Highlights from Biological Applications
Applications in Stimulated Emission Depletion Microscopy: Localization of a Protein Toxin in the 5 Endoplasmic Reticulum Following Retrograde Transport by C Herrera, NJ Mantis and R Cole, Microsc Microanal 22(6) (2016) 1113–19
Some plant and bacterial toxins, including cholera and ricin toxin, exploit a specifi c type of transport (retrograde) to gain entry into host cells. Here we demonstrate the use of new imaging technology, super- resolution stimulated emission depletion (STED) microscopy, combined with live-cell imaging, to visualize ricin toxin within a sub-cellular organelle complex, the endoplasmic reticulum (ER). T ere is a 52% (0.09 versus 0.19 μ m) improvement in resolution obtained by STED, as compared with conventional confocal microscopy (CM). T is improved resolution provides a more accurate determi- nation of the amount of ricin that had traffi cked to the ER. We present a protocol that offers the possibility of using live-cell imaging and STED microscopy to study the traffi cking of biological toxins as the route through retrograde traffi cking pathways. T is breakthrough opens a new door to study mechanisms such as ricin traffi cking. A knowledge of ricin trafficking and how subcellular compartments interact with the toxin is essential in understanding fundamental cellular processes such as retrograde transport.
Materials Applications
Analytical Multimode Scanning and Transmission Electron Imaging and Tomography of Multiscale Structural Architectures of Sulfur Copolymer-Based Composite Cathodes for Next Generation High-Energy Density Li-S Batteries by VP Oleshko, AA Herzing, CL Soles, JJ Griebel, WJ Chung, AG Simmonds, and J Pyun, Microsc Microanl 22(6) (2016) 1198–21
Poly(sulfur-random-(1,3-diisopropenylbenzene) copolymers synthesized via inverse vulcanization represent an emerging class of electrochemically active polymers recently used in cathodes for Li-S batteries, capable of realizing enhanced capacity retention (1005 mAh/g at 100 cycles) and lifetimes of over 500 cycles. T e composite cathodes are organized in complex hierarchical 3D architectures (see fi gure), which contain several components and are challenging to understand and characterize using any single technique. Multimode analytical S/(T)EM and EDX/EEL spectros- copies coupled with multivariate statistical analysis and tomography were applied to explore origins of the cathode enhanced capacity retention. We found that replacing the elemental sulfur with organosulfur copolymers improves the compositional homogeneity and compatibility between carbons and sulfur-containing domains down to sub-5 nm length scales resulting in (a) intimate wetting of nanocarbons by the copolymers at interfaces; (b) the creation of 3D percolation networks of conductive pathways involving graphitic-like outer shells of aggregated carbons; (c) concomitant improvements in the stability with preserved meso- and nanoscale porosities required for effi cient charge transport.
62 doi: 10.1017/S1551929516001255
Three-dimensional reconstruction generated from a series collected with STED and CM microscopy. STED imaging here shows ER (blue) and locations where ricin and ER are together (cyan). Arrows correspond to ricin particles that are not localized with the ER. Scale bar = 15 µm.
Tilt-angle electron tomography of a poly(S-r-DIB10%)-based cathode powder using Cs probe-corrected STEM. The reconstructed 3D view of the agglomerated cathode fragment displaying two poly(S-r-DIB10%) copolymer microparticles colored in blue and green. The copolymer particles are surrounded by aggregated conductive C65 carbons colored in yellow, which form random percolation conductive networks and extended pore structures.
www.microscopy-today.com • 2017 March
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