In situ ATR-IR spectroscopic and electron microscopic analyses of settlement secretions of Undaria pinnatifida kelp spores

Abstract

Knowledge about the settlement of marine organisms on substrates is important for the development of environmentally benign new methods for control of marine biofouling. The adhesion to substrates by spores of Undaria pinnatifida, a kelp species that is invasive to several countries, was studied by scanning electron and transmission electron microscopies (SEM/TEM) as well as by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. The IR spectra showed that adhesive secretion began approximately 15 min after initial settlement and that the adhesive bulk material contained protein and anionic polysaccharides. Energy dispersive X-ray microanalysis of the adhesive identified sulphur and phosphorus as well as calcium and magnesium ions, which facilitate the gelation of the anionic polysaccharides in the sea water. The adhesive may be secreted from Golgi bodies in the spore, which were imaged by TEM of spore thin sections. Additionally, an in situ settlement study on TiO 2 particle film by ATR-IR spectroscopy revealed the presence of phosphorylated moieties directly binding the substrate. The presence of anionic groups dominating the adhesive suggests that inhibition of spore adhesion will be favoured by negatively charged surfaces.

Biochemical analyses of the cement float of the goose barnacleDosima fascicularis– a preliminary study

“…Phosphorus is required as an activation constituent for post-translational modification to form phosphoserine, which plays an important role in the formation of a strong adhesive. This component was also found in the adhesives of caddis flies, mytilid mussels, sandcastle worms and the Cuvierian tubules of the sea cucumber as well as in kelp spore adhesive (Waite & Qin 2001;Zhao et al 2005;Flammang et al 2009;Petrone et al 2011). However, phosphoserines were not found in the adhesive system of barnacles (Kamino 2010) and could not be chemically verified in D. fascicularis.…”

Experimental and computational analysis of a novel flow channel to assess the adhesion strength of sessile marine organisms

“…While all of the surfaces were technically hydrophilic, there was no obvious impact on adhesion strength caused by the relative differences in hydrophobicity of the substrates. Similarities in adhesion strength could be due to the presence of a range of functional groups present in the adhesive material such as glycoproteins and anionic polysaccharides [9,10], allowing interaction with a variety of substrate types. Additionally, the functional groups presented on the surface of the carbohydrate-and protein-based hydrogels, and the polar moieties of PMMA all provide a wealth of locations for adsorption interactions.…”

“…Conventional assays such as tensile, shear and peel tests require the extraction of significant quantities of adhesives, often an unrealistic task for marine bioadhesives owing to their low solubility, fast curing time and small quantities secreted [10]. Ideally, a more practical and low-cost testing method would not require the extraction of adhesive material while being rapid and repeatable.…”

Microscopic and infrared spectroscopic comparison of the underwater adhesives produced by germlings of the brown seaweed speciesDurvillaea antarcticaandHormosira banksii

“…The opportunity offered by ATR-FTIR to study the production of bioadhesives from complex biological species in real time, in vivo and in situ, has been clearly recognized by two recent reviews by Barlow & Wahl [41] and Petrone [42]. For example, ATR-FTIR has been successfully employed to identify the composition of adhesives from a range of biological species including barnacles [43], bacteria [44], diatoms [30], algae [29] and mussels [45].…”

“…Different methods have been used to determine the structural characteristics as well as the chemical composition of biological adhesives from seaweed species, including optical [22,23] and electron microscopy (scanning electron microscopy (SEM) [24][25][26], environmental SEM [27] and transmission electron microscopy [23,28,29]), atomic force microscopy [30][31][32], quartz crystal microbalance with dissipation [33,34], zeta potential [35], energy dispersive X-ray (EDX) [29,30], chemical extraction [36,37], enzymatic assays [38,39], staining and labelling techniques [23,24,40] and infrared spectroscopy [29]. The preparation protocols as well as the testing procedure of most methods require specific conditions often harmful to the biological sample tested and in most cases lead to the death of the specimen, hence the information obtained is usually a snapshot of the sample at a certain point in time.…”