Stefan Clerens

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A neuropeptide was isolated from a frog brain extract by HPLC purification and characterized by mass spectrometry. This 26-aa neuropeptide, which belongs to the RFamide peptide family, was designated 26RFa, and its primary structure was established as VGTALGSLAEELNGYNRKKGGFSFRF-NH2. Research in databases revealed the presence of sequences homologous to frog(More)
Department of Biology, Laboratory for Developmental Biology, Botany Institute, KULeuven, Kasteelpark Arenberg 31, B–3001 Leuven, Belgium (W.V.d.E., R.V., L.V.R., A.V.L.); Department of Biology, Laboratory of Neuro-endocrinology and Immunological Biotechnology, Zoological Institute, KULeuven, Naamsestraat 59, B–3000 Leuven, Belgium (S.C.); and National(More)
The cloning of two highly homologous chicory (Cichorium intybus var. foliosum cv Flash) fructan 1-exohydrolase cDNAs (1-FEH IIa and 1-FEH IIb) is described. Both isoenzymes could be purified from forced chicory roots as well as from the etiolated "Belgian endive" leaves where the 1-FEH IIa isoform is present in higher concentrations. Full-length cDNAs were(More)
* Fructans are believed to contribute to cold and drought tolerance in several plant families (Poaceae, Asparagaceae and Asteraceae), but it is not clear why the ability to accumulate these polymers is found in some genera (e.g. Triticum) but not in others (e.g. Oryza). * As fructan biosynthesis enzymes (FBEs) evolved from vacuolar invertases (VINs), we(More)
One of the landmarks of Alzheimer's disease are neurofibrillary tangles (NFT) in the brain. NFT mainly consist of a hyperphosphorylated form of the protein tau, which is responsible for stabilisation of the neuronal cytoskeleton by microtubule binding and is unable to function properly in its hyperphosphorylated form. Glycogen synthase kinase-3beta(More)
About 15% of flowering plants accumulate fructans. Inulin-type fructans with β(2,1) fructosyl linkages typically accumulate in the core eudicot families (e.g. Asteraceae), while levan-type fructans with β(2,6) linkages and branched, graminan-type fructans with mixed linkages predominate in monocot families. Here, we describe the unexpected finding that(More)
Inulin-type fructans are the simplest and most studied fructans and have become increasingly popular as prebiotic health-improving compounds. A natural variation in the degree of polymerization (DP) of inulins is observed within the family of the Asteraceae. Globe thistle (Echinops ritro), artichoke (Cynara scolymus), and Viguiera discolor biosynthesize(More)
The response of the hippocampal proteome to expression of mutant proteins present in familial forms of Alzheimer's disease (AD) was studied using transgenic rats. These animals carry both the amyloid precursor protein Swedish and 717 mutation (APP(SW+717)) as well as the presenilin 1 Finnish mutation (PS1(FINN)). This transgenic rat model displays(More)
A software tool, Sweet Substitute, is described, which assists tandem mass spectrometry (MS/MS)-based glycosylation characterization from within a tryptic digest. The algorithm creates a virtual nanoelectrospray-quadrupole time-of-flight style-MS/MS spectrum of any user-defined N-linked glycan structure. An empirical peak height modeling routine is(More)
Fructans, beta2-1 and/or beta2-6 linked polymers of fructose, are produced by fructosyltransferases (FTs) from sucrose. They are important storage carbohydrates in many plants. Fructan reserves, widely distributed in plants, are believed to be mobilized via fructan exohydrolases (FEHs). The purification, cloning, and functional characterization of a 6-FEH(More)