Position-dependent changes in phycobilisome abundance in multicellular cyanobacterial filaments revealed by Raman spectral analysis

Analysis of fate determination of vegetative cells with reduced phycocyanin content in a multicellular cyanobacterium using Raman microscopy

The one-dimensional multicellular cyanobacterium Anabaena sp. PCC 7120 exhibits two different cell types under nitrogen-deprived conditions. We found that the intensity of the Raman band at 1,629 cm -1 , which is associated with phycocyanin, was higher in undifferentiated cells (vegetative cells) than in differentiated cells (heterocysts). We observed cells whose band intensity at 1,629 cm -1 was statistically lower than that of vegetative cells, and named them "proheterocysts". We found that proheterocysts did not necessarily differentiate, and could divide or revert to being vegetative cells, as defined by having a higher band intensity at 1,629 cm -1 .