Recent advances in single bacterium metabolic analysis techniques

Illuminating the Tiny World: A Navigation Guide for Proper Raman Studies on Microorganisms

“…Since Raman spectroscopy always samples all biomolecules inside the probing volume, most Raman methods are phenotypic which means the information of all biomolecules can be found in the Raman spectra of bacteria [ 15 , 16 , 17 , 18 , 19 ]. In principle, there are two types of Raman measurements of bacteria—bulk samples and single-cell measurements.…”

“…Lastly, it is also important to consider with which excitation wavelength the bacterial samples are excited to achieve the desired outcome, and whether single-cell, or bulk analysis, is performed. Especially for single-cell analysis the cell-to-cell variance should be considered [ 18 ]. In summary, these are just some of the many factors that may influence the bacterial phenotype and subsequently the Raman spectrum and chemometric evaluation [ 8 ].…”

“…The appropriate strain selection is mainly related to the nature of the study, the study topic, and the specific research question asked (Figure 3). Since Raman spectroscopy always samples all biomolecules inside the probing volume, most Raman methods are phenotypic which means the information of all biomolecules can be found in the Raman spectra of bacteria [15][16][17][18][19]. In principle, there are two types of Raman measurements of bacteria-bulk samples and single-cell measurements.…”

“…By applying this setup, it was possible to characterize isotopically labeled Escherichia coli cells and monitor their overall metabolism as well as metabolically active cells [54]. It is also quite useful to monitor cellular metabolic activity in E. coli with 18 O incorporated into the amide I group of proteins and DNA/RNA bases [124]. As previously mentioned, when choosing a wavelength in the deep UV region, the chances are high that nucleic acid and aromatic amino acid signals are enhanced.…”