Free, conjugated and bound polyamines during the cell cycle in synchronized cultures of Scenedesmus obliquus.

The levels of free, conjugated and bound polyamines (PA) were analyzed during the cell cycle of the synchronized unicellular green alga Scenedesmus obliquus. The polyamines putrescine (PUT) and spermidine (SPD) in their free and conjugated forms accumulated per cell to a maximum in the cell cycle at about the 16th hour after onset of illumination. The polyamines bound to macromolecules and membrane systems showed an additional peak around the 8-10th hour of the cell cycle. The possible role of the different forms of polyamines in DNA replication, mitosis, cell division and development of the photosynthetic apparatus is discussed.