有氧胁迫幽门螺杆菌球形变异的实验研究

Study on coccoid transformation of Helicobacter pylori under oxidative stress

目的对有氧胁迫下幽门螺杆菌(Hp)的球形变异特征进行研究。方法采用细菌学、酶学、遗传学、动物实验等方法对有氧胁迫作用下形成的Hp球形体进行实验研究。结果随着有氧胁迫时间的延长,Hp螺旋体逐渐转化为球形体,代谢及酶活性逐渐下降并趋于稳定,与Hp定居相关的毒力基因表达有所减弱,但SodB和Kat在基因表达和酶活检测中均保持较高水平;部分Hp球形体可在小鼠体内回复定植。结论有氧胁迫下形成的Hp球形体代谢活性及毒力均有所减弱,但部分球形体仍具有活性。SodB和Kat可能在Hp活性氧代谢中发挥着重要作用。

Objective To study the character of transformation of H. pylori into coecoid form under oxidative stress, and the changes in the biological charasteristics after transformation. Methods The coccoid form of H. pylori was studied with bacteriological, enymological, and genetical methods to identify its differences from the original form. Animal experiment was conducted to determine its implantation capacity. Results Morphological transformation from spiral to coccoid form occurred with the prolongation of culture under oxygen stress. The metabolic activity was reduced gradually, finally maintained at a lower level. The activities of urease, alkaline phosphatase and acid phosphatase were decreased markedly. The mRNA levels of main virulence factors were declined. Both mRNA and activities of enzyme of Sod B and Kat retained high levels. A part of the coccoid forms showed reversion to helical form, and colonization in mice stomach could be found after being inoculated to mice. Conclusions The metabolism and virulence of H. pylori were all lowered under oxidative stress, but a part of the coccoid form may be viable. Sod B and Kat may play an important role in the oxygen metabolism of H. pylori.