Synchrotron FTIR as a tool for studying populations and individual living cells of green algae

Fourier transform infrared (FTIR) spectromicroscopy was used to study individual living cells of three closely-related species of the green algae Chlamydomonas. This study differentiated these three species based on differences in lipid and protein profiles, as well explored sources of variation in our measurements. Significant spectral variation was observed between individual cells within a single culture, as well as between control cultures of a species obtained on different days. Despite this, we were able to differentiate between the three close-related species. Differences in the spectra were confirmed using principal component analysis. Understanding the interplay of underlying variation and the degree of induced spectral differences is essential for the deployment of FTIR measurements in both bulk cultures and for individual living cells.