Marine polysaccharide networks and diatoms at the nanometric scale

• Published in: International Journal of Molecular Sciences Vol. 14; no. 10; pp. 20064 - 20078
• Main Authors: Svetlicic, Vesna, Zutic, Vera, Pletikapic, Galja, Radic, Tea Misic
• Format: Journal Article Book Review
• Language: English
• Published: Switzerland MDPI AG 09.10.2013; Molecular Diversity Preservation International (MDPI)
• Subjects: atomic force microscopy; Bacillariophyceae; Bacteriastrum jadranum; Cell Wall - metabolism; Cylindrotheca closterium; Diatoms - metabolism; extracellular polymeric substance; extracellular polysaccharides; marine diatoms; marine gel network; Microscopy, Atomic Force - methods; northern Adriatic Sea; Polysaccharides - metabolism; Review; Seawater; self assembly; self-organization
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms141020064

Despite many advances in research on photosynthetic carbon fixation in marine diatoms, the biophysical and biochemical mechanisms of extracellular polysaccharide production remain significant challenges to be resolved at the molecular scale in order to proceed toward an understanding of their functions at the cellular level, as well as their interactions and fate in the ocean. This review covers studies of diatom extracellular polysaccharides using atomic force microscopy (AFM) imaging and the quantification of physical forces. Following a brief summary of the basic principle of the AFM experiment and the first AFM studies of diatom extracellular polymeric substance (EPS), we focus on the detection of supramolecular structures in polysaccharide systems produced by marine diatoms. Extracellular polysaccharide fibrils, attached to the diatom cell wall or released into the surrounding seawater, form distinct supramolecular assemblies best described as gel networks. AFM makes characterization of the diatom polysaccharide networks at the micro and nanometric scales and a clear distinction between the self-assembly and self-organization of these complex systems in marine environments possible.