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The University of Southern Mississippi

Honors Theses

Anaerobic

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Full-Text Articles in Life Sciences

The Impact Of Oxygen Availability And Oxidative Stress On Regulation Of Cyclic-Dimeric-Gmp In Listeria Monocytogenes Strain F2365, Anna G. Welch May 2021

The Impact Of Oxygen Availability And Oxidative Stress On Regulation Of Cyclic-Dimeric-Gmp In Listeria Monocytogenes Strain F2365, Anna G. Welch

Honors Theses

Listeria monocytogenes is a gram-positive foodborne pathogen that results in the infectious disease listeriosis. The second messenger molecule cyclic-dimeric-GMP has been found to be responsible for the regulation of expression of many of its virulence factors with diguanylate cyclases and phosphodiesterases regulating the intracellular concentration of cyclic-di-GMP through synthesis and degradation, respectively. This study investigated the possibility that the availability of oxygen is the environmental signal crucial to the regulation of these enzymes. Prior research in our laboratory has demonstrated that the intracellular concentration of cyclic-di-GMP is elevated when exposed to anaerobic conditions. Due to this, it was hypothesized that …


Assessing The Effect Of Bile And Oxygen Availability On The Redox Status Of Listeria Monocytogenes Strain F2365, Sukriti Bhattarai May 2020

Assessing The Effect Of Bile And Oxygen Availability On The Redox Status Of Listeria Monocytogenes Strain F2365, Sukriti Bhattarai

Honors Theses

Although bile is a bactericidal agent able to disrupt membrane structure and cellular homeostasis, including the induction of oxidative stress, Listeria can tolerate bile and also utilize it as a signal to enhance infection and virulence. Preliminary findings showed that under anaerobic conditions, exposure to bile significantly lowered the amount of oxidative damage present in bile-resistant strain F2365 cells. Similarly, Listeria further elicits an adaptive immune response, wherein pre-exposure of the bacterium to stress during food processing or in the host prior to entry into the intestine increases bile tolerance. Based on these previous studies, we hypothesized that bile induces …