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Université de Fribourg

Identification and biophysical characterization of a very-long-chain-fatty-acid-substituted phosphatidylinositol in yeast subcellular membranes

Schneiter, Roger ; Brügger, Britta ; Amann, Clare M. ; Prestwich, Glenn D. ; Epand, Raquel F. ; Zellnig, Günther ; Wieland, Felix T. ; Epand, Richard M.

In: Biochemical Journal, 2004, vol. 381, p. 941-949

Morphological analysis of a conditional yeast mutant in acetyl-CoA carboxylase acc1ts/mtr7, the rate-limiting enzyme of fatty acid synthesis, suggested that the synthesis of C₂₆ VLCFAs (very-long-chain fatty acids) is important for maintaining the structure and function of the nuclear membrane. To characterize this C₂₆-dependent pathway in more detail, we have now examined cells that are...

Université de Fribourg

Acyl-CoA-binding protein, Acb1p, is required for normal vacuole function and ceramide synthesis in Saccharomyces cerevisiae

Faergeman, Nils J. ; Feddersen, Søren ; Christiansen, Janne K. ; Larsen, Morten K. ; Schneiter, Roger ; Ungermann, Christian ; Mutenda, Kudzai ; Roepstroff, Peter ; Knudsen, Jens

In: Biochemical Journal, 2004, vol. 380, p. 907-918

In the present study, we show that depletion of acyl-CoA-binding protein, Acb1p, in yeast affects ceramide levels, protein trafficking, vacuole fusion and structure. Vacuoles in Acb1p-depleted cells are multi-lobed, contain significantly less of the SNAREs (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors) Nyv1p, Vam3p and Vti1p, and are unable to fuse in vitro. Mass...

Université de Fribourg

Adaptive thermogenesis and uncoupling proteins: a reappraisal of their roles in fat metabolism and energy balance

Dulloo, Abdul G. ; Seydoux, Josiane ; Jacquet, Jean

In: Physiology & Behavior, 2004, vol. 83, no. 4, p. 587-602

After decades of controversies about the quantitative importance of autoregulatory adjustments in energy expenditure in weight regulation, there is now increasing recognition that even subtle variations in thermogenesis could, in dynamic systems and over the long term, be important in determining weight maintenance in some and obesity in others. The main challenge nowadays is to provide a...

Université de Fribourg

Cocaine-induced expression changes of axon guidance molecules in the adult rat brain

Bahi, Amine ; Dreyer, Jean-Luc

In: Molecular and Cellular Neuroscience, 2005, vol. 28(2), p. 275-291

Administration of drugs of abuse induces strong molecular adaptations and plasticity within the mesolimbic dopamine (DA) system, a pathway essential for reward-seeking behavior. Little is known about the specific targets involved in this neuroadaptation process, but there are indications that cocaine and other drugs of abuse share the ability to alter the morphology of neuronal dendrites and...

Université de Fribourg

Parvalbumin deficiency affects network properties resulting in increased susceptibility to epileptic seizures

Schwaller, Beat ; Tetko, I. V. ; Tandon, P. ; Silveira, D. C. ; Vreugdenhil, M. ; Henzi, Thomas ; Potier, M. -C. ; Celio, Marco R. ; Villa, A. E. P.

In: Molecular and Cellular Neuroscience, 2004, vol. 25, no. 4, p. 650-663

Networks of GABAergic interneurons are of utmost importance in generating and promoting synchronous activity and are involved in producing coherent oscillations. These neurons are characterized by their fast-spiking rate and by the expression of the Ca2+-binding protein parvalbumin (PV). Alteration of their inhibitory activity has been proposed as a major mechanism leading to epileptic seizures...

Université de Fribourg

Circadian Genes in a Blind Subterranean Mammal III: Molecular Cloning and Circadian Regulation of Cryptochrome Genes in the Blind Subterranean Mole Rat, Spalax Ehrenbergi Superspecies

Avivi, Aaron ; Oster, Henrik ; Joel, Alma ; Beiles, Avigdor ; Albrecht, Urs ; Nevo, Eviatar

In: Journal of Biological Rhythms, 2004, vol. 19, no. 1, p. 22-34

The blind subterranean mole rat superspecies Spalax ehrenbergi is an extreme example of mammalian adaptation to life underground. Though this rodent is totally visually blind, harboring a drastically degenerated subcutaneous rudimentary eye, its daily activity rhythm is entrainable to LD cycles. This indicates that it confers light information to the clock, as has been previously shown by the...

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...

Université de Fribourg

The clock gene Per2 influences the glutamatergic system and modulates alcohol consumption

Spanagel, Rainer ; Pendyala, Gurudutt ; Abarca, Carolina ; Zghoul, Tarek ; Sanchis-Segura, Carles ; Magnone, Maria Chiara ; Lascorz, Jesús ; Depner, Martin ; Holzberg, David ; Soyka, Michael ; Schreiber, Stefan ; Matsuda, Fumihiko ; Lathrop, Mark ; Schumann, Gunter ; Albrecht, Urs

In: Nature Medicine, 2004, vol. 11, p. 35-42

Period (Per) genes are involved in regulation of the circadian clock and are thought to modulate several brain functions. We demonstrate that Per2Brdm1 mutant mice, which have a deletion in the PAS domain of the Per2 protein, show alterations in the glutamatergic system. Lowered expression of the glutamate transporter Eaat1 is observed in these animals, leading to reduced uptake of glutamate by...

Université de Fribourg

Discovery of dumbbell-shaped CsHe(n) exciplexes in solid ⁴He

Nettels, Daniel ; Hofer, Adrian ; Moroshkin, Peter ; Müller-Siebert, Reinhard ; Ulzega, Simone ; Weis, Antoine

In: Physical Review Letters, 2005, vol. 94, p. 063001

We have observed several new spectral features in the fluorescence of cesium atoms implanted in the hcp phase of solid helium following laser excitation to the 6²P states. Based on calculations of the emission spectra using semi empirical Cs-He pair potentials the newly discovered lines can be assigned to the decay of specific Cs*He(n) exciplexes: an apple-shaped Cs(AП(3/2))He₂ and a...