Bacteria communicate with each other to coordinate expression of specific genes in a cell density-dependent fashion, phenomenon called quorum sensing and response. Although we know that via acyl-homoserine lactone (HSL) signals controls several virulence the human pathogen Pseudomonas aeruginosa , number types controlled by have not been studied systematically. We constructed library random insertions chromosome P. acyl-HSL synthesis mutant using transposon containing promoterless lacZ ....

ABSTRACT The sputum (mucus) layer of the cystic fibrosis (CF) lung is a complex substrate that provides Pseudomonas aeruginosa with carbon and energy to support high-density growth during chronic colonization. Unfortunately, CF has been difficult mimic in animal models disease, mechanistic studies P. physiology are hampered by its complexity. In this study, we performed chromatographic enzymatic analyses develop defined, s ynthetic m edium (SCFM) mimics nutritional composition sputum....

The opportunistic pathogenic bacterium Pseudomonas aeruginosa uses quorum-sensing signaling systems as global regulators of virulence genes. There are two signal receptor and generator pairs, LasR–LasI RhlR–RhlI. recently completed P. genome-sequencing project revealed a gene coding for homolog the receptors, LasR RhlR. Here we describe role this gene, which call qscR . product governs timing quorum-sensing-controlled expression it dampens in an insect model. We present evidence that...

Significance The opportunistic pathogen Pseudomonas aeruginosa thrives in cystic fibrosis (CF) lung sputum. Here, we define the essential genome of two P. strains laboratory media and CF We also use genomic methods to profile genetic requirements for fitness both natural synthetic Finally, show that genomes different are distinct, suggesting architecture networks is a primary determinant gene’s role fitness. This has implications development strain-independent therapeutics underscores...

ABSTRACT The human microbiome plays important roles in health, but when disrupted, these same indigenous microbes can cause disease. composition of the changes during transition from health to disease; however, are often not conserved among patients. Since microbiome-associated diseases like periodontitis similar patient symptoms despite interpatient variability microbial community composition, we hypothesized that human-associated communities undergo metabolism Here, used patient-matched...

Opportunistic infections caused by Pseudomonas aeruginosa can be acute or chronic. While often spread rapidly and cause tissue damage sepsis with high mortality rates, chronic persist for weeks, months, years in the face of intensive clinical intervention. Remarkably, this diverse infectious capability is not accompanied extensive variation genomic content, suggesting that genetic capacity to an a pathogen present most P. strains. To investigate requirements pathogenesis infections, we...

Most infections result from colonization by more than one microbe. Within such polymicrobial infections, microbes often display synergistic interactions that in increased disease severity. Although many clinical studies have documented the occurrence of synergy little is known about underlying molecular mechanisms. A prominent pathogen Pseudomonas aeruginosa , a Gram-negative bacterium displays enhanced virulence during coculture with Gram-positive bacteria. In this study we discovered...

Microbes within polymicrobial infections often display synergistic interactions resulting in enhanced pathogenesis; however, the molecular mechanisms governing these are not well understood. Development of model systems that allow detailed mechanistic studies synergy is a critical step towards comprehensive understanding vivo. In this study, we used infection including opportunistic pathogen Aggregatibacter actinomycetemcomitans and commensal Streptococcus gordonii to examine importance...

Despite its highly inflammatory nature, LPS is a molecule with remarkable therapeutic potential. Lipid A glycolipid that serves as the hydrophobic anchor of and constitutes potent ligand Toll-like receptor (TLR)4/myeloid differentiation factor 2 innate immune system. less toxic mixture monophosphorylated lipid species (MPL) recently became first new Food Drug Administration-approved adjuvant in over 70 y. Whereas wild-type Escherichia coli provokes strong MyD88 (myeloid primary response gene...

Background A basic paradigm of human infection is that acute bacterial disease caused by fast growing planktonic bacteria while chronic infections are slow-growing, aggregated bacteria, a phenomenon known as biofilm. For lung infections, this has been thought to be supported observations how proliferate in well-established growth media the laboratory—the gold standard microbiology. Objective To investigate architecture sputum from patients with and infections. Methods Advanced imaging...

Abstract The ability to switch between different lifestyles allows bacterial pathogens thrive in diverse ecological niches 1,2 . However, a molecular understanding of their lifestyle changes within the human host is lacking. Here, by directly examining gene expression human-derived samples, we discover that orchestrates transition chronic and acute infection opportunistic pathogen Pseudomonas aeruginosa level this gene, here named sicX , highest P. genes expressed wound cystic fibrosis...

ABSTRACT Transcriptional profiles of Pseudomonas aeruginosa exposed to two separate copper stress conditions were determined. Actively growing bacteria subjected a pulse elevated for short period time was defined as “copper-shocked” culture. Conversely, copper-adapted populations cells actively in the presence copper. Expression 405 genes changed copper-shocked culture, compared 331 cultures. Not surprisingly, there identified common both conditions. For example, resulted up-regulation...

ABSTRACT The LasR-LasI and RhlR-RhlI quorum-sensing systems are global regulators of gene expression in the opportunistic pathogen Pseudomonas aeruginosa . Previous studies suggest that system activates rpoS We constructed merodiploid strains P. containing native an rpoS-lacZ fusion. Studies lacZ transcription these indicated was not regulated by RhlR-RhlI. also generated null mutant. This mutant showed elevated levels rhlI (but rhlR ) transcription, RhlI-generated acylhomoserine lactone...

ABSTRACT Gram-negative bacteria naturally produce outer membrane vesicles (OMVs) that arise through bulging and pinching off of the membrane. OMVs have several biological functions for bacteria, most notably as trafficking vehicles toxins, antimicrobials, signaling molecules. While their roles are now appreciated, mechanism OMV formation has not been fully elucidated. We recently demonstrated molecule 2-heptyl-3-hydroxy-4-quinolone (PQS) is required biogenesis in P. aeruginosa . hypothesized...

Significance Polymicrobial synergy occurs when infections caused by more than one species are severe the sum of individual acting alone. Here, we show that a bacterial fight-and-flight response to an antimicrobial, hydrogen peroxide (H 2 O ), is required for pathogen display with commensal bacterium in vivo. H generated commensal, and response, either enzymatically destroys (fights) antimicrobial or disperses away (takes flight) from antimicrobial-producing commensal. Remarkably, both...

The relevance of the acyl homoserine lactone (acyl-HSL) quorum signals N-3-oxododecanoyl-homoserine (3OC12HSL) and N-butanoyl-homoserine to biology virulence Pseudomonas aeruginosa is well investigated. Previously, P. was shown degrade long-chain, but not short-chain, acyl-HSLs as sole carbon energy sources (J. J. Huang, J.-I. Han, L.-H. Zhang, R. Leadbetter, Appl. Environ. Microbiol. 69:5941-5949, 2003). A gene encoding an enzyme with acyl-HSL acylase activity, pvdQ (PA2385), identified, it...

Abstract Proteins play major roles in most biological processes; as a consequence, protein expression levels are highly regulated. While extensive post‐transcriptional, translational and degradation control clearly influence concentration functionality, it is often thought that abundances primarily determined by the of corresponding mRNAs. Hence surprisingly, recent study showed orthologous nematode fly proteins correlate better than their mRNA abundances. We tested if this phenomenon...

ABSTRACT The autosomal recessive disorder cystic fibrosis (CF) affects approximately 70,000 people worldwide and is characterized by chronic bacterial lung infections with the opportunistic pathogen Pseudomonas aeruginosa . To form a CF infection, P. must grow proliferate within lung, highly viscous sputum provides likely growth substrate. Recent evidence indicates that anaerobic microenvironments may be present in layer. Since significantly enhances biofilm formation antibiotic resistance,...

Significance Quorum sensing is a communication system that allows bacteria to coordinate their activities, and these systems are critical for virulence in several bacteria, including Pseudomonas aeruginosa . There significant gap knowledge about how quorum proceeds during infection, particularly spatial organization of the infecting microbial community impacts signaling. Using model recapitulates biogeographical properties P. infection cystic fibrosis lung, we discovered primarily occurs...

Abstract MicroRNAs (miRNAs) play essential roles in plant and animal development, but the cause effect of miRNA expression divergence between closely related species interspecific hybrids or allopolyploids are unknown. Here, we show differential regulation a miR163-mediated pathway allotetraploids their progenitors, Arabidopsis thaliana arenosa. miR163 is recently evolved A. highly expressed thaliana, its was undetectable arenosa repressed resynthesized allotetraploids. Repression MIR163 (Aa...

Alginate beads represent a simple and highly reproducible in vitro model system for diffusion-limited bacterial growth. In this study, alginate were inoculated with Pseudomonas aeruginosa followed up to 72 h. Confocal microscopy revealed that P. formed dense clusters similar size vivo aggregates observed ex cystic fibrosis lungs chronic wounds. Bacterial primarily grew the bead periphery decreased abundance toward center of bead. Microsensor measurements showed O2 concentration rapidly...