scholarly journals Proteomics: Challenges, Techniques and Possibilities to Overcome Biological Sample Complexity

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Kondethimmanahalli Chandramouli ◽  
Pei-Yuan Qian
Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.


2021 ◽  
Vol 20 (8) ◽  
Author(s):  
Wooyeong Song ◽  
Marcin Wieśniak ◽  
Nana Liu ◽  
Marcin Pawłowski ◽  
Jinhyoung Lee ◽  
...  

2020 ◽  
Vol 415 ◽  
pp. 286-294
Author(s):  
Hassan Hafez-Kolahi ◽  
Shohreh Kasaei ◽  
Mahdiyeh Soleymani-Baghshah
Keyword(s):  

1997 ◽  
Vol 3 (S2) ◽  
pp. 1081-1082
Author(s):  
I. Angert ◽  
W. Jahn ◽  
K.C. Holmes ◽  
R.R. Schröder

Understanding the contrast formation mechanism in the EM is one of the prerequisites for artefact-free reconstruction of biological structures from images. We found that the normally used correction of contrast formation applied to zero energy loss filtered images corrupted spatial resolution. Therefore the contribution of contrast formed by inelastic electrons was reconsidered, including partial coherence of inelastically scattered electrons and lens aberrations of the microscope. Based on this, a complete description of the zero-loss contrast transfer function (CTF) is now possible.We used tobacco mosaic virus (TMV), a biological sample known at atomic resolution, for definition of optimum CTF-parameters to reconstruct defocus series from an EFTEM LEO 912. CTF theory as known so far describes image contrast in the weak phase approximation as a linear sum of amplitude and phase contrast. The contribution of amplitude contrast (ratio of amplitude to phase contrast A/P) was determined to be between 7% and 5 % for unfiltered images and 12-14 % for zero-loss filtered images. However, in a filter microscope we remove electrons from the image, so we expect a higher amplitude contrast than in non-filtered images.


2020 ◽  
Vol 24 ◽  
pp. 101002 ◽  
Author(s):  
Tássia Venga Mendes ◽  
Lidiane Silva Franqui ◽  
Mariane Gonçalves Santos ◽  
Célio Wisniewski ◽  
Eduardo Costa Figueiredo

2012 ◽  
Vol 91 (1) ◽  
pp. 1-42 ◽  
Author(s):  
Lena Chekina ◽  
Dan Gutfreund ◽  
Aryeh Kontorovich ◽  
Lior Rokach ◽  
Bracha Shapira
Keyword(s):  

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