Advertisement

Parasitology Research

, Volume 86, Issue 8, pp 625–629 | Cite as

Effect of the antitubulin drug oryzalin on the encystation of Entamoeba invadens

  • Asao Makioka
  • Masahiro Kumagai
  • Hiroshi Ohtomo
  • Seiki Kobayashi
  • Tsutomu Takeuchi
ORIGINAL PAPER

Abstract

We have recently demonstrated that the antimicrotubule drug oryzalin inhibits the growth of Entamoeba invadens as well as E. histolytica, the former being more resistant to the drug than the latter, and that effective doses of oryzalin are higher for Entamoeba than for the other parasitic protozoa examined thus far. The aim of the present study was to examine the effect of oryzalin on the encystation of E. invadens using an axenic encystation system in vitro. Oryzalin inhibited the encystation of E. invadens strain IP-1 in a dose-dependent manner. The addition of oryzalin after the induction of encystation was also inhibitory for encystation and cyst maturation. Trophozoites incubated for 1 day in encystation medium with oryzalin did not encyst after removal of the drug. Although trophozoites grown in the presence of 300 μM oryzalin for 2 days did not encyst after their transfer to encystation medium containing the same concentration of drug, a number of trophozoites survived for at least 3 days. In contrast, trophozoites grown in the absence of oryzalin neither survived nor encysted after their transfer to encystation medium supplemented with the drug, which suggests that pretreatment of trophozoites with oryzalin contributes to their continued survival as trophozoites, i.e., without their transforming into cysts, in encystation medium. Trophozoites grown with oryzalin did encyst after their transfer to encystation medium without the drug. Accumulation of trophozoites in the mitotic phase was observed after culture with oryzalin. When cysts prepared at day 1 of encystation, most of which were mononucleate, were reincubated in the presence of oryzalin for an additional 2 days, inhibition of their maturation was observed. Thus, oryzalin is a potent mitotic-phase inhibitor of E. invadens and may become a useful tool for studies on the relationship between the cell cycle and encystation of this parasite.

Keywords

Cell Cycle Effective Dose Parasitic Protozoan Continue Survival Oryzalin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Asao Makioka
    • 1
  • Masahiro Kumagai
    • 1
  • Hiroshi Ohtomo
    • 1
  • Seiki Kobayashi
    • 2
  • Tsutomu Takeuchi
    • 2
  1. 1.Department of Tropical Medicine, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan e-mail: makioka@jikei.ac.jp Tel.: +81-3-34331111 ext. 2286 Fax: +81-3-34314459JP
  2. 2.Department of Tropical Medicine and Parasitology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, JapanJP

Personalised recommendations