Unicellular cyanobacteria with a new mode of life: the lack of photosynthetic oxygen evolution allows nitrogen fixation to proceed.

Some unicellular N(2)-fixing cyanobacteria have recently been found to lack a functional photosystem II of photosynthesis. Such organisms, provisionally termed UCYN-A, of the oceanic picoplanktion are major contributors to the global marine N-input by N(2)-fixation. Since their photosystem II is inactive, they can perform N(2)-fixation during the day. UCYN-A organisms cannot be cultivated as yet. Their genomic analysis indicates that they lack genes coding for enzymes of the Calvin cycle, the tricarboxylic acid cycle and for the biosynthesis of several amino acids. The carbon source in the ocean that allows them to thrive in such high abundance has not been identified. Their genomic analysis implies that they metabolize...

Categories: Publication; Types: Citation, Journal Citation; Tags: Archives of Microbiology, Chlamydobotrys, Marine nitrogen-fixing cyanobacteria, Rhopalodia gibba, Spheroid bodies of diatoms, All tags... Springer Berlin / Heidelberg, Symbiotic nitrogen fixation, UCYN-A cyanobacteria, Unicellular cyanobacteria without photosystem II, Fewer tags