scholarly journals Characterization of the Sinorhizobium meliloti sinR/sinI Locus and the Production of Novel N-Acyl Homoserine Lactones

2002 ◽  
Vol 184 (20) ◽  
pp. 5686-5695 ◽  
Author(s):  
Melanie M. Marketon ◽  
Matthew R. Gronquist ◽  
Anatol Eberhard ◽  
Juan E. González
Keyword(s):  
Quorum Sensing ◽  
Sinorhizobium Meliloti ◽  
Short Chain ◽  
Homoserine Lactones ◽  
Sensing System ◽  
Acyl Homoserine Lactones ◽  
Quorum Sensing System ◽  
Acyl Chains ◽  
Novel Structures

ABSTRACT Sinorhizobium meliloti is a soil bacterium which can establish a nitrogen-fixing symbiosis with the legume Medicago sativa. Recent work has identified a pair of genes, sinR and sinI, which represent a potential quorum-sensing system and are responsible for the production of N-acyl homoserine lactones (AHLs) in two S. meliloti strains, Rm1021 and Rm41. In this work, we characterize the sinRI locus and show that these genes are responsible for the synthesis of several long-chain AHLs ranging from 12 to 18 carbons in length. Four of these, 3-oxotetradecanoyl HL, 3-oxohexadecenoyl HL, hexadecenoyl HL, and octadecanoyl HL, have novel structures. This is the first report of AHLs having acyl chains longer than 14 carbons. We show that a disruption in sinI eliminates these AHLs and that a sinR disruption results in only basal levels of the AHLs. Moreover, the same sinI and sinR mutations also lead to a decrease in the number of pink nodules during nodulation assays, as well as a slight delay in the appearance of pink nodules, indicating a role for quorum sensing in symbiosis. We also show that sinI and sinR mutants are still capable of producing several short-chain AHLs, one of which was identified as octanoyl HL. We believe that these short-chain AHLs are evidence of a second quorum-sensing system in Rm1021, which we refer to here as the mel system, for “S. meliloti.”

Triazole-containing N-acyl homoserine lactones targeting the quorum sensing system in Pseudomonas aeruginosa

2015 ◽  
Vol 23 (7) ◽  
pp. 1638-1650 ◽  
Author(s):  
Mette R. Hansen ◽  
Tim H. Jakobsen ◽  
Claus G. Bang ◽  
Anders Emil Cohrt ◽  
Casper L. Hansen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Homoserine Lactones ◽  
Sensing System ◽  
Acyl Homoserine Lactones ◽  
Quorum Sensing System

scholarly journals Acidithiobacillus Its Application in Biomining Using a Quorum Sensing Modulation Approach

2021 ◽  
Author(s):  
Juan Carlos Caicedo ◽  
Sonia Villamizar
Keyword(s):  
Quorum Sensing ◽  
Communication System ◽  
Biofilm Formation ◽  
Cell Communication ◽  
Bacterial Attachment ◽  
Sensing System ◽  
Acyl Homoserine Lactones ◽  
Quorum Sensing System ◽  
Copper Gold ◽  
Acyl Chains

A group of particular acidophiles microorganisms (bacteria and archaea) known as chemolithoautotrophs are capable of using minerals as fuel. Its oxidation generates electrons to obtain energy and carbon that is obtained by fixing CO2 from the air. During this aerobic mineral oxidation, metals are solubilized or biodegraded. Metal bioleaching usually is used in biomining and urban biomining approaches to recovery metals such as copper, gold and zinc. Several species of bacterial genus Acidithiobacillus display a great bioleaching activity. Bacterial attachment and biofilm formation are the initial requirements to begin a successful bioleaching process. Biofilm formation in Acidithiobacillus bacteria is strongly regulated by cell to cell communication system called Quorum Sensing. The goal of this chapter is to review the Quorum Sensing system mediated by the autoinducer N-acyl- homoserine-lactones in the Bacterium Acidiothiobacillus ferroxidans, in order to enhance and to boost the bioleaching technologies based in the use of this bacterium. The main applications of the cell-to-cell communication system concepts in A. ferrooxidans are reviewed in this chapter. It is that the addition of synthetic autoinducers molecules, which act as agonist of quorum sensing system, especially those with long acyl chains, both as single molecules (C12-AHL, 3-hydroxy-C12-AHL, C14-AHL, and 3-hydroxy-C14-AHL) or as a mixture (C14-AHL/3- hydroxy-C14-AHL/3-oxo-C14-AHL) increased the adhesion to sulfur and pyrite and enhance the metal bioleaching in urban biomining approaches.

Identification and characterization of a LuxI/R-type quorum sensing system in Pseudoalteromonas

2019 ◽  
Vol 170 (6-7) ◽  
pp. 243-255 ◽  
Author(s):  
Zhiliang Yu ◽  
Dongliang Yu ◽  
Yanfeng Mao ◽  
Mengting Zhang ◽  
Mengdan Ding ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Identification And Characterization

scholarly journals The ExpR/Sin Quorum-Sensing System Controls Succinoglycan Production in Sinorhizobium meliloti

2007 ◽  
Vol 189 (19) ◽  
pp. 7077-7088 ◽  
Author(s):  
Sarah A. Glenn ◽  
Nataliya Gurich ◽  
Morgan A. Feeney ◽  
Juan E. González
Keyword(s):  
Molecular Weight ◽  
Quorum Sensing ◽  
Medicago Sativa ◽  
Sinorhizobium Meliloti ◽  
Direct Synthesis ◽  
Low Molecular Weight ◽  
Plant Host ◽  
Gram Negative ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACT Sinorhizobium meliloti is a gram-negative soil bacterium capable of forming a symbiotic nitrogen-fixing relationship with its plant host, Medicago sativa. Various bacterially produced factors are essential for successful nodulation. For example, at least one of two exopolysaccharides produced by S. meliloti (succinoglycan or EPS II) is required for nodule invasion. Both of these polymers are produced in high- and low-molecular-weight (HMW and LMW, respectively) fractions; however, only the LMW forms of either succinoglycan or EPS II are active in nodule invasion. The production of LMW succinoglycan can be generated by direct synthesis or through the depolymerization of HMW products by the action of two specific endoglycanases, ExsH and ExoK. Here, we show that the ExpR/Sin quorum-sensing system in S. meliloti is involved in the regulation of genes responsible for succinoglycan biosynthesis as well as in the production of LMW succinoglycan. Therefore, quorum sensing, which has been shown to regulate the production of EPS II, also plays an important role in succinoglycan biosynthesis.

scholarly journals The LuxR Homolog ExpR, in Combination with the Sin Quorum Sensing System, Plays a Central Role in Sinorhizobium meliloti Gene Expression

2004 ◽  
Vol 186 (16) ◽  
pp. 5460-5472 ◽  
Author(s):  
Hanh H. Hoang ◽  
Anke Becker ◽  
Juan E. González
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Sinorhizobium Meliloti ◽  
Regulation Of Gene Expression ◽  
Bacterial Communication ◽  
Cellular Processes ◽  
Sensing System ◽  
Dna Microarray Data ◽  
Luxr Homolog ◽  
Quorum Sensing System

ABSTRACT Quorum sensing, a population density-dependent mechanism for bacterial communication and gene regulation, plays a crucial role in the symbiosis between alfalfa and its symbiont Sinorhizobium meliloti. The Sin system, one of three quorum sensing systems present in S. meliloti, controls the production of the symbiotically active exopolysaccharide EPS II. Based on DNA microarray data, the Sin system also seems to regulate a multitude of S. meliloti genes, including genes that participate in low-molecular-weight succinoglycan production, motility, and chemotaxis, as well as other cellular processes. Most of the regulation by the Sin system is dependent on the presence of the ExpR regulator, a LuxR homolog. Gene expression profiling data indicate that ExpR participates in additional cellular processes that include nitrogen fixation, metabolism, and metal transport. Based on our microarray analysis we propose a model for the regulation of gene expression by the Sin/ExpR quorum sensing system and another possible quorum sensing system(s) in S. meliloti.

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