结肠小袋纤毛虫滋养体体外成囊条件的筛选和优化

目的 筛选和优化结肠小袋纤毛虫滋养体体外形成包囊的条件。方法 设定不同动物粪便、孵育液、pH值、Ca²⁺浓度、温度、静置和振荡培养等不同条件,孵育24 h观察其成囊情况。另外,用体外形成的包囊接种给仔猪,验证其感染性。结果 滋养体在新鲜的正常猪粪便和鸡粪便中,于37 ℃、28 ℃、15 ℃~20 ℃和-11 ℃~-2 ℃环境下,均没观察到包囊形成;在不含小牛血清和淀粉的蒸馏水、生理盐水、PBS溶液以及DMEM培养基中孵育,镜检发现在生理盐水(pH6.5)和PBS中存在大量滋养体和少量早期包囊出现;在pH值3~5之间的生理盐水中包囊的形成的数量明显增加,28 ℃环境下平均成囊率达到38.9%,相同pH值范围的蒸馏水却没发现包囊和滋养体。Ca²⁺浓度、温度、振荡和静置培养等因素对其体外成囊效果均没有明显影响。两头仔猪接种包囊后第4 d,均在粪便中检出该虫滋养体。结论 在15 ℃~28 ℃,pH值3~5的不含小牛血清和淀粉的生理盐水中是结肠小袋纤毛虫体外成囊的适宜条件。

Screening and optimization of encystation conditions of Balantioides coli trophozoite in vitro

In order to screen and optimize the encystation conditions of Balantioides coli trophozoites in vitro, different conditions including animal feces, incubation solutions, pH values, Ca²⁺ concentration, temperature, static and shaking culture were assayed, and the encystation of B. coli was observed after incubating 24 hours. In addition, piglets were inoculated with formed cysts in vitro to verify their infectivity. The trophozoites were added to fresh normal pig and chicken feces at 37 ℃, 28 ℃,15 ℃~20 ℃ and -11 ℃~-2 ℃, respectively. Results showed that there were no cysts observed in each group. When incubating in distilled water, 0.9% saline solution, PBS solution, DMEM medium without calf serum and starch, the presence of numerous trophozoites and few early stage cysts in saline solution (pH 6.5) and PBS were found by microscopic examination. The amount of formed cysts incubated in pH 3~5 saline solution was significantly increased, with the average encystation rate of 38.9% at 28 ℃. However, no cysts and trophozoites were found in the distilled water with the same pH range. Ca²⁺ concentration, temperature, shaking and static culture have no significant effect on the encystation of B. coli trophozoite in vitro. Subsequently, trophozoites of B.coli were detected in the feces of two piglets on the 4th day after inoculating cysts. In conclusion, the saline solution of pH 3~5 without calf serum and starch is a suitable condition for the formation of cysts in vitro at 15 ℃~28 ℃.