PspA-mediated aggregation protects against desiccation on fomites.

is a dangerous human pathogen capable of causing pneumonia and invasive disease. The virulence factor PspA has been studied for nearly four decades with well-established roles in pneumococcal evasion of C-reactive protein and neutralization of lactoferricin. Herein, we show that mammalian (m)GAPDH in mucosal secretions promotes aggregation of pneumococci in a PspA-dependent fashion, whereas lactoferrin counters this effect.

PspA-mediated aggregation protects against desiccation on fomites.

() resides in the nasopharynx where it can disseminate to cause disease. One key virulence factor is pneumococcal surface protein A (PspA), which promotes survival by blocking the antimicrobial peptide lactoferricin. PspA has also been shown to mediate attachment to dying epithelial cells in the lower airway due to its binding of cell surface-bound mammalian (m)GAPDH.

A Jack of All Trades: The Role of Pneumococcal Surface Protein A in the Pathogenesis of .

(), or the pneumococcus, is a Gram-positive bacterium that colonizes the upper airway. is an opportunistic pathogen capable of life-threatening disease should it become established in the lungs, gain access to the bloodstream, or disseminate to vital organs including the central nervous system. is encapsulated, allowing it to avoid phagocytosis, and current preventative measures against infection include polyvalent vaccines composed of capsular polysaccharide corresponding to its most prevalent serotypes.

High-throughput suppressor screen demonstrates that RcsF monitors outer membrane integrity and not Bam complex function.

The regulator of capsule synthesis (Rcs) is a complex signaling cascade that monitors gram-negative cell envelope integrity. The outer membrane (OM) lipoprotein RcsF is the sensory component, but how RcsF functions remains elusive. RcsF interacts with the β-barrel assembly machinery (Bam) complex, which assembles RcsF in complex with OM proteins (OMPs), resulting in RcsF's partial cell surface exposure.

Improper Coordination of BamA and BamD Results in Bam Complex Jamming by a Lipoprotein Substrate.

The β-barrel assembly machinery, the Bam complex, is central to the biogenesis of integral outer membrane proteins (OMPs) as well as OMP-dependent surface-exposed lipoproteins, such as regulator of capsule synthesis protein F (RcsF). Previous genetic analysis established the model that nonessential components BamE and BamB have overlapping, redundant functions to enhance the kinetics of the highly conserved BamA/BamD core. Here we report that BamE plays a specialized nonredundant role in the Bam complex required for surface exposure of RcsF.

Negative Control of RpoS Synthesis by the sRNA ReaL in .

(Pae) is an opportunistic human pathogen, able to resist host defense mechanisms and antibiotic treatment. In Pae, the master regulator of stress responses RpoS (σ) is involved in the regulation of quorum sensing and several virulence genes. Here, we report that the sRNA ReaL translationally silences mRNA, which results in a decrease of the RpoS levels.

The Anaerobically Induced sRNA PaiI Affects Denitrification in PA14.

is an opportunistic pathogen that can thrive by anaerobic respiration in the lungs of cystic fibrosis patients using nitrate as terminal electron acceptor. Here, we report the identification and characterization of the small RNA PaiI in the strain 14 (PA14). PaiI is naerobically nduced in the presence of nitrate and depends on the two-component system NarXL.

Cross-regulation by CrcZ RNA controls anoxic biofilm formation in Pseudomonas aeruginosa.

Pseudomonas aeruginosa (PA) can thrive in anaerobic biofilms in the lungs of cystic fibrosis (CF) patients. Here, we show that CrcZ is the most abundant PA14 RNA bound to the global regulator Hfq in anoxic biofilms grown in cystic fibrosis sputum medium. Hfq was crucial for anoxic biofilm formation.

RNASeq Based Transcriptional Profiling of Pseudomonas aeruginosa PA14 after Short- and Long-Term Anoxic Cultivation in Synthetic Cystic Fibrosis Sputum Medium.

The opportunistic human pathogen Pseudomonas aeruginosa can thrive under microaerophilic to anaerobic conditions in the lungs of cystic fibrosis patients. RNASeq based comparative RNA profiling of the clinical isolate PA14 cultured in synthetic cystic fibrosis medium was performed after planktonic growth (OD600 = 2.0; P), 30 min after shift to anaerobiosis (A-30) and after anaerobic biofilm growth for 96h (B-96) with the aim to reveal differentially regulated functions impacting on sustained anoxic biofilm formation as well as on tolerance towards different antibiotics.