scholarly journals UJI IN VITRO BAKTERI ANTI QUORUM SENSING PENDEGRADASI ACYL HOMOSERINE LACTONE Aeromonas hydrophila

2017 ◽  
Vol 11 (3) ◽  
pp. 291
Author(s):  
Hessy Novita ◽  
Iman Rusmana ◽  
Munti Yuhana ◽  
Fachriyan Hasmi Pasaribu ◽  
Angela Mariana Lusiastuti
Keyword(s):  
Quorum Sensing ◽  
Fresh Water ◽  
Virulence Factors ◽  
Aeromonas Hydrophila ◽  
Homoserine Lactone ◽  
In Vitro Assay ◽  
Acyl Homoserine Lactone ◽  
Bacillus Sp ◽  
Vitro Assay

Anti quorum sensing (AQS) adalah proses inaktivasi atau degradasi molekul sinyal quorum sensing (QS) yaitu acyl homoserine lactone (AHL) tanpa memengaruhi pertumbuhan bakteri. Tujuan dari penelitian ini adalah untuk melakukan uji kultur bersama dan uji penghambatan faktor virulensi secara in vitro antara bakteri AQS dengan Aeromonas hydrophila sebagai patogen yang menyebabkan Motile Aeromonad Septicaemia (MAS) pada ikan air tawar. Hasil penelitian menunjukkan bahwa uji in vitro dengan kultur bersama antara bakteri AQS Bacillus sp. dan A. hydrophila tidak ada penghambatan pertumbuhan pada kedua bakteri, tetapi bakteri AQS dapat menghambat produksi faktor virulensi dari A. hydrophila yaitu protease dan hemolisin. AQS merupakan salah satu strategi yang potensial untuk diaplikasikan dalam pengendalian penyakit infeksius atau bakteri patogen resisten antibiotik pada budidaya ikan air tawar.Anti quorum sensing (AQS) was process of inactivation or degradation of Quorum sensing signal molecules of acyl homoserine lactone (AHL) without affecting growth of the bacteria. The aim of the reseach was to study in vitro assay of co-culture and inhibition of virulence factors between AQS bacteria which Aeromonas hydrophila as pathogen caused motile aeromonad septicaemia (MAS) in fresh water fish. The result showed that in vitro assay of co culture between AQS bacteria Bacillus sp. and A. hydrophila without inhibited of growth in both bacteria but bacteria AQS could suppressed production A. hydrophila virulence factors, protease, and hemolysin. The AQS is one of potential strategies to inhibit QS for application to control of infectious diseases or antibiotic resistant bacterial pathogens in fresh water aquaculture.

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 Recombinant N-acyl homoserine lactone-Lactonase AiiAQSI-1 Attenuates Aeromonas hydrophila Virulence Factors, Biofilm Formation and Reduces Mortality in Crucian Carp

Marine Drugs ◽  
2019 ◽  
Vol 17 (9) ◽  
pp. 499 ◽  
Author(s):  
Bao Zhang ◽  
Xiyi Zhuang ◽  
Liyun Guo ◽  
Robert J. C. McLean ◽  
Weihua Chu
Keyword(s):  
Virulence Factors ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Crucian Carp ◽  
Homoserine Lactone ◽  
In Vivo Studies ◽  
Acyl Homoserine Lactone ◽  
Signal Molecule ◽  
Promising Alternative ◽  
Feed Supplementation

Quorum quenching (QQ) is a promising alternative infection-control strategy to antibiotics that controls quorum-regulated virulence without killing the pathogens. Aeromonas hydrophila is an opportunistic gram-negative pathogen living in freshwater and marine environments. A. hydrophila possesses an N-acyl homoserine lactone (AHL)-based quorum-sensing (QS) system that regulates virulence, so quorum signal-inactivation (i.e., QQ) may represent a new way to combat A. hydrophila infection. In this study, an AHL lactonase gene, aiiA was cloned from Bacillus sp. strain QSI-1 and expressed in Escherichia coli strain BL21(DE3). The A. hydrophila hexanoyl homoserine lactone (C6-HSL) QS signal molecule was degraded by AiiAQSI-1, which resulted in a decrease of bacterial swimming motility, reduction of extracellular protease and hemolysin virulence factors, and inhibited the biofilm formation of A. hydrophila YJ-1 in a microtiter assay. In cell culture studies, AiiAQSI-1 decreased the ability of A. hydrophila adherence to and internalization by Epithelioma papulosum cyprini (EPC) cells. During in vivo studies, oral administration of AiiAQSI-1 via feed supplementation attenuated A. hydrophila infection in Crucian Carp. Results from this work indicate that feed supplementation with AiiAQSI-1 protein has potential to control A. hydrophila aquaculture disease via QQ.

scholarly journals Reversible Acyl-Homoserine Lactone Binding to Purified Vibrio fischeri LuxR Protein

2004 ◽  
Vol 186 (3) ◽  
pp. 631-637 ◽  
Author(s):  
M. L. Urbanowski ◽  
C. P. Lostroh ◽  
E. P. Greenberg
Keyword(s):  
Quorum Sensing ◽  
Promoter Region ◽  
Vibrio Fischeri ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
E Coli ◽  
High Affinity ◽  
Founding Member ◽  
Luxr Homolog

ABSTRACT The Vibrio fischeri LuxR protein is the founding member of a family of acyl-homoserine lactone-responsive quorum-sensing transcription factors. Previous genetic evidence indicates that in the presence of its quorum-sensing signal, N-(3-oxohexanoyl) homoserine lactone (3OC6-HSL), LuxR binds to lux box DNA within the promoter region of the luxI gene and activates transcription of the luxICDABEG luminescence operon. We have purified LuxR from recombinant Escherichia coli. Purified LuxR binds specifically and with high affinity to DNA containing a lux box. This binding requires addition of 3OC6-HSL to the assay reactions, presumably forming a LuxR-3OC6-HSL complex. When bound to the lux box at the luxI promoter in vitro, LuxR-3OC6-HSL enables E. coli RNA polymerase to initiate transcription from the luxI promoter. Unlike the well-characterized LuxR homolog TraR in complex with its signal (3-oxo-octanoyl-HSL), the LuxR-30C6-HSL complex can be reversibly inactivated by dilution, suggesting that 3OC6-HSL in the complex is not tightly bound and is in equilibrium with the bulk solvent. Thus, although LuxR and TraR both bind 3-oxoacyl-HSLs, the binding is qualitatively different. The differences have implications for the ways in which these proteins respond to decreases in signal concentrations or rapid drops in population density.

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.

Putative Virulence Factors of the Aeromonas spp. Isolated from Food and Environment in Abu Dhabi, United Arab Emirates

2006 ◽  
Vol 69 (7) ◽  
pp. 1713-1716 ◽  
Author(s):  
MOHAMMAD BASHIR AWAN ◽  
M. MAQBOOL AHMED ◽  
ABDUL BARI ◽  
KAREL KROVACEK
Keyword(s):  
United Arab Emirates ◽  
Virulence Factors ◽  
In Vitro Assay ◽  
Food Sources ◽  
Abu Dhabi ◽  
Virulence Determinants ◽  
Vitro Assay

Thirty randomly selected Aeromonas isolates from food and the environment in Abu Dhabi, United Arab Emirates, were characterized for putative virulence determinants, such as production of cytotoxin, cytotonic toxin, and hemolysin and their capacity to adhere to and invade Henle 407 cells in vitro. Seventy percent of the tested isolates were cytotoxin producers, and 80% were hemolytic. Cytotoxin was produced by 6 of 7 A. hydrophila strains, 6 of 13 A. caviae strains, and 6 of 7 A. veronii bv. sobria strains, mostly from food sources. A. schubertii, A. jandaei, and A. trota also produced both cytotoxin and hemolysin. All of the 30 isolates tested adhered to Henle 407 cells, but none were able to invade the cells, as determined with the in vitro assay. However, no significant correlation of the presence of these putative virulence factors was found among these aeromonad food isolates.

scholarly journals Efficacy of Liposomal Bismuth-Ethanedithiol-Loaded Tobramycin after Intratracheal Administration in Rats with Pulmonary Pseudomonas aeruginosa Infection

2012 ◽  
Vol 57 (1) ◽  
pp. 569-578 ◽  
Author(s):  
Moayad Alhariri ◽  
Abdelwahab Omri
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Homoserine Lactone ◽  
Protease Production ◽  
Signal Molecules ◽  
Acyl Homoserine Lactone ◽  
Signal Molecule ◽  
Intratracheal Administration ◽  
Content Type

ABSTRACTWe sought to investigate alterations in quorum-sensing signal moleculeN-acyl homoserine lactone secretion and in the release ofPseudomonas aeruginosavirulence factors, as well as thein vivoantimicrobial activity of bismuth-ethanedithiol incorporated into a liposome-loaded tobramycin formulation (LipoBiEDT-TOB) administered to rats chronically infected withP. aeruginosa. The quorum-sensing signal moleculeN-acyl homoserine lactone was monitored by using a biosensor organism.P. aeruginosavirulence factors were assessed spectrophotometrically. An agar beads model of chronicPseudomonaslung infection in rats was used to evaluate the efficacy of the liposomal formulation in the reduction of bacterial count. The levels of active tobramycin in the lungs and the kidneys were evaluated by microbiological assay. LipoBiEDT-TOB was effective in disrupting both quorum-sensing signal moleculesN-3-oxo-dodeccanoylhomoserine lactone andN-butanoylhomoserine lactone, as well as significantly (P< 0.05) reducing lipase, chitinase, and protease production. At 24 h after 3 treatments, the CFU counts in lungs of animals treated with LipoBiEDT-TOB were of 3 log10CFU/lung, comparated to 7.4 and 4.7 log10CFU/lung, respectively, in untreated lungs and in lungs treated with free antibiotic. The antibiotic concentration after the last dose of LipoBiEDT-TOB was 25.1 μg/lung, while no tobramycin was detected in the kidneys. As for the free antibiotic, we found 6.5 μg/kidney but could not detect any tobramycin in the lungs. Taken together, LipoBiEDT-TOB reduced the production of quorum-sensing molecules and virulence factors and could highly improve the management of chronic pulmonary infection in cystic fibrosis patients.

Evidence of quorum sensing in the rumen ecosystem: detection of N-acyl homoserine lactone autoinducers in ruminal contents

2002 ◽  
Vol 48 (4) ◽  
pp. 374-378 ◽  
Author(s):  
D L Erickson ◽  
V L Nsereko ◽  
D P Morgavi ◽  
L B Selinger ◽  
L M Rode ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Sensing Systems ◽  
Pure Cultures ◽  
Representative Selection ◽  
Great Complexity ◽  
Anaerobic Environment ◽  
Selection Of

Acyl-homoserine lactone (AHL) based quorum-sensing systems are widespread among gram-negative bacteria, particularly in association with plants and animals. As yet, there have been no reports of AHL signaling in the anaerobic rumen environment, an ecosystem of great complexity in which cell-cell signaling is likely to occur. We detected multiple AHL autoinducers in the rumen contents of 6 out of 8 cattle fed a representative selection of diets. The signals were not associated with feed. Surprisingly, no pure cultures produced AHLs in vitro when grown under the laboratory conditions we tested. Our observations suggest that either (a) a factor specific to the rumen ecosystem is required for the rumen isolates we tested to produce AHLs or (b) a strain (or strains) that we were not able to culture but which grows to a high cell density in the rumen produces the AHLs we detected.Key words: quorum sensing, rumen, acyl-homoserine lactone, anaerobic environment, bacteria, cattle.

scholarly journals Determination of quorum sensing system via biosensor strains and virulence factors in fish pathogen Aeromonas hydrophila

2020 ◽  
Vol 37 (1) ◽  
pp. 29-36
Author(s):  
Nurdan Filik ◽  
Ayşegül Kubilay
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Aeromonas Hydrophila ◽  
Homoserine Lactone ◽  
Signaling Molecules ◽  
Signal Molecules ◽  
Signaling Molecule ◽  
Sensing System ◽  
Quorum Sensing System

Quorum Sensing is a system that produces critical virulence factors, virulent get bacteria and manages the disease as a result, and when they realize that the bacteria reach the majority they want by enabling them to communicate with the signal molecules themselves. In this study, Quorum Sensing system of Aeromonas hydrophila (2 strains) which is the causative agent of fish infection Motile Aeromonas Septicemia (MAS) disease was studied. In the strains, primarily the production of N-butanoyl-L-homoserine lactone (BHL) and N-(3-octododecanoyl)-L-homoserine lactone (OdDHL) signaling molecules was investigated via Chromobacterium violaceum CV026 and Agrobacterium tumafeciens NT1 biosensor strains. A. hydrophila produced BHL signaling molecule in assay committed using C. violaceum CV026 strain, producing OdDHL signaling molecule in assay committed using A. tumefaciens NT1 strain. A. hydrophila was investigated as phenotypically by the detection of BHL and OdDHL signaling molecules and in the presence of virulence factors controlled by quorum sensing system such as ramnolipid, elastase, protease, amylase, hemolysis production dependent on these molecules. The ramnolipid, protease, amylase and hemolysis activities of A. hydrophila strains were found to be positive. A. hydrophila has less elastase activity than Pseudomonas aeruginosa PAO1 control strain. Research has emphasizing A. hydrophila strains are within a population and that they have a of quorum sensing system, shown that they act collectively that determined they produces dangerous virulence factors that cause disease in fish.

Sign in / Sign up

Export Citation Format

Share Document