Protection from hydrogen peroxide stress relies mainly on AhpCF and KatA2 in Stenotrophomonas maltophilia

Journal of Biomedical Science

卷:27

Chao-Jung Wu¹  Tsuey-Ching Yang¹  Yu-Chieh Tsai¹  Yi-Wei Huang¹  Hsin-Hui Huang¹  Jing-Yun Huang²  Yung-Luen Shih³  Li-Hua Li⁴ 

[1] Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University;

[2] Department of Laboratory Medicine, Chang-Gung Memorial Hospital;

[3] Department of Pathology and Laboratory Medicine, Shin Kong Wu Ho-Su Memorial Hospital;

[4] Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital;

关键词: Stenotrophomonas maltophilia;    Catalase;    Alkyl hydroperoxidase;    Glutathione peroxidase;    Hydrogen peroxide stress;    OxyR regulator;   

DOI  :  10.1186/s12929-020-00631-4

来源: DOAJ

【 摘 要 】

Abstract Background Aerobically-grown bacteria can be challenged by hydrogen peroxide stress from endogenous aerobic metabolism and exogenously generated reactive oxygen species. Catalase (Kat), alkyl hydroperoxidase (Ahp), and glutathione peroxidase (Gpx) systems are major adaptive responses to H2O2 stress in bacteria. Stenotrophomonas maltophilia is a ubiquitous Gram-negative bacterium equipped with four Kats (KatA1, KatA2, KatMn, and KatE), one Ahp (AhpCF), and three Gpxs (Gpx1, Gpx2, and Gpx3). Here, we systematically investigated how the eight H2O2 scavenging genes differentially contribute to the low-micromolar levels of H2O2 generated from aerobic metabolism and high-millimolar levels of H2O2 from exogenous sources. Methods Gene expression was assessed and quantified by reverse transcription-PCR (RT-PCR) and real time quantitative PCR (qRT-PCR), respectively. The contribution of these enzymes to H2O2 stress was assessed using mutant construction and functional investigation. Results Of the eight genes, katA2, ahpCF, and gpx3 were intrinsically expressed in response to low-micromolar levels of H2O2 from aerobic metabolism, and the expression of katA2 and ahpCF was regulated by OxyR. AhpCF and KatA2 were responsible for alleviating aerobic growth-mediated low concentration H2O2 stress and AhpCF played a critical role for stationary-phase cells. KatA2 was upregulated to compensate for AhpCF in the case of ahpCF inactivation. After exposure to millimolar levels of H2O2, katA2 and ahpCF were upregulated in an OxyR-dependent manner. KatA2 was the critical enzyme for dealing with high concentration H2O2. Loss-of-function of KatA2 increased bacterial susceptibility to high concentration H2O2. Conclusions AhpCF and KatA2 are key enzymes protecting S. maltophilia from hydrogen peroxide stress.

【 授权许可】

Unknown