Sodium transport in filamentous nitrogen fixing cyanobacteria.
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Date
1983-09
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Abstract
Two filamentous, nitrogen fixing cyanobacteria were examined for their
salt tolerance and sodium (Na+) transport. Anabaena torulosa, a saline form, grew effi
ciently and fixed nitrogen even at 150 mM salt (NaCl) concentration while, Anabaena
L 31, a fresh water cyanobacterium, failed to grow beyond 35 mM NaCl. Anabaena
torulosa showed a rapidly saturating kinetics of Na+ transport with a high affinity for
Na+ (Km , 0.3 mM). Anabaena L 31 had a much lower affinity for Na+ (Km , 2.8 mM)
than Anabaena torulosa and the pattern of uptake was somewhat different. Both Ana
baena spp. exhibited an active Na+ extrusion which seems to be mediated by a Na+ K+
ATPase and aided by oxidative phosphorylation. Anabaena L 31 was found to retain
much more intracellular Na+ than Anabaena torulosa. The results suggest that the saline
form tolerates high Na+ concentrations by curtailing its influx and also by an efficient
Na+ extrusion, although these alone may not entirely account for its success in saline
environment.
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Keywords
Nitrogen fixation, cyanobacteria, sodium transport, salt tolerance
Citation
Apte Shree Kumar, Thomas Joseph. Sodium transport in filamentous nitrogen fixing cyanobacteria. Journal of Biosciences. 1983 Sept; 5(3): 225-234.