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Regional differences in the lateral mobility properties of plasma membrane lipids were studied in unfertilized and fertilized Xenopus eggs by fluorescence photobleaching recovery (FPR) measurements. Out of a variety of commonly used lipid probes only the aminofluorescein- -1abelled fatty acids HEDAF (5-(N-hexadecanoyl)- aminofluorescein) and TEDAF (5-(N-tetradecanoyl)-aminofluorescein) appear to distribute itself in the plasma membrane. Under all experimental conditions used these molecules show partial recovery upon photobleaching, indicating the existence of lipidic microdomains.

Diakonia, Bd. 4 Nr. 4 (1969): Diakonia, Band 4, Heft 4

Diakonia, Bd. 4 Nr. 4 (1969): Diakonia, Band 4, Heft 4

Diakonia, Bd. 4 Nr. 4 (1969): Diakonia, Band 4, Heft 4

Diakonia, Bd. 4 Nr. 4 (1969): Diakonia, Band 4, Heft 4

Contains fulltext : 100592.pdf (Publisher’s version ) (Open Access) Radboud Universiteit Nijmegen, 13 november 2012 Promotores : Zoelen, E.J.J. van, Gielen, C.C.A.M. Co-promotor : Theuvenet, A.P.R. 190 p.

Contains fulltext : 74880.pdf (Publisher’s version ) (Open Access) RU Radboud Universiteit Nijmegen, 12 januari 2010 Promotor : Zoelen, E.J.J. van 243 p.

Contains fulltext : 32053_humaexani.pdf (Publisher’s version ) (Open Access) Contains fulltext : 72481.pdf (Publisher’s version ) (Open Access) Radboud Universiteit Nijmegen, 17 januari 2008 Promotor : Pruijn, G.J.M. Co-promotores : Zoelen, E.J.J. van, Heck, A.J.R. van, Hendriks, W.J.A.J. 140 p.

Contains fulltext : 30023.pdf (Publisher’s version ) (Open Access) The frequently occurring bone disorder osteoporosis is characterized by a strong increase in bone fracture risk, caused by a dramatically disturbed balance in the activity of the cells that degrade bone (osteoclasts) and cells that synthesize new bone (osteoblasts). Therapies against osteoporosis are currently based on inhibition of osteoclast activity in order to reduce the amount of bone resorption. An alternative strategy would be to stimulate new bone formation by enhancing the activity of osteoblasts. The main objective of this thesis was to identify genes of which expression and function are specifically associated with the differentiation of mesenchymal stem cells into osteoblasts. Therefore, we used microarray-based gene expression profiling to study the transcriptome of differentiating osteoblasts during in vitro cell culture as well as in their physiological context during skeletogenesis. The analyses revealed many genes of which expression in osteoblasts had not previously been detected. Novel markers of osteoblast differentiation and bone development were identified as well as putative in vivo target genes of the transcription factor Runx2 which is a key regulator of skeletal development. One of the markers identified encodes the protein Wif1 (Wnt Inhibitory Factor 1), which was shown to be specifically expressed in osteoblasts during embryonic development. Typically, genes encoding antagonists of the Wnt signalling pathway were strongly expressed during late stages of osteoblast differentiation and implicate an important role of Wnt antagonism in the maturation of osteoblasts. Given the role of Wnt signalling in the maintenance of bone mass, this class of proteins may be potential drug targets to treat bone disorders. This thesis shows that the combination of microarray technology and bioinformatic analyses has provided new possibilities to the understanding of bone biology. Consequently, our studies have contributed to a more detailed knowledge on osteoblast differentiation and provide focus points to develop strategies that will prevent and treat bone disorders. Radboud University, Applied Biology, 04 juni 2007 Promotores : Olijve, W., Zoelen, E.J.J. van Co-promotor : Dechering, K.J. 264 p.

Contains fulltext : 30196.pdf (Publisher’s version ) (Open Access) Radboud university, Cell Biology, 11 juni 2007 Promotor : Zoelen, E.J.J. van 113 p.

Contains fulltext : 19562.pdf (Publisher’s version ) (Open Access) The DNA sequences of many genomes have been elucidated in the last years. The challenge now is to predict first the genotype and then the phenotype from the genomic sequences. To predict expression patterns of the genes located on the genome, not only regulation at the level of transcription, but also at the level of translation is important. To obtain more information about regulation of transcription, the promoter and its regulatory elements need to be mapped. In this thesis a conventional search for known and active regulatory elements in the B2-crystallin promoter was performed. For the intergenic region between aB-crystallin and HspB2, an alternative approach was taken to determine which elements are likely to be important for gene regulation, and the evolutionary conservation of sequence elements in this region was studied. Alignments of this region of many species lead to the confirmation of importance of known regulatory elements and the finding of new sites. A good example of regulation of gene expression mediated by regulation of translation, is translation after stress. During and after heat shock, cap-dependent translation is inhibited, while cap-independent translation can still take place. After heat shock translation of (s)Hsps is increased, these (s)Hsps are thought to protect cells from stress. We show that two of the sHsps, aB-crystallin and Hsp27 protect cap-dependent, but not cap-independent translation after heat shock. Inhibition of translation is thought to be mediated by a decrease in activity of the translation factors. However, the protection of translation mediated by sHsps does not seem to affect translation factors directly, but overexpression of aB-crystallin seems to increase the dispersal of stress granules that contain the stalled translation initiation complexes. We propose that aB-crystallin, probably together with other Hsps, resolubilizes the stress granule components and that translational thermotolerance is a cooperative effect of different Hsps. RU, Biochemistry, 07 januari 2005 Promotores : Jong, W.W.W. de, Zoelen, E.J.J. van Co-promotor : Lubsen, N.H. 142 p.

Contains fulltext : 32614.pdf (Publisher’s version ) (Open Access) RU Radboud Universiteit Nijmegen, 26 oktober 2005 Promotores : Olijve, W., Zoelen, E.J.J. van 156 p.