Effect of a fullerene water suspension on bacterial phospholipids and membrane phase behavior
Effect of a fullerene water suspension on bacterial phospholipids and membrane phase behavior
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DOI：
10.1021/es062181w
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发表时间：
2007-04-01
影响因子：
11.4
通讯作者：
Alvarez, Pedro J. J.
中科院分区：
文献类型：
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作者：
Fang, Jiasong;Lyon, Delina Y.;Alvarez, Pedro J. J.
几种基于富勒烯的纳米材料会产生活性氧物质，从而损害细胞。在这项研究中，我们研究了巴克敏斯特富勒烯（C-60）作为胶体聚集体引入水中（nC（60））对细菌膜脂质组成和相行为的影响。恶臭假单胞菌（革兰氏阴性菌）和枯草芽孢杆菌（革兰氏阳性菌）通过改变膜脂质组成、相变温度和膜流动性对nC（60）作出反应。恶臭假单胞菌在nC（60）存在下降低了其不饱和脂肪酸的水平，并增加了环丙烷脂肪酸的比例，可能是为了保护细菌膜免受氧化应激。完整细菌细胞的傅立叶变换红外光谱测量显示，在高生长抑制浓度（0.5 mg L-1）的nC（60）存在下生长的细胞的相变温度（T-m）略有增加，膜流动性增加。B。枯草芽孢杆菌对低剂量nC（60）（0.01 mg L-1）的反应是通过显著增加异支链和反异支链脂肪酸的水平（分别从总脂肪酸的5.8%至31.5%和12.9%至32.3%），对高生长抑制浓度的nC（60）（0.75 mg L-1）的反应是通过增加单不饱和脂肪酸的合成。与恶臭假单胞菌（P. putida）相比，B.枯草杆菌的反应是T-m降低和膜流动性增加。这些发现代表了细菌对人造纳米材料的第一次证明的生理适应反应，并且它们表明脂质组成和膜相行为的反应取决于nC（60）浓度和细胞壁形态。
Several fullerene-based nanomaterials generate reactive oxygen species that can damage cells. In this study, we investigated the effect of buckminsterfullerene (C-60) introduced as colloidal aggregates in water (nC(60)) on bacterial membrane lipid composition and phase behavior. Pseudomonas putida (Gram-negative) and Bacillus subtilis (Gram-positive) responded to nC(60) by altering membrane lipid composition, phase transition temperature, and membrane fluidity. P. putida decreased its levels of unsaturated fatty acids and increased the proportions of cyclopropane fatty acids in the presence of nC(60), possibly to protect the bacterial membrane from oxidative stress. Fourier transform infrared spectroscopy measurement of intact bacterial cells showed slightly increased phase transition temperatures (T-m) and increased membrane fluidity for cells grown in the presence of high, growth-inhibiting concentrations (0.5 mg L-1) of nC(60). B. subtilis responded to a low dose of nC(60) (0.01 mg L-1) by significantly increasing the levels of iso- and anteiso-branched fatty acids (from 5.8 to 31.5% and 12.9 to 32.3% of total fatty acids, respectively) and to a high, growth-inhibiting concentration of nC(60) (0.75 mg L-1) by increasing synthesis of monounsaturated fatty acids. In contrast to P. putida, B. subtilis response was a decrease in T-m and an increase in membrane fluidity. These findings represent the first demonstrated physiological adaptation response of bacteria to a manufactured nanomaterial, and they show that response in lipid composition and membrane phase behavior depends on both the nC(60) concentration and the cell wall morphology.