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Laser Doppler holographic microscopy in transmission: application to fish embryo imaging 
Auteur(s): Verrier N., Alexandre D., Gross M.
(Article) Publié:
Optics Express, vol. 22 p.9368 (2014)
Texte intégral en Openaccess : 
Ref HAL: hal-00970195_v1
PMID 24787825
Ref Arxiv: 1404.7781
DOI: 10.1364/OE.22.009368
WoS: 000335902200054
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
12 Citations
Résumé: We have extended Laser Doppler holographic microscopy to transmission geometry. The technique is validated with living fish embryos imaged by a modified upright bio-microcope. By varying the frequency of the holographic reference beam, and the combination of frames used to calculate the hologram, multimodal imaging has been performed. Doppler images of the blood vessels for different Doppler shifts, images where the flow direction is coded in RGB colors or movies showing blood cells individual motion have been obtained as well. The ability to select the Fourier space zone that is used to calculate the signal, makes the method quantitative.
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Delta-promoted filopodia mediate long-range lateral inhibition in Drosophila.
Auteur(s): de Joussineau Cyrille, Soule Jonathan, Martin Fernandez M., Anguille Christelle, Montcourrier Philippe, Alexandre D.
(Article) Publié:
Nature, vol. 426 p.555 - 559 (2003)
Texte intégral en Openaccess : 
Ref HAL: hal-01922148_v1
PMID 14654840
DOI: 10.1038/nature02157
WoS: 000186944300038
Exporter : BibTex | endNote
127 Citations
Résumé: Drosophila thoracic mechanosensory bristles originate from cells that are singled out from 'proneural' groups of competent epithelial cells. Neural competence is restricted to individual sensory organ precursors (SOPs) by Delta/Notch-mediated 'lateral inhibition', whereas other cells in the proneural field adopt an epidermal fate. The precursors of the large macrochaetes differentiate separately from individual proneural clusters that comprise about 20-30 cells or as heterochronic pairs from groups of more than 100 cells, whereas the precursors of the small regularly spaced microchaetes emerge from even larger proneural fields. This indicates that lateral inhibition might act over several cell diameters; it was difficult to reconcile with the fact that the inhibitory ligand Delta is membrane-bound until the observation that SOPs frequently extend thin processes offered an attractive hypothesis. Here we show that the extension of these planar filopodia--a common attribute of wing imaginal disc cells--is promoted by Delta and that their experimental suppression reduces Notch signalling in distant cells and increases bristle density in large proneural groups, showing that these membrane specializations mediate long-range lateral inhibition.
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Tail regression in Ciona intestinalis (Prochordate) involves a Caspase-dependent apoptosis event associated with ERK activation
Auteur(s): Chambon Jean-Philippe, Soule Jonathan, Pomiès Pascal, Fort Philippe, Sahuquet Alain, Alexandre D., Mangeat Paul-Henri, Baghdiguian Stephen
(Article) Publié:
Development (Cambridge, England), vol. 129 p.3105-14 (2002)
Texte intégral en Openaccess : 
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