School of Environmental Science and Engineering, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Jun;25(17):17128-17136. doi: 10.1007/s11356-018-1894-5. Epub 2018 Apr 11.
The interactions between antibiotics and microorganisms have attracted enormous research attentions. In this study, we investigated the effects of two typical aminoglycoside antibiotics on the aggregation of the model cyanobacterium, Synechococcus elongatus, and the dominating strain in algal blooms, Microcystis aeruginosa, via the analysis of zeta potentials, hydrophobicity, and extracellular polymeric substances (EPS) secretion. The results showed that low-level antibiotics promoted the aggregation of S. elongatus and M. aeruginosa by 40 and 18% under 0.10 and 0.02 μg/mL of kanamycin, respectively, which was mainly attributed to the combined effects of increased zeta potentials and the ratio between extracellular proteins and polysaccharides. Tobramycin exerted similar effects. Additionally, we discovered that at low pH (pH 5) and ionic strength (1 mM Na and 2 mM Mg), the inducing effects of antibiotics would be even larger than those with higher pH and ionic strength. As aggregation is important to cyanobacteria in either the basic physiology of biofilm formation or the algal bloom, our study demonstrated that low-level antibiotics exert ecological impacts via interfered aggregation. We believe this study will shed light on the mechanisms underlying antibiotic-induced biofilm formation and help with the evaluation of the environmental and ecological risks of antibiotics and other emerging pollutants.
抗生素与微生物之间的相互作用引起了人们的极大关注。在这项研究中，我们通过分析zeta 电位、疏水性和胞外聚合物（EPS）分泌，研究了两种典型的氨基糖苷类抗生素对模式蓝藻鱼腥藻和水华优势种铜绿微囊藻聚集的影响。结果表明，在 0.10 和 0.02μg/mL 卡那霉素作用下，低浓度抗生素分别促进了鱼腥藻和铜绿微囊藻的聚集，促进率分别为 40%和 18%，这主要归因于 zeta 电位增加和胞外蛋白与多糖比例的共同作用。妥布霉素也有类似的作用。此外，我们发现，在低 pH（pH 5）和离子强度（1 mM Na 和 2 mM Mg）下，抗生素的诱导作用甚至比在较高 pH 和离子强度下更大。由于聚集对蓝藻在生物膜形成或水华的基本生理过程中都很重要，我们的研究表明，低浓度抗生素通过干扰聚集对生态系统产生影响。我们相信这项研究将揭示抗生素诱导生物膜形成的机制，并有助于评估抗生素和其他新兴污染物的环境和生态风险。
