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.jpg): Failed to open stream: No such file or directory in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 117 J+Biol+Chem
2016 ; 291
(22
): 11928-38
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Role of Glyoxylate Shunt in Oxidative Stress Response
#MMPMID27036942
Ahn S
; Jung J
; Jang IA
; Madsen EL
; Park W
J Biol Chem
2016[May]; 291
(22
): 11928-38
PMID27036942
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The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase,
aceA; and malate synthase, glcB) that serves as an alternative to the
tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of
the tricarboxylic acid cycle and is essential for acetate and fatty acid
metabolism in bacteria. GS can be up-regulated under conditions of oxidative
stress, antibiotic stress, and host infection, which implies that it plays
important but poorly explored roles in stress defense and pathogenesis. In many
bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an
operon, unlike in Escherichia coli In P. aeruginosa, we explored relationships
between GS genes and growth, transcription profiles, and biofilm formation.
Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell
growth under conditions of oxidative and antibiotic stress. Transcriptome data
suggested that aceA mutants underwent a metabolic shift toward aerobic
denitrification; this was supported by additional evidence, including
up-regulation of denitrification-related genes, decreased oxygen consumption
without lowering ATP yield, increased production of denitrification intermediates
(NO and N2O), and increased cyanide resistance. The aceA mutants also produced a
thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic
denitrification. A bioinformatic survey across known bacterial genomes showed
that only microorganisms capable of aerobic metabolism possess the glyoxylate
shunt. This trend is consistent with the hypothesis that the GS plays a
previously unrecognized role in allowing bacteria to tolerate oxidative stress.
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