Influence of Iron on Phosphate Metabolism in Cyanobacterium Nostoc Calcicola

The phosphate uptake, alkaline phosphates and total extractable ATP-pool were investigated in a cyanobacterium Nostoc calcicola Breb. under iron stressconditions. The phosphate uptake was maximum in cells raised on 200 μM Fe3+ supplemented Allen and Arnon medium, whereas 150 μM Fe3+ (used for routine culture of Nostoc calcicolas) supported lower phosphate uptake. The cells supplemented with higher iron (300–500 μM Fe3+) depicted reduction in phosphate uptake with maximum reduction observed in 500 μM Fe3+ supplemented cells. Similar results were observed with respect to the effect of iron on alkaline phosphatase activity. The alkaline phosphatase activity was minimum in cells raised on medium having 500 μM Fe3+. Also, the increase in ATPase activity showed corresponding reduction in total extractable ATP-pool. The reduction in ATP-pool is the resultant of lower phosphate level in cells under Fe3+ stress.