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Transcriptome response to nitrosative stress in Rhodobacter sphaeroides 2.4.1
Hiroyuki Arai1, Jung Hyeob Roh, Jesus M Eraso
1Department of Microbiology and Molecular Genetics, University of Texas, Houston, USA. aharai@mail.ecc.u-tokyo.ac.jp
Bioscience, Biotechnology, and Biochemistry
|January 8, 2013
Summary
Rhodobacter sphaeroides responds to nitrosative stress via NnrR, regulating nitric oxide reductase (NOR) and other genes. This study reveals NnrR
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Physiology
Background:
- Rhodobacter sphaeroides 2.4.1 possesses a nitric oxide-response regulator (NnrR) and nitric oxide reductase (NOR) but lacks denitrification capabilities.
- Understanding the genomic response to nitrosative stress is crucial for elucidating bacterial adaptive mechanisms.
Purpose of the Study:
- To investigate the physiological and genomic response of R. sphaeroides to nitrosative stress at the transcriptome level.
- To determine the role of the NnrR regulator in the response to reactive nitrogen species.
Main Methods:
- Transcriptome profiling of R. sphaeroides strain 2.4.1 and its NnrR mutant.
- Exposure to nitrosating agents S-nitrosoglutathione (GSNO) and sodium nitroprusside (SNP) under microaerobic conditions.
Main Results:
- GSNO and SNP induced distinct yet overlapping gene expression profiles.
- NnrR controlled a subset of genes, including NOR genes, which were upregulated by both GSNO and SNP.
- Evidence suggests involvement of oxygen-responsive regulator FnrL and an iron-sensing regulator in the response to reactive nitrogen species.
- Dual regulation by NnrR and FnrL was observed for some genes, such as hemN involved in heme biosynthesis.
Conclusions:
- NnrR plays a significant role in the nitrosative stress response of R. sphaeroides, particularly in regulating NOR.
- The bacterium employs complex regulatory networks involving NnrR, FnrL, and potentially iron-sensing mechanisms to cope with reactive nitrogen species.
- Transcriptome analysis provides a genomic basis for understanding R. sphaeroides' adaptation to nitrosative stress.
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