A novel exosome biogenesis mechanism: multivesicular structures budding and rupturing at the plasma membrane

AbstractExosomes are small vesicles secreted by the cells, which mediate intercellular signalling and systemic physiological processes. Exosomes are known to originate from the intraluminal vesicles of the multivesicular endosome that fuses with the plasma membrane. We found that the non-small cell lung cancer (NSCLC) cell lines, HCC15 and A549, secreted exosomes with typical morphology and protein contents. Unexpectedly, transmission electron microscopy images indicated that the cells formed multivesicular structures that protruded from the plasma membrane and ruptured to release the exosomes. There were smooth multivesicular structures surrounded by an ordinary looking membrane, multivesicular structures coated by an electron dense layer with regular spacing pattern, and intermediate forms that combined elements of both. Electron microscopy images suggested that exosomes are release from these structures by burst events and not by the conventional fusion process. The molecular details of this novel mechanism for membrane association, deformation and fusion is to be unveiled in the future.

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A Transmission Electron Microscopical Investigation of Phase Transformations in TiNi

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001446 ◽

1980 ◽

Vol 38 ◽

pp. 340-341

Author(s):

P. Moine ◽

G. M. Michal ◽

R. Sinclair

Keyword(s):

Electron Microscopy ◽

Phase Transformations ◽

Applied Stress ◽

Structural Changes ◽

Microscopical Investigation ◽

Temperature Range ◽

Transmission Electron ◽

Electron Microscopical ◽

Diffraction Effects ◽

Microscopy Images

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.

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Green Synthesis of Feather-Shaped MoS2/CdS Photocatalyst for Effective Hydrogen Production

International Journal of Photoenergy ◽

10.1155/2013/247516 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 4

Author(s):

Yang Liu ◽

Hongtao Yu ◽

Xie Quan ◽

Shuo Chen

Keyword(s):

Electron Microscopy ◽

Hydrogen Production ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance ◽

Sulfur Source ◽

X Ray ◽

Transmission Electron ◽

Microscopy Images ◽

Effective Hydrogen ◽

Better Than

MoS2/CdS photocatalyst was fabricated by a hydrothermal method for H2production under visible light. This method used low toxic thiourea as a sulfur source and was carried out at 200°C. Thus, it was better than the traditional methods, which are based on an annealing process at relatively high temperature (above 400°C) using toxic H2S as reducing agent. Scanning electron microscopy and transmission electron microscopy images showed that the morphologies of MoS2/CdS samples were feather shaped and MoS2layer was on the surface of CdS. The X-ray photoelectron spectroscopy testified that the sample was composed of stoichiometric MoS2and CdS. The UV-vis diffuse reflectance spectra displayed that the loading of MoS2can enhance the optical absorption of MoS2/CdS. The photocatalytic activity of MoS2/CdS was evaluated by producing hydrogen. The hydrogen production rate on MoS2/CdS reached 192 μmol·h−1. This performance was stable during three repeated photocatalytic processes.

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Error Quantification in Strain Mapping Methods

Microscopy and Microanalysis ◽

10.1017/s1431927607070407 ◽

2007 ◽

Vol 13 (5) ◽

pp. 320-328 ◽

Cited By ~ 16

Author(s):

Elisa Guerrero ◽

Pedro Galindo ◽

Andrés Yáñez ◽

Teresa Ben ◽

Sergio I. Molina

Keyword(s):

Electron Microscopy ◽

Geometric Phase ◽

Step Response ◽

Strain Mapping ◽

Error Quantification ◽

Transmission Electron ◽

Mapping Techniques ◽

Microscopy Images ◽

Real State

In this article a method for determining errors of the strain values when applying strain mapping techniques has been devised. This methodology starts with the generation of a thickness/defocus series of simulated high-resolution transmission electron microscopy images of InAsxP1−x/InP heterostructures and the application of geometric phase. To obtain optimal defocusing conditions, a comparison of different defocus values is carried out by the calculation of the strain profile standard deviations among different specimen thicknesses. Finally, based on the analogy of real state strain to a step response, a characterization of strain mapping error near an interface is proposed.

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