Université de Genève

Circadian liver gene expression : hepatocyte clock dependent and independent oscillations

Kornmann, Benoît ; Schibler, Ueli (Dir.)

Thèse de doctorat : Université de Genève, 2006 ; Sc. 3727.

Des oscillateurs circadiens capables de générer des rythmes d'environ 24 heures sont présents au coeur de chaque cellule et contrôlent de nombreux aspects de la physiologie en régulant une partie du transcriptome. Ces oscillateurs restent synchronisés grâce au travail d'un oscillateur "chef d'orchestre" dans l'hypothalamus. Nous avons généré des souris trangéniques dans lesquelles les...

Université de Fribourg

Life time—circadian clocks, mitochondria and metabolism

Langmesser, Sonja ; Albrecht, Urs

In: Chronobiology International, 2006, vol. 23, no. 1-2, p. 51–157

A functional circadian clock has long been considered a selective advantage. Accumulating evidence shows that the clock coordinates a variety of physiological processes in order to schedule them to the optimal time of day and thus to synchronize metabolism to changes in external conditions. In mitochondria, both metabolic and cellular defense mechanisms are carefully regulated. Abnormal clock...

Université de Fribourg

A guideline for analyzing circadian wheel-running behavior in rodents under different lighting conditions

Jud, Corinne ; Schmutz, Isabelle ; Hampp, Gabriele ; Oster, Henrik ; Albrecht, Urs

In: Biological Procedures Online 2005, 7(1)/101-116/

Most behavioral experiments within circadian research are based on the analysis of locomotor activity. This paper introduces scientists to chronobiology by explaining the basic terminology used within the field. Furthermore, it aims to assist in designing, carrying out, and evaluating wheel-running experiments with rodents, particularly mice. Since light is an easily applicable stimulus that...

Université de Fribourg

Phase Responses to Light Pulses in Mice Lacking Functional per or cry Genes

Spoelstra, Kamiel ; Albrecht, Urs ; Horst, Gijsbertus T. J. van der ; Brauer, Verena ; Daan, Serge

In: Journal of Biological Rhythms, 2004, vol. 19 (6), p. 518-529

The phase-resetting properties of the circadian system in mice with a functional deletion in mCry1, mCry2, mPer1, or mPer2 were studied in 2 experiments. In experiment 1, mCry1-/- and mCry2-/- mice as well as mPer1Brdm1 and mPer2Brdm1 mutant mice were exposed to 15-min light pulses during the 1st cycle following entrainment, either early (external time [ExT] 20) or late (ExT 4) in the subjective...

Université de Fribourg

Circadian expression of the clock gene Per2 is altered in the ruin lizard (Podarcis sicula) when temperature changes

Magnone, Maria Chiara ; Jacobmeier, Birgit ; Bertolucci, Cristiano ; Foà, Augusto ; Albrecht, Urs

In: Molecular Brain Research, 2005, vol. 133, p. 281-286

When exposed to the cold, the body temperature of the ruin lizard (Podarcis sicula), an ectothermic vertebrate, comes into equilibrium with that low environmental temperature. During this time, the behavioral output of the circadian clock, locomotor activity, disappears. We tested the activity of the circadian clockwork at low temperature (6 °C) by following the expression of one of its...