Open AccessMapping of nutrient‐induced biochemical changes in living algal cells using synchrotron infrared microspectroscopy
Author(s) -
Heraud Philip,
Wood Bayden R.,
Tobin Mark J.,
Beardall John,
McNaughton Don
Publication year - 2005
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2005.06.021
Subject(s) - absorbance , chloroplast , nucleus , nutrient , biophysics , fourier transform infrared spectroscopy , phospholipid , synchrotron , infrared , biology , chemistry , analytical chemistry (journal) , biochemistry , membrane , chromatography , microbiology and biotechnology , optics , ecology , physics , gene
High quality Fourier transform infrared (FTIR) spectra were acquired from living Micrasterias hardyi cells maintained in an IR transparent flow‐through cell using a FTIR microscope coupled to a synchrotron light source. Spectral maps of living, nutrient‐replete cells showed band intensities consistent with the known location of the nucleus and the chloroplasts. These were very similar to maps acquired from fixed, air‐dried cells. Bands due to lipids were lowest in absorbance in the region of the nucleus and highest in the chloroplast region and this trend was reversed for the absorbance of bands attributed to protein. Spectra acquired in 10 μm steps across living phosphorus‐starved (P‐starved) cells, repeated approximately every 30 min, were consistent over time, and bands correlated well with the known position of the nucleus and the observed chloroplasts, corroborating the observations with replete cells. Experiments in which missing nutrients were re‐supplied to starved cells showed that cells could be maintained in a functional state in the flow‐through cell for up to one day. Nitrogen‐starved cells re‐supplied with N showed an increase in lipid in all positions measured across the cell over a 23 h period of re‐supply, with the largest increases occurring in positions where the chloroplasts were observed. Re‐supply of phosphorus to P‐starved cells produced no changes in bands attributable to lipid or protein. Due to their thin cell body (?12 μm) and large diameter (?300 μm) Micrasterias sp. make an ideal spectroscopic model to study nutrient kinetics in algal cells.