Abstract
The acidophilic and thermophilic unicellular red alga, Cyanidium caldarium (Tilden) Geitler, is widely distributed in acidic hot springs. Observation by transmission electron microscopy (TEM) showed that algae grown in Allen's medium contained electron-dense bodies with diameters from 100 to 200 nm. Electron dispersive x-ray analysis indicated that the electron-dense bodies contained high levels of iron, phosphorous, and oxygen; P/Fe ratios were from 1.3 to 2.0. The electron spin resonance (ESR) spectrum of the intact C. caldarium cells showed an isotropic signal at a g value of 2.00. Density-gradient centrifugation of the cell lysate yielded a fraction that included substances showing the isotropic ESR signal. EDTA treatment of this fraction reduced the ESR signal intensity, whereas it increased a signal that is typical of Fe(III)-EDTA. The fact that the isotropic signal dominates the ESR spectrum, together with a previous finding that iron is confined to the electron-dense bodies, led us to conclude that iron in the electron-dense bodies accounts for the isotropic ESR signal. Since the intensity of the ESR signal depends on the amount of iron in the cells, the electron-dense bodies are probably iron storage sites.
Similar content being viewed by others
References
Allen MB. 1959 Studies with Cyanidium caldarium, an anomalously pigmented chlorophyte. Archiv Mikrobiol 32, 270-277.
Archibald FS, Fridovich I. 1982 Investigations of the state of the manganese in Lactobacillus plantarum. Arch Biochem Biophys 215, 589-596.
Buttrose MS. 1978 Manganese and iron in globoid crystals of protein bodies from Avena and Casuarina. Aust J Plant Physiol 5, 631-639.
Dunn T, Gable K, Beeler T. 1994 Regulation of cellular Ca2+ by yeast vacuoles. J Biol Chem 269, 7273-7278.
Gonzalez H, Jensen TE. 1998 Nickel sequestering by polyphosphate bodies in Staphylococcus aureus. Microbios 93, 179-185.
Klausner RD, Rouault TA, Harford JB. 1993 Regulating the fate of mRNA: The control of cellular iron metabolism. Cell 72, 19-28.
Lu HK, Huang CM, Li CW. 1995 Translocation of ferritin and biomineralization of goethite in the radula of the limpet Cellana toreuma reeve. Exp Cell Res 219, 197-145.
Mann S, Bannister JV, Williams RJP. 1986 Structure and composition of ferritin cores isolated from human spleen, limpet (Patella vulgata) hemolymph and bacterial (Pseudomonas aeruginosa) cells. J Mol Biol 188, 225-232.
Nagasaka S, Nishizawa KN, Negishi T, Satake K, Mori S, Yoshimura E. 2002 Novel iron storage particles may play a role in aluminum tolerance of Cyanidium caldarium. Planta 215, 399-404.
Nagashima H, Fukuda I. 1981 Morphological properties of Cyanidium caldarium and related algae in Japan. Jap J Phycol (Sôrui) 29, 237-242.
Seckbach J. 1982. Ferreting out the secrets of plant ferritin-A review. J Plant Nutr 5, 369-394.
Seckbach J. 1994 The first eukaryotic cells-acid hot-spring algae. J Biol Physics 20, 335-345.
Theil EC. 1994 Iron regulatory elements (IREs): A family of mRNA non-coding sequences. Biochem J 304, 1-11.
Treffry A, Harrison PM, Cleton MI, DeBruijn WC, Mann S. 1987 A note on the composition and properties of ferritin iron cores. J Inorg Biochem 31, 1-6.
van der Mark F, Bienfait F, van der Ende H. 1983 Variable amounts of translatable ferritin mRNA in bean leaves with various iron contents. Biochem Biophys Res Comm 115, 463-469.
van Veen HW, Abee T, Kortstee GJJ, Koning WN, Zehnder AJB. 1993 Mechanism and energetics of the secondary phosphate transport system of Acinetobacter johnsonii 210A. J Biol Chem 268, 19377-19383.
Wade VJ, Treffry A, Laulhere JP, Bauminger ER, Cleton MI, Mann S, Briat JF, Harrison PM. 1993 Structure and composition of ferritin cores from pea seed (Pisum sativum). Biochem Biophys Acta 1161, 91-96.
Watt GD, Frankel RB, Papaefthymiou GC, Spartalian K, Stiefel EI. 1986 Redox properties and Mössbauer spectroscopy of Azotobacter vinelandii bacterioferritin. Biochemistry 25, 4330-4336.
Weil JA, Bolton JR, Wertz JE. 1994 Electron Paramagnetic Resonance. New York: John Wiley & Sons, Inc. 492-497.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nagasaka, S., Nishizawa, N.K., Watanabe, T. et al. Evidence that electron-dense bodies in Cyanidium caldarium have an iron-storage role. Biometals 16, 465–470 (2003). https://doi.org/10.1023/A:1022563600525
Issue Date:
DOI: https://doi.org/10.1023/A:1022563600525