原子氧自由基阴离子对大肠杆菌细胞作用的研究

研究了原子氧自由基阴离子(O-)对大肠杆菌的失活作用和形貌变化的影响.实验所用的O-自由基由新研制的O-发生器制备,其中Ca24Al28O64]4· 4O-(缩写为C12A7-O-)材料是O-发生器中发射O-的部分.实验结果表明,大肠杆菌的失活率随O-强度的变化而变化,在O-强度为1.5μA/cm2时,细胞的死亡率大大加强,作用120min后,细胞死亡率超过3个对数量级.通过场发射扫描电子显微镜观察发现O-对细胞结构具有破坏作用.通过丙二醛(MDA)的形成证实了O-诱导大肠杆菌发生脂质过氧化反应过程的存在,这可能是大肠杆菌死亡的潜在原因.当1.5μA/cm2的O-流通入到大肠杆菌悬浊液后,丙二醛浓度开始升高,15min后达到最高值1.2μmol/g,然后缓慢下降.结果显示,原子氧自由基阴离子能失活大肠杆菌,诱导脂质过氧化反应,这对发展一种新的净化微生物污染方法和研究微生物与原子氧自由基阴离子相互作用具有潜在的意义.

Effects of Atomic Oxygen Radical Anion on Escherichia coli Cells

The effects of atomic oxygen radical anion (O-) on the inactivation and morphological changes ofEscherichia coli (E. coli)on the surface of bio-indicator carrier were investigated. The O- flux was generated from a novel developed O- generator where the Oinactivation ofE. coli was sensitive to the O- intensity and the cell mortality was enhanced to more than 3-logarithm reduction with the exposure to 1.5 mA/cm2 O- flux for 120 min. Field emission scanning electron microscopy (FESEM) observations showed that O- flux destroyed cellular structures. Lipid peroxidation reaction induced by atomic oxygen radical anion for E. coli cells was also observed using product of malondialdehyde (MDA) as an index. The concentration of MDA increased to 1.2 μmol/g(dry weight) of cells when E. coli suspension (5.6×107 cfu/ml) was treated by the O- flux (1.5 μA/cm2) for 15 min. The findings revealed that the atomic oxygen radical anions, with strong oxidation power, was effective in inactivating E. coli and caused lipid peroxidation reaction at the first time,which would be potential useful to develop a novel approach for the microbial decontamination and for the study on the interactions between microorganisms and O-.