Aluminum-tolerant Pseudomonas fluorescens: ROS toxicity and enhanced NADPH production.
Aluminum (Al) triggered a marked increase in reactive oxygen species (ROS) such as O(2) (-) and H(2)O(2) in Pseudomonas fluorescens. Although the Al-stressed cells were characterized with higher amounts of oxidized lipids and proteins than controls, NADPH production was markedly increased in these cells. Blue native polyacrylamide gel electrophoresis (BN-PAGE) analyses coupled with activity and Coomassie staining revealed that NADP(+) -dependent isocitrate dehydrogenase (ICDH, E.C. 1.1.1.42) and glucose-6-phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49) played a pivotal role in diminishing the oxidative environment promoted by Al. These enzymes were overexpressed in the Al-tolerant microbes and were modulated by the presence of either Al or hydrogen peroxide (H(2)O(2)) or menadione. The activity of superoxide dismutase (SOD, E.C. 1.15.1.1), an enzyme known to combat ROS stress was also increased in the cells cultured in millimolar amounts of Al. Hence, Al-tolerant P. fluorescens invokes an anti-oxidative defense strategy in order to survive.
Singh
Ranji
R
Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON P3E2C6, Canada.
Beriault
Robin
R
Middaugh
Jeffrey
J
Hamel
Robert
R
Chenier
Daniel
D
Appanna
Vasu D
VD
Kalyuzhnyi
Sergey
S
D000535:Aluminum / Q000494:pharmacology*; D002452:Cell Count; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000633:toxicity*; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D008055:Lipids; D009249:NADP / Q000096:biosynthesis*; D010084:Oxidation-Reduction; D011551:Pseudomonas fluorescens / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000633:toxicity*; D013481:Superoxides / Q000378:metabolism / Q000633:toxicity*
D008055:Lipids; D017382:Reactive Oxygen Species; D013481:Superoxides; D009249:NADP; D006861:Hydrogen Peroxide; D000535:Aluminum; D007521:Isocitrate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase