Localization and Characterization of Ferritin in Demospongiae: A Possible Role on Spiculogenesis

Marine Drugs

Filipe Natalio¹  Stefanie Wiese¹  Norman Friedrich¹  Peter Werner² 

[1] Institut für Chemie—Anorganische Chemie, Naturwissenschaftliche Fakultät II—Chemie, Physik und Mathematik, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Straße 2, Halle 06120, Germany; E-Mails:;Max-Planck Institute of Microstructure Physics, Weinberg 2, Halle 06120, Germany; E-Mail:

关键词: Suberites domuncula;    primmorphs;    iron;    ferritin;    spiculogenesis;   

DOI  :  10.3390/md12084659

来源: mdpi

【 摘 要 】

Iron, as inorganic ion or as oxide, is widely used by biological systems in a myriad of biological functions (e.g., enzymatic, gene activation and/or regulation). In particular, marine organisms containing silica structures—diatoms and sponges—grow preferentially in the presence of iron. Using primary sponge cell culture from S. domuncula–primmorphs—as an in vitro model to study the Demospongiae spiculogenesis, we found the presence of agglomerates 50 nm in diameter exclusively inside sponge specialized cells called sclerocytes. A clear phase/material separation is observed between the agglomerates and the initial stages of intracellular spicule formation. STEM-HRTEM-EDX analysis of the agglomerates (30–100 nm) showed that they are composed of pseudohexagonal nanoparticles between 5 and 15 nm in size, displaying lattice parameters corresponding to hematite (Fe₂O₃) and mixed iron oxide phases typically attributed to ferritin. Further analysis, using western blotting, inductively coupled plasma mass spectrometry (ICP-MS), sequence alignment analysis, immunostaining and magnetic resonance imaging (MRI), of mature spicule filaments confirm the presence of ferritin within these organic structures. We suggest that S. domuncula can be classified as a dual biomineralizating organism, i.e., within the same cellular structure two distinct biomineralizing processes can occur as a result of the same cellular/metabolic function, spiculogenesis.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.