Elken Emad Mohammed, Tan Zi-Ning, Wang Qian, Jiang Xiu-Yun, Wang Yu, Wang Yi-Ming, Ma Hong-Xia
College of Animal Medicine, Jilin Agricultural University, Changchun, China.
The Key Laboratory of New Veterinary Drug Research and Development of Jilin Province, Jilin Agricultural University, Changchun, China.
Front Vet Sci. 2022 Jul 12;9:945491. doi: 10.3389/fvets.2022.945491. eCollection 2022.
The Rcs phosphorelay system is present in many members of the . The aim of this study was to illustrate the possible mechanisms of eugenol on ultimate targets of () Rcs phosphorelay, , and impact on biofilm formation. The minimum inhibitory concentration (MIC) of eugenol against KP1 and KP1 Δ strain was determined using the 2-fold micro-dilution method. Biofilm was measured by crystal violet staining. Transcriptome sequencing was performed to investigate sub-MIC eugenol on , and gene expression at mRNA level was analyzed by RT-qPCR. biofilm formation test and molecular docking were used to evaluate the effect of eugenol and to predict potential interactions with RcsB. MicroScale Thermophoresis (MST) was conducted for further validation. MIC of eugenol against KP1 and KP1 Δ strain was both 200 μg/ml. Transcriptome sequencing and RT-qPCR results indicated that , and were downregulated, while , and were upregulated in the eugenol-treated group. Δ exhibited a weakened biofilm formation capacity. Additional isopropyl-β-d-thiogalactoside (IPTG) hinders biofilm formation, while sub-MIC eugenol could promote biofilm formation greatly. Docking analysis revealed that eugenol forms more hydrophobic bonds than hydrogen bonds. MST assay also showed a weak binding affinity between eugenol and RcsB. These results provide significant evidence that plays a key role in biofilm formation. Sub-MIC eugenol facilitates biofilm formation to a large extent instead of inhibiting it. Our findings reveal the potential risk of natural anti-biofilm ingredients at sub-MIC to treat drug-resistance bacteria.
Rcs磷信号传递系统存在于许多……成员中。本研究的目的是阐明丁香酚对Rcs磷信号传递（）的最终靶点的可能作用机制，以及对生物膜形成的影响。采用二倍稀释法测定丁香酚对肺炎克雷伯菌KP1及其Δ菌株的最低抑菌浓度（MIC）。通过结晶紫染色测定生物膜。进行转录组测序以研究亚MIC浓度的丁香酚对……的影响，并通过RT-qPCR分析mRNA水平的基因表达。采用生物膜形成试验和分子对接来评估丁香酚的作用，并预测其与RcsB的潜在相互作用。进行微量热泳动（MST）以进一步验证。丁香酚对肺炎克雷伯菌KP1及其Δ菌株的MIC均为200μg/ml。转录组测序和RT-qPCR结果表明，在丁香酚处理组中，……和……被下调，而……、……和……被上调。Δ菌株表现出减弱的生物膜形成能力。额外添加异丙基-β-D-硫代半乳糖苷（IPTG）会阻碍生物膜形成，而亚MIC浓度的丁香酚可极大地促进生物膜形成。对接分析表明，丁香酚形成的疏水键比氢键更多。MST分析也显示丁香酚与RcsB之间的结合亲和力较弱。这些结果提供了重要证据，表明……在……生物膜形成中起关键作用。亚MIC浓度的丁香酚在很大程度上促进生物膜形成而非抑制它。我们的研究结果揭示了亚MIC浓度的天然抗生物膜成分在治疗耐药细菌方面的潜在风险。
