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

RSC Advances ◽  
2016 ◽  
Vol 6 (14) ◽  
pp. 11128-11139 ◽  
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.

Biofilm Formation, Communication and Interactions of Mesophilic Leaching Bacteria during Pyrite Oxidation

2013 ◽  
Vol 825 ◽  
pp. 107-110
Author(s):  
Sören Bellenberg ◽  
Robert Barthen ◽  
Mario Vera ◽  
Nicolas Guiliani ◽  
Wolfgang Sand
Keyword(s):  
Quorum Sensing ◽  
Acidithiobacillus Ferrooxidans ◽  
Biofilm Formation ◽  
Pyrite Oxidation ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Mixed Cultures ◽  
Acyl Homoserine Lactone ◽  
Leaching Bacteria ◽  
Leaching Efficiency

A functional luxIR-type Quorum Sensing (QS) system is present in Acidithiobacillus ferrooxidans. However, cell-cell communication among various acidophilic chemolithoautotrophs growing on pyrite has not been studied in detail. These aspects are the scope of this study with emphasis on the effects exerted by the N-acyl-homoserine lactone (AHL) type signaling molecules which are produced by Acidithiobacillus ferrooxidans. Their effects on attachment and leaching efficiency by other leaching bacteria, such as Acidithiobacillus ferrivorans, Acidiferrobacter spp. SPIII/3 and Leptospirillum ferrooxidans in pure and mixed cultures growing on pyrite is shown.

Influence of Glucose Concentrations on Biofilm Formation, Motility, Exoprotease Production, and Quorum Sensing in Aeromonas hydrophila

2013 ◽  
Vol 76 (2) ◽  
pp. 239-247 ◽  
Author(s):  
IQBAL KABIR JAHID ◽  
NA-YOUNG LEE ◽  
ANNA KIM ◽  
SANG-DO HA
Keyword(s):  
Quorum Sensing ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Homoserine Lactone ◽  
Protease Production ◽  
Acyl Homoserine Lactone ◽  
Human Pathogen ◽  
Initial Biofilm ◽  
Motility Inhibition

Aeromonas hydrophila recently has received increased attention because it is opportunistic and a primary human pathogen. A. hydrophila biofilm formation and its control are a major concern for food safety because biofilms are related to virulence. Therefore, we investigated biofilm formation, motility inhibition, quorum sensing, and exoprotease production of this opportunistic pathogen in response to various glucose concentrations from 0.05 to 2.5% (wt/vol). More than 0.05% glucose significantly impaired (P < 0.05) quorum sensing, biofilm formation, protease production, and swarming and swimming motility, whereas bacteria treated with 0.05% glucose had activity similar to that of the control (0% glucose). A stage shift biofilm assay revealed that the addition of glucose (2.5%) inhibited initial biofilm formation but not later stages. However, addition of quorum sensing molecules N-3-butanoyl-DL-homoserine lactone and N-3-hexanoyl homoserine lactone partially restored protease production, indicating that quorum sensing is controlled by glucose concentrations. Thus, glucose present in food or added as a preservative could regulate acyl-homoserine lactone quorum sensing molecules, which mediate biofilm formation and virulence in A. hydrophila.

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

2006 ◽  
Vol 72 (11) ◽  
pp. 7294-7300 ◽  
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.

Isolation of Biofilm-Forming Bacteria from the Secondary Effluent of the Wastewater Treatment Plant and its Ability to Produce N-Acylhomoserine Lactone as Quorum Sensing Signal

2017 ◽  
Vol 863 ◽  
pp. 135-140 ◽  
Author(s):  
Eri Nasuno ◽  
Yuto Abe ◽  
Ken-ichi Iimura ◽  
Masaki Ohno ◽  
Tetsuji Okuda ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Quorum Sensing ◽  
Wastewater Treatment Plant ◽  
Biofilm Formation ◽  
Communication Systems ◽  
Treatment Plant ◽  
Homoserine Lactone ◽  
Side Chain ◽  
Secondary Effluent ◽  
Acyl Side Chain

Bacterial quorum sensing (QS) is one of the cell-to-cell communication systems. N-Acyl-homoserine lactones (AHLs) are the most common QS signals and responsible for biofilm formation in gram-negative bacteria. Inactivation of QS, also referred to as quorum quenching, has been regarded as a popular strategy to control membrane bioreactor (MBR) operations because biofouling in MBR wastewater treatment systems is often caused by biofilm formation. In the present study, 24 bacterial strains were isolated from the secondary effluent of a wastewater treatment plant and AHL productivity and biofilm formation were evaluated on 8 out of 24 isolates. The isolated 8 strains can produce AHLs that only possess a long (C8-C14) acyl side chain. The representative 3 strains were selected from these isolates based on the higher activity of biofilm formation. The AHL separation analysis with a thin layer chromatography clearly showed that N-octanoyl-L-homoserine lactone (C8-HSL) and N-hexanoyl-L-homoserine lactone (C6-HSL) existed in the secondary effluent sample, while no C6-HSL producing strain was isolated. C8-HSL was identified as the product of isolate No. 6. These results suggest that the secondary effluent probably contains various cell-to-cell signaling molecules derived not only from the inhabitants but also from the other microorganisms involved in the activated sludge for the biological pre-treatment. In this secondary effluent, AHL trapping techniques can be proposed as one of the acceptable strategies for the control of the QS systems because the remaining AHLs have relatively long acyl side chain and low concentrations.

scholarly journals Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
O. Lidor ◽  
A. Al-Quntar ◽  
E. C. Pesci ◽  
D. Steinberg
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
In Silico ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Site Directed Mutagenesis ◽  
Great Promise ◽  
Acyl Homoserine Lactone ◽  
Virulence Determinants

Abstract Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases.

scholarly journals The Transcriptional Activator rfiA Is Quorum-Sensing Regulated by Cotranscription with the luxI Homolog pcoI and Is Essential for Plant Virulence in Pseudomonas corrugata

2009 ◽  
Vol 22 (12) ◽  
pp. 1514-1522 ◽  
Author(s):  
Grazia Licciardello ◽  
Iris Bertani ◽  
Laura Steindler ◽  
Patrizia Bella ◽  
Vittorio Venturi ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Dna Binding Domain ◽  
Pseudomonas Corrugata ◽  
Gram Negative ◽  
Rnd Transporter ◽  
Pith Necrosis ◽  
Rhodotorula Pilimanae

The gram-negative phytopathogen Pseudomonas corrugata has an acyl-homoserine lactone (AHL) quorum-sensing (QS) system called PcoI/PcoR that is involved in virulence on tomato. This work identifies, downstream of pcoI, a gene designated rfiA, which we demonstrate is directly linked to QS by cotranscription with pcoI. The deduced RfiA protein contains a DNA-binding domain characteristic of the LuxR family but lacks the autoinducer-binding terminus characteristic of the QS LuxR-family proteins. We also identified, downstream of rfiA, an operon designated pcoABC, encoding for the three components of a tripartite resistance nodulation-cell-division (RND) transporter system. The expression of pcoABC is regulated by RfiA. We found that lipodepsipeptide (LDP) production is cell density dependent and mutants of pcoI, pcoR, and rfiA are unable to inhibit the growth of the LDP-sensitive microorganisms Rhodotorula pilimanae and Bacillus megaterium. P. corrugata rfiA mutants were significantly reduced in their ability to cause necrosis development in tomato pith. In addition, it was established that PcoR in the absence of AHL also played a role in virulence on tomato. A model for the role of PcoI, PcoR, and RfiA in tomato pith necrosis is presented.

scholarly journals A Distinct QscR Regulon in the Pseudomonas aeruginosa Quorum-Sensing Circuit

2006 ◽  
Vol 188 (9) ◽  
pp. 3365-3370 ◽  
Author(s):  
Yannick Lequette ◽  
Joon-Hee Lee ◽  
Fouzia Ledgham ◽  
Andrée Lazdunski ◽  
E. Peter Greenberg
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Opportunistic Pathogen ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Signal Molecule ◽  
Control Of Gene Expression ◽  
Signaling Systems ◽  
Sensing Systems

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa possesses two complete acyl-homoserine lactone (acyl-HSL) signaling systems. One system consists of LasI and LasR, which generate a 3-oxododecanoyl-homoserine lactone signal and respond to that signal, respectively. The other system is RhlI and RhlR, which generate butanoyl-homoserine lactone and respond to butanoyl-homoserine lactone, respectively. These quorum-sensing systems control hundreds of genes. There is also an orphan LasR-RhlR homolog, QscR, for which there is no cognate acyl-HSL synthetic enzyme. We previously reported that a qscR mutant is hypervirulent and showed that QscR transiently represses a few quorum-sensing-controlled genes. To better understand the role of QscR in P. aeruginosa gene regulation and to better understand the relationship between QscR, LasR, and RhlR control of gene expression, we used transcription profiling to identify a QscR-dependent regulon. Our analysis revealed that QscR activates some genes and represses others. Some of the repressed genes are not regulated by the LasR-I or RhlR-I systems, while others are. The LasI-generated 3-oxododecanoyl-homoserine lactone serves as a signal molecule for QscR. Thus, QscR appears to be an integral component of the P. aeruginosa quorum-sensing circuitry. QscR uses the LasI-generated acyl-homoserine lactone signal and controls a specific regulon that overlaps with the already overlapping LasR- and RhlR-dependent regulons.

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