纳米银对青岛近海浮游细菌活性的影响研究

纳米银广泛用于抗菌材料、医疗设备和其他抗菌产品。在纳米银产品的生产、运输、消费和处置过程中,纳米银将不可避免地释放到自然环境中,而水生生态系统是纳米银在自然界中重要的汇之一。本文以青岛近海为研究对象,采集现场海水进行实验室模拟培养,通过测定(48 h)不同浓度纳米银(0.5、5和50 mg/L)短期暴露下对表层海水中浮游细菌死亡率、蛋白质含量、碱性磷酸酶活性及氨肽酶活性的变化,研究纳米银对近岸海区浮游细菌生长和活性的影响。研究结果表明,在纳米银胁迫下细菌生长和活性受到显著抑制(P<0.05),高浓度组在培养4 h后死亡率达到最高值88.20%,随着暴露时间延长,纳米银胁迫组活细菌数量缓慢恢复、死亡率逐渐减小;纳米银对碱性磷酸酶活性和氨肽酶活性的抑制效应分别在培养4和8 h后达到最高,分别为8.58%和32.55%,在培养16 h后,酶活性开始缓慢上升,表现出对纳米银胁迫的适应性;纳米银组的蛋白质含量在培养8 h后达到最低,相比于对照组降低了29.80%,在培养后期同样有所升高,蛋白质含量接近于对照组。由此可见,纳米银对青岛近海浮游细菌的生长和活性都具有显著的抑制效应;不同浓度纳米银对细菌的抑制效应不同,纳米银浓度越高,抑制效应越明显(P<0.05),具有明显的浓度梯度效应;在培养后期,碱性磷酸酶活性和氨肽酶活性都有恢复,蛋白质含量上升,细菌死亡率下降,表明细菌对纳米银胁迫表现出一定的适应性。

Effect of Nano-Silver on Planktonic-Bacterial Activity in Qingdao Coastal Waters

Nano silver is widely used in antibacterial materials,medical equipment and other antibacterial products.In the production,transportation,consumption and disposal of nano-silver products,nano-silver will inevitably be released into the natural environment,and the aquatic ecosystem is one of the important sinks of nano-silver in nature.Based on Qingdao offshore as the research object,this paper collected the seawater for simulated culture in laboratory,by determining(48 h)different concentrations of nano silver(0.5,5 and 50 mg/L)short-term exposure in surface waters of planktonic bacteria mortality,protein content,alkaline phosphatase activity and the change of aminopeptidase activity,research the effects of silver nanoparticles on the growth and activity of planktonic bacteria in nearshore area.The results showed that the growth and activity of bacteria were significantly inhibited under the stress of silver nanoparticles(P<0.05),and the mortality of the high concentration group reached the maximum of 88.20%after 4 h of culture.With the extension of exposure time,the number of live bacteria in the silver nanoparticles stress group slowly recovered and the mortality gradually decreased.The inhibitory effects of silver nanoparticles on alkaline phosphatase activity and aminopeptidase activity were the highest after 4 h and 8 h culture,respectively(8.58%and 32.55%,respectively).After 16 h culture,the enzyme activity began to slowly increase,showing adaptability to silver nanoparticles stress.The protein content of the nano-silver group reached the lowest level after 8 h of culture,which was 29.80%lower than that of the control group,and also increased in the later stage of culture,and the protein content was close to that of the control group.It can be seen that nano-silver has a significant inhibitory effect on the growth and activity of phytoplankton in the offshore waters of Qingdao.Different concentrations of silver nanoparticles had different inhibitory effects on bacteria.The higher the concentration of silver nanoparticles was,the more significant the inhibitory effect was(P<0.05).At the later stage of culture,alkaline phosphatase activity and aminopeptidase activity were restored,protein content increased,and bacterial mortality decreased,indicating that bacteria showed certain adaptability to nano-silver stress.