Purification and new biological properties of the slime mold germination inhibitor

We have partially purified a germination inhibitor from the cellular slime mold Dictyostelium purpureum. The molecular weight of the inhibitor could not be determined since we could not exclude the possibility that it interacts with both Bio-Gel and Sephadex. It has an absorption maximum at about 200 nm. At very low concentrations, (which would not be autoinhibitory), the inhibitor preparation temporarily blocks bacterial growth, which was shown to be detrimental to normal development of the cellular slime molds. The inhibitor will also prevent normal aggregation of competent amoebae, but cAMP will reverse this inhibition, as well as the inhibition of germination.