Isolation and Characterization of a Substance which Stimulates the Formation of Akinetes in the Cyanobacterium Cylindrospermum licheniforme Kutz.

Abstract

A substance which at low concentration (less than 0.3 .mu.M) stimulated the formation of akinetes in C. licheniforme Kutz. was purified from the centrifugal supernatant fluid of sporulating cultures. High resolution mass spectrometry showed that the chemical formula of the substance is C7H5OSN. Other peaks of high intensity found at m/e values of 123 and 96 in the mass spectrum were produced by loss of CO from the molecular ion, and by additional loss of HCN. Proton nuclear magnetic resonance spectroscopy of the substance showed a complex of peaks in the region of .delta. = 7.19-7.29 ppm. Peaks in the IR absorption specturm were attributable to methylene C.sbd.H bonds and to C.dbd.S and cyclic.sbd.CO.sbd.NH.sbd.groups. The most probable structure consistent with the above findings embodies 2 fused, 5-membered rings, 1 of which is a lactam and the other of which has a thioketone group.