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Morphological Study of the Encystment and Excystment of Vermamoeba vermiformis Revealed Original Traits
Author(s) -
Fouque Emilie,
Yefimova Marina,
Trouilhé MarieCécile,
Quellard Nathalie,
Fernandez Béatrice,
Rodier MarieHélène,
Thomas Vincent,
Humeau Philippe,
Héchard Yann
Publication year - 2014
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12185
Subject(s) - acanthamoeba , biology , protozoa , cryptobiosis , microbiology and biotechnology , cytoplasm , cyst , phagosome , amoeba (genus) , organelle , ecology , pathology , medicine , phagocytosis , desiccation
Free‐living amoebae are ubiquitous protozoa commonly found in water. Among them, Acanthamoeba and Vermamoeba (formerly Hartmannella ) are the most represented genera. In case of stress, such as nutrient deprivation or osmotic stress, these amoebae initiate a differentiation process, named encystment. It leads to the cyst form, which is a resistant form enabling amoebae to survive in harsh conditions and resist disinfection treatments. Encystment has been thoroughly described in Acanthamoeba but poorly in Vermamoeba . Our study was aimed to follow the encystment/excystment processes by microscopic observations. We show that encystment is quite rapid, as mature cysts were obtained in 9 h, and that cyst wall is composed of two layers. A video shows that a locomotive form is likely involved in clustering cysts together during encystment. As for Acanthamoeba , autophagy is likely active during this process. Specific vesicles, possibly involved in ribophagy, were observed within the cytoplasm. Remarkably, mitochondria rearranged around the nucleus within the cyst, suggesting high needs in energy. Unlike Acanthamoeba and Naegleria , no ostioles were observed in the cyst wall suggesting that excystment is original. During excystment, large vesicles, likely filled with hydrolases, were found in close proximity to cyst wall and digest it. Trophozoite moves inside its cyst wall before exiting during excystment. In conclusion, Vermamoeba encystment/excystment displays original trends as compare to Acanthamoeba .