Abstract

Increasing prevalence of multidrug-resistant untreatable infections has prompted researchers to trial alternative treatments such as a substitute for traditional antibiotics. This study endeavored to elucidate the antibacterial mechanism(s) of this isoflavone, via analysis of relationship between genistein and Escherichia coli. Furthermore, this investigation analyzed whether genistein generates nitric oxide (NO) in E. coli as NO contributes to cell death. RecA, an essential protein for the bacterial SOS response, was detected through western blot, and the activated caspases decreased without RecA. The results showed that the NO induced by genistein affected the bacterial DNA. Under conditions of acute DNA damage, an SOS response called apoptosis-like death occurred, affecting DNA repair. These results suggested that RecA was bacterial caspase-like protein. In addition, NO was toxic to the bacterial cells and induced dysfunction of the plasma membrane. Thus, membrane depolarization and phosphatidylserine exposure were observed similarly to eukaryotic apoptosis. In conclusion, the combined results demonstrated that the antibacterial mode of action(s) of genistein was a NO-induced apoptosis-like death, and the role of RecA suggested that it contributed to the SOS response of NO defense.

Key points

• Genistein generates nitric oxide in E. coli.

• Genistein exhibits intense SOS response in E. coli.

• Genistein-induced NO causes apoptosis-like death in E. coli.

中文翻译：

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一氧化氮诱导金雀异黄素通过大肠杆菌中强烈的SOS反应引发凋亡样死亡。

摘要

多重耐药性无法治愈的感染的患病率上升，促使研究人员尝试替代疗法，例如替代传统抗生素。本研究通过分析金雀异黄素与大肠杆菌之间的关系，努力阐明该异黄酮的抗菌机制。此外，该研究还分析了染料木黄酮是否在大肠杆菌中产生一氧化氮（NO）。因为一氧化氮会导致细胞死亡。RecA是细菌SOS应答的必需蛋白，可通过Western印迹检测到，而没有RecA的情况下，活化的胱天蛋白酶降低。结果表明，染料木黄酮诱导的NO影响细菌DNA。在急性DNA损伤的情况下，发生了SOS反应，称为凋亡样死亡，影响了DNA修复。这些结果表明RecA是细菌半胱天冬酶样蛋白。另外，NO对细菌细胞有毒，并引起质膜功能障碍。因此，观察到膜去极化和磷脂酰丝氨酸暴露与真核细胞凋亡相似。总之，综合结果表明，染料木黄酮的抗菌作用是NO诱导的凋亡样死亡，

关键点

•金雀异黄素在大肠杆菌中产生一氧化氮。

•金雀异黄素在大肠杆菌中表现出强烈的SOS反应。

• Genistein诱导的NO在大肠杆菌中引起凋亡样死亡。