Lysozyme attacks the walls of the vegetative cells and produces protoplasts. The wall of the heterocyst is not affected, but the polar region is elongated linearly to form thick and long stalks. Unequal elongation of the stalks results in the pushing out of the protoplast from the shell of the heterocyst. Sometimes the stalks are of unusual length, coiled irregularly or twisted, but still attached to the protoplast of the heterocyst.