Blythe Janowiak
B.A. Chemistry
B.A. Biology
DePauw University
Project: Characterization of glutathione synthesis in
Streptococcus agalactiae and Streptococcus pyogenes and the role of glutathione in bacterial survival
Advisor: Dr Owen Griffith
Streptococcus agalactiae and Streptococcus pyogenes are important human pathogens,
causing a range of diseases including neonatal meningitis, streptococcal pharyngitis (strep throat),
scarlet fever, rheumatic fever, and post streptococcal glomerulonephritis. As many antibiotic-resistant
strains of these streptococcal species have developed, it becomes necessary to find new approaches
to control streptococcal infections. Since the generation of free radical species by professional phagocytes
is the initial host response to a strep infection, streptococcal oxidative stress defenses represent an
attractive and novel antimicrobial target. Glutathione (GSH, gamma-glutamylcysteinylglycine) is the
main anti-oxidant thiol in these species. Since streptococci lack catalase, the main peroxidase in
most bacteria, these bacteria are likely to rely heavily on their GSH system to combat oxidative stress.
To date, GSH biosynthesis has not been characterized in any Gram-positive bacteria, and thus my
project is to characterize GSH biosynthesis in both S. agalactiae and S. pyogenes and also to
elucidate the role of GSH in these bacteria during a strep infection. The therapeutic potential of
streptococcal-specific GSH synthesis will be explored.
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