Quorum Sensing - Science topic
A phenomenon where microorganisms communicate and coordinate their behavior by the accumulation of signaling molecules. A reaction occurs when a substance accumulates to a sufficient concentration. This is most commonly seen in bacteria.
Questions related to Quorum Sensing
If the compound shows growth inhibition of C. violaceum, can I still proceed to determine the anti-quorum sensing effects? How can I quantify the production of violacein production?
I would like to know if there are any commercially available rapid detection kits for quorum-sensing N-acyl homoserine lactone (AHLs). Would like a recommendation of a product that is commerically available with a relatively high degree of accuracy. Thanks.
I want to find a quorum sensing inhibitor from plant extracts.
Klebsiella pneumoniae, Moraxella catarrhalis, Staphylococcus aureus, and Streptococcus pneumoniae.
I looked for these strains available for purchase;
Chromobacteirum violaceum NCTC13278 (CV026)
Vibrio campbellii ATCC BAA-1116, 1117, 1118 (BB-120, 170, 886)
Are these strains commonly used?
Looking at the various CoV genomes, there are peptides/small proteins, aside from ORF1/2 on the genome, of which functions are unknown. These could circulate and in theory, once in abundance, induce allosteric changes in membrane bound proteins to induce viral shedding alike to bacteriophage Q-sense.
I am researching into how bacteria communicate.
What I've found is that they use quorum-sensing*, and electrical signals**.
I've also come across the ability to "speak and listen"***, but I wonder if there are more ways that they use.
Thank you for your answers!
The question might be a little bit stupid but I haven't found direct answer yet. Maybe anyone can explain it.
Why AHL molecules do not induct the activation of quorum-sensing genes inside the cells where they were synthesized? I mean, they might bound with transcription factors without leaving the cell, at least for gram-negative bacteria.
Quorum sensing, a type of bacterial interaction is found to be involved in the development of antibiotic resistance by the pathogenic microorganisms. I want to find if a non resistant bacteria can develop resistance to the same antibiotics while cultured together with the resistant microbes and does it involve the quorum sensing interactions between the two different species of microbes. Antibiotic resistance is found to take place by various ways like; efflux pump, chemical modifications and also by modification of drug targeting genes.
Therefore, i want to work on whether resistance could be developed by involvement of quorum sensing in the modification of drug targeting gene, for that I request to suggest protocols for the process of investigating inter-species quorum sensing involvement in drug resistance development by the modification of genes of bacteria targeted by the antibiotics.
Is there any explanation for this that why the same specie of bacteria is qourum sensing positive when it is isolated from clinical sample but when we isolate that specie from marine sediment, it is qourum sensing negative? what can be the possible reason?
Curious about what level of existence or non-existence (however one may qualify those two terms, or the two listed in the title ('living matter' or 'non-living matter') can collapse the wave function, so as to help research on understanding the "mesocopic" divide between the quantum (microscopic) and classical (macroscopic) realms of physics.
Here are some articles I've ran across/am using for my last paper in my undergraduate work:
Ethyl acetate is a commonly used solvent for extraction of AHLs. However when it comes to storing them, it is generally stored in acetonitrile after evaporating the solvent. Is it alright if the extracted AHLs are stored in the acidified ethyl acetate (0.2% glacial acetic acid)?
Theoretically, using a mutant strain of V. harveyi which is only capable of producing AI-2, bioluminescence was induced upon addition of a compound. On the other hand, with wild-type V. harveyi, AI-2 synthase was downregulated. How was it possible?
As a chemist, I realy could not distenguish the diffrence between them. And also I wonder what the advantage of this knid of assay comparing to the classical MIC test.
RhlR is a quorum sensing regulator in Pseudomonas aeruginosa. There are so many LuxR type quorum regulators have been crystallized and structures available in PDB. I wondering why the crystal structure of RhlR is not available till date ?
Hello everybody, we are working on the eradication of Helicobacter pylori and inhibition of its biofilm. We are looking for the suggestions that what compounds would be better to use against H. pylori to inhibit the quorum sensing.
I am working on quorum quenching activity of quenching enzymes specifically produced by Gram negative bacteria against S. aureus quorum sensing activity. The only way i found for this is using a S. aureus 8325-4 (pSB2035) transformant strain. Please, anyone if knows a better alternative, share with me. Thanks
Hi, I'm looking for anyone or any institution that may possibly provide me Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1 strains to be used for a research on quorum sensing? And have it arranged to be shipped to the Philippines? Thanks a lot!
I need a help here. I am currently working on inhibition of quorum sensing in Chromobacterium violaceium MTCC 2656.but my culture doesnt produce the purple pigment I am worried if the addition of commercially available long chain AHL molecules will help . how i need to go about this as my main study is on the inhibition of the pigment. please share your valuable suggestions
Thank you in advance
My protein and inhibitors, give different trends in MST data. Fnorm either it is in upward trend or downward trend. What does that mean ? can we define the inhibition level or the pattern with this data ?
Quorum sensing- Signalling molecule- Homoserine lactones-Inhibitors.
I want to test whether the AI-2 produced by bacteria A impact the growth of bacteria B. I want to extract AI-2 but remove proteins, sugars and others from culture broth that might also stimulate bacterial growth. The extract does not need to be pure compound, but it is better to remove proteins and sugars from broth.
I would appreciate your feedback on this issue. I am interested in evaluating the presence and subsequently quantifying AI-2 molecules in some bacterial cultures that I am working with. So, I would like to ask from those of you who are familiar with this topic to bring some insights of different approaches. For example, are there any culture media that I could use to detect it, is qPCR for LuxS enough, would HPLC work, or have you done any other techniques that gave reliable results?? Thank you in advance for your time!
Dear RG members
I like to discuss with you the recent advances on the quorum sensing and quorum quenching, specialy in Pseudomonas species.
Thanks for the discussion
Are there universal primers for the amplification of LuxI synthase gene homologues? I'm trying to check if my isolates carry a homologous LuxI synthase gene.
Any suggestions? Thanks!
Can we consider quorum-sensing regulation in bacteria as epigenetic regulation in eukaryotic cells ?
As part of a chemical ecology course, students are required to write a hypothetical research plan for any chemical ecological topic. I have chosen the topic of Characterization of Legume-Exuded Quorum Sensing Mimics on Nitrogen-Fixing Bacteria. Part of this research would involve the characterization of these mimics but I lack knowledge in this field. Currently I have selected liquid-liquid extraction followed by lC-MS, is this a reasonable choice?
Hi colleagues. I have a technical question. In nowadays I'm working with Quorum sensing inhibition. I had results showing two zones around of paper disk: one growth inhibition zone (close to disk) and another without violacein expression but with bacterial growth. My doubt is if that inhibition of violacein expression is caused by bacterial low density or by real inhibition of Acyl homoserine lactones. Please I need some orientation about it. Thanks !!!
What is the simplest, quickest, and/or cheapest way of finding out whether a molecule is involved in a novel quorum sensing / cell-cell signaling / signal transduction pathway?
Most literature explains assays that build on systems that have already been established, involving AHLs, AI-2, DKPs, DSFs, HAQs, etc., but our suspected signal molecule is not similar to those. It might be involved in cessation of cell growth, and we sort of have growth curves at different concentrations of the compound.
Outside of forward and reverse genetics, which would be especially difficult for our organism, an Archaeal methanogen, I’ve seen the most plausible options in this paper:
Affinity chromatography and photo-affinity labeling don’t seem simple or quick or cheap, though.
I’d appreciate any suggestions.
May I know the different types of signaling molecules in bacteria and fungi. Do different bacteria have different signaling molecules. Which are intracellular and intercellular molecules
I was doing N-Acyl homoserine lactone (AHL) extraction from bacteria using 0.1% acidfied ethyl acetate. Wondering does certain bacteria tolerance to this so that I might leave bacteria broth and acidfied ethyl acetate mixtures for extended time so that better yield of AHLs?
As a bachelor student, on my faculty we are allowed to run short student-led research projects. I decided to take on one such, and it will be concerned with quorum sensing in Gram-negative bacteria.
I have acquired a few biosensor strains that together ensure a rather good range of coverage of AHLs produced by the potential species studied. My only problem is, I can not decide on this species!
Ideally, I would like to characterize some species that is medically, agriculturally or ecologically relevant. But each and every bacterial species I have gone though has been already studied for their AHL composition.
Be it as it may, I am only a bachelor student and I might not have the bigger picture, nor the right search approach.
Considering all of the above, I decided to seek help in directing me to an interesting species. Alternatively, maybe there is another angle I fail to see under which I could utilize AHL-detecting biosensors in a scietifically relevant way? Maybe something easily doable with quorum quenching and biofilms? I only have three weeks of effective time, sadly.
Any input is appreciated!
Theoretically, the Quorum Sensing (QS) mechanism may be disrupted by any condition which prevents a faithful "count" of SC neighbors. This can be either due to reduced sensitivity of the SC itself, e.g., shortage of adequate receptors for environmental signals, or due to reduced "clarity" in the environment, concealing extracellular signals from the SC. The result in both cases is weakened ability to sense the "true" number of SCs in the micro-environment and, as a consequence, incessant proliferation and elusion of normal homeostatic tissue control. These two properties can be integrated into one parameter, the magnitude of intercellular communication sensed by a SC, which is expected to be the critical determinant of the tissue's steady-state production of end cells.
Agur Z, Kogan Y, Levi L, et al. Disruption of a Quorum Sensing mechanism triggers tumorigenesis: a simple discrete model corroborated by experiments in mammary cancer stem cells. Biology Direct. 2010;5:20. doi:10.1186/1745-6150-5-20.
we're performing a quorum sensing secretome characterization of a couple of bacterial strains, and we have met a few issues, which we cannot explain.
First, we had our Agrobacterium tumefaciens turn blue in an x-gal plate in absence of any AHLs added or an AHL-producer strain. We can be quite sure that there is no contamination as A. tumefaciens is grown in three antibiotics. The strain that we are using for detection, KYC55, has no HSL production machinery as the wildtype plasmid bearing traI HSL-synthase has been removed in this strain. So no mutations could have led to acquiring (back) production of AHL. So why do we see breakdown of X-gal in the apparent absence of AHLs? Are we missing something?
Second question is about the overlay assay. We got 18C TLC plates silica on glass, and when we poured the LB mixture with the sensor strain on the TLC with AHL bacterial extracts, the silica layer deattached from glass and started floating. We will only see tomorrow morning if this affected the assay anyhow, but we were wondering if this deattachment could be somehow avoided.
I am preparing to conduct a quorum sensing signal molecule assay on a bacterial species, where I would like to characterize the secretome of n-acyl-homoserine lactones (AHLs) that this species utilize.
I will be using RPC C-18 TLC assay. For this, I will have to synthesize AHL standards, which I will apply on the TLC next to the supernatant extract to be able to evaluate on the composition of AHL in the sample.
Since I will be synthesizing a bunch of these compounds C4-HSL, C6-HSL, C8-HSL, C-10 HSL, C12-GHSL their oxo-derivatives and other) and the starting materials are not so cheap, I was wondering, what is the minimal amount of those to successfully use on a TLC? Should be pretty small I assume?
I would like to know how expresses the Quorum sensing communication system in the response to physicochemical stress in lactic acid bacteria notament in Lactobacillus sp (if there are articles concerning this subject, please propose me)
I am planning to design a simulation for quorum sensing system and biofilm formation in S. Aureus. In order to do so, I would be needing kinetic data or affinity constant data for various protein-protein, protein-DNA or protein-substrate interactions. Naturally, I could try obtaining data for all individual proteins experimentally by myself, but if the data have been obtained already, I would rather not go through all that trouble. So if anyone knows about any database or repository which contains such data, I would be immensely grateful. Thank you! :)
Working concentration of AHL in minimal media is 2.5 mM and in water is 5 microM.
I am interested in quantifying quorum sensing in microbial biofilms. Is there any simple procedure to do so without using reporter bacteria
If anyone has the full text of this paper please do attach it as a file or send it as a mail (firstname.lastname@example.org).
Nonomura, H. (1974). Key for classification and identification of 458 species of the Streptomyces included in ISP. J Ferment Technol 52, 78–92.
I have a bacteriocin with known mechanism of antibacterial action (known receptor), can I check in silico for susceptible bacterial strains to this bacteriocin?
If yes, how would you propose to do this (in proteome, genome, which tools)? I would be even interested in longer and more formal cooperation. Maybe, you know any publications with in silico predictions of resistance/sensivity to antibacterial agents in different bacteria?
Any help would be appreciated,
Is it possible that A. tumefaciens A136 encounter some type of Mutation after serial culturing? if not then why it's not giving positive result even for positive control in Quorum sensing investigation?
please provide details of vendor or researchers from whom I can procure the toxins
I found the growth curves of S. aureus are different when some specific medicines was respectively added into the defined medium. Some have longer exponential phase, while others showed the shorter. Does anyone know about this? Is related to the Quorum Sensing System?
The initial data in my lab suggest that Compound X has an inhibitory role on the growth of E. coli in LB media, therefore, E. coli has developed a new class of transporters to translocate this compound to the outside of cytoplasm. Given that there is no previous data on the biological process that might be responsible for Compound X production, I am looking for possible methods to find out what substrate/process might produce it and what is the putative target of this compound in the cell.
Currently, I am using M9 media and replace the N-source with similar chemicals to Compound X. I am hoping that I will find a chemical that does not affect WT growth but inhibits the growth of the corresponding transporter deletion mutant.
Do you have any other suggestions how to further investigate this ides?
Does the AHL molecule in quorum sensing system could trigger the cell multiplication directly ? or the AHL molecule just act as signal within the bacteria population which not directly trigger the cell multiplication but just activated the virulence gene when reach the treshold?
I work at a project contain detecting AHLs from an activated sludge process (lab-scale) but despite all efforts I could not see any color on the TLC plates. My protocol is including:
1- Extract AHLs by ethylacetat. centrifuge the sample (10 ml), remove the supernatant, add 5 ml ethylacetat, vortex for 2 hours, centrifuge and take supernatant as AHLs solution, and then dried at 60 centigrade.
2- Add 100 microliters methanol and spot 3-5 microliters on TLC plate (Silica gel RP-18 Merck) and then develop in a glass tank with methanol/water (65:35), and then dried at room temperature.
3- The dried plates were overlaid with a culture of the indicator bacterium prepared as follows. For 20 × 20 cm plates, a 5-ml overnight culture of NT1(pDCI41E33) was used to inoculate 50 ml of LB and the new culture was grown 3-4 hours. The entire 55 ml of culture was added to 100 ml of the same medium containing 1 g of melted agar and 60 μg/ml 5-bromo-4-chloro-3-indolyl β-d-galactopyranoside (X-Gal) maintained. The culture was mixed thoroughly and immediately spread over the surface of the developed plate held in a Plexiglas jig designed to produce a uniform layer of agar about 3 mm thick. After the agar solidified, the coated plates were incubated at 28°C for 24 hr in a closed plastic container.
These were the method for detecting quorum sensing signals in detail in our laboratory.
I don't know what is the problem!!
Efflux Transporters used for certain compounds and efflux that compound from the cell to the media. But I am working on Triterpenoids, and their is no know Transporters to efflux that compound from the cell to the media. So I want to know is their any strategy if we can design the new transport protein that may work to Efflux the C30H50O from the Cell to the Media.
If we can predict that yes this specific transporter may Efflux the target compounds from the cell, because there are thousands of transport protein so we cant check all for just one compound as it is time consuming.
So if you dear can tell me some strategy .....
Thanks in Advance.
on the Effects of Antibiotics on Quorum Sensing in Pseudomonas aeruginosa paper by skindersoe et. al, they have used skimmed milk.
i am searching for a test for protease and elastase. im going to use a plant extract of tannins, is it possible that i use that method to?
how can that test (skim milk test) prove the effectivity of my sample? or how what is the manifestation of a postive result for this test?
Does anyone know where to get chromobacterium violacelium Cv026 for our quorum sensing research?
Did you ever research about a bacterium that has appearently almost never been studied in detail? Like for example Pseudomonas Mendocina S178S (JF513150). There is no trace of it in the literature!
What would you do if you wanted to know about its habitat, growth conditions, pathogenesis and competitive behaviour? Would you relate to literature about the whole species or do you think that would be inaccurate?
Thank you a lot!!
I was trying to make the aqueous stock solution of AHL (3-oxo c12 HSL). I dissolved 3-OXO- C12 HSL (20mg/ml) in ethyl acetate containing 0.01% glacial acetic acid and it was evaporated by passing Nitrogen gas. I got a white precipitate in the bottom of the tube which was insoluble when tried to dissolve in aqueous buffer.
Please suggest what else I can change in the protocol for making the aqueous stock.
We have tested a compound for its antibacterial activity. here we found 75% inhibition of growth but no MIC was found. Can anyone help me with answering this query?
I worked with P. aeruginosa PAO1 for quite a number of years already. First, in my lab at the California State Polytechnic University, I used an ATCC strain. Now I use a strain that Dr. Barbara Iglewski sent to a colleague.
In both cases, the strain produced a lot of mucus. Have you found mucoid variants of this strain? I know that hydrogen peroxide can induce a mucoid conversion of the strain but, do they convert spontaneoulsy to mucoid variants? I can attach pics if you would like to see them.
i am planning to work on providing a better biological solution for membrane fouling in membrane bio reactors. will introduction of genetically engineered organisms into MBR would be of any help? besides quorum quenching?
Thanks in advance.!
I am working on quorum quenching enzyme assay. My AHL stock is prepared in DMSO. In CV026 bioassay, my enzyme shows quorum quenching activity. For kinetic study, we are performing OPA based assay for detection of HSL. The read out of the OPA assay is very less. As the substrate concentration increases,the DMSO % goes upto 6-7 % in the final reaction mixture of the enzyme and the AHL (in DMSO). Is there any other way to prepare a stock solution with less DMSO without solubility issue ? Any advice on improving the OPA assay is requested.
S. aureus produces many carotenoids, how can one differentiate staphyloxanthin from other carotenoids? Is production of all these carotenoids under control of quorum sensing in this bacterium?
I am planning to establish the quorum sensing inhibition assay and i need tester strain wither c. violeceum or V. harvei. Is anyone can share the culture with me free of cost?
According to Quorum sensing controlled virulence factors , What is the regulatory mechanism of gelatinase enzyme in pseudomonas aeruginosa .
I am involved in an ongoing study looking at biofilm infection in patients. To my knowledge QSI are not yet used but may be advantageous in the fight against chronic bacterial infection. Any advice in this area gratefully received.
I am working on Quorum sensing activity.
Is there any possibilities that in Pseudomonas aeruginosa, pyocyanin activity decrease as crude plant extract concentration increases?
Rf values of TLC method for AHLs detection is mentioned in many paper, could we use them to Identify AHLs in our work?! (in the same condition)
When I was reading about quorum sensing mechanism, it seems to be that they are bacteriostatic. But, their are reports which are saying that QS agents can act as an antibacterial.
Can anybody suggest me the answer?
#essential oils #quorum sensing #quorum quennchig #microbiology #need for new protocol # recently published paper on similar idea
Examples such as those found in ants, bees, bacteria etc. point to the fact that collective decision making is also an important aspect of decentralized decision-making process. Most bacteria utilize quorum sensing to maintain population density, ants use it to find new nests, and recently, robots and self-organizing systems are using this signalling mechanism for decision-making. This forms the basis of Swarm intelligence. Incorporating some of these signalling aspects of SI into AI systems would make them more efficient and 'intelligent', do you agree?
I am trying to make a working concentration of 500 uM 3oC12HSL in LB (or any other aqueous medium for bacterial growth) by diluting my stock solution of 100 mM 3oC12HSL in DMF. Every time I add my stock solution to the medium the AHL starts to precipitate. I understand it is sparingly soluble in water. Is there any way to dissolve AHL into aqueous medium?
hi im currently conducting a research on inhibition of quorum sensing of pseudomonas aeruginosa, and one of its virulence is the proteolytic and elastolytic activity, how can i show the inhibition of these two using my sample which is a plant extract?