Chinese Physics B, Volume. 29, Issue 9, (2020)
Entrainment mechanism of the cyanobacterial circadian clock induced by oxidized quinone
Fig. 1. Phase shifts induced by oxidized quinone pulse sensed by KaiA. A 4 h pulse is added at CT = 3 h [(a), (d)], CT = 9 h [(b), (e)], and CT = 16 h [(c), (f)], respectively. The kinetic trajectories of the total concentration of phosphorylated KaiC (P-KaiC), which is the sum of S-KaiC, T-KaiC and D-KaiC, are shown in (a)–(c). The corresponding orbits are shown and projected onto the T–S plane over a full circadian cycle (d)–(f). The gray bar represents the duration of adding oxidized quinone.
Fig. 2. Phase shift induced by oxidized quinone pulse sensed by CikA. A 4 h pulse is added at CT = 16 h. The kinetic trajectories of P-KaiC before and after the pulse are shown in (a), and the corresponding orbits projected onto the T–S plane over a full circadian cycle are shown in (b). The gray bar represents the duration of adding oxidized quinone.
Fig. 3. The phase response curve (PRC) of the circadian clock. The horizontal axis represents the circadian time when oxidized quinone pulse is added. Negative (positive) phase shifts correspond to phase delay (advance). The blue line with circles indicates the situation where KaiA senses oxidized quinone with
Fig. 4. Effects of varying the amount of oxidized quinone on phase shifts. Oxidized quinone are added at CT = 8 h and CT = 19 h sensed by KaiA [(a), (b)] and CikA [(c), (d)], respectively. The time courses of P-KaiC and PRCs for various amount of oxidized quinone are shown in [(a), (c)] and [(b), (d)], respectively. The gray bar represents the duration of adding oxidized quinone, which is 2 h.
Fig. 5. Effects of varying the pulse duration (PD) of oxidized quinone on phase shifts. Pulses with different durations of oxidized quinone are added at CT = 8 h and CT = 19 h sensed by KaiA [(a), (b)] and CikA [(c), (d)], respectively. The time courses of P-KaiC and PRCs are shown in [(a), (c)] and [(b), (d)], respectively. Here
Fig. 6. PRCs of circadian oscillators with different inherent periods (
Fig. 7. Entrainment of cyanobacterial circadian clock regulated by oxidized quinone cycle. The blue solid lines and the red dotted lines represent the oscillators without and with oxidized quinone cycle, respectively. The jagged line shows oxidized quinone cycle (12:12), where the high level represents oxidized quinone pulse (12 h) and the low level represents that there is no oxidized quinone (12 h). Oxidized quinone is sensed by KaiA (a) and CikA (b), respectively.
Fig. 8. Mixture effects of KaiA and CikA on the entrainment of circadian clock. The circadian clock can not be entrained when the signal strength of oxidized quinone, sensed by one of KaiA or CikA, is not strong enough (a). However, it can be entrained when oxidized quinone is sensed by both KaiA and CikA (b). The time evolution curves of P-KaiC with varying
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Ying Li, Guang-Kun Zhang, Zi-Gen Song. Entrainment mechanism of the cyanobacterial circadian clock induced by oxidized quinone[J]. Chinese Physics B, 2020, 29(9):
Received: Jun. 4, 2020
Accepted: --
Published Online: Apr. 29, 2021
The Author Email: Li Ying (leeliying@163.com)