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Université de Fribourg

Integration of complex larval chemosensory organs into the adult nervous system of Drosophila

Gendre, Nanaë ; Lüer, Karin ; Friche, Sandrine ; Grillenzoni, Nicola ; Ramaekers, Ariane ; Technau, Gerhard M. ; Stocker, Reinhard F.

In: Development, 2004, vol. 131, p. 83-92

The sense organs of adult Drosophila, and holometabolous insects in general, derive essentially from imaginal discs and hence are adult specific. Experimental evidence presented here, however, suggests a different developmental design for the three largely gustatory sense organs located along the pharynx. In a comprehensive cellular analysis, we show that the posteriormost of the three organs...

Université de Fribourg

The T-stem determines the cytosolic or mitochondrial localization of trypanosomal tRNAsMet

Crausaz Esseiva, Anne ; Maréchal-Drouard, Laurence ; Cosset, Anne ; Schneider, André

In: Molecular Biology of the Cell, 2004, vol. 15, p. 2750-2757

The mitochondrion of Trypanosoma brucei lacks tRNA genes. Organellar translation therefore depends on import of cytosolic, nucleus-encoded tRNAs. Except for the cytosol-specific initiator tRNAMet, all trypanosomal tRNAs function in both the cytosol and the mitochondrion. The initiator tRNAMet is closely related to the imported elongator tRNAMet. Thus, the distinct localization of the two tRNAsMet...

Université de Fribourg

Expression of a major surface protein of Trypanosoma brucei insect forms is controlled by the activity of mitochondrial enzymes

Vassella, Erik ; Probst, Matthias ; Schneider, André ; Studer, Erwin ; Kunz Renggli, Christina ; Roditi, Isabel

In: Molecular Biology of the Cell, 2004, vol. 15, p. 3986-3993

In cycling between the mammalian host and the tsetse fly vector, trypanosomes undergo major changes in energy metabolism and surface coat composition. Early procyclic (insect) forms in the tsetse fly midgut are coated by glycoproteins known as EP and GPEET procyclins. EP expression continues in late procyclic forms, whereas GPEET is down-regulated. In culture, expression of GPEET is modulated by...

Université de Fribourg

Dissecting the ß-aminobutyric acid–induced priming phenomenon in Arabidopsis

Ton, Jurriaan ; Jakab, Gabor ; Toquin, Valérie ; Flors, Victor ; Iavicoli, Annalisa ; Maeder, Muriel N. ; Métraux, Jean-Pierre ; Mauch-Mani, Brigitte

In: The Plant Cell, 2005, vol. 17, p. 987-999

Plants treated with the nonprotein amino acid ß-aminobutyric acid (BABA) develop an enhanced capacity to resist biotic and abiotic stresses. This BABA-induced resistance (BABA-IR) is associated with an augmented capacity to express basal defense responses, a phenomenon known as priming. Based on the observation that high amounts of BABA induce sterility in Arabidopsis thaliana, a mutagenesis...

Université de Fribourg

Developmental origin of wiring specificity in the olfactory system of Drosophila

Jefferis, Gregory S. X. E. ; Vyas, Raj M. ; Berdnik, Daniela ; Ramaekers, Ariane ; Stocker, Reinhard F. ; Tanaka, Nobuaki K. ; Ito, Kei ; Luo, Liqun

In: Development, 2004, vol. 131, p. 117-130

In both insects and mammals, olfactory receptor neurons (ORNs) expressing specific olfactory receptors converge their axons onto specific glomeruli, creating a spatial map in the brain. We have previously shown that second order projection neurons (PNs) in Drosophila are prespecified by lineage and birth order to send their dendrites to one of ~50 glomeruli in the antennal lobe. How can a given...

Université de Fribourg

Paradoxes in the logistic equation?

Gabriel, Jean-Pierre ; Saucy, Francis ; Bersier, Louis-Félix

In: Ecological Modelling

Levins and Ginzburg raised two paradoxes concerning the logistic equation of population growth. None of them received a satisfactory answer within the frame of the original equation. Here, we propose solutions to both paradoxes.

Université de Fribourg

Sulphur deficiency causes a reduction in antimicrobial potential and leads to increased disease susceptibility of oilseed rape

Dubuis, Pierre-Henri ; Marazzi, Cristina ; Städler, Erich ; Mauch, Felix

In: Journal of Phytopathology, 2005, vol. 153, p. 27-36

The reduction of atmospheric sulphur dioxide pollution is causing increasing problems of sulphur deficiency in sulphur-demanding crop plants in northern Europe. Elemental sulphur and many sulphur containing compounds such as cysteine-rich antifungal proteins, glucosinolates (GSL) and phytoalexins play important roles in plant disease resistance. The aim of this work was to analyse the effect of...

Université de Fribourg

Gene-specific Involvement of ß-oxidation in wound-activated responses in Arabidopsis

Castillo, M. Cruz ; Martínez, Cristina ; Buchala, Antony ; Métraux, Jean-Pierre ; León, José

In: Plant Physiology, 2004, vol. 135, p. 95-104

The coordinated induced expression of ß-oxidation genes is essential to provide the energy supply for germination and postgerminative development. However, very little is known about other functions of ß-oxidation in nonreserve organs. We have identified a gene-specific pattern of induced ß-oxidation gene expression in wounded leaves of Arabidopsis. Mechanical damage triggered the local and...

Université de Fribourg

Crosstalk and differential response to abiotic and biotic stressors reflected at the transcriptional level of effector genes from secondary metabolism

Glombitza, Sabine ; Dubuis, Pierre-henri ; Thulke, Oliver ; Welzl, Gerhard ; Bovet, Lucien ; Götz, Michael ; Affenzeller, Matthias ; Geist, Birgit ; Hehn, Alain ; Asnaghi, Carole ; Ernst, Dieter ; Seidlitz, Harald ; Gundlach, Heidrun ; Mayer, Klaus ; Martinoia, Enrico ; Werck-reichhart, Daniele ; Mauch, Felix ; Schäffner, Anton

In: Plant Molecular Biology, 2005, vol. 54, p. 817-835

Plant secondary metabolism significantly contributes to defensive measures against adverse abiotic and biotic cues. To investigate stress-induced, transcriptional alterations of underlying effector gene families, which encode enzymes acting consecutively in secondary metabolism and defense reactions, a DNA array (MetArray) harboring gene-specific probes was established. It comprised complete sets...

Université de Fribourg

Toward a digital database of plant cell signalling networks: advantages, limitations and predictive aspects of the digital model

Treviño Santa Cruz, Marcela Beatriz ; Genoud, Dominique ; Métraux, Jean-Pierre ; Genoud, Thierry

In: Phytochemistry, 2005, vol. 66, p. 267-277

The process of signal integration, which contributes to the regulation of multiple cellular activities, can be described in a digital language by a set of connected digital operations. In this article we delineate the basic concepts of cell signalling in the context of a logical description of information processing. Newly described instances of signal integration in plants are given as examples....