biofilm formation only partially predicts beneficial protection against rhizosphere pathogens.

Plant roots form associations with both beneficial and pathogenic soil microorganisms. While members of the rhizosphere microbiome can protect against pathogens, the mechanisms are poorly understood. We hypothesized that the ability to form a robust biofilm on the root surface is necessary for the exclusion of pathogens; however, it is not known if the same biofilm formation components required are necessary WCS365 is a beneficial strain that is phylogenetically closely related to an opportunistic pathogen N2C3 and confers robust protection against N2C3 in the rhizosphere.

Organoclay flocculation as a pathway to export carbon from the sea surface.

Marine microorganisms play a critical role in regulating atmospheric CO concentration via the biological carbon pump. Deposition of continental mineral dust on the sea surface increases carbon sequestration but the interaction between minerals and marine microorganisms is not well understood. We discovered that the interaction of clay minerals with dissolved organic matter and a γ-proteobacterium in seawater increases Transparent Exopolymer Particle (TEP) concentration, leading to organoclay floc formation.

supports the survival of in a cystic fibrosis lung polymicrobial community through metabolic cross-feeding.

Cystic fibrosis (CF) is a multi-organ genetic disorder that affects more than 100,000 individuals worldwide. Chronic respiratory infections are among the hallmark complications associated with CF lung disease, and these infections are often due to polymicrobial communities that colonize the airways of persons with CF (pwCF). Such infections are a significant cause of morbidity and mortality, with studies indicating that pwCF who are co-infected with more than one organism experience more frequent pulmonary exacerbations, leading to a faster decline in lung function.

Quantifying Forms and Functions of Enterohepatic Bile Acid Pools in Mice.

Backgrounds & Aims: Bile acids (BAs) are core gastrointestinal metabolites with dual functions in lipid absorption and cell signaling. BAs circulate between the liver and distal small intestine (i.e.

Premodulator microbiome alterations associated with postmodulator growth outcomes in pediatric cystic fibrosis: Can we predict outcomes?

Objectives: The gut microbiota plays an important role in childhood growth. Our longitudinal cohort includes children with cystic fibrosis (CwCF) treated with highly effective modulator therapy. We aimed to elucidate early premodulator microbial signatures associated with postmodulator weight for CwCF later in childhood.

Atomic force microscopy analysis of Pel polysaccharide- and type IV pili-mediated adhesion of PA14 to an abiotic surface.

Type IV pili (TFP) contribute to the ability of microbes such as to engage with and move across surfaces. We reported previously that TFP generate retractive forces of ∼30 pN and provided indirect evidence that TFP-mediated surface attachment was enhanced in the presence of the Pel polysaccharide. Here, we use different mutants defective in flagellar, Pel production or TFP production - alone or in combination - to decipher the relative contribution of these biofilm-promoting factors for adhesion.

Multiple pathways impact the swarming motility of Pf0-1.

Swarming motility in pseudomonads typically requires both a functional flagellum and the production/secretion of a biosurfactant. Published work has shown that the wild-type Pf0-1 is swarming deficient due to a point mutation in the gene, which until recently was thought to inactivate rather than attenuate the Gac/Rsm pathway. As a result, little is known about the underlying mechanisms that regulate swarming motility by Pf0-1.

Local control: a hub-based model for the c-di-GMP network.

The genome of encodes >50 proteins predicted to play a role in bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP)-mediated biofilm formation. We built a network representation of protein-protein interactions and extracted key information via multidimensional scaling (i.e.

Reconstitution of a biofilm adhesin system from a sulfate-reducing bacterium in .

Biofilms of sulfate-reducing bacterium (SRB) like Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to substantial economic losses. Although the mechanisms of biofilm formation by DvH are not yet well understood, recent studies indicate the large adhesin, DvhA, is a key determinant of biofilm formation. The gene neighborhood resembles the biofilm-regulating Lap system of but is curiously missing the c-di-GMP-binding regulator LapD.

How cells with diverse stator composition collectively swarm.

Swarming is a macroscopic phenomenon in which surface bacteria organize into a motile population. The flagellar motor that drives swarming in is powered by stators MotAB and MotCD. Deletion of the MotCD stator eliminates swarming, whereas deletion of the MotAB stator enhances swarming.

Quantifying forms and functions of intestinal bile acid pools in mice.

Bile acids (BAs) are gastrointestinal metabolites that serve dual functions in lipid absorption and cell signaling. BAs circulate actively between the liver and distal small intestine (i.e.

Multiple Pathways Impact Swarming Motility of Pf0-1.

Swarming motility in pseudomonads typically requires both a functional flagellum and production/secretion of a biosurfactant. Published work has shown that the wild-type Pf0-1 is swarming-deficient due to a point mutation in the gene, which until recently, was thought to inactivate rather than attenuate the Gac/Rsm pathway. As a result, little is known about the underlying mechanisms that regulate swarming motility by Pf0-1.

Intestinal modulates inflammation, systemic cytokines, and microbial ecology via propionate in a mouse model of cystic fibrosis.

Persons with cystic fibrosis (CF), starting in early life, show intestinal microbiome dysbiosis characterized in part by a decreased relative abundance of the genus is a major producer of the intestinal short chain fatty acid propionate. We demonstrate here that cystic fibrosis transmembrane conductance regulator-defective (CFTR-/-) Caco-2 intestinal epithelial cells are responsive to the anti-inflammatory effects of propionate. Furthermore, isolates inhibit the IL-1β-induced inflammatory response of CFTR-/- Caco-2 intestinal epithelial cells and do so in a propionate-dependent manner.

An medium for modeling gut dysbiosis associated with cystic fibrosis.

The gut physiology of pediatric and adult persons with cystic fibrosis (pwCF) is altered relative to healthy persons. The CF gut is characterized, in part, as having excess mucus, increased fat content, acidic pH, increased inflammation, increased antibiotic perturbation, and the potential for increased oxygen availability. These physiological differences shift nutritional availability and the local environment for intestinal microbes, thus likely driving significant changes in microbial metabolism, colonization, and competition with other microbes.

Reconstitution of a Biofilm Adhesin System from a Sulfate-Reducing Bacterium in .

Biofilms of the sulfate reducing bacterium (SRB) Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to substantial economic losses; however, the mechanisms of biofilm formation by DvH are not yet well-understood. Evidence suggests that a large adhesin, DvhA, may be contributing to biofilm formation in DvH. The gene and its neighbors encode proteins that resemble the Lap system, which regulates biofilm formation by , including a LapG-like protease DvhG and effector protein DvhD, which has key differences from the previously described LapD.

Antibacterial Efficacy of Manuka Honey-Doped Chitosan-Gelatin Cryogel and Hydrogel Scaffolds in Reducing Infection.

Honey has been used for centuries to reduce bacterial infection; Manuka honey (MH) possesses an additional antibacterial agent, Unique Manuka Factor (UMF). However, MH's physical properties challenge delivery to the wound site. Tissue-engineered scaffolds (cryogels/hydrogels) provide a potential vehicle for MH delivery, but effects on bacterial clearance and biofilm formation demand further examination.

The accumulation and growth of Pseudomonas aeruginosa on surfaces is modulated by surface mechanics via cyclic-di-GMP signaling.

Attachment of bacteria onto a surface, consequent signaling, and accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that surface mechanics may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of surface mechanics and modulation of accumulation in response to surface mechanics remain largely unknown. We use thin and thick hydrogels coated on glass to create composite materials with different mechanics (higher elasticity for thin composites; lower elasticity for thick composites) but with the same surface adhesivity and chemistry.

Transcriptional profiling and genetic analysis of a cystic fibrosis airway-relevant model shows asymmetric responses to growth in a polymicrobial community.

Bacterial infections in the lungs of persons with cystic fibrosis are typically composed of multispecies biofilm-like communities, which modulate clinically relevant phenotypes that cannot be explained in the context of a single species culture. Most analyses to date provide a picture of the transcriptional responses of individual pathogens; however, there is relatively little data describing the transcriptional landscape of clinically relevant multispecies communities. Harnessing a previously described cystic fibrosis-relevant, polymicrobial community model consisting of and , we performed an RNA-Seq analysis on the biofilm population to elucidate the transcriptional profiles of the community grown in artificial sputum medium (ASM) as compared to growth in monoculture, without mucin, and in fresh medium supplemented with tobramycin.

The regulator FleQ both transcriptionally and post-transcriptionally regulates the level of RTX adhesins of .

Biofilm formation by the Gram-negative, Gammaproteobacteria relies on the repeats-in-toxin adhesins LapA and MapA in the cytoplasm, secretion of these adhesins through their respective type 1 secretion systems, and retention at the cell surface. Published work has shown that retention of the adhesins occurs via a post-translational mechanism involving the cyclic-di-GMP receptor LapD and the protease LapG. However, little is known about the underlying mechanisms that regulate the level of these adhesins.

An In Vitro Medium for Modeling Gut Dysbiosis Associated with Cystic Fibrosis.

The gut physiology of pediatric and adult persons with cystic fibrosis (pwCF) is altered relative to healthy persons. The CF gut is characterized, in part, as having excess mucus, increased fat content, acidic pH, increased inflammation, increased antibiotic perturbation and the potential for increased oxygen availability. These physiological differences shift nutritional availability and the local environment for intestinal microbes, thus likely driving significant changes in microbial metabolism, colonization and competition with other microbes.

Assessment of the Glycan-Binding Profile of Pseudomonas aeruginosa PAO1.

Pseudomonas aeruginosa is an opportunistic pathogen that can establish acute and chronic infections in individuals who lack fully functional innate immunity. In particular, phagocytosis by neutrophils and macrophages is a key mechanism that modulates host control and clearance of P. aeruginosa.