Antibacterial activity and mechanism of action of ε-poly-L-lysine
| Autor: | Hong Xu, Yonghua Xiong, Ye Ruosong, Zheling Zeng, Peng Shanshan, Zoraida P. Aguilar, Hua Wei, Cuixiang Wan, Lijun Wang, Hengyi Xu |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Azides
Biophysics Virulence Food Contamination Biology medicine.disease_cause Escherichia coli O157 Microscopy Atomic Force Biochemistry Microscopy Electron Transmission medicine Polylysine SOS response Molecular Biology Escherichia coli Antibacterial agent Dose-Response Relationship Drug Cell Membrane Cell Biology Gene Expression Regulation Bacterial Molecular biology Acetylcysteine Anti-Bacterial Agents Oxidative Stress Regulon Food Microbiology bacteria Repressor lexA Antibacterial activity Reactive Oxygen Species Oxidation-Reduction Oxidative stress DNA Damage Propidium |
| Zdroj: | Biochemical and biophysical research communications. 439(1) |
| ISSN: | 1090-2104 |
| Popis: | e-Poly-L-lysine (e-PL)(2) is widely used as an antibacterial agent because of its broad antimicrobial spectrum. However, the mechanism of e-PL against pathogens at the molecular level has not been elucidated. This study investigated the antibacterial activity and mechanism of e-PL against Escherichia coli O157:H7 CMCC44828. Propidium monoazide-PCR test results indicated that the threshold condition of e-PL for complete membrane lysis of E. coli O157:H7 was 10 μg/mL (90% mortality for 5 μg/mL). Further verification of the destructive effect of e-PL on cell structure was performed by atomic force microscopy and transmission electron microscopy. Results showed a positive correlation between reactive oxygen species (ROS)(3) levels and e-PL concentration in E. coli O157:H7 cells. Moreover, the mortality of E. coli O157:H7 was reduced when antioxidant N-acetylcysteine was added. Results from real-time quantitative PCR (RT-qPCR)(4) indicated that the expression levels of oxidative stress genes sodA and oxyR were up-regulated 4- and 16-fold, respectively, whereas virulence genes eaeA and espA were down-regulated after e-PL treatment. Expression of DNA damage response (SOS response)(5) regulon genes recA and lexA were also affected by e-PL. In conclusion, the antibacterial mechanism of e-PL against E. coli O157:H7 may be attributed to disturbance on membrane integrity, oxidative stress by ROS, and effects on various gene expressions, such as regulation of oxidative stress, SOS response, and changes in virulence. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect