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目的研究模拟微重力对肺炎克雷伯菌(KPN)生长、形态、蛋白表达以及4种毒力基因表达的影响。方法实验分为微重力组和对照组,采用回转器模拟微重力模型处理微重力组菌株,检测KPN微重力下的生长情况,电镜观察细菌形态,表面增强激光解吸电离飞行时间质谱技术(SELDI-TOF-MS)检测蛋白质表达及采用实时(real-time,RT)PCR检测ureA、wabG、uge、fimH 4种毒力基因的表达。结果微重力组与对照组相比,KPN的生长加快,最终菌量增加;扫描电镜见部分菌体形态发生变化,细长的菌体增多,透射电镜见细胞质内颗粒状物质增多;质谱分析结果有18个蛋白峰表达发生变化,表达上调和下调各9个,经蛋白库共检索出21个与其相对分子质量(Mr)相近蛋白,其中13个功能已知的蛋白与细菌的生命活动密切相关;RT-PCR结果表明,4种毒力基因表达均下调。结论微重力使KPN生长加快、繁殖能力增强,菌体形态、蛋白表达以及4种毒力基因表达均发生变化,微重力使KPN的生物学特性发生改变。
Objective To study the effects of simulated microgravity on the growth, morphology, protein expression and four virulence genes of Klebsiella pneumoniae (KPN). Methods The experiments were divided into two groups: microgravity group and control group. Gyrus microgravity model was used to treat the microgravity group. The growth of microgravity group was detected by KPN microgravity. The morphological changes of bacteria were observed by electron microscope. SELDI- TOF-MS) were used to detect the protein expression and the expression of four virulence genes of ureA, wabG, uge and fimH were detected by real-time PCR. Results Compared with the control group, the growth of KPN was accelerated in the microgravity group and the final bacterial count was increased. The morphological changes of some bacteria were observed by SEM, the number of elongated bacteria increased and the amount of granular material in cytoplasm increased by transmission electron microscopy. The results of mass spectrometry There were 18 protein peaks whose expression was up-regulated and 9 down-regulated. A total of 21 proteins with relative molecular mass (Mr) were found by protein library. Among them, 13 proteins with known functions were closely related to the life activities of bacteria The results of RT-PCR showed that the four virulence genes were down-regulated. Conclusion Microgravity accelerates the growth of KPN, enhances the reproductive ability, and changes the morphology, protein expression and expression of four virulence genes. Microbogravity changes the biological characteristics of KPN.