Molecular Events During Resting Cyst Formation in Unicellular Eukaryote Colpoda

Abstract

The morphogenetic changes in encystment-induced Colpoda cells are described as follows:2~3 h after Encystment Induction: The cells stop swimming and begin to aggregate by an excretion of sticky mucus. The cells then round up, and then small sticky globules showing a fibrous or crystal-like fine structure [9] called lipidosomes [10] are extruded to be trapped by the mucus layer, followed by the formation of an ectocyst layer (a rigid single-cyst wall layer) [9]. In this stage, the cellular structures characterizing vegetative cells such as cilia begin to disintegrate and mitochondrial activity is arrested [11].3~5 h after Encystment Induction: At 3~5 h after encystment induction, the first-synthesized endocyst layer is formed by the excretion and gelation of an endocyst-precursor substance between