Staphylococcus aureus Indicator

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Authors
Crichton, Juliette
Breit, Julianna
Chennai, Oviya
Lieberg, Jaedon
Kuga, Kylie
Advisor
Rowley, John
Editor
Date of Issue
2023-04-28
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Citation
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Title
Staphylococcus aureus Indicator
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Type
Presentation
Description
Abstract
The long-range objective of this research is to develop a chemical method to detect Staphylococcus aureus (S. aureus). Herein we assess the viability of using the controlled emission and quenching of fluorescent dyes as that chemical detection method. One of the major extracellular proteases produced by S. aureus is the V8 protease which cleaves peptide bonds connected to glutamic acid. When the V8 protease cleaves the dye-quenching glutamic acid from the dye-tagged amino acid chain, the remaining poorly-quenching amino acid will allow the dye to fluoresce, indicating the presence of S. aureus. Preliminary fluorescence quenching of 2’7 dichlorofluorescein (2’7 DCF) was performed using Stern-Volmer analysis to assess the viability of a fluorophore-quencher/peptide compound. Irrespective of pH, the fluorescence of 2’7 DCF was strongly quenched by glutamic acid with a quenching constant of 37.04. The fluorescence of 2’7 DCF was weakly quenched by amino acids alanine, proline, and glycine with quenching constants of 1.24, 1.28, and 1.27 respectively. Using this quenching behavior, we propose the synthesis of a fluorophore-quencher/peptide compound in which the 2’7 DCF is covalently bound to a weakly quenching peptide chain containing glutamic acid.
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Degree Awarded
Semester
Spring
Department
Biochemistry-Molecular Biology