@entity3957 ( @entity3958 ), well known for its toxic properties, has recently become a research focus in bacteria, in part because it has been found to prevent oxidative stress caused by treatment with some antibiotics. @entity3958 has the ability to scavenge reactive @entity26 species (ROS), thus preventing oxidative stress, but it is also toxic, leading to conflicting reports of its effects in different organisms. Here, with @entity18702 as a model, we report that the effects of @entity3958 on the response to oxidative stress are time dependent. When added simultaneously with @entity5568 , @entity3958 promoted @entity5568 @entity137 by inactivating catalase, KatB, a @entity1446 -containing enzyme involved in @entity5568 degradation. Such an inhibitory effect may apply to other @entity1446 -containing proteins, such as cytochrome cbb3 oxidase. When @entity5568 was supplied 20 min or later after the addition of @entity3958 , the oxidative-stress-responding regulator OxyR was activated, resulting in increased resistance to @entity5568 . The activation of OxyR was likely triggered by the influx of @entity68 , a response to lowered intracellular @entity68 due to the @entity68 -sequestering property of @entity3958 . Given that @entity18702 bacteria thrive in redox-stratified environments that have abundant @entity599 and @entity68 species, our results imply that @entity3958 is more important for bacterial survival in such environmental niches than previously believed. IMPORTANCE: Previous studies have demonstrated that @entity3958 is either detrimental or beneficial to bacterial cells. While it can act as a growth-inhibiting molecule by damaging DNA and denaturing proteins, it helps cells to combat oxidative stress. Here we report that @entity3958 indeed has these contrasting biological functions and that its effects are time dependent. Immediately after @entity3958 treatment, there is growth inhibition due to damage of @entity1446 -containing proteins, at least to catalase and cytochrome c oxidase. In contrast, when added a certain time later, @entity3958 confers an enhanced ability to combat oxidative stress by activating the @entity5568 -responding regulator OxyR. Our data reconcile conflicting observations about the functions of @entity3958 .

A Matter of Timing: Contrasting Effects of @entity3957 on Oxidative Stress Response in XXXX .

@entity3958 :: ('CHEBI:36945', 'Chemical') :: ['H2S'] @entity5568 :: ('D006861', 'Chemical') :: ['H2O2'] @entity137 :: ('MESH:D064420', 'Disease') :: ['toxicity'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity599 :: ('MESH:D013455', 'Chemical') :: ['sulfur'] @entity3957 :: ('MESH:D006862', 'Chemical') :: ['Hydrogen sulfide'] @entity18702 :: ('70863', 'Species') :: ['Shewanella oneidensis', 'Shewanella'] @entity68 :: ('MESH:D007501', 'Chemical') :: ['iron'] @entity1446 :: ('MESH:D006418', 'Chemical') :: ['heme']
@entity18702 :: (70863,Species) :: ['Shewanella oneidensis']
