蒲公英-银纳米颗粒对三文鱼源哈夫尼亚菌AHL型群体感应系统的抑制作用

The AHL Quorum Sensing Inhibitory Potential of Dandelion-Ag Nanoparticles Against Salmon-originated Hafnia sp.

群体感应(QS)是细菌间的一种通讯机制,抑制细菌QS系统可作为控制腐败菌的一种新策略,且可避免细菌耐药性的产生。本研究以AgNO3为银源,蒲公英植物提取物为还原剂,制备蒲公英-银纳米颗粒(D-AgNPs)。采用紫外可见吸收光谱、动态光散射、Zeta电位、X射线衍射、傅里叶变换红外光谱、扫描电镜和X射线能谱对其结构进行表征。结果表明:所合成的D-AgNPs为球形、平均粒径13.9 nm、Zeta电位值(-14.07±0.25)mV,主要含Ag(68.96%)和Cl(15.27%)两种元素。测定D-AgNPs对两株哈夫尼亚菌生长和受QS系统调控的生物被膜、N-酰基-L-高丝氨酸内酯(AHLs)、蛋白酶、胞外多糖、群集和泳动等毒力因子的影响,结果表明D-AgNPs对哈夫尼亚菌最小抑菌质量浓度(MIC)为128μg/mL,在1/16~1/2 MIC(8~64μg/mL)时可抑制哈夫尼亚菌生物被膜的形成,在1/128~1/32 MIC(1~4μg/mL)时促进其生物被膜形成。对AHLs、蛋白酶产生、群集和泳动均显示不同程度的抑制,而对胞外多糖的产生有一定促进作用。本研究证实D-AgNPs可作为一种QS抑制剂。

Quorum sensing(QS)is a communication pattern between bacteria,hence the inhibition of bacterial QS system could be used as a new strategy to the control the spoilage caused by bacteria,and to some extent could avoid the bacteria drug resistance.In the study,dandelion water extract mediated biosynthesis Ag nanoparticles(D-AgNPs)was prepared with AgNO3 as silver source and dandelion water extract as reducing agent.Its structure was characterized by ultraviolet visible absorption spectroscopy(UV-vis),dynamic light scattering(DLS),Zeta potential,X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM)and X-ray energy spectrum(EDS).It was found that the synthesized D-AgNPs were spherical,with an average particle size of 13.9 nm and Zeta potential of(-14.07±0.25)mV.The effects of D-AgNPs on the growth of two Hafnia strains and quorum sensing regulated virulence factors such as biofilm,AHLs,proteases,exopolysaccharides,swimming and swarming motilities were determined.It was found that the minimum inhibitory concentration of D-AgNPs against Hafnia was 128μg/mL,and could inhibit the formation of the biofilms of Hafnia at 1/16~1/2 MIC(8-64μg/mL),whereas promoted its biofilm formation at 1/128~1/32 MIC(1-4μg/mL).D-AgNPs showed different inhibition abilities on the AHLs and protease production,as well as swimming and swarming motilities;however,sub-MIC D-AgNPs promoted the production of exopolysaccharides.It is proved that D-AgNPs could be used as quorum sensing inhibitor.