scholarly journals In Situ Unzipping of Long, High Molecular Weight DNA in Solid State Nanopores

2021 ◽  
Vol 120 (3) ◽  
pp. 273a
Author(s):  
Ravipa Losakul ◽  
Dayana E. Tobar ◽  
Akira Pimenov ◽  
Aracely Gutierrez ◽  
Robin Schipper ◽  
...  
Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 584
Author(s):  
Rui Dang ◽  
Liqiu Ma ◽  
Shengguo Zhou ◽  
Deng Pan ◽  
Bin Xia

Ultra-high molecular weight polythene (UHMWPE), with outstanding characteristics, is widely applied in modern industry, while it is also severely limited by its inherent shortcomings, which include low hardness, poor wear resistance, and easy wear. Implementation of feasible protection on ultra-high molecular weight polythene to overcome its shortcomings would be of significance. In the present study, amorphous carbon (a-C) film was fabricated on ultra-high molecular weight polythene (UHMWPE) to provide good protection, and the relevant growth mechanism of a-C film was revealed by controlling carbon plasma currents. The results showed the in situ transition layer, in the form of chemical bonds, was formed between the UHMWPE substrate and the a-C film with the introduction of carbon plasma, which provided strong adhesion, and then the a-C film continued epitaxial growth on the in situ transition layer with the treatment of carbon plasma. This in situ growth of a-C film, including the in situ transition layer and the epitaxial growth layer, significantly improved the wetting properties, mechanical properties, and tribological properties of UHMWPE. In particular, good protection by in situ growth a-C film on UHMWPE was achieved during sliding wear.


PROTOPLASMA ◽  
1987 ◽  
Vol 141 (2-3) ◽  
pp. 139-148 ◽  
Author(s):  
Christine Mederic ◽  
Odile Bertaux ◽  
J. D. Rouzeau ◽  
R. Valencia

1992 ◽  
Vol 38 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Ken F. Jarrell ◽  
David Faguy ◽  
Anne M. Hebert ◽  
Martin L. Kalmokoff

High molecular weight DNA was readily isolated from all methanogens treated, as well as from thermophilic anaerobic eubacteria, by grinding cells frozen in liquid N2, prior to lysis with SDS. DNA can subsequently be purified by the usual phenol–chloroform extractions. The procedure yields DNA readily cut by restriction enzymes and suitable for oligonucleotide probing, as well as for mole percent G + C content determination by thermal denaturation. The method routinely yields DNA of high molecular weight and is an improvement over DNA isolation methods for many methanogens, which often involve an initial breakage of the cells in a French pressure cell. Key words: methanogens, archaebacteria, archaea, DNA isolation.


2013 ◽  
Vol 21 (9) ◽  
pp. 965-970 ◽  
Author(s):  
Hong-Jo Park ◽  
Jihun Kim ◽  
Yongsok Seo ◽  
Junho Shim ◽  
Moon-Yong Sung ◽  
...  

1993 ◽  
Vol 71 (9-10) ◽  
pp. 488-500 ◽  
Author(s):  
Valerie M. Weaver ◽  
Boleslaw Lach ◽  
P. Roy Walker ◽  
Marianna Sikorska

Three chemically distinct serine, but not cysteine, protease inhibitors (phenylmethylsulphonyl fluoride, N-tosyl-L-phenylalanylchloromethyl ketone and 3,4-dichloroisocoumarin) prevented, in a dose-dependent manner, the characteristic apoptotic internucleosomal DNA cleavage (DNA ladder) typically observed in thymocytes in response to dexamethasone and teniposide VM-26. This effect was not the result of a direct inhibition of the Ca2+, Mg2+-dependent endonuclease, since oligonucleosomal DNA cleavage occurred in the presence of these inhibitors in isolated nuclei. The proteolytic step occurred at a very early stage of apoptosis, and preincubation of thymocytes with the inhibitors before dexamethasone or teniposide VM-26 were added irreversibly suppressed ladder formation. This implied that the cellular effector(s) of these compounds preexisted and were not resynthesized in response to the inducers of apoptosis. Serine protease inhibitors also suppressed apoptotic cell shrinkage and complete nuclear collapse, suggesting that these morphological changes were directly related to internucleosomal fragmentation of DNA. However, the serine protease inhibitors did not prevent high molecular weight DNA cleavage (> 50 kilobases) that preceded the ladder formation and thymocytes still died by apoptosis. This supported the view that internucleosomal DNA cleavage, considered to be the biochemical marker of apoptosis, might in fact be a late and dispensable step and that the newly described high molecular weight DNA cleavage might be a better indicator of apoptosis.Key words: serine protease, apoptosis, internucleosomal DNA fragmentation, high molecular weight DNA cleavage, protease inhibitors.


2019 ◽  
Author(s):  
Rasmus Dam Wollenberg ◽  
Brian Strehlow ◽  
Astrid Schuster

This protocol was used to extract high molecular weight DNA from the sponge (porifera) Halichondria panicea. This protocol contains slight modifications from that presented in Ausubel et al (1995). References: Ausubel, F.; Brent, R.; Kingston, R.; Moore, D.; Seidman, J.G.; Smith, J.;Struhl, K. Short Protocols in Molecular Biology(1995), 3rd ed., Unit 2.1: page 2-3


1975 ◽  
Vol 149 (1) ◽  
pp. 289-291 ◽  
Author(s):  
G M Blackburn ◽  
P E Taussig

Anthracene becomes covalently bound to high-molecular-weight DNA in mammalian tissue culture as a result of irradiation at 365 nm after the incubation of cells with the hydrocarbon. At high radiation doses, the extent of binding exceeds one hydrocarbon molecule per 103 bases, and is lethal. At low radiation doses, much decreased binding is observed, but a majority of cells remain viable and can be recultured.


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