The protection of invertebrates, fish, and vascular plants against inorganic mercury poisoning by sulfur and selenium derivatives.

Protection of organisms against mercury (Hg) poisoning is most commonly associated with the antagonistic effects of selenium (Se)-compounds against mercury alkyls in higher animals. This study shows that there is no consistent difference among Periodic Group VIA derivatives including S(IV), S(II) organic, Se (IV), Se (II) organic, possibly Se VI, as well and Te (IV) in their ability to protect against mercury poisoning. The organisms used in assays were: Coleus explants (leaf abscission); turnip (germination); pea (growth inhibition and Hg uptake); a planarian (regeneration); the brineshrimp (excystment, phototaxy); the mealworm larva Tenebrio (metamorphosis) and the fish "tilapia" (survival, Hg uptake). Thiamine was the most effective of the Group VIA derivatives against the widest spectrum of organisms and test systems. In planarian regeneration, it was active where S and Se compounds failed. The most unexpected observation was the hastening of insect metamorphosis by HgCl2 and the enhancement of that effect by thiamine.