Novel iron-storage particles may play a role in aluminum tolerance of Cyanidium caldarium.
Cyanidium caldarium (Tilden) Geitler, a unicellular red alga, has extraordinarily high aluminum (Al) tolerance. Algal cells cultured in the presence or absence of Al were subjected to transmission electron microscopy and energy dispersive X-ray analysis. Substantial changes to the thylakoid lumens were observed for the algal cells cultured in medium containing 200 mM Al, while other organelles were largely unaffected. Several spherical electron-dense bodies were found in the cytoplasm near the nucleus of both of the control and Al-treated cells. Although high levels of Fe and P were found in the bodies of control cells, immunocytochemical and morphological analysis data did not match the criteria established for Fe-accumulating substances like ferritin and phytate. In addition to these elements, Al was found in the bodies of the Al-treated cells. These results suggest that the electron-dense bodies function as an Fe-storage site under normal culture conditions, and that sequestration of Al in these bodies contributes to the high Al tolerance exhibited by C. caldarium.
Nagasaka
Seiji
S
Department of Applied Biological Chemistry, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Nishizawa
Naoko K
NK
Negishi
Takashi
T
Satake
Kenichi
K
Mori
Satoshi
S
Yoshimura
Etsuro
E
D000535:Aluminum / Q000493:pharmacokinetics*; D002478:Cells, Cultured; D004361:Drug Tolerance; D007501:Iron / Q000378:metabolism*; D008854:Microscopy, Electron; D000461:Rhodophyta / Q000502:physiology* / Q000648:ultrastructure
D000535:Aluminum; D007501:Iron