Ice Formation in Living Organisms

This chapter describes the consequences of cold exposure and ice formation on both the cellular, tissue and the organismal level in cold tolerant ectothermic organisms. This includes the direct implication of cold “per se” on various parameters such as pH, membrane fluidity and phase transitions, ionic gradients, metabolism, cold denaturation of proteins, ice nucleation, ice growth, freezing-induced cellular dehydration, the role of aquaporins and the mechanical stress caused by ice, while referring to the different aspects described in the previous chapter on ice in general. Defensive/preventive adaptations and mechanisms of the organisms are described as well, along with a description of freeze tolerance and freeze avoidance. The synthesis and mechanisms of action of low molecular weight cryoprotectants as well as their distribution are discussed. High molecular weight cryoprotectants are also described concluding with the introduction of the AFPs.