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Published in Chad A. Mirkin, Spherical Nucleic Acids, 2020
Nathaniel L. Rosi, Chad A. Mirkin
Nanotubes and nanowires are being explored as new signal transduction motifs in the electrical detection of DNA [99-103] as they have for the detection of gases [104-107], small molecules [108], and proteins (vide infra) [20, 103, 109, 110]. For example, Lieber and colleagues demonstrated that silicon nanowires functionalized with PNA can be used for real-time, label-free detection of DNA [99]. In their assay the conductance of a PNA-functionalized silicon nanowire bridging two electrodes is measured in the presence of target DNA and mutant DNA with three consecutive base deletions. Introduction of target DNA into the assay caused a rapid and immediate change in conductance, while the effect of mutant DNA was negligible. Furthermore, the conductance changes scale with target concentration, and target DNA can be detected at concentrations as low as 10 fM. In the case of nanotubes, Lieber and colleagues showed that specific sequences of kilobase-size DNA can be detected using single-walled carbon nanotube (SWNT) atomic force microscopy (AFM) probes [100]. Specifically, they marked particular sequences along the DNA strand with streptavidin-labeled complementary DNA probes and then used AFM to identify the streptavidin and thus the location of the target sequences. This technique enabled the detection of specific haplotypes that code for genetic disorders.
Cellular Biology in Tissue Engineering
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
Histocompatibility antigens responsible for the most vigorous allograft rejection reactions are located on the major histocompatibility complex (MHC). They are inherited as haplotypes or two half sets (one from each parent). This makes a person half identical to each of his or her parents with respect to the MHC complex. Every person expresses 6 MHC1 alleles (HLA-A, HLA-B, HLA-C—one from each parent) and at least 6 MHC2 alleles (HLA-DQ, HLA-DP, HLA-DR—one from each parent). The MHC molecules are divided into two classes. The class I molecules are normally expressed on all nucleated cells, whereas the class II molecules are expressed only on the professional antigen-presenting cells (APCs), such as dendritic cells, activated macrophages, and B cells. The physiological function of the MHC molecules is to present antigenic peptides to T cells. The class I molecules are responsible for presenting antigenic peptides from within the cell (e.g., antigens from the intracellular viruses, tumor antigens, self-antigens) to CD8 T cells. The class II molecules present extracellular antigens such as extracellular bacteria to CD4 T cells. The activation of T cells is dependent on two essential signals. In addition to the bond formed by the MHC and the TCR, there is also the need for a secondary co-stimulatory response. This secondary response occurs when a bond is formed between the molecule B7 and CD28 on APCs and Helper T cells, respectively.
Associations between Genetic Polymorphisms and Heart Rate Variability
Published in Herbert F. Jelinek, David J. Cornforth, Ahsan H. Khandoker, ECG Time Series Variability Analysis, 2017
Anne Voigt, Jasha W. Trompf, Mikhail Tamayo, Ethan Ng, Yuling Zhou, Yaxin Lu, Slade Matthews, Brett D. Hambly, Herbert F. Jelinek
The alternative method for discovery of pathological genetic changes is the candidate gene approach. This method involves the genotyping of key genes, using SNP haplotypes, then testing the phenotype of the SNP haplotypes. The candidate gene approach takes advantage of information on gene location and function of the protein product. Positive association or linkage of the gene to the disease implies they are correlated.
Association between Bone Morphogenetic Protein 2 Gene Polymorphisms and Skeletal Fluorosis of The Brick-tea Type Fluorosis in Tibetans and Kazakhs, China
Published in International Journal of Environmental Health Research, 2021
Qun Lou, Ning Guo, Wei Huang, Liaowei Wu, Mengyao Su, Yang Liu, Xiaona Liu, Bingyun Li, Yanmei Yang, Yanhui Gao
Due to the limited function and genetic information of SNPs, analyzing the relationship between candidate genes and disease using single-site SNP is often not comprehensive. Linkage disequilibrium (LD) refers to a non-random combination of different genetic markers (Zhang et al. 2002). Due to the limited population size and complex population history, this non-random combination is ubiquitous in the genome. Under normal circumstances, LD cannot extend far, and it only appears between genetic markers that are close together. As a stable, high-density genetic marker, SNP has become the best genetic marker in LD research. An important feature of common genetic variation is the strong correlation between adjacent SNPs. The adjacent related SNPs on the same chromosome are specifically combined to form a haplotype. The haplotype as a genetic marker has higher polymorphism and statistical efficiency than a single SNP (Joshua et al. 2001). So, haplotype information is an essential ingredient in many analyses of fine-scale molecular-genetic data. There are some results that to search for the association between genes in SNPs and diseases show that the haplotype may cause the pathogenesis and the staging(Carrillo-Moreno et al. 2019; Sun et al. 2019). Although it has been reported that Rs235764 G/G genotype could increase the risk of vertebral fracture (Tranah et al. 2008), the function of Rs235764 polymorphism is unknown. Hence, it is possible that this SNP is in LD with a functional variant (Tranah et al. 2008). In our study, Rs235764 polymorphism had no LD with other SNPs, just a high LD of Rs996544 and Rs235739 was found in the subjects. So, we further analyzed the haplotype of Rs996544 and Rs235739 aiming at finding the association with brick-tea-type SF. Unexpectedly, none of four haplotypes had association with SF in all subjects. In conclusion, our results do not support an association between the BMP2 polymorphism and brick-tea-type SF.