scholarly journals Quorum-sensing regulation in rhizobia and its role in symbiotic interactions with legumes

2007 ◽  
Vol 362 (1483) ◽  
pp. 1149-1163 ◽  
Author(s):  
Maria Sanchez-Contreras ◽  
Wolfgang D Bauer ◽  
Mengsheng Gao ◽  
Jayne B Robinson ◽  
J Allan Downie
Keyword(s):  
Quorum Sensing ◽  
Potential Role ◽  
Active Role ◽  
Dependent Manner ◽  
Homoserine Lactones ◽  
Signalling Molecules ◽  
Sensing Systems ◽  
Symbiotic Interactions ◽  
Regulatory Systems

Legume-nodulating bacteria (rhizobia) usually produce N -acyl homoserine lactones, which regulate the induction of gene expression in a quorum-sensing (or population-density)-dependent manner. There is significant diversity in the types of quorum-sensing regulatory systems that are present in different rhizobia and no two independent isolates worked on in detail have the same complement of quorum-sensing genes. The genes regulated by quorum sensing appear to be rather diverse and many are associated with adaptive aspects of physiology that are probably important in the rhizosphere. It is evident that some aspects of rhizobial physiology related to the interaction between rhizobia and legumes are influenced by quorum sensing. However, it also appears that the legumes play an active role, both in terms of interfering with the rhizobial quorum-sensing systems and responding to the signalling molecules made by the bacteria. In this article, we review the diversity of quorum-sensing regulation in rhizobia and the potential role of legumes in influencing and responding to this signalling system.

scholarly journals raiIR Genes Are Part of a Quorum-Sensing Network Controlled by cinI and cinR in Rhizobium leguminosarum

2002 ◽  
Vol 184 (6) ◽  
pp. 1597-1606 ◽  
Author(s):  
F. Wisniewski-Dyé ◽  
J. Jones ◽  
S. R. Chhabra ◽  
J. A. Downie
Keyword(s):  
Quorum Sensing ◽  
Rhizobium Leguminosarum ◽  
Homoserine Lactone ◽  
Major Product ◽  
Homoserine Lactones ◽  
Indigenous Plasmid ◽  
Sensing Systems ◽  
Regulatory Systems ◽  
Normal Expression ◽  
Low Levels

ABSTRACT Analysis of N-acyl-l-homoserine lactones (AHLs) produced by Rhizobium leguminosarum bv. viciae indicated that there may be a network of quorum-sensing regulatory systems producing multiple AHLs in this species. Using a strain lacking a symbiosis plasmid, which carries some of the quorum-sensing genes, we isolated mutations in two genes (raiI and raiR) that are required for production of AHLs. The raiIR genes are located adjacent to dad genes (involved in d-alanine catabolism) on a large indigenous plasmid. RaiR is predicted to be a typical LuxR-type quorum-sensing regulator and is required for raiI expression. The raiR gene was expressed at a low level, possibly from a constitutive promoter, and its expression was increased under the influence of the upstream raiI promoter. Using gene fusions and analysis of AHLs produced, we showed that expression of raiI is strongly reduced in strains carrying mutations in cinI or cinR, genes which determine a higher-level quorum-sensing system that is required for normal expression of raiIR. The product of CinI, N-(3-hydroxy-7-cis tetradecenoyl) homoserine lactone, can induce raiR-dependent raiI expression, although higher levels of expression are induced by other AHLs. Expression of raiI in a strain of Agrobacterium that makes no AHLs resulted in the identification of N-(3-hydroxyoctanoyl)-l-homoserine lactone (3OH,C8-HSL) as the major product of RaiI, although other AHLs that comigrate with N-hexanoyl-, N-heptanoyl-, and N-octanoyl-homoserine lactones were also made at low levels. The raiI gene was strongly induced by 3OH,C8-HSL (the product of RaiI) but could also be induced by other AHLs, suggesting that the raiI promoter can be activated by other quorum-sensing systems within a network of regulation which also involves AHLs determined by genes on the symbiotic plasmid. Thus, the raiIR and cinIR genes are part of a complex regulatory network that influences AHL biosynthesis in R. leguminosarum.

Potential role of probiotics in reducing Clostridioides difficile virulence: Interference with quorum sensing systems

2021 ◽  
Vol 153 ◽  
pp. 104798
Author(s):  
Sathursha Gunaratnam ◽  
Mathieu Millette ◽  
Lynne V. McFarland ◽  
Herbert L. DuPont ◽  
Monique Lacroix
Keyword(s):  
Quorum Sensing ◽  
Potential Role ◽  
Clostridioides Difficile ◽  
Sensing Systems

scholarly journals PapRIV, a BV-2 microglial cell activating quorum sensing peptide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yorick Janssens ◽  
Nathan Debunne ◽  
Anton De Spiegeleer ◽  
Evelien Wynendaele ◽  
Marta Planas ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cell Model ◽  
Dependent Manner ◽  
Communication Signals ◽  
Gram Positive Bacteria ◽  
A Cell ◽  
Gastro Intestinal Tract

AbstractQuorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction.

Growth of Salmonella Enteritidis in the presence of quorum sensing signaling compounds produced by Pseudomonas aeruginosa

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Weijia He ◽  
Huamei Yang ◽  
Xiang Wang ◽  
Hongmei Li ◽  
Qingli Dong
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Salmonella Enteritidis ◽  
Culture Supernatant ◽  
Lag Time ◽  
Bacterial Communication ◽  
Homoserine Lactones ◽  
Positive Effects ◽  
Kinetics Of

Abstract Quorum sensing (QS) can exist in food-related bacteria and potentially affect bacterial growth through acyl-homoserine lactones (AHLs). To verify the role of QS compounds in the cell-free supernatant, this study examined the effect of supernatant extracted from Pseudomonas aeruginosa culture on the growth kinetics of Salmonella Enteritidis. The results showed that the lag time (λ) of S. Enteritidis was apparently reduced (p < 0.05) under the influence of P. aeruginosa culture supernatant compared with the S. Enteritidis culture supernatant. HPLC-MS/MS test demonstrated that AHLs secreted by P. aeruginosa were mainly C14-HSL with a content of 85.71 μg/mL and a small amount of 3-oxo-C12-HSL. In addition, the commercially synthetic C14-HSL had positive effects on the growth of S. Enteritidis, confirming once again that the growth of S. Enteritidis was affected by AHL metabolized by other bacteria and the complexity of bacterial communication.

scholarly journals The action of α-adrenergic agonists on plasma-membrane calcium fluxes in perfused rat liver

1984 ◽  
Vol 220 (1) ◽  
pp. 43-50 ◽  
Author(s):  
P H Reinhart ◽  
W M Taylor ◽  
F L Bygrave
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Potential Role ◽  
Dependent Manner ◽  
Perfused Rat Liver ◽  
Adrenergic Agonists ◽  
Mediated Effects ◽  
Alpha Agonist ◽  
Alpha Adrenergic Agonist

The effect of alpha-adrenergic agonists on Ca2+ fluxes was examined in the perfused rat liver by using a combination of Ca2+-electrode and 45Ca2+-uptake techniques. We showed that net Ca2+ fluxes can be described by the activities of separate Ca2+-uptake and Ca2+-efflux components, and that alpha-adrenergic agonists modulate the activity of both components in a time-dependent manner. Under resting conditions, Ca2+-uptake and -efflux activities are balanced, resulting in Ca2+ cycling across the plasma membrane. The alpha-adrenergic agonists vasopressin and angiotensin, but not glucagon, stimulate the rate of both Ca2+ efflux and Ca2+ uptake. During the first 2-3 min of alpha-agonist administration the effect on the efflux component is the greater, the net effect being efflux of Ca2+ from the cell. After 3-4 min of phenylephrine treatment, net Ca2+ movements are essentially complete, however, the rate of Ca2+ cycling is significantly increased. After removal of the alpha-agonist a large stimulation of the rate of Ca2+ uptake leads to the net accumulation of Ca2+ by the cell. The potential role of these Ca2+ flux changes in the expression of alpha-adrenergic-agonist-mediated effects is discussed.

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 Large-scale identification of viral quorum sensing systems reveal convergent evolution of density-dependent sporulation-hijacking in bacteriophages

2021 ◽  
Author(s):  
Charles Bernard ◽  
Yanyan Li ◽  
Philippe Lopez ◽  
Eric Bapteste
Keyword(s):  
Quorum Sensing ◽  
Large Scale ◽  
Supporting Cell ◽  
Computational Method ◽  
Dependent Manner ◽  
Genomic Context ◽  
Density Dependent ◽  
Sensing Systems ◽  
Public Data ◽  
Genetic Systems

Quorum sensing systems (QSSs) are genetic systems supporting cell-cell or bacteriophage-bacteriophage communication. By regulating behavioral switches as a function of the encoding population density, QSSs shape the social dynamics of microbial communities. However, their diversity is tremendously overlooked in bacteriophages, which implies that many density-dependent behaviors likely remains to be discovered in these viruses. Here, we developed a signature-based computational method to identify novel peptide-based RRNPP QSSs in gram-positive bacteria (e.g. Firmicutes) and their mobile genetic elements. The large-scale application of this method against available genomes of Firmicutes and bacteriophages revealed 2708 candidate RRNPP-type QSSs, including 382 found in (pro)phages. These 382 viral candidate QSSs are classified into 25 different groups of homologs, of which 22 were never described before in bacteriophages. Remarkably, genomic context analyses suggest that candidate viral QSSs from 6 different families dynamically manipulate the host biology. Specifically, many viral candidate QSSs are predicted to regulate, in a density-dependent manner, adjacent (pro)phage-encoded regulator genes whose bacterial homologs are key regulators of the sporulation initiation pathway (either Rap, Spo0E, or AbrB). Consistently, we found evidence from public data that certain of our candidate (pro)phage-encoded QSSs dynamically manipulate the timing of sporulation of the bacterial host. These findings challenge the current paradigm assuming that bacteria decide to sporulate in adverse situation. Indeed, our survey highlights that bacteriophages have evolved, multiple times, genetic systems that dynamically influence this decision to their advantage, making sporulation a survival mechanism of last resort for phage-host collectives.

PtdIns5P: a little phosphoinositide with big functions?

2007 ◽  
Vol 74 ◽  
pp. 117-128 ◽  
Author(s):  
Sophie Coronas ◽  
Damien Ramel ◽  
Caroline Pendaries ◽  
Frédérique Gaits-Iacovoni ◽  
Hélène Tronchère ◽  
...  
Keyword(s):  
Potential Role ◽  
Current Knowledge ◽  
Critical Role ◽  
Cell Regulation ◽  
Cellular Functions ◽  
Minor Constituents ◽  
Signalling Molecules ◽  
Phosphoinositide 3 Kinase ◽  
Synthesis And Degradation

Phosphoinositides are minor constituents of cell membranes playing a critical role in the regulation of many cellular functions. Recent discoveries indicate that mutations in several phosphoinositide kinases and phosphatases generate imbalances in the levels of phosphoinositides, thereby leading to the development of human diseases. Although the roles of phosphoinositide 3-kinase products and PtdIns(4,5)P2 were largely studied these last years, the potential role of phosphatidylinositol monophosphates as direct signalling molecules is just emerging. PtdIns5P, the least characterized phosphoinositide, appears to be a new player in cell regulation. This review will summarize the current knowledge on the mechanisms of synthesis and degradation of PtdIns5P as well as its potential roles.

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