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Université de Fribourg

Membrane rafts are involved in intracellular miconazole accumulation in yeast cells

François, Isabelle E. J. A. ; Bink, Anna ; Vandercappellen, Jo ; Ayscough, Kathryn R. ; Toulmay, Alexandre ; Schneiter, Roger ; Gyseghem, Elke van ; Mooter, Guy Van den ; Borgers, Marcel ; Vandenbosch, Davy ; Coenye, Tom ; Cammue, Bruno P. A. ; Thevissen, Karin

In: The Journal of Biological Chemistry, 2009, vol. 284, p. 32680-32685

Azoles inhibit ergosterol biosynthesis, resulting in ergosterol depletion and accumulation of toxic 14α-methylated sterols in membranes of susceptible yeast. We demonstrated previously that miconazole induces actin cytoskeleton stabilization in Saccharomyces cerevisiae prior to induction of reactive oxygen species, pointing to an ancillary mode of action. Using a genome-wide agar-based...

Université de Fribourg

The Cdc42 effectors ste20, Cla4, and Skm1 down-regulate the expression of genes involved in sterol uptake by a mitogen-activated protein kinase-independent pathway

Lin, Meng ; Unden, Heike ; Jacquier, Nicolas ; Schneiter, Roger ; Just, Ursula ; Höfken, Thomas

In: Molecular Biology of the Cell, 2009, vol. 20, no. 22, p. 4826-4837

In Saccharomyces cerevisiae, the Rho-type GTPase Cdc42 regulates polarized growth through its effectors, including the p21-activated kinases (PAKs) Ste20, Cla4, and Skm1. Previously, we demonstrated that Ste20 interacts with several proteins involved in sterol synthesis that are crucial for cell polarization. Under anaerobic conditions, sterols cannot be synthesized and need to be imported into...

Université de Fribourg

The brain under self-control: modulation of inhibitory and monitoring cortical networks during hypnotic paralysis

Cojan, Yann ; Waber, Lakshmi ; Schwartz, Sophie ; Rossier, Laurent ; Forster, Alain ; Vuilleumier, Patrik

In: Neuron, 2009, vol. 62, no. 6, p. 862-875

Brain mechanisms of hypnosis are poorly known. Cognitive accounts proposed that executive attentional systems may cause selective inhibition or disconnection of some mental operations. To assess motor and inhibitory brain circuits during hypnotic paralysis, we designed a go-nogo task while volunteers underwent functional magnetic resonance imaging (fMRI) in three conditions: normal state,...

Université de Fribourg

The brain-specific Neural Zinc Finger transcription factor 2b (NZF-2b/7ZFMyt1) causes suppression of cocaine-induced locomotor activity

Chandrasekar, Vijay ; Dreyer, Jean-Luc

In: Neurobiology of Disease, 2009, vol. 37, no. 1, p. 86-98

Chronic cocaine induces high expression of the brain-specific Neural-Zinc-Finger transcription factor-2b (NZF-2b/7ZFMyt1), particularly in the mesolimbic dopaminergic pathway, resulting in a 11-fold increase in NZF-2b/7ZFMyt1 expression in the Nucleus Accumbens (NAc). Overexpression of this gene in the NAc with a NZF-2b/7ZFMyt1-expressing lentivirus resulted in >55% decrease in locomotor activity...

Université de Fribourg

cGMP-dependent protein kinase type I is implicated in the regulation of the timing and quality of sleep and wakefulness

Langmesser, Sonja ; Franken, Paul ; Feil, Susanne ; Emmenegger, Yann ; Albrecht, Urs ; Feil, Robert

In: PLoS ONE, 2009, vol. 4, no. 1, p. e4238

Many effects of nitric oxide (NO) are mediated by the activation of guanylyl cyclases and subsequent production of the second messenger cyclic guanosine-3′,5′-monophosphate (cGMP). cGMP activates cGMP-dependent protein kinases (PRKGs), which can therefore be considered downstream effectors of NO signaling. Since NO is thought to be involved in the regulation of both sleep and circadian...

Université de Fribourg

Experimental evolution of field populations of Daphnia magna in response to parasite treatment

Zbinden, Marc ; Haag, Christoph R. ; Ebert, Dieter

In: Journal of Evolutionary Biology, 2008///doi:10.1111/j.1420-9101.2008.01541.x

Although there is little doubt that hosts evolve to reduce parasite damage, little is known about the evolutionary time scale on which host populations may adapt under natural conditions. Here we study the effects of selection by the microsporidian parasite Octosporea bayeri on populations of Daphnia magna. In a field study, we infected replicated populations of D. magna with the parasite,...

Université de Fribourg

Characterization and biological function of the ISOCHORISMATE SYNTHASE 2 gene of Arabidopsis thaliana

Garcion, Christophe ; Lohmann, Antje ; Lamodiere, Elisabeth ; Catinot, Jeremy ; Buchala, Antony J. ; Doermann, Peter ; Métraux, Jean-Pierre

In: Plant Physiology, 2009, p. -

Salicylic acid (SA) is an important mediator of plant defense response. In Arabidopsis thaliana, this compound was proposed to derive mainly from isochorismate, itself produced from chorismate through the activity of ICS1 (Isochorismate Synthase1). Null ics1 mutants still accumulate some SA, suggesting the existence of an enzymatic activity redundant with ICS1 or of an alternative...

Université de Fribourg

6S1/2-6P1/2 transition of Cs atoms in cubic and hexagonal solid ⁴He

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

In: Physical Review A, 2007, vol. 76, no. 2, p. 022502

We present a systematic experimental study of the absorption and fluorescence spectra of the 6S1/2-6P1/2 transition in Cs atoms isolated in solid ⁴He matrices. The bubble model developed earlier for alkali-metal atoms in liquid He is revised and applied to the present system. The analysis of the dependencies of absorption and fluorescence wavelengths on He...

Université de Fribourg

Pentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes

Pusnik, Mascha ; Small, Ian ; Read, Laurie K. ; Fabbro, Thomas ; Schneider, André

In: Molecular and Cellular Biology, 2007, vol. 27, no. 19, p. 6876-6888

The pentatricopeptide repeat (PPR), a degenerate 35-amino-acid motif, defines a novel eukaryotic protein family. Plants have 400 to 500 distinct PPR proteins, whereas other eukaryotes generally have fewer than 5. The few PPR proteins that have been studied have roles in organellar gene expression, probably via direct interaction with RNA. Here we show that the parasitic protozoan Trypanosoma...

Université de Fribourg

Bax function in the absence of mitochondria in the primitive protozoan Giardia lamblia

Hehl, Adrian B. ; Regos, Attila ; Schraner, Elisabeth ; Schneider, André

In: PLoS ONE, 2007, vol. 2, no. 5, p. e488

Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia...