Abstract
The filamentous cyanobacterium Anabaena sp. PCC 7120 develops heterocysts in response to deprivation of fixed nitrogen. Heterocyst is capable of fixing nitrogen. Various genes encoding the transcription factors regulating the differentiation and the enzymes involved in heterocyst envelope formation have been identified. A regular pattern has been observed for heterosyst spacing. However, no continuous observation of a single filament was attempted during the heterocyst diffentiation. In the present study, we observed single filaments of Anabaena continuously, and recorded the cell shape and fluorescence of cells with intervals of four hours. Moreover, we analyzed relationship of cell division and fluorescence intensity over the filaments of cells. The results showed that the cell division was not synchronized. We also found a periodicity in the fluorescence intensity of the cells over a single filament, which changed as a function of time after nitrogen depletion. The spatial periodicity may be related to heterocyst pattern.
