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Food Interactions, Sirtuins, Genes, Homeostasis, and General Discussion
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
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).
The Emerging Role of Exosome Nanoparticles in Regenerative Medicine
Published in Harishkumar Madhyastha, Durgesh Nandini Chauhan, Nanopharmaceuticals in Regenerative Medicine, 2022
Zahra Sadat Hashemi, Mahlegha Ghavami, Saeed Khalili, Seyed Morteza Naghib
Other than EM, which meanly is used for direct observation of EVs morphology, different methods are used for their characterisation. As explained, exosomes can contain markers on their surface as their parent cells. The immuno-affinity-based approaches such as Enzyme-Linked Immunosorbent Assays (ELISA), Flow Cytometry, and antibody-coated magnetic beads rely on surface markers of EVs for their immuno-isolation and characterisation. Amongst these, the ELISA method has most commonly been applied for detection of EVs. The plates of ELISA kit could be coated by pan-exosome antibodies (anti-CD63 and anti-caveolin-1 melanoma-derived exosomes) to capture the exosomes existing in the samples (Logozzi et al. 2009; Khodashenas et al. 2019). As a high throughput approach of label-free protein analysis, the electrochemical sensing platforms and the plasmonic were combined with immuno-affinity methods (Contreras-Naranjo et al. 2017). However, EVs can be collected by their protein contents and applying conventional detection method, such as total protein analysis and western blots (Bradford assays, bicinchoninic acid (BCA)) (Khodashenas et al. 2019). Aside from the protein content, the nucleic acid contents (DNA, RNA, or miRNA) can be searched by PCR (polymerase chain reaction) or DNA sequencing methods (Eldh et al. 2012; Li et al. 2014; Zarovni et al. 2015).
Basic genetics and patterns of inheritance
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Errors in the sequence of nucleic acids of the DNA produce mutations in genes and often lead to genetic diseases. There are a variety of different kinds of mutations that can occur in genes. Some result in genetic disorders, while others may have no detrimental effect. The most common type of mutations include missense (single amino acid change), nonsense (insertion of stop codon with premature termination of translation), frameshift (insertion or deletion of nucleotides that alters downstream codons), splice site (incorrect splicing of introns), and promoter mutations (decreased transcription of mRNA). An expansion mutation occurs when there is insertion of many extra copies of a trinucleotide repeat; examples of disorders with this type of mutation are fragile X syndrome, Huntington disease, and myotonic dystrophy.
Development of amplification system for point-of-care test of nucleic acid
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Shaolei Huang, Jiageng Wu, Haozheng Dai, Runxin Gao, Hongyu Lin, Dongxu Zhang, Shengxiang Ge
NAT can be divided into three main steps which contains extraction, amplification and detection. Usually, the initial DNA concentration of samples is too low to be detected directly. Therefore, nucleic acid amplification is important to increase the nucleic acid exponentially to reach detectable level. In recent years, isothermal amplification techniques represented by LAMP and NASBA have developed rapidly, which have the advantages of high amplification efficiency, high specificity, short reaction time and low requirements for instruments (Yan et al. 2020, Lu et al. 2020), and are now able to be applied in clinical diagnosis. However, isothermal amplification technology still has some shortcomings, firstly, the primer design for isothermal amplification is complex, and the amplification process requires a variety of enzymes (Notomi et al. 2000), and the deployment of biological reagents is also difficult. Secondly, isothermal amplification is currently unable to achieve quantitative detection for clinical applications, the concentration of the virus is not accurate enough for doctors to monitor the effect of treatment and adjust the treatment plan.
Smartphone technology facilitates point-of-care nucleic acid diagnosis: a beginner’s guide
Published in Critical Reviews in Clinical Laboratory Sciences, 2021
Vinoth Kumar Rajendran, Padmavathy Bakthavathsalam, Peter L. Bergquist, Anwar Sunna
Indirect methods include several in vitro nucleic acid amplification techniques like PCR and isothermal amplification. Although direct methods are easy to implement and do not require additional steps, the nucleic acids targeted generally require amplification to obtain sufficient sensitivity [29]. Nucleic acid amplification tests take minute amounts of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), replicate them many times, and allow detection of low numbers of organisms while avoiding the need for culturing. The rapid turnaround time and high sensitivity and specificity make these PCR and isothermal nucleic acid amplification methods useful for rapid diagnosis of infectious diseases. A number of devices are available commercially and a description of their unique features, time for analysis and instrumentation required for amplification are summarized in Table 1. This review focuses on devices that are still largely in the developmental stage.
Bioresponsive polyplexes – chemically programmed for nucleic acid delivery
Published in Expert Opinion on Drug Delivery, 2018
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.