Transient Stem-Loop Structure of Nucleic Acid Template May Interfere with Polymerase Chain Reaction through Endonuclease Activity of Taq DNA Polymerase
As a standard molecular biology technique, PCR uses DNA polymerase to detect, amplify and manipulate DNA targets. Due to its exponential amplification effect, the PCR can achieve a high sensitivity required to detect the detection of low abundance objectives. Therefore, it has become the method of choice for the majority of nucleic acid tests. In PCR reactions, the DNA models are first scrolled in simple strands, followed by a rapid temperature drop when transient intramolecular secondary structures may first form in single-stranded models due to reaction kinetics.
In this study, we have shown that adverse effects of PCR performance rod loop structures were directly related to their thermal stability. In addition, the fractions of intermediate PCR products with models with stable rod loop structures were significantly shorter than without. It has also been shown that during the duplex region of such structure during the PCR extension step, the taq adn polymerase endonuclease activity by its exonuclease activity of 5′– 3 ‘could digest a model strand, resulting in a running rod buckle structure and subsequent replication completion to produce truncated products. This work has provided new mechanistic perspectives on the complex nature of PCR’s analyzes, a frequently encountered but neglected aspect of this widely used technique.
Vitamin D Receptor Gene Polymorphisms Taq-1 and CDX-1 in Female Hair Loss
Ackground: Hair loss (FPHL) is an important cause of hair loss in adult women and has a major impact on the patient’s quality of life. It evolves progressive miniaturization of follicles that leads to a subsequent decrease in hair density, leading to non-cicatricic diffuse alopecia, with characteristic clinical, dermoscopic and histological schemes. The Vitamin D (VDR) receptor is expressed in follichank keratinocytes and dermal taste buds and that it demonstrates an important role in hair growth and hair cycle regulation. The VDR polymorphism has not been studied in depth in hair disorders, including FPHL.
Objective: To study the association between the polymorphism of VDR genes (CDX-1 and TAQ-1) and the FPHL to explore if these polymorphisms affect the occurrence of the disease or influence its clinical presentation.
Methods: A case control study was carried out on 30 patients with FPHL and 30 healthy substances with a 26-year-old woman as a control group. Degree of hair loss were evaluated by the Ludwig ranking. VDR, TAQ-1 and CDX-1 gene polymorphisms have been studied by a real-time polymerase chain reaction.
Results: CC Genotype, TC Genotype and T Allele of Taq-1 were more common in patients with FPHL than in the control group. They increased the risk of disease of 12.6, 2.1 and 2.9 folds, respectively. AA Genotype, GA Genotype and G Allele from CDX-1 were significantly more widespread among FPHL patients than in the control group. They increased the risk of disease of 7.5, 5.2 and 5.5 folds, respectively.
Conclusion: Taq-1 and CDX-1 can be considered as risk factors for FPHL. They can play a role in the persistence of diseases rather than in the initiation of the disease. This association can be explained by a failure of new anicane growth and a reduction in the proliferation of follicular stem cells. Other studies are recommended to confirm the current results.
Transient Stem-Loop Structure of Nucleic Acid Template May Interfere with Polymerase Chain Reaction through Endonuclease Activity of Taq DNA Polymerase
Tocking Taq Polymerase’s activity using the Triplex Like Aptamer structure of the clip
In nature, Allostery is the main approach to regulate processes and cell lanes. Inspired by nature, structure switching nanodetics are widely used in artificial biotechnologies. However, canonical aptamer structures in nanodavities generally adopt a duplex form, which limits flexibility and controllability. Here, a new regulatory strategy based on a Triplex (CLETS) clip (CLETS) aptamera structure has been proposed to change DNA polymerase activity via conformational changes. It has been shown that the activity of the polymerase could be adjusted by adjusting structure parameters or dynamic reactions, including moving strands or enzymatic digestion. Compared to the structure of the Duplex Aptamer, CLTAs have programmability, excellent affinity and efficiency of high discrimination. CLTAs have been successfully applied to distinguish unique basic incompatibles. The strategy expands the scope of the demand for triplex structures and has a potential for bioseensing and programmable nanomachines.
Cytomegalovirus (CMV) is a herpes virus spread all over the world that establishes latent infection after primary infection. This becomes a major problem in immunocompromised patients and in case of primary or reactivated infection during pregnancy. The CMV is the most common congenital infection and is the main infectious cause of sensational deafness and brain retardation. The inhibition of PCR by metal ions can be a serious challenge in the medical-legal DNA analysis process. Samples contaminated by different types of metal ions encountered in crime scenes include swabs of metal surfaces such as bullets, cartridge envelopes, weapons (including firearms and knives), metal wires and surfaces as well as bone samples containing calcium. The mechanism behind the impact of metal ions on the recovery of DNA, extraction and subsequent amplification is not completely understood. In this study, we evaluated the inhibitory effects of metals commonly encountered on the amplification of DNA.
The nine metals tested, zinc, tin, iron (II) and copper have been demonstrated for the highest inhibitory properties comprising IC50 values significantly less than 1 mm. In the second part of the study, three commercially available DNA polymerases have been tested for their susceptibility to the inhibition of metals. We found that Kod Polymerase was the most resistant to the inhibition of metals compared to Q5 and Taq polymerase.
Jordan
