Project description:Background: Pseudomonas aeruginosa, a pathogen infecting those with cystic fibrosis, encounters toxicity from phagocyte-derived reactive oxidants including hydrogen peroxide during active infection. P. aeruginosa responds with adaptive and protective strategies against these toxic species to effectively infect humans. Despite advances in our understanding of the responses to oxidative stress in many specific cases, the connectivity between targeted protective genes and the rest of cell metabolism remains obscure. Results: Herein, we performed a genome-wide transcriptome analysis of the cellular responses to hydrogen peroxide in order to determine a more complete picture of how oxidative stress-induced genes are related and regulated. Our data reinforce the previous conclusion that DNA repair proteins and catalases may be among the most vital antioxidant defense systems of P. aeruginosa. Our results also suggest that sublethal oxidative damage reduces active and/or facilitated transport and that intracellular iron might be a key factor for a relationship between oxidative stress and iron regulation. Perhaps most intriguingly, we revealed that the transcription of all F-, R-, and S-type pyocins was upregulated by oxidative stress and at the same time, a cell immunity protein (pyocin S2 immunity protein) was downregulated, possibly leading to self-killing activity. Conclusions: This finding proposes that pyocin production might be another novel defensive scheme against oxidative attack by host cells. Experiment Overall Design: We conducted four and five independent microarray experiments with biological replicates in the absence (control) and the presence (experimental) of hydrogen peroxide, respectively.
Project description:Background: Pseudomonas aeruginosa, a pathogen infecting those with cystic fibrosis, encounters toxicity from phagocyte-derived reactive oxidants including hydrogen peroxide during active infection. P. aeruginosa responds with adaptive and protective strategies against these toxic species to effectively infect humans. Despite advances in our understanding of the responses to oxidative stress in many specific cases, the connectivity between targeted protective genes and the rest of cell metabolism remains obscure. Results: Herein, we performed a genome-wide transcriptome analysis of the cellular responses to hydrogen peroxide in order to determine a more complete picture of how oxidative stress-induced genes are related and regulated. Our data reinforce the previous conclusion that DNA repair proteins and catalases may be among the most vital antioxidant defense systems of P. aeruginosa. Our results also suggest that sublethal oxidative damage reduces active and/or facilitated transport and that intracellular iron might be a key factor for a relationship between oxidative stress and iron regulation. Perhaps most intriguingly, we revealed that the transcription of all F-, R-, and S-type pyocins was upregulated by oxidative stress and at the same time, a cell immunity protein (pyocin S2 immunity protein) was downregulated, possibly leading to self-killing activity. Conclusions: This finding proposes that pyocin production might be another novel defensive scheme against oxidative attack by host cells. Keywords: Transcriptome study, oxidative stress response
Project description:Reactive oxygen species such as hydrogen peroxide occur in all aerobically living organisms. Oxidative stress during fermentation can impair the fitness of the production host and the quality of the product. B. pumilus has been described as highly resistant to hydrogen peroxide. The response of exponentially growing B. pumilus cells to hydrogen peroxide was studied.
Project description:Adaptation to hydrogen peroxide in Saccharomyces cerevisiae is profiled with expression arrays. Adaptation describes the process in which a mild dose of toxin (in this case, hydrogen peroxide) is able to protect against a later acute dose. Here, we study two adaptive protocols (0.1 mM H2O2 and 0.1 + 0.4 mM H2O2) and one acute protocol (0.4 mM H2O2) to identify processes uniquely involved in adaptation. Predictions from these studies are validated in expression profiling of deletion mutants of the transcription factors Yap1, Mga2, and Rox1.
Project description:Reactive oxygen species such as hydrogen peroxide occur in all aerobically living organisms. Oxidative stress during fermentation can impair the fitness of the production host and the quality of the product. B. pumilus has been described as highly resistant to hydrogen peroxide. The response of exponentially growing B. pumilus cells to hydrogen peroxide was studied. Two-condition experiment, unstressed versus hydrogen peroxide stressed cells, 3 biological replicates
Project description:To gain insight into the basic mechanism of Hydrogen peroxide detoxification in the methylotrophic yeast, H. polymorpha, we analyzed changes in transcriptional profiles in response to hydrogen peroxide exposure.
Project description:Using data from microarray experiments, we investigated the effects of excess hydrogen peroxide on D. vulgaris. Keywords: stress response, time course