Electron microscopy of DNA complexes with synthetic oligopeptides

1992 ◽  
Vol 5 (2) ◽  
pp. 193-207 ◽  
Author(s):  
Yuri Y. Vengerov ◽  
Timur E. Semenov
Keyword(s):  
Electron Microscopy ◽  
Dna Complexes

Observation of Fast Sedimenting, Replicating Bacteriophage T7 DNA by Negative Staining

1980 ◽  
Vol 38 ◽  
pp. 538-539
Author(s):  
P. Serwer
Keyword(s):  
Electron Microscopy ◽  
Cytochrome C ◽  
Dna Packaging ◽  
Negative Staining ◽  
Bacteriophage T7 ◽  
Dna Complexes ◽  
Sufficient Detail ◽  
Protein Monolayer

To package the DNA of bacteriophage T7, a preformed, DNA-free capsid (capsid I) with an envelope thicker than the envelope of bacteriophage T7:(a) binds DNA, (b) converts to a capsid (capsid II) with a bacteriophage-like envelope prior to packaging DNA and (c) draws in DNA (1). During attempts to understand T7 DNA packaging, complexes of capsids with mature T7 DNA and complexes of capsids with longer than mature, linear T7 DNA have been isolated (2). Objects with capsid-like dimensions were observed on a fast sedimenting, replicating complex of T7 DNA (100S+ DNA) prepared for electron microscopy using a protein monolayer-shadowing technique (3). This procedure for preparation of specimens does not, however, reveal sufficient detail to rigorously identify an object as a capsid. To better visualize objects bound to 100S+ T7 DNA, this DNA has been prepared for electron microscopy using the aqueous technique for the negative staining of capsid-DNA complexes more recently described (4) (the DNA is coated with cytochrome c and is revealed in an extended configuration).

scholarly journals Ultrastructural Analysis of DNA Complexes During Transfection and Intracellular Transport

2003 ◽  
Vol 51 (9) ◽  
pp. 1237-1240 ◽  
Author(s):  
Régis Cartier ◽  
Maria Velinova ◽  
Cathleen Lehman ◽  
Bettina Erdmann ◽  
Regina Reszka
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Intracellular Transport ◽  
Ultrastructural Analysis ◽  
Cell Entry ◽  
Dna Complexes ◽  
Simple Method ◽  
Transmission Electron ◽  
Internalization Process ◽  
Entry Mechanism

We present a simple method based on transmission electron microscopy that allows investigation of the early steps of polyplex-mediated transfection without the use of labeled DNA. The ultrastructural analysis showed internalization of 0.2–1-μm aggregates composed of 30–50-nm subunits. In addition, new details of the internalization process were revealed, suggesting an unspecific cell entry mechanism of large DNA aggregates.

scholarly journals Gyrase . DNA complexes visualized as looped structures by electron microscopy.

1983 ◽  
Vol 258 (7) ◽  
pp. 4612-4617
Author(s):  
C L Moore ◽  
L Klevan ◽  
J C Wang ◽  
J D Griffith
Keyword(s):  
Electron Microscopy ◽  
Dna Complexes

Atomic Force and Electron Microscopy of High Molecular Weight Circular DNA Complexes with Synthetic Oligopeptide Trivaline

2000 ◽  
Vol 17 (4) ◽  
pp. 687-695 ◽  
Author(s):  
Larissa P. Martinkina ◽  
Dmitry V. Klinov ◽  
Alexander A. Kolesnikov ◽  
Vyacheslav Yu. Yurchenko ◽  
Sergey A. Streltsov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Dna Complexes ◽  
Circular Dna ◽  
Atomic Force

scholarly journals Polycationic graft copolymers of poly(N-vinylpyrrolidone) as non-viral vectors for gene transfection

2009 ◽  
Vol 7 (3) ◽  
pp. 532-541 ◽  
Author(s):  
Yun-Hai Liu ◽  
Xiao-Hong Cao ◽  
Dao-Feng Peng ◽  
Wen-Yuan Xu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transfection Efficiency ◽  
Graft Copolymers ◽  
Gene Transfection ◽  
Favorable Effect ◽  
Dna Complexes ◽  
Free Radical Copolymerization ◽  
Transmission Electron

AbstractNovel graft copolymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with N-vinylpyrrolidone (NVP) were designed and synthesized by the free radical copolymerization of DMAEMA with precursor polymers of vinyl-functionalized poly(N-vinylpyrrolidone) (PVP). The ability of the PVP- grafted copolymers to bind and condense DNA was confirmed by ethidium bromide displacement assay, agarose gel electrophoresis and transmission electron microscopy. The presence of PVP in the copolymers had a favorable effect on the biophysical properties of polymer/DNA complexes. Colloidal stable complexes obtained from the copolymer systems, were shown to be separate, uniformly spherical nanoparticles by transmission electron microscopy. The approximate diameter of the complexes was 150–200 nm, as determined by dynamic light scattering studies. These results confirm an important role played by the PVP grafts in producing compact stable DNA complexes. The ζ-potential measurements revealed that the incorporation of the PVP grafts reduced the positive surface charge of polymer/DNA complexes. The cytotoxicity of the copolymers decreased with an increasing fraction of PVP. Furthermore, in vitro transfection experiments with these copolymers showed improved ability of transfection in cell culture, demonstrating an important role for PVP grafts in enhancement of the transfection efficiency.

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