Morphological Study of the Encystment and Excystment of Vermamoeba vermiformis Revealed Original Traits
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....
Saved in:
Published in | The Journal of eukaryotic microbiology Vol. 62; no. 3; pp. 327 - 337 |
---|---|
Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Society of Protozoologists
01.05.2015
Blackwell Publishing Ltd Wiley |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | 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. |
---|---|
Bibliography: | http://dx.doi.org/10.1111/jeu.12185 ArticleID:JEU12185 istex:0E9D3B47D81AAB6E7D8F8ACD598212E8F500ACD3 ark:/67375/WNG-W17RH456-S Movie S1. Encystment of Vermamoeba vermiformis ATCC 50237 (duration: 10 h): encystment is synchronous and fast, it takes about 9 h. After immobilization, cells become spherical and often form clusters.Movie S2. Encystment of Vermamoeba vermiformis ATCC 50237, a zoom (duration: 9 h).Movie S3. Clustering of cysts during encystment of Vermamoeba vermiformis ATCC 50237 (duration: 9 h): several cells remain motile and appear to be involved in clusters formation.Movie S4. Excystment of Vermamoeba vermiformis ATCC 50237 (duration: 9 h): trophozoites move inside the cysts; trophozoites generate one or several cytoplasmic projections protruding the cyst wall; then trophozoites exit from the cyst wall.Movie S5. Excystment of Vermamoeba vermiformis ATCC 50237, a zoom (duration: 7 h). ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1066-5234 1550-7408 |
DOI: | 10.1111/jeu.12185 |