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Interrelationships between the pathways of inorganic nitrogen assimilation in the cyanobacterium Gloeothece can be described using a mechanistic mathematical model
Author(s) -
Stephens Nicholas,
Flynn Kevin J.,
Gallon John R.
Publication year - 2003
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00901.x
Subject(s) - nitrogenase , trichodesmium , cyanobacteria , nitrogen fixation , diel vertical migration , diazotroph , ammonium , assimilation (phonology) , carbon fixation , nitrogen cycle , nitrogen , photosynthesis , nitrate , nitrogen assimilation , biophysics , biology , darkness , botany , chemistry , bacteria , ecology , linguistics , philosophy , organic chemistry , genetics
Summary• 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 N 2 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 N 2 fixation as seen under alternating 12 h light and 12 h darkness, and also the N 2 fixation cycle of about 40 h duration seen in cells cultured in continuous illumination. • This model has the potential to be adapted to describe N 2 fixation in heterocystous cyanobacterium and in Trichodesmium .