scholarly journals Biofilm hydrophobicity in environmental isolates of Bacillus subtilis

2021 ◽  
Author(s):  
Margarita Kalamara ◽  
James C. Abbott ◽  
Cait E. MacPhee ◽  
Nicola. R. Stanley-Wall
Keyword(s):  
Extracellular Matrix ◽  
Bacillus Subtilis ◽  
Glutamic Acid ◽  
Biofilm Formation ◽  
Environmental Isolates ◽  
Diverse Range ◽  
European Nucleotide Archive ◽  
Universal Feature ◽  
The Matrix ◽  
Highly Hydrophobic

AbstractBiofilms are communities of bacteria that are attached to a surface and surrounded by an extracellular matrix. The extracellular matrix protects the community from stressors in the environment, making biofilms robust. The Gram-positive soil bacterium Bacillus subtilis, particularly the isolate NCIB 3610, is widely used as a model for studying biofilm formation. B. subtilis NCIB 3610 forms colony biofilms that are architecturally complex and highly hydrophobic. The hydrophobicity is linked, in part, to the localisation of the protein BslA at the surface of the biofilm, which provides the community with increased resistance to biocides. As most of our knowledge about B. subtilis biofilm formation comes from one isolate, it is unclear if biofilm hydrophobicity is a widely distributed feature of the species. To address this knowledge gap, we collated a library of B. subtilis soil isolates and acquired their whole genome sequences. We used our new isolates to examine biofilm hydrophobicity and found that, although BslA is encoded and produced by all isolates in our collection, hydrophobicity is not a universal feature of B. subtilis colony biofilms. To test whether the matrix exopolymer poly γ-glutamic acid could be masking hydrophobicity in our hydrophilic isolates, we constructed deletion mutants and found, contrary to our hypothesis, that the presence of poly γ-glutamic acid was not the reason behind the observed hydrophilicity. This study highlights the natural variation in the properties of biofilms formed by different isolates and the importance of using a more diverse range of isolates as representatives of a species.RepositoriesRaw sequence reads and annotated assemblies have been submitted to the European Nucleotide Archive under accession PRJEB43128.

scholarly journals Biofilm hydrophobicity in environmental isolates of Bacillus subtilis

Microbiology ◽  
2021 ◽  
Vol 167 (9) ◽  
Author(s):  
Margarita Kalamara ◽  
James C. Abbott ◽  
Cait E. MacPhee ◽  
Nicola R. Stanley-Wall
Keyword(s):  
Extracellular Matrix ◽  
Bacillus Subtilis ◽  
Glutamic Acid ◽  
Biofilm Formation ◽  
Type Species ◽  
Diverse Range ◽  
Content Type ◽  
Link Type ◽  
The Matrix ◽  
Highly Hydrophobic

Biofilms are communities of bacteria that are attached to a surface and surrounded by an extracellular matrix. The extracellular matrix protects the community from stressors in the environment, making biofilms robust. The Gram-positive soil bacterium Bacillus subtilis, particularly the isolate NCIB 3610, is widely used as a model for studying biofilm formation. B. subtilis NCIB 3610 forms colony biofilms that are architecturally complex and highly hydrophobic. The hydrophobicity is linked, in part, to the localisation of the protein BslA at the surface of the biofilm, which provides the community with increased resistance to biocides. As most of our knowledge about B. subtilis biofilm formation comes from one isolate, it is unclear if biofilm hydrophobicity is a widely distributed feature of the species. To address this knowledge gap, we collated a library of B. subtilis soil isolates and acquired their whole genome sequences. We used our novel isolates to examine biofilm hydrophobicity and found that, although BslA is encoded and produced by all isolates in our collection, hydrophobicity is not a universal feature of B. subtilis colony biofilms. To test whether the matrix exopolymer poly γ-glutamic acid could be masking hydrophobicity in our hydrophilic isolates, we constructed deletion mutants and found, contrary to our hypothesis, that the presence of poly γ-glutamic acid was not the reason for the observed hydrophilicity. This study highlights the natural variation in the properties of biofilms formed by different isolates and the importance of using a more diverse range of isolates as representatives of a species.

scholarly journals RemA (YlzA) and RemB (YaaB) Regulate Extracellular Matrix Operon Expression and Biofilm Formation in Bacillus subtilis

2009 ◽  
Vol 191 (12) ◽  
pp. 3981-3991 ◽  
Author(s):  
Jared T. Winkelman ◽  
Kris M. Blair ◽  
Daniel B. Kearns
Keyword(s):  
Extracellular Matrix ◽  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Extracellular Polysaccharide ◽  
Pellicle Formation ◽  
Multicellular Aggregates ◽  
The Matrix ◽  
Matrix Components ◽  
Operon Expression ◽  
Motility Inhibition

ABSTRACT Biofilms are multicellular aggregates stabilized by an extracellular matrix. In Bacillus subtilis, the biofilm matrix is composed of an extracellular polysaccharide and the secreted protein TasA. Expression of both of the matrix components is repressed by the DNA-binding master regulator, SinR. Here we identify two small protein regulators of the extracellular matrix: RemA (formerly YlzA) and RemB (formerly YaaB). Mutation of RemA or RemB impairs pellicle formation, complex colony architecture, and motility inhibition in a sinR mutant background. Both proteins are required for the activation of the matrix biosynthesis operons and appear to act in parallel to SinR and two other known biofilm regulators, AbrB and DegU.

scholarly journals Amyloid fibers provide structural integrity to Bacillus subtilis biofilms

2010 ◽  
Vol 107 (5) ◽  
pp. 2230-2234 ◽  
Author(s):  
Diego Romero ◽  
Claudio Aguilar ◽  
Richard Losick ◽  
Roberto Kolter
Keyword(s):  
Extracellular Matrix ◽  
Bacillus Subtilis ◽  
Biological Activity ◽  
Biofilm Formation ◽  
Structural Integrity ◽  
Wild Type ◽  
Amyloid Fibers ◽  
The Matrix ◽  
Biochemical Analyses ◽  
Main Components

Bacillus subtilis forms biofilms whose constituent cells are held together by an extracellular matrix. Previous studies have shown that the protein TasA and an exopolysaccharide are the main components of the matrix. Given the importance of TasA in biofilm formation, we characterized the physicochemical properties of this protein. We report that purified TasA forms fibers of variable length and 10–15 nm in width. Biochemical analyses, in combination with the use of specific dyes and microscopic analyses, indicate that TasA forms amyloid fibers. Consistent with this hypothesis, TasA fibers required harsh treatments (e.g., formic acid) to be depolymerized. When added to a culture of a tasA mutant, purified TasA restored wild-type biofilm morphology, indicating that the purified protein retained biological activity. We propose that TasA forms amyloid fibers that bind cells together in the biofilm.

scholarly journals Galactose Metabolism Plays a Crucial Role in Biofilm Formation by Bacillus subtilis

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Yunrong Chai ◽  
Pascale B. Beauregard ◽  
Hera Vlamakis ◽  
Richard Losick ◽  
Roberto Kolter
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Carbon Sources ◽  
Galactose Metabolism ◽  
Content Type ◽  
Leloir Pathway ◽  
The Matrix ◽  
Living Organisms ◽  
Galactose Metabolites ◽  
Biofilm Matrix

ABSTRACTGalactose is a common monosaccharide that can be utilized by all living organisms via the activities of three main enzymes that make up the Leloir pathway: GalK, GalT, and GalE. InBacillus subtilis, the absence of GalE causes sensitivity to exogenous galactose, leading to rapid cell lysis. This effect can be attributed to the accumulation of toxic galactose metabolites, since thegalEmutant is blocked in the final step of galactose catabolism. In a screen for suppressor mutants restoring viability to agalEnull mutant in the presence of galactose, we identified mutations insinR, which is the major biofilm repressor gene. These mutations caused an increase in the production of the exopolysaccharide (EPS) component of the biofilm matrix. We propose that UDP-galactose is the toxic galactose metabolite and that it is used in the synthesis of EPS. Thus, EPS production can function as a shunt mechanism for this toxic molecule. Additionally, we demonstrated that galactose metabolism genes play an essential role inB. subtilisbiofilm formation and that the expressions of both thegalandepsgenes are interrelated. Finally, we propose thatB. subtilisand other members of theBacillusgenus may have evolved to utilize naturally occurring polymers of galactose, such as galactan, as carbon sources.IMPORTANCEBacteria switch from unicellular to multicellular states by producing extracellular matrices that contain exopolysaccharides. In such aggregates, known as biofilms, bacteria are more resistant to antibiotics. This makes biofilms a serious problem in clinical settings. The resilience of biofilms makes them very useful in industrial settings. Thus, understanding the production of biofilm matrices is an important problem in microbiology. In studying the synthesis of the biofilm matrix ofBacillus subtilis, we provide further understanding of a long-standing microbiological observation that certain mutants defective in the utilization of galactose became sensitive to it. In this work, we show that the toxicity observed before was because cells were grown under conditions that were not propitious to produce the exopolysaccharide component of the matrix. When cells are grown under conditions that favor matrix production, the toxicity of galactose is relieved. This allowed us to demonstrate that galactose metabolism is essential for the synthesis of the extracellular matrix.

scholarly journals The Exo-Polysaccharide Component of Extracellular Matrix is Essential for the Viscoelastic Properties of Bacillus subtilis Biofilms

2020 ◽  
Vol 21 (18) ◽  
pp. 6755 ◽  
Author(s):  
Santosh Pandit ◽  
Mina Fazilati ◽  
Karolina Gaska ◽  
Abderahmane Derouiche ◽  
Tiina Nypelö ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Bacillus Subtilis ◽  
Mechanical Stress ◽  
Viscoelastic Properties ◽  
Mechanical Stability ◽  
Growth Dynamics ◽  
Interfacial Rheology ◽  
The Matrix ◽  
Infection Processes ◽  
Biofilm Matrix

Bacteria are known to form biofilms on various surfaces. Biofilms are multicellular aggregates, held together by an extracellular matrix, which is composed of biological polymers. Three principal components of the biofilm matrix are exopolysaccharides (EPS), proteins, and nucleic acids. The biofilm matrix is essential for biofilms to remain organized under mechanical stress. Thanks to their polymeric nature, biofilms exhibit both elastic and viscous mechanical characteristics; therefore, an accurate mechanical description needs to take into account their viscoelastic nature. Their viscoelastic properties, including during their growth dynamics, are crucial for biofilm survival in many environments, particularly during infection processes. How changes in the composition of the biofilm matrix affect viscoelasticity has not been thoroughly investigated. In this study, we used interfacial rheology to study the contribution of the EPS component of the matrix to viscoelasticity of Bacillus subtilis biofilms. Two strategies were used to specifically deplete the EPS component of the biofilm matrix, namely (i) treatment with sub-lethal doses of vitamin C and (ii) seamless inactivation of the eps operon responsible for biosynthesis of the EPS. In both cases, the obtained results suggest that the EPS component of the matrix is essential for maintaining the viscoelastic properties of bacterial biofilms during their growth. If the EPS component of the matrix is depleted, the mechanical stability of biofilms is compromised and the biofilms become more susceptible to eradication by mechanical stress.

scholarly journals KinD Is a Checkpoint Protein Linking Spore Formation to Extracellular-Matrix Production in Bacillus subtilis Biofilms

mBio ◽  
2010 ◽  
Vol 1 (1) ◽  
Author(s):  
Claudio Aguilar ◽  
Hera Vlamakis ◽  
Alejandra Guzman ◽  
Richard Losick ◽  
Roberto Kolter
Keyword(s):  
Extracellular Matrix ◽  
Bacillus Subtilis ◽  
Cell Types ◽  
Deficient Mutant ◽  
Content Type ◽  
Checkpoint Protein ◽  
Extracellular Matrix Production ◽  
The Matrix ◽  
Matrix Production ◽  
Low Levels

ABSTRACTBacillus subtiliscells form multicellular biofilm communities in which spatiotemporal regulation of gene expression occurs, leading to differentiation of multiple coexisting cell types. These cell types include matrix-producing and sporulating cells. Extracellular matrix production and sporulation are linked in that a mutant unable to produce matrix is delayed for sporulation. Here, we show that the delay in sporulation is not due to a growth advantage of the matrix-deficient mutant under these conditions. Instead, we show that the link between matrix production and sporulation is through the Spo0A signaling pathway. Both processes are regulated by the phosphorylated form of the master transcriptional regulator Spo0A. When cells have low levels of phosphorylated Spo0A (Spo0A~P), matrix genes are expressed; however, at higher levels of Spo0A~P, sporulation commences. We have found that Spo0A~P levels are maintained at low levels in the matrix-deficient mutant, thereby delaying expression of sporulation-specific genes. This is due to the activity of one of the components of the Spo0A phosphotransfer network, KinD. A deletion ofkinDsuppresses the sporulation defect of matrix mutants, while its overproduction delays sporulation. Our data indicate that KinD displays a dual role as a phosphatase or a kinase and that its activity is linked to the presence of extracellular matrix in the biofilms. We propose a novel role for KinD in biofilms as a checkpoint protein that regulates the onset of sporulation by inhibiting the activity of Spo0A until matrix, or a component therein, is sensed.IMPORTANCEA question in the field of biofilm development has remained virtually unaddressed: how do the biofilm cells sense the completion of the synthesis of extracellular matrix? The presence of an extracellular matrix that holds the cells together is a defining feature of biofilms. How cells sense that matrix has been assembled and how this signal is transduced have not been investigated.Bacillus subtilisprovides an excellent system in which to address this question, as the molecular pathways involved in regulation of differentiation are well characterized. We provide the first evidence for a protein that senses the presence of matrix. We identify a membrane sensor histidine kinase, KinD, that alters its activity, depending on the presence or absence of the extracellular matrix. This activity feeds back to the master regulator Spo0A to regulate expression of genes involved in producing matrix and genes necessary for the progression into sporulation.

scholarly journals Poly-gamma-glutamic acid secretion protects Bacillus subtilis from zinc and copper intoxication

2021 ◽  
Author(s):  
Reina Deol ◽  
Ashweetha Louis ◽  
Harper Lee Glazer ◽  
Warren Hosseinion ◽  
Pete Chandrangsu
Keyword(s):  
Bacillus Subtilis ◽  
Glutamic Acid ◽  
Regulatory System ◽  
Metal Resistance ◽  
Protective Mechanism ◽  
Transcriptional Level ◽  
Gram Positive ◽  
Diverse Range ◽  
Copper Excess ◽  
Copper Intoxication

AbstractZinc and copper are essential micronutrients that serve as a cofactors for numerous enzymes. However, when present at elevated concentrations, zinc and copper are highly toxic to bacteria. To combat the effects of zinc and copper excess, bacteria have evolved a wide array of defense mechanisms. Here, we show that the Gram positive soil bacterium, Bacillus subtilis, produces the extracellular polymeric substance, poly-gamma-glutamate (γ-PGA) as a protective mechanism in response to zinc and copper excess. Furthermore, we provide evidence that zinc and copper dependent γ-PGA production is independent of the DegS-DegQ two component regulatory system and likely occurs at a post-transcriptional level. These data provide new insight into bacterial metal resistance mechanisms and contribute to our understanding of the regulation of bacterial γ-PGA biosynthesis.ImportanceZinc and copper are potent antimicrobial compounds. As such, bacteria have evolved a diverse range of tools to prevent metal intoxication. Here, we show that the Gram-positive model organism, Bacillus subtilis, produces poly-gamma-glutamic acid (γ-PGA) as a protective mechanism against zinc and copper intoxication and that zinc and copper dependent γ-PGA production occurs by a yet undefined mechanism independent of known γ-PGA regulation pathways.

scholarly journals The Biocide Chlorine Dioxide Stimulates Biofilm Formation in Bacillus subtilis by Activation of the Histidine Kinase KinC

2010 ◽  
Vol 192 (24) ◽  
pp. 6352-6356 ◽  
Author(s):  
Moshe Shemesh ◽  
Roberto Kolter ◽  
Richard Losick
Keyword(s):  
Bacillus Subtilis ◽  
Chlorine Dioxide ◽  
Histidine Kinase ◽  
Biofilm Formation ◽  
Defensive Response ◽  
The Matrix ◽  
Membrane Bound ◽  
Sublethal Doses ◽  
Matrix Production ◽  
Fast Acting

ABSTRACT Bacillus subtilis forms biofilms in response to signals that remain poorly defined. We report that biofilm formation is stimulated by sublethal doses of chlorine dioxide (ClO2), an extremely effective and fast-acting biocide. ClO2 accelerated biofilm formation in B. subtilis as well as in other bacteria, suggesting that biofilm formation is a widely conserved response to sublethal doses of the agent. Biofilm formation depends on the synthesis of an extracellular matrix that holds the constituent cells together. We show that the transcription of the major operons responsible for the matrix production in B. subtilis, epsA-epsO and yqxM-sipW-tasA, was enhanced by ClO2, in a manner that depended on the membrane-bound kinase KinC. Activation of KinC appeared to be due to the ability of ClO2 to collapse the membrane potential. Importantly, strains unable to make a matrix were hypersensitive to ClO2, indicating that biofilm formation is a defensive response that helps protect cells from the toxic effects of the biocide.

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