PH oscillations in cell suspensions of Dictyostelium discoideum: their relation to cyclic-amp signals

1978 ◽  
Vol 30 (1) ◽  
pp. 319-330
Author(s):  
D. Malchow ◽  
V. Nanjundiah ◽  
G. Gerisch
Keyword(s):  
Phase Shift ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Response Curve ◽  
Phase Response Curve ◽  
Cell Suspensions ◽  
Phase Response ◽  
Temporary Increase ◽  
Rhythmic Stimulation

Cells of Dictyostelium discoideum known to release cyclic AMP (cAMP) rhythmically in the form of pulses, change with the same period of about 8 min the pH of their medium. The pH is used here as an indicator to investigate the effect of externally added cAMP pulses on the oscillations. Both a temporary increase in amplitude and a permanent phase shift can be induced. The phase-response curve indicates that the period can be increased and decreased by rhythmic stimulation with cAMP pulses.

scholarly journals An increase in cytosolic Ca2+ delays cAMP oscillations in Dictyostelium cells

1996 ◽  
Vol 319 (1) ◽  
pp. 323-327 ◽  
Author(s):  
Dieter MALCHOW ◽  
Ralph SCHALOSKE ◽  
Christina SCHLATTERER
Keyword(s):  
Light Scattering ◽  
Dictyostelium Discoideum ◽  
Response Curve ◽  
Phase Response Curve ◽  
Phase Delay ◽  
Phase Response ◽  
Transient Increase ◽  
Camp Synthesis ◽  
Similar Phase ◽  
Oscillatory Cycle

We have shown that calmidazolium (R24571) causes a transient increase in the cytosolic free Ca2+ concentration ([Ca2+]i) in Dictyostelium discoideum [Schlatterer and Schaloske (1996) Biochem. J. 313, 661–667]. Here we have used R24571 to artificially increase [Ca2+]i during light-scattering oscillations and have found that, depending on the time of addition during the oscillatory cycle, R24571 suppressed cAMP synthesis and delayed the next spike for several minutes. Addition of Ca2+ to the medium, which also elevates [Ca2+]i, induced phase delays and resulted in a similar phase response curve as R24571. The magnitude of the phase delay was correlated with the point during the oscillatory cycle at which Ca2+ was added, indicating that an artificial increase in [Ca2+]i also resets the phase of the intrinsic oscillator.

Spike-shaped oscillations in the absence of measurable changes in cyclic AMP concentration in a mutant of Dictyostelium discoideum

1987 ◽  
Vol 87 (5) ◽  
pp. 723-730
Author(s):  
B. Wurster ◽  
R. Mohn
Keyword(s):  
Light Scattering ◽  
Cyclic Amp ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Cyclic Gmp ◽  
Parent Strain ◽  
Reaction System ◽  
Cell Suspensions ◽  
Deficient Mutant ◽  
Cyclic Amp Synthesis

Periodic activities of Dictyostelium discoideum cells involve two types of oscillations, spike-shaped and sinusoidal. Spike-shaped oscillations are accompanied by the periodic synthesis and release of cyclic AMP, and cyclic AMP-activated cyclic AMP synthesis is believed to control these oscillations. Experiments described here call into question the importance of cyclic AMP in spike-shaped oscillations. Cell suspensions of strain agip43, an aggregation-deficient mutant of D. discoideum, displayed spike-shaped oscillations in light scattering with period lengths about 1.5 times larger than those of the parent strain. These oscillations were not accompanied by measurable oscillations of cyclic AMP and cyclic GMP. Applied cyclic AMP pulses elicited increases of two- to threefold in the cyclic AMP level and increases of seven- to ninefold in the cyclic GMP concentration. Cyclic AMP additions caused phase shifts in the oscillations of agip43 cells, suggesting that cyclic AMP receptors at the cell surface communicate with the oscillator. We interpret these results in terms of an oscillator not based on cyclic AMP. This oscillator should be coupled to the reaction system involving cyclic AMP synthesis and release. The latter can operate in an oscillatory manner in the parent strain Ax2 but not in mutant agip43.

Synchronization of two coupled pacemaker cells based on the phase response curve

2009 ◽  
Vol 4 (1) ◽  
pp. 57-66
Author(s):  
Hossein Gholizade-Narm ◽  
Asad Azemi ◽  
Morteza Khademi ◽  
Masoud Karimi-Ghartemani
Keyword(s):  
Response Curve ◽  
Phase Response Curve ◽  
Phase Response ◽  
Pacemaker Cells

Phosphofructokinase controls the acetaldehyde-induced phase shift in isolated yeast glycolytic oscillators

2019 ◽  
Vol 476 (2) ◽  
pp. 353-363
Author(s):  
David D. van Niekerk ◽  
Anna-Karin Gustavsson ◽  
Martin Mojica-Benavides ◽  
Caroline B. Adiels ◽  
Mattias Goksör ◽  
...  
Keyword(s):  
Phase Shift ◽  
Phase Response Curve ◽  
Mechanistic Model ◽  
Phase Response ◽  
Yeast Cells ◽  
Emergent Properties ◽  
Functional Coupling ◽  
External Signal ◽  
Oscillatory Systems ◽  
External Perturbations

Abstract The response of oscillatory systems to external perturbations is crucial for emergent properties such as synchronisation and phase locking and can be quantified in a phase response curve (PRC). In individual, oscillating yeast cells, we characterised experimentally the phase response of glycolytic oscillations for external acetaldehyde pulses and followed the transduction of the perturbation through the system. Subsequently, we analysed the control of the relevant system components in a detailed mechanistic model. The observed responses are interpreted in terms of the functional coupling and regulation in the reaction network. We find that our model quantitatively predicts the phase-dependent phase shift observed in the experimental data. The phase shift is in agreement with an adaptation leading to synchronisation with an external signal. Our model analysis establishes that phosphofructokinase plays a key role in the phase shift dynamics as shown in the PRC and adaptation time to external perturbations. Specific mechanism-based interventions, made possible through such analyses of detailed models, can improve upon standard trial and error methods, e.g. melatonin supplementation to overcome jet-lag, which are error-prone, specifically, since the effects are phase dependent and dose dependent. The models by Gustavsson and Goldbeter discussed in the text can be obtained from the JWS Online simulation database: (https://jjj.bio.vu.nl/models/gustavsson5 and https://jjj.bio.vu.nl/models/goldbeter1)

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