African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12254

Full Length Research Paper

Phosphate uptake kinetics and its regulation in N2-fixing cyanobacterium Anabaena oryzae Fritsch under salt stress

Santosh Kumar Singh1*, Vandana Pandey2, and Kapil Deo Pandey3
1Centre of Experimental Medicine and Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221 005, India. 2Department of Botany, Agrasen Kanya Autonomous Post Graduate College, Maidagin, Varanasi - 221 001, India. 3Algal Research Laboratory, Department of Botany, Banaras Hindu University, Varanasi-221 005, India.
Email: [email protected]

  •  Accepted: 13 August 2007
  •  Published: 18 October 2007


Phosphorous (P) starved cells of the cyanobacterium Anabaena oryzae showed higher phosphate uptake rates than P-sufficient cells. The P-uptake obeyed saturation kinetics. The Km value for P-deficient cells was lower (54.34 mM) than P-sufficient cells (82.64mM) while Vmax was higher in P-deficient and lower in P-sufficient cells. Salinity (NaCl) stimulated phosphate uptake significantly in the cyanobacterium which is followed by greater amount of P-accumulation in the form of polyphosphate bodies. Inhibition of P-uptake in P-deficient cells was 45% in dark grown compared to light grown cells. P-uptake was inhibited 52 and 85% in culture treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU; 10 mM) and carbonyl cyanide m-chloro phenylhydrazone (CCCP; 100 mM), respectively, suggesting that energy for uptake could be derived from oxidative phosphorylation and photophosphorelation.


Key words: Anabaena oryzae, metabolic inhibitors, phosphorus-uptake, salinity.