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Comparative analysis of the responses of related pathogenic and environmental bacteria to oxidative stress

Lookup NU author(s): Dr Susanne Pohl, Pijug Summpunn, Sandra Kerstan, Professor Colin Harwood


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Bacillus anthracis, the causative agent of anthrax, is exposed to host-mediated antibacterial activities, such as reactive oxygen species (ROS), during the early stages of its disease process. The ability to resist these host-mediated insults is an essential characteristic of a successful pathogen while it is generally assumed that non-pathogenic environmental bacteria succumb to these antimicrobial activities. In order to gain insights into the underlying mechanisms that pathogens use to resist host-mediated oxidative stress, we have compared the oxidative stress responses of B. anthracis and B. subtilis, a well-studied environmental bacterium. Among the four putative catalases encoded by B. anthracis we identified KatB as the main vegetative catalase. Comparative analysis of catalase production in B. anthracis and B. subtilis in response to superoxide and peroxide stress reveals different expression profiles, even though both are regulated by the PerR repressor that senses and responds to peroxide stress. A B. anthracis perR deletion mutant exhibits enhanced KatB activity and is hyper-resistant to peroxide stress. Superoxide dismutase A1 (SodA1) is the main contributor to the intracellular superoxide dismutase activity in vegetative cells and the gene encoding this enzyme is constitutively expressed. Although aspects of the ROS detoxifying systems of B. anthracis and B. subtilis are similar, their responses to superoxide stress are different. The observed differences are likely to reflect adaptations specific environmental niches.

Publication metadata

Author(s): Tu WY, Pohl S, Summpunn P, Hering S, Kerstan S, Harwood CR

Publication type: Article

Publication status: Published

Journal: Microbiology

Year: 2012

Volume: 158

Pages: 636-647

ISSN (print): 1350-0872

ISSN (electronic): 1465-2080

Publisher: Society for General Microbiology


DOI: 10.1099/mic.0.057000-0


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Funder referenceFunder name
Sarawak Foundation, Malaysia
Overseas Research Student Award Scheme (ORSAS) from UK higher education funding bodies