Monitoring Heterocyst Isolation in Anabaena PCC 7119

The purification of isolated and intact heterocysts is an essential step in the study and characterisation of their specific proteins. Therefore, a method for very successful heterocyst isolation from filamentous cyanobacteria, as monitored by measuring the presence of ferredoxin-NADP⁺ reductase activity during the isolation procedure has been developed. This is an improvement over the current lysozyme method in which damage could be caused to the heterocysts septum releasing soluble proteins. Frozen filaments should not be used for heterocysts isolation.