MathematicalModels of Quorum Sensing Molecular Mechanisms

2020 ◽  
pp. 25-37
Author(s):  
Sarangam Majumdar ◽  
Sisir Roy
Keyword(s):  
Quorum Sensing ◽  
Molecular Mechanisms

scholarly journals Cross-kingdom inhibition of bacterial virulence and communication by probiotic yeast metabolites

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Orit Malka ◽  
Dorin Kalson ◽  
Karin Yaniv ◽  
Reut Shafir ◽  
Manikandan Rajendran ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Gut Microbiome ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Molecular Mechanisms ◽  
Human Microbiome ◽  
Cell Communication ◽  
Probiotic Yeast ◽  
Gut Pathogen ◽  
Cell Cell

Abstract Background Probiotic milk-fermented microorganism mixtures (e.g., yogurt, kefir) are perceived as contributing to human health, and possibly capable of protecting against bacterial infections. Co-existence of probiotic microorganisms are likely maintained via complex biomolecular mechanisms, secreted metabolites mediating cell-cell communication, and other yet-unknown biochemical pathways. In particular, deciphering molecular mechanisms by which probiotic microorganisms inhibit proliferation of pathogenic bacteria would be highly important for understanding both the potential benefits of probiotic foods as well as maintenance of healthy gut microbiome. Results The microbiome of a unique milk-fermented microorganism mixture was determined, revealing a predominance of the fungus Kluyveromyces marxianus. We further identified a new fungus-secreted metabolite—tryptophol acetate—which inhibits bacterial communication and virulence. We discovered that tryptophol acetate blocks quorum sensing (QS) of several Gram-negative bacteria, particularly Vibrio cholerae, a prominent gut pathogen. Notably, this is the first report of tryptophol acetate production by a yeast and role of the molecule as a signaling agent. Furthermore, mechanisms underscoring the anti-QS and anti-virulence activities of tryptophol acetate were elucidated, specifically down- or upregulation of distinct genes associated with V. cholerae QS and virulence pathways. Conclusions This study illuminates a yet-unrecognized mechanism for cross-kingdom inhibition of pathogenic bacteria cell-cell communication in a probiotic microorganism mixture. A newly identified fungus-secreted molecule—tryptophol acetate—was shown to disrupt quorum sensing pathways of the human gut pathogen V. cholerae. Cross-kingdom interference in quorum sensing may play important roles in enabling microorganism co-existence in multi-population environments, such as probiotic foods and the gut microbiome. This discovery may account for anti-virulence properties of the human microbiome and could aid elucidating health benefits of probiotic products against bacterially associated diseases.

scholarly journals Research progress on the antibacterial mechanisms of carvacrol: a mini review

2018 ◽  
Vol 1 (6) ◽  
pp. 71
Author(s):  
Dan Zhang ◽  
Ren-You Gan ◽  
Ying-Ying Ge ◽  
Qiong-Qiong Yang ◽  
Jiao Ge ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Antibacterial Activity ◽  
Quorum Sensing ◽  
Cell Membrane ◽  
Molecular Mechanisms ◽  
Food Preservation ◽  
Research Progress ◽  
Oxygen Species ◽  
Aromatic Plants ◽  
Volatile Oils

Background: Carvacrol is an aromatic phenolic terpenoid widely existing in the volatile oils of thyme, oregano, and some other aromatic plants. Recent studies have found that carvacrol possesses excellent antibacterial activity. In order to provide an updated information about the antibacterial potentials of carvacrol, herein, we summarized recent publications about the antibacterial activity of carvacrol, with special attention paid to its antibacterial molecular mechanisms, including desrupting cell membrane, depleting intracellular ATP, inducing reactive oxygen species, inhibiting efflux pumps, as well as suppressing two important virulence factors, biofilm and quorum sensing. In conclusion, carvacrol is a promising natural antibacterial compound with potential application in food preservation and infection.Keywords：Carvacrol, antibacterial mechanisms, biofilm, quorum sensing

scholarly journals Bacterial Quorum-Quenching Lactonase Hydrolyzes Fungal Mycotoxin and Reduces Pathogenicity of Penicillium expansum—Suggesting a Mechanism of Bacterial Antagonism

2021 ◽  
Vol 7 (10) ◽  
pp. 826
Author(s):  
Shlomit Dor ◽  
Dov Prusky ◽  
Livnat Afriat-Jurnou
Keyword(s):  
Cell Wall ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Molecular Mechanisms ◽  
Recombinant Expression ◽  
Bacterial Species ◽  
Quorum Quenching ◽  
Host Cells ◽  
Penicillium Expansum ◽  
Fungal Colonization

Penicillium expansum is a necrotrophic wound fungal pathogen that secrets virulence factors to kill host cells including cell wall degrading enzymes (CWDEs), proteases, and mycotoxins such as patulin. During the interaction between P. expansum and its fruit host, these virulence factors are strictly modulated by intrinsic regulators and extrinsic environmental factors. In recent years, there has been a rapid increase in research on the molecular mechanisms of pathogenicity in P. expansum; however, less is known regarding the bacteria–fungal communication in the fruit environment that may affect pathogenicity. Many bacterial species use quorum-sensing (QS), a population density-dependent regulatory mechanism, to modulate the secretion of quorum-sensing signaling molecules (QSMs) as a method to control pathogenicity. N-acyl homoserine lactones (AHLs) are Gram-negative QSMs. Therefore, QS is considered an antivirulence target, and enzymes degrading these QSMs, named quorum-quenching enzymes, have potential antimicrobial properties. Here, we demonstrate that a bacterial AHL lactonase can also efficiently degrade a fungal mycotoxin. The mycotoxin is a lactone, patulin secreted by fungi such as P. expansum. The bacterial lactonase hydrolyzed patulin at high catalytic efficiency, with a kcat value of 0.724 ± 0.077 s−1 and KM value of 116 ± 33.98 μM. The calculated specific activity (kcat/KM) showed a value of 6.21 × 103 s−1M−1. While the incubation of P. expansum spores with the purified lactonase did not inhibit spore germination, it inhibited colonization by the pathogen in apples. Furthermore, adding the purified enzyme to P. expansum culture before infecting apples resulted in reduced expression of genes involved in patulin biosynthesis and fungal cell wall biosynthesis. Some AHL-secreting bacteria also express AHL lactonase. Here, phylogenetic and structural analysis was used to identify putative lactonase in P. expansum. Furthermore, following recombinant expression and purification of the newly identified fungal enzyme, its activity with patulin was verified. These results indicate a possible role for patulin and lactonases in inter-kingdom communication between fungi and bacteria involved in fungal colonization and antagonism and suggest that QQ lactonases can be used as potential antifungal post-harvest treatment.

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.

Molecular Mechanisms ofagr Quorum Sensing in Virulent Staphylococci

ChemBioChem ◽  
2007 ◽  
Vol 8 (8) ◽  
pp. 847-855 ◽  
Author(s):  
Elizabeth A. George ◽  
Tom W. Muir
Keyword(s):  
Quorum Sensing ◽  
Molecular Mechanisms

scholarly journals Recent Advances in the Mechanisms and Regulation of QS in Dairy Spoilage by Pseudomonas spp.

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3088
Author(s):  
Laura Quintieri ◽  
Leonardo Caputo ◽  
Milena Brasca ◽  
Francesca Fanelli
Keyword(s):  
Quorum Sensing ◽  
Low Temperatures ◽  
Metabolic Pathways ◽  
Dairy Products ◽  
Molecular Mechanisms ◽  
Multidrug Resistant ◽  
Food Spoilage ◽  
Homoserine Lactones ◽  
Quality And Shelf Life

Food spoilage is a serious issue dramatically impacting the worldwide need to counteract food insecurity. Despite the very expensive application of low temperatures, the proper conservation of fresh dairy products is continuously threatened at different stages of production and commercialization by psychrotrophic populations mainly belonging to the Pseudomonas genus. These bacteria cause discolouration, loss of structure, and off-flavours, with fatal implications on the quality and shelf-life of products. While the effects of pseudomonad decay have been widely reported, the mechanisms responsible for the activation and regulation of spoilage pathways are still poorly explored. Recently, molecule signals and regulators involved in quorum sensing (QS), such as homoserine lactones, the luxR/luxI system, hdtS, and psoR, have been detected in spoiled products and bacterial spoiler species; this evidence suggests the role of bacterial cross talk in dairy spoilage and paves the way towards the search for novel preservation strategies based on QS inhibition. The aim of this review was to investigate the advancements achieved by the application of omic approaches in deciphering the molecular mechanisms controlled by QS systems in pseudomonads, by focusing on the regulators and metabolic pathways responsible for spoilage of fresh dairy products. In addition, due the ability of pseudomonads to quickly spread in the environment as biofilm communities, which may also include pathogenic and multidrug-resistant (MDR) species, the risk derived from the gaps in clearly defined and regulated sanitization actions is underlined.

scholarly journals Bacterial Quorum Sensing and Microbial Community Interactions

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Rhea G. Abisado ◽  
Saida Benomar ◽  
Jennifer R. Klaus ◽  
Ajai A. Dandekar ◽  
Josephine R. Chandler
Keyword(s):  
Quorum Sensing ◽  
Bacterial Infections ◽  
Molecular Mechanisms ◽  
Cell Communication ◽  
Microbial Interactions ◽  
Community Interactions ◽  
Bacterial Populations ◽  
Bacterial Quorum Sensing ◽  
A Cell ◽  
Bacterial Quorum

ABSTRACTMany bacteria use a cell-cell communication system called quorum sensing to coordinate population density-dependent changes in behavior. Quorum sensing involves production of and response to diffusible or secreted signals, which can vary substantially across different types of bacteria. In many species, quorum sensing modulates virulence functions and is important for pathogenesis. Over the past half-century, there has been a significant accumulation of knowledge of the molecular mechanisms, signal structures, gene regulons, and behavioral responses associated with quorum-sensing systems in diverse bacteria. More recent studies have focused on understanding quorum sensing in the context of bacterial sociality. Studies of the role of quorum sensing in cooperative and competitive microbial interactions have revealed how quorum sensing coordinates interactions both within a species and between species. Such studies of quorum sensing as a social behavior have relied on the development of “synthetic ecological” models that use nonclonal bacterial populations. In this review, we discuss some of these models and recent advances in understanding how microbes might interact with one another using quorum sensing. The knowledge gained from these lines of investigation has the potential to guide studies of microbial sociality in natural settings and the design of new medicines and therapies to treat bacterial infections.

Quorum Sensing Regulation as a Target for Antimicrobial Therapy

2021 ◽  
Vol 21 ◽  
Author(s):  
Caterine Henríquez Ruiz ◽  
Estefanie Osorio-Llanes ◽  
Mayra Hernández Trespalacios ◽  
Evelyn Mendoza-Torres ◽  
Wendy Rosales ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Cell Communication ◽  
Structural Evolution ◽  
Structural Diversity ◽  
Signal Molecules ◽  
Bacterial Survival

: Some bacterial species use a cell-to-cell communication mechanism called Quorum Sensing (QS). Bacteria release small diffusible molecules, usually termed signals which allow the activation of beneficial phenotypes that guarantee bacterial survival and the expression of a diversity of virulence genes in response to an increase in population density. The study of the molecular mechanisms that relate signal molecules with bacterial pathogenesis is an area of growing interest due to its use as a possible therapeutic alternative through the development of synthetic analogues of autoinducers as a strategy to regulate bacterial communication as well as the study of bacterial resistance phenomena, the study of these relationships is based on the structural diversity of natural or synthetic autoinducers and their ability to inhibit bacterial QS, which can be approached with a molecular perspective from the following topics: i) Molecular signals and their role in QS regulation; ii) Strategies in the modulation of Quorum Sensing; iii) Analysis of Bacterial QS circuit regulation strategies; iv) Structural evolution of natural and synthetic autoinducers as QS regulators. This mini-review allows a molecular view of the QS systems, showing a perspective on the importance of the molecular diversity of autoinducer analogs as a strategy for the design of new antimicrobial agents.

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