Effect of the polylysine based polymeric polypeptides on the growth and chemotaxis of Tetrahymena pyriformis

Polylysine based branched polypeptides represents a group of biocompatible polymers that could be utilized as macromolecular carriers for drugs, epitopes or reporter molecules. Ten polymers with different character (amino acid composition and charge properties) were prepared: polypeptides with single amino acid in the branches (poly[Lys(X-i)]), X =His, Pro or Glu; and polymers possessing oligo[DL-alanine] side chains only (poly[Lys(DL-Ala(m)) (AK) or with an additional amino acid residue poly[Lys(X-i-DL-Ala(m))] (XAK), where X=Ser (SAK), Thr (TAK), Glu (EAK), acetyl-Glu (Ac-EAK) or succinyl-Glu (Succ-EAK). were investigated. The concentration of these compounds influence the chemotaxis and survival of eukaryotic unicellular model organism, Tetrahymena pyriformis GL. Two types of experiments were performed. First the polymer induced chemoattractant/chemorepellent response of Tetrahymena cells were tested, then chemotactic selection experiments were performed. The chemotactic responses elicited by the polymers were dependent not only on chemical properties (composition, charge and the length of the side chain) of the compounds, but also on their concentration. Based on these results, the polymers were grouped as full-chemoattractant expressing this behavior in the full concentration range investigated (HiK), full-chemorepellent (EiK and Ac-EAK) and partial chemoattractant/chemorepellent with concentration dependent activity (PiK, EAK and Succ-EAK).