【摘要】 为研究纳米银和银离子对土壤微生物的影响,采用土壤培养方式,对不同剂量纳米银(10、50、100 mg·kg^-1)和银离子(1、5、10 mg·kg^-1)暴露下黄褐土、砖红壤中可培养微生物数量及土壤酶活性（脲酶、荧光素二乙酸酯水解酶、蔗糖酶、过氧化氢酶）进行研究,并采用纯培养方法对纳米银和银离子暴露下的大肠杆菌（Escherichia coli）、金黄色葡萄球菌（Staphylococcus aureus）凋亡情况进行检测,对纳米银释放的银离子毒性进行评估。结果表明,随着纳米银剂量的增加,土壤可培养微生物数量显著减少,脲酶和过氧化氢酶活性降低,蔗糖酶、荧光素二乙酸酯水解酶（FDA酶）活性没有显著变化;银离子处理中微生物数量明显减少,但土壤酶活性被激活。10 mg·L^-1纳米银暴露1 h后大肠杆菌、金黄色葡萄球菌凋亡率、死亡率增高;随着培养时间的延长,纳米银缓慢释放银离子,并促进大肠杆菌的凋亡。综上分析,纳米银能够抑制土壤可培养微生物生长和酶活性,其中脲酶、过氧化氢酶对纳米银较为敏感,蔗糖酶、FDA酶受纳米银的影响较小;纳米银的毒性一方面是其本身的特异抗菌性,也有部分来自缓慢释放的银离子。更多还原

【Abstract】 In order to evaluate the microbial toxicity of silver nanoparticles（AgNP） and silver ions in soils, the incubation experiments were conducted to investigate the effect of nanosilver(0, 10, 50, 100 mg·kg^-1) and silver acetate(1, 5, 10 mg·kg^-1) on microbial population and enzyme activities（urease, fluorescein diacetate hydrolase, invertase and catalase） in yellow cinnama and laterite. The apoptotic cells of Escherichia coli and Staphylococcus aureus exposed to nanosilver and silver ions were also determined by the pure culture test, and silver ions released from nanosilver were evaluated. The results showed that with the increase of nanosilver content, the microbial quantities decreased significantly, the activities of urease and catalase decreased, but there was no significant changein invertase and fluorescein diacetate（FDA） hydrolase activities. The population of microorganisms in the silver acetate treatment significantly decreased, while the soil enzyme activities were activated. The apoptosis rate and mortality of Escherichia coli and Staphylococcus aureus increased after exposure to 10 mg·L^-1 nanosilver for 1 hour. As the culture time prolonged, nanosilver slowly released silver ions and promoted the apoptosis of E. coli In summary, nanosilver can inhibit the growth of culturable microorganisms and the activity of enzyme in soil. Urease and catalase are sensitive to nanosilver but invertase and FDA hydrolase are less affected by nanosilver. The toxicity of nanosilver is from its own specific antibacterial properties, also partly from the slow release of silver ions.更多还原