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Laurisa Ankley

McNair Scholar Laurisa

Laurisa Ankley is an undergraduate biology major at Eastern Washington University in Cheney, Washington.  She assists Dr. Andrea Castillo with her research to find new Helicobacter pylori effectors that contribute to disease.  Laurisa recently presented her project, "Supplemental Iron Offsets the Antibacterial Properties of Manuka Honey", at the National Conference of Undergraduate Research in Memphis, Tennessee.  This project was done under the mentorship of Dr. Robin O'Quinn and Dr. Andrea Castillo.  She will be continuing this project during the summer research internship under the Ronald E. McNair Scholar program.  Moving forward with this project she hopes to determine the mechanism by which supplemental iron blocks the antibacterial properties of Manuka honey.  She is expected to graduate Spring 2018 and plans to continue focusing on research by attending a Master's or Ph.D. program in microbiology. 

McNair Faculty Research Mentor: Dr. Andrea Castillo - Biology

McNair Research Title: How Supplemental Iron Impacts the antibacterial Effect of Manuka Honey

McNair Research Abstract: Pathogenic bacteria have developed resistance to every antibiotic currently available, motivating scientists and medical professionals to find effective alternative treatments.  Honey has captured the attention of researchers, due to its long history of effective medical use as an antibacterial.  Manuka honey in particular, has proven to have strong antibacterial properties.  In addition to hydrogen peroxide, low pH and, high sugar content found in typical honeys, Manuka honey also contains methylglyoxyl from the Leptospermum scoparium flower nectar.  The exact mechanism by which these Manuka honey components, and possibly others, work to kill bacteria and prevent resistance remains unknown.  One hypothesis is that Manuka honey may interfere with iron acquisition.  Bacteria require iron for many processes, including metabolism, gene expression, and enzyme activity; without it, they are unable to survive.  Here, we test this hypothesis by determining if supplemental iron offsets the antibacterial action of Manuka honey.  The minimum inhibitory concentrations for Escherichia coli and Staphylococcus aureus were 6% (n=8) and 3% (n=16) Manuka honey, respectively.  When E. coli cultured with 6% Manuka honey was supplemented with ferrous sulfate (50-500µM), we observed growth that was significantly greater (p= 0.0104) than the E. coli plus 6% Manuka honey alone.  However, supplementation of S. aureus plus 3% Manuka honey with iron (25-500μM) did not restore growth over the no iron control (p=0.2173).  We are further exploring the relationship between Manuka honey's antibacterial action and iron acquisition by repeating these supplementation experiments with E. coli mutants in glyoxylase (gloA) and iron uptake (fur).


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