纳米银在诺氟沙星胁迫下对黄孢原毛平革菌的毒物兴奋效应

Hormesis of Silver Nanoparticles on Phanerochaete chrysosporium under Norfloxacin Stress

具有生物毒性的纳米银(AgNPs)在低浓度下能产生毒物兴奋效应,可以刺激细胞的活性增强。研究了在诺氟沙星胁迫下,AgNPs对黄孢原毛平革菌活性的影响,并通过探究AgNPs的迁移转化以及细胞外蛋白质浓度的变化,结合扫描电镜、X射线衍射以及傅里叶红外光谱分析进行机理探索。结果表明,AgNPs在0.001 mg·L^(-1)和0.01 mg·L^(-1)浓度下可以将黄孢原毛平革菌的细胞活性提高1.29倍与1.51倍,而在1.3 mg·L^(-1) AgNPs的刺激下,细胞活性降低64%,同时,相同浓度的Ag离子仅对细胞产生毒性抑制作用。低浓度AgNPs可以在溶液相与生物相之间进行迁移,触发细胞生物学特性的变化,刺激细胞在面临诺氟沙星胁迫时产生较多的胞外蛋白质来减轻毒性抑制作用。黄孢原毛平革菌的菌丝表面存在的羟基、醛、酮和巯基等官能团可以将Ag离子还原为纳米氯化银和硫化银,在细胞表面聚集。

Low concentrations of silver nanoparticles(AgNPs)with biological toxicity can produce hormesis and stimulate the activity of cells.The effect of AgNPs on the activity of Phanerochaete chrysosporium was studied under the stress of norfloxacin.The mechanism was explored by investigating the migration and transformation of AgNPs as well as the concentration change of extracellular protein,combined with scanning electron microscope(SEM),X-ray diffraction(XRD),and Fourier transform infrared spectroscopy(FTIR).The results showed that the cell activity of Phanerochaete chrysosporium increased by 1.29 and 1.51 times as the concentrations of AgNPs were 0.001 mg·L^(-1) and 0.01 mg·L^(-1);it decreased by 64%when the concentration was 1.3 mg·L^(-1).And the same concentration of Ag ion could only inhibit cell activity.Low concentration of AgNPs can migrate between the solution phase and the biological phase,thus triggering the change of biological characteristics of cells,and stimulating cells to produce more extracellular proteins under the stress of norfloxacin to reduce toxicity inhibition.The functional groups such as hydroxyl group,aldehyde group,ketone group,and sulfhydryl group on the mycelial surface of Phanerochaete chrysosporium can reduce silver ions to AgCl-NPs and AgS-NPs,which can aggregate on the cell surface.