Characterization of Tissue‐Ferritin Purified from Wax Moth, Galleria mellonella

Abstract

Tissue‐ferritin was homogeneously purified from the hemolymph‐free whole body of Galleria mellonella larvae. Tissue‐ferritin was composed of four subunits, 26, 30, 32 and 34 kDa. The 34 kDa subunit among them was specifically found in tissue ferritin while its N‐terminal sequence of 19 amino acid residues was identical to that of 32 kDa hemolymph‐ferritin subunit. It was observed that the 32 and 34 kDa subunit of tissue‐ferritin were glycosylated like 32 kDa subunit of hemolymph‐ferritin. It suggests that the 34 kDa subunit is an isoform of 32kDa ferritin subunit according post‐transcriptional modification. By semi quantitative RT‐PCR, the distribution of 32 kDa ferritin subunit mRNA was observed in fat body, Malpighian tubules, integument, and muscle, but found in a very small amount in silk gland or not found in gut. On the other hand, 26 kDa subunit mRNA was found in all organs tested although it was in a small quantity found in gut and silk gland. By dietary Hg treatment, 34 kDa subunit of tissue‐ferritin was clearly up‐regulated.

Iron Acquisition in Bacillus cereus: The Roles of IlsA and Bacillibactin in Exogenous Ferritin Iron Mobilization

“…High amounts of ferritin are found in the insect hemocoel (mg/L quantity) compared to the low level of vertebrate plasma ferritin (µg/L quantity) [4] , [48] . Thus, insect ferritins represent an easily accessible iron-concentrated source for extracellular pathogens such as B. cereus and have been purified from the tissues and the hemolymph of the greater wax moth Galleria mellonella [49] , [50] , a very useful model to study bacterial pathogenesis [51] . While earlier studies have reported on the importance of IlsA in growth and survival of B. cereus in G. mellonella [14] , [33] , our current data suggest that bacillibactin acts in unison with IlsA in ferritin utilization.…”