Discussion
Since BMAA may be an environmental factor triggering human neurodegeneration, it is of great importance to elucidate the role of BMAA not only in this human-related context, but also to better comprehend the nature and significance of BMAA in cyanobacteria. To expand our knowledge, we analyzed the physiological and morphological consequences of externally adding BMAA to the nitrogen-fixing cyanobacterium, Nostoc 7120. Together, our data show that this cyanobacterium synthesizes BMAA and, when applied externally, BMAA is taken up in a fast and concentration-dependent manner. The latter observation is in accordance with data for BMAA uptake by the unicellular non-nitrogen-fixing cyanobacterium Synechocystis sp. PCC 6803 [25].