Browsing by Author "Jeet Bahadur Singh"

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Effects of Amino Acids, Carbohydrates and Phosphorus Sources on Growth and Alkaline Phosphatase Activity of the Marine Cyanobacterium Anabaena sp. Strain CA
(1997) Jeet Bahadur Singh; Deepak Vyas; Har Darshan Kumar
Alkaline phosphatase (APase) was found to be inducible in Anabaena sp. strain CA. Growth was less than control in presence of most amino acids except glycine and serine, but most amino acids enhanced APase activity. Highest APase activity was recorded in tyrosine supplemented culture followed by hydroxyproline, cystein, valine and glutamic acid. Threonine supplemented material showed lowest APase level (1.8 nmol/mg protein/min). Lactose, glucose, sodium pyruvate and succinate stimulated growth but not APase activity. APase activity was high in the presence of sucrose, mellibiose, mannitol, arabinose, maltose and sorbose, even though the growth in these supplements was less than in control. Organic phosphate sources supported good growth of the organism. Best growth occurred in presence of inorganic phosphate, adenosine diphosphate, fructose 1,6-diphosphate or ribulose 1,5-diphosphate, followed by other phosphorus sources tested. APase activity in presence of any of the organic phosphate sources was 3 to 5 fold low as compared to phosphate limited culture. Also, there was no APase activity in cultures grown on inorganic phosphate. These data indicate that most amino acids and a few carbohydrates (sucrose, mellibiose, arabinose and sorbose) are suitable for APase production. Lactose, glucose, pyruvate or succinate may be used as a carbon source during photoheterotrophic growth of the cyanobacterium. Glycine and serine are preferred nitrogen sources for its growth. Phosphate repressible APase activity has been found in Anabaena sp. strain CA.
Response of the cyanobacterium nostoc muscorum to chromium and lead: The effect on phosphorus metabolism
(1993) Jeet Bahadur Singh; Smeo Mohan Prasad; Lal Chand Rai; Har Darshan Kumar
Significant amelioration of Cr and Pb toxicity was observed in Nostoc muscorum at high concentrations of phosphate. The effect of Cr and Pb on growth, photosynthetic oxygen evolution, carbon and nitrogen fixation of N. muscorum was less in cultures pre- and post-treated with high (80 μM) Phosphate concentration than in those treated with a lower (20 μM) Orthophosphate concentration. The uptake of Cr and Pb in the cyanobac-terial cells was not affected by phosphate concentration. Likewise phosphate uptake was not disturbed either by Cr or Pb. A rapid accumulation of polyphosphate bodies in the cells treated with Cr and Pb indicates that uptake and accumulation of phosphate was not inhibited. N. muscorum cells exposed to both the metals registered a notable decrease in the breakdown of polyphosphate bodies and acid and alkaline phosphatase activities. Cr and Pb competitively inhibited the activity of partially purified acid and alkaline phosphatases. It is concluded that Cr and Pb affect intracellular phosphate metabolism rather than the uptake and incorporation of phosphate in N. muscorum. © 1993, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.