pH及氧气对白念珠菌菌丝形成的影响

目的探讨pH值和氧气对白念珠菌菌丝形成的影响。方法通过调节Muller—Hinton液体培养基的pH值和去除培养基中的氧气来观察白念珠菌的生长曲线、倍增时间和菌丝形成率的变化。结果在无氧气的液体培养基中，白念珠菌生长缓慢，不能产生菌丝结构，只有酵母细胞形成。生长曲线的延缓期内各组没有明显差异，而在生长的对数期pH3和pH4的条件下念珠菌生长速度明显慢于pH5、pH6、pH7、pH8和pH9。菌丝形成率在pH3、pH4和pH5条件下〈20％，而在pH6、pH7、pH8和pH9条件下可高达70％。结论厌氧条件抑制白念珠菌的菌丝形成，只形成酵母细胞。白念珠菌在pH3—9的范围内均能生长，偏酸性环境有利于白念珠菌酵母形成，偏碱性的环境有助于菌丝的形成。

Effect of pH and oxygen on the filamentaion of Candida albicans

Objective To investigate the effects of pH and oxygen on the filamentation of Candida albicans. Methods Candida albicans was incubated in Muller-Hinton broth at 37℃ for induction of filamentation in vitro . Growth curve, doubling time and percent of filamentation of Candida albicans were observed under aerobic, anaerobic condition and different pH value at intervals. Resuits Candida albicans grew slowly without hyphae but yeast under anaerobic condition. No difference of growth rate was found in lag phase of Candida albicans under different pH value conditions. Growth rate in log phase was slower under pH3, pH4 than pHS, pH6, pH7, pH8 and pH9. Filamentation percent of Candida albicans was less than 20% under pH3, pH4 and pHS. Filamentation percent of Candida albicans was up to 70% under pH6, pH7, pH8 and pH9. Conclusions Hyphae was completely inhibited and only yeast form could be detected under anaerobic condition. Candida albicans can thrive at a wide range of extraeellular pH value from 3 to 9. Acidic conditions favor yeast growth, while alkaline conditions favor hyphal growth.