The screencast on Ultra-Short Cantilevers (USC) for High Speed AFM (HS-AFM) and video rate Atomic Force Microscopy held by Mathieu Burri has just reached the 1000 views mark. Congratulations Mathieu!
The Ultra-Short Cantilevers series combines very small cantilevers capable of resonating in the MHz regime and a very sharp and wear resistant tip and is dedicated to High-Speed AFM (HS-AFM). The Ultra-Short Cantilevers series consists of six different types of probes which cover the complete range of high speed scanning applications, from non-contact mode to contact mode, from measurements in air to measurements in liquid.
More information such as high speed videos, an image gallery and a regularly updated reference list of scientific articles on high speed AFM can be found on the dedicated website: https://www.highspeedscanning.com/ . You can also find references to scientific articles mentioning the use of NanoWorld USC AFM probes on the NanoWorld blog.
If you haven’t seen the USC screencast yet have a look at:
NanoWorld ULTRA-SHORT CANTILEVERS for High-Speed AFM
A Chinese Version of this screencast is also available:
The Endosomal Sorting Complex Required for Transport-III (ESCRT-III) is part of a conserved membrane remodeling machine. ESCRT-III employs polymer formation to catalyze inside-out membrane fission processes in a large variety of cellular processes, including budding of endosomal vesicles and enveloped viruses, cytokinesis, nuclear envelope reformation, plasma membrane repair, exosome formation, neuron pruning, dendritic spine maintenance, and preperoxisomal vesicle biogenesis.*
How membrane shape influences ESCRT-III polymerization and how ESCRT-III shapes membranes is yet unclear.*
In the article “Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation” Aurélie Bertin, Nicola de Franceschi, Eugenio de la Mora, Sourav Maity, Maryam Alqabandi, Nolwen Miguet, Aurélie di Cicco, Wouter H. Roos, Stéphanie Mangenot, Winfried Weissenhorn and Patricia Bassereau describe how human core ESCRT-III proteins, CHMP4B, CHMP2A, CHMP2B and CHMP3 are used to address this issue in vitro by combining membrane nanotube pulling experiments, cryo-electron tomography and Atomic Force Microscopy.*
The authors show that CHMP4B filaments preferentially bind to flat membranes or to tubes with positive mean curvature.*
The results presented in the article cited above underline the versatile membrane remodeling activity of ESCRT-III that may be a general feature required for cellular membrane remodeling processes.*
The authors provide novel insight on how mechanics and geometry of the membrane and of ESCRT-III assemblies can generate forces to shape a membrane neck.*
Figure 1 from «Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation” by Aurélie Bertin et al.: CHMP4-ΔC flattens LUVs and binds preferentially to flat membranes or to membranes with a positive mean curvature. 1a CHMP4B-ΔC spirals observed by HS-AFM on a lipid bilayer. Scale bar: 50 nm. Please refer to the full article for the complete figure: https://rdcu.be/b5rOe
*Aurélie Bertin, Nicola de Franceschi, Eugenio de la Mora, Sourav Maity, Maryam Alqabandi, Nolwen Miguet, Aurélie di Cicco, Wouter H. Roos, Stéphanie Mangenot, Winfried Weissenhorn and Patricia Bassereau Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation Nature Communications volume 11, Article number: 2663 (2020) DOI: https://doi.org/10.1038/s41467-020-16368-5
Open Access The article “ Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation “ by Aurélie Bertin, Nicola de Franceschi, Eugenio de la Mora, Sourav Maity, Maryam Alqabandi, Nolwen Miguet, Aurélie di Cicco, Wouter H. Roos, Stéphanie Mangenot, Winfried Weissenhorn and Patricia Bassereau is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Ceramides are central intermediates of
sphingolipid metabolism that also function as potent messengers in stress
signaling and apoptosis. Progress in understanding how ceramides execute their
biological roles is hampered by a lack of methods to manipulate their cellular
levels and metabolic fate with appropriate spatiotemporal precision.*
In the
article “Optical manipulation of sphingolipid biosynthesis using
photoswitchable ceramides” Matthijs Kol, Ben Williams, Henry Toombs-Ruane,
Henri G Franquelim, Sergei Korneev, Christian Schroeer, Petra Schwille, Dirk
Trauner, Joost CM Holthuis and James A Frank report on clickable, azobenzene-containing ceramides, caCers, as
photoswitchable metabolic substrates to exert optical control over sphingolipid
production in cells.*
They combine atomic force microscopy on model bilayers with metabolic tracing studies in cells, and demonstrate that light-induced alterations in the lateral packing of caCers lead to marked differences in their metabolic conversion by sphingomyelin synthase and glucosylceramide synthase. These changes in metabolic rates are instant and reversible over several cycles of photoswitching. The findings described in the article disclose new opportunities to probe the causal roles of ceramides and their metabolic derivatives in a wide array of sphingolipid-dependent cellular processes with the spatiotemporal precision of light.*
The High-speed AFM in AC mode described in the article was done with NanoWorld Ultra-Short CantileversUSC-F0.3-k0.3 with a typical stiffness of 0.3 N/m. The AFM cantilever oscillation was tuned to a frequency of 100–150 kHz and the amplitude kept below 10 nm. The scan rate was set to 25–150 Hz. Images were acquired at 256 × 256 pixel resolution. All measurements were performed at room temperature. The force applied on the sample was minimized by continuously adjusting the set point and gain during imaging. Height, error, deflection and phase-shift signals were recorded and images were line-fitted as required.*
Figure 2 b from “ Optical manipulation of sphingolipid biosynthesis using photoswitchable ceramides “ by Matthijs Kol et al. : Photo-isomerization of caCers affects membrane fluidity and lipid domain structure in supported lipid bilayers. (b) Atomic force microscopy of supported lipid bilayers ( SLBs )prepared as in (a). Isomerization of caCer-3 (top) and caCer-4 (bottom) to cis with UV-A light (365 nm) resulted in a fluidification inside the Lo domains, as indicated by the appearance of small fluid Ld lakes and an increased Ld/Lo area ratio. This effect was reversed on isomerization back to trans with blue light (470 nm), marked by a drop in the Ld/Lo area ratio. Scale bars, 2 μm. (c) Time-course plotting the normalized Lo area over multiple 365/470 nm irradiation cycles for caCer-3 (top) and caCer-4 (bottom). Please refer to https://doi.org/10.7554/eLife.43230.007 for the full figure.
*Matthijs Kol, Ben Williams, Henry Toombs-Ruane, Henri G Franquelim, Sergei Korneev, Christian Schroeer, Petra Schwille, Dirk Trauner, Joost CM Holthuis, James A Frank Optical manipulation of sphingolipid biosynthesis using photoswitchable ceramides eLife 2019;8:e43230 DOI: 10.7554/eLife.43230 https://doi.org/10.7554/eLife.43230.001 https://doi.org/10.7554/eLife.43230.007
Open Access The article “Optical manipulation of sphingolipid biosynthesis using photoswitchable ceramides “ by Matthijs Kol, Ben Williams, Henry Toombs-Ruane, Henri G Franquelim, Sergei Korneev, Christian Schroeer, Petra Schwille, Dirk Trauner, Joost CM Holthuis and James A Frank is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
