Interactions of Ulva linza zoospores with arginine-rich oligopeptides
(English)Manuscript (Other academic)
We recently reported on the strong interactions of Ulva linza zoospores with an arginine-rich oligopeptide self-assembled monolayer (SAM) [Biofouling 24:303-312 (2008)], where the arginine-rich peptide induced not only very high settlement but also a form of abnormal settlement, or “pseudo-settlement”, where spores do not go through the normal behaviours of surface exploration, adhesive exocytosis and flagella loss. Further, it was demonstrated that both the total settlement and the fraction of anomalously settled spores were related to the surface density of the arginine-rich peptide.Here we present a further investigation of the interactions of Ulva zoospores with a set of oligomeric de novo designed arginine-rich peptides, specifically aimed to test the effect of peptide primary structure on the interaction. Via variations in the peptide length and by permutations in the amino acid sequences, we gain further insight into the spore-surface interactions. The interpretation of the biological assays is supported by physicochemical characterization of the SAMs using infrared spectroscopy, ellipsometry and contact angle measurements. Results confirm the importance of arginine residues for the anomalous settlement, and we found that settlement is modulated by variations in the peptide primary structure. To elucidate the causes of the anomalous settlement and the possible relation to peptide-membrane interactions, we also compared the settlement of the “naked” Ulva zoospores (which lack a cell wall), with the settlement of Navicula diatoms (which are surrounded by a silica shell), onto the peptide SAMs. Cationic SAMs do not particularly affect adhesion or viability of diatoms, suggesting that the effect of the peptides on Ulva is mediated via specific peptide-membrane interactions.
IdentifiersURN: urn:nbn:se:liu:diva-15020OAI: oai:DiVA.org:liu-15020DiVA: diva2:37625