Paul J. Dierickx
Inessa Remez, Pauls Andersons and Hackel Veksler
Environmental mercury and mercury compound contamination has increased dramatically since the industrial revolution. This paper describes the toxic effects of mercury on a culture of hybridoma TA7 cells, which produce antibodies against the A-subunit of viskumin. Cells were cultivated on 96-well flat-bottomed plates with RPMI-1640 medium supplemented with 10% fetal calf serum at 37°C in 5% CO2/95% air. The cells were exposed to 0.1nM/l–10μM/l Hg2(NO3)2.2H2O (mercury nitrate) during the exponential growth phase. Toxicity was assessed by using the colorimetric MTT (tetrazolium) assay after exposure for 48 hours. Cell growth and cell survival were evaluated by using percentage indices of cellular content in exposed cells when compared to non-exposed control cells. The concentrations of the noeffect level, the lowest observed effect level and the the highest toxic effect level were registered. The toxic effects of the mercury compound on the hybridoma cells occurred between 0.1μM/l and 10μM/l.
A Comparative Study of the Toxicity of Mercury Dichloride and Methylmercury, Assayed by the Frog Embryo Teratogenesis Assay–Xenopus (FETAX)
Mariangela Prati, Rosalba Gornati, Patrizia Boracchi, Elia Biganzoli, Salvador Fortaner, Romano Pietra, Enrico Sabbioni and Giovanni Bernardini
The Frog Embryo Teratogenesis Assay–Xenopus (FETAX) is a powerful and flexible bioassay that makes use of the embryos of the anuran amphibian Xenopus laevis. The FETAX can detect xenobiotics that affect embryonic development, when mortality, teratogenicity and growth inhibition are used as endpoints. The FETAX was used to compare the embryotoxic and teratogenic potentials of two chemical species of mercury: inorganic mercury(II) chloride (HgCl2) and organic methylmercury chloride (MeHgCl). MeHgCl, with an estimated median lethal concentration [LC50] of 0.313μM and a median teratogenic concentration [TC50] of 0.236μM, showed a higher toxicity than HgCl2, with estimated LC50 and TC50 values of 0.601μM and 0.513μM, respectively. On the basis of these results, HgCl2 and MeHgCl can be classified as “slightly teratogenic compounds”, as the ratio of LC50/TC50 is less than 1.5. There was a significant deviation from the commonly described monotonic behaviour of the concentration–response curves, suggesting a hormetic effect of both species of mercury. Uptake experiments, followed by neutron activation analysis, showed a higher incorporation of mercury in embryos exposed to MeHgCl compared with those exposed to HgCl2. Interestingly, Hg-exposed embryos showed a higher content of selenium and zinc than did control embryos.