Giardia intestinalis: expression of ubiquitin, glucosamine-6-phosphate and cyst wall protein genes during the encystment process

Abstract

We determined the relative expression of ubiquitin (ub), glucosamine-6-phosphate-isomerase (gn6pi) and cyst wall protein (cwp) genes during encystment of the Portland-1 and Portland-1R strains of Giardia intestinalis. Encystment was induced with bile for different time periods. The presence of encystment-specific vesicles (ESVs) and the relative expression of genes (log(10)ΔRn) were determined by transmission electron microscopy and real-time PCR, respectively. Our results demonstrated the gene expression and the presence of ESVs after 6h of encystment. Values of cwp2 gene expression increased by 591-fold in strain Portland-1 and 78.2-fold in strain Portland-1R at this time point compared to values at 0h, after which values gradually decreased until reaching basal values between 8 and 18h after the encystment started. Expression of gn6pi was 43.5- and 46.3-fold higher than basal values, in Portland-1 and Portland-1R, respectively. Ub gene expression was 82.25-fold higher than its basal levels at 4h, after which expression decreased gradually until reaching basal values after 16h.

Conclusions: This work showed the relationship between the presence of ESVs and encystment gene expression at 6h, and resistance to albendazole does not inhibit the encystment process. The results revealed important knowledge with implications in the control of parasite dissemination for preventing parasite transmission.