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Introduction and Background
Published in Jay L. Nadeau, Introduction to Experimental Biophysics, 2017
Nucleotides (polymerize to form nucleic acids [DNA, RNA]). DNA is made of four nitrogenous bases: adenine, guanine, cytosine, and thymine (abbreviated A, G, C, and T). Adenine is shown in Figure 1.3c. A and G are purines, while T and C are pyrimidines (Figure 1.4). When the base is linked to a sugar (in the case of DNA, this sugar is deoxyribose; in the case of RNA, ribose), it is called a nucleoside: e.g., adenine becomes adenosine (in RNA) or deoxyadenosine (in DNA). Addition of one or more phosphate groups makes it a nucleotide. Short chains of A, C, G, and T nucleotides form oligonucleotides (if there are few, usually 20 or fewer bases) or polynucleotides (for longer chains). Oligonucleotides may be purchased from many suppliers and are inexpensive. As provided, they are single-stranded. However, DNA in nature is usually double-stranded, with A being complementary to T and C to G due to complementary hydrogen bonding (Figure 1.3c). Complementary oligonucleotides can be made to hybridize into double strands by simply heating them to 95°C and then allowing them to cool. However, if they are not fully complementary, the final double-stranded form is much less stable, and the strands can separate at relatively low temperatures. This fact forms the basis of much of molecular cloning and many types of biosensors.
Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Deoxyadenosine is a deoxyribonucleoside. It is a derivative of the nucleoside adenosine, differing from the latter by the replacement of a hydroxyl group (-OH) by hydrogen (-H) at the 2’ position of its ribose sugar moiety. Deoxyadenosine is the DNA nucleoside A, which pairs with deoxythymidine (T) in double-stranded DNA.
Preparation and evaluation of a nanoemulsion containing cordycepin and its protective effect on skin
Published in Journal of Dispersion Science and Technology, 2023
Hucheng Zhang, Lina Deng, Jun Yang, Guowei Yang, Haitao Fan, Yiqi Yin, Shuai Luo, Shuangshi Li, Linying Liu, Ming Yang
The pursuit of beauty has led to the use of cosmetics by millions of men and women worldwide. A cosmetic is a cocktail of chemicals that is intentionally applied to the skin for the purpose of promoting attractiveness or beautification. For centuries, Cordyceps mushrooms have been used in traditional Chinese medicine to treat diseases.[1,2] Advancements in pharmaceutical biotechniques have enabled many active ingredients, including cordycepin from Cordyceps species.[3–6] In 1950, cordycepin was first isolated from Cordyceps militais.[7] Since then, cordycepin structure and pharmacological activities have attracted much attention. Cordycepin, 3′-deoxyadenosine [9-(3-deoxy-β-D-ribofuranosyl) adenine] (Supplementary material, S1), is a purine nucleoside analogue. Cordycepin has a broad spectrum of biological activities, including anticancer, anti-oxidant, antimicrobial, antihyperuricemia, and anti-aging properties.[8–15] In the treatment of allergic inflammation, cordycepin reduces the expression of IL-13 and other inflammatory genes by inhibiting the expression of thymus stromal lymphopoietin.[16,17] Cordycepin is also an effective anti-inflammatory agent, [18,19] even in the treatment of inflammation-related diseases such as atopic dermatitis[20] and neuroinflammation.[21,22] Cordycepin can block damage caused by ultraviolet light, which constitutes its anti-oxidation and anti-aging properties.[23] However, the properties of cordycepin have not been examined in cosmetic applications.
Genotoxicity of quinone: An insight on DNA adducts and its LC-MS-based detection
Published in Critical Reviews in Environmental Science and Technology, 2022
Yue Xiong, Han Yeong Kaw, Lizhong Zhu, Wei Wang
HBQs can undergo Michael addition with nucleophilic amino groups on DNA to form DNA adducts. A quinone metabolite of pentachlorophenol (PCP) named tetrachloro-1,4-benzoquinone (TetraCBQ) is a reactive electrophilic reagent that can covalently form DNA adducts and further affect a series of life activities such as DNA transcription and replication (McLean et al., 1996). Through LC-MS analysis on a mixed solution of dG/deoxyadenosine (dA)/deoxycytidine (dC)/deoxythymidine (dT) with TetraCBQ (Nguyen et al., 2005) and dG with MBBQ/DBBQ (Lai et al., 2011), the stable adducts of dichloroquinone-nucleoside were generated (Figure 2). When it was exposed to ctDNA, TetraCBQ preferentially formed adducts with dG and dC (Arif et al., 2003; Vaidyanathan et al., 2007). In addition, when HBQs were incubated with both single-stranded and double-stranded oligonucleotides, adducts with the ratios of 1:1 and 1:2 were detected by ESI-MS/MS (Anichina et al., 2011). It can be deduced that HBQs bind with DNA through H-bonds and partially embedded non-covalent mechanisms. The affinity of different HBQs with oligonucleotides was in the order of TriCBQ≈DCMBQ < DCBQ≪DBBQ, and the tendency of interaction depended on the substitution degree of halogen of HBQs (Lai et al., 2011). Xingwei Guo et al. quantified the ambident electrophilicities of 2,5-DCBQ and unveiled the attacks pathways of C1-H, C2-Halogen, C3-H and C1-O. When amines attacked the 2,5-DCBQ, the C − H site/bond prone to be attacked at a higher rate than the chlorinated carbon to yield zwitterion, followed by a slower attack at the C2 site that led to nucleophilic substitution of the chloride (Guo & Mayr, 2014). As for dG and dC with two N nucleophilic sites, they were inclined to attack both C-H and C-halogen sites of HBQs to generate cyclic DNA adducts. At present, the single nucleotide adducts of HBQs and their intracellular production are yet to be fully verified.