When lowering temperature, the in vivo circadian clock in cyanobacteria follows and surpasses the in vitro protein clock trough the Hopf bifurcation

Fuente: arXiv
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Autori principali: Mihalcescu, I., Kaji, H., Maruyama, H., Giraud, J., Gateau, M. Van-Melle, Houchmandzadeh, B., Ito, H.
Natura: Preprint
Pubblicazione: 2024
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author Mihalcescu, I.
Kaji, H.
Maruyama, H.
Giraud, J.
Gateau, M. Van-Melle
Houchmandzadeh, B.
Ito, H.
author_facet Mihalcescu, I.
Kaji, H.
Maruyama, H.
Giraud, J.
Gateau, M. Van-Melle
Houchmandzadeh, B.
Ito, H.
contents The in vivo circadian clock in single cyanobacteria is studied here by time-lapse fluorescence microscopy when the temperature is lowered below 25°C . We first disentangle the circadian clock behavior from the bacterial cold shock response by identifying a sequence of "death steps" based on cellular indicators. By analyzing only "alive" tracks, we show that the dynamic response of individual oscillatory tracks to a step-down temperature signal is described by a simple Stuart-Landau oscillator model. The same dynamical analysis applied to in vitro data (KaiC phosphorylation level following a temperature step-down) allows for extracting and comparing both clock's responses to a temperature step down. It appears, therefore, that both oscillators go through a similar supercritical Hopf bifurcation. Finally, to quantitatively describe the temperature dependence of the resulting in vivo and in vitro Stuart-Landau parameters $μ(T)$ and $ω_c(T)$, we propose two simplified analytical models: temperature-dependent positive feedback or time-delayed negative feedback that is temperature compensated. Our results provide strong constraints for future models and emphasize the importance of studying transitory regimes along temperature effects in circadian systems.
format Preprint
id arxiv_https___arxiv_org_abs_2409_05537
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle When lowering temperature, the in vivo circadian clock in cyanobacteria follows and surpasses the in vitro protein clock trough the Hopf bifurcation
Mihalcescu, I.
Kaji, H.
Maruyama, H.
Giraud, J.
Gateau, M. Van-Melle
Houchmandzadeh, B.
Ito, H.
Molecular Networks
Biological Physics
The in vivo circadian clock in single cyanobacteria is studied here by time-lapse fluorescence microscopy when the temperature is lowered below 25°C . We first disentangle the circadian clock behavior from the bacterial cold shock response by identifying a sequence of "death steps" based on cellular indicators. By analyzing only "alive" tracks, we show that the dynamic response of individual oscillatory tracks to a step-down temperature signal is described by a simple Stuart-Landau oscillator model. The same dynamical analysis applied to in vitro data (KaiC phosphorylation level following a temperature step-down) allows for extracting and comparing both clock's responses to a temperature step down. It appears, therefore, that both oscillators go through a similar supercritical Hopf bifurcation. Finally, to quantitatively describe the temperature dependence of the resulting in vivo and in vitro Stuart-Landau parameters $μ(T)$ and $ω_c(T)$, we propose two simplified analytical models: temperature-dependent positive feedback or time-delayed negative feedback that is temperature compensated. Our results provide strong constraints for future models and emphasize the importance of studying transitory regimes along temperature effects in circadian systems.
title When lowering temperature, the in vivo circadian clock in cyanobacteria follows and surpasses the in vitro protein clock trough the Hopf bifurcation
topic Molecular Networks
Biological Physics
url https://arxiv.org/abs/2409.05537