Functional Diversity of Quorum Sensing Receptors in Pathogenic Bacteria: Interspecies, Intraspecies and Interkingdom Level

2019 ◽  
Vol 20 (6) ◽  
pp. 655-667 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Aqib Javaid ◽  
Young-Mog Kim
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Behavioral Responses ◽  
Past Research ◽  
Signaling Molecules ◽  
Bacterial Virulence ◽  
Resistance Development ◽  
Inhibitory Molecules

The formation of biofilm by pathogenic bacteria is considered as one of the most powerful mechanisms/modes of resistance against the action of several antibiotics. Biofilm is formed as a structural adherent over the surfaces of host, food and equipments etc. and is further functionally coordinated by certain chemicals produced itself. These chemicals are known as quorum sensing (QS) signaling molecules and are involved in the cross talk at interspecies, intraspecies and interkingdom levels thus resulting in the production of virulence factors leading to pathogenesis. Bacteria possess receptors to sense these chemicals, which interact with the incoming QS molecules. It is followed by the secretion of virulence molecules, regulation of bioluminescence, biofilm formation, antibiotic resistance development and motility behavioral responses. In the natural environment, different bacterial species (Gram-positive and Gram-negative) produce QS signaling molecules that are structurally and functionally different. Recent and past research shows that various antagonistic molecules (naturally and chemically synthesized) are characterized to inhibit the formation of biofilm and attenuation of bacterial virulence by blocking the QS receptors. This review article describes about the diverse QS receptors at their structural, functional and production levels. Thus, by blocking these receptors with inhibitory molecules can be a potential therapeutic approach to control pathogenesis. Furthermore, these receptors can also be used as a structural platform to screen the most potent inhibitors with the help of bioinformatics approaches.

scholarly journals Specific quorum sensing molecules are possibly associated with responses to herbicide toxicity in a Pseudomonas strain

2020 ◽  
Author(s):  
Paloma Nathane Nunes de Freitas ◽  
Amanda Flávia da Silva Rovida ◽  
Caroline Rosa Silva ◽  
Sônia Alvim Veiga Pileggi ◽  
Luiz Ricardo Olchanheski ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Agricultural Production ◽  
Biofilm Formation ◽  
Structural Changes ◽  
Bacterial Species ◽  
Signaling Molecules ◽  
Oxygen Species ◽  
Physiological Plasticity ◽  
Response System ◽  
Generating System

AbstractPesticides contribute to pest control and increased agricultural production; however, they are toxic to non-target organisms and they contaminate the environment. The exposure of bacteria to these substances can lead to the need for physiological and structural changes for survival, which can be determined by genes whose expression is regulated by quorum sensing (QS). However, it is not yet clear whether these processes can be induced by herbicides. Thus, the aim of this work was to determine whether there is a QS response system in a Pseudomonas fluorescens strain that is modulated by herbicides. This strain was isolated from water storage tanks used for washing pesticide packaging and was tested against herbicides containing saflufenacil, glyphosate, sulfentrazone, 2,4-D, and dicamba as active molecules. We found that this strain possibly uses QS signaling molecules to control the production of reactive oxygen species, whether those produced by the bacterium’s energy generating system or by molecules induced by the presence of saflufenacil and glyphosate. This strain used other signaling molecules for various stages of biofilm formation in the presence of herbicides containing sulfentrazone, 2,4-D, and dicamba. These findings, as an initial screening which will guide new studies, suggest that this strain has a flexibility in gene expression that allows survival in the presence of several stress-inducing molecules, regardless of previous exposure. This represents a model of metabolic and physiological plasticity. Biofilms made up of several bacterial species can use this model in agricultural environments, increasing the potential for degradation of xenobiotics, but with impacts on diversity and functionality of microbiotas in these environments.

scholarly journals Characterization of Type 2 Quorum Sensing in Klebsiella pneumoniae and Relationship with Biofilm Formation

2005 ◽  
Vol 187 (8) ◽  
pp. 2870-2880 ◽  
Author(s):  
Damien Balestrino ◽  
Janus A. J. Haagensen ◽  
Chantal Rich ◽  
Christiane Forestier
Keyword(s):  
Quorum Sensing ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Microscopic Analysis ◽  
Opportunistic Pathogen ◽  
Signaling Molecules ◽  
Pcr Analysis

ABSTRACT Quorum sensing is a process by which bacteria communicate by using secreted chemical signaling molecules called autoinducers. Many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density by this mechanism. In this study, the opportunistic pathogen Klebsiella pneumoniae was observed to secrete type 2 signaling molecules. A homologue of luxS, the gene required for AI-2 synthesis in Vibrio harveyi, was isolated from the K. pneumoniae genome. A V. harveyi bioassay showed the luxS functionality in K. pneumoniae and its ability to complement the luxS-negative phenotype of Escherichia coli DH5α. Autoinducer activity was detected in the supernatant, and maximum expression of specific messengers detected by quantitative reverse transcription-PCR analysis occurred during the late exponential phase. The highest levels of AI-2 were observed in minimal medium supplemented with glycerol. To determine the potential role of luxS in colonization processes, a K. pneumoniae luxS isogenic mutant was constructed and tested for its capacity to form biofilms in vitro on an abiotic surface and to colonize the intestinal tract in a murine model. No difference was observed in the level of intestinal colonization between the wild-type strain and the luxS mutant. Microscopic analysis of biofilm structures revealed that the luxS mutant was able to form a mature biofilm but with reduced capacities in the development of microcolonies, mostly in the early steps of biofilm formation. These data suggest that a LuxS-dependent signal plays a role in the early stages of biofilm formation by K. pneumoniae.

scholarly journals Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by Vibrio Species

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Kyung-Jo Lee ◽  
You-Chul Jung ◽  
Soon-Jung Park ◽  
Kyu-Ho Lee
Keyword(s):  
Heat Shock ◽  
Quorum Sensing ◽  
Cell Density ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Capsular Polysaccharide ◽  
Signaling Molecules ◽  
Master Regulators

ABSTRACTCapsular polysaccharide (CPS) is essential for the dispersal of biofilms formed by the pathogenic bacteriumVibrio vulnificus. CPS production is induced by the quorum-sensing (QS) master regulator SmcR when biofilms mature. However,V. vulnificusbiofilms formed under heat shock conditions did not exhibit the dispersion stage. Transcripts of the CPS gene cluster were at basal levels in the heat-exposed cell owing to reduced cellular levels of SmcR. At least two proteases induced by heat shock, ClpPA and Lon, were responsible for determining the instability of SmcR.In vitroandin vivoassays demonstrated that SmcR levels were regulated via proteolysis by these proteases, with preferential proteolysis of monomeric SmcR. Thus, CPS production was not induced by QS when bacteria were heat treated. Further studies performed with otherVibriospecies demonstrated that high temperature deactivated the QS circuits by increased proteolysis of their QS master regulators, thus resulting in alterations to the QS-regulated phenotypes, including biofilm formation.IMPORTANCEThe term "quorum-sensing mechanism" is used to describe diverse bacterial cell density-dependent activities that are achieved by sensing of the signaling molecules and subsequent signal transduction to the master regulators. These well-known bacterial regulatory systems regulate the expression of diverse virulence factors and the construction of biofilms in pathogenic bacteria. There have been numerous studies designed to control bacterial quorum sensing by using small molecules to antagonize the quorum-sensing regulatory components or to interfere with the signaling molecules. In the present study, we showed that the quorum-sensing regulatory circuits of pathogenicVibriospecies were deactivated by heat shock treatment via highly increased proteolysis of the master transcription factors. Our results showed a new mode of quorum deactivation which can be achieved under conditions of high but nonlethal temperature even if the ambient signaling molecules may reach the levels representing high cell density.

Modulation of Gut Microbiota through Dietary Phytochemicals as a Novel Anti-infective Strategy

2020 ◽  
Vol 17 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Pavan K. Mujawdiya ◽  
Suman Kapur
Keyword(s):  
Microbial Community ◽  
Quorum Sensing ◽  
Population Density ◽  
Gut Microbiota ◽  
Biofilm Formation ◽  
Chemical Interaction ◽  
Bacterial Species ◽  
Critical Role ◽  
Bacterial Cells ◽  
Gut Microbes

: Quorum Sensing (QS) is a phenomenon in which bacterial cells communicate with each other with the help of several low molecular weight compounds. QS is largely dependent on population density, and it triggers when the concentration of quorum sensing molecules accumulate in the environment and crosses a particular threshold. Once a certain population density is achieved and the concentration of molecules crosses a threshold, the bacterial cells show a collective behavior in response to various chemical stimuli referred to as “auto-inducers”. The QS signaling is crucial for several phenotypic characteristics responsible for bacterial survival such as motility, virulence, and biofilm formation. Biofilm formation is also responsible for making bacterial cells resistant to antibiotics. : The human gut is home to trillions of bacterial cells collectively called “gut microbiota” or “gut microbes”. Gut microbes are a consortium of more than 15,000 bacterial species and play a very crucial role in several body functions such as metabolism, development and maturation of the immune system, and the synthesis of several essential vitamins. Due to its critical role in shaping human survival and its modulating impact on body metabolisms, the gut microbial community has been referred to as “the forgotten organ” by O`Hara et al. (2006) [1]. Several studies have demonstrated that chemical interaction between the members of bacterial cells in the gut is responsible for shaping the overall microbial community. : Recent advances in phytochemical research have generated a lot of interest in finding new, effective, and safer alternatives to modern chemical-based medicines. In the context of antimicrobial research various plant extracts have been identified with Quorum Sensing Inhibitory (QSI) activities among bacterial cells. This review focuses on the mechanism of quorum sensing and quorum sensing inhibitors isolated from natural sources.

scholarly journals Anti-quorum Sensing Potential of Ageratum Conyzoides L. (Asteraceae) Extracts

2021 ◽  
Author(s):  
Eli COMPAORE ◽  
Moussa COMPAORE ◽  
Vincent OUEDRAOGO ◽  
Ablassé ROUAMBA ◽  
Martin KIENDREBEOGO
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Methanolic Extract ◽  
Negative Impact ◽  
Significant Inhibition ◽  
High Morbidity ◽  
Ageratum Conyzoides ◽  
Phytochemical Content

Abstract Background: Pseudomonas aeruginosa causes infections in human particularly immunocompromised patients with cystic fibrosis, severe burns and HIV, resulting in high morbidity and mortality. The pathogenic bacteria P aeruginosa produces virulence factors regulated by the mechanism called quorum sensing system. Objective: The aim of this study was to assess the anti-quorum sensing activity of Ageratum conyzoides extracts Method: Chromobacterium violaceum reporter strain CV026 was used to highlight any interference with bacterium QS and strains derived from P. aeruginosa PAO1 were used to reveal any interference with the expression of quorum sensing genes, and to assess any impact of extract on the kinetics of the production of pyocyanin, elastases and biofilm formation. Results: Hydro-methanolic extract at the sub-inhibitory concentration of 100 μg/mL reduced quorum sensing virulence factors production such as, pyocyanin, elastases, rhamnolipids and biofilm formation in P. aeruginosa PAO1 after 18 hours monitoring. Extract showed significant inhibition in HSL-mediated violacein production on C. violaceum CV026 after 48 hours monitoring. Biofilm formation was inhibited up to 32%. It affected QS gene expression in PAO1. The regulatory genes lasR / rhlR and the lasI synthases were most affected. At 8hours, hydro-methanolic extract reduced both QS gene to more than 30% (lasI/lasR and rhlI/R respectively 33.8% /30.2% and 36% /33.2%). RhlA and lasB genes have been relatively affected (13.4% and 28.9%). After 18 h, this extract reduced significantly the expression of regulatory 30 genes lasR (31%) and rhlR (39.6%) although synthases genes seemed to be less affected (lasI/21.2% and rhlI/11.6%). A limited impact was observed on the downstream genes (lasB /20.0% and rhlA /15.3%). No negative impact was observed on CV026 and PAO1 growth and cell viability. Our study also showed that A. conyzoides having ample amount of phenolics, flavonoids and triterpenoids. This phytochemical content could be one of the factors for showing anti quorum potential. Conclusion: Results indicate that hydro methanol 80 % extract from A. conyzoides could be a source of potential QS inhibition compounds.

scholarly journals Quorum Sensing Influences Burkholderia thailandensis Biofilm Development and Matrix Production

2016 ◽  
Vol 198 (19) ◽  
pp. 2643-2650 ◽  
Author(s):  
Boo Shan Tseng ◽  
Charlotte D. Majerczyk ◽  
Daniel Passos da Silva ◽  
Josephine R. Chandler ◽  
E. Peter Greenberg ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Matrix Material ◽  
Close Relative ◽  
Wild Type ◽  
Flow Conditions ◽  
Burkholderia Thailandensis ◽  
Content Type ◽  
Biofilm Development

ABSTRACTMembers of the genusBurkholderiaare known to be adept at biofilm formation, which presumably assists in the survival of these organisms in the environment and the host. Biofilm formation has been linked to quorum sensing (QS) in several bacterial species. In this study, we characterizedBurkholderia thailandensisbiofilm development under flow conditions and sought to determine whether QS contributes to this process.B. thailandensisbiofilm formation exhibited an unusual pattern: the cells formed small aggregates and then proceeded to produce mature biofilms characterized by “dome” structures filled with biofilm matrix material. We showed that this process was dependent on QS.B. thailandensishas three acyl-homoserine lactone (AHL) QS systems (QS-1, QS-2, and QS-3). An AHL-negative strain produced biofilms consisting of cell aggregates but lacking the matrix-filled dome structures. This phenotype was rescued via exogenous addition of the three AHL signals. Of the threeB. thailandensisQS systems, we show that QS-1 is required for proper biofilm development, since abtaR1mutant, which is defective in QS-1 regulation, forms biofilms without these dome structures. Furthermore, our data show that the wild-type biofilm biomass, as well as the material inside the domes, stains with a fucose-binding lectin. ThebtaR1mutant biofilms, however, are negative for fucose staining. This suggests that the QS-1 system regulates the production of a fucose-containing exopolysaccharide in wild-type biofilms. Finally, we present data showing that QS ability during biofilm development produces a biofilm that is resistant to dispersion under stress conditions.IMPORTANCEThe saprophyteBurkholderia thailandensisis a close relative of the pathogenic bacteriumBurkholderia pseudomallei, the causative agent of melioidosis, which is contracted from its environmental reservoir. Since most bacteria in the environment reside in biofilms,B. thailandensisis an ideal model organism for investigating questions inBurkholderiaphysiology. In this study, we characterizedB. thailandensisbiofilm development and sought to determine if quorum sensing (QS) contributes to this process. Our work shows thatB. thailandensisproduces biofilms with unusual dome structures under flow conditions. Our findings suggest that these dome structures are filled with a QS-regulated, fucose-containing exopolysaccharide that may be involved in the resilience ofB. thailandensisbiofilms against changes in the nutritional environment.

scholarly journals Quorum-Sensing Mutations Affect Attachment and Stability of Burkholderia cenocepacia Biofilms

2005 ◽  
Vol 71 (9) ◽  
pp. 5208-5218 ◽  
Author(s):  
Kerry L. Tomlin ◽  
Rebecca J. Malott ◽  
Gordon Ramage ◽  
Douglas G. Storey ◽  
Pamela A. Sokol ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Cell Mass ◽  
Sodium Dodecyl ◽  
Burkholderia Cenocepacia ◽  
Structural Defects ◽  
Expression Vectors ◽  
Structural Development ◽  
The Individual

ABSTRACT Biofilm formation in Burkholderia cenocepacia has been shown to rely in part on acylhomoserine lactone-based quorum sensing. For many other bacterial species, it appears that both the initial adherence and the later stages of biofilm maturation are affected when quorum sensing pathways are inhibited. In this study, we examined the effects of mutations in the cepIR and cciIR quorum-sensing systems of Burkholderia cenocepacia K56-2 with respect to biofilm attachment and antibiotic resistance. We also examined the role of the cepIR system in biofilm stability and structural development. Using the high-throughput MBEC assay system to produce multiple equivalent biofilms, the biomasses of both the cepI and cepR mutant biofilms, measured by crystal violet staining, were less than half of the value observed for the wild-type strain. Attachment was partially restored upon providing functional gene copies via multicopy expression vectors. Surprisingly, neither the cciI mutant nor the double cciI cepI mutant was deficient in attachment, and restoration of the cciI gene resulted in less attachment than for the mutants. Meanwhile, the cciR mutant did show a significant reduction in attachment, as did the cciR cepIR mutant. While there was no change in antibiotic susceptibility with the individual cepIR and cciIR mutants, the cepI cciI mutant biofilms were more sensitive to ciprofloxacin. A significant increase in sensitivity to removal by sodium dodecyl sulfate was seen for the cepI and cepR mutants. Flow cell analysis of the individual cepIR mutant biofilms indicated that they were both structurally and temporally impaired in attachment and development. These results suggest that biofilm structural defects might be present in quorum-sensing mutants of B. cenocepacia that affect the stability and resistance of the adherent cell mass, providing a basis for future studies to design preventative measures against biofilm formation in this species, an important lung pathogen of cystic fibrosis patients.

scholarly journals LitR of Vibrio salmonicida Is a Salinity-Sensitive Quorum-Sensing Regulator of Phenotypes Involved in Host Interactions and Virulence

2012 ◽  
Vol 80 (5) ◽  
pp. 1681-1689 ◽  
Author(s):  
Ane Mohn Bjelland ◽  
Henning Sørum ◽  
Daget Ayana Tegegne ◽  
Hanne C. Winther-Larsen ◽  
Nils Peder Willassen ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Cold Water ◽  
Bacterial Species ◽  
Cell Communication ◽  
Cell Aggregation ◽  
Fish Host ◽  
Content Type ◽  
Vibrio Salmonicida

ABSTRACTVibrio(Aliivibrio)salmonicidais the causal agent of cold-water vibriosis, a fatal bacterial septicemia primarily of farmed salmonid fish. The molecular mechanisms of invasion, colonization, and growth ofV. salmonicidain the host are still largely unknown, and few virulence factors have been identified. Quorum sensing (QS) is a cell-to-cell communication system known to regulate virulence and other activities in several bacterial species. The genome ofV. salmonicidaLFI1238 encodes products presumably involved in several QS systems. In this study, the gene encoding LitR, a homolog of the master regulator of QS inV. fischeri, was deleted. Compared to the parental strain, thelitRmutant showed increased motility, adhesion, cell-to-cell aggregation, and biofilm formation. Furthermore, thelitRmutant produced less cryptic bioluminescence, whereas production of acylhomoserine lactones was unaffected. Our results also indicate a salinity-sensitive regulation of LitR. Finally, reduced mortality was observed in Atlantic salmon infected with thelitRmutant, implying that the fish were more susceptible to infection with the wild type than with the mutant strain. We hypothesize that LitR inhibits biofilm formation and favors planktonic growth, with the latter being more adapted for pathogenesis in the fish host.

scholarly journals Interaction between Streptococcus spp. and Veillonella tobetsuensis in the Early Stages of Oral Biofilm Formation

2015 ◽  
Vol 197 (13) ◽  
pp. 2104-2111 ◽  
Author(s):  
Izumi Mashima ◽  
Futoshi Nakazawa
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Signaling Molecules ◽  
Dependent Manner ◽  
Oral Biofilm ◽  
Metabolic Cooperation ◽  
Content Type ◽  
Early Stages ◽  
Oral Biofilms ◽  
Culture Supernatants

Dental plaque is a multispecies oral biofilm, the development of which is initiated by adherence of the pioneerStreptococcusspp. OralVeillonellaspp., includingV. atypica,V. denticariosi,V. dispar,V. parvula,V. rogosae, andV. tobetsuensis, are known as early colonizers in oral biofilm formation. These species have been reported to coaggregate withStreptococcusspp. in a metabolic cooperation-dependent manner to form biofilms in human oral cavities, especially in the early stages of biofilm formation. However, in our previous study,Streptococcus gordoniishowed biofilm formation to the greatest extent in the presence ofV. tobetsuensis, without coaggregation between species. These results suggest thatV. tobetsuensisproduces signaling molecules that promote the proliferation ofS. gordoniiin biofilm formation. It is well known in many bacterial species that the quorum-sensing (QS) system regulates diverse functions such as biofilm formation. However, little is known about the QS system with autoinducers (AIs) with respect toVeillonella and Streptococcusspp. Recently, autoinducer 1 (AI-1) and AI-2 were detected and identified in the culture supernatants ofV. tobetsuensisas strong signaling molecules in biofilm formation withS. gordonii. In particular, the supernatant fromV. tobetsuensisshowed the highest AI-2 activity among 6 oralVeillonellaspecies, indicating that AIs, mainly AI-2, produced byV. tobetsuensismay be important factors and may facilitate biofilm formation ofS. gordonii. Clarifying the mechanism that underlies the QS system betweenS. gordoniiandV. tobetsuensismay lead to the development of novel methods for the prevention of oral infectious diseases caused by oral biofilms.

scholarly journals AHL-Lactonase Producing Psychrobacter sp. From Palk Bay Sediment Mitigates Quorum Sensing-Mediated Virulence Production in Gram Negative Bacterial Pathogens

2021 ◽  
Vol 12 ◽  
Author(s):  
Issac Abraham Sybiya Vasantha Packiavathy ◽  
Arunachalam Kannappan ◽  
Sivaprakasam Thiyagarajan ◽  
Ramanathan Srinivasan ◽  
Danaraj Jeyapragash ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Marine Sediment ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Proteinase K ◽  
Ring Cleavage ◽  
Heat Inactivation ◽  
Sediment Bacteria ◽  
Palk Bay

Quorum sensing (QS) is a signaling mechanism governed by bacteria used to converse at inter- and intra-species levels through small self-produced chemicals called N-acylhomoserine lactones (AHLs). Through QS, bacteria regulate and organize the virulence factors’ production, including biofilm formation. AHLs can be degraded by an action called quorum quenching (QQ) and hence QQ strategy can effectively be employed to combat biofilm-associated bacterial pathogenesis. The present study aimed to identify novel bacterial species with QQ potential. Screening of Palk Bay marine sediment bacteria for QQ activity ended up with the identification of marine bacterial isolate 28 (MSB-28), which exhibited a profound QQ activity against QS biomarker strain Chromobacterium violaceum ATCC 12472. The isolate MSB-28 was identified as Psychrobacter sp. through 16S-rRNA sequencing. Psychrobacter sp. also demonstrated a pronounced activity in controlling the biofilm formation in different bacteria and biofilm-associated virulence factors’ production in P. aeruginosa PAO1. Solvent extraction, heat inactivation, and proteinase K treatment assays clearly evidence the enzymatic nature of the bioactive lead. Furthermore, AHL’s lactone ring cleavage was confirmed with experiments including ring closure assay and chromatographic analysis, and thus the AHL-lactonase enzyme production in Psychrobacter sp. To conclude, this is the first report stating the AHL-lactonase mediated QQ activity from marine sediment bacteria Psychrobacter sp. Future work deals with the characterization, purification, and mass cultivation of the purified protein and should pave the way to assessing the feasibility of the identified protein in controlling QS and biofilm-mediated multidrug resistant bacterial infections in mono or multi-species conditions.

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