Centre for Bioresource Research & Development (C-BIRD), Department of Biotechnology, Sathyabama Institute of Science and Technology, Chennai, 600119, Tamil Nadu, India.
Centre for Bioresource Research & Development (C-BIRD), Department of Biotechnology, Sathyabama Institute of Science and Technology, Chennai, 600119, Tamil Nadu, India.
Microb Pathog. 2020 Nov;148:104412. doi: 10.1016/j.micpath.2020.104412. Epub 2020 Aug 14.
Pseudomonas aeruginosa- major group of an aerobic bacteria associated with nosocomial and other life threatening infections. Diverse virulence factors produced by P. aeruginosa is due to distinct molecular cell signaling mechanism termed as quorum sensing (QS). Interfering with normal QS mechanism by active biomolecules is an effective strategy for attenuating its virulence. With this objective, the present study is undertaken to evaluate the inhibition of quorum sensing of clinical isolate of P. aeruginosa by repression of Las R-a transcriptional regulator for QS by ethanol extract of Terminalia chebula and Ficus racemosa. Las R repression by the plant extracts was measured in inhibition of various virulence factors like biofilm, pyocyanin production, total proteolytic activity, swarming and twisting motility. Fabrication of the extracted metabolites on the wound dressing and its effect on anti bacterial activity was also investigated. Compatibility of plant extracts on zebra fish development and blood cells was further studied. P. aeruginosa was isolated from the post operative patient and the isolated pure culture was identified by cultural, biochemical, molecular characteristics. Active principles of both the plants were readily extracted in ethanol and effectively repressed the expression of Las R. Both the tested plant extracts effectively repressed Las R expression which in turn affect the production of various virulence factors like biofilm formation, pyocyanin production, swarming motility, twisting motility, total proteolytic activity, cell adhesion and signaling molecule acyl honoserine lactone (AHL) production. Plant extract treatment brought about drastic reduction of all the tested virulence factors and AHL production. Extracted metabolites were fabricated on the wound dressing material adopting simple dip or immersion method reveals uniform coating, effective embedding of phytochemicals with the fibers and retained the anti bacterial activity against P. aeruginosa. Biocompatibility studies with zebra fish model shows both the tested plant extracts treatment was not exhibited any sign of toxicity on the developmental stages of Zebra fish. Hemolysis and changes in anti oxidative enzymes were not recorded in the plant extracts treated blood which demonstrated the best biocompatibility of the tested plant extracts. These results shows that the presence of potential phytochemicals in the ethanolic extract of Terminalia chebula and Ficus racemosa effectively represses the Las R followed by inhibition of quorum sensing mediated virulence factors production may be useful in the lead of anti bacterial drugs.
铜绿假单胞菌-与医院感染和其他危及生命的感染相关的需氧细菌的主要群体。铜绿假单胞菌产生的多种毒力因子归因于一种称为群体感应（QS）的独特分子细胞信号机制。通过活性生物分子干扰正常的 QS 机制是减弱其毒力的有效策略。基于此目的，本研究旨在通过乙醇提取物来评估通过抑制群体感应来抑制铜绿假单胞菌临床分离株的毒力，所述提取物来自诃子和榕属植物的 Las R-a 转录调节剂。通过植物提取物抑制各种毒力因子（如生物膜、绿脓菌素产生、总蛋白水解活性、群集和扭曲运动）来测量 Las R 的抑制。还研究了提取代谢物在伤口敷料上的构建及其对抑菌活性的影响。进一步研究了植物提取物对斑马鱼发育和血细胞的相容性。从术后患者中分离出铜绿假单胞菌，通过培养、生化和分子特征鉴定分离的纯培养物。两种植物的活性成分都很容易在乙醇中提取，并能有效地抑制 Las R 的表达。两种测试的植物提取物都有效地抑制了 Las R 的表达，这反过来又影响了生物膜形成、绿脓菌素产生、群集运动、扭曲运动、总蛋白水解活性、细胞黏附和信号分子酰基高丝氨酸内酯（AHL）产生等各种毒力因子的产生。提取物处理使所有测试的毒力因子和 AHL 产生都大幅减少。采用简单的浸渍或浸泡方法将提取的代谢物构建在伤口敷料材料上，显示出均匀的涂层，有效嵌入了纤维中的植物化学物质，并保留了对铜绿假单胞菌的抑菌活性。斑马鱼模型的生物相容性研究表明，两种测试的植物提取物处理在斑马鱼发育阶段均未表现出任何毒性迹象。在植物提取物处理的血液中未记录到溶血和抗氧化酶的变化，这表明测试的植物提取物具有最佳的生物相容性。这些结果表明，诃子和榕属植物的乙醇提取物中存在的潜在植物化学物质可有效抑制 Las R，随后抑制群体感应介导的毒力因子产生，这可能有助于开发抗菌药物。
