School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Appl Microbiol Biotechnol. 2014 Jan;98(2):855-62. doi: 10.1007/s00253-013-5377-9. Epub 2013 Nov 29.
A novel bacterial growth monitoring method using a tunable resistive pulse sensor (TRPS) system is introduced in this study for accurate and sensitive measurement of cell size and cell concentration simultaneously. Two model bacterial strains, Bacillus subtilis str.168 (BSU168) and Escherichia coli str.DH5α (DH5α), were chosen for benchmarking the growth-monitoring performance of the system. Results showed that the technique of TRPS is sensitive and accurate relative to widely used methods, with a lower detection limit of cell concentration measurement of 5 × 10⁵ cells/ml; at the same time, the mean coefficient of variation from TRPS was within 2 %. The growth of BSU168 and DH5α in liquid cultures was studied by TRPS, optical density (OD), and colony plating. Compared to OD measurement, TRPS-measured concentration correlates better with colony plating (R = 0.85 vs. R = 0.72), which is often regarded as the gold standard of cell concentration determination. General agreement was also observed by comparing TRPS-derived cell volume measurements and those determined from microscopy. We have demonstrated that TRPS is a reliable method for bacterial growth monitoring, where the study of both cell volume and cell concentration are needed to provide further details about the physical aspects of cell dynamics in real time.
本研究引入了一种使用可调电阻脉冲传感器 (TRPS) 系统的新型细菌生长监测方法，用于同时准确和敏感地测量细胞大小和细胞浓度。选择枯草芽孢杆菌 str.168 (BSU168) 和大肠杆菌 str.DH5α (DH5α) 两种模型细菌菌株来基准测试该系统的生长监测性能。结果表明，TRPS 技术相对于广泛使用的方法具有较高的灵敏度和准确性，细胞浓度测量的检测限低至 5×10⁵ 个细胞/ml；同时，TRPS 的平均变异系数在 2%以内。通过 TRPS、光密度 (OD) 和菌落平板计数研究了 BSU168 和 DH5α 在液体培养物中的生长情况。与 OD 测量相比，TRPS 测量的浓度与菌落平板计数相关性更好 (R=0.85 与 R=0.72)，后者通常被认为是细胞浓度测定的金标准。通过比较从显微镜确定的 TRPS 衍生的细胞体积测量值和那些值，也观察到了一般的一致性。我们已经证明，TRPS 是一种可靠的细菌生长监测方法，其中需要研究细胞体积和细胞浓度，以实时提供有关细胞动力学物理方面的更多详细信息。
