Premium
AFM imaging of extracellular polymer release by marine diatom Cylindrotheca closterium (Ehrenberg) Reiman & J.C. Lewin
Author(s) -
Pletikapić Galja,
Radić Tea Mišić,
Zimmermann Amela Hozić,
Svetličić Vesna,
Pfannkuchen Martin,
Marić Daniela,
Godrijan Jelena,
Žutić Vera
Publication year - 2011
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.1114
Subject(s) - diatom , atomic force microscopy , chemistry , extracellular , polymer , biophysics , chemical engineering , materials science , nanotechnology , biology , biochemistry , botany , engineering , organic chemistry
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.