How does rapid cold-hardening work?

Rapid cold-hardening (RCH) is a process by which insect survival of chilling injury at sub-zero temperatures is massively increased after a short pre-exposure to a less-severe low temperature. For example, survival of a 2 h exposure to -10.1 °C by the South African Fynbos chrysomelid beetle Chirodica chalcoptera increases from 20 to 76 % after a 2 h pre-exposure to -2 °C (Terblanche et al., in press J. Insect Physiol.). Since its discovery in 1987, RCH has been described in a large number of insects and other arthropods, yet its mechanism is still largely unknown. What is known is that RCH does not involve changes in the traditional cold tolerance measure of the supercooling point; is not closely associated with Hsp70 production; and that the RCH response can be elicited by exposing insects to a variety of environmental stressors including heat shock, hypoxia and desiccation. In collaboration with the Gibbs Lab, we are using Drosophila melanogaster as a model organism that displays RCH. We are looking at the expression of RCH in response to cold and other stresses, as well as selecting lines of flies for RCH and basal cold tolerance. By using a model species, we gain access to a wealth of proteomic and genomic tools and information that is not available for non-model species like the Fynbos beetle mentioned above. Ultimately, we hope to generate a working model for the mechanisms of RCH which we can test in model and non-model species.

Roberts Lab Personnel:
Steve Roberts
Brent Sinclair
Terri Nilson
Brian Pierson