This article is published in Journal of Molecular Recognition as a focus on AFM on Life Sciences and Medicine, edited by Jean-Luc Pellequer and Pierre Parot (CEA Marcoule, Life Science Division, Bagnols sur Cèze, France).
AFM imaging of extracellular polymer release by marine diatom Cylindrotheca closterium (Ehrenberg) Reiman & J.C. Lewin†
Version of Record online: 4 APR 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Journal of Molecular Recognition
Special Issue: AFM on Life Sciences and Medicine
Volume 24, Issue 3, pages 436–445, May/June 2011
How to Cite
Pletikapić, G., Radić, T. M., Zimmermann, A. H., Svetličić, V., Pfannkuchen, M., Marić, D., Godrijan, J. and Žutić, V. (2011), AFM imaging of extracellular polymer release by marine diatom Cylindrotheca closterium (Ehrenberg) Reiman & J.C. Lewin. J. Mol. Recognit., 24: 436–445. doi: 10.1002/jmr.1114
- Issue online: 1 APR 2011
- Version of Record online: 4 APR 2011
- Manuscript Accepted: 25 OCT 2010
- Manuscript Revised: 28 SEP 2010
- Manuscript Received: 20 MAY 2010
- marine diatom;
- Cylindrotheca closterium;
- Ceratoneis closterium;
- extracellular polymer substance;
- atomic force microscopy;
- Adriatic Sea
Extracellular polysaccharide production by marine diatoms is a significant route by which photosynthetically produced organic carbon enters the trophic web and may influence the physical environment in the sea. This study highlights the capacity of atomic force microscopy (AFM) for investigating diatom extracellular polysaccharides with a subnanometer resolution. Here we address a ubiquitous marine diatom Cylindrotheca closterium, isolated from the northern Adriatic Sea, and its extracellular polymeric substance (EPS) at a single cell level. We applied a simple procedure for AFM imaging of diatom cells on mica under ambient conditions (in air) to achieve visualization of their EPS with molecular resolution. The EPS represents a web of polysaccharide fibrils with two types of cross-linking: fibrils association forming junction zones and fibril–globule interconnections with globules connecting two or more fibrils. The fibril heights were 0.4–2.6 nm while globules height was in the range of 3–12 nm. Polymer networks of native gel samples from the Northern Adriatic and the network formed by polysaccharides extracted from the C. closterium culture share the same features regarding the fibril heights, pore openings and the mode of fibril association, proving that the macroscopic gel phase in the Northern Adriatic can be formed directly by the self-assembly of diatom released polysaccharide fibrils. Copyright © 2011 John Wiley & Sons, Ltd.