DEPARTMENT of BIOLOGY at the UNIVERSITY of FRIBOURG
The Department of Biology is now composed of four functional groups - Biochemistry, Ecology and Evolution, Plant Biology and Zoology, each with several distinct research groups which you are invited to visit at the above links. Teaching at both the Bachelor and Master levels reflects the interests of the research groups and the respective programmes can be consulted using the appropriate links in the left column (in French and German for the Bachelor and in English for the Master).
Coming events & news
- 28th & 29th May: Presentation of BSc projects
The annual presentation of the results obtained by BSc students during their personal project will be held on the 28th (pm) & 29th (am & pm) May in seminar room 0.109 at Plant Biology - 29th May: Annual General Meeting/Assemblée plénière/Jahreshauptversammlung of the Dept of Biology
All biology students, technical and administrative staff, research workers and teaching staff are cordially invited to attend the annual general meeting of the Department to be held at 17.15h in lecture theatre 0.110 at Plant Biology. This will be followed by the traditional BBQ in the Botanical Garden - inscription before the 22nd May. - The next Biology seminar will be held on the 14th May
Rodolfo Costa (Dept. Biology, University of Padova) Will give a talk entitled "The fly Cryptochrome and the visual system"
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Publication "hot spot"
Ypc1p and Ydc1p are alkaline ceramide hydrolases, which reside in the ER. Ypc1p can catalyze the reverse reaction, i.e. the condensation of free fatty acids with phytosphingosine or dihydrosphingosine and overexpression of YPC1 or YDC1 can provide enough ceramide synthesis as to rescue the viability of cells lacking the normal acyl-CoA-dependent ceramide synthases. To better understand the coexistence of acyl-CoA dependent ceramide synthases and ceramidases in the ER we investigated the membrane topology of Ypc1p by probing cysteine accessibility of natural and substituted cysteines with membrane non-permeating mass-tagged probes. The N- and C-terminal ends of Ypc1p are oriented towards the lumen and cytosol, respectively. Two of the 5 natural cysteines, Cys27 and Cys219, are essential for enzymatic activity and form a disulfide bridge. The data allow inferring that all amino acids of Ypc1p that are conserved in the pfam PF05875 ceramidase motif and the CREST superfamily are located in or near the ER lumen. Microsomal assays using a lysine-specific reagent show that the reverse ceramidase activity can only be blocked when the reagent has access to Ypc1p from the lumenal side. Overall the data suggest that the active site of Ypc1p resides at the lumenal side of the ER membrane. |
Egger B, Van Giesen L, Moraru M & Sprecher SG (2013). In vitro imaging of primary neural cell culture from Drosophila. Nature Protocols 8: 958-965. Cell culture systems are widely used for molecular, genetic and biochemical studies. Primary cell cultures of animal tissues offer the advantage that specific cell types can be studied in vitro outside of their normal environment. We provide a detailed protocol for generating primary neural cell cultures derived from larval brains of Drosophila melanogaster. The developing larval brain contains stem cells such as neural precursors and intermediate neural progenitors, as well as fully differentiated and functional neurons and glia cells. We describe how to analyze these cell types in vitro by immunofluorescent staining and scanning confocal microscopy. Cell type-specific fluorescent reporter lines and genetically encoded calcium sensors allow the monitoring of developmental, cellular processes and neuronal activity in living cells in vitro. The protocol provides a basis for functional studies of wild-type or genetically manipulated primary neural cells in culture, both in fixed and living samples. The entire procedure takes ∼3 weeks. . |
S Bontron, M Jaquenoud, S Vaga, N Talarek, B Bodenmiller, R Aebersold &C De Virgilio (2013). Yeast endosulfines control entry into quiescence and chronological life span by inhibiting protein phosphatase 2A. Cell Reports 3: 16-22 (doi:10.1016/j.celrep.2012.11.025) The TORC1 and PKA protein kinases are central elements of signaling networks that regulate eukaryotic cell proliferation in response to growth factors and/or nutrients. In yeast, attenuation of signaling by these kinases following nitrogen and/or carbon limitation activates the protein kinase Rim15, which orchestrates the initiation of a reversible cellular quiescence program to ensure normal chronological life span. The molecular elements linking Rim15 to distal readouts including the expression of Msn2/4- and Gis1-dependent genes involve the endosulfines Igo1/2. We show that Rim15, analogous to the greatwall kinase in Xenopus, phosphorylates endosulfines to directly inhibit the Cdc55-protein phosphatase 2A (PP2ACdc55). Inhibition of PP2ACdc55 preserves Gis1 in a phosphorylated state and consequently promotes its recruitment to and activation of transcription from promoters of specific nutrient-regulated genes. These results close a gap in our perception of and delineate a role for PP2ACdc55 in TORC1-/PKA-mediated regulation of quiescence and chronological life span.
This publication is also the subject of a newsfeed from the University
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Alien insects are increasingly being dispersed around the world through international trade, causing a multitude of negative environmental impacts and billions of dollars in economic losses annually. Border controls form the last line of defense against invasions, whereby inspectors aim to intercept and stop consignments that are contaminated with harmful alien insects. In Europe, member states depend on one another to prevent insect introductions by operating a first point of entry rule - controlling goods only when they initially enter the continent. However, ensuring consistency between border control points is difficult because there exists no optimal inspection strategy. For the first time, we developed a method to quantify the volume of agricultural trade that should be inspected for quarantine insects at border control points in Europe, based on global agricultural trade of over 100 million distinct origin-commodity-species-destination pathways. This metric was then used to evaluate the performance of existing border controls, as measured by border interception results in Europe between 2003 and 2007. Alarmingly, we found significant gaps between the trade pathways that should be inspected and actual number of interceptions. Moreover, many of the most likely introduction pathways yielded none or very few insect interceptions, because regular interceptions are only made on only a narrow range of pathways. European countries with gaps in border controls have been invaded by higher numbers of quarantine alien insect species, indicating the importance of proper inspections to prevent insect invasions. Equipped with an optimal inspection strategy based on the underlying risks of trade, authorities globally will be able to implement more effective and consistent border controls.
This publication is also the subject of a newsfeed from the University
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