Quorum sensing signal autoinducer-2 promotes root colonization of Bacillus velezensis SQR9 by affecting biofilm formation and motility

2020 ◽  
Vol 104 (16) ◽  
pp. 7177-7185
Author(s):  
Qin Xiong ◽  
Di Liu ◽  
Huihui Zhang ◽  
Xiaoyan Dong ◽  
Guishan Zhang ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Bacillus Velezensis ◽  
Autoinducer 2

scholarly journals Autoinducer-2 Triggers the Oxidative Stress Response in Mycobacterium avium, Leading to Biofilm Formation

2008 ◽  
Vol 74 (6) ◽  
pp. 1798-1804 ◽  
Author(s):  
Henriette Geier ◽  
Serge Mostowy ◽  
Gerard A. Cangelosi ◽  
Marcel A. Behr ◽  
Timothy E. Ford
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Quorum Sensing ◽  
Mycobacterium Avium ◽  
Biofilm Formation ◽  
Transcriptional Response ◽  
Opportunistic Pathogen ◽  
Environmental Stresses ◽  
Oxidative Stress Response ◽  
Autoinducer 2

ABSTRACT Mycobacterium avium is an environmental organism and opportunistic pathogen with inherent resistance to drugs, environmental stresses, and the host immune response. To adapt to these disparate conditions, M. avium must control its transcriptional response to environmental cues. M. avium forms biofilms in various environmental settings, including drinking water pipes and potable water reservoirs. In this study, we investigated the role of the universal signaling molecule autoinducer-2 (AI-2) in biofilm formation by M. avium. The addition of the compound to planktonic M. avium cultures resulted in increased biofilm formation. Microarray and reverse transcriptase PCR studies revealed an upregulation of the oxidative stress response upon addition of AI-2. This suggests that the response to AI-2 might be related to oxidative stress, rather than quorum sensing. Consistent with this model, addition of hydrogen peroxide, a known stimulus of the oxidative stress response, to M. avium cultures resulted in elevated biofilm formation. These results suggest that AI-2 does not act as a quorum-sensing signal in M. avium. Instead, biofilm formation is triggered by environmental stresses of biotic and abiotic origins and AI-2 may exert effects on that level.

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.

Effect of interspecies quorum sensing on the formation of aerobic granular sludge

2011 ◽  
Vol 64 (6) ◽  
pp. 1284-1290 ◽  
Author(s):  
Sheng-Hua Zhang ◽  
Xin Yu ◽  
Feng Guo ◽  
Zhuo-ying Wu
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Essential Element ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Signal Molecules ◽  
Small Signal ◽  
Autoinducer 2

Quorum sensing (QS) is a form of microbial communication that relies on small signal molecules to regulate group behaviors such as biofilm formation in response to population density. In this study, we attempted to apply the paradigm of bacterial QS to aerobic granular sludge (AGS) formation for wastewater treatment. An essential element of interspecies QS signals, boron, was added to a sequencing batch reactor (SBR) to stimulate AGS growth. Bioassays elaborated the activity of autoinducer-2 (AI-2). We found that boron accelerated AGS growth, resulting in improved settlement performance and increased biomass in the SBR. During continuous SBR operation, the AGS showed an obvious increase in AI-2 activity, which implies that interspecies QS was closely associated with AGS formation. Analysis of EPS showed that boron stimulated tryptophan production, and increased the hydrophobia of AGS. From these results, it was speculated that the addition of boron may have promoted the formation of boron complexed to (R)-4, 5-dihydroxy-2,3-pentanedione (DPD) as the precursor of AI-2, which resulted in accelerated interspecies QS. The results also suggested QS as a novel regulation target for the biogranulation process, such as AGS formation.

scholarly journals Role of the luxS Quorum-Sensing System in Biofilm Formation and Virulence of Staphylococcus epidermidis

2006 ◽  
Vol 74 (1) ◽  
pp. 488-496 ◽  
Author(s):  
Lin Xu ◽  
Hualin Li ◽  
Cuong Vuong ◽  
Viveka Vadyvaloo ◽  
Jianping Wang ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Mutant Strain ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Pathogens ◽  
Sensing System ◽  
Autoinducer 2 ◽  
Enhanced Production ◽  
Quorum Sensing System ◽  
Biofilm Development

ABSTRACT Nosocomial infections caused by Staphylococcus epidermidis are characterized by biofilm formation on implanted medical devices. Quorum-sensing regulation plays a major role in the biofilm development of many bacterial pathogens. Here, we describe luxS, a quorum-sensing system in staphylococci that has a significant impact on biofilm development and virulence. We constructed an isogenic ΔluxS mutant strain of a biofilm-forming clinical isolate of S. epidermidis and demonstrated that luxS signaling is functional in S. epidermidis. The mutant strain showed increased biofilm formation in vitro and enhanced virulence in a rat model of biofilm-associated infection. Genetic complementation and addition of autoinducer 2-containing culture filtrate restored the wild-type phenotype, demonstrating that luxS repressed biofilm formation through a cell-cell signaling mechanism based on autoinducer 2 secretion. Enhanced production of the biofilm exopolysaccharide polysaccharide intercellular adhesin in the mutant strain is presumably the major cause of the observed phenotype. The agr quorum-sensing system has previously been shown to impact biofilm development and biofilm-associated infection in a way similar to that of luxS, although by regulation of different factors. Our study indicates a general scheme of quorum-sensing regulation of biofilm development in staphylococci, which contrasts with that observed in many other bacterial pathogens.

scholarly journals Inhibition of AI-2 Quorum Sensing and Biofilm Formation in Campylobacter jejuni by Decanoic and Lauric Acids

2022 ◽  
Vol 12 ◽  
Author(s):  
Shenmiao Li ◽  
Kelvin Ka-wan Chan ◽  
Marti Z. Hua ◽  
Greta Gölz ◽  
Xiaonan Lu
Keyword(s):  
Fatty Acids ◽  
Quorum Sensing ◽  
Campylobacter Jejuni ◽  
Lauric Acid ◽  
Biofilm Formation ◽  
Control Strategies ◽  
Decanoic Acid ◽  
Poultry Production ◽  
Bacterial Inactivation ◽  
Autoinducer 2

Campylobacter jejuni is a major bacterial cause of human diarrheal diseases worldwide. Despite its sensitivity to environmental stresses, C. jejuni ubiquitously distributes throughout poultry production chains. Biofilm formation mediated by quorum sensing is suggested to be critical to the survival of C. jejuni in agroecosystem. C. jejuni possesses LuxS, the enzyme involved in the production of autoinducer-2 (AI-2) signaling molecules. In this study, two fatty acids, namely decanoic acid and lauric acid, were identified to be effective in inhibiting AI-2 activity of C. jejuni. Both decanoic acid and lauric acid at 100 ppm inhibited ∼90% AI-2 activity (P < 0.05) of C. jejuni without bacterial inactivation. The biofilm biomass of two C. jejuni strains was reduced by 10–50% (P < 0.05) after treatment by both fatty acids, while increased biofilm formation was observed for one C. jejuni strain. In addition, both fatty acids effectively reduced the motility of all tested C. jejuni strains. These findings can aid in developing alternative C. jejuni control strategies in agri-food and clinical settings.

scholarly journals The role of luxS in Histophilus somni virulence and biofilm formation

2020 ◽  
Author(s):  
Yu Pan ◽  
Shivakumara Siddaramappa ◽  
Indra Sandal ◽  
Allan Dickerman ◽  
Aloka B. Bandara ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Phenotypic Properties ◽  
Autoinducer 2 ◽  
Histophilus Somni ◽  
Signalling Molecule ◽  
The Matrix ◽  
Culture Supernatants

S-ribosylhomocysteinase (LuxS) is required for the synthesis of the autoinducer-2 (AI-2) quorum-sensing signalling molecule in many Gram-negative bacteria. The bovine (and ovine) opportunistic pathogen Histophilus somni contains a luxS, and forms a biofilm containing an exopolysaccharide (EPS) in the matrix. Since biofilm formation is regulated by quorum sensing in many bacteria, the role of luxS in H. somni virulence and biofilm formation was investigated. Although culture supernatants from H. somni were ineffective at inducing bioluminescence in the Vibrio harveyi reporter strain BB170, H. somni luxS complemented the biosynthesis of AI-2 in the luxS-deficient Escherichia coli strain DH5α. H. somni strain 2336 luxS was inactivated by tranposon mutagenesis. Comparison of RNA exression profiles revealed that many genes were significantly differentially expressed in the luxS mutant compared to the wildtype, whether the bacteria were grown planktonically or in a biofilm. Furthermore, the luxS mutant had a truncated and asialylated lipooligosaccharide (LOS), and was substantially more serum-sensitive than the wildtype. Not surprisingly, the luxS mutant was attenuated in a mouse model for H. somni virulence, and some of the altered phenotypes were partially restored after the mutation was complemented with a functional luxS. However, no major differences were observed between the wildtype and the luxS mutant in regard to outer membrane protein profiles, biofilm formation, EPS production, or intracellular survival. These results indicate that luxS plays a role in H. somni virulence in the context of LOS biosynthesis, but not biofilm formation or other phenotypic properties examined.

scholarly journals Chemotaxis towards autoinducer 2 mediates autoaggregation in Escherichia coli

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Leanid Laganenka ◽  
Remy Colin ◽  
Victor Sourjik
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Physiological Role ◽  
Growth Conditions ◽  
Signal Molecules ◽  
E Coli ◽  
Autoinducer 2 ◽  
Cell Densities

Abstract Bacteria communicate by producing and sensing extracellular signal molecules called autoinducers. Such intercellular signalling, known as quorum sensing, allows bacteria to coordinate and synchronize behavioural responses at high cell densities. Autoinducer 2 (AI-2) is the only known quorum-sensing molecule produced by Escherichia coli but its physiological role remains elusive, although it is known to regulate biofilm formation and virulence in other bacterial species. Here we show that chemotaxis towards self-produced AI-2 can mediate collective behaviour—autoaggregation—of E. coli. Autoaggregation requires motility and is strongly enhanced by chemotaxis to AI-2 at physiological cell densities. These effects are observed regardless whether cell–cell interactions under particular growth conditions are mediated by the major E. coli adhesin (antigen 43) or by curli fibres. Furthermore, AI-2-dependent autoaggregation enhances bacterial stress resistance and promotes biofilm formation.

Sign in / Sign up

Export Citation Format

Share Document