Biochemical studies on Anacystis nidulans during its synchronous growth

Macromolecular synthesis in synchronized cultures of Anacystis nidulans

Synchronous culture of Anacystis nidulans has been induced by the light-dark-light regimen. At various time intervals during synchronous growth, samples were pulsed with radioactive labels to determine phospholipid, protein, ribonucleic acid (RNA), and deoxyribonucleic acid (DNA) syntheses within the cell division cycle. A temporal order of protein, RNA, and DNA syntheses occurred within the cell division cycle, whereas phospholipid was characteristically synthesized during midcycle (during cell enlargement) and during the time of cell division. Chemically determined protein, RNA, and DNA syntheses were found to support the schedule of these macromolecules in cultures growing at an 8-h doubling time.

Synchronization of Anacystis nidulans. Oxygen evolution during the cell cycle

A new technique of short alternating light-dark periods was successfully used to synchronize the blue-green alga Anacystis nidulans. Oxygen evolution during the cell cycle is characterized by a maximum in the middle of the cycle and by a minimum at the time of division, a pattern very similar to that found in synchronized green algae.

Purification of Synechococcus lividus by equilibrium centrifugation and its synchronization by differential centrifugation

A culture of the thermophilic, unicellular, blue-green alga Synechococcus lividus was freed from two thermophilic bacteria by use of equilibrium (isopycnic) centrifugation in Ficoll density gradients. After removal of the bacteria, the alga would grow only on agar plates in a high carbon dioxide atmosphere. Intermittent illumination, equilibrium centrifugation, and differential centrifugation were tested as techniques for obtaining synchronized cultures of the alga. Daughter cells selected by differential centrifugation in Ficoll density gradients yielded the best synchrony, and a cross-wall index of 85% was observed during the period of cell division.

Physiology and cytological chemistry blue-green algae

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