EMCAT: An automatic image-processing system for electron-microscopic tomography

Author(s):  
Weiping Liu ◽  
John W. Sedat ◽  
David A. Agard

Any real world object is three-dimensional. The principle of tomography, which reconstructs the 3-D structure of an object from its 2-D projections of different view angles has found application in many disciplines. Electron Microscopic (EM) tomography on non-ordered structures (e.g., subcellular structures in biology and non-crystalline structures in material science) has been exercised sporadically in the last twenty years or so. As vital as is the 3-D structural information and with no existing alternative 3-D imaging technique to compete in its high resolution range, the technique to date remains the kingdom of a brave few. Its tedious tasks have been preventing it from being a routine tool. One keyword in promoting its popularity is automation: The data collection has been automated in our lab, which can routinely yield a data set of over 100 projections in the matter of a few hours. Now the image processing part is also automated. Such automations finish the job easier, faster and better.

2017 ◽  
Vol 372 (1726) ◽  
pp. 20160210 ◽  
Author(s):  
Michelle A. Dunstone ◽  
Alex de Marco

Cryo-electron tomography (cryo-ET) is a three-dimensional imaging technique that makes it possible to analyse the structure of complex and dynamic biological assemblies in their native conditions. The latest technological and image processing developments demonstrate that it is possible to obtain structural information at nanometre resolution. The sample preparation required for the cryo-ET technique does not require the isolation of a protein and other macromolecular complexes from its native environment. Therefore, cryo-ET is emerging as an important tool to study the structure of membrane-associated proteins including pores. This article is part of the themed issue ‘Membrane pores: from structure and assembly, to medicine and technology’.


1993 ◽  
Vol 88 (5) ◽  
pp. 402-406 ◽  
Author(s):  
Takashi MIKAMI ◽  
Hirotoshi MITAMURA ◽  
Shigeharu KANEMOTO ◽  
Shota TANIMOTO ◽  
Yoshinobu TSUCHIYA ◽  
...  

Author(s):  
Weiping Liu ◽  
Jennifer Fung ◽  
W.J. de Ruijter ◽  
Hans Chen ◽  
John W. Sedat ◽  
...  

Electron tomography is a technique where many projections of an object are collected from the transmission electron microscope (TEM), and are then used to reconstruct the object in its entirety, allowing internal structure to be viewed. As vital as is the 3-D structural information and with no other 3-D imaging technique to compete in its resolution range, electron tomography of amorphous structures has been exercised only sporadically over the last ten years. Its general lack of popularity can be attributed to the tediousness of the entire process starting from the data collection, image processing for reconstruction, and extending to the 3-D image analysis. We have been investing effort to automate all aspects of electron tomography. Our systems of data collection and tomographic image processing will be briefly described.To date, we have developed a second generation automated data collection system based on an SGI workstation (Fig. 1) (The previous version used a micro VAX). The computer takes full control of the microscope operations with its graphical menu driven environment. This is made possible by the direct digital recording of images using the CCD camera.


Author(s):  
Jo¨rg Schu¨tte ◽  
Sven Scholz

Railway and Public Guided Transit Properties often employ large numbers of video cameras to supervise critical areas and facilitate incident management. Capabilities of Central Control Staff is, however, limited to check the increasing number of CCTV images and so far automated image processing solutions had been insufficiently reliable. TelSys GmbH (a railway telematics company in Dresden, Germany) had therefore developed over the last seven years together with the University of Technology in Dresden and some public transport providers (subway of Berlin, subway of Prague) a robust solution to supervise automatically critical areas like tunnel entrances, station tracks or station platform edges. Also qualifications with German Railways and in Finland had been performed. The automatic image processing software reliably differentiates between trains (“permitted” objects) and objects that move from the platform into the tracks or move too close to otherwise prohibited areas. Object sizes, alarm times, reliability and safety requirements had been taken from the VDV 399 standard of the German Public Transport Operators Association. After years of reliability and safety research and demonstration the system is now in regular operation (stopping automatically incoming driverless trains if an object is detected in the track) and can be considered as the first safe video image processing system according to railway standards. Experiences, system architecture and principles as well as further development plans and planned demonstration installation in North America are discussed.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Shambhu Malleshappa Gowder ◽  
Jhinuk Chatterjee ◽  
Tanusree Chaudhuri ◽  
Kusum Paul

The analysis of protein structures provides plenty of information about the factors governing the folding and stability of proteins, the preferred amino acids in the protein environment, the location of the residues in the interior/surface of a protein and so forth. In general, hydrophobic residues such as Val, Leu, Ile, Phe, and Met tend to be buried in the interior and polar side chains exposed to solvent. The present work depends on sequence as well as structural information of the protein and aims to understand nature of hydrophobic residues on the protein surfaces. It is based on the nonredundant data set of 218 monomeric proteins. Solvent accessibility of each protein was determined using NACCESS software and then obtained the homologous sequences to understand how well solvent exposed and buried hydrophobic residues are evolutionarily conserved and assigned the confidence scores to hydrophobic residues to be buried or solvent exposed based on the information obtained from conservation score and knowledge of flanking regions of hydrophobic residues. In the absence of a three-dimensional structure, the ability to predict surface accessibility of hydrophobic residues directly from the sequence is of great help in choosing the sites of chemical modification or specific mutations and in the studies of protein stability and molecular interactions.


2017 ◽  
Vol 10 (03) ◽  
pp. 1750003 ◽  
Author(s):  
Shuang Zhang ◽  
Chengcai Leng ◽  
Hongbo Liu ◽  
Kun Wang ◽  
Jie Tian

Bioluminescence tomography (BLT) is a novel optical molecular imaging technique that advanced the conventional planar bioluminescence imaging (BLI) into a quantifiable three-dimensional (3D) approach in preclinical living animal studies in oncology. In order to solve the inverse problem and reconstruct tumor lesions inside animal body accurately, the prior structural information is commonly obtained from X-ray computed tomography (CT). This strategy requires a complicated hybrid imaging system, extensive post imaging analysis and involvement of ionizing radiation. Moreover, the overall robustness highly depends on the fusion accuracy between the optical and structural information. Here, we present a pure optical bioluminescence tomographic (POBT) system and a novel BLT workflow based on multi-view projection acquisition and 3D surface reconstruction. This method can reconstruct the 3D surface of an imaging subject based on a sparse set of planar white-light and bioluminescent images, so that the prior structural information can be offered for 3D tumor lesion reconstruction without the involvement of CT. The performance of this novel technique was evaluated through the comparison with a conventional dual-modality tomographic (DMT) system and a commercialized optical imaging system (IVIS Spectrum) using three breast cancer xenografts. The results revealed that the new technique offered comparable in vivo tomographic accuracy with the DMT system ([Formula: see text]) in much shorter data analysis time. It also offered significantly better accuracy comparing with the IVIS system ([Formula: see text]) without sacrificing too much time.


2002 ◽  
Author(s):  
Kevin I. C. Ho ◽  
Tung-Shou Chen ◽  
Hsing-Yi Su

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