Lee Heejeong, Ji Young Rae, Ryoo Zae Young, Choi Myung-Sook, Woo Eun-Rhan, Lee Dong Gun
School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daehak-ro 80, Buk-gu, Daegu, 702-701, Republic of Korea.
Department of Food Science and Nutrition, Kyungpook National University, 1370 Sankyuk-dong Buk-gu, Daegu, 702-701, Republic of Korea.
Curr Microbiol. 2016 Jan;72(1):48-54. doi: 10.1007/s00284-015-0918-3. Epub 2015 Sep 29.
(-)-Nortrachelogenin is a lignan belonging to group of polyphenolic compounds. Its biological properties in mammalian cells are well-studied; however, its biological effects in microorganisms remain poorly understood. Its efficacy against pathogenic bacteria, including antibiotic-resistant strains, was investigated and it was found that bacteria are highly susceptible to the antibacterial effects of this compound. To investigate the antibacterial mode of action(s) against Escherichia coli O157, its effect on the penetration of SYTOX green into bacterial cells was assayed. The penetration of SYTOX Green into a bacterial cell is a measure of permeability of the plasma membrane. An increase in fluorescence intensity using bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)] and 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)] was also observed, indicating membrane depolarization. Potassium ion efflux from the cytosol into the extracellular matrix showed that cellular damage due to (-)-nortrachelogenin treatment resulted in the loss of intracellular components. While cells were damaged by (-)-nortrachelogenin, large unilamellar vesicles containing fluorescein isothiocyanate-dextran were perturbed to migrate molecules between 3.3 and 4.8 nm. The release of calcein from giant unilamellar vesicles, occurring as a result of disruption in artificial membranes, was visualized. Taken together, our results indicate that (-)-nortrachelogenin exerts its antibacterial effect by disorganizing and perturbing the cytoplasmic membrane, demonstrating the potential of this compound as a candidate for antibiotic drug development.
(-)-去甲rachelogenin是一种属于多酚类化合物的木脂素。其在哺乳动物细胞中的生物学特性已得到充分研究；然而，其在微生物中的生物学效应仍知之甚少。研究了其对包括耐抗生素菌株在内的病原菌的疗效，发现细菌对该化合物的抗菌作用高度敏感。为了研究其对大肠杆菌O157的抗菌作用方式，检测了其对SYTOX green进入细菌细胞的影响。SYTOX Green进入细菌细胞是细胞膜通透性的一种衡量指标。还观察到使用双-(1,3-二丁基巴比妥酸)三甲川氧杂菁[DiBAC4(3)]和3,3'-二丙基硫代碳菁碘化物[DiSC3(5)]时荧光强度增加，表明膜去极化。钾离子从细胞质溶胶外流到细胞外基质表明，(-)-去甲rachelogenin处理导致的细胞损伤导致细胞内成分流失。当细胞受到(-)-去甲rachelogenin损伤时，含有异硫氰酸荧光素-葡聚糖的大单层囊泡被扰动，以迁移3.3至4.8纳米之间的分子。可视化了由于人工膜破坏而导致的钙黄绿素从巨大单层囊泡中的释放。综上所述，我们的结果表明，(-)-去甲rachelogenin通过破坏和扰动细胞质膜发挥其抗菌作用，证明了该化合物作为抗生素药物开发候选物的潜力。
