title: Antibacterial mechanism of soybean isoflavone on Staphylococcus aureus.
abstract: Effects of different flavonoids on various bacterial strains have been extensively reported; however, the mechanism(s) of their action on bacterial cells remain largely elusive. In this study, the antibacterial mechanism of soybean isoflavone (SI) on Staphylococcus aureus is systematically investigated using 4'6-diamidino-2-phenylindole (DAPI) staining, pBR322DNA decatenation experiment mediated by topoisomerase and agarose gel electrophoresis for direct decatenation. The results of fluorescence microscopy and fluorescence spectrophotometer indicated that DAPI was integrated in Staphylococcus aureus. Additionally, the quantity of both DNA and RNA reduced to 66.47 and 60.18%, respectively, after treated with SI for 28 h. Effects of SI on topoisomerase I and II were also investigated. SI completely inhibited the pBR322DNA unwinding mediated by topoisomerase I and topoisomerase II at the concentration of 6.4 mg/ml and could denature the plasmid DNA at the concentration of 12.8 mg/ml. These results indicate that topoisomerase I and II are the most important targets by SI to restrain bacterial cell division.
authors: College of Life Science, Liaoning Normal University, 116029, Dalian, People's Republic of China.
authors: Qian
authors: Q
authors: Wang
authors: Haitao
authors: H
authors: Wang
authors: Mingjie
authors: M
authors: Xie
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002455:Cell Division; D026942:DNA Topoisomerases / Q000187:drug effects; D004269:DNA, Bacterial / Q000096:biosynthesis / Q000187:drug effects; D007211:Indoles / Q000737:chemistry; D007529:Isoflavones / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013025:Glycine max / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D007211:Indoles; D007529:Isoflavones; C007293:DAPI; D026942:DNA Topoisomerases