Affiliation:
1. Unité de Génétique Moléculaire Bactérienne, Institut Pasteur, 75724 Paris Cedex 15, France
Abstract
ABSTRACT
Clostridium perfringens
is a ubiquitous gram-positive pathogen that is present in the air, soil, animals, and humans. Although
C. perfringens
is strictly anaerobic, vegetative and stationary cells can survive in a growth-arrested stage in the presence of oxygen and/or low concentrations of superoxide and hydroxyl radicals. Indeed, it possesses an adaptive response to oxidative stress, which can be activated in both aerobic and anaerobic conditions. To identify the genes involved in this oxidative stress response,
C. perfringens
strain 13 mutants were generated by Tn
916
insertional mutagenesis and screened for resistance or sensitivity to various oxidative stresses. Three of the 12 sensitive mutants examined harbored an independently inserted single copy of the transposon in the same operon as two genes orthologous to the
ydaD
and
ycdF
genes of
Bacillus subtilis
, which encode a putative NADPH dehydrogenase. Complementation experiments and knockout experiments demonstrated that these genes are both required for efficient resistance to oxidative stress in
C. perfringens
and are probably responsible for the production of NADPH, which is required for maintenance of the intracellular redox balance in growth-arrested cells. Other Tn
916
disrupted genes were also shown to play important roles in the oxidative stress response. This is the first time that some of these genes (e.g., a gene encoding an ATP-dependent RNA helicase, the β-glucuronidase gene, and the gene encoding the atypical iron sulfur prismane protein) have been shown to be involved in the oxidative response.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
86 articles.
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