Ontological changes in the crystallin composition of the eye lenses of theterritorial damselfish Parma microlepis and their possible effects on trace-metal accumulation
Sg. Dove, Ontological changes in the crystallin composition of the eye lenses of theterritorial damselfish Parma microlepis and their possible effects on trace-metal accumulation, MARINE BIOL, 134(4), 1999, pp. 653-663
The eye lenses of Parma microlepis from the rocky barrens of Sydney (New So
uth Wales, Australia) were found to contain Ba, Hg, Rb, and Sr at concentra
tions above the quantitative detection limits of solution-based inductively
-coupled plasma-mass spectrometry (ICP-MS). Lenses were separated into the
hard central nucleus and the softer surrounding cortex. Nuclei contained lo
wer (equal for Ba) concentrations of these metals. Biochemical analysis of
the protein composition of these lenses revealed differences in the ratio o
f gamma-crystallin to beta-crystallin in the lens nucleus and cortex. These
changes were shown to be attributable both to protein degradation and chan
ges in protein synthesis as fish age. Such changes may lead to the loss of
sequestered metals from older cell layers, or change the affinity of new la
yers for particular trace metals. Differential binding affinities of these
crystallins may, therefore, partially account for trace-metal differences o
bserved in the lens nucleus and cortex.