Anomalous settlement behavior ofUlva linzazoospores on cationic oligopeptide surfaces

Abstract

Identification of settlement cues for marine fouling organisms opens up new strategies and methods for biofouling prevention, and enables the development of more effective antifouling materials. To this end, the settlement behaviour of zoospores of the green alga Ulva linza onto cationic oligopeptide self-assembled monolayers (SAMs) has been investigated. The spores interact strongly with lysine- and arginine-rich SAMs, and their settlement appears to be stimulated by these surfaces. Of particular interest is an arginine-rich oligopeptide, which is effective in attracting spores to the surface, but in a way which leaves a large fraction of the settled spores attached to the surface in an anomalous fashion. These 'pseudo-settled' spores are relatively easily detached from the surface and do not undergo the full range of cellular responses associated with normal commitment to settlement. This is a hitherto undocumented mode of settlement, and surface dilution of the arginine-rich peptide with a neutral triglycine peptide demonstrates that both normal and anomalous settlement is proportional to the surface density of the arginine-rich peptide. The settlement experiments are complemented with physical studies of the oligopeptide SAMs, before and after extended immersion in artificial seawater, using infrared spectroscopy, null ellipsometry and contact angle measurements.

Surface Sensing and Settlement Strategies of Marine Biofouling Organisms

“…The Callow group established an assay that allows spores to settle within 45 min to surfaces in order to compare the spore accumulation rate on different surfaces and thus to discriminate their non-fouling potential [62]. A vast number of experiments demonstrated that the settlement kinetics of zoospores of Ulva is affected by a number of physical and chemical surface cues, such as wettability [31,64,67,68], topography [69][70][71][72], and charge [73,74]. Especially self-assembled monolayers (SAM) [75,76] are a versatile class of functional interfaces that are frequently applied in biofouling research, since their mechanical properties are determined by the substrate and thus biological response is solely caused by the surface chemistry.…”

Settlement Behavior of Zoospores of Ulva linza During Surface Selection Studied by Digital Holographic Microscopy

“…Settlement of zoospores of U. linza is 'selective', i.e., the spores respond to physical and chemical surface cues such as wettability [4][5][6][7], topography [8][9][10][11], and charge [12,13], resulting in clear settlement preferences and therefore variable surface colonization by the alga. The question arises as to how spores exert this selectivity-for example; does it involve different behavioral responses in terms of swimming patterns, trajectories and velocities?…”

Hydration and Chain Entanglement Determines the Optimum Thickness of Poly(HEMA-co-PEG10MA) Brushes for Effective Resistance to Settlement and Adhesion of Marine Fouling Organisms

“…7 Understanding how physicochemical properties of surfaces influence the attachment, adhesion and settlement of fouling organisms is essential for the development of new non-toxic antifouling technologies and in designing effective and environmentally benign antifouling coatings. To this end, fouling on well-defined and carefully characterized surface chemistries, such as various oligoethylene glycol selfassembled monolayers (OEG SAMs), [8][9] peptide SAMs, [10][11] saccharide SAMs 12-13 and polymers [14][15][16] and physicochemical properties such as wettability, 9,17 surface energy, [18][19] roughness, 20-21 thickness 22 elastic modulus [22][23] charge 18,24 and several other properties 25 have been studied intensively to understand the role of surface properties on the mechanisms responsible for settlement and adhesion of fouling organisms.…”