Summary The role of quorum sensing in Pseudomonas aeruginosa biofilm formation is unclear. Some researchers have shown that important for development, while others indicated it has little or no role. In this study, the contribution to development was found depend upon nutritional environment. Depending carbon source, quorum‐sensing mutant strains ( lasIrhlI and lasRrhlR ) either exhibited a pronounced defect early formed biofilms identical wild‐type strain. Quorum then exert its...

Bacterial biofilms are structured multicellular communities involved in a broad range of infections. Knowing how free-swimming bacteria adapt their motility mechanisms near surfaces is crucial for understanding the transition between planktonic and biofilm phenotypes. By translating microscopy movies into searchable databases bacterial behavior, we identified fundamental type IV pili-driven Pseudomonas aeruginosa surface distinct foraging strategies. Bacteria stood upright "walked" with...

Mass spectrometry imaging (MSI) is a versatile tool for visualizing molecular distributions in complex biological specimens, but locating microscopic chemical features of interest can be challenging samples that lack well-defined anatomy. To address this issue, we developed correlated approach begins with performing matrix-assisted laser desorption/ionization (MALDI) MSI to obtain low-resolution maps sample. The resulting are then used direct subsequent secondary ion mass (SIMS) and tandem...

Significance The opportunistic pathogen Pseudomonas aeruginosa utilizes both its flagellum and type IV pili (TFP) to facilitate motility, attachment, colonization. Surface motility such as swarming is thought precede biofilm formation during infection. We combined laboratory computational methods probe the physical interactions of TFP flagellar-mediated found that one cell strongly interact with other cells, which limits expansion rate. Hence, wild-type P. use cell−cell via their control...

Nontypeable Haemophilus influenzae (NTHi) commonly causes otitis media, chronic bronchitis in emphysema, and early airway infections cystic fibrosis. Long-term, low-dose azithromycin has been shown to improve clinical outcomes lung diseases, although the mechanism of action remains unclear. The inhibition bacterial biofilms by postulated be one mediating these effects. We hypothesized that subinhibitory concentrations would affect NTHi biofilm formation. Laboratory strains expressing green...

DNA is a common extracellular matrix component of bacterial biofilms. We find that bacteria can spontaneously order in aligned concentrated DNA, which rod-shaped cells Pseudomonas aeruginosa follow the orientation extended chains. The alignment ensured by elasticity and liquid crystalline properties matrix. These findings show how behavior planktonic may be modified polymeric substances biofilms illustrate potential using complex fluids to manipulate embedded nanosized microsized active particles.

Many bacteria spread over surfaces by "swarming" in groups. A problem for scientists who study swarming is the acquisition of statistically significant data that distinguish two observations or detail temporal patterns and two-dimensional heterogeneities occur. It currently difficult to quantify differences between observed swarm phenotypes. Here, we present a method surface motility using time-lapse fluorescence bioluminescence imaging. We specifically demonstrate three applications our...

Raman and SIMS imaging elucidate the spatial temporal organization of quinolones in P. aeruginosa colonies on agar, planktonic cells, static biofilms.

Bacterial surface motility, such as swarming, is commonly examined in the laboratory using plate assays that necessitate specific concentrations of agar and sometimes inclusion nutrients growth medium. The preparation explicit media conditions serves to provide favorable allow not just bacterial but coordinated motility bacteria over these surfaces within thin liquid films. Reproducibility swarm other can be a major challenge. Especially for more "temperate swarmers" exhibit only ranges...

Secondary ion mass spectrometry (SIMS) and confocal Raman microscopy (CRM) are combined to analyze the chemical composition of cultured Pseudomonas aeruginosa biofilms, providing complementary information for multiple analytes within sample. Precise spatial correlation between SIMS CRM images is achieved by applying a microdroplet array sample surface which used navigate sample, relocate regions interest, align image data. then employed nondestructively detect broad molecular constituent...

ABSTRACT The degree to which surface-motile bacteria explore their surroundings is influenced by aspects of local environment. Accordingly, the regulation surface motility controlled numerous chemical, physical, and biological stimuli. discernment such due these multiple cues a formidable challenge. Additionally, inherent ambiguity variability from assays used assess can be obstacles clear delineation regulated behavior. Numerous studies have reported single environmental determinants...

The chemical composition of bacterial biofilms is explored and visualized with the combination two label-free molecular imaging techniques.

Surface enhanced Raman spectroscopy (SERS) imaging was used in conjunction with principal component analysis (PCA) for the situ spatiotemporal mapping of virulence factor pyocyanin communities pathogenic bacterium Pseudomonas aeruginosa. The combination SERS and PCA provides a robust method characterization heterogeneous biological systems while circumventing issues associated interference from sample autofluorescence low reproducibility signals. production is found to depend both on growth...

The importance of rhamnolipid to swarming the bacterium Pseudomonas aeruginosa is well established. It frequently, but not exclusively, observed that P. swarms in tendril patterns—formation these tendrils requires rhamnolipid. We were interested explain impact surface changes on swarm development. Here we report quorum sensing and production impaired when growing harder semi-solid surfaces. wild-type showed huge variation formation with small deviations "standard" agar concentration 0.5%....

We recently demonstrated that Pseudomonas aeruginosa PAO1 undergoes a pronounced phenotypic change when introduced into the intestines of rats during surgical injury. Recovered strains displayed specific phenotype (termed P2 phenotype) characterized by altered pyocyanin production, high collagenase activity, swarming motility, low resistance to chloramphenicol, and increased killing Caenorhabditis elegans compared inoculating strain P1 phenotype). The aims this study were characterize...