Interrelationships between the pathways of inorganic nitrogen assimilation in the cyanobacterium Gloeothece can be described using a mechanistic mathematical model
Article first published online: 17 NOV 2003
Volume 160, Issue 3, pages 545–555, December 2003
How to Cite
Stephens, N., Flynn, K. J. and Gallon, J. R. (2003), Interrelationships between the pathways of inorganic nitrogen assimilation in the cyanobacterium Gloeothece can be described using a mechanistic mathematical model. New Phytologist, 160: 545–555. doi: 10.1046/j.1469-8137.2003.00901.x
- Issue published online: 17 NOV 2003
- Article first published online: 17 NOV 2003
- Received: 29 April 2003 Accepted: 11 August 2003; doi: 10.1046/j.1469-8137.2003.00901.x
- N2 fixation;
- • A mathematical model is described that simulates the major features of the interactions between different nitrogen (N)-sources in the nonheterocystous diazotrophic cyanobacterium Gloeothece.
- • The interaction between ammonium and nitrate is related to the intracellular concentration of glutamine (GLN), which in turn is representative of cellular N-status. Development of nitrogenase activity is related to N-limitation but, once developed, continues for as long as there is sufficient glucan (carbon-reserve) in order to support N2 fixation and the assimilation of the resultant ammonium into amino acids.
- • Nitrogenase activity decreases in response to elevated N-status and also to increased net oxygen evolution, in keeping with biochemical reality. The model describes the diel cycle of C and N2 fixation as seen under alternating 12 h light and 12 h darkness, and also the N2 fixation cycle of about 40 h duration seen in cells cultured in continuous illumination.
- • This model has the potential to be adapted to describe N2 fixation in heterocystous cyanobacterium and in Trichodesmium.