The effect of CuSO4 solutions with Cu2+ ion concentrations equal to 1, 2, 3, 4, and 5 mg/dm3 with the addition of reduced glutathione (GSH) and without it to soil cyanobacteria (CB) of Nostoc paludosum 18 was studied. The duration of exposure of the culture with solutions was 72 hours. During the experiment, the formation of biofilms of the CB from the homogenate was observed, as an indicator of the recovery of the initial population; measured the concentration of dissolved O2 in suspensions of the CB; determined the proportion of CB cells capable of forming formazan from 2,3,5-triphenyltetrazolium chloride as an indicator of the viability of the culture.
Under the action of CuSO4, the culture of the CB violated the ability to form biofilms in solutions with concentrations of Cu2+ 1 mg/dm3 or more without the addition of GSH and at Cu2+ concentrations equal to 3 or more mg/dm3 in the presence of tripeptide. By changing the concentration of dissolved O2, it was not possible to diagnose the toxicity of the solution with a concentration of 1 mg Cu2+ /dm3 throughout the experiment. In a solution with a concentration of 2 mg Cu2+ /dm3, the average degree of toxicity was established after three days of exposure. The medium and low degrees of toxicity were detected in solutions with Cu2+ concentrations of 3–5 mg/dm3 after one day of exposure. With an increase in the concentration of Cu2+, the dehydrogenase activity of the CB decreased by 50% or more compared to the control. Solutions with GSH are less toxic than similar solutions without the addition of GSH. The most acceptable test function for the action of copper(II) ions with their concentrations in the solution exceeding the MPC is the dehydrogenase activity of the N. paludosum CB with a titer of 2•107 cells. /cm3.
Keywords: cyanobacteria, copper (II) ions, glutathione, toxicity
ISSN 1995-4301
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