Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Models for Excystation.
Author Meyer, E. A. ; Schaefer, F. W. ;
CORP Author Oregon Health Sciences Univ., Portland. ;Health Effects Research Lab., Cincinnati, OH.
Year Published 1984
Report Number EPA/600/D-84/280;
Stock Number PB85-128189
Additional Subjects Cysts ; Models ; Excystation ; Giardia lamblia ; Giardia muris
Library Call Number Additional Info Location Last
NTIS  PB85-128189 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 06/23/1988
Collation 30p
Two methods are described for inducing Giardia lamblia to excyst. Both at times can be shown to yield trophozoites, although the success rate varies widely depending on the investigator and the cyst source. The excystation procedure for Giardia muris is much more satisfactory; however, results using it as a substitute or model for Giardia lamblia should be interpreted with great caution. It is suggested that all the factors involved in excystation have not been identified as yet. Several areas that appear to need rapid attention are the composition of the cyst wall, definition of factors in the incubation media that promote excystation, and determination of the presence or absence of endogenous enzymes associated with Giardia trophozoites. Also a study of the relationship of excystation to infectivity is needed badly. Presently excystation is only a measure of viability. The investigator interested in studying Giardia excystation should use these methods as a starting point for delineating the process even further.