The effect of shikimate onNostoc linckia.

Growth, heterocyst frequency and nitrogenase-catalysed hydrogen evolution, but not nitrogenase activity, hydrogen uptake and photosynthetic O2 evolution activities of the cyanobacteriumNostoc linckia, were significantly affected by shikimic acid (up to 10 μg/ml). Exposure ofN. linckia to shikimic acid at 50 μg/ml for 24 h caused fragmentation of filaments into 10- to 15-celled trichomes.