Abstract
Times of the induction and of commitment to sporulation and variations in intracellular nucleotide (ATP, ADP, AMP, CTP, CDP, UTP, UDP) and cyclic nucleotide (cAMP, cGMP) concentrations were determined from the time at which starved plasmodia were exposed to continuous light until sporulation about 10 h after illumination. Induction took place after about 1 h, a burst of cAMP and cGMP concentrations occurring at about the same time. Plasmodia acquired the commitment after about 4.5 h, which corresponded to the second-rising phase of the oscillating nucleotide concen-trations. All the nucleotides studied oscillated virtually in phase, evidence that oscillation is related to conversion between monomeric and polymeric nucleotides. Anaerobic conditions suppressed both sporulation and oscillation of the intracellular nucleotide concentrations. The rate of O2 uptake decreased on illumination, but did not oscillate. Sporulation is discussed in terms of nonlinear dynamics as a bifurcation from stable to oscillatory branches in an open nonequilibrium system.
