1932

Abstract

Natural freeze-tolerance supports the winter survival of many animals including numerous terrestrial insects, many intertidal marine invertebrates, and selected species of terrestrially hibernating amphibians and reptiles. Freeze-tolerant animals typically endure the conversion of 50% or more of total body water into extracellular ice and employ a suite of adaptations that counter the negative consequences of freezing. Specific adaptations control the sites and rate of ice formation to prevent physical damage by ice. Other adaptations regulate cell-volume change: Colligative cryoprotectants minimize cell shrinkage during extracellular ice formation; other protectants stabilize membrane structure; and a high density of membrane transporter proteins ensure rapid cryoprotectant distribution. Cell survival during freezing is also potentiated by anoxia tolerance, mechanisms of metabolic rate depression, and antioxidant defenses. The net result of these protective mechanisms is the ability to reactivate vital functions after days or weeks of continuous freezing. Magnetic resonance imaging has allowed visual examinations of the mode of ice penetration through the body of freeze-tolerant frogs and turtles, and cryomicroscopy has illustrated the effects of freezing on the cellular and microvasculature structure of tissues. Various metabolic adaptations for freezing survival appear to have evolved out of pre-existing physiological capacities of animals, including desiccation-resistance and anoxia-tolerance.

Loading

Article metrics loading...

/content/journals/10.1146/annurev.ecolsys.27.1.365
1996-11-01
2024-03-29
Loading full text...

Full text loading...

/content/journals/10.1146/annurev.ecolsys.27.1.365
Loading
/content/journals/10.1146/annurev.ecolsys.27.1.365
Loading

Data & Media loading...

  • Article Type: Review Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error