AI Article Synopsis
- Francisella tularensis is a highly virulent Gram-negative bacterium that causes tularemia and is classified as a potential bioterrorism agent by the CDC.
- The study explores the role of the peroxiredoxin enzyme AhpC in resisting oxidative stress and its contribution to the virulence of different strains of F. tularensis, specifically the live vaccine strain (LVS) and the highly virulent SchuS4 strain.
- Findings reveal that AhpC acts as a crucial antioxidant in both strains, providing stress resistance and aiding in survival within host cells, indicating differences in antioxidant strategies between LVS and SchuS4.
Article Abstract
Francisella tularensis is a Gram-negative, facultative intracellular pathogen and the causative agent of a lethal human disease known as tularemia. Due to its extremely high virulence and potential to be used as a bioterror agent, F. tularensis is classified by the CDC as a Category A Select Agent. As an intracellular pathogen, F. tularensis during its intracellular residence encounters a number of oxidative and nitrosative stresses. The roles of the primary antioxidant enzymes SodB, SodC and KatG in oxidative stress resistance and virulence of F. tularensis live vaccine strain (LVS) have been characterized in previous studies. However, very fragmentary information is available regarding the role of peroxiredoxin of the AhpC/TSA family (annotated as AhpC) of F. tularensis SchuS4; whereas the role of AhpC of F. tularensis LVS in tularemia pathogenesis is not known. This study was undertaken to exhaustively investigate the role of AhpC in oxidative stress resistance of F. tularensis LVS and SchuS4. We report that AhpC of F. tularensis LVS confers resistance against a wide range of reactive oxygen and nitrogen species, and serves as a virulence factor. In highly virulent F. tularensis SchuS4 strain, AhpC serves as a key antioxidant enzyme and contributes to its robust oxidative and nitrosative stress resistance, and intramacrophage survival. We also demonstrate that there is functional redundancy among primary antioxidant enzymes AhpC, SodC, and KatG of F. tularensis SchuS4. Collectively, this study highlights the differences in antioxidant defense mechanisms of F. tularensis LVS and SchuS4.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6417708 | PMC |
| http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0213699 | PLOS |
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