Equipment for serial-section EM

点击翻译按钮获取中文摘要

My NSERC program investigates simple systems of nerve cells in model species of invertebrates. I increasingly use my Discovery grant to examine the circuits of identified nerve cells identified from series of electron micrographs by computer-aided three-dimensional reconstruction methods. Currently I am investigating the olfactory system of the fruit fly, other brain regions in the fly, and the central nervous system of the tadpole of the common sea squirt, distantly related to vertebrate animals like ourselves. My lab is world expert in these electron microscopic approaches and their applications in these and related species, and we will progressively analyse the synaptic circuits of different brain regions, as part of an endeavour to understand the mechanism of behaviour. The first step is to unravel the wiring diagrams of identified brain regions, and electron microscopy is essential for this task. Anatomical wiring diagrams then form the basis for genetic dissection and other studies that assay circuit function. We reconstruct nerve cell circuits from long uninterrupted series of images, and for this need a new ultramicrotome and diamond knives that can cut reliably at 40nm. Cutting suitable series of sections is thus the basis of all our work. Our abilities in these technically demanding procedures attract many collaborations and visiting trainees, as well as recruit our own graduate and postdoc HQP. Our external collaborations both enrich and accelerate my NSERC program at Dalhousie, as well as provide good exposure to HQP. For continued progress I urgently need to replace an ailing ultramicrotome that promises to die on us; a yet older NSERC machine purchased 28 years ago no longer cuts ultrathin sections, and I lack an alternative instrument elsewhere that is available for dedicated use. The equipment will be used mainly by HQP and technical staff to cut EM series, for graduate or postdoctoral research that is also assisted by undergraduate helpers, and by visitors who come to my lab to engage in this work and learn its methods. A new ultramicrotome is now essential for my lab to remain ahead in this type of research, and should give a further 10 or more years of service.