Connell C, Rutter A, Hill B, Suller M, Lloyd D. Encystation of Acanthamoeba castellanii: Dye uptake for assessment by flow cytometry and confocal laser scanning microscopy.
J Appl Microbiol 2001;
90:706-12. [PMID:
11348429 DOI:
10.1046/j.1365-2672.2001.01296.x]
[Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS
To develop rapid means of distinguishing between cysts and trophozoites of the opportunistic pathogen, Acanthamoeba castellanii, the causative agent of keratitis.
METHODS AND RESULTS
Fluorescence of Congo Red, Calcoflor White was specific for the endocyst wall; trophozoites did not become fluorescent. The anionic oxonol dye, DiBAC4(3), did not penetrate the cytoplasmic membrane after short-term (<5 min) exposure, whereas cysts are permeable and become fluorescent. Confocal scanning laser microscopy confirmed these properties and large populations of organisms were analysed by flow cytometry.
CONCLUSION
These data provide a rapid alternative to traditional haemocytometer or plate counts for discrimination of trophozoites from cysts.
SIGNIFICANCE AND IMPACT OF THE STUDY
Rapid and precise determination of the growth cycle of a dangerous ocular pathogen.
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