Metal induced non-metallothionein protein in earthworm: A new pathway for cadmium detoxification in chloragogenous tissue

摘要: Earthworms neutralize toxic metals by a small (∼13 kDa) cysteine rich metal binding protein, metallothionein (MT). Although the rate of accumulation and MT expression does not correlate well, reason behind such inconsistency has yet been deciphered. The present investigation clearly demonstrates that some non-MT induced proteins is responsible for incongruity. Applying selective protein isolation techniques in fluorescence tagged cadmium exposed (135 mg/kg) earthworms we were able to purify 150 kDa (MIP) among others. After 60 days exposure earthworm intestines was significant. Immunofluorescence staining followed confocal microscopy exhibited MIP accumulates ingested intestinal region eventually deposits chloragogenous tissue. We determined N-terminal sequence 15 amino acid residues after bioinformatics analysis, it concluded most probably glutamic rich, novel protein. To further validate mechanism, conducted paper chromatography continuous variation experiments which evidenced readily binds acid. finding first in-vivo evidence non-metallothionein environment.