Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia.
Department of Clinical Sciences, College of Medicine, University of Sharjah, University City, Sharjah, United Arab Emirates.
BMC Microbiol. 2021 Feb 17;21(1):51. doi: 10.1186/s12866-021-02097-2.
Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study.
50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella.
The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates.
大肠杆菌 K1 可引起新生儿脑膜炎。为了理解此类细菌的病理学和生物学特性，转录组研究必不可少。最近，我们发现负载橙皮苷的纳米颗粒是针对大肠杆菌 K1 的新型潜在抗菌剂。在此，我们用负载橙皮苷的银纳米颗粒、单纯橙皮苷和银处理细菌，并测定 50%最小抑菌浓度。使用 Degust 软件进行 RNA-seq 差异基因表达分析，选择了一组与细胞应激反应和代谢相关的基因进行研究。
负载橙皮苷的银纳米颗粒对大肠杆菌 K1 的 50%最小抑菌浓度在 1 小时时达到 0.5μg/ml 的橙皮苷负载银纳米颗粒浓度，即 0.5μg/ml。差异基因分析显示，与未处理的大肠杆菌 K1 相比，负载橙皮苷的银纳米颗粒和单纯银处理的大肠杆菌 K1 中分别有 122 个基因（≥2-logFC，P<0.01）的表达发生改变。值得注意的是，阳离子外排基因（cusA 和 copA）和离子跨膜转运基因（rsxB）的表达水平分别增加了 2.6、3.1 和 3.3-logFC。观察到代谢基因和几个参与鞭毛协调的基因存在显著调节。
纳米颗粒的抗菌机制可能是由于破坏了大肠杆菌 K1 的细胞膜、氧化应激和代谢。进一步的研究将有助于更好地理解纳米颗粒治疗的遗传机制，并确定急需的新型抗菌药物候选物。
