Link between Heterotrophic Carbon Fixation and Virulence in the Porcine Lung Pathogen Actinobacillus pleuropneumoniae
| Autor: | Jochen Meens, Elke Goethe, Peter Valentin-Weigand, Esther Surges, Falk F. R. Buettner, Meike Stiesch, Sarah A. Konze, Wolf-Rainer Abraham, Doris Hoeltig, Gerald-F. Gerlach, Charlotte Vogel, Marcel M. M. Kuypers |
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| Rok vydání: | 2019 |
| Předmět: |
Swine
Bicarbonate Immunology Microbiology Carbon Cycle chemistry.chemical_compound Actinobacillus Infections Animals Actinobacillus pleuropneumoniae Pleuropneumonia Virulence biology Carbon fixation Bacterial Infections biology.organism_classification Citric acid cycle Disease Models Animal Metabolic pathway Infectious Diseases Oxaloacetate decarboxylase Biochemistry chemistry Parasitology Phosphoenolpyruvate carboxykinase Phosphoenolpyruvate carboxylase |
| Zdroj: | Infection and Immunity |
| ISSN: | 1098-5522 0019-9567 |
| DOI: | 10.1128/iai.00768-18 |
| Popis: | Actinobacillus pleuropneumoniae is a capnophilic pathogen of the porcine respiratory tract lacking enzymes of the oxidative branch of the tricarboxylic acid (TCA) cycle. We previously claimed that A. pleuropneumoniae instead uses the reductive branch in order to generate energy and metabolites. Here, we show that bicarbonate and oxaloacetate supported anaerobic growth of A. pleuropneumoniae. Isotope mass spectrometry revealed heterotrophic fixation of carbon from stable isotope-labeled bicarbonate by A. pleuropneumoniae, which was confirmed by nano-scale secondary ion mass spectrometry at a single-cell level. By gas chromatography-combustion-isotope ratio mass spectrometry we could further show that the labeled carbon atom is mainly incorporated into the amino acids aspartate and lysine, which are derived from the TCA metabolite oxaloacetate. We therefore suggest that carbon fixation occurs at the interface of glycolysis and the reductive branch of the TCA cycle. The heme precursor delta-aminolevulinic acid supported growth of A. pleuropneumoniae, similar to bicarbonate, implying that anaplerotic carbon fixation is needed for heme synthesis. However, deletion of potential carbon-fixing enzymes, including PEP-carboxylase (PEPC), PEP-carboxykinase (PEPCK), malic enzyme, and oxaloacetate decarboxylase, as well as various combinations thereof, did not affect carbon fixation. Interestingly, generation of a deletion mutant lacking all four enzymes was not possible, suggesting that carbon fixation in A. pleuropneumoniae is an essential metabolic pathway controlled by a redundant set of enzymes. A double deletion mutant lacking PEPC and PEPCK was not impaired in carbon fixation in vitro but showed reduction of virulence in a pig infection model. |
| Databáze: | OpenAIRE |
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