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This movie (larger version) shows the development of a Drosophila embryo from early embryonic stages through to creation of a larva. A histone-GFP has been used to label every cell nuclei while a cytoplasmic mCherry has been used to label a segmentally repeated neural progenitor cell and all of its progeny. The researchers aim is to identify individual cells as they are born from the progenitor and track them as they differentiate into neurons.
These images are from Dr Holly Ironfield's experiments using CAIC's 2-photon excitation fluorescence microscope. This project, led Dr Matthias Landgraf, is part of the Neural Network Development Group of the Zoology Department.
The imaging was performed on a scanning 2-photon excitation fluorescence microscope. In this experiment 4 embryos were imaged sequentially, each every 2.5 minutes for 15 hours. The localised nature and longer wavelengths of 2-photon excitation result in deeper imaging and relatively low bleaching compared to single photon excitation.
This is a time-lapse imaging of a 55 hours post-fertilization transgenic zebrafish embryo during 24 hours. Here RFP expression is driven under the control of atoh7 promoter, labeling all retinal ganglion cells (RGCs) in the retina. We can clearly observe RGC axons projecting out of the retina inside the brain and finally reaching their target in the tectum, where they start to branch and make synapses. The researchers aim to study the molecular mechanisms regulating these events by combining genetic approaches and long-term high resolution imaging.