The gluconeogenesis pathway is involved in maintenance of enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content

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DOIResolve DOI: http://doi.org/10.1371/journal.pone.0098367
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TypeArticle
Journal titlePLoS ONE
ISSN1932-6203
Volume9
Issue6
Article numbere98367
Subjectagmatine; amino acid; asparagine; aspartic acid; complementary DNA; dicarboxylic acid; ethanolamine; glycerol; glycerophosphate; glycine; lactic acid; nitrogen; phosphoenolpyruvate; phosphoenolpyruvate carboxykinase (GTP); pyruvate water dikinase; serine; threonine; transcriptome; tricarboxylic acid; tryptophan; unclassified drug; urea; article; bacterial strain; carbon source; cattle; DNA microarray; enterohemorrhagic Escherichia coli; gastrointestinal tract; gene expression; gluconeogenesis; nonhuman; nucleotide sequence; RNA extraction; small intestine; upregulation; wild type
AbstractEnterohaemorrhagic Escherichia coli (EHEC) are responsible for outbreaks of food- and water-borne illness. The bovine gastrointestinal tract (GIT) is thought to be the principle reservoir of EHEC. Knowledge of the nutrients essential for EHEC growth and survival in the bovine intestine may help in developing strategies to limit their shedding in bovine faeces thus reducing the risk of human illnesses. To identify specific metabolic pathways induced in the animal GIT, the transcriptome profiles of EHEC O157:H7 EDL933 during incubation in bovine small intestine contents (BSIC) and minimal medium supplemented with glucose were compared. The transcriptome analysis revealed that genes responsible for the assimilation of ethanolamine, urea, agmatine and amino acids (Asp, Thr, Gly, Ser and Trp) were strongly up-regulated suggesting that these compounds are the main nitrogen sources for EHEC in BSIC. A central role for the gluconeogenesis pathway and assimilation of gluconeogenic substrates was also pinpointed in EHEC incubated in BSIC. Our results suggested that three amino acids (Asp, Ser and Trp), glycerol, glycerol 3-phosphate, L-lactate and C4-dicarboxylates are important carbon sources for EHEC in BSIC. The ability to use gluconeogenic substrates as nitrogen sources (amino acids) and/or carbon sources (amino acids, glycerol and lactate) may provide a growth advantage to the bacteria in intestinal fluids. Accordingly, aspartate (2.4 mM), serine (1.9 mM), glycerol (5.8 mM) and lactate (3.6 mM) were present in BSIC and may represent the main gluconeogenic substrates potentially used by EHEC. A double mutant of E. coli EDL933 defective for phosphoenolpyruvate synthase (PpsA) and phosphoenolpyruvate carboxykinase (PckA), unable to utilize tricarboxylic acid (TCA) intermediates was constructed. Growth competition experiments between EHEC EDL933 and the isogenic mutant strain in BSIC clearly showed a significant competitive growth advantage of the wild-type strain further illustrating the importance of the gluconeogenesis pathway in maintaining EHEC in the bovine GIT. © 2014 Bertin et al.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Biotechnology Research Institute (BRI-IRB)
Peer reviewedYes
NPARC number21272230
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Record identifiera8896322-8fec-4106-aa9a-e87e4edfb9fa
Record created2014-07-23
Record modified2016-05-09
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