纳米银抑制铜绿微囊藻的机理研究

Studies on the inhibitory mechanism of silver nanoparticles on Microcystis aeruginosa

[目的]纳米银可以抑制铜绿微囊藻的繁殖及减少其叶绿素a的合成,但具体机理还不清楚,该研究探讨纳米银抑制铜绿微囊藻的生化和分子机理。[方法]用琼脂糖凝胶电泳法检测了经纳米银作用后铜绿微囊藻基因组的降解情况,用硫代巴比妥酸(TBA)法检测了细胞膜氧化产物丙二醛(MDA)的含量及用实时荧光定量PCR检测了叶绿素a合成基因chl L的表达量的变化。[结果]经纳米银作用后的铜绿微囊藻的基因组电泳图显示相对严重的断裂现象,丙二醛含量明显增多,叶绿素合成基因chl L的表达量也显著下降。[结论]纳米银可以损坏铜绿微囊藻的细胞膜与基因组,进而影响基因表达,使叶绿素合成相关的chl L基因表达量显著下降,抑制铜绿微囊藻的繁殖,甚至致其死亡。

[Objective]Microcystis aeruginosa is the preponderant microbe in freshwater bloom. Silver nanoparticles（SNPs） can inhibit M. aeruginosa＇s reproduction and reduce synthesis of chlorophyll A,however,the biochemical and molecular biological mechanism of the antibacterial activity of silver nanoparticles has not been elucidated so far. The objective is to further study on the mechanism of the antibacterial activity of silver nanoparticles. [Methods]The genome DNA of M. aeruginosa exposed to SNPs was analyzed with agarose gel electrophoresis. The quantity of malonaldehyde（MDA）,the cytomembrane＇s oxydate,was measured with thiobarbituric acid（TBA）method. Real-time fluorescence quantitative polymerase chain reaction（RT-PCR） was performed to measure the expression level of chl L,one of chlorophyll A biosynthesis genes. [Results]The electrophoretogram of the test group displayed a relatively serious smear of broken DNA molecules,the quantity of MDA increases significantly,and the expression level of chlorophyll biosynthesis gene chl L decreased dramatically compared with the control group. [Conclusion]SNPs could damage M. aeruginosa＇s cell membrane,cut off their genome and then affect their gene expression of chlorophyll A biosynthesis,inhibit the reproduction of M. aeruginosa and even kill them.