Complementation of Sulfolobus solfataricus PBL2025 with an α-mannosidase: effects on surface attachment and biofilm formation

Pseudomonas fluorescens Pf0-1 is one of the model organisms for biofilm research. Our previous transposon mutagenesis study suggested a requirement for the de novo purine nucleotide biosynthesis pathway for biofilm formation by this organism. This study was performed to verify that observation and investigate the basis for the defects in biofilm formation shown by purine biosynthesis mutants. Constructing deletion mutations in 8 genes in this pathway, we found that they all showed reductions in biofilm formation that could be partly or completely restored by nucleotide supplementation or genetic complementation. We demonstrated that, despite a reduction in biofilm formation, more viable mutant cells were recovered from the surface-attached population than from the planktonic phase under conditions of purine deprivation. Analyses using scanning electron microscopy revealed that the surface-attached mutant cells were 25~30% shorter in length than WT, which partly explains the reduced biomass in the mutant biofilms. The laser diffraction particle analyses confirmed this finding, and further indicated that the WT biofilm cells were smaller than their planktonic counterparts. The defects in biofilm formation and reductions in cell size shown by the mutants were fully recovered upon adenine or hypoxanthine supplementation, indicating that the purine shortages caused reductions in cell size. Our results are consistent with surface attachment serving as a survival strategy during nutrient deprivation, and indicate that changes in the cell size may be a natural response of P. fluorescens to growth on a surface. Finally, cell sizes in WT biofilms became slightly smaller in the presence of exogenous adenine than in its absence. Our findings suggest that purine nucleotides or related metabolites may influence the regulation of cell size in this bacterium.

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Investigation of synovial fluid induced Staphylococcus aureus aggregate development and its impact on surface attachment and biofilm formation

PLoS ONE ◽

10.1371/journal.pone.0231791 ◽

2020 ◽

Vol 15 (4) ◽

pp. e0231791 ◽

Cited By ~ 3

Author(s):

Matthew J. Pestrak ◽

Tripti Thapa Gupta ◽

Devendra H. Dusane ◽

Doug V. Guzior ◽

Amelia Staats ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Synovial Fluid ◽

Biofilm Formation ◽

Surface Attachment

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Baicalein Inhibits Streptococcus mutans Biofilms and Dental Caries-Related Virulence Phenotypes

Antibiotics ◽

10.3390/antibiotics10020215 ◽

2021 ◽

Vol 10 (2) ◽

pp. 215

Author(s):

Aparna Vijayakumar ◽

Hema Bhagavathi Sarveswari ◽

Sahana Vasudevan ◽

Karthi Shanmugam ◽

Adline Princy Solomon ◽

...

Keyword(s):

Dental Caries ◽

Streptococcus Mutans ◽

Biofilm Formation ◽

Acid Production ◽

Cell Surface Hydrophobicity ◽

Surface Hydrophobicity ◽

Oral Disease ◽

Public Healthcare ◽

Surface Attachment ◽

First Time

Dental caries, the most common oral disease, is a major public healthcare burden and affects more than three billion people worldwide. The contemporary understanding of the need for a healthy microbiome and the emergence of antimicrobial resistance has resulted in an urgent need to identify compounds that curb the virulence of pathobionts without microbial killing. Through this study, we have demonstrated for the first time that 5,6,7-trihydroxyflavone (Baicalein) significantly downregulates crucial caries-related virulence phenotypes in Streptococcus mutans. Baicalein significantly inhibited biofilm formation by Streptococcus mutans UA159 (MBIC50 = 200 μM), without significant growth inhibition. Notably, these concentrations of baicalein did not affect the commensal S. gordonii. Strikingly, baicalein significantly reduced cell surface hydrophobicity, autoaggregation and acid production by S. mutans. Mechanistic studies (qRT-PCR) showed downregulation of various genes regulating biofilm formation, surface attachment, quorum sensing, acid production and competence. Finally, we demonstrate the potential translational value of baicalein by reporting synergistic interaction with fluoride against S. mutans biofilms.

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Chicken Juice Enhances Surface Attachment and Biofilm Formation of Campylobacter jejuni

Applied and Environmental Microbiology ◽

10.1128/aem.02614-14 ◽

2014 ◽

Vol 80 (22) ◽

pp. 7053-7060 ◽

Cited By ~ 68

Author(s):

Helen L. Brown ◽

Mark Reuter ◽

Louise J. Salt ◽

Kathryn L. Cross ◽

Roy P. Betts ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Food Chain ◽

Biofilm Formation ◽

Cell Attachment ◽

Bacterial Attachment ◽

Poultry Meat ◽

Abiotic Surface ◽

Surface Attachment ◽

Aerobic Conditions ◽

Content Type

ABSTRACTThe bacterial pathogenCampylobacter jejuniis primarily transmitted via the consumption of contaminated foodstuffs, especially poultry meat. In food processing environments,C. jejuniis required to survive a multitude of stresses and requires the use of specific survival mechanisms, such as biofilms. An initial step in biofilm formation is bacterial attachment to a surface. Here, we investigated the effects of a chicken meat exudate (chicken juice) onC. jejunisurface attachment and biofilm formation. Supplementation of brucella broth with ≥5% chicken juice resulted in increased biofilm formation on glass, polystyrene, and stainless steel surfaces with fourC. jejuniisolates and oneC. coliisolate in both microaerobic and aerobic conditions. When incubated with chicken juice,C. jejuniwas both able to grow and form biofilms in static cultures in aerobic conditions. Electron microscopy showed thatC. jejunicells were associated with chicken juice particulates attached to the abiotic surface rather than the surface itself. This suggests that chicken juice contributes toC. jejunibiofilm formation by covering and conditioning the abiotic surface and is a source of nutrients. Chicken juice was able to complement the reduction in biofilm formation of an aflagellated mutant ofC. jejuni, indicating that chicken juice may support food chain transmission of isolates with lowered motility. We provide here a useful model for studying the interaction ofC. jejunibiofilms in food chain-relevant conditions and also show a possible mechanism forC. jejunicell attachment and biofilm initiation on abiotic surfaces within the food chain.

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Cryptococcal Traits Mediating Adherence to Biotic and Abiotic Surfaces

Journal of Fungi ◽

10.3390/jof4030088 ◽

2018 ◽

Vol 4 (3) ◽

pp. 88 ◽

Cited By ~ 6

Author(s):

Emma Camacho ◽

Arturo Casadevall

Keyword(s):

Biofilm Formation ◽

Microbial Pathogenesis ◽

Structural Components ◽

Surface Attachment ◽

Mortality And Morbidity ◽

Fungal Adhesion ◽

Adaptation Mechanisms ◽

Abiotic Surfaces ◽

Animal Hosts ◽

Cryptococcus Spp

Several species in the genus Cryptococcus are facultative intracellular pathogens capable of causing disease associated with high mortality and morbidity in humans. These fungi interact with other organisms in the soil, and these interactions may contribute to the development of adaptation mechanisms that function in virulence by promoting fungal survival in animal hosts. Fungal adhesion molecules, also known as adhesins, have been classically considered as cell-surface or secreted proteins that play critical roles in microbial pathogenesis or in biofilm formation as structural components. Pathogenic Cryptococcus spp. differ from other pathogenic yeasts in having a polysaccharide capsule that covers the cell wall surface and precludes interactions of those structures with host cell receptors. Hence, pathogenic Cryptococcus spp. use unconventional tools for surface attachment. In this essay, we review the unique traits and mechanisms favoring adhesion of Cryptococcus spp. to biotic and abiotic surfaces. Knowledge of the traits that mediate adherence could be exploited in the development of therapeutic, biomedical, and/or industrial products.

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IscR Controls Iron-Dependent Biofilm Formation in Escherichia coli by Regulating Type I Fimbria Expression

Journal of Bacteriology ◽

10.1128/jb.01086-08 ◽

2008 ◽

Vol 191 (4) ◽

pp. 1248-1257 ◽

Cited By ~ 92

Author(s):

Yun Wu ◽

F. Wayne Outten

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Developmental Process ◽

Bacterial Species ◽

Type I ◽

Surface Attachment ◽

Environmental Signals ◽

Regulatory Pathways ◽

E Coli ◽

Type I Fimbriae

ABSTRACT Biofilm formation is a complex developmental process regulated by multiple environmental signals. In addition to other nutrients, the transition metal iron can also regulate biofilm formation. Iron-dependent regulation of biofilm formation varies by bacterial species, and the exact regulatory pathways that control iron-dependent biofilm formation are often unknown or only partially characterized. To address this gap in our knowledge, we examined the role of iron availability in regulating biofilm formation in Escherichia coli. The results indicate that biofilm formation is repressed under low-iron conditions in E. coli. Furthermore, a key iron regulator, IscR, controls biofilm formation in response to changes in cellular Fe-S homeostasis. IscR regulates the FimE recombinase to control expression of type I fimbriae in E. coli. We propose that iron-dependent regulation of FimE via IscR leads to decreased surface attachment and biofilm dispersal under iron-limiting conditions.

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Advanced understanding of prokaryotic biofilm formation using a cost-effective and versatile multi-panel adhesion (mPAD) mount

Applied and Environmental Microbiology ◽

10.1128/aem.02283-21 ◽

2022 ◽

Author(s):

Stefan Schulze ◽

Heather Schiller ◽

Jordan Solomonic ◽

Orkan Telhan ◽

Kyle Costa ◽

...

Keyword(s):

Biofilm Formation ◽

Cost Effective ◽

Flow Chamber ◽

Culture Conditions ◽

Multiple Time ◽

Wild Type ◽

Surface Attachment ◽

Flowing Liquid ◽

Multiple Time Points ◽

Static Conditions

Most microorganisms exist in biofilms, which comprise aggregates of cells surrounded by an extracellular matrix that provides protection from external stresses. Based on the conditions under which they form, biofilm structures vary in significant ways. For instance, biofilms that develop when microbes are incubated under static conditions differ from those formed when microbes encounter the shear forces of a flowing liquid. Moreover, biofilms develop dynamically over time. Here, we describe a cost-effective, 3D-printed coverslip holder that facilitates surface adhesion assays under a broad range of standing and shaking culture conditions. This multi-panel adhesion (mPAD) mount further allows cultures to be sampled at multiple time points, ensuring consistency and comparability between samples and enabling analyses of the dynamics of biofilm formation. As a proof of principle, using the mPAD mount for shaking, oxic cultures, we confirm previous flow chamber experiments showing that Pseudomonas aeruginosa wild type and a phenazine deletion mutant (Δ phz ) form biofilms with similar structure but reduced density in the mutant strain. Extending this analysis to anoxic conditions, we reveal that microcolony and biofilm formation can only be observed under shaking conditions and are decreased in the Δ phz mutant compared to wild-type cultures, indicating that phenazines are crucial for the formation of biofilms if oxygen as an electron acceptor is unavailable. Furthermore, while the model archaeon Haloferax volcanii does not require archaella for surface attachment under static conditions, we demonstrate that H. volcanii mutants that lack archaella are impaired in early stages of biofilm formation under shaking conditions. Importance: Due to the versatility of the mPAD mount, we anticipate that it will aid the analysis of biofilm formation in a broad range of bacteria and archaea. Thereby, it contributes to answering critical biological questions about the regulatory and structural components of biofilm formation and understanding this process in a wide array of environmental, biotechnological, and medical contexts.

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Modulation of Flagellar Rotation in Surface-Attached Bacteria: A Circuit for Rapid Surface-Sensing

10.1101/567438 ◽

2019 ◽

Cited By ~ 1

Author(s):

Maren Schniederberend ◽

Jessica F. Johnston ◽

Emilee Shine ◽

Cong Shen ◽

Ruchi Jain ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Second Messenger ◽

Switching Behavior ◽

Scaffolding Protein ◽

Polar Flagellum ◽

Initial Contact ◽

Surface Attachment ◽

Attached Bacteria ◽

Flagellar Rotation

AbstractAttachment is a necessary first step in bacterial commitment to surface-associated behaviors that include colonization, biofilm formation, and host-directed virulence. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa can initially attach to surfaces via its single polar flagellum. Although many bacteria quickly detach, some become irreversibly attached and express surface-associated structures, such as Type IV pili, and behaviors, including twitching motility and biofilm initiation. P. aeruginosa that lack the GTPase FlhF assemble a randomly placed flagellum that is motile; however, we observed that these mutant bacteria show defects in biofilm formation comparable to those seen for non-motile, aflagellate bacteria. This phenotype was associated with altered behavior of ΔflhF bacteria immediately following surface-attachment. Forward and reverse genetic screens led to the discovery that FlhF interacts with FimV to control flagellar rotation at a surface, and implicated cAMP signaling in this pathway. Although cAMP controls many transcriptional programs in P. aeruginosa, the known targets of this second messenger were not required to modulate flagellar rotation in surface-attached bacteria. Instead, alterations in switching behavior of the motor appear to result from previously undescribed effects of cAMP on switch complex proteins and/or the motor-stators associated with them.Author SummaryAttachment to a surface often triggers programs of gene expression that alter the behavior, virulence and fitness of bacteria. Initial contact is usually mediated by surface exposed adhesins, such as flagella or pili/fimbriae, and there is much interest in how these structures might sense and respond to surface attachment. The human bacterial pathogen Pseudomonas aeruginosa usually contacts surfaces via its polar flagellum, the rotary motor that also powers bacterial swimming. We observed that wild-type bacteria quickly stopped rotating their flagellum after surface attachment, but that a mutant lacking the flagellar-associated protein FlhF did not. Using a combination of genetic approaches, we demonstrated that FlhF interacts with a component of the flagellar rotor (FliG) and with a polar scaffolding protein that positively regulates cAMP production (FimV) to stop flagellar rotation and thereby favor bacterial persistence at a surface. We provide evidence that the second messenger cAMP is the likely signal generated by flagellar-mediated surface attachment and show that cAMP is sufficient to alter the behavior of the flagellar motor.

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The two chemotaxis inCaulobacter crescentusoperons play different roles in chemotaxis and biofilm regulation

10.1101/528224 ◽

2019 ◽

Author(s):

Cécile Berne ◽

Yves V. Brun

Keyword(s):

Biofilm Formation ◽

Caulobacter Crescentus ◽

Carbon Sources ◽

Synthesis Inhibitor ◽

Gene Encoding ◽

Surface Attachment ◽

Transduction Mechanisms ◽

Chemotaxis Proteins ◽

Positive Regulators ◽

Chemosensory Pathways

ABSTRACTThe holdfast polysaccharide adhesin is crucial for irreversible cell adhesion and biofilm formation inCaulobacter crescentus. Holdfast production is tightly controlled via developmental regulators, and environmental and physical signals. Here we identified a novel mechanism of holdfast production regulation that involves chemotaxis proteins. We characterized the two identified chemotaxis operons ofC. crescentusand showed that only the previously characterized, major operon is involved in chemotactic response towards different carbon sources. However, both chemotaxis operons encoded in theC. crescentusgenome play a role in biofilm formation and holdfast production, by regulating the expression ofhfiA, the gene encoding the holdfast inhibitor HfiA. We show that CheA and CheB proteins act in an antagonistic manner: while the two CheA proteins negatively regulatehfiAexpression, the CheB proteins are positive regulators, thus providing a modulation of holdfast synthesis and surface attachment.IMPORTANCEChemosensory pathways are major signal transduction mechanisms in bacteria. These systems are involved in chemotaxis and other cell responses to environment conditions, such as production of adhesins that enable irreversible adhesion to a surface and surface colonization. TheC. crescentusgenome encodes two complete chemotaxis operons. Here we characterized the second, novel chemotaxis-like operon. While only the major chemotaxis operon is involved in chemotaxis, both chemotaxis systems modulateC. crescentusadhesion by controlling expression of the holdfast synthesis inhibitor, HfiA. Thus, we identified a new level in holdfast regulation, providing new insights into the control of adhesin production that leads to the formation of biofilms.

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Polymer Adhesin Domains in Gram-Positive Cell Surface Proteins

Frontiers in Microbiology ◽

10.3389/fmicb.2020.599899 ◽

2020 ◽

Vol 11 ◽

Author(s):

Michael A. Järvå ◽

Helmut Hirt ◽

Gary M. Dunny ◽

Ronnie P.-A. Berntsson

Keyword(s):

Protein Function ◽

Biofilm Formation ◽

Lipoteichoic Acid ◽

Surface Proteins ◽

Protein Domain ◽

Gram Positive ◽

Surface Attachment ◽

Gram Positive Bacteria ◽

Different Types ◽

Host Cell Interactions

Surface proteins in Gram-positive bacteria are often involved in biofilm formation, host-cell interactions, and surface attachment. Here we review a protein module found in surface proteins that are often encoded on various mobile genetic elements like conjugative plasmids. This module binds to different types of polymers like DNA, lipoteichoic acid and glucans, and is here termed polymer adhesin domain. We analyze all proteins that contain a polymer adhesin domain and classify the proteins into distinct classes based on phylogenetic and protein domain analysis. Protein function and ligand binding show class specificity, information that will be useful in determining the function of the large number of so far uncharacterized proteins containing a polymer adhesin domain.

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