Abstract
Toxicological investigations of the impact of inorganic mercury (Hg 2+) and methylmercury (CH 3Hg +) in terms of growth, NH 4 + uptake, in vivo glutamine synthetase (transferase) activity, and regulation of toxicity by Ca 2+, Mg 2+, Cu 2+, and Ni 2+ in the diazotrophic cyanobacterium Nostoc calcicola Bréb. have been completed. Photoautotrophic growth of the cyanobacterium was extremely sensitive to both mercury compounds, CH 3Hg + being 2.5 times more toxic than Hg 2+. Although NH 4 + uptake was 6 times more sensitive than in vivo GS activity against the two mercurials, both processes had a greater susceptibility toward CH 3Hg +. On the basis of K m and V max, it is suggested that both mercury species inhibit such metabolic events noncompetitively. Ca 2+, Mg 2+, Cu 2+, and Ni 2+ did not change the nature of inhibition and effectively antagonized the Hg 2+ and CH 3Hg + toxicities in the sequence Ca 2+ > Mg 2+ ⪡ Cu 2+ > Ni 2+.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call