Biophysics Graduate Group, University of California, Davis, California 95616, USA.
Anal Chem. 2010 Apr 1;82(7):2703-10. doi: 10.1021/ac902351a.
Laser tweezers Raman spectroscopy (LTRS) was used to characterize the Raman fingerprints of the metabolic states of Escherichia coli (E. coli) cells and to determine the spectral changes associated with cellular response to the antibiotic Cefazolin. The Raman spectra of E. coli cells sampled at different time points in the bacterial growth curve exhibited several spectral features that enabled direct identification of the growth phase of the bacteria. Four groups of Raman peaks were identified based on similarities in the time-dependent behavior of their intensities over the course of the growth curve. These groupings were also consistent with the different biochemical species represented by the Raman peaks. Raman peaks associated with DNA and RNA displayed a decrease in intensity over time, while protein-specific Raman vibrations increased at different rates. The adenine ring-breathing mode at 729 and the 1245 cm(-1) vibration peaked in intensity within the first 10 h and decreased afterward. Application of principal component analysis (PCA) to the Raman spectra enabled accurate identification of the different metabolic states of the bacterial cells. The Raman spectra of cells exposed to Cefazolin at the end of log phase exhibited a different behavior. The 729 and 1245 cm(-1) Raman peaks showed a slight decrease in intensity from 4 to 10 h after inoculation. Moreover, a shift in the spectral position of the adenine ring-breathing mode from 724 to 729 cm(-1), which was observed during normal bacterial growth, was inhibited during antibiotic drug treatment. These results suggest that potential Raman markers exist that can be used to identify E. coli cell response to antibiotic drug treatment.
激光镊子拉曼光谱（LTRS）用于表征大肠杆菌（E. coli）细胞代谢状态的拉曼指纹，并确定与细胞对头孢唑林抗生素反应相关的光谱变化。在细菌生长曲线的不同时间点采集的大肠杆菌细胞的拉曼光谱显示了几个光谱特征，这些特征能够直接识别细菌的生长阶段。根据强度随生长曲线变化的时间依赖性行为的相似性，确定了四组拉曼峰。这些分组也与拉曼峰所代表的不同生化物质一致。与 DNA 和 RNA 相关的拉曼峰的强度随时间降低，而蛋白质特异性拉曼振动以不同的速率增加。腺嘌呤环呼吸模式在 729 和 1245 cm(-1) 振动在 10 小时内达到峰值，之后强度降低。对拉曼光谱进行主成分分析（PCA）可以准确识别细菌细胞的不同代谢状态。对数生长期结束时暴露于头孢唑林的细胞的拉曼光谱表现出不同的行为。729 和 1245 cm(-1) 拉曼峰在接种后 4 至 10 小时内强度略有下降。此外，在正常细菌生长过程中观察到的腺嘌呤环呼吸模式的光谱位置从 724 到 729 cm(-1) 的移动在抗生素药物治疗期间受到抑制。这些结果表明，可能存在可以用于识别大肠杆菌细胞对抗生素药物治疗反应的潜在拉曼标记物。
