title: Quantification of Giardia transcripts during in vitro excystation: interest for the estimation of cyst viability.
abstract: The aim of the present study was to evaluate the potential of transcript quantification as an indicator of Giardia cyst viability. The variations of beta-giardin, EF1A and ADHE mRNAs were quantified during excystation by real-time RT-PCR assays and compared with the percentages of viability estimated using propidium iodide staining and in vitro excystation. The first experiments were performed with purified G. duodenalis assemblage B cysts. When 55% of excysting protozoa were observed, the increase of the selected transcripts ranged from 0.40+/-0.13 to 0.97+/-0.11 log10 after 1h of incubation in excystation medium. Purified cysts were also stored at 4 degrees C for up to 56 days and analysed at several sampling times. Significant correlations were observed between the variations of the selected mRNAs and the percentages of viability estimated with staining and excystation methods. Among the three transcripts, beta-giardin appeared to be the most appropriate to study the viability of Giardia cysts concentrated from wastewater samples.
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Department of Environment and Agro-biotechnologies (EVA), 41 rue du Brill, L-4422 Belvaux, Luxembourg. isabelle.bertrand@pharma.uhp-nancy.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bertrand
authors.forename: Mélinda
authors.initials: M
authors.lastname: Maux
authors.forename: Karim
authors.initials: K
authors.lastname: Helmi
authors.forename: Lucien
authors.initials: L
authors.lastname: Hoffmann
authors.forename: Janine
authors.initials: J
authors.lastname: Schwartzbrod
authors.forename: Henry-Michel
authors.initials: HM
authors.lastname: Cauchie
mesh_terms: D000818:Animals; D003598:Cytoskeletal Proteins; D005872:Giardia / Q000235:genetics* / Q000502:physiology*; D015800:Protozoan Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D003598:Cytoskeletal Proteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; C038207:giardin protein, Giardia lamblia