Figure 8.
Iron accumulates, and the Fe2+/Fe3+ ratio increases, in aging worms. (A) XFM images reveal total iron accumulation, but no change in calcium levels, in old worms compared to young worms. Compton scattering provides anatomical structure. (B) Calcein staining is lower in older worms, indicating an increase in labile iron with aging. (C) XANES imaging shows a shift to higher Fe2+/Fe3+ ratios in older worms, as observed by a shift in the Fe K-edge to lower energies. Reproduced from James, S. A.; Roberts, B. R.; Hare, D. J.; de Jonge, M. D.; Birchall, I. E.; Jenkins, N. L.; Cherny, R. A.; Bush, A. I.; McColl, G. Chem. Sci. 2015, 6, 2952–2962 (ref 195) with the permission of The Royal Chemical Society.