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Visualization of miniSOG Tagged DNA Repair Proteins in Combination with Electron Spectroscopic Imaging (ESI)
Published on: September 24, 2015
Elemental mapping of DNA chains by energy-filtering TEM
Kazuhiro Aoyama1, Rena Matsumoto, Syuichi Oka
1National Institute of Advanced Industrial Science and Technology, International Patent Organism Depositary, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan. kaoyama@jp.feico.com
Journal of Electron Microscopy
|August 2, 2003
Summary
Researchers developed a phosphorus mapping technique using energy-filtering transmission electron microscopy (EF-TEM) to visualize DNA chains. This method, enhanced by image merging, overcomes low signal detection for clearer DNA molecule observation.
Area of Science:
- Materials Science
- Biophysics
- Microscopy
Background:
- Direct visualization of DNA chains is challenging due to low signal levels in microscopy.
- Preserving the native structure of DNA, such as plasmid superstructures, is crucial for accurate observation.
- Existing phosphorus mapping techniques may suffer from background noise and signal attenuation.
Purpose of the Study:
- To develop and optimize a method for detecting and mapping DNA chains using energy-filtering transmission electron microscopy (EF-TEM).
- To enhance the visibility of DNA molecules by improving signal-to-noise ratio and preserving structural integrity.
- To identify critical factors for successful phosphorus mapping of DNA.
Main Methods:
- Utilized energy-filtering transmission electron microscopy (EF-TEM) for phosphorus mapping of DNA.
- Employed a three-window method combined with an image-merging system to enhance signal detection.
- Implemented rapid-freezing and freeze-drying techniques for specimen preparation to preserve DNA structure.
- Investigated the critical role of ultra-thin carbon-supporting films (< 2 nm) for signal transmission.
Main Results:
- The image-merging system was essential for observing DNA chains, which were undetectable with single images due to low signal.
- Preservation of plasmid superstructure using rapid-freezing and freeze-drying facilitated easier assignment of DNA molecules.
- Ultra-thin carbon-supporting films (< 2 nm) were identified as a critical factor for obtaining high-quality mapping images.
- The three-window method showed potential errors in background subtraction due to imprecise spectral data.
Conclusions:
- Phosphorus mapping with EF-TEM, particularly when combined with image merging and optimized specimen preparation, is a viable method for DNA chain detection.
- Ultra-thin support films are paramount for successful high-resolution elemental mapping of biological molecules.
- Further hardware improvements are recommended to enhance the quality of phosphorus mapping images and reduce background errors.
