10 research outputs found
Three-Dimensional, Tomographic Super-Resolution Fluorescence Imaging of Serially Sectioned Thick Samples
Three-dimensional fluorescence imaging of thick tissue samples with near-molecular resolution remains a fundamental challenge in the life sciences. To tackle this, we developed tomoSTORM, an approach combining single-molecule localization-based super-resolution microscopy with array tomography of structurally intact brain tissue. Consecutive sections organized in a ribbon were serially imaged with a lateral resolution of 28 nm and an axial resolution of 40 nm in tissue volumes of up to 50 µm×50 µm×2.5 µm. Using targeted expression of membrane bound (m)GFP and immunohistochemistry at the calyx of Held, a model synapse for central glutamatergic neurotransmission, we delineated the course of the membrane and fine-structure of mitochondria. This method allows multiplexed super-resolution imaging in large tissue volumes with a resolution three orders of magnitude better than confocal microscopy
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Understanding the rise of faculty-student coaching: an academic capitalism perspective
We examine the rise of coaching within management education to support student learning. We question the assumption that faculty-student coaching (FSC) is beneficial and propose that there may be some limitations in the use of FSC that have yet to be adequately acknowledged and discussed in the literature. In particular, we propose that there is currently insufficient evidence to conclude that coaching can produce knowledge acquisition and therefore ask why we persist in the use of FSC when we have limited evidence of its efficacy in delivering a core education outcome. We suggest that the theory of academic capitalism provides a useful, critical lens through which to view the growing trend in FSC, identifying that FSC may be utilized as a method of increasing student satisfaction, perceptions of value for money and as a useful marketing tool for business schools competing for students. However, academic capitalism may also explain the use of coaching via its ability to enhance the skills and attitudes of students, providing outcomes that are valued by students, employers and governments. We conclude our essay by providing recommendations to mitigate these proposed dangers and consequently maximise the effectiveness of coaching as a development tool in management education
A small pool of vesicles maintains synaptic activity in vivo
Chemical synapses contain substantial numbers of neurotransmitter-filled synaptic vesicles, ranging from approximately 100 to many thousands. The vesicles fuse with the plasma membrane to release neurotransmitter and are subsequently reformed and recycled. Stimulation of synapses in vitro generally causes the majority of the synaptic vesicles to release neurotransmitter, leading to the assumption that synapses contain numerous vesicles to sustain transmission during high activity. We tested this assumption by an approach we termed cellular ethology, monitoring vesicle function in behaving animals (10 animal models, nematodes to mammals). Using FM dye photooxidation, pHluorin imaging, and HRP uptake we found that only approximately 1–5% of the vesicles recycled over several hours, in both CNS synapses and neuromuscular junctions. These vesicles recycle repeatedly, intermixing slowly (over hours) with the reserve vesicles. The latter can eventually release when recycling is inhibited in vivo but do not seem to participate under normal activity. Vesicle recycling increased only to ≈5% in animals subjected to an extreme stress situation (frog predation on locusts). Synapsin, a molecule binding both vesicles and the cytoskeleton, may be a marker for the reserve vesicles: the proportion of vesicles recycling in vivo increased to 30% in synapsin-null Drosophila. We conclude that synapses do not require numerous reserve vesicles to sustain neurotransmitter release and thus may use them for other purposes, examined in the accompanying paper