Makioka A, Kumagai M, Ohtomo H, Kobayashi S, Takeuchi T
Department of Tropical Medicine, Jikei University School of Medicine, Tokyo, Japan.
J Parasitol. 2000 Jun;86(3):607-10. doi: 10.1645/0022-3395(2000)086[0607:EODHOT]2.0.CO;2.
The effect of the dinitroaniline herbicides oryzalin and trifluralin on the growth of Entamoeba histolytica was examined. Oryzalin inhibited the growth of E. histolytica strain HM-1:IMSS. Trifluralin was less effective than oryzalin for this parasite. Entamoeba histolytica was more resistant to these dinitroanilines than other parasitic protozoa examined so far, including Leishmania spp., Trypanosoma brucei, Plasmodium falciparum, Toxoplasma gondii, and Cryptosporidium parvum. Colchicine, a potent microtubule inhibitor of animal cells, was much less effective for E. histolytica, even at very high concentrations. A reptilian parasite, Entamoeba invadens strain IP-1, examined for comparison, was more resistant to these dinitroanilines than E. histolytica. Accumulation of E. histolytica trophozoites in mitosis was observed after culture in 100 microM oryzalin. The inhibitory effect of oryzalin on the growth of E. histolytica trophozoites was abrogated by removal of the drug after exposure to 100 microM for 2 days. In parallel to the recovery of growth after removal of the drug, the percentage of trophozoites in mitosis was reduced to a normal level. The results indicate that treatment of trophozoites with oryzalin arrests mitosis and that its effect is reversible. Therefore, oryzalin is a useful tool for studies relating to the cell cycle of this parasite.
研究了二硝基苯胺类除草剂安磺灵和氟乐灵对溶组织内阿米巴生长的影响。安磺灵抑制了溶组织内阿米巴HM-1:IMSS株的生长。氟乐灵对这种寄生虫的效果不如安磺灵。与包括利什曼原虫属、布氏锥虫、恶性疟原虫、刚地弓形虫和微小隐孢子虫在内的目前所检测的其他寄生原生动物相比，溶组织内阿米巴对这些二硝基苯胺更具抗性。秋水仙碱是一种对动物细胞有效的微管抑制剂，即使在非常高的浓度下，对溶组织内阿米巴的效果也差得多。作为比较而检测的一种爬行动物寄生虫——侵袭内阿米巴IP-1株，比溶组织内阿米巴对这些二硝基苯胺更具抗性。在100微摩尔安磺灵中培养后，观察到溶组织内阿米巴滋养体在有丝分裂中积累。在暴露于100微摩尔2天后去除药物，安磺灵对溶组织内阿米巴滋养体生长的抑制作用被消除。与去除药物后生长恢复同时，处于有丝分裂的滋养体百分比降至正常水平。结果表明，用安磺灵处理滋养体会使有丝分裂停滞，且其作用是可逆的。因此，安磺灵是研究这种寄生虫细胞周期的有用工具。
