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Aijalon Shantavia Bettis
[10] Josef Schmee and Wayne Nelson. Estimates and approximate confidence limits for (log) normal life distributions from singly censored samples by maximum likelihood. Technical report, DTIC Document, 1977.
Awardee and Student:
Dr. Emmanuel Appiah is an Assistant Professor with research interests in differential equations, time-to-event processes, mathematical statistics, integrable system, data science and mathematics education Edgar R. Mendoza is a sophomore, majoring in chemical engineering.
Monitoring DNA Interactions with Small Ring Polycyclic Aromatic Hydrocarbons
Introduction
Aijalon Shantavia Bettis
Mentor: Harshica Fernando Chemistry Department, College of Arts and Sciences
Polycyclic aromatic hydrocarbons (PAHs) are a group of more than 100 chemicals, also called polynuclear aromatic hydrocarbons. You can be exposed to polycyclic aromatic hydrocarbons by 1) ingesting or swallowing food that contains them, 2) inhaling or breathing fumes or smoke, or 3) touching food that contains PAHs. Exposure to some PAHs can cause less serious issues such as irritation of the eyes and or breathing passages as well as more serious issues, such as cancer. Consumers, cigarette smokers, and infants are at high risk of being exposed to PAHs.
Materials and Methods
The Ct-DNA was purchased from Worthington Biomedical Corp, NJ. 9, 10 bis-phenyl ethynyl anthracene was obtained from Sigma Chemical Company. All other chemicals and solvents such as TCPO and hydrogen peroxide were of analytical grade. Initially, Tris-HCl buffer at pH = 7.4 was prepared. Ct-DNA was dissolved in Tris-HCl buffer by stirring overnight at 40C. The purity of the DNA was measured by observing the absorbance ratio at 260 and 280. A ratio of 1.80 confirmed the purity of the DNA. The stock solution of anthracene was prepared by weighing 0.0035 g of the solid and dissolving in 2.0 ml of ethanol. The interaction of Ct-DNA with the fluorophore 9, 10 bisphenylethnylanthracene was monitored by small additions of 5.0 microliters of the Ct-DNA to a prepared mixture of TCPO, H2O2, and the fluorophore. The interaction of the Ct-DNA with the fluorophore was also compared to those interactions of the Ct-DNA with graphene oxide. The DNA concentration was calculated based on !!"# =6600&$% '( $% . The interactions were monitored using a Shimatzu UV-Vis spectrometer. In the UV experiments, the wavelength was scanned from 200 to 600 nm, and in the fluorescence experiments, excitation and emission wave lengths were set to 350 and 425 nm. Blank experiments were carried out using the Tris-HCl buffer solution.
Results and Discussion: Fluorescence results - From each fluorescence analysis we observed that the absorbance and the intensity changed with small additions of 5.0 microliters of the PAH solution. The first figure is an overlay graph of the addition of 9,10 diphenyl anthracene to the Ct-DNA. The second figure is the overlay graph of the addition of phenanthrene to the Ct-DNA. The last image is a plot of all five fluorophores with concentration plotted with the intensity.
Figure 1. Addition of 9, 10 diphenyl anthracene. Figure 6. Additions of phenanthrene.
Figure 7. All five fluorophores. Conclusion: Our results show that 9, 10 bisphenylethnylanthracene and the other fluorophores indeed exhibit an interaction with Ct-DNA. The nature of the interaction still needs to be identified. Future work will include kinetics and continued use of the fluorimeter.
References
Nishi, K., Isobe, S., Zhu, Y., & Kiyama, R. (2015). Fluorescence-Based Bioassays for the detection and evaluation of FOOD MATERIALS. Sensors, 15(10), 25831-25867. doi:10.3390/s151025831 Polycyclic Aromatic Hydrocarbons (PAHs): Your Environment, Your Health | National Library of Medicine. (n.d.). Retrieved from https://toxtown.nlm.nih.gov/chemicals-and-contaminants/polycyclic-aromatic-hydrocarbons-pahs#what-happens-when-iam-exposed-to-polycyclic-aromatic-hydrocarbons-(pahs) Polycyclic Aromatic Hydrocarbons (PAHs). (n.d.). Retrieved from http://www.epa.gov/ Shi, J.-H., Lou, Y.-Y., Zhou, K.-L., & Pan, D.-Q. (2018). Exploration of intermolecular interaction of calf thymus DNA with sulfosulfuron using multi-spectroscopic and molecular docking techniques. Spectrochimica Acta Part A: Molecular and Biomolecular Spectros copy, 204, 209–216. doi: 10.1016/j.saa.2018.06.054
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