Chemotaxis: The proper physiological response to evaluate phylogeny of signal molecules

In this review we summarize our results gained on the investigations focuse d to characterize ligand and signaling mechanisms required for the chemotax is in the unicellular model Tetrahymena. Our data show that short chain sig nal molecules (amino acids, oligopeptides) are distinguished upon their phy sicochemical characteristics - lipophylicity, residual volumes and statisti cal distribution of side-chain distances (e.g. in proline containing dipept ides), while the vertebrate hormones have also specific attractant or repel lent effects in the model (FSH vs. TSH). Hormonal imprinting developed by p retreatments has also special, signal molecule dependent effect (histamine vs. serotonin). It is shown that "chemotactic selection" of cells, by the n ew probe developed by us is a suitable tool to provide subpopulations posse ssing enhanced chemotactic receptor-effector mechanisms with respect to the selector signal molecules (IL-8, TNF-alpha).