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Quorum sensing and bacterial social interactions in biofilms.

Li YH, Tian X - Sensors (Basel) (2012)

Bottom Line: Many bacteria are known to regulate their cooperative activities and physiological processes through a mechanism called quorum sensing (QS), in which bacterial cells communicate with each other by releasing, sensing and responding to small diffusible signal molecules.The ability of bacteria to communicate and behave as a group for social interactions like a multi-cellular organism has provided significant benefits to bacteria in host colonization, formation of biofilms, defense against competitors, and adaptation to changing environments.Therefore, understanding the molecular details of quorum sensing mechanisms and their controlled social activities may open a new avenue for controlling bacterial infections.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada. yung-hua.li@dal.ca

ABSTRACT
Many bacteria are known to regulate their cooperative activities and physiological processes through a mechanism called quorum sensing (QS), in which bacterial cells communicate with each other by releasing, sensing and responding to small diffusible signal molecules. The ability of bacteria to communicate and behave as a group for social interactions like a multi-cellular organism has provided significant benefits to bacteria in host colonization, formation of biofilms, defense against competitors, and adaptation to changing environments. Importantly, many QS-controlled activities have been involved in the virulence and pathogenic potential of bacteria. Therefore, understanding the molecular details of quorum sensing mechanisms and their controlled social activities may open a new avenue for controlling bacterial infections.

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Related in: MedlinePlus

The LuxI/LuxR–type quorum sensing in Gram-negative bacteria. The LuxI-like protein is an autoinducer synthase that catalyzes the formation of a specific acyl-homoserine lactone (AHL). The AHL freely diffuses through the cell membrane at high cell density. The LuxR is a transcriptional regulator that binds to the diffusing AHL and in turn activates the transcription of its target genes.
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f1-sensors-12-02519: The LuxI/LuxR–type quorum sensing in Gram-negative bacteria. The LuxI-like protein is an autoinducer synthase that catalyzes the formation of a specific acyl-homoserine lactone (AHL). The AHL freely diffuses through the cell membrane at high cell density. The LuxR is a transcriptional regulator that binds to the diffusing AHL and in turn activates the transcription of its target genes.

Mentions: In Gram-negative bacteria, signal molecules are acyl-homoserine lactones (AHL) whose synthesis is dependent on a LuxI-like protein [28–30]. AHLs freely diffuse across the cell membrane and increase in concentration in proportion to cell density. A cognate LuxR-like protein is responsible for recognition of the AHL and when bound to the AHL, LuxR-like protein binds to specific promoter DNA elements and activates transcription of target genes (Figure 1). The biochemical mechanism of action of the LuxI/LuxR pairs is conserved. The LuxI-like enzymes produce a specific AHL by coupling the acyl-side chain of a specific acyl-acyl carrier protein (acyl-ACP) from the fatty acid biosynthetic machinery to the homocysteine moiety of S-adenosylmethionine (SAM). This intermediate lactonizes to form acyl-HSL, releasing methylthioadenosine [28,29]. There are hundreds of Gram-negative bacteria identified to use LuxI/LuxR-type quorum sensing to control a wide range of cellular processes. Each species produces a unique AHL or a unique combination of AHL and, as a result, only the members of the same species recognize and respond to its own signal molecule [7,8,25,28]. Many other examples of Gram-negative circuits exist that utilize a LuxI/LuxR-type quorum sensing mechanism onto which additional regulatory factors have been layered [7–9,25–30].


Quorum sensing and bacterial social interactions in biofilms.

Li YH, Tian X - Sensors (Basel) (2012)

The LuxI/LuxR–type quorum sensing in Gram-negative bacteria. The LuxI-like protein is an autoinducer synthase that catalyzes the formation of a specific acyl-homoserine lactone (AHL). The AHL freely diffuses through the cell membrane at high cell density. The LuxR is a transcriptional regulator that binds to the diffusing AHL and in turn activates the transcription of its target genes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376616&req=5

f1-sensors-12-02519: The LuxI/LuxR–type quorum sensing in Gram-negative bacteria. The LuxI-like protein is an autoinducer synthase that catalyzes the formation of a specific acyl-homoserine lactone (AHL). The AHL freely diffuses through the cell membrane at high cell density. The LuxR is a transcriptional regulator that binds to the diffusing AHL and in turn activates the transcription of its target genes.
Mentions: In Gram-negative bacteria, signal molecules are acyl-homoserine lactones (AHL) whose synthesis is dependent on a LuxI-like protein [28–30]. AHLs freely diffuse across the cell membrane and increase in concentration in proportion to cell density. A cognate LuxR-like protein is responsible for recognition of the AHL and when bound to the AHL, LuxR-like protein binds to specific promoter DNA elements and activates transcription of target genes (Figure 1). The biochemical mechanism of action of the LuxI/LuxR pairs is conserved. The LuxI-like enzymes produce a specific AHL by coupling the acyl-side chain of a specific acyl-acyl carrier protein (acyl-ACP) from the fatty acid biosynthetic machinery to the homocysteine moiety of S-adenosylmethionine (SAM). This intermediate lactonizes to form acyl-HSL, releasing methylthioadenosine [28,29]. There are hundreds of Gram-negative bacteria identified to use LuxI/LuxR-type quorum sensing to control a wide range of cellular processes. Each species produces a unique AHL or a unique combination of AHL and, as a result, only the members of the same species recognize and respond to its own signal molecule [7,8,25,28]. Many other examples of Gram-negative circuits exist that utilize a LuxI/LuxR-type quorum sensing mechanism onto which additional regulatory factors have been layered [7–9,25–30].

Bottom Line: Many bacteria are known to regulate their cooperative activities and physiological processes through a mechanism called quorum sensing (QS), in which bacterial cells communicate with each other by releasing, sensing and responding to small diffusible signal molecules.The ability of bacteria to communicate and behave as a group for social interactions like a multi-cellular organism has provided significant benefits to bacteria in host colonization, formation of biofilms, defense against competitors, and adaptation to changing environments.Therefore, understanding the molecular details of quorum sensing mechanisms and their controlled social activities may open a new avenue for controlling bacterial infections.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada. yung-hua.li@dal.ca

ABSTRACT
Many bacteria are known to regulate their cooperative activities and physiological processes through a mechanism called quorum sensing (QS), in which bacterial cells communicate with each other by releasing, sensing and responding to small diffusible signal molecules. The ability of bacteria to communicate and behave as a group for social interactions like a multi-cellular organism has provided significant benefits to bacteria in host colonization, formation of biofilms, defense against competitors, and adaptation to changing environments. Importantly, many QS-controlled activities have been involved in the virulence and pathogenic potential of bacteria. Therefore, understanding the molecular details of quorum sensing mechanisms and their controlled social activities may open a new avenue for controlling bacterial infections.

Show MeSH
Related in: MedlinePlus