Efficacy of Penicillin-Streptomycin as a Repellent on Chemotaxis Behavior of Escherichia Coli - Dataset

A wide range of chemicals have been found to cause negative chemotaxis in Escherichia coli. Here, we report Penicillin-Streptomycin (Pen-Strep) as a repellent that can repel different strains of E. coli. E. coli DH5α grown in LB broth. These bacterial solutions were exposed to 4% agar loaded with PenStrep as a drug releasing system in 12-well plates. Penicillin at 2500 units/ml (ug/ml for Streptomycin) concentrations (25%) of the PenStrep-Agar loading system were prepared for chemotaxis evaluation. Repelling of the E. coli was clearly observed via microscopy within 30 mins of the exposure. Moreover, continuous video acquisition and analysis by real-time recording over 8 hours showed a distinct region with a high density of cells in the region away from the repellant and vice-versa for the region close to the repellant. The optical density measurements indicated a considerable reduction in cell aggregation near the repellent, while a majority of the cells were observed to be distributed farther away from the repellent area. Stimulated single cell trajectory tracking showed movement away from the repellant in the y-direction at a velocity of 0.017 µm/s when exposed to 25% PenStrep chemical gradient. Unstimulated cells showed normal motility with repeated run-and-tumble movement in random direction in the control groups. This study provides a proof of concept for high-throughput analysis of the selective chemotaxis behavior of the microbial community by microbiome engineering to achieve the goal of beneficial biofilm formation to inhibit biofilm formation by corrosive bacteria.现已发现多种化学物质可引发大肠杆菌（Escherichia coli）产生负趋化性（negative chemotaxis）。本研究报道青霉素-链霉素（Penicillin-Streptomycin，Pen-Strep）作为一种驱避剂，能够驱避不同菌株的大肠杆菌。本实验使用在LB肉汤（LB broth）中培养的大肠杆菌DH5α。将上述细菌悬液暴露于12孔板中、搭载有Pen-Strep作为药物缓释体系的4%琼脂凝胶中。我们配制了占Pen-Strep-琼脂负载体系总比例25%的混合液：其中青霉素浓度为2500单位/毫升，链霉素浓度为微克/毫升级，用于趋化性评价。暴露后30分钟内即可通过显微镜清晰观察到大肠杆菌的驱避现象。此外，通过8小时的连续视频采集与实时记录分析，可发现远离驱避剂的区域存在细胞密度显著升高的独特区域，而靠近驱避剂的区域则恰好相反。光密度（optical density）检测结果显示，驱避剂附近的细胞聚集程度显著降低，而绝大多数细胞分布于远离驱避剂的区域。单菌轨迹追踪实验表明，当暴露于25% Pen-Strep化学梯度环境中时，大肠杆菌会沿y轴方向远离驱避剂运动，运动速度为0.017 μm/s。对照组中未受刺激的大肠杆菌则表现出正常的运动能力，以随机方向反复进行跑-翻运动（run-and-tumble）。本研究通过微生物组工程技术开展微生物群落选择性趋化行为的高通量分析，为实现构建有益生物被膜（biofilm）以抑制腐蚀性细菌形成生物被膜的目标提供了概念验证依据。