concentrations of up to 100 mM. The accumulation started only when the temperatures dropped below a threshold of +5 degrees C in laboratory acclimated insects. The supercooling capacity (SCP) was not affected by polyol accumulation and remained constant at approximately -17 degrees C. Cold hardiness, measured as survival time (Lt50) at -15 degrees C, increased from approximately 1 day to approximately 1 week in parallel with polyol accumulation. There was a tight correlation (r=0.98) between the concentration of 'winter' polyols in haemolymph and Lt50(-15). When a mixture of ribitol and sorbitol was injected into the haemolymph of the bugs acclimated to +5 degrees C, the concentration of polyols increased from 2.5 to 83.1 mM in haemolymph, or from 0.07 to 6.61 microg/mg of fresh weight in the whole body, the SCP remained unchanged and survival after exposure to -14 degrees C for 3 days increased approximately three-fold in comparison to untreated controls. Such results were interpreted as evidence for the cryoprotective role of accumulated polyols independent of the depression of SCP. Acclimation protocol using thermoperiod, mimicking daily temperature oscillations, resulted in moderately lower SCP, higher sum of polyols accumulated and significantly longer Lt50(-15) than at acclimation protocol with constant temperatures.
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