LanguageTerm (authority = ISO 639-3:2007); (type = text)
English
Abstract (type = abstract)
Staphylococcus aureus is a public health concern. It can evade the immune system and develop resistance to many antibiotic classes. The human immune system employs diverse mechanisms to overcome S. aureus infections including disrupting iron (Fe) and copper (Cu) homeostasis at the host-pathogen interface. The work presented herein described iron-sulfur (Fe-S) cluster synthesis as a potential antimicrobial target. We demonstrated that Suf (sulfur mobilization)-dependent Fe-S cluster synthesis is essential in S. aureus. Importantly, the Suf system is not present in mammals suggesting that it is a promising antibiotic target. A strain with decreased suf transcription exhibited phenotypes that are associated with impaired Fe-S protein maturation. These phenotypes included a reduction in the activity of Fe-S cluster-dependent enzymes and growth inhibition in media deficient in metabolites that require Fe-S enzymes for synthesis. The impairment in Fe-S cluster biogenesis led to increased sensitivity to reactive oxygen and reactive nitrogen species and decreased survival in human polymorphonuclear leukocytes. We explored how copper harm S. aureus, by creating a ΔcopAB ΔcopBL strain (cop-) that was defective in removing copper from the cytosol. We isolated cop- strains with Tn insertions in mntABC that resist copper. When cultured with copper, strains containing the mntA::Tn mutation had less copper load than the parent strains. Manganese bound MntR repressed MntABC. The ?mntR strain had reduced growth and increased copper load under copper stress. The introduction of the mntA::Tn allele annulled these phenotypes. Over-expression of MntABC amplified cellular copper load and sensitivity to copper. The mntA::Tn mutation presence also protected Fe-S enzymes from inactivation by copper. We also found that copper was not substantially inhibiting the growth of S. aureus by poisoning NrdEF under the growth conditions utilized; however, when NrdEF function was decreased by copper, the ribonucleotide reductase function is decreased by the addition of hydroxyurea. The introduction of a mntA::Tn allele improved growth of both ΔcopAZ and ΔcopBL strains from copper intoxication suggesting that the presence of a second copper detoxification system protects S. aureus from MntABC-dependent copper intoxication. The data presented are consistent with a model wherein copper enters S. aureus cells via the MntABC importer and poisons Fe-S enzymes. Taken together, the work presented in this thesis supports the viability of targeting Fe-S synthesis as a viable therapeutic approach and established a novel role for mntABC in copper homeostasis.
Subject (authority = RUETD)
Topic
Microbial Biology
Subject (authority = local)
Topic
Metals homeostasis
Subject (authority = LCSH)
Topic
Staphylococcus aureus
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_10093
PhysicalDescription
Form (authority = gmd)
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (xi, 143 pages) : illustrations
Note (type = degree)
Ph.D.
Note (type = bibliography)
Includes bibliographical references
RelatedItem (type = host)
TitleInfo
Title
School of Graduate Studies Electronic Theses and Dissertations
Identifier (type = local)
rucore10001600001
Location
PhysicalLocation (authority = marcorg); (displayLabel = Rutgers, The State University of New Jersey)
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.