Zinc toxicity

About: Zinc toxicity is a research topic. Over the lifetime, 727 publications have been published within this topic receiving 34583 citations. The topic is also known as: zinc poisoning.

Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

Abstract: Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

Effect Of Copper And Zinc Toxicity On Physiological And Biochemical Parameters In Vigna Mungo (L.) Hepper

Abstract: The present study aimed at investigating the effects of copper and zinc in Vigna mungo (L.) growth and metabolism. Physiological parameters decrease consequently with increasing copper and zinc concentration in nutrient medium. Copper at 0.2mM concentration led to 32.12% and 47.82% reduction in fresh weight and dry weight respectively whereas, zinc at 1.50mM concentration resulted in 23.83% and 70.56% decrease in fresh weight and dry weight of seedlings with respect to control. The combined effect of copper and zinc on seedling growth was antagonistic at low concentration but showed additive effect at high concentrations. The results demonstrated an increase in DNA content/mg fr. Wt. of seedlings up to 124.45% at 0.2mM Cu + 1.50mM Zn and RNA content was adversely affected in all treatment conditions. Moreover, seedlings exposed to copper and zinc metal ions have shown significant variations in phosphate hydrolysis and mobilization from source to sink and specific activity of acid phosphatase.