title: Pyruvate oxidase influences the sugar utilization pattern and capsule production in Streptococcus pneumoniae.
abstract: Pyruvate oxidase is a key function in the metabolism and lifestyle of many lactic acid bacteria and its activity depends on the presence of environmental oxygen. In Streptococcus pneumoniae the protein has been suggested to play a major role in metabolism and has been implicated in virulence, oxidative stress survival and death in stationary phase. Under semi-aerobic conditions, transcriptomic and metabolite profiling analysis of a spxB mutant grown on glucose showed minor changes compared to the wild type, apart from the significant induction of two operons involved in carbohydrate uptake and processing. This induction leads to a change in the sugar utilization capabilities of the bacterium, as indicated by the analysis of the growth profiles of the D39 parent and spxB mutant on alternative carbohydrates. Metabolic analysis and growth experiments showed that inactivation of SpxB has no effect on the glucose fermentation pattern, except under aerobic conditions. More importantly, we show that mutation of spxB results in the production of increased amounts of capsule, the major virulence factor of S. pneumoniae. Part of this increase can be attributed to induction of capsule operon (cps) transcription. Therefore, we propose that S. pneumoniae utilizes pyruvate oxidase as an indirect sensor of the oxygenation of the environment, resulting in the adaption of its nutritional capability and the amount of capsule to survive in the host.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Carvalho
authors.forename: Vahid
authors.initials: V
authors.lastname: Farshchi Andisi
authors.forename: Henrik
authors.initials: H
authors.lastname: Gradstedt
authors.forename: Jolanda
authors.initials: J
authors.lastname: Neef
authors.forename: Oscar P
authors.initials: OP
authors.lastname: Kuipers
authors.forename: Ana R
authors.initials: AR
authors.lastname: Neves
authors.forename: Jetta J E
authors.initials: JJ
authors.lastname: Bijlsma
mesh_terms: D016667:Bacterial Capsules / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D050260:Carbohydrate Metabolism; D005285:Fermentation / Q000235:genetics; D017353:Gene Deletion; D020868:Gene Silencing; D005947:Glucose / Q000378:metabolism; D055442:Metabolome; D009154:Mutation; D009876:Operon / Q000235:genetics; D010101:Oxygen Consumption; D010766:Phosphorylation; D011771:Pyruvate Oxidase / Q000235:genetics / Q000378:metabolism*; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D001426:Bacterial Proteins; D011771:Pyruvate Oxidase; D005947:Glucose