Glycine metabolism and anti-oxidative defence mechanisms in Pseudomonas fluorescens.

Autor: Alhasawi A; Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada., Castonguay Z; Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada., Appanna ND; Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada., Auger C; Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada., Appanna VD; Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada. Electronic address: vappanna@laurentian.ca.
Jazyk: angličtina
Zdroj: Microbiological research [Microbiol Res] 2015 Feb; Vol. 171, pp. 26-31. Date of Electronic Publication: 2015 Jan 06.
DOI: 10.1016/j.micres.2014.12.001
Abstrakt: The role of metabolism in anti-oxidative defence is only now beginning to emerge. Here, we show that the nutritionally-versatile microbe, Pseudomonas fluorescens, reconfigures its metabolism in an effort to generate NADPH, ATP and glyoxylate in order to fend off oxidative stress. Glyoxylate was produced predominantly via the enhanced activities of glycine dehydrogenase-NADP(+) (GDH), glycine transaminase (GTA) and isocitrate lyase (ICL) in a medium exposed to hydrogen peroxide (H₂O₂). This ketoacid was utilized to produce ATP by substrate-level phosphorylation and to neutralize reactive oxygen species with the concomitant formation of formate. The latter was also a source of NADPH, a process mediated by formate dehydrogenase-NADP(+) (FDH). The increased activities of phosphoenolpyruvate carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) worked in tandem to synthesize ATP in the H₂O₂-challenged cells that had markedly diminished capacity for oxidative phosphorylation. These metabolic networks provide an effective means of combating ROS and reveal therapeutic targets against microbes resistant to oxidative stress.
(Copyright © 2014 Elsevier GmbH. All rights reserved.)
Databáze: MEDLINE
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