Phosphate transport and arsenate resistance in the cyanobacterium Anabaena variabilis.
Cells of the cyanobacterium Anabaena variabilis starved for phosphate for 3 days took up phosphate at about 100 times the rate of unstarved cells. Kinetic data suggested that a new transport system had been induced by starvation for phosphate. The inducible phosphate transport system was quickly repressed by addition of Pi. Phosphate-starved cells were more sensitive to the toxic effects of arsenate than were unstarved cells, but phosphate could alleviate some of the toxicity. Arsenate was a noncompetitive inhibitor of phosphate transport; however, the apparent Ki values were high, particularly for phosphate-replete cells. Preincubation of phosphate-starved cells with arsenate caused subsequent inhibition of phosphate transport, suggesting that intracellular arsenate inhibited phosphate transport. This effect was not seen in phosphate-replete cells.
D001149:Arsenates / Q000633:toxicity*; D001151:Arsenic / Q000633:toxicity*; D001692:Biological Transport; D000458:Cyanobacteria / Q000187:drug effects / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism*
D001149:Arsenates; D010710:Phosphates; D001151:Arsenic