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Updated: Mar 1, 2026

Monitoring the Effect of Osmotic Stress on Secretory Vesicles and Exocytosis
Published on: February 19, 2018
Protozoa inhibition by different salts: Osmotic stress or ionic stress?
Changhao Li1, Jingya Li1,2, Christopher Q Lan2
1Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur Private, Ottawa, ON, K1N 6N5, Canada.
Abstract:
Cell density and morphology changes were tested to examine the effects of salts including NaHCO3 , NaCl, KHCO3 , and KCl at 160 mM on protozoa. It was demonstrated that ionic stress rather than osmotic stress led to protozoa cell death and NaHCO3 was shown to be the most effective inhibitor. Deformation of cells and cell shrinkage were observed when protozoan cells were exposed to polyethylene glycol (PEG) or any of the salts. However, while PEG treated cells could fully recover in both number and size, only a small portion of the salt-treated cells survive and cell size was 36-58% smaller than the regular. The disappearance of salt-treated protozoa cells was hypothetically attributed to disruption of the cytoplasmic membrane of these cells. It is further hypothesized that the PEG-treated protozoan cells carried out regulatory volume increase (RVI) after the osmotic shock but the RVI of salt-treated protozoa was hurdled to varied extents. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1418-1424, 2017.
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