Resting Cyst Formation as a Strategy for Environmental Adaptation in Colpodid Ciliates.

Abstract

Resting cyst formation is a strategic aspect of the life cycle of some eukaryotes such as protists, and particularly ciliates, that enables adaptation to unfavorable environmental conditions. The formation of resting cysts involves large scale morphological and physiological changes that provide tolerance of extreme environmental stresses. The resting cyst shows suppression of normal features of life such as eating, moving, proliferation, and even mitochondrial metabolic activity, and appears lifeless. This review discusses resting cyst formation in the ciliates Colpoda as a representative model of cyst-forming organisms, and focusses on morphogenesis, molecular events, tolerances, and metabolic activities in resting cysts.