New possibilities in the observation of nucleic acids by electron spectroscopic imaging

Delain, Etienne; Fourcade, A; Révet, Bernard; Mory, C.

doi:10.1051/mmm:0199200302-3017500

Cited by 18 publications

(17 citation statements)

References 21 publications

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“…In fact, several modes for filtering images and diffraction patterns, also called electron spectroscopic imaging (ESI) and diffraction (ESD), are offered by the insertion of such a filter lens, or of its fully magnetic substitute ~ filter. Their possibilities and prospects have been recently surveyed by Reimer et al [-13] in the field of materials science, and by Delain et al [14] for the observation of nucleic acids. The major advantage of this approach is that entire images are formed and detected in parallel, which makes it possible to acquire large sets of data (over 10 6 pixels) within a short exposure time.…”

Section: Instrumentation and Methods: A Historical Surveymentioning

confidence: 99%

Electron energy loss spectrometry mapping

et al. 1994

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Abstract. Among electron beam microanalytical techniques, electron energy loss spectrometry (EELS) offers unique advantages in terms of information content, sensitivity, limits of detection. This paper describes new methods and tools for acquiring families of spectra over many pixels on the specimen, i.e. spectrumimages, and for processing them. Applications in different fields of research, both in materials science and in life sciences, demonstrate the potential impact of the technique for characterizing nano-sized structures.Key words: electron microscopy, nanoanalysis, electron energy loss spectrum, image-spectrum aquisition and processing.Electron energy loss spectrometry (EELS) measures the energy loss suffered by high energy incident electrons transmitted through the specimen prepared as a thin foil. Its information content is very diversified. The low loss range, between 5 and 50 eV, reflects mostly the collective behaviour of the conduction electron gas through the appearance of plasmon peaks, the energy of which is determined by the average electron density. After some lengthy data analysis one can also have access to optical properties and to localized surface electronic properties. The high energy range, from 50 eV up to 1000 or 2000 eV, exhibits the core-edges associated with the excitation of inner-shell atomic levels. Its main interest is for elemental identification. Moreover the study of the fine structures on these edges offers fingerprints for the determination of site symmetry and for the evaluation of bond lengths.When recorded in the electron microscope, EELS data also contain spatial information [1], which is usually intended for chemical analysis. In essence, one makes a map of the spatial origin of chemically significant signals such as the characteristic core-edges and this technique complements the standard X-ray compositional imaging mode. However it constitutes only one aspect of the richness of the field of applications for EELS mapping. The present paper discusses recent progress in spatially resolved EELS and its use as a nanoanalytical tool, in which spectra can be acquired from many adjacent nanosized areas in a heterogeneous material and processed quantitatively.

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Section: Instrumentation and Methods: A Historical Surveymentioning

confidence: 99%

Electron energy loss spectrometry mapping

et al. 1994

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“…They were observed in the same microscope operated either in bright-field or in the electron spectroscopic imaging mode, obtained by selecting the inelastic electrons corresponding to the 04,5 edge of uranium. The resulting reverse image is highly contrasted and is devoid of phase contrast (19).…”

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confidence: 91%

“…Fur-DNA complexes containing 0.5 ug of DNA per ml, obtained without glutaraldehyde fixation, were deposited onto a grid covered with a thin carbon film previously activated by a glow-discharge in the presence ofpentylamine (18); they were then stained with 2% aqueous uranyl acetate, drained, and air dried. The observations were done in the annular dark-field mode in a Zeiss 902 EM, filtering out inelastically scattered electrons for enhanced contrast and resolution (19). Fur protein alone and Fur-DNA complexes obtained at a Fur/DNA ratio of 150 were negatively stained with uranyl acetate on carbon-coated grids rendered hydrophilic by a glow-discharge in air (in a MED010 Balzers apparatus).…”

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confidence: 99%

Observation of binding and polymerization of Fur repressor onto operator-containing DNA with electron and atomic force microscopes.

Cam

Frechon

Barray

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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“…The contrast is improved by chemical staining with heavy atoms including osmium, uranyl, lead, or iron. However, TEM analysis of individual macromolecular systems can be performed using either bright field or dark field mode, generally depending on negative or positive staining sample preparation, respectively . This is the case for nanoparticle polymersome characterization negatively stained, observed in bright field mode and for DNA, positively stained, observed in dark field mode …”

Section: Introductionmentioning

confidence: 99%

Dark Field Transmission Electron Microscopy Imaging for Biological and Soft Matter Systems

Ayache

Péchoux

Jaillard³

et al. 2016

Macromolecular Symposia

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International audienceIn this study, we present a new application of the transmission electron microscopy dark field mode for cell imaging. We have applied this imaging mode to two types of cellular systems: human HeLa cells to analyze molecular membrane systems and HC11 mouse mammary cells containing lipid molecule droplets. We have also studied a third macromolecular system, copolymer nanoparticles for the characterization of core-shell structures. We want to show the effective use of diffraction contrast, even on amorphous systems for increasing the image contrast and the signal/noise ratio. We discuss the TEM dark field advantages for the analysis of polymers and other macromolecular systems, including biological, systems compared to the bright field mode

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New possibilities in the observation of nucleic acids by electron spectroscopic imaging

Cited by 18 publications

References 21 publications

Electron energy loss spectrometry mapping

Electron energy loss spectrometry mapping

Observation of binding and polymerization of Fur repressor onto operator-containing DNA with electron and atomic force microscopes.

Dark Field Transmission Electron Microscopy Imaging for Biological and Soft Matter Systems

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