Effects of cyclic nucleotides on morphogenesis in Nostoc muscorum

Abstract

The filamentous cyanophyte Nostoc muscorum A grew aseriately in light in a mineral salts (sugar-free) culture medium supplemented with adenosine 3':5'-cyclic-monophosphate or N⁶, O²-dibutyryl adenosine 3':5'-cyclic-monophosphate (1 mM). The aseriate morphology thus formed in the light on the 10th day following inoculation was similar to that formed in the dark after 20-30 days growth in cAMP-free medium containing glucose or sucrose. Inoculum previously grown in sucrose- or glucose-containing medium displayed aseriate morphology with lesser proliferation of coccoid cells as compared to inoculum grown in the absence of glucose or sucrose. cGMP, ADP, AMP and inhibitors of phosphodiesterase (theophylline and caffeine) did not have any effect on the persistence of aseriate morphology. However they stimulated cell division at the aseriate stage and delayed the release of hormogonia.