biofilms
Enzymology and Protein EngineeringTat-Dependent Heterologous Secretion of Recombinant Tyrosinase by Pseudomonas fluorescens Is Aided by a Translationally Fused Caddie ProteinWe observed that the S. antibioticus extracellular tyrosinase secretion level was even higher in its nonnatural translationally conjugated fusion protein form than in the natural complex of two separated polypeptides. The results of this study demonstrate that tyrosinase-expressing P. fluorescens can be a stable source of bacterial tyrosinase through...
MethodsLuminescent Nanosensors for Ratiometric Monitoring of Three-Dimensional Oxygen Gradients in Laboratory and Clinical Pseudomonas aeruginosa BiofilmsBiofilm infections are more difficult to treat than planktonic infections for a variety of reasons, such as decreased antibiotic penetration. Their complex structure makes biofilms challenging to study without disruption. To address this limitation, we developed and demonstrated oxygen-sensitive luminescent nanosensors that can be incorporated into biofilms for studying oxygen penetration, distribution, and antibiotic efficacy—...
Public and Environmental Health MicrobiologyMotility-Independent Formation of Antibiotic-Tolerant Pseudomonas aeruginosa AggregatesIn this work, we have investigated the role of bacterial motility with regard to antibiotic-tolerant bacterial aggregate formation. Previous work has convincingly demonstrated that P. aeruginosa flagellar motility promotes the formation of surface-adhered biofilms in many systems. In contrast, aggregate formation by...
Environmental MicrobiologyThe Plant Host Induces Antibiotic Production To Select the Most-Beneficial ColonizersOur study sheds mechanistic light on how multicellular biofilm units compete to successfully colonize a eukaryote host, using B. subtilis microbial communities as our lens. The microbiota and its interactions with its host play various roles in the development and prevention of diseases. Using competing beneficial biofilms that are essential microbiota members on the...
Biotechnology | SpotlightCongo Red Fluorescence for Rapid In Situ Characterization of Synthetic Curli SystemsCurli are proteins produced by many bacteria as a structural component of biofilms, and they have recently emerged as a platform for fabrication of biological materials. Curli fibers are very robust and resistant to degradation, and the curli subunits can tolerate many protein fusions, facilitating the biosynthesis of novel functional materials. A serious bottleneck in the development of more sophisticated engineered curli systems is...
Environmental Microbiology | SpotlightDeep-Subsurface Pressure Stimulates Metabolic Plasticity in Shale-Colonizing Halanaerobium spp.The hydraulic fracturing of deep-shale formations for hydrocarbon recovery accounts for approximately 60% of U.S. natural gas production. Microbial activity associated with this process is generally considered deleterious due to issues associated with sulfide production, microbially induced corrosion, and bioclogging in the subsurface. Here we demonstrate that a representative Halanaerobium species, frequently the dominant...
Genetics and Molecular BiologyAxenic Biofilm Formation and Aggregation by Synechocystis sp. Strain PCC 6803 Are Induced by Changes in Nutrient Concentration and Require Cell Surface StructuresMicrobes can exist as suspensions of individual cells in liquids and also commonly form multicellular communities attached to surfaces. Surface-attached communities, called biofilms, can confer antibiotic resistance to pathogenic bacteria during infections and establish food webs for global nutrient cycling in the environment. Phototrophic biofilm formation is one of the earliest phenotypes visible in the fossil record, dating back over...
Genetics and Molecular BiologyMolecular and Functional Analysis of the Type IV Pilus Gene Cluster in Streptococcus sanguinis SK36The proteins and assembly machinery of the type IV pili (Tfp) are conserved throughout bacteria and archaea, and yet the function of this surface structure differs from species to species and even from strain to strain. As seen in Streptococcus sanguinis SK36, the expression of the Tfp gene cluster results in a hairlike surface structure that is much shorter than the...
Genetics and Molecular BiologyGlycosyltransferase-Mediated Biofilm Matrix Dynamics and Virulence of Streptococcus mutansTooth decay, a costly and painful disease affecting the vast majority of people worldwide, is caused by the bacterium Streptococcus mutans. The bacteria utilize dietary sugars to build and strengthen biofilms, trapping acids onto the tooth’s surface and causing demineralization and decay of teeth. As knowledge of our body’s microbiomes increases, the need for...
Microbial EcologyEffects of Antimicrobial Peptide GH12 on the Cariogenic Properties and Composition of a Cariogenic Multispecies BiofilmDental caries is one of the most prevalent chronic infectious diseases worldwide, with substantial economic and quality-of-life impacts. Streptococcus mutans has been considered the principal pathogen of dental caries. To combat dental caries, an antimicrobial peptide, GH12, was designed, and its antibacterial effects on planktonic...