Nonrandom structures in the locomotor behavior of Halobacterium: a bifurcation route to chaos?
Halobacteria spontaneously reverse their swimming direction about every 10-15 s. They respond to light stimuli by a transient perturbation of this rhythm. During periodic stimulation the system shows features that are known from nonlinear oscillators. Increasing stimulation frequencies cause the following phenomena: (i) the frequency of reversals follows the stimulation frequency, (ii) transition to a state where a long and a short interval occur alternatingly and further transition to four interval lengths, (iii) appearance of irregular interval sequences, which, in a two-dimensional plot of successive intervals, reveal clearly discernible structures and suggest chaotic motion. A similar series of events can be induced in the absence of periodic stimulation, when a control parameter is changed to various constant levels. The data suggest that the system is governed by deterministic dynamical laws.
Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, Federal Republic of Germany.
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Schimz
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Hildebrand
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D006152:Cyclic GMP / Q000502:physiology; D006217:Halobacterium / Q000502:physiology*; D008027:Light; D009068:Movement; D010507:Periodicity
D006152:Cyclic GMP; D015056:1-Methyl-3-isobutylxanthine