The effects of nitrogen deficiency on pigments and lipids of cyanobacteria.

In contrast to what happens in higher plants and eukaryotic algae, a nitrogen deficiency during growth causes a change in pigment composition but no significant changes in whole cell lipid and fatty acid composition of the two Cyanobacteria, Pseudanabaena sp. (strain M2) and Oscillatoria splendida (strain L3). Nitrogen deficiency does not affect the cellular content in chlorophyll a, but it causes a selective loss in phycobiliproteins; carotenoid content increases with phycocyanin depletion. The major cellular lipids in both Cyanobacteria studied are monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol. The fatty acid composition is particularly interesting as both these filamentous Oscillatoriaceae show important contents in alpha- and gamma-linolenic (18:3) and parinaric (18:4) acids. This seems to be very unusual in Cyanobacteria.