title: Antibacterial activity of silver nanoparticles target sara through srna-teg49, a key mediator of hfq, in staphylococcus aureus.
abstract: Attributed to its antimicrobial effect, Silver nanoparticles (AgNPs) is widely used in various fields, such as biomedicine, textiles, health care products and food, etc. However, the antibacterial mechanism of AgNPs in staphylococcus aureus (S. aureus) by regulating sRNA expression remains largely unknown.
  
  
  OBJECTIVE
  This study was performed to investigate the involvement of the antibacterial mechanism of AgNPs through sRNA-TEG49, a key mediator of Hfq, in S. aureus.
  
  
  METHODS
  Through the antimicrobial tests of AgNPs, its antibacterial laps and minimum inhibitory concentration was measured. A hierarchical cluster analysis of the differentially expressed sRNA in S. aureus was performed to investigate the relationship between AgNPs and sRNA. Expression of genes was analyzed by real-time PCR.
  
  
  RESULTS
  In the present study we found that at the concentrations higher than 1 mg/L, AgNPs could completely restrain bacteria growth, and the antibacterial activity of AgNPs apparently declined at the concentrations lower than 1 mg/L. S. aureus exposure to AgNPs, the expression of sRNA-TEG49, Hfq and sarA was significantly up-regulated in wild-type S. aureus. Moreover, Hfq loss-of-function inhibited the expression of sRNA-TEG49 in mutant-type S. aureus. Furthermore, sRNA-TEG49 loss-of-function associated with down-regulation the expression of sarA in mutant-type S. aureus.
  
  
  CONCLUSIONS
  It was reasonable that Hfq regulated a distinct underlying molecular and antibacterial mechanism of AgNPs by forming a positive feedback loop with sRNA-TEG49. These observations suggested that Hfq plays an important role in the antibacterial mechanism of AgNPs by regulating sRNA-TEG49 expression, via its target sarA.
authors.affiliation: Hepatobiliary and Enteric Surgery Research Center, Xiangya Hospital, Central South University Changsha 410008, Hunan, P. R. China.
authors.forename: Hu
authors.initials: H
authors.lastname: Tian
authors.affiliation: Hepatobiliary and Enteric Surgery Research Center, Xiangya Hospital, Central South University Changsha 410008, Hunan, P. R. China.
authors.forename: Qiande
authors.initials: Q
authors.lastname: Liao
authors.affiliation: Hepatobiliary and Enteric Surgery Research Center, Xiangya Hospital, Central South University Changsha 410008, Hunan, P. R. China.
authors.forename: Meizhou
authors.initials: M
authors.lastname: Liu
authors.affiliation: Hepatobiliary and Enteric Surgery Research Center, Xiangya Hospital, Central South University Changsha 410008, Hunan, P. R. China.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Hou
authors.affiliation: Hepatobiliary and Enteric Surgery Research Center, Xiangya Hospital, Central South University Changsha 410008, Hunan, P. R. China.
authors.forename: Yangde
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University Jinan 250014, Shandong, P. R. China.
authors.forename: Ju
authors.initials: J
authors.lastname: Liu
keywords: AgNPs; Hfq; sRNA-TEG49; sarA; staphylococcus aureus