Comparison between hemolymph and tissue ferritin in response to heavy metal feeding in the wax moth Galleria mellonella.

The effects of seven heavy metals on hemolymph and tissue ferritin in Galleria mellonella were examined by western blotting. Hemolymph ferritin was clearly upregulated by Hg, while tissue ferritin was dramatically upregulated by Cd, Cu, Mn, Zn and Ni. The level of hemolymph ferritin for Hg and Cd increased approximately 1.5-fold over normal controls, while the level of tissue ferritin for Cd, Cu, Mn, Zn and Ni increased more than twofold, indicating that the regulation of hemolymph and tissue ferritin differ with the different heavy metals. Compared to normal control insects not fed CdCl₂, ferritin subunit mRNA from the Malpighian tubules, muscle, the gut and the integument was clearly downregulated, as determined by semi-quantitative reverse transcription–polymerase chain reaction, but ferritin subunit mRNA from the silk gland and the fat body did not show any change. These results suggest that in G. mellonella, tissue ferritin is responsible for Cd stress and is thus important for survival of the moth, and that tissue and hemolymph ferritin have different ferritin-inducible mechanisms in response to dietary CdCl₂. [ABSTRACT FROM AUTHOR]