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首页> 外文期刊>Environmental Science & Technology >Modification of Fatty Acids in Membranes of Bacteria: Implication for an Adaptive Mechanism to the Toxicity of Carbon Nanotubes
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Modification of Fatty Acids in Membranes of Bacteria: Implication for an Adaptive Mechanism to the Toxicity of Carbon Nanotubes

机译：细菌膜中脂肪酸的修饰：对碳纳米管毒性适应机制的意义。

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We explored whether bacteria could respond adaptively to the presence of carbon nanotubes (CNTs) by investigating the influence of CNTs on the viability, composition of fatty acids, and cytoplasmic membrane fluidity of bacteria in aqueous medium for 24 h exposure. The CNTs included long single-walled carbon nanotubes (L-SWCNTs), short single-walled carbon nanotubes (S-SWCNTs), short carboxyi single-walled carbon nanotubes (S-SWCNT-COOH), and aligned multiwalled carbon nanotubes (A-MWCNTs). The bacteria included three common model bacteria, Staphyloccocus aureus (Gram-positive), Bacillus subtilis (Gram-positive), and Escherichia coli (Gram-negative), and one polybrominated diphenyl ether degrading strain, Ochrobactrum sp. (Gram-negative). Generally, L-SWCNTs were the most toxic to bacteria, whereas S-SWCNT-COOH showed the mildest bacterial toxicity. Ochrobactrum sp. was more susceptible to the toxic effect of CNTs than E. coli. Compared to the control in the absence of CNTs, the viability of Ochrobactrum sp. decreased from 71.6-81.4％ to 41.8-70.2％, and E. coli from 93.7-104.0％ to 67.7-91.0％ when CNT concentration increased from 10 to 50 mg L~(-1). The cytoplasmic membrane fluidity of bacteria increased with CNT concentration, and a significant negative correlation existed between the bacterial viabilities and membrane fluidity for E. coli and Ochrobactrum sp. (p ＜ 0.05), indicating that the increase in membrane fluidity induced by CNTs was an important factor causing the inactivation of bacteria. In the presence of CNTs, E. coli and Ochrobactrum sp. showed elevation in the level of saturated fatty acids accompanied with reduction in unsaturated fatty acids, compensating for the fluidizing effect of CNTs. This demonstrated that bacteria could modify their composition of fatty acids to adapt to the toxicity of CNTs. In contrast, S. aureus and B. subtilis exposed to CNTs increased the proportion of branched-chain fatty acids and decreased the level of straight-chain fatty acids, which was also favorable to counteract the toxic effect of CNTs. This study suggests that the bacterial tolerances to CNTs are associated with both the adaptive modification of fatty acids in the membrane and the physicochemical properties of CNTs. This is the first report about the physiologically adaptive response of bacteria to CNTs, and may help to further understand the ecotoxicological effects of CNTs.
机译：我们通过研究碳纳米管对细菌在水性介质中暴露24小时后的活力，脂肪酸组成和细胞质膜流动性的影响，探讨了细菌是否可以对碳纳米管（CNT）的存在做出自适应反应。碳纳米管包括长的单壁碳纳米管（L-SWCNT），短的单壁碳纳米管（S-SWCNT），短的羧基单壁碳纳米管（S-SWCNT-COOH）和排列的多壁碳纳米管（A- MWCNTs）。细菌包括三种常见的模型细菌：金黄色葡萄球菌（革兰氏阳性），枯草芽孢杆菌（革兰氏阳性）和大肠杆菌（革兰氏阴性），以及一种多溴二苯醚降解菌株Ochrobactrum sp。 （革兰氏阴性）。通常，L-SWCNT对细菌毒性最大，而S-SWCNT-COOH显示最温和的细菌毒性。 ch骨菌属比大肠杆菌更容易受到CNTs的毒性作用。与没有CNTs的对照相比，Ochrobactrum sp。的生存力。当CNT浓度从10 mg L〜（-1）增加时，大肠杆菌从93.7-104.0％降低到41.8-70.2％，大肠杆菌从93.7-104.0％降低到67.7-91.0％。细菌的细胞质膜流动性随CNT浓度的增加而增加，并且细菌的活力和膜流动性之间存在显着的负相关，而大肠埃希菌和Ochrobactrum sp。 （p ＜0.05），表明CNTs引起的膜流动性增加是引起细菌失活的重要因素。在存在CNT的情况下，大肠杆菌和Ochrobactrum sp。碳纳米管显示饱和脂肪酸水平升高，同时不饱和脂肪酸减少，弥补了碳纳米管的流化作用。这证明细菌可以改变其脂肪酸组成以适应CNT的毒性。相反，暴露于CNT的金黄色葡萄球菌和枯草芽孢杆菌增加了支链脂肪酸的比例，降低了直链脂肪酸的含量，这也有利于抵消CNT的毒性作用。这项研究表明，细菌对碳纳米管的耐受性与膜中脂肪酸的适应性修饰和碳纳米管的理化特性有关。这是关于细菌对碳纳米管的生理适应性反应的第一份报告，可能有助于进一步了解碳纳米管的生态毒理作用。

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  • 来源
    《Environmental Science & Technology》 |2014年第7期|4086-4095|共10页
  • 作者

    Baotong Zhu; Xinghui Xia; Na Xia; Shangwei Zhang; Xuejun Guo;

  • 作者单位

    School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation/Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875, People's Republic of China;

    School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation/Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875, People's Republic of China;

    School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation/Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875, People's Republic of China;

    Department of Isotope Biogeochemistry,, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, Leipzig 04318, Germany,Department of Ecological Chemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, Leipzig 04318, Germany;

    School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation/Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875, People's Republic of China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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