Role of capsular polysaccharide (CPS) in biofilm formation and regulation of CPS production by quorum-sensing inVibrio vulnificus

ABSTRACTStreptococcus pneumoniaeis the leading cause of death in children worldwide and forms highly organized biofilms in the nasopharynx, lungs, and middle ear mucosa. TheluxS-controlled quorum-sensing (QS) system has recently been implicated in virulence and persistence in the nasopharynx, but its role in biofilms has not been studied. Here we show that this QS system plays a major role in the control ofS. pneumoniaebiofilm formation. Our results demonstrate that theluxSgene is contained by invasive isolates and normal-flora strains in a region that contains genes involved in division and cell wall biosynthesis. TheluxSgene was maximally transcribed, as a monocistronic message, in the early mid-log phase of growth, and this coincides with the appearance of early biofilms. Demonstrating the role of the LuxS system in regulatingS. pneumoniaebiofilms, at 24 h postinoculation, two different D39ΔluxSmutants produced ∼80% less biofilm biomass than wild-type (WT) strain D39 did. Complementation of these strains withluxS, either in a plasmid or integrated as a single copy in the genome, restored their biofilm level to that of the WT. Moreover, a soluble factor secreted by WT strain D39 or purified AI-2 restored the biofilm phenotype of D39ΔluxS. Our results also demonstrate that during the early mid-log phase of growth, LuxS regulates the transcript levels oflytA, which encodes an autolysin previously implicated in biofilms, and also the transcript levels ofply, which encodes the pneumococcal pneumolysin. In conclusion, theluxS-controlled QS system is a key regulator of early biofilm formation byS. pneumoniaestrain D39.

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Role of Quorum Sensing and Antimicrobial Component Production by Serratia plymuthica in Formation of Biofilms, Including Mixed Biofilms with Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.01708-06 ◽

2006 ◽

Vol 72 (11) ◽

pp. 7294-7300 ◽

Cited By ~ 40

Author(s):

Pieter Moons ◽

Rob Van Houdt ◽

Abram Aertsen ◽

Kristof Vanoirbeek ◽

Yves Engelborghs ◽

...

Keyword(s):

Escherichia Coli ◽

Quorum Sensing ◽

Biofilm Formation ◽

Homoserine Lactone ◽

Broth Culture ◽

Confocal Laser ◽

Wild Type ◽

Serratia Plymuthica ◽

E Coli

ABSTRACT We have previously characterized the N-acyl-l-homoserine lactone-based quorum-sensing system of the biofilm isolate Serratia plymuthica RVH1. Here we investigated the role of quorum sensing and of quorum-sensing-dependent production of an antimicrobial compound (AC) on biofilm formation by RVH1 and on the cocultivation of RVH1 and Escherichia coli in planktonic cultures or in biofilms. Biofilm formation of S. plymuthica was not affected by the knockout of splI or splR, the S. plymuthica homologs of the luxI or luxR quorum-sensing gene, respectively, or by the knockout of AC production. E. coli grew well in mixed broth culture with RVH1 until the latter reached 8.5 to 9.5 log CFU/ml, after which the E. coli colony counts steeply declined. In comparison, only a very small decline occurred in cocultures with the S. plymuthica AC-deficient and splI mutants. Complementation with exogenous N-hexanoyl-l-homoserine lactone rescued the wild-type phenotype of the splI mutant. The splR knockout mutant also induced a steep decline of E. coli, consistent with its proposed function as a repressor of quorum-sensing-regulated genes. The numbers of E. coli in 3-day-old mixed biofilms followed a similar pattern, being higher with S. plymuthica deficient in SplI or AC production than with wild-type S. plymuthica, the splR mutant, or the splI mutant in the presence of N-hexanoyl-l-homoserine lactone. Confocal laser scanning microscopic analysis of mixed biofilms established with strains producing different fluorescent proteins showed that E. coli microcolonies were less developed in the presence of RVH1 than in the presence of the AC-deficient mutant.

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Biofilm formation of Pseudomonas putida IsoF: the role of quorum sensing as assessed by proteomics

Systematic and Applied Microbiology ◽

10.1016/j.syapm.2004.10.005 ◽

2005 ◽

Vol 28 (2) ◽

pp. 87-114 ◽

Cited By ~ 37

Author(s):

Catalina Arevalo-Ferro ◽

Gerold Reil ◽

Angelika Görg ◽

Leo Eberl ◽

Kathrin Riedel

Keyword(s):

Quorum Sensing ◽

Pseudomonas Putida ◽

Biofilm Formation

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The CpAL Quorum Sensing System Regulates Production of Hemolysins CPA and PFO To Build Clostridium perfringens Biofilms

Infection and Immunity ◽

10.1128/iai.00240-15 ◽

2015 ◽

Vol 83 (6) ◽

pp. 2430-2442 ◽

Cited By ~ 18

Author(s):

Jorge E. Vidal ◽

Joshua R. Shak ◽

Adrian Canizalez-Roman

Keyword(s):

Quorum Sensing ◽

Clostridium Perfringens ◽

Biofilm Formation ◽

Extracellular Dna ◽

Wild Type ◽

Content Type ◽

Type C ◽

Enteritis Necroticans ◽

Biofilm Structure

Clostridium perfringensstrains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by theC. perfringensAgr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. AlthoughC. perfringensstrains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrBmutant strains were not able to produce biofilms, a ΔluxSmutant produced wild-type levels. The transcript levels of CpAL-regulatedcpaandpfoAgenes, but notcpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpaand ΔpfoAmutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpbmade wild-type levels. Biofilm formation was restored in complemented Δcpa/cpaand ΔpfoA/pfoAstrains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation inC. perfringensby increasing levels of certain toxins required to build biofilms.

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Role of N-acyl-homoserine lactone (AHL) based quorum sensing on biofilm formation on packing media in wastewater treatment process

RSC Advances ◽

10.1039/c5ra23466b ◽

2016 ◽

Vol 6 (14) ◽

pp. 11128-11139 ◽

Cited By ~ 32

Author(s):

Huizhi Hu ◽

Junguo He ◽

Jian Liu ◽

Huarong Yu ◽

Jian Tang ◽

...

Keyword(s):

Wastewater Treatment ◽

Quorum Sensing ◽

Biofilm Formation ◽

Treatment Process ◽

Single Species ◽

Homoserine Lactone ◽

Acyl Homoserine Lactone ◽

Wastewater Treatment Process

Quorum sensing (QS) signaling has been extensively studied in granules and single species populations.

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Quorum sensing and biofilm formation in mycobacteria: Role of c-di-GMP and methods to study this second messenger

IUBMB Life ◽

10.1002/iub.1339 ◽

2014 ◽

Vol 66 (12) ◽

pp. 823-834 ◽

Cited By ~ 22

Author(s):

Indra Mani Sharma ◽

Anushya Petchiappan ◽

Dipankar Chatterji

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Second Messenger

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Enterococcus faecalisV583 LuxS/AI-2 system is devoid of role in intra-species quorum-sensing but contributes to virulence in aDrosophilahost model

10.1101/344176 ◽

2018 ◽

Author(s):

Frederic Gaspar ◽

Neuza Teixeira ◽

Natalia Montero ◽

Tamara Aleksandrzak-Piekarczyk ◽

Renata Matos ◽

...

Keyword(s):

Gene Expression ◽

Quorum Sensing ◽

Biofilm Formation ◽

Pathogenic Potential ◽

Functional Roles ◽

Injury Model ◽

Differential Gene ◽

Vancomycin Resistant ◽

Quorum Sensing Molecule

AbstractThe AI-2 i nterspecies quorum-sensing molecule is produced by the LuxS enzyme and has been ascribed a role in virulence in several bacteria. The nosocomial pathogenEnterococcus faecalisinhabits several different environments where multispecies communities are established. However, despite the presence of aluxSgene in this pathogen, its role inE. faecalispathogenesis has never been assessed. In the present work, we deleted theluxSgene from the vancomycin-resistant clinical isolateE. faecalisV583 and demonstrated the lack of AI-2 production by the mutant strain. Using microarrays and externally added (S)-4,5-dihydroxy-2,3-pentanedione we showed that AI-2 is not sensed byE. faecalisas a canonical quorum-sensing molecule and that theluxSmutation caused pleiotropic effects in gene expression, which could not be complemented by extracellularly added AI-2. These global differences in gene expression affected several gene functional roles, mainly those enrolled in metabolism and transport. Metabolic phenotypi ng of theluxSmutant, using Biolog plates, showed differences in utilization of galactose. AI-2 production by LuxS was shown to be irrelevant for some phenotypes related to the pathogenic potential ofE. faecalisnamely biofilm formation, adhesion to Caco-2 cells, resistance to oxidative stress and survival inside J-774 macrophages. However, theluxSmutant was attenuated when tested in theDrosophilaseptic injury model, as its deletion led to delayed fly death. Overall our findings show that differential gene expression related to theluxSmutation cannot be ascribed to quorum-sensing. Moreover, the role of LuxS appears to be limited to metabolism.

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A Constitutively Active Variant of the Quorum-Sensing Regulator LuxO Affects Protease Production and Biofilm Formation in Vibrio cholerae

Infection and Immunity ◽

10.1128/iai.71.5.2571-2576.2003 ◽

2003 ◽

Vol 71 (5) ◽

pp. 2571-2576 ◽

Cited By ~ 77

Author(s):

Russell E. Vance ◽

Jun Zhu ◽

John J. Mekalanos

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Biofilm Formation ◽

Protease Production ◽

Aquatic Habitats ◽

Wild Type ◽

Protease Deficient ◽

Active Variant ◽

Protease Expression

ABSTRACT Vibrio cholerae normally inhabits aquatic habitats but can cause a severe diarrheal illness in humans. Its arsenal of virulence factors includes a secreted hemagglutinin (HA) protease. An HA protease-deficient mutant of V. cholerae was isolated and designated E7946 mpc. E7946 mpc was found to contain a point mutation in the luxO quorum-sensing regulator. In accordance with this finding, E7946 mpc exhibits a defect in quorum sensing. The mutant luxO allele [luxO(Con)] produces a protein with a leucine-to-glutamine substitution at amino acid 104. Transfer of the luxO(Con) allele to an otherwise wild-type background was sufficient to eliminate HA protease expression; conversely, deletion of luxO(Con) from E7946 mpc restored protease activity. We demonstrate that LuxO(Con) constitutively represses the transcription of hapR, an essential positive regulator of HA protease. Interestingly, strains harboring luxO(Con) form enhanced biofilms, and enhanced biofilm formation does not appear to be dependent on reduced HA protease expression. Taken together, the results confirm the role of LuxO as a central “switch” that coordinately regulates virulence-related phenotypes such as protease production and biofilm formation.

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