Chemokinesis by tetrahymena in response to bacterial oligopeptides

The ciliate Tetrahymena responds very efficiently by chemoattraction to a group of trichloroacetic acid-soluble oligopeptides isolated from a commercial bioprotein from Methanococcus. When fractionated by reversed phase C18-high-pressure liquid chromatography, this group of very efficient chemoattractants turned out to consist of a heterogeneous group of oligopeptides with molecular weight ranging from 0.2 to 1.5 kDa. The peptides were very rich in the following amino acids: aspartic acid, alanine, glutamic acid, proline, glycine, lysine, and arginine. The term chemokinesis is used throughout to emphasise that chemoattraction does not necessarily include an element of orientation of cells.