The Cell and Cell Division
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
Nucleic acids form the essential basis of DNA and RNA. These are made of the following three compounds: Bases: Nitrogenous ring compounds called purines (adenine and guanine) or pyrimidines [cytosine, thymine (DNA), or uracil (RNA)].Pentose sugars: Two types—ribose (β-D-ribose: RNA) and deoxyribose (β-d-2 deoxyribose: DNA).Phosphate: The phosphate bond is attached to the 5’ C hydroxyl group, and in a nucleic acid, it bonds to the 3’ C position of the adjacent sugar residue.
Food Interactions, Sirtuins, Genes, Homeostasis, and General Discussion
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
A gene, the basic physical and functional unit of heredity, is made up of deoxyribonucleic acid (DNA). (103–107). A gene is a sequence of nucleotides in a particular nucleic acid (104). The nucleotide is the structural unit of a nucleic acid. It is comprised of phosphoric acid, sugar (5-carbon), and a nitrogenous base. The chains of nucleotides in a nucleic acid are linked by 3′, 5′ phosphodiester linkages (104). Genes control identifiable traits of an organism. Genes are segments of DNA that contain the code for a specific protein that functions in one or more types of cells in the body (106). The information stored in DNA is arranged in hereditary units, now known as genes, that control identifiable traits of an organism. In the process of transcription, the information stored in DNA is copied into ribonucleic acid (RNA), which has three distinct roles in protein synthesis (107). Some genes contain all the information necessary to synthesize a protein (enzyme). However, many genes do not code for proteins (105). In humans, genes vary in size from a few hundred DNA bases to more than 2 million DNA bases (105). Humans have about 20,000 to 25,000 genes (105–106).
Cells, Tissues and Organs
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
The next category of intracellular organelles are ribosomes (Figure 2.4). These tiny granular structures consist of two unequal parts (one large and one small subunit) that fit together in order to manufacture proteins from amino acid building blocks using a ribonucleic acid (RNA) template from the nucleus. The name ribosome (ribo + some) is derived from ribo nucleic acid and the Greek word for body soma. Ribosomes are produced in a specialised part of the nucleus called the nucleolus and made from protein and RNA. We have already spent quite a lot of time poking around in the nucleus looking at DNA but what is RNA? In many ways it is very similar to DNA but it differs from its close relative in a number of important respects. Firstly, RNA is built from the sugar ribose instead of deoxyribose hence ribo nucleic acid instead of deoxyribonucleic acid (DNA). Secondly, DNA has a double helix and RNA consists of a single strand of nucleotides (bases). Thirdly, the nucleotide thymine (T) in DNA is replaced on the RNA strand by uracil (U) which also binds with adenine. Finally, RNA is able to transfer genetic material, needed for protein synthesis, from the nucleus to the ribosomes (also constructed from RNA) in the cytoplasm. This feature is extremely important for the maintenance of normal cellular activity.
Bioresponsive polyplexes – chemically programmed for nucleic acid delivery
Published in Expert Opinion on Drug Delivery, 2018
Simone Hager, Ernst Wagner
Many different extra- and intracellular steps and barriers exist in the systemic delivery of nucleic acids, making the whole delivery process very challenging. Furthermore, the different types of therapeutic nucleic acids have different demands on their carriers. Appropriate, efficient, and safe carrier systems are needed. In this context, non-viral, synthetic nanoformulations such as lipo- and polyplexes have come into focus. Imitation of the efficient, dynamic behavior of viruses can be achieved by incorporation of responsive, pre-programmed units into these non-viral delivery systems, which react to exogenous or endogenous triggers. Bioresponsive polyplexes sense changes in, for example, pH value, redox potential or enzyme activity, resulting in activation or exposure of functional domains within or in collapse of the nanoparticle. This facilitates programmed, timely delivery of nucleic acids to the desired, specific sites. Besides this biochemical targeting, bioresponsiveness can help to reduce cytotoxicity and improve the biocompatibility of cationic polymers. Combination of two and more responsive elements can help to increase both efficiency and specificity of the transfection process.
Relationship between functional Nrf2 gene promoter polymorphism and sperm DNA damage in male infertility
Published in Systems Biology in Reproductive Medicine, 2021
O. Sena Aydos, Yunus Yukselten, Dunya Aydos, Asuman Sunguroglu, Kaan Aydos
The effects of unbalanced ROS accumulation and accompanying oxidative stress on sperm parameters have been implied in other studies (Baker and Aitken 2005). Since the polyunsaturated fatty acid component of the plasma membranes is abundant and antioxidant enzyme activity is extremely low in the sperm cytoplasm, sperms are susceptible to higher ROS levels, which also causes DNA damage. The activation of lipid peroxidation cascades by stressed sperms multiplies ROS, which further impairs sperm function. As a result of the oxidation of sulfhydryl groups by ROS, the phosphorylation of axonal proteins declines, impairing sperm motility. Hence, as the peroxidation of phospholipids in the sperm membrane increases, sperm motility falls because of the decrease in membrane fluidity (Barati et al. 2020). DNA damage causes several molecular changes in the structure of nucleic acid chains. The end results are alterations in gene-transcription and transduction pathways, degraded telomeric DNA, replication errors, genomic instability, and deviation from CG to AT (Barati et al. 2020). Sperms exposed to oxidative DNA damage that degenerated are absorbed either during spermatogenesis or transport from the epididymis, decreasing sperm count. Sperm count as well as forward motility and normal morphology are inversely related with a high DNA fragmentation index (Venkatesh et al. 2011; Aydos et al. 2015). This level of DNA damage impair seminal parameters as we observed a significant decrease in both concentration and progressive motility parallel to a rising TCS.
Characterization of biological peculiarities of the radioprotective activity of double-stranded RNA isolated from Saccharomyces сerevisiae
Published in International Journal of Radiation Biology, 2020
Genrikh S. Ritter, Valeriy P. Nikolin, Nelly A. Popova, Anastasia S. Proskurina, Polina E. Kisaretova, Oleg S. Taranov, Tatiana D. Dubatolova, Evgenia V. Dolgova, Ekaterina A. Potter, Svetlana S. Kirikovich, Yaroslav R. Efremov, Sergey I. Bayborodin, Margarita V. Romanenko, Maria I. Meschaninova, Aliya G. Venyaminova, Nikolay A. Kolchanov, Mikhail A. Shurdov, Sergey S. Bogachev
Using HAP chromatography, a fraction of the RNA with eluting properties of double-stranded form of nucleic acids was isolated. Further experiments univocally indicated this fraction, constituting 1–3% of the total RNA used, to be responsible for the radioprotective effects in all biological tests. Moreover, the effective dose LD100/30 in the case of the total RNA was 7–10 mg per mouse, while in the case of double-stranded form, only 160 μg of the preparation per mouse, which is 60 times less, provided exactly the same radioprotective effect. In a series of experiments, it was shown that administration of the double-stranded nucleic acid preparation 60–30 min prior to irradiation completely eliminates the harmful effect of γ-radiation, ensuring the survival of 80–100% of experimental animals.