title: Effect of mercuric ion on the growth, photosynthesis, and nitrogenase activity of Anabaena inaequalis.
abstract: Anabaena inaequalis was sensitive to mercuric ion (Hg2+) in the ppb (nanogram per milliliter) range. Growth was inhibited significantly at concentrations of metal ion as low as 2 ppb, and 100 ppb was required to inhibit photosynthesis and acetylene reduction. Low levels of Hg2+ stimulated acetylene reduction and photosynthesis. The lysis of vegetative cells was the primary action of mercuric ions, resulting in the inhibition of growth, photosynthesis, and nitrogenase activity. There was a linear relationship between numbers of cells and the amount of Hg2+ required to induce culture lysis. Calculated on the basis of equivalent cell numbers, Hg2+ was toxic to A. inaequalis at 0.006, 0.009, and 0.100 micrograms of Hg2+ per 10(5) cells for photosynthesis, growth, and acetylene reduction, respectively.
mesh_terms: D000114:Acetylene / Q000378:metabolism; D000458:Cyanobacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008628:Mercury / Q000494:pharmacology*; D009591:Nitrogenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000187:drug effects*; D014871:Water Microbiology
chemical_list: D009591:Nitrogenase; D008628:Mercury; D000114:Acetylene