The Effect of Ecdysterone on the Cyanobacterium Nostoc 6720

Abstract

The insect hormone ecdysterone stimulated dinitrogen fixation, heterocyst formation, cell size and protein synthesis in suspension cultures of the cyanobacterium Nostoc 6720 within 48 h when added to the culture at concentrations between 10-9 and 10-7 M. In the presence of the hormone the volume of vegetative cells increased by 6-fold and that of heterocysts by nearly twice as compared to untreated controls. All the observed effects were inhibited by the calcium-calmodulin inhibitor, trifluoperazine. Cholesterol used as a null control had no significant effect. © 1992, Walter de Gruyter. All rights reserved.