Disease relevance of spxB

• We propose that a mutation in spxB leads to down-regulation of the multiple adhesive properties of pneumococcus which, in turn, may correlate to diminished virulence in vivo [1].
• Compared to the parent strain, an spxB mutant showed reduced virulence in animal models for nasopharyngeal colonization, pneumonia, and sepsis [1].

High impact information on spxB

• A defect in spxB corresponded to impaired virulence of the mutant in vivo [1].
• Analysis of the locus altered in this mutant revealed a gene, spxB, that encodes a member of the family of bacterial pyruvate oxidases which decarboxylates pyruvate to acetyl phosphate plus H2O2 and CO2 [1].
• Hydrogen peroxide is produced by the pneumococcus through the action of pyruvate oxidase (SpxB) under conditions of aerobic growth [2].
• R36A requires a wild-type spxB allele for the expression of smooth type 2 morphology but not for the expression of smooth type 3 morphology, the phenotype monitored by Avery et al [3].
• Increased pyruvate oxidase activity alters colony shape by mediating cell death [3].

Chemical compound and disease context of spxB

• Factors contributing to hydrogen peroxide resistance in Streptococcus pneumoniae include pyruvate oxidase (SpxB) and avoidance of the toxic effects of the fenton reaction [4].

Anatomical context of spxB

• Both nanA and spxB mRNAs were present in higher amounts in the nasopharynx than in the lungs or blood [5].

Associations of spxB with chemical compounds

• During H(2)O(2) exposure, ATP levels decreased more rapidly in spxB mutants than in wild-type cells, suggesting that the increased killing of spxB mutants was due to more rapid ATP depletion [4].
• Neither lactate dehydrogenase nor pyruvate oxidase, dominant intracellular proteins, were present among the proteins on the gels, demonstrating that proteins in the surface-associated pool did not arise as a result of cell lysis [6].

References