The effect of drugs on the cell cycle of Giardia intestinalis.
Flow cytometric analysis of the binucleated protozoan parasite Giardia intestinalis gave DNA histograms with a broad G1 peak and a definable G2 + M peak with twice the DNA content of G1. Twenty-four hour treatment with metronidazole arrested cell cycle progression of susceptible trophozoites in the G2 + M phase, but had no effect, even at toxic doses, on the DNA histogram of a line selected for resistance to metronidazole. Furazolidone was inhibitory to both stocks, causing an arrest in the S and G2 + M phases. Inhibitors of the mammalian cell cycle were also tested. Hydroxyurea, which blocks mammalian cells in G1/S, and razoxane, which blocks in G2 + M, arrested trophozoites in the G2 + M phase whereas colchicine and gamma-irradiation had little or no effect on the cell cycle of G. intestinalis. These results suggest that the cell cycle of G. intestinalis may be controlled in a different manner from mammalian cells.
Hoyne
G F
GF
Queensland Institute of Medical Research, Herston, Brisbane, Queensland, Australia.
Boreham
P F
PF
Parsons
P G
PG
Ward
C
C
Biggs
B
B
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D003078:Colchicine / Q000494:pharmacology; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D005664:Furazolidone / Q000494:pharmacology*; D005872:Giardia / Q000187:drug effects*; D006918:Hydroxyurea / Q000494:pharmacology; D008795:Metronidazole / Q000494:pharmacology*; D011929:Razoxane / Q000494:pharmacology
D008795:Metronidazole; D011929:Razoxane; D005664:Furazolidone; D004247:DNA; D003078:Colchicine; D006918:Hydroxyurea