Fig. 1.

Adaptations to stress in Artemia cysts. When in diapause and quiescence, Artemia cysts may experience stressors (blue boxes) and several cyst-specific characteristics/mechanisms have evolved to offset these adverse environmental and physiological conditions. Artemia cysts are surrounded by a rigid, semi-permeable shell, a morphological adaptation that resists UV radiation and is the first line of defense for the enclosed embryos. The disaccharide trehalose is synthesized by diapause-destined embryos and, with LEA proteins, is thought to be especially effective in protecting cysts against desiccation. The molecular chaperones p26 and artemin prevent irreversible protein denaturation during stress, acting as a first-line, molecular-level defense. These adaptations function in concert, endowing Artemia cysts with a degree of stress tolerance seldom seen in any life history stage of any other animal