Application of a GUS reporter system to establish hly transcription in response to oxygen and propionate.
Listeria monocytogenes (LM) is a foodborne pathogen that causes listeriosis through production of the toxin listeriolysin O (LLO). In healthy individuals, the symptoms of listeriosis are minimal; however, severe illness can occur in pregnant women, immunocompromised patients, and the elderly. The Center of Disease Control and Prevention (CDC) has implicated LM to be responsible for 19% of the deaths related to foodborne pathogens. Every year 1,600 people become infected with LM and are hospitalized in the United States and 1in 5 patients do not survive. Due to these statistics, it is important to understand LM virulence and how it is regulated to ensure that the current food safety standards are effective against this pathogen. Previous work has shown that propionate, a common food preservative that also exists within the human gut, increases LLO production anaerobically with the inverse being true aerobically. Thus, if propionate affects LM pathogenesis, we expect the presence of propionate to affect the transcriptional regulation of the gene hly that encodes the protein LLO. This research verifies that a LM strain with a GUS reporter can be used to examine the effect of propionate on the transcriptional regulation of LLO production. Experiments were performed both aerobically and anaerobically in the presence of varying concentrations of propionate (0mM, 5mM, 15mM and 25mM). The results showed that anaerobically as the concentration of propionate increased the intensity of the fluorescence increased, meaning increasing hly transcription. Aerobically, however, the presence of propionate resulted in a decrease in hly transcription. These results highlight the impact propionate on hly transcription and the role of oxygen in LM response to propionate.
Graduate Research - Graduate
Primary Advisor's Department
Stander Symposium project
"Application of a GUS reporter system to establish hly transcription in response to oxygen and propionate." (2017). Stander Symposium Projects. 1002.