Metabolic versatility in Haemophilus influenzae: a metabolomic and genomic analysis

Othman, Dk Seti Maimonah Pg, Schirra, Horst, McEwan, Alastair G. and Kappler, Ulrike (2014) Metabolic versatility in Haemophilus influenzae: a metabolomic and genomic analysis. Frontiers in Microbiology, 5 MAR: 69.1-69.10. doi:10.3389/fmicb.2014.00069

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Author Othman, Dk Seti Maimonah Pg
Schirra, Horst
McEwan, Alastair G.
Kappler, Ulrike
Title Metabolic versatility in Haemophilus influenzae: a metabolomic and genomic analysis
Formatted title
Metabolic versatility in Haemophilus influenzae: a metabolomic and genomic analysis
Journal name Frontiers in Microbiology   Check publisher's open access policy
ISSN 1664-302X
Publication date 2014-03-04
Sub-type Article (original research)
DOI 10.3389/fmicb.2014.00069
Open Access Status DOI
Volume 5
Issue MAR
Start page 69.1
End page 69.10
Total pages 10
Place of publication Lausanne, Switzerland
Publisher Frontiers Research Foundation
Collection year 2015
Language eng
Formatted abstract
Haemophilus influenzae is a host adapted human pathogen known to contribute to a variety of acute and chronic diseases of the upper and lower respiratory tract as well as the middle ear. At the sites of infection as well as during growth as a commensal the environmental conditions encountered by H. influenzae will vary significantly, especially in terms of oxygen availability, however, the mechanisms by which the bacteria can adapt their metabolism to cope with such changes have not been studied in detail. Using targeted metabolomics the spectrum of metabolites produced during growth of H. influenzae on glucose in RPMI-based medium was found to change from acetate as the main product during aerobic growth to formate as the major product during anaerobic growth. This change in end-product is likely caused by a switch in the major route of pyruvate degradation. Neither lactate nor succinate or fumarate were major products of H. influenzae growth under any condition studied. Gene expression studies and enzyme activity data revealed that despite an identical genetic makeup and very similar metabolite production profiles, H. influenzae strain Rd appeared to favor glucose degradation via the pentose phosphate pathway, while strain 2019, a clinical isolate, showed higher expression of enzymes involved in glycolysis. Components of the respiratory chain were most highly expressed during microaerophilic and anaerobic growth in both strains, but again clear differences existed in the expression of genes associated e.g., with NADH oxidation, nitrate and nitrite reduction in the two strains studied. Together our results indicate that H. influenzae uses a specialized type of metabolism that could be termed “respiration assisted fermentation” where the respiratory chain likely serves to alleviate redox imbalances caused by incomplete glucose oxidation, and at the same time provides a means of converting a variety of compounds including nitrite and nitrate that arise as part of the host defence mechanisms. 
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Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Chemistry and Molecular Biosciences
Centre for Advanced Imaging Publications
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
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Created: Fri, 21 Mar 2014, 10:56:29 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences