Introduction of additional nucleobases into the double helix

2011 ◽  
Author(s):  
Poul Nielsen ◽  
Charlotte S. Madsen ◽  
Anna S. Jorgensen ◽  
Sarah Witzke ◽  
Khalil I. Shaikh ◽  
...  
Keyword(s):  
Double Helix

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

Electron microscopic assays of restriction endonuclease cutting, exonuclease digestion, and hybridization

1984 ◽  
Vol 42 ◽  
pp. 686-687
Author(s):  
Mark Hannibal ◽  
Jacob Varkey ◽  
Michael Beer
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Restriction Endonuclease ◽  
Double Helix ◽  
Test Material ◽  
Electron Microscopic ◽  
Exonuclease Iii ◽  
Dna Molecule ◽  
Linear Molecules ◽  
Exonuclease Digestion

Workman and Langmore have recently proposed a procedure for isolating particular chromatin fragments. The method requires restriction endonuclease cutting of the chromatin and a probe, their digestion with two exonucleases which leave complimentary single strand termini and low temperature hybridization of these. We here report simple electron microscopic monitoring of the four reactions involved.Our test material was ϕX-174 RF DNA which is cut once by restriction endonuclease Xho I. The conversion of circles to linear molecules was followed in Kleinschmidt spreads. Plate I shows a circular and a linear DNA molecule. The rate of cutting is shown in Figure 1.After completion of the endonuclease cutting, one portion of the DNA was treated with exonuclease III, an enzyme known to digest the 3' terminals of double helical DNA. Aliquots when examined in the electron microscope reveal a decreasing length of double helix and increasing bushes at the ends.

DNA Inspirited Rational Construction of Nonconventional Luminophores with Efficient and Color-Tunable Afterglow

2020 ◽  
Author(s):  
Yunzhong Wang ◽  
Saixing Tang ◽  
Yating Wen ◽  
Shuyuan Zheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Rational Design ◽  
Room Temperature ◽  
Double Helix ◽  
Mechanical Grinding ◽  
Room Temperature Phosphorescence ◽  
Color Tunable ◽  
Potential Applications ◽  
Rational Construction ◽  
Double Helix Structure ◽  
Made In

<div>Persistent room-temperature phosphorescence (p-RTP) from pure organics is attractive </div><div>due to its fundamental importance and potential applications in molecular imaging, </div><div>sensing, encryption, anticounterfeiting, etc.1-4 Recently, efforts have been also made in </div><div>obtaining color-tunable p-RTP in aromatic phosphors5 and nonconjugated polymers6,7. </div><div>The origin of color-tunable p-RTP and the rational design of such luminogens, </div><div>particularly those with explicit structure and molecular packing, remain challenging. </div><div>Noteworthily, nonconventional luminophores without significant conjugations generally </div><div>possess excitation-dependent photoluminescence (PL) because of the coexistence of </div><div>diverse clustered chromophores6,8, which strongly implicates the possibility to achieve </div><div>color-tunable p-RTP from their molecular crystals assisted by effective intermolecular </div><div>interactions. Here, inspirited by the highly stable double-helix structure and multiple </div><div>hydrogen bonds in DNA, we reported a series of nonconventional luminophores based on </div><div>hydantoin (HA), which demonstrate excitation-dependent PL and color-tunable p-RTP </div><div>from sky-blue to yellowish-green, accompanying unprecedentedly high PL and p-RTP </div><div>efficiencies of up to 87.5% and 21.8%, respectively. Meanwhile, the p-RTP emissions are </div><div>resistant to vigorous mechanical grinding, with lifetimes of up to 1.74 s. Such robust, </div><div>color-tunable and highly efficient p-RTP render the luminophores promising for varying </div><div>applications. These findings provide mechanism insights into the origin of color-tunable </div><div>p-RTP, and surely advance the exploitation of efficient nonconventional luminophores.</div>

The two greatest discoveries of two centuries - the nuclein and the double helix of DNA

Biomics ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 259-265
Author(s):  
G.A. Gerashchenkov ◽  
R.R. Garafutdinov ◽  
An.Kh. Baymiev ◽  
B.R Kuluev ◽  
Al.Kh. Baymiev ◽  
...  
Keyword(s):  
Double Helix

Spies, Secrets, and Papistry

2018 ◽  
Author(s):  
Rosamund Oates
Keyword(s):  
Double Helix ◽  
Divine Punishment ◽  
The Law ◽  
Missionary Church

This chapter examines the double helix of Matthew’s political and pastoral roles. He saw the northern Church as a missionary Church, and, like his contemporaries in Ireland, came to see prosecution as a powerful weapon in the struggle to end support for Catholicism. This led him to stress the importance of the law, alongside preaching and hospitality, as a tool of reformation. This chapter shows that Matthew’s persecution of Catholics was driven by his belief in the urgency of edifying reform as well as his fear of divine punishment. Matthew also played an important role in Anglo-Scottish relations in the last decade of Elizabeth’s reign. Anticipating James VI of Scotland’s succession to the English throne, he coordinated spy networks for Robert Cecil, negotiated border treaties, and oversaw James VI/I peaceful entry into England in 1603.

Equality, Liberty, and Education

2019 ◽  
Author(s):  
Daniel Kiel
Keyword(s):  
Education Reform ◽  
Double Helix ◽  
Compulsory Education ◽  
Education Law ◽  
Student Diversity ◽  
American Education ◽  
Law And Policy ◽  
Educational Challenges ◽  
The Future ◽  
1960S And 1970S

This chapter traces the arc of American education, describing how the tension between liberty and equality has shaped education law and policy every step of the way. The chapter begins by exploring the origins of American education, including the equality-minded adoption of compulsory education and common schools and the liberty-minded desire for parents to control elements of their children’s education. Next, the chapter expands to consideration of equality and liberty in the education of groups. This includes the equality revolutions of the 1960s and 1970s during which schooling became more inclusive of multiple groups of students, and also the liberty-based backlash to those revolutions pursuing greater local control and self-determination. The chapter then highlights the liberty and equality-based tensions impacting contemporary education reform, such as the standards and choice movements. Finally, the chapter looks to the future, arguing that advances in technology, increasing student diversity, and unprecedented flux in the structure of American education will force continued balancing of the values of liberty and equality. Ultimately, the chapter argues that these core democratic impulses—liberty and equality—form a double helix at the core of many of the conflicts in American education law and policy and that management of the relationship between them will continue to drive how Americans respond to educational challenges of the future.

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