Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility.

Correlated imaging with C60-SIMS and confocal Raman microscopy: Visualization of cell-scale molecular distributions in bacterial biofilms.

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

MALDI-guided SIMS: multiscale imaging of metabolites in bacterial biofilms.

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 in samples that lack a well-defined anatomy. To address this issue, we developed a correlated imaging approach that begins with performing matrix-assisted laser desorption/ionization (MALDI) MSI to obtain low-resolution molecular maps of a sample. The resulting maps are then used to direct subsequent microscopic secondary ion mass spectrometry (SIMS) imaging and tandem mass spectrometry (MS/MS) experiments to examine selected chemical regions of interest.

Spatial organization of Pseudomonas aeruginosa biofilms probed by combined matrix-assisted laser desorption ionization mass spectrometry and confocal Raman microscopy.

Bacteria growing as surface attached biofilms differ significantly from planktonic cells in several important traits that are reflected in the spatiotemporal organization of the cells and the extracellular polymeric substances they secrete. The structural and chemical features that define these biofilms are explored here using a combination of matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) and confocal Raman microspectroscopies (CRM) to characterize and compare the composition and distribution of biomolecules found in biofilms and planktonic cells of the bacterium Pseudomonas aeruginosa. Three-day old P.