Azemtsop Matanfack Georgette, Pistiki Aikaterini, Rösch Petra, Popp Jürgen
Institute of Physical Chemistry and Abbe Center of Photonics (IPC), Friedrich-Schiller-University Jena, Helmholtzweg 4, 07743 Jena, Germany.
Leibniz Institute of Photonic Technology (Leibniz-IPHT), Member of Leibniz Research Alliance "Health Technologies", Albert-Einstein-Straße 9, 07745 Jena, Germany.
Life (Basel). 2021 Sep 24;11(10):1003. doi: 10.3390/life11101003.
Raman stable isotope probing (Raman-SIP) is an excellent technique that can be used to access the overall metabolism of microorganisms. Recent studies have mainly used an excitation wavelength in the visible range to characterize isotopically labeled bacteria. In this work, we used UV resonance Raman spectroscopy (UVRR) to evaluate the spectral red-shifts caused by the uptake of isotopes (C, N, H(D) and O) in cells. Moreover, we present a new approach based on the extraction of labeled DNA in combination with UVRR to identify metabolically active cells. The proof-of-principle study on revealed heterogeneities in the Raman features of both the bacterial cells and the extracted DNA after labeling with C, N, and D. The wavelength of choice for studying O- and deuterium-labeled cells is 532 nm is, while C-labeled cells can be investigated with visible and deep UV wavelengths. However, N-labeled cells are best studied at the excitation wavelength of 244 nm since nucleic acids are in resonance at this wavelength. These results highlight the potential of the presented approach to identify active bacterial cells. This work can serve as a basis for the development of new techniques for the rapid and efficient detection of active bacteria cells without the need for a cultivation step.
拉曼稳定同位素探测（Raman-SIP）是一种可用于探究微生物整体代谢的出色技术。近期研究主要使用可见光范围内的激发波长来表征同位素标记的细菌。在这项工作中，我们使用紫外共振拉曼光谱（UVRR）来评估细胞中同位素（碳、氮、氢（氘）和氧）摄取所引起的光谱红移。此外，我们提出了一种基于提取标记DNA并结合UVRR来鉴定代谢活跃细胞的新方法。原理验证研究揭示了用碳、氮和氘标记后细菌细胞和提取的DNA的拉曼特征存在异质性。研究氧和氘标记细胞的首选波长是532纳米，而碳标记细胞可以用可见光和深紫外波长进行研究。然而，氮标记细胞最好在244纳米的激发波长下进行研究，因为核酸在此波长下会发生共振。这些结果突出了所提出方法在鉴定活性细菌细胞方面的潜力。这项工作可为开发无需培养步骤即可快速高效检测活性细菌细胞的新技术奠定基础。
