Fig. 2 in Antifreeze Water-Rich Dormant Cysts of the Terrestrial Ciliate Colpoda cucullus Nag-1 at -65 ℃: Possible Involvement of Ultra-Antifreeze Polysaccharides

Fig. 2. Detection of polysaccharides in C. cucullus Nag-1 encysting cells. (A) A PAS-stained vegetative cell (a), a 3-h-old immature cyst (b), a 1-day-old immature cyst (c), an almost mature cyst (5 days old) (d) and a toluidine-blue stained thick section of a 1-week-old mature cyst (f). (e) PAS-stained 1-week-old mature cysts at 10 min after onset of excystment induction. cw: cyst wall, ec/en: an ectocyst layer lined with endocyst layers, ma: macronucleus, m: plasma membrane, elb: electron-lucent body (probably stored carbohydrate granules). (B) Tol- erance of excystment-induced cells (1-week-old cysts) to a temperature of −65℃. Excystment was induced for 10 min, and then the cells were cooled at −65℃ for 24 h and then thawed at room temperature. The excystment rate (%) was measured at 24 h after thawing, and was expressed as a percentage of the randomly chosen total number of cells (50 cells). Columns and attached bars correspond to the means of 6 measurements and the standard errors (SE), respectively. In each set of experiment (i.e., the cooling group and control group experiments), the same lot of samples was used. There was significant difference between the columns (p <0.01, Mann-Whitney test).