Nitrate reductase activty: a solution to nitrate problems tested in free and immobilized algal cells in presence of heavy metals

Every organism has different potential to accumulate NO3- from the environment. Nitrate reduction processes are perhaps most significant in maintaining water quality by alteration of nitrate to nitrite. A comparative study between the nitrate reductase NR activity of green and blue green algae in presence of heavy metals is being conducted to present a situation where nitrate reductase process may be affected in presence of heavy metals. Metals interacted negatively with the nitrate reductase activity of a blue green alga, Anacystis nidulans and green algae, Chlorella vulgaris in both free and immobilized state. The activity was more repressed in C. vulgaris in presence of Ni compared to Zn and Cd. However, Cd was more toxic to NR activity in A. nidulans [free state]. Metal dependent variation between free and immobilized cells were found to be significant [P< 0.01] however, the concentration dependent pattern in the activity between free and immobilized state was non significant in both the test organisms. C.vulgaris is more efficient in conversion of nitrate to nitrite compared to A.nidulans in presence of heavy metals

Interactive effects of salinity with some hormonal and non-hormonal growth substances on chlorella fusca II- nitrate reductase activity, proline and protein contents

Sodium chloride at 320 mM increased proline content but suppressed protein accumulation and nitrate reductase activity of Chlorella fusca. 10-5 M, 10-6 M of GA3, IAA, kinetin and thiourea increased protein, proline and NRA of the algal cells relevant to control. The four used growth substances reacted in antagonism with NaCl in the same parameters. In counteracting, the adverse effect of salinity, IAA was more effective, while thiourea was the least effective one