Synchrotron X-rays reveal the modes of Fe binding and trace metal storage in the brown algae Laminaria digitata and Ectocarpus siliculosus

0583895 - BC 2024 RIV US eng J - Článek v odborném periodiku
Mijovilovich, Ana - Cloetens, P. - Lanzirotti, A. - Newville, M. - Wellenreuther, G. - Kumari, P. - Katsaros, C. - Carrano, C. J. - Küpper, Hendrik - Kupper, F. C.
Synchrotron X-rays reveal the modes of Fe binding and trace metal storage in the brown algae Laminaria digitata and Ectocarpus siliculosus.
Metallomics. Roč. 15, č. 10 (2023), č. článku mfad058. ISSN 1756-5901. E-ISSN 1756-591X
Grant CEP: GA MŠMT EF15_003/0000336
Institucionální podpora: RVO:60077344
Klíčová slova: algae * iron * strontium * tomography * xanes * ferritin
Obor OECD: Biophysics
Impakt faktor: 3.4, rok: 2022
Způsob publikování: Open access
https://academic.oup.com/metallomics/article/15/10/mfad058/7281006?login=true

Iron is accumulated symplastically in kelp in a non-ferritin core that seems to be a general feature of brown algae. Microprobe studies show that Fe binding depends on tissue type.The sea is generally an iron-poor environment and brown algae were recognized in recent years for having a unique, ferritin-free iron storage system. Kelp (Laminaria digitata) and the filamentous brown alga Ectocarpus siliculosus were investigated using X-ray microprobe imaging and nanoprobe X-ray fluorescence tomography to explore the localization of iron, arsenic, strontium, and zinc, and micro-X-ray absorption near-edge structure (mu XANES) to study Fe binding. Fe distribution in frozen hydrated environmental samples of both algae shows higher accumulation in the cortex with symplastic subcellular localization. This should be seen in the context of recent ultrastructural insight by cryofixation-freeze substitution that found a new type of cisternae that may have a storage function but differs from the apoplastic Fe accumulation found by conventional chemical fixation. Zn distribution co-localizes with Fe in E. siliculosus, whereas it is chiefly located in the L. digitata medulla, which is similar to As and Sr. Both As and Sr are mostly found at the cell wall of both algae. XANES spectra indicate that Fe in L. digitata is stored in a mineral non-ferritin core, due to the lack of ferritin-encoding genes. We show that the L. digitata cortex contains mostly a ferritin-like mineral, while the meristoderm may include an additional component.
Trvalý link: https://hdl.handle.net/11104/0352325