engleski

Supramolecular organization and process of marine gel network formation visualized by atomic force microscopy

The macroscopic marine gel phase appears episodically in the northern Adriatic Sea. The phenomenon manifests itself in rapid production of enormous amounts of gelatinous matter in the water column and on the sea surface. The mechanism of marine gel formation, its stability and the role of gel state in marine ecosystem is becoming a most challenging exercise in converging disciplines of marine chemistry, microbiology and biophysics. Organic fraction of marine gel is mainly composed of polysaccharides, while proteins and lipids are present in small amounts. Although chemical composition of marine gel has been largely studied, determination of the structural parameters remains much more difficult, mainly due to the complexity and heterogeneity. Atomic force microscopy (AFM) has become an important technique for studying biopolymers since it offers high spatial resolution in three dimensions, down to subnanometer level with minimally perturbing sample preparation. We used AFM to study supramolecular organization of marine gel and its polysaccharide fraction at the molecular scale to reveal molecular mechanism of gel formation. Thermal denaturation of marine gel network to single short polymer fibrils upon heating and renaturation of the network after cooling was directly visualized by AFM. These results directly demonstrate the capacity of marine polysaccharides to selfassamble into complex gel network, but also reveal the molecular mechanism of gel formation in the ocean.

supramolecular organization; marine gel network; atomic force microscopy

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