Ujimine Shiori, Tone Shigenobu, Saito Mineki, Yamada Sakuo
Department of Health Science, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama, 701-0193, Japan.
Graduate School of Science and Engineering, Tokyo Denki University, Hatoyama, Saitama, 350-0394, Japan.
Med Mol Morphol. 2017 Sep;50(3):178-184. doi: 10.1007/s00795-017-0159-6. Epub 2017 May 17.
Sodium hypochlorite (NaOCl) is commonly used as a disinfectant; however, its bactericidal mechanism has not yet been clarified. In the present study, the bactericidal mechanism of NaOCl was examined using microscopy and gel electrophoresis techniques with Staphylococcus aureus strain 209P. S. aureus cells treated with 500 and 1000 ppm NaOCl for 5 and 15 min were observed by SEM and TEM. SEM images of the bacterial cells treated with NaOCl showed an irregular surface, with cells being partially invaginated. TEM images of the bacterial cells showed cytoplasmic alterations, accompanied by a partially irregular cellular surface. Under a fluorescence microscope, we clearly observed fluorescence quenching in the 1000 ppm NaOCl-treated cells. Based on these observations, which indicated that NaOCl damaged chromosomal DNA, we next extracted chromosomal DNA from bacterial cells treated with NaOCl and performed agarose gel electrophoresis. Chromosomal DNA was absent in the DNA sample from the bacterial cells treated with 500 ppm NaOCl. From these biochemical results, it was strongly suggested that NaOCl degrades the chromosomal DNA of S. aureus. We consider that the morphological changes in the cytoplasm induced by NaOCl may be related to NaOCl-induced degradation of S. aureus chromosomal DNA.
次氯酸钠（NaOCl）常用作消毒剂；然而，其杀菌机制尚未阐明。在本研究中，使用显微镜和凝胶电泳技术，以金黄色葡萄球菌209P菌株研究了NaOCl的杀菌机制。用扫描电子显微镜（SEM）和透射电子显微镜（TEM）观察了经500和1000 ppm NaOCl处理5分钟和15分钟的金黄色葡萄球菌细胞。经NaOCl处理的细菌细胞的SEM图像显示表面不规则，细胞部分内陷。细菌细胞的TEM图像显示细胞质改变，伴有部分不规则的细胞表面。在荧光显微镜下，我们清楚地观察到经1000 ppm NaOCl处理的细胞中的荧光猝灭。基于这些表明NaOCl破坏染色体DNA的观察结果，我们接下来从经NaOCl处理的细菌细胞中提取染色体DNA并进行琼脂糖凝胶电泳。在经500 ppm NaOCl处理的细菌细胞的DNA样品中不存在染色体DNA。从这些生化结果强烈表明，NaOCl降解金黄色葡萄球菌的染色体DNA。我们认为，NaOCl诱导的细胞质形态变化可能与NaOCl诱导的金黄色葡萄球菌染色体DNA降解有关。
