Chemoattraction of a bactivorous ciliate to bacteria surface compounds

The locomotory response to cell surface compounds extracted from two prey species, Vibrio natriegens and Vibrio neries , was tested for a bacterivorous ciliate, Pseudocohnilembus marinus . Chemoattraction of the ciliate to the surface compounds stabilized in agarose baits was not equal for the two prey species. Fractionation of the extracts suggested the attractive substance was a high molecular weight compound. The expression of the differential response was dependent on the physiological condition and prior prey species exposure of the ciliate test population. The recognition and response to material normally found on the surface of prey cells supports evidence for the involvement of chemical sensing of gradients of prey particles and dissolved compounds of prey origin in the natural swimming behavior of bacterivorous ciliates. The prey species-specific reactions and influence of ciliate physiological state on chemosensory response suggest ciliate-bacteria interactions may be more complex than preciously assumed.