scholarly journals ResDE Two-Component Regulatory System Mediates Oxygen Limitation-Induced Biofilm Formation byBacillus amyloliquefaciensSQR9

2018 ◽  
Vol 84 (8) ◽  
pp. e02744-17 ◽  
Author(s):  
Xuan Zhou ◽  
Nan Zhang ◽  
Liming Xia ◽  
Qing Li ◽  
Jiahui Shao ◽  
...  
Keyword(s):  
Plant Growth ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Oxygen Deficiency ◽  
Regulatory System ◽  
Regulatory Function ◽  
Content Type ◽  
Environmental Signals ◽  
Link Type ◽  
Two Component

ABSTRACTEfficient biofilm formation and root colonization capabilities facilitate the ability of beneficial plant rhizobacteria to promote plant growth and antagonize soilborne pathogens. Biofilm formation by plant-beneficialBacillusstrains is triggered by environmental cues, including oxygen deficiency, but the pathways that sense these environmental signals and regulate biofilm formation have not been thoroughly elucidated. In this study, we showed that the ResDE two-component regulatory system in the plant growth-promoting rhizobacteriumBacillus amyloliquefaciensstrain SQR9 senses the oxygen deficiency signal and regulates biofilm formation. ResE is activated by sensing the oxygen limitation-induced reduction of the NAD+/NADH pool through its PAS domain, stimulating its kinase activity, and resulting in the transfer of a phosphoryl group to ResD. The phosphorylated ResD directly binds to the promoter regions of theqoxABCDandctaCDEFoperons to improve the biosynthesis of terminal oxidases, which can interact with KinB to activate biofilm formation. These results not only revealed the novel regulatory function of the ResDE two-component system but also contributed to the understanding of the complicated regulatory network governingBacillusbiofilm formation. This research may help to enhance the root colonization and the plant-beneficial efficiency of SQR9 and otherBacillusrhizobacteria used in agriculture.IMPORTANCEBacillusspp. are widely used as bioinoculants for plant growth promotion and disease suppression. The exertion of their plant-beneficial functions is largely dependent on their root colonization, which is closely related to their biofilm formation capabilities. On the other hand,Bacillusis the model bacterium for biofilm study, and the process and molecular network of biofilm formation are well characterized (B. Mielich-Süss and D. Lopez, Environ Microbiol 17:555–565, 2015,https://doi.org/10.1111/1462-2920.12527; L. S. Cairns, L. Hobley, and N. R. Stanley-Wall, Mol Microbiol 93:587–598, 2014,https://doi.org/10.1111/mmi.12697; H. Vlamakis, C. Aguilar, R. Losick, and R. Kolter, Genes Dev 22:945–953, 2008,https://doi.org/10.1101/gad.1645008; S. S. Branda, A. Vik, L. Friedman, and R. Kolter, Trends Microbiol 13:20–26, 2005,https://doi.org/10.1016/j.tim.2004.11.006; C. Aguilar, H. Vlamakis, R. Losick, and R. Kolter, Curr Opin Microbiol 10:638–643, 2007,https://doi.org/10.1016/j.mib.2007.09.006; S. S. Branda, J. E. González-Pastor, S. Ben-Yehuda, R. Losick, and R. Kolter, Proc Natl Acad Sci U S A 98:11621–11626, 2001,https://doi.org/10.1073/pnas.191384198). However, the identification and sensing of environmental signals triggeringBacillusbiofilm formation need further research. Here, we report that the oxygen deficiency signal inducingBacillusbiofilm formation is sensed by the ResDE two-component regulatory system. Our results not only revealed the novel regulatory function of the ResDE two-component regulatory system but also identified the sensing system of a biofilm-triggering signal. This knowledge can help to enhance the biofilm formation and root colonization of plant-beneficialBacillusstrains and also provide new insights of bacterial biofilm formation regulation.

scholarly journals Bacillus velezensisWall Teichoic Acids Are Required for Biofilm Formation and Root Colonization

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Zhihui Xu ◽  
Huihui Zhang ◽  
Xinli Sun ◽  
Yan Liu ◽  
Wuxia Yan ◽  
...  
Keyword(s):  
Plant Growth ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Molecular Networks ◽  
Model Organisms ◽  
Bacillus Velezensis ◽  
Content Type ◽  
Plant Growth Promoting ◽  
Colonization Process ◽  
Growth Promoting

ABSTRACTRhizosphere colonization by plant growth-promoting rhizobacteria (PGPR) along plant roots facilitates the ability of PGPR to promote plant growth and health. Thus, an understanding of the molecular mechanisms of the root colonization process by plant-beneficialBacillusstrains is essential for the use of these strains in agriculture. Here, we observed that ansfpgene mutant of the plant growth-promoting rhizobacteriumBacillus velezensisSQR9 was unable to form normal biofilm architecture, and differential protein expression was observed by proteomic analysis. A minor wall teichoic acid (WTA) biosynthetic protein, GgaA, was decreased over 4-fold in the Δsfpmutant, and impairment of theggaAgene postponed biofilm formation and decreased cucumber root colonization capabilities. In addition, we provide evidence that the major WTA biosynthetic enzyme GtaB is involved in both biofilm formation and root colonization. The deficiency in biofilm formation of the ΔgtaBmutant may be due to an absence of UDP-glucose, which is necessary for the synthesis of biofilm matrix exopolysaccharides (EPS). These observations provide insights into the root colonization process by a plant-beneficialBacillusstrain, which will help improve its application as a biofertilizer.IMPORTANCEBacillus velezensisis a Gram-positive plant-beneficial bacterium which is widely used in agriculture. Additionally,Bacillusspp. are some of the model organisms used in the study of biofilms, and as such, the molecular networks and regulation systems of biofilm formation are well characterized. However, the molecular processes involved in root colonization by plant-beneficialBacillusstrains remain largely unknown. Here, we showed that WTAs play important roles in the plant root colonization process. The loss of thegtaBgene affects the ability ofB. velezensisSQR9 to sense plant polysaccharides, which are important environmental cues that trigger biofilm formation and colonization in the rhizosphere. This knowledge provides new insights into theBacillusroot colonization process and can help improve our understanding of plant-rhizobacterium interactions.

scholarly journals Polymyxin B Resistance and Biofilm Formation in Vibrio cholerae Are Controlled by the Response Regulator CarR

2015 ◽  
Vol 83 (3) ◽  
pp. 1199-1209 ◽  
Author(s):  
Kivanc Bilecen ◽  
Jiunn C. N. Fong ◽  
Andrew Cheng ◽  
Christopher J. Jones ◽  
David Zamorano-Sánchez ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Lipid A ◽  
Response Regulator ◽  
Regulatory Region ◽  
Regulatory System ◽  
Polymyxin B ◽  
Content Type ◽  
Two Component ◽  
Antimicrobial Peptide Resistance

Two-component systems play important roles in the physiology of many bacterial pathogens.Vibrio cholerae's CarRS two-component regulatory system negatively regulates expression ofvps(Vibriopolysaccharide) genes and biofilm formation. In this study, we report that CarR confers polymyxin B resistance by positively regulating expression of thealmEFGgenes, whose products are required for glycine and diglycine modification of lipid A. We determined that CarR directly binds to the regulatory region of thealmEFGoperon. Similarly to acarRmutant, strains lackingalmE,almF, andalmGexhibited enhanced polymyxin B sensitivity. We also observed that strains lackingalmEor thealmEFGoperon have enhanced biofilm formation. Our results reveal that CarR regulates biofilm formation and antimicrobial peptide resistance inV. cholerae.

scholarly journals The Vancomycin Resistance-Associated Regulatory System VraSR Modulates Biofilm Formation of Staphylococcus epidermidis in an ica -Dependent Manner

mSphere ◽  
2021 ◽  
Author(s):  
Youcong Wu ◽  
Yuanyuan Meng ◽  
Lian Qian ◽  
Baixing Ding ◽  
Haiyan Han ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Regulatory System ◽  
Vancomycin Resistance ◽  
Dependent Manner ◽  
Content Type ◽  
Two Component ◽  
Complex Procedure ◽  
Hospital Acquired

S. epidermidis is a leading cause of hospital-acquired catheter-related infections, and its pathogenicity depends mostly on its ability to form biofilms on implants. The biofilm formation is a complex procedure that involves multiple regulating factors. Here, we show that a vancomycin resistance-associated two-component regulatory system, VraSR, plays an important role in modulating S. epidermidis biofilm formation and tolerance to stress.

scholarly journals An Osmoregulatory Mechanism Operating through OmpR and LrhA Controls the Motile-Sessile Switch in the Plant Growth-Promoting BacteriumPantoea alhagi

2019 ◽  
Vol 85 (10) ◽  
Author(s):  
Shuyu Li ◽  
Hong Liang ◽  
Zhiyan Wei ◽  
Haonan Bai ◽  
Mengyun Li ◽  
...  
Keyword(s):  
Plant Growth ◽  
Osmotic Stress ◽  
Biofilm Formation ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Osmoregulatory Mechanism

ABSTRACTAdaptation to osmotic stress is crucial for bacterial growth and survival in changing environments. Although a large number of osmotic stress response genes have been identified in various bacterial species, how osmotic changes affect bacterial motility, biofilm formation, and colonization of host niches remains largely unknown. In this study, we report that the LrhA regulator is an osmoregulated transcription factor that directly binds to the promoters of theflhDC,eps, andopgGHoperons and differentially regulates their expression, thus inhibiting motility and promoting exopolysaccharide (EPS) production, synthesis of osmoregulated periplasmic glucans (OPGs), biofilm formation, and root colonization of the plant growth-promoting bacteriumPantoea alhagiLTYR-11Z. Further, we observed that the LrhA-regulated OPGs control RcsCD-RcsB activation in a concentration-dependent manner, and a high concentration of OPGs induced by increased medium osmolarity is maintained to achieve the high level of activation of the Rcs phosphorelay, which results in enhanced EPS synthesis and decreased motility inP. alhagi. Moreover, we showed that the osmosensing regulator OmpR directly binds to the promoter oflrhAand promotes its expression, whilelrhAexpression is feedback inhibited by the activated Rcs phosphorelay system. Overall, our data support a model wherebyP. alhagisenses environmental osmolarity changes through the EnvZ-OmpR two-component system and LrhA to regulate the synthesis of OPGs, EPS production, and flagellum-dependent motility, thereby employing a hierarchical signaling cascade to control the transition between a motile lifestyle and a biofilm lifestyle.IMPORTANCEMany motile bacterial populations form surface-attached biofilms in response to specific environmental cues, including osmotic stress in a range of natural and host-related systems. However, cross talk between bacterial osmosensing, swimming, and biofilm formation regulatory networks is not fully understood. Here, we report that the pleiotropic regulator LrhA inPantoea alhagiis involved in the regulation of flagellar motility, biofilm formation, and host colonization and responds to osmotic upshift. We further show that this sensing relies on the EnvZ-OmpR two-component system that was known to detect changes in external osmotic stress. The EnvZ-OmpR-LrhA osmosensing signal transduction cascade is proposed to increase bacterial fitness under hyperosmotic conditions inside the host. Our work proposes a novel regulatory mechanism that links osmosensing and motile-sessile lifestyle transitions, which may provide new approaches to prevent or promote the formation of biofilms and host colonization inP. alhagiand other bacteria possessing a similar osmoregulatory mechanism.

scholarly journals Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems

2020 ◽  
Vol 69 (6) ◽  
pp. 906-919 ◽  
Author(s):  
Divakar Badal ◽  
Abhijith Vimal Jayarani ◽  
Mohammed Ameen Kollaran ◽  
Aloke Kumar ◽  
Varsha Singh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Type Species ◽  
Content Type ◽  
Endotracheal Tubes ◽  
Link Type ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator. Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process. Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility. Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility. Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.

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.

The role of Akkermansia muciniphila in obesity, diabetes and atherosclerosis

2021 ◽  
Vol 70 (10) ◽  
Author(s):  
Alka Hasani ◽  
Saba Ebrahimzadeh ◽  
Fatemeh Hemmati ◽  
Aytak Khabbaz ◽  
Akbar Hasani ◽  
...  
Keyword(s):  
Type Species ◽  
Anaerobic Bacteria ◽  
Regulatory System ◽  
Content Type ◽  
Akkermansia Muciniphila ◽  
Link Type ◽  
Animal Trials ◽  
Obesity And Diabetes ◽  
Underlying Mechanisms

Alteration in the composition of the gut microbiota can lead to a number of chronic clinical diseases. Akkermansia muciniphila is an anaerobic bacteria constituting 3–5% of the gut microbial community in healthy adults. This bacterium is responsible for degenerating mucin in the gut; its scarcity leads to diverse clinical disorders. In this review, we focus on the role of A. muciniphila in diabetes, obesity and atherosclerosis, as well as the use of this bacterium as a next-generation probiotic. In regard to obesity and diabetes, human and animal trials have shown that A. muciniphila controls the essential regulatory system of glucose and energy metabolism. However, the underlying mechanisms by which A. muciniphila alleviates the complications of obesity, diabetes and atherosclerosis are unclear. At the same time, its abundance suggests improved metabolic disorders, such as metabolic endotoxemia, adiposity insulin resistance and glucose tolerance. The role of A. muciniphila is implicated in declining aortic lesions and atherosclerosis. Well-characterized virulence factors, antigens and cell wall extracts of A. muciniphila may act as effector molecules in these diseases. These molecules may provide novel mechanisms and strategies by which this bacterium could be used as a probiotic for the treatment of obesity, diabetes and atherosclerosis.

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.

scholarly journals Identification of a Second Two-Component Signal Transduction System That Controls Fosfomycin Tolerance and Glycerol-3-Phosphate Uptake

2014 ◽  
Vol 197 (5) ◽  
pp. 861-871 ◽  
Author(s):  
Kumiko Kurabayashi ◽  
Yuko Hirakawa ◽  
Koichi Tanimoto ◽  
Haruyoshi Tomita ◽  
Hidetada Hirakawa
Keyword(s):  
Phosphate Uptake ◽  
Response Regulator ◽  
Anaerobic Respiration ◽  
Regulatory System ◽  
Carbon Substrate ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Biological Cost

Particular interest in fosfomycin has resurfaced because it is a highly beneficial antibiotic for the treatment of refractory infectious diseases caused by pathogens that are resistant to other commonly used antibiotics. The biological cost to cells of resistance to fosfomycin because of chromosomal mutation is high. We previously found that a bacterial two-component system, CpxAR, induces fosfomycin tolerance in enterohemorrhagicEscherichia coli(EHEC) O157:H7. This mechanism does not rely on irreversible genetic modification and allows EHEC to relieve the fitness burden that results from fosfomycin resistance in the absence of fosfomycin. Here we show that another two-component system, TorSRT, which was originally characterized as a regulatory system for anaerobic respiration utilizing trimethylamine-N-oxide (TMAO), also induces fosfomycin tolerance. Activation of the Tor regulatory pathway by overexpression oftorR, which encodes the response regulator, or addition of TMAO increased fosfomycin tolerance in EHEC. We also show that phosphorylated TorR directly represses the expression ofglpT, a gene that encodes a symporter of fosfomycin and glycerol-3-phosphate, and activation of the TorR protein results in the reduced uptake of fosfomycin by cells. However, cells in which the Tor pathway was activated had an impaired growth phenotype when cultured with glycerol-3-phosphate as a carbon substrate. These observations suggest that the TorSRT pathway is the second two-component system to reversibly control fosfomycin tolerance and glycerol-3-phosphate uptake in EHEC, and this may be beneficial for bacteria by alleviating the biological cost. We expect that this mechanism could be a potential target to enhance the utility of fosfomycin as chemotherapy against multidrug-resistant pathogens.

scholarly journals Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Reed M. Stubbendieck ◽  
Paul D. Straight
Keyword(s):  
Antibiotic Resistance ◽  
Abc Transporter ◽  
Bacterial Communities ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bioactive Metabolites ◽  
Signaling System ◽  
Content Type ◽  
Two Component ◽  
Analytical Approaches

ABSTRACT Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilis. IMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.

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