Department of Environmental Science, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea.
Appl Microbiol Biotechnol. 2011 Dec;92(5):1045-52. doi: 10.1007/s00253-011-3611-x. Epub 2011 Oct 11.
We assess the microbial assay-dependent effect of AgNP on gram-negative Escherichia coli and gram-positive Bacillus subtilis. The experiment was conducted via three different assays: a growth inhibition assay, a colony forming unit assay, and a liquid-to-plate assay. AgNP were exposed either as liquid suspensions or in an agar state. Bacterial sensitivity to AgNP was found to be dependent on the microbial assay employed. E. coli was more sensitive than B. subtilis in the growth inhibition and CFU assays, but B. subtilis was more vulnerable than E. coli in the liquid-to-plate assay, ostensibly owing to the food stress mechanisms of B. subtilis in exposure medium. The dissolution of silver from AgNP could not explain the observed toxicity of AgNP. We detected clear evidence of AgNP uptake by cells. The results of this study showed that the microbial toxicity of AgNP and the effects of dissolved silver ions were influenced profoundly by the microbial test method employed.
我们评估了微生物测定法对革兰氏阴性大肠杆菌和革兰氏阳性枯草芽孢杆菌中 AgNP 的影响。该实验通过三种不同的测定法进行：生长抑制测定法、集落形成单位测定法和液体到平板测定法。AgNP 以液体悬浮液或琼脂状态暴露。AgNP 对细菌的敏感性取决于所使用的微生物测定法。在生长抑制和 CFU 测定中，大肠杆菌比枯草芽孢杆菌更敏感，但在液体到平板测定中，枯草芽孢杆菌比大肠杆菌更脆弱，这主要是由于枯草芽孢杆菌在暴露介质中的食物应激机制。AgNP 从 AgNP 中的银溶解不能解释 AgNP 的观察到的毒性。我们检测到细胞摄取 AgNP 的明显证据。这项研究的结果表明，AgNP 的微生物毒性和溶解银离子的影响受到所使用的微生物测试方法的深刻影响。
