title: Multidimensional information on the chemical composition of single bacterial cells by confocal Raman microspectroscopy.
abstract: In many biotechnological processes, living microorganisms are used as biocatalysts. Biochemical engineering science is becoming more aware that individual cells of an organism in a process can be fairly inhomogeneous regarding their properties and physiological status. Raman microspectroscopy is a novel approach to characterize such differentiated populations. Cells of the anaerobic bacterium Clostridium beijerinckii were dried on transparent support surfaces. The laser beam of a confocal Raman microscope was focused on individual cells viewed through the objective. Single bacterial cells in size approximately 1 microm and sample mass approximately 1 pg could be analyzed within a few minutes, when placed on a calcium fluoride support and using excitation at 632.8 nm. Spectral features could be attributed to all major cell components. Cells from a morphologically differentiated culture sample showed different compositions, indicating the presence of subpopulations. As a reference, the storage polymer granulose was detected. The multidimensional information in Raman spectra gives a global view on all major components of the cell at once, complementing other more specific information-rich methods for single-cell analysis. The method can be used, for example, to study heterogeneities in a microbial population.
authors: Institute of Analytical Chemistry, Vienna University of Technology, Wien, Austria.
authors: K C
authors: KC
authors: Schuster
authors: I
authors: I
authors: Reese
authors: E
authors: E
authors: Urlaub
authors: J R
authors: JR
authors: Gapes
authors: B
authors: B
authors: Lendl
mesh_terms: D003013:Clostridium / Q000737:chemistry*; D018613:Microscopy, Confocal / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*