pH 值对白色念珠菌形态和侵袭力影响的研究

摘要

Objective To investigate the multiplication and morphological switch as well as the difference of invasiveness of C.albicans under different pH.Methods Prepare yeast peptone dextrose (YPD)liquid medium with 5 different pH and inoculate the 5 groups medium with the same amount of standard C.albicans strain(1 00 μl organism suspension with the concentration of 3 ×1 05 /ml).Culture for 48 h under 37 ℃ in constant temperature incubators,then count the C.albicans yeast phase and hyphal state respectively.Analyze the amount differences of C.Albicans yeast phase and hyphal state among the groups.Inoculate the prepared Caco-2 cell with 1 00 μl organism suspension of C.albicans which was cul-tured before from the 5 groups.Caco-2 cell liquid medium from the 5 groups was collected every one hour after C.albicans was inoculated,then measure lactate dehydrogenase(LDH)of the collected Caco-2 cell liquid medium.The measure terminated when LDH is more than 1 60 U /L,record the time it cost and ana-lyze the differences among the groups.The compound of Caco-2 cell and fungi is cultured for 24 hours in total,then count the epibiotic adherence Caco-2 cells and analyze the differences among the groups. Results In pH =7.0 group,the amount of C.albicans yeast phase was(5.47 ±0.51 )×1 08 /ml,and the hyphal state was(2.41 ±0.42)×1 08 /ml,both were more than those in others groups with statistical sig-nificance(P <0.05).In pH =9.0 group,when the LDH level reached 1 60 U /L,it cost(22.1 0 ±2.00) hours,it was more than others groups,with a statistically significant difference(P <0.05).In pH =9.0 group,the amount of epibiotic adherence Caco-2 cells was(78.1 0 ±8.54)×1 06 /ml,which was higher than other experimental groups(P <0.05).Conclusion pH plays an important role on the morphological switch and invasiveness of C.albicans.Neutral microenvironment is favourable to C.albicans growth.It also promotes the morphological switch from yeast phase to hyphal state.In alkaline microenvironment,the destructiveness of C.albicans will be inhibited.%目的：研究 pH 值对白色念珠菌增殖和形态的影响，并探讨不同 pH 值条件下培养的白色念珠菌破坏力的差异。方法制备5组不同 pH 值的酵母浸出粉胨葡萄糖（YPD）液体培养基。取100μl 浓度为3×105个／ml 的白色念珠菌悬液，分别接种于各组培养基，恒温培养48 h 后，对各组的出芽酵母相和菌丝相的白色念珠菌计数，比较各组间的差异。取各组培养所得100μl 白色念珠菌菌悬液，接种于制备好的 Caco-2细胞培养瓶中，每隔1 h 测定细胞培养液乳酸脱氢酶（LDH）的水平，设定 LDH 浓度＞160 U ／L 为目标，分别记录各组所需时间，比较各组间差异。共同培养24 h 后，对残留的贴壁 Caco-2细胞进行计数，比较各组间差异。结果pH ＝7．0组白色念珠菌出芽酵母相计数为（5．47±0．51）×108／ml，菌丝相计数为（2．41±0．42）×108／ml，均明显高于其余各组，差异有统计学意义（P ＜0．05）。pH ＝9．0组 LDH 浓度达到160 U ／L 水平所需时间为（22．10±2．00）h，明显长于其余各实验组，差异有统计学意义（P ＜0．05）。pH ＝9．0组残留的贴壁Caco-2细胞计数为（78．10±8．54）×106／ml，高于其余各组，差异有统计学意义（P ＜0．05）。结论pH 值对白色念珠菌的形态和破坏力有显著影响，中性环境更有利于白色念珠菌的生长及促使酵母相向菌丝相转化，碱性环境下白色念珠菌的破坏力下降。