Investigation of Microorganisms at the Single-Cell Level using Raman Microspectroscopy and Nanometer-scale Secondary Ion Mass Spectrometry
Stephanie A. Eichorst and Dagmar Woebken
from: Applications of Molecular Microbiological Methods (Edited by: Torben L. Skovhus, Sean M. Caffrey and Casey R.J. Hubert). Caister Academic Press, U.K. (2014)
The field of single-cell ecophysiology has taken an exciting turn with the introduction of two powerful techniques, nanometer-scale secondary ion mass spectrometry (NanoSIMS) and Raman microspectroscopy. These techniques allow the investigation of microorganisms and their associated activity at the single-cell level. When combined with stable isotope tracers and/or identification of the targeted cell using fluorescence in situ hybridization (FISH), they have the potential to link the identity of a microorganism with its in situ activity. Raman microspectroscopy detects the scattering of light due to interaction with chemical bonds of cell constituents thereby providing compound specific information, which can also be used for bacterial identification. NanoSIMS permits highly sensitive analysis of multiple elements or isotopes with sub-micrometer spatial resolution, allowing the measurements of microbial activity when used in stable-isotope tracer experiments. In this chapter we present the principle for each technique, discuss their strengths and weaknesses, and document their applicability with particular emphasis on microbial ecology research. The integration of these single-cell techniques in the field of microbial ecology will improve our understanding of the ecophysiology of (novel) microorganisms across a multitude of environments read more ...