Ciliate cryptobiosis: a microbial strategy against environmental starvation

Abstract

This review outlines the main features of ciliate resting-cyst formation or encystment. It represents a strategy against several environmental stresses (such as starvation), which involves a highly gene-regulated cell differentiation process and originates a more resistant, differentiated form or resting cyst. This process is mainly characterized by drastic cytoplasmic dehydration that induces a general metabolic rate decrease, intense autophagic activity, the formation of a permeable cyst wall protecting the cell against the adverse environmental conditions, and a gene-silencing mechanism after opening the specific encystment genes.