Thesis Defense Announcement
To:  The George Mason University Community

*Candidate: Sarah Hamer
Program: Master of Science in Biology
*Date:   Wednesday August 15, 2012
Time:   2:00 p.m.
Place:  George Mason University, Prince William campus <>
	     Bull Run Hall, Room 247
*Thesis Chair:  Dr. Serguei Popov
Thesis Director: Dr. Myung-Chul Chung

Title: "The S-nitrosylation of Peroxiredoxin 1 during Bacillus anthracis Infection in Human Small Airway Epithelial Cells"

A copy of the thesis is on reserve in the Johnson Center Library, 
Fairfax campus.  The thesis will not be read at the meeting, but should 
be read in advance. All members of the George Mason University community 
are invited to attend.

*Bacillus anthracis, a Gram-positive soil bacterium, is the causative 
agent of anthrax.  B. anthracis is classified as a "Category A" agent by 
the Centers for Disease Control and Prevention.  Although the key 
virulence factors of anthrax are the toxins (i.e. lethal toxin and edema 
toxin), it has been proven that the bacterial nitric oxide synthase 
(bNOS) of B. anthracis also plays a role in pathogenesis.  Since B. 
anthracis infection produces nitric oxide that is responsible for 
S-nitrosylation of host proteins, it was hypothesized that bNOS-induced 
nitric oxide contributes to the regulation of functions in host cells 
through modifications of proteins.  Nitroproteomic analysis using the 
biotin switch technique demonstrated that during B. anthracis infection, 
peroxiredoxin 1 (Prx1) in human small airway epithelial cells (HASECs) 
was predominantly S-nitrosylated.  When Prx1 was S-nitrosylated, there 
was a decrease in its peroxidase activity and an increase in its 
chaperone activity.  Treatment with a nitric oxide donor to ensure that 
proteins were S-nitrosylated showed that in an environment that 
contained hydrogen peroxide, S-nitrosylation contributed to a decrease 
in cell viability.  However, during early B. anthracis infection, 
S-nitrosylation of HSAECs proteins increased cell viability, presumably 
due to Prx1 increased chaperone activity when S-nitrosylated.  It can be 
concluded that during the early stages of B. anthracis infection, nitric 
oxide produced by B. anthracis causes the S-nitrosylation of Prx1, which 
may contribute to an early stage protection (an increase in viability) 
of HSAECs.