纳米二硫化钼促进粪肠球菌中信息素诱导质粒介导的耐药基因接合转移

Molybdenum Disulfide Promotes Pheromone-induced Plasmid Mediated Conjugation Transfer of Drug Resistance Genes in Enterococcus faecalis

粪肠球菌是一种通常寄居在人和动物胃肠道中的机会致病菌,并广泛存在于环境中。其可通过基因的水平转移获得抗生素抗性。纳米二硫化钼(molybdenum disulfide,MoS_(2))是一种新型的二维层状材料,有广泛的应用前景,但缺乏对纳米MoS_(2)完整的生物安全评价。本研究以粪肠球菌为接合模型,将纳米MoS_(2)加入接合体系中研究其对信息素诱导质粒pCF10接合转移的影响。研究发现,纳米MoS_(2)具有促进接合转移的作用,其中25 mg·L^(-1)的纳米MoS_(2)促进效果最明显,可以将接合频率提高5倍~8倍。因为纳米MoS_(2)良好的生物相容性对细胞膜通透性、细胞内活性氧水平和接合转移调控基因的表达都没有产生明显影响。纳米MoS_(2)具有吸附性能,而且又是片层状的结构,这使得其可以附着在细菌表面,促进细菌的聚集,进而促进pCF10质粒接合转移的发生。

Enterococcus faecalis is an opportunistic pathogen that usually resides in the gastrointestinal tract of humans and animals and widely exists in the environment.It can acquire antibiotic resistance through horizontal gene transfer and facilitate the spread of antibiotics resistance genes(ARGs).The problem of bacterial resistance is becoming increasingly serious,resulting in increased economic losses and deaths.Molybdenum disulfide(MoS_(2))is a new kind of two-dimensional layered material,which has a wide application prospect,but the complete biosafety evaluation of MoS_(2) is still lacking.In this study,Enterococcus faecalis was used as the conjugation model bacterium,and nano-MoS_(2) was added into the conjugation system to study its effect on the conjugation transfer of the plasmid pCF10.It was found that nano-MoS_(2) can promote conjugation transfer,and 25 mg·L^(-1) nano-MoS_(2) has the most obvious effect,which can increase the conjugation frequency by 5~8 times.Because of the good biocompatibility of nano-MoS_(2),it has no significant impact on cell membrane permeability,intracellular reactive oxygen species level and the expression of conjugation and transfer regulation genes.Nano-MoS_(2) can attach to the surface of bacteria to aggregate bacteria,and then promote the conjugation transfer of pCF10 plasmid due to its adsorption properties and lamellar structure.Adhesion of bacteria is an important prerequisite for the occurrence of conjugation transfer,which may be the reason why nano-MoS_(2) promotes conjugation transfer.