中文摘要：

目的观察巨噬细胞过氧化物酶体在鼠伤寒沙门菌感染中的作用。方法将感染及未感染鼠伤寒沙门菌的鼠巨噬细胞RAW264.7以氮气压迫法裂解,逐级离心,用制备的TassC多抗磁珠纯化得到粗提液,用Western blot法鉴定TassC多抗磁珠与细胞结合物的性质;用pDs Red2-Perxi质粒转染RAW264.7细胞以标记细胞中的过氧化物酶体,用三维荧光显微镜观察感染细胞中过氧化物酶体（红色）与表达绿色荧光蛋白的鼠伤寒沙门菌突变株的相互作用。结果Western blot分析显示TassC多抗磁珠可以结合细胞内的TassC,并与细胞内的过氧化物酶体结合,也可以与感染细胞中的iNOS结合,而未感染样本中未检测到iNOS。磁珠洗脱物中未检测到溶酶体标志物LAMP1,也未检测到受染菌标志物;免疫荧光显示感染的巨噬细胞中过氧化物酶体聚集在鼠伤寒沙门菌突变株SCV周围,甚至发生重叠,随感染时间延长（1h或24h）,过氧化物酶体数量增加（1.2倍或1.3倍）,而胞内菌数量下降。结论TassC可能定位于过氧化物酶体而不是溶酶体;感染鼠伤寒沙门菌的巨噬细胞中iNOS可能与过氧化物酶体结合而参与杀灭微生物的作用。

英文摘要：

Objective To understand the role of peroxisomes on the intracellular survival of Salmonella typhimurium in macrophages. Methods Vesicles from infected or uninfected RAW264.7 macrophage-like cells were isolated by stepwise centrifugation after cells were broken by nitrogen cavitation and purified with magnetic beads containing polyclonal antibodies to TassC （Target for Salmonella secreted protein SpiC）. Western-blot was used to detect the characters of the binding vesicles. Three-dimensional （xyz） fluorescence microscopy was used to determine the recruitment of peroxisomes tagged with pDsRed2-Perxi to the SCV after infection of RAW264.7 cells with Salmonella typhimurium mutant strains spiC：kan producing GFP. Volocity software was employed for image analysis. Overlap of individual fluorescence pixels from separated channels for each optical plane was determined with the Volocity 4.1 colocalization module. Results It was shown by western-blot that the anti-TassC magnetic beads could bind TassC and peroxisomal marker catalase in infected or uninfected RAW264.7 cells. Inducible nitric oxide synthase （iNOS） could be detected in infected samples, but couldn’t in uninfected samples. Lysosome associated membrane protein （LAMP1）, one of the lysosome markers, and a bacterium marker RecA could not be detected from the elution of anti-TassC magnetic beads. It was determined by a fluorescence microscopy that the recruitment or overlapping of peroxisomes tagged with pDsRed2-Perxi to the Salmonella-containing vacuoles after infection of RAW264.7 cells with Salmonella mutant strains producing GFP. Calculation by Volocity 4.1 showed that peroxisome abundance increased by 1.2- or 1.3-fold, respectively, at 1h and 24h time point of infection in the infected macrophages than in uninfected cells while the bacteria abundance decreased with the infection time. Conclusion It is suggested that TassC is localized with peroxisomes, but not with lysosomes. Inducible nitric oxide synthase might be localized to peroxisomes