Chair for Microbiology and Microbial Biotechnology, University of Ljubljana, Groblje 3, 1230, Domžale, Slovenia.
Folia Microbiol (Praha). 2012 Jul;57(4):363-5. doi: 10.1007/s12223-012-0143-4. Epub 2012 Apr 14.
One of the main mechanisms of nanoparticle toxicity is known to be the generation of reactive oxygen species (ROS) which primarily damage cell membranes. However, very limited data on membrane effects in anaerobic environments (where ROS could not be the cause of membrane damage) are available. In the following study, rumen anaerobe Ruminococcus flavefaciens 007C was used as a bacterial model to assess the potential effects of Al(2)O(3) and TiO(2) nanoparticles on membranes in an anaerobic environment. Fatty acid profiles of cultures after exposure to Al(2)O(3) or TiO(2) nanoparticles were analyzed and compared with the profiles of non-exposed cultures or cultures exposed to bulk materials. Analysis revealed dose-effect changes in membrane composition exclusively when cells were exposed to Al(2)O(3) nanoparticles in a concentration range of 3-5 g/L, but were not present in cultures exposed to bulk material. On the other hand, the tested concentrations of nano-TiO(2) did not significantly affect the membrane profile of the exposed bacterium. The results suggest the possibility that Al(2)O(3) induces changes in bacterial membranes by direct physical interaction, which was supported by TEM image analysis.
纳米颗粒毒性的主要机制之一是已知的活性氧物质 (ROS) 的产生，ROS 主要破坏细胞膜。然而，在厌氧环境中（ROS 不可能是膜损伤的原因），关于膜效应的非常有限的数据是可用的。在以下研究中，瘤胃厌氧菌 Ruminococcus flavefaciens 007C 被用作细菌模型，以评估 Al(2)O(3)和 TiO(2)纳米颗粒在厌氧环境中对膜的潜在影响。暴露于 Al(2)O(3)或 TiO(2)纳米颗粒后的培养物的脂肪酸谱进行了分析，并与未暴露的培养物或暴露于块状材料的培养物的谱进行了比较。分析显示，当细胞暴露于 3-5 g/L 的 Al(2)O(3)纳米颗粒浓度范围内时，膜组成会发生剂量效应变化，但在暴露于块状材料的培养物中不存在。另一方面，测试浓度的纳米 TiO(2) 并没有显著影响暴露细菌的膜谱。结果表明，Al(2)O(3)通过直接物理相互作用引起细菌膜的变化，这得到了 TEM 图像分析的支持。
