选择6种常见海洋细菌,包括非光合细菌海杆菌(Marinobacter sp.)、盐单胞菌(Halomonas sp.)、交替单胞菌(Alteromonas sp.)、副溶血弧菌(Vibrio parahaemolyticus)以及光合细菌聚球藻(Synechococcus sp.)XM-24和299,并以模式菌大肠杆菌(Escherichia coli)和枯草芽胞杆菌(Bacillus subtilis)作为参照,通过测定生长曲线和生物量来表征纳米TiO2(0.1,1,10,100 mg/L)对其生长的影响,并通过测定叶绿素a含量来指示聚球藻的光合能力.结果显示:在低质量浓度下(0.1和1 mg/L)纳米TiO2对所试细菌的生长影响不显著(p>0.05),而在高质量浓度下(10和100 mg/L)纳米TiO2则会显著抑制其生长(p<0.01),并且浓度越大抑制效果越明显; 100 mg/L纳米TiO2对聚球藻299的叶绿素a合成也有抑制作用; 纳米TiO2对非光合细菌生长的抑制作用一般在18 h后显著显现(p<0.05),而对2种聚球藻生物量的影响则在6 d之后较为显著(p<0.05).研究结果将为进一步评估纳米TiO2对海洋生态环境安全造成的影响提供参考.
In order to evaluate the effects of nanometer materials on marine ecological environment,we investigated the effect of nano-TiO2(25 nm)on the growth of six common marine bacteria,including Marinobacter sp.,Halomonas sp.,Alteromonas sp.,Vibrio parahaemolyticus,and two marine cyanobacterial strains,Synechococcus sp. XM-24 and Synechococcus sp. 299,with two model strains,Escherichia coli and Bacillus subtilis,as controls.Growth curve and biomass were measured to assess the effect of different concentrations of nano-TiO2(0.1,1,10,100 mg/L)on the growth of tested bacteria.The chlorophyll a content of Synechococcus sp. was measured to test the photosynthetic activity.The results showed that low concentrations(0.1,1 mg/L)of nano-TiO2 had little effect(p>0.05)on marine bacteria,in both light and dark conditions,while high concentrations(10,100 mg/L)of nano-TiO2 inhibited the growth of marine bacteria.The inhibition effects became more remarkable as the concentration of nano-TiO2 increased,and 100 mg/L nano-TiO2 had inhibitory effect on the synthesis of chlorophyll a of Synechococcus sp. 299.The inhibitory effect of nano-TiO2 on the non-photosynthetic bacteria showed significant difference(p<0.05)after 18 h,while the same effect was shown for Synechococcus sp. after 6 d(p<0.05).This study can provide basic knowledge for assessing the effect of nano-TiO2 on marine ecological safety.
