The wood frog, Rana sylvatica LeConte 1825, is a freeze-tolerant amphibian widely distributed in North America. Subarctic populations of this species can survive experimental freezing to temperatures below -16 °C, whereas temperate populations tolerate freezing only at temperatures above -6 °C. We investigated whether hepatocytes isolated from frogs indigenous to Interior Alaska (subarctic) or ...

Winter wheat (Triticum aestivum L. em. Thell.) is sown in the autumn and harvested the following summer, and therefore must survive subfreezing temperatures for several months. Because of autumn rains and winter snows, the plants usually are subjected to these subfreezing temperatures while growing in saturated soil. As the plants freeze, they are subjected to freezing episodes that may vary in...

in this study, accumulation of h2o2, malondialdehyde (mda) (as cold-induced oxidative stress indicators), the transcript levels of dehydrin and beta-glucosidase genes (involved in metabolic responses) was evaluated in chickpea cv. jam, using qrt-pcr during control, cold acclimation (ca), cold stress (cs), recovery, and freezing phases. results showed the existence of wide range of genetic capac...

We studied the mechanism of cold acclimation of Jerusalem artichoke (Helianthus tuberosus L.) tubers with special reference to the role of the cell wall. During the cold-acclimation process from September to January, the freezing tolerance of tubers increased from -2.8 degrees C to -8.4 degrees C (LT50). By contrast, the isolated protoplasts constitutively showed a consistent high level of free...

Arabidopsis CBF genes (CBF1-CBF3) encode transcription factors having a major role in cold acclimation, the adaptive process whereby certain plants increase their freezing tolerance in response to low non-freezing temperatures. Under these conditions, the CBF genes are induced and their corresponding proteins stimulate the expression of target genes configuring low-temperature transcriptome and...

Winter survival for many cold-blooded species involves freeze tolerance, the capacity to endure the freezing of a high percentage of total body water as extracellular ice. The wood frog (Rana sylvatica) is the primary model animal used for studies of vertebrate freeze tolerance and current studies in my lab are focused on the freeze-induced changes in gene expression that support freezing survi...

In spring, the lowest temperature during freezing that can be survived by wood frogs (Rana sylvatica) from southern Ohio is approximately -3 degrees C. We investigated whether the thermal limit of freeze tolerance in these frogs is regulated by tissue levels of glucose, a putative cryoprotectant that is distributed to tissues during freezing. Frogs receiving exogenous glucose injections prior t...

Ectothermic vertebrates have colonized regions that are seasonally or perpetually cold, and some species, particularly terrestrial hibernators, must cope with temperatures that fall substantially below 0°C. Survival of such excursions depends on either freeze avoidance through supercooling or freeze tolerance. Supercooling, a metastable state in which body fluids remain liquid below the equilib...

Subarctic populations of the wood frog Rana sylvatica survive freezing to temperatures at least 10–13°C below those of more southerly conspecifics. This profound freeze tolerance is due in part to an enhanced glucosic cryoprotectant system that requires rapid mobilization of glucose from hepatocytes during the early hours of freezing. To determine if glucose transporter 2 (GLUT2) in the liver c...

Several lipid-transfer proteins were reported to modulate the plant response to biotic stress; however, whether lipid-transfer proteins are also involved in abiotic stress remains unknown. This study characterized the function of a lipid-transfer protein, LTP3, during freezing and drought stress. LTP3 was expressed ubiquitously and the LTP3 protein was localized to the cytoplasm. A biochemical ...