Rengpien S, Bailey G B
J Parasitol. 1975 Feb;61(1):24-30.
Nutritional and culturing requirements for efficient axenic encystation of Entamoeba invadens have been studied. A simple and reliable axenic encystation medium has been developed. It contains 0.5% tryptic digest of casein, 0.5% yeast extract, and 5% dialyzed serum in 5 mM potassium phosphate, pH 7.0. Mass encystation (avg 70%) occurred within 30 hr when axenically growing trophozoites of E. invadens IP-l were transferred to this medium before they entered stationary growth phase. Mass encystation of E. invadens PZ occurred similarly, but less reproducibly. Two E. histolytica strains did not encyst. Experiments established that differentiation did not depend upon changes in the external environment after amebase were transferred to encystation medium and, therefore, was initiated by the shift from growth to encystation medium.
对侵袭内阿米巴高效无菌包囊化的营养和培养要求进行了研究。已开发出一种简单可靠的无菌包囊化培养基。它在5 mM磷酸钾（pH 7.0）中含有0.5%酪蛋白胰蛋白酶消化物、0.5%酵母提取物和5%透析血清。当侵袭内阿米巴IP-1的无菌生长滋养体在进入稳定生长期之前转移到这种培养基中时，在30小时内发生了大量包囊化（平均70%）。侵袭内阿米巴PZ的大量包囊化情况类似，但重复性较差。两种溶组织内阿米巴菌株未发生包囊化。实验表明，分化并不取决于变形虫转移到包囊化培养基后外部环境的变化，因此，是由从生长培养基转移到包囊化培养基引发的。
