engleski

Marine vesicles : Adhesion based detection of vesicles-like microparticles in seawater

Abiotic aggregation of biopolymers in seawater has the potential to greatly affect carbon conversion in ocean systems, self-assembly of dissolved biocompounds into vesicles being a significant root by which organic matter may enter the aquatic food chain. Vesicles-like microparticles (VLM) have been for the first time identified in seawater bz amperometric detection of single adhesion events of vesicles at the electrode/seawater interface. In the northern Adriatic Sea concentrations of VLM (sizes≥ 3 μ m) in seawater varied from 105 to 2×107 L. We recorded the pronounced spatial and temporal variability of VLM, depending on the season, depth and trophic gradient. AFM images of submicron particle fractions revealed round patches, 1200 to 50 nm in diameter, of surprisingly uniform height, 1.2 - 1.4 nm, which are typical values reported for polysaccharide single or double molecular chain heights. VLM production recoreded during the diatom bloom experiment shows an extraordinary capacity of extracellular polysaccharides for self-organization, reaching in seawater a level of self-assembly resembling that of organelles (that is, liposomes) in living cells. Because such ordered structures are indicative of directed processes, it cannot be ruled out that MLV catalyse very specific biochemical processes associated with compartmentation, selective transport, and information structuring that are known for biological systems.

marine vesicles; self-assembly; adhesion sensor; AFM of marine particles

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