Department of Microbiology, Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER), Puducherry, 605006, India.
Department of Chemistry, Pondicherry University, Kalapet, Puducherry, 605014, India.
Microb Pathog. 2017 Oct;111:99-107. doi: 10.1016/j.micpath.2017.08.017. Epub 2017 Aug 14.
Antimicrobial therapy against extensively drug-resistant (XDR) P. aeruginosa biofilms is less efficient compared to the treatment of equal bacterial counts of free-floating planktonic cells, which has become a serious threat in hospital environment. P. aeruginosa regulate their cooperative activities and physiological processes through a cell to cell chemical communication process called Quorum sensing (QS). This attracted our interest to synthesize, and to chemically characterize two anti-QS compounds, N-(4-{4-fluoroanilno} butanoyl) -l-homoserine lactone (FABHL) and N-(4-{4-chlororoanilno} butanoyl) -l-homoserine lactone (CABHL) to inhibit biofilm formation via disabling the QS circuits. Structural and morphological properties of these compounds were characterized by H Nuclear Magnetic Resonance (NMR), C NMR and High-resolution mass spectrometry (HRMS). Two biofilm forming XDR P. aeruginosa isolates were included in this study. Anti-biofilm property of FABHL or CABHL was confirmed by biofilm formation assay and it was shown to occur without affecting the bacterial growth. Anti-QS property of FABHL or CABHL was determined by evaluating the expression levels of QS genes (lasR and rhlR) by quantitative real time PCR (qRT-PCR). Although, FABHL and CABHL downregulates the expression levels of QS genes, lasR expression was significantly reduced. Molecular modeling studies revealed that the binding energy of FABHL and CABHL with LasR protein was -4.27 and -4.51, respectively. Hence, the synthesized compounds have the potential to serve as a potent anti-biofilm agent via disabling the QS systems. Lethality of FABHL and CABHL against PBMCs was assessed by 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphynyl tetrazolium bromide (MTT) assay. Cell viability was observed for both the compounds.
与游离浮游细胞的同等细菌计数相比，针对广泛耐药（XDR）铜绿假单胞菌生物膜的抗菌治疗效果较差，这在医院环境中已成为严重威胁。铜绿假单胞菌通过一种称为群体感应（QS）的细胞间化学通讯过程来调节其合作活动和生理过程。这引起了我们的兴趣，以合成和化学表征两种抗 QS 化合物，N-（4-{4-氟苯胺基}丁酰基）-l-高丝氨酸内酯（FABHL）和 N-（4-{4-氯苯胺基}丁酰基）-l-高丝氨酸内酯（CABHL），通过使 QS 电路失活来抑制生物膜形成。这些化合物的结构和形态特性通过 H 核磁共振（NMR）、C NMR 和高分辨率质谱（HRMS）进行了表征。本研究包括两种形成生物膜的 XDR 铜绿假单胞菌分离株。通过生物膜形成测定法证实了 FABHL 或 CABHL 的抗生物膜特性，结果表明它在不影响细菌生长的情况下发生。通过评估定量实时 PCR（qRT-PCR）中 QS 基因（lasR 和 rhlR）的表达水平来确定 FABHL 或 CABHL 的抗 QS 特性。尽管 FABHL 和 CABHL 下调了 QS 基因的表达水平，但 lasR 表达明显降低。分子建模研究表明，FABHL 和 CABHL 与 LasR 蛋白的结合能分别为-4.27 和-4.51。因此，合成的化合物具有通过使 QS 系统失能而作为有效的抗生物膜剂的潜力。通过 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴盐（MTT）测定法评估 FABHL 和 CABHL 对 PBMCs 的致死性。观察到两种化合物的细胞活力。
