Yang Fan, Jiang Qun, Xie Weiling, Zhang Ying
School of Resources & Environment, Northeast Agricultural University, Harbin 150030, China; College of Science, Northeast Agricultural University, Harbin 150030, China.
School of Resources & Environment, Northeast Agricultural University, Harbin 150030, China.
Chemosphere. 2017 Oct;185:162-170. doi: 10.1016/j.chemosphere.2017.07.010. Epub 2017 Jul 3.
The effect of multi-walled carbon nanotubes (MWNTs) with different diameters on the destruction degree toward cellular membranes of bacterial has been explored by investigating the viability of bacteria and the change of composition and surface properties in cellular membranes with the exposure of MWNTs. The atrazine degrading bacteria Acinetobacter lwoffii DNS32 (DNS32) is chosen as the model species and Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) are selected as the comparison specie. Bacterial viability testing shows that MWNTs with smaller diameters generally display stronger toxicity to bacteria and also influenced by many factors including the electrostatic repulsion between MWNTs and bacteria and bacteria types. Interestingly, bacteria can self-regulate as an adaptive response to the toxicity of MWNTs, notably, DNS32 strain presents the adaptive responses when cultivated with MWNT through modification of fatty acids in cell membranes, but does not exhibit similar responses when exposed to MWNT. This result may be related to the interference from MWNT, which exceeds the cellular ability to self-repair. Transmission electron microscopy (TEM) images and flow cytometric analysis of bacteria exposed to MWNTs reveal that the destruction of cell membrane in the DNS32 strain is more serious than that in the B. subtilis, indicating that electrostatic repulsion between the material and bacteria leading to the decrease of direct contact may be the primary factor that reduces the impacts from MWNTs.
通过研究细菌的活力以及随着多壁碳纳米管（MWNTs）的暴露细胞膜组成和表面性质的变化，探讨了不同直径的多壁碳纳米管对细菌细胞膜破坏程度的影响。选择阿特拉津降解菌鲁氏不动杆菌DNS32（DNS32）作为模型菌株，并选择大肠杆菌（E. coli）和枯草芽孢杆菌（B. subtilis）作为对照菌株。细菌活力测试表明，直径较小的多壁碳纳米管通常对细菌表现出更强的毒性，并且还受到多种因素的影响，包括多壁碳纳米管与细菌之间的静电排斥以及细菌类型。有趣的是，细菌可以自我调节以作为对多壁碳纳米管毒性的适应性反应，值得注意的是，DNS32菌株在与多壁碳纳米管一起培养时通过修饰细胞膜中的脂肪酸呈现出适应性反应，但在暴露于多壁碳纳米管时未表现出类似的反应。这一结果可能与多壁碳纳米管的干扰有关，其超过了细胞的自我修复能力。透射电子显微镜（TEM）图像和对暴露于多壁碳纳米管的细菌的流式细胞术分析表明，DNS32菌株中细胞膜的破坏比枯草芽孢杆菌中的更严重，这表明材料与细菌之间的静电排斥导致直接接触减少可能是降低多壁碳纳米管影响的主要因素。
