Oxidation of hemoproteins by collapses the cell cytoskeleton and disrupts mitochondrial respiration leading to the cytotoxicity of human lung cells.

(Spn) colonizes the lungs, killing millions every year. During its metabolism, Spn produces abundant amounts of hydrogen peroxide. When produced in the lung parenchyma, Spn-hydrogen peroxide (HO) causes the death of lung cells, and details of the mechanism are studied here.

Oxidation of hemoglobin in the lung parenchyma facilitates the differentiation of pneumococci into encapsulated bacteria.

Unlabelled: Pneumococcal pneumonia causes cytotoxicity in the lung parenchyma but the underlying mechanism involves multiple factors contributing to cell death. Here, we discovered that hydrogen peroxide produced by (Spn-H O ) plays a pivotal role by oxidizing hemoglobin, leading to its polymerization and subsequent release of labile heme. At physiologically relevant levels, heme selected a population of encapsulated pneumococci.

Oxidation of hemoproteins by collapses the cell cytoskeleton and disrupts mitochondrial respiration leading to cytotoxicity of human lung cells.

(Spn) causes pneumonia that kills millions through acute toxicity and invasion of the lung parenchyma. During aerobic respiration, Spn releases hydrogen peroxide (Spn-H O ), as a by-product of enzymes SpxB and LctO, and causes cell death with signs of both apoptosis and pyroptosis by oxidizing unknown cell targets. Hemoproteins are molecules essential for life and prone to oxidation by H O .

Oxidative Reactions Catalyzed by Hydrogen Peroxide Produced by Streptococcus pneumoniae and Other Streptococci Cause the Release and Degradation of Heme from Hemoglobin.

Streptococcus pneumoniae (Spn) strains cause pneumonia that kills millions every year worldwide. Spn produces Ply, a hemolysin that lyses erythrocytes releasing hemoglobin, and also produces the pro-oxidant hydrogen peroxide (Spn-HO) during growth. The hallmark of the pathophysiology of hemolytic diseases is the oxidation of hemoglobin, but oxidative reactions catalyzed by Spn-HO have been poorly studied.

Synergistic Protection against Secondary Pneumococcal Infection by Human Monoclonal Antibodies Targeting Distinct Epitopes.

persists as a leading cause of bacterial pneumonia despite the widespread use of polysaccharide-based vaccines. The limited serotype coverage of current vaccines has led to increased incidence of nonvaccine serotypes, as well as an increase in antibiotic resistance among these serotypes. Pneumococcal infection often follows a primary viral infection such as influenza virus, which hinders host defense and results in bacterial spread to the lungs.

Prophylactic Inhibition of Colonization by Streptococcus pneumoniae with the Secondary Bile Acid Metabolite Deoxycholic Acid.

Streptococcus pneumoniae colonizes the nasopharynx of children and the elderly but also kills millions worldwide yearly. The secondary bile acid metabolite deoxycholic acid (DoC) affects the viability of human pathogens but also plays multiple roles in host physiology. We assessed the antimicrobial activity of DoC and investigated its potential to eradicate S.

Hydrogen Peroxide Production by Streptococcus pneumoniae Results in Alpha-hemolysis by Oxidation of Oxy-hemoglobin to Met-hemoglobin.

and other streptococci produce a greenish halo on blood agar plates referred to as alpha-hemolysis. This phenotype is utilized by clinical microbiology laboratories to report culture findings of alpha-hemolytic streptococci, including , and other bacteria. The alpha-hemolysis halo on blood agar plates has been related to the hemolytic activity of pneumococcal pneumolysin (Ply) or, to a lesser extent, to lysis of erythrocytes by -produced hydrogen peroxide.