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 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 Host factors abolish the need for polysaccharides and extracellular matrix-binding protein in Staphylococcus epidermidis biofilm formation

2021 ◽  
Author(s):  
Sandra M. Skovdal ◽  
Liva Kjær Hansen ◽  
Diana Malskær Ivarsen ◽  
Guanghong Zeng ◽  
Henning Büttner ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Human Plasma ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Type Species ◽  
Host Factors ◽  
Content Type ◽  
Link Type ◽  
Matrix Components

Introduction. Staphylococcus epidermidis is predominant in implant-associated infections due to its capability to form biofilms. It can deploy several strategies for biofilm development using either polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA) and/or proteins, such as the extracellular matrix-binding protein (Embp). Hypothesis/Gap Statement. We hypothesize that the dichotomic regulation of S. epidermidis adhesins is linked to whether it is inside a host or not, and that in vitro biofilm investigations in laboratory media may not reflect actual biofilms in vivo. Aim. We address the importance of PIA and Embp in biofilm grown in ‘humanized’ media to understand if these components play different roles in biofilm formation under conditions where bacteria can incorporate host proteins in the biofilm matrix. Methodology. S. epidermidis 1585 WT (deficient in icaADBC), and derivative strains that either lack embp, express embp from an inducible promotor, or express icaADBC from a plasmid, were cultivated in standard laboratory media, or in media with human plasma or serum. The amount, structure, elasticity and antimicrobial penetration of biofilms was quantified to describe structural differences caused by the different matrix components and growth conditions. Finally, we quantified the initiation of biofilms as suspended aggregates in response to host factors to determine how quickly the cells aggregate in response to the host environment and reach a size that protects them from phagocytosis. Results. S. epidermidis 1585 required polysaccharides to form biofilm in laboratory media. However, these observations were not representative of the biofilm phenotype in the presence of human plasma. If human plasma were present, polysaccharides and Embp were redundant for biofilm formation. Biofilms formed in human plasma were loosely attached and existed mostly as suspended aggregates. Aggregation occurred after 2 h of exposing cells to plasma or serum. Despite stark differences in the amount and composition of biofilms formed by polysaccharide-producing and Embp-producing strains in different media, there were no differences in vancomycin penetration or susceptibility. Conclusion. We suggest that the assumed importance of polysaccharides for biofilm formation is an artefact from studying biofilms in laboratory media void of human matrix components. The cell–cell aggregation of S. epidermidis can be activated by host factors without relying on either of the major adhesins, PIA and Embp, indicating a need to revisit the basic question of how S. epidermidis deploys self-produced and host-derived matrix components to form antibiotic-tolerant biofilms in vivo.

scholarly journals Biofilm formation by Bacillus subtilis is altered in the presence of pesticides

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Rachael Newton ◽  
Jennifer Amstutz ◽  
Joyce E. Patrick
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Type Species ◽  
Symbiotic Relationship ◽  
Neem Oil ◽  
Swarming Motility ◽  
Content Type ◽  
Future Studies ◽  
Link Type

Bacillus subtilis uses swarming motility and biofilm formation to colonize plant roots and form a symbiotic relationship with the plant. Swarming motility and biofilm formation are group behaviours made possible through the use of chemical messengers. We investigated whether chemicals applied to plants would interfere with the swarming motility and biofilm-forming capabilities of B. subtilis in vitro. We hypothesized that pesticides could act as chemical signals that influence bacterial behaviour; this research investigates whether swarming motility and biofilm formation of B. subtilis is affected by the application of the commercial pesticides with the active ingredients of neem oil, pyrethrin, or malathion. The results indicate that all three pesticides inhibit biofilm formation. Swarming motility is not affected by the application of pyrethrin or malathion, but swarm expansion and pattern is altered in the presence of neem oil. Future studies to investigate the mechanism by which pesticides alter biofilm formation are warranted.

Two regulatory factors of Vibrio cholerae activating the mannose-sensitive haemagglutinin pilus expression is important for biofilm formation and colonization in mice

Microbiology ◽  
2021 ◽  
Vol 167 (10) ◽  
Author(s):  
Mengting Shi ◽  
Yue Zheng ◽  
Xianghong Wang ◽  
Zhengjia Wang ◽  
Menghua Yang
Keyword(s):  
Mouse Model ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Type Species ◽  
Wild Type ◽  
Expression Library ◽  
Content Type ◽  
Genomic Expression ◽  
Infant Mouse ◽  
Link Type

Vibrio cholerae the causative agent of cholera, uses a large number of coordinated transcriptional regulatory events to transition from its environmental reservoir to the host intestine, which is its preferred colonization site. Transcription of the mannose-sensitive haemagglutinin pilus (MSHA), which aids the persistence of V. cholerae in aquatic environments, but causes its clearance by host immune defenses, was found to be regulated by a yet unknown mechanism during the infection cycle of V. cholerae . In this study, genomic expression library screening revealed that two regulators, VC1371 and VcRfaH, are able to positively activate the transcription of MSHA operon. VC1371 is localized and active in the cell membrane. Deletion of vc1371 or VcrfaH genes in V. cholerae resulted in less MshA protein production and less efficiency of biofilm formation compared to that in the wild-type strain. An adult mouse model showed that the mutants with vc1371 or VcrfaH deletion colonized less efficiently than the wild-type; the VcrfaH deletion mutant showed less colonization efficiency in the infant mouse model. The findings strongly suggested that the two regulators, namely VC1371 and VcRfaH, which are involved in the regulation of MSHA expression, play an important role in V. cholerae biofilm formation and colonization in mice.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

Environment in the lung of cystic fibrosis patients stimulates the expression of biofilm phenotype in Mycobacterium abscessus

2022 ◽  
Vol 71 (1) ◽  
Author(s):  
Bailey F. Keefe ◽  
Luiz E. Bermudez
Keyword(s):  
Cystic Fibrosis ◽  
Host Cell ◽  
Biofilm Formation ◽  
Type Species ◽  
Divalent Cations ◽  
Mycobacterium Abscessus ◽  
Content Type ◽  
Link Type ◽  
Populations At Risk

Introduction. Pulmonary infections caused by organisms of the Mycobacterium abscessus complex are increasingly prevalent in populations at risk, such as patients with cystic fibrosis, bronchiectasis and emphysema. Hypothesis. M. abscessus infection of the lung is not observed in immunocompetent individuals, which raises the possibility that the compromised lung environment is a suitable niche for the pathogen to thrive in due to the overproduction of mucus and high amounts of host cell lysis. Aim. Evaluate the ability of M. abscessus to form biofilm and grow utilizing in vitro conditions as seen in immunocompromised lungs of patients. Methodology. We compared biofilm formation and protein composition in the presence and absence of synthetic cystic fibrosis medium (SCFM) and evaluated the bacterial growth when exposed to human DNA. Results. M. abscessus is capable of forming biofilm in SCFM. By eliminating single components found in the medium, it became clear that magnesium works as a signal for the biofilm formation, and chelation of the divalent cations resulted in the suppression of biofilm formation. Investigation of the specific proteins expressed in the presence of SCFM and in the presence of SCFM lacking magnesium revealed many different proteins between the conditions. M. abscessus also exhibited growth in SCFM and in the presence of host cell DNA, although the mechanism of DNA utilization remains unclear. Conclusions. In vitro conditions mimicking the airways of patients with cystic fibrosis appear to facilitate M. abscessus establishment of infection, and elimination of magnesium from the environment may affect the ability of the pathogen to establish infection.

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 Catabolite Repressor Protein-Cyclic AMP Complex RegulatescsgDand Biofilm Formation in Uropathogenic Escherichia coli

2016 ◽  
Vol 198 (24) ◽  
pp. 3329-3334 ◽  
Author(s):  
David A. Hufnagel ◽  
Margery L. Evans ◽  
Sarah E. Greene ◽  
Jerome S. Pinkner ◽  
Scott J. Hultgren ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Extracellular Matrix ◽  
Cyclic Amp ◽  
Intergenic Region ◽  
Biofilm Formation ◽  
Cellulose Production ◽  
Content Type ◽  
E Coli ◽  
Link Type ◽  
K1 Capsule

ABSTRACTThe extracellular matrix protectsEscherichia colifrom immune cells, oxidative stress, predation, and other environmental stresses. Production of theE. coliextracellular matrix is regulated by transcription factors that are tuned to environmental conditions. The biofilm master regulator protein CsgD upregulates curli and cellulose, the two major polymers in the extracellular matrix of uropathogenicE. coli(UPEC) biofilms. We found that cyclic AMP (cAMP) regulates curli, cellulose, and UPEC biofilms throughcsgD. The alarmone cAMP is produced by adenylate cyclase (CyaA), and deletion ofcyaAresulted in reduced extracellular matrix production and biofilm formation. Thecataboliterepressorprotein (CRP) positively regulatedcsgDtranscription, leading to curli and cellulose production in the UPEC isolate, UTI89. Glucose, a known inhibitor of CyaA activity, blocked extracellular matrix formation when added to the growth medium. The mutant strains ΔcyaAand Δcrpdid not produce rugose biofilms, pellicles, curli, cellulose, or CsgD. Three putative CRP binding sites were identified within thecsgD-csgBintergenic region, and purified CRP could gel shift thecsgD-csgBintergenic region. Additionally, we found that CRP binded upstream ofkpsMT, which encodes machinery for K1 capsule production. Together our work shows that cAMP and CRP influenceE. colibiofilms through transcriptional regulation ofcsgD.IMPORTANCEThecataboliterepressorprotein (CRP)-cyclic AMP (cAMP) complex influences the transcription of ∼7% of genes on theEscherichia colichromosome (D. Zheng, C. Constantinidou, J. L. Hobman, and S. D. Minchin, Nucleic Acids Res 32:5874–5893, 2004,https://dx.doi.org/10.1093/nar/gkh908). Glucose inhibitsE. colibiofilm formation, and ΔcyaAand Δcrpmutants show impaired biofilm formation (D. W. Jackson, J.W. Simecka, and T. Romeo, J Bacteriol 184:3406–3410, 2002,https://dx.doi.org/10.1128/JB.184.12.3406-3410.2002). We determined that the cAMP-CRP complex regulates curli and cellulose production and the formation of rugose and pellicle biofilms throughcsgD. Additionally, we propose that cAMP may work as a signaling compound for uropathogenicE. coli(UPEC) to transition from the bladder lumen to inside epithelial cells for intracellular bacterial community formation through K1 capsule regulation.

scholarly journals Study of quorum-sensing LasR and RhlR genes and their dependent virulence factors in Pseudomonas aeruginosa isolates from infected burn wounds

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Aya Ahmad Elnegery ◽  
Wafaa Kamel Mowafy ◽  
Tarek Ahmed Zahra ◽  
Noha Tharwat Abou El-Khier
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Proteolytic Activity ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Type Species ◽  
Assay Method ◽  
Content Type ◽  
Burn Wounds ◽  
Link Type

Background. Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen responsible for burn-wound infection. High incidence, infection severity and increasing resistance characterize P. aeruginosa -induced burn infection. Purpose. To estimate quorum-sensing (QS)-dependent virulence factors of P. aeruginosa isolates from burn wounds and correlate it to the presence of QS genes. Methods. A cross-sectional descriptive study included 50 P . aeruginosa isolates from burn patients in Mansoura University Plastic and Burn Hospital, Egypt. Antibiotic sensitivity tests were done. All isolates were tested for their ability to produce biofilm using a micro-titration assay method. Protease, pyocyanin and rhamnolipid virulence factors were determined using skimmed milk agar, King’s A medium and CTAB agar test, respectively. The identity of QS lasR and rhlR genes was confirmed using PCR. Results. In total, 86 % of isolates had proteolytic activity. Production of pyocyanin pigment was manifested in 66 % of isolates. Altogether, 76 % of isolates were rhamnolipid producers. Biofilm formation was detected in 96 % of isolates. QS lasR and rhlR genes were harboured by nearly all isolates except three isolates were negative for both lasR and rhlR genes and two isolates were positive for lasR gene and negative for rhlR gene. Forty-nine isolates were considered as extremely QS-proficient strains as they produced QS-dependent virulence factors. In contrast, one isolate was a QS deficient strain. Conclusions. QS affects P. aeruginosa virulence-factor production and biofilm in burn wounds. Isolates containing lasR and rhlR seem to be a crucial regulator of virulence factors and biofilm formation in P. aeruginosa whereas the lasR gene positively regulates biofilm formation, proteolytic activity, pyocyanin production and rhamnolipid biosurfactant synthesis. The QS regulatory RhlR gene affects protease and rhamnolipid production positively.

scholarly journals Reclassification of the biocontrol agents Bacillus subtilis BY-2 and Tu-100 as Bacillus velezensis and insights into the genomic and specialized metabolite diversity of the species

Microbiology ◽  
2020 ◽  
Vol 166 (12) ◽  
pp. 1121-1128 ◽  
Author(s):  
Alex J. Mullins ◽  
Yinshui Li ◽  
Lu Qin ◽  
Xiaojia Hu ◽  
Lihua Xie ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Natural Product ◽  
Type Species ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Core Gene ◽  
Biocontrol Agents ◽  
Bacillus Velezensis ◽  
Content Type ◽  
Link Type

The genomes of two historical Bacillus species strains isolated from the roots of oilseed rape and used routinely in PR China as biocontrol agents to suppress Sclerotinia disease were sequenced. Average nucleotide identity (ANI) and digital DNA–DNA hybridization analyses demonstrated that they were originally misclassified as Bacillus subtilis and now belong to the bacterial species Bacillus velezensis . A broader ANI analysis of available Bacillus genomes identified 292 B. velezensis genomes that were then subjected to core gene analysis and phylogenomics. Prediction and dereplication of specialized metabolite biosynthetic gene clusters (BGCs) defined the prevalence of multiple antimicrobial-associated BGCs and highlighted the natural product potential of B. velezensis . By defining the core and accessory antimicrobial biosynthetic capacity of the species, we offer an in-depth understanding of B. velezensis natural product capacity to facilitate the selection and testing of B. velezensis strains for use as biological control agents.

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