Pseudomonas aeruginosa - Science topic

Hi everyone,

I am currently working on expressing a His-tagged protein of interest using a pHERD20T vector. I have successfully cloned my gene into the vector and am now attempting to electroporate Pseudomonas aeruginosa PAO1K with this construct. However, I am encountering difficulties in obtaining single colonies.

Here are the details of my experiment:

I prepared the antibiotic carbenicillin(200mg/ml) by dissolving the 2g of carbenicillin powder in sterile Milli-Q water, vortexing to dissolve completely and then adding milliQ to achieve a final volume of 10ml. This was followed by filter sterilizing the solution using a 0.22µm filter, aliquoting it and storing at -20°C. Therefore, I don't think I made any mistakes in preparing the antibiotic.

Despite trying different plasmid concentrations and volumes, I am unable to isolate single colonies. A colleague successfully performed electroporation with 100 ng of this plasmid in the past, so I am unsure if my plasmid concentration is too high or if there is another issue at play.

Has anyone experienced similar problems with this plasmid or have suggestions on how to improve transformation efficiency? Any insights or recommendations would be greatly appreciated.

Thank you!

I have recently isolated  presumptive pseudomonas aeruginosa from a pool water sample using membrane filtration on Pseudomonas CN agar. This was set up to be confirmed using CMA agar and nutrient agar. Results came back were oxidase positive, casein hydrolysis positive and colonies appeared pigmented. However no fluorescence was observed under UV light.

I was just wondering if without performing further tests would anyone would say this was confirmed as pseudomonas aeruginosa or is fluorescence a requirement?

Thanks

I am currently engaged in research pertaining to multidrug-resistant bacteria, including but not limited to Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli, and Bacillus cereus. My objective is to identify the three least efficacious antibiotics against these strains and, more broadly, to ascertain their general resistance patterns.

Hello, I am researching the resistance mechanisms in Pseudomonas aeruginosa and I would like to know if there are other methods, aside from qPCR or RT-PCR, to determine the expression of RND efflux pumps (Mex family). Do you have any experience using spot blot for this purpose?

During submission of sequences of 16 S rRNA partial sequence of Pseudomonas aeruginosa isolates in the NCBI, I have mentioned the name of organism as Pseudomonas aeruginosa at the beginning but near the end step I have also choose uncultured pseudomonas sp. by mistake and sequences are released. but all the isolates should be 16 S rRNA partial sequence of Pseudomonas aeruginosa strains instead of uncultured Pseudomonas sp. How this problem will be solved

I work in a very resource-limited microbiology laboratory. Recently, we have observed what appears to be a plaque-forming bacteriophage in a Pseudomonas aeruginosa culture. Are there low-cost methodologies for the isolation of this type of bacteriophages?

If the percentage of medium of dilution of peptide (like sterile water) is 5% to 10 %. Will it affect Pseudomonas aeruginosa bacterial growth?

While doing AST for Pseudomonas aeruginosa, after incubation, no zone of inhibition observed in the plate near the well. wells surrounded by bacterial growth, when the same plate observed under UV light, large zone of clearance was recorded. If, zone is showing absence of pyocin pigment production, how to interpret this result? whether take it as inhibited or not inhibited?

Hello, I am trying to fix Pseudomonas aeruginosa PAO1 cells with 4% formaldehyde for 20-30 minutes (on ice and in the dark) for fluorescent microscopy. I am attempting to stain the DNA and outer membrane, but have not been successful with this fixation method. The dyes give weak signals and appear to be exported out, suggesting the bacteria are not completely fixed with formaldehyde. Does anyone have a reliable protocol for PAO1 fixation, including concentration, time, quenching, etc.? Any help would be greatly appreciated.

Can the pACYC177 plasmid be used for transformation and gene complementation in Pseudomonas aeruginosa?

Hi everyone. I need to do a lot of colony counting tomorrow and when I was doing it today I’ve noticed that most of the colonies are too transparent - I have to shine bright light on them all the time in order to see something and I might’ve skipped tons of them. I left them for one more night of incubation at 37C and hopefully it gets better, but I am not completely sure about it.

Has anyone ever encountered an issue like this? I’m growing them on LB agar and maybe that’s the reason, but re-plating them is not an option at the moment.

Any tips on light source? Maybe I need to illuminate them with UV to visualise the pigment but I’m afraid of killing them and I know that very specific conditions are required for them to start making pigment.

Thank you!

Hi

I am trying to revive Pseudomonas aeruginosa from frozen glycerol stock and also from cryobeads. But there was no bacterial growth. I used nutrient agar, tryptone soy agar to streak on. Also I added glycerol stock to nutrient broth and tryptone soy broth but there was no growth.

I would appreciate your guidance.

Thank you

Hi!

I left some petri dishes with Pseudomonas aeruginosa cultivated in MHI in the fridge (8°C) during some time off, and when I came back, it was like this. This is just one plate out of many, and it was sealed. I'm attaching photos of the plate, including an amplified view with 2x magnification. I did some research and it could be crystals, but I have never seen anything like this before. If somene knows something, please let me know. Thank you in advance.

As a new microbiologist, I am currently working in a non-sterile production pharmaceutical factory where I take pure water samples from 13 points, fill 100 ml of pure water into 3 sample containers from each point, process them by membrane filtration and add them to TSA, SDA and MCA media to examine TAMC, TYMC and E.coli.

In the pharmacopoeia, only R2A agar is recommended for this work, but there are P.aeruginosa, S.aureus, E.coli and Bacillus subtilis bacteria other than TAMC and TYMC that I should look for in pure water. I use 39 petri and sample containers for 13 points and 3 samples each time, is this too much? I do not know what I am missing or unnecessary, I am still researching, what do you suggest me to do? Is there a method that you can give for sure and that works?

Hi, I realized an ELISA to evaluate interactions of Lipopolysaccharide of a specific strain of Pseudomonas aeruginosa and SARS-COV-2 Spike Protein. I use like blank a well witout LPS to coat it, I continue with the other steps: addition of blocking solution, spike protein, anti IgG horseradish peroxidase, TMB substrate and stop solution. But in this well, color is produced.

I don't Know, what is my error.

Can you help me, please?

Sincerely

Lucy Villafañe

Hello everyone

Here, I mean there is a high level of familiarity between VIM-1 and VIM-2 and I'm not sure if I can detect these two genes and distinguish them in Pseudomonas aeruginosa isolates by PCR.

I have blasted some primers—from articles—for these genes in NCBI and for example, I saw a primer pair in 80% of cases bonded to VIM-1, but unfortunately, the rest of the targets were sequences other than VIM-1, like VIM-2 and...

Do I need some other test like sequencing?

i am working on the determination of the synergism activity of the herbal and allopathic drug. firstly i tried to find out the zone of inhibition of individual drug having lower (25, 50, 100 ppm), middle (250, 500, 1000 ppm) and upper (2500, 5000, 10,000 ppm) concentration against s. aureus bacteria. but the expected result was not obtained in case of herbal drug. kindly provide the valuable suggestions for the same with references. I tried the same experiment against E. Coli and Pseudomonas Aeruginosa & the expected result was obtained in both cases. I am facing a problem only in case of S. Aureus. I also like to add that i repeated the experiment 9-10 times by maintaining aseptic condition and other cares to be taken while performing the experiment. Kindly give the solution for S. Aureus to get desired result. Thank You

Dear all -

we would like to produce and study biofilms of Pseudomonas aeruginosa. We are not well equipped, only a simple microscope. I wonder if it could be possible to make estimations on the drug (peptide) activity on the biofilm by using a plate reader to grow the biofilm and somehow use this setup to follow the live and dead cell staining?

Thank you very much for your response!

Have a nice day

Kornelius

Storage and maintenance of pathogens is a costly and time-consuming affair, the recent study indicated that most of the pathogenic bacteria can be stored for several months at room temperature in sterile tap water without any hustle.

Ref DOI: 10.13140/RG.2.2.34672.84480

The pseudomonas aeruginosa isolates in my mac plates are very dry. Can u plz suggest me a method to make them grow again normally. Will taking more culture from the old plate(dry) and streaking it in a new Mac plate help the bacteria to grow normally ?

If not then please suggest any other method

I have previously used LB broth medium in biofilm inhibition experiments against P. aeruginosa. However, I could not detect an effective biofilm formation in the negative control wells. Which medium would you recommend for sufficient biofilm formation in P. aeruginosa?

Thank you.

I am working on pseudomonas aeruginosa. My bacteria is susceptible to antibiotics, However will it be able to form biofilms?

is there a specific ratio to follow during the addition?

There are many complicated and detailed steps, devices like cold centrifuge, O.D measurement, silica gel, columns, HPLC, If possible please i need a short recap of the procedure and advices with Many Thanks to you

Ali

I work for a cosmetics lab in the microbiology department. Our lab is not accredited, but we do follow the International Standards (ISO).

One of the steps in these standards is to contaminate a cosmetic sample with a known strain (S. aureus, P. aeruginosa, and/or E. coli) in a known concentration and then plate the suspension. The media used is a non-selective media (TSA) and the plates after solidifying are incubated inverted. The entire procedure is done in a laminar airflow chamber. The strains used were purchased and then cryopreserved.

The issue is with the P. aeruginosa strain, regardless of the incorporation technique used it will form an aggregate of colonies. Furthermore, the stock strain (kept refrigerated at -5ºC) is changing color after 3 weeks and won't grow after streaking to new non-selective agar media, when most of our strains last at least 6 weeks.

What should we do to avoid the colonies from merging on the plate and is it normal for a strain to become invalid after that short of a period?

The first photo is of the colony aggregation issue and the second is the aspect of the stock strain after 3 weeks.

I am doing research on detecting and enumerating pseudomonas aeruginosa in drinking water using mpn and i would like to compare my findings with the standard quality of drinking water. But so far the only data i can find is on the standard level for e. coli and total coliform acceptable in drinking water. Is there an standard level for p. aeruginosa in drinking water? I remember reading somewhere that the acceptable amount was 2.2 mpn/100ml and below but i dont remember which standard data this was from.

I would like some information about the biofilms that are produced by Pseudomonas aeruginosa. Can the biofilms form on top of the liquid medium or do they bind to the bottom of the well. What are the best conditions to grow P. aeruginosa biofilms? In what medium and can they form in a anaerobic situation?

Thank you in advance

I’m doing qPCR for evaluating the resistance gene expression in pseudomonas aeruginosa, but melting peaks are not specific. I tried different annealing times and temperatures, different concentrations of cDNA and primer, and even used touchdown qPCR (55- 65 ). I tried with another set of primers but the results didn’t change. These new primers show good results with PAO1 (standard strain) but in the same condition, the clinical species melt peaks aren’t specific except for 16S rRNA which has a good peak in every condition. By the way, I confirmed the bacterial isolate by tox A and rpo D which are specific for the Pseudomonas aeruginosa. The primers are specific based on the blast results. (I used syberGreen)

I am trying to extract plasmids from Pseudomonas aeruginonas whose plasmid size is 200kb. The protocol I have can be used only for extracting plasmids that have a size of 10 to 15kb. So, how and under what conditions can I extract whole 200kb plasmids from Pseudomonas Aeruginosa? It means a lot to me.

I want to dissolve the PQS(The Pseudomonas aeruginosa 4-quinolone signal) in hydrophilic solutions like buffer or culture media, which surfactant is better? and also at what concentration?

is there any related work?

I'm looking to permeabilize the inner and outer membrane of Pseudomonas aeruginosa without lysing the cells in order to allow a hydrophobic molecule to enter the cytoplasm. The cells do not need to stay viable during the procedure, only intact and without denaturing or allowing cytoplasmic proteins to escape. So far i can only find procedures that permeabilize the outer membrane. Any known protocols out there? Thank you in advance!

I've cultured pseudomonas aeruginosa in a tryptic soy broth. After incubated overnight, I've found out there's a clumpy formation in it. Is it suppose to be like that, or it was contaminated?

Mn-doped nickel-cobalt ferrite doesn't show antibacterial activity? why? we are using Pseudomonas fluorescens, E.coli, Pseudomonas aeruginosa, staphylococuss aureus on the muller Hinton agar.There is an image

I am trying to detect LecA from a Pseudomonas aeruginosa PAO1 extract, for which I do a liquid culture overnight in LB broth (37oC, 200 rpm), harvest bacteria (10^8 cells) and lyse in presence of SDS buffer and DTT. SDS-PAGE and western blot labelling with appropriate antibodies is fine for the control (LecA) but I can't see any band in my sample. PCR experiments show the gene in my bacterial samples, however I am struggling a lot to find the lectin in the extracts. The obvious thought is to increase concentration of bacterial extract but it is already very concentrated.

Does anyone see any experimental error, or has any tip on the culture of this bacteria? Am I missing anything that prevents the lectin from being expressed? Please bear in mind, I am not a microbiologist so any detail could be enlightening for me.

Thanks!

I am culturing E. coli and Pseudomonas aeruginosa, both of which are randomly contaminated, after several times of bacterial subcultures, so what should I do now? give valuable answers and suggestions. Much appreciated.

I'm trying to get a labeled EPEC strain following a simple transformation protocol (25min in ice, 2min in 39°) but it doesn't work!

so if anyone works with EPEC and have recommendation about the best way to transform it, i'll be greatfull

PS: The protocol that i'm using works well with other strains like Pseudomonas aeruginosa

Hello! Can anyone help me please? I have sent purified bacterial sample of a bioluminescent bacteria isolated from a squid's eye to a commercial sequencing lab. The results came today, but the sequence similarity is showing 91% homology with Pseudomonas aeruginosa. The problem is we did morphological and biochemical tests in the lab on this bacterium and it does not look at all like Pseudomonas aeruginosa I don't know what went wrong. It is Gram-negative, pinpoint and extremely bioluminescent bacteria. I am confused. Is it a new bacterium or there is a technical mistake??

I need high density large volume inoculum for fermentation. Inoculum density of Pesudomonas aeroginosa is at OD₆₀₀=1.9, in 25 mL LB in 250 mL flask, while it is 1.6 in 50 mL medium in 250 mL flask. Then it drops down to OD₆₀₀=0.8 in 100 mL medium in 500 mL flask. I increased the no of loops as well, but same result was obtained. (37 degree Celsius/150 rpm)

According to EN 12353:2013 microorganisms used in a laboratory must be stored under -70ºC or lyophilized. I'm currently working in a cosmetics laboratory that uses microorganisms such as P. Aureginosa, C. Albicans, etc. in several microbiologic tests. We buy microorganism stocks from a supplier, which arrive lyophilized and need to be stored according to the laboratory practices implemented, however, we don't have a way to store these in temperatures under -20 °C, so is it possible to store microorganisms at this temperature?

Hello everyone,

I am culturing pseudomonas aeruginosa in BUP2 media using cysteine HCl. What is the difference it will cause if I use L-Cysteine Hydrochloride monohydrate instead of L-Cysteine Hydrochloride anhydrous. What is the meaning of L in cysteine.

Recently, I tried to evaluate the killing efficiency of one specific antibiotic on pseudomonas aeruginosa. when cells were cultured to the optical density of 0.6, 20-fold MIC was added. However, in the next 24 h, the broth keep turbidity. Nevertheless, the plate assay was performed to calculate the lived cells and we found the majority of bacterial cells were actually killed. To my best knowledge, the dead cell will experience autolysis and the broth will become clear and I have obtained the similar result before as well. so my question is why the turbidity of broth did not reduce although bacterial cells are dead?

I am given a task to extract rhamnolipid from P. aeruginosa. What are the ways or precautions can be done to produce high yield of rhamnolipid?

Hey everybody, I need help with a project I am working on with biofilm and Ti02 nanoparticle antimicrobial activity.

I need to know what are the culture requirments for Strep vridians, and what biofilm assay can I utilize to measure both strep viridians and pseudomonas aeruginosa.

please let me know! Thank you!

I am struggling to understand what might have caused the formations on these two slides:

Slide A: Gram stain of Pseudomonas aeruginosa.

Slide B: Gram stain of Staphylococcus epidermidis.

I have never come across anything like it before.

Can anyone shed some light?

Thanks in advance,

Seb

Methicillin-resistant Staphylococcus aureus (MRSA) ESBL-producing Enterobacteriaceae (extended-spectrum β-lactamases) Vancomycin-resistant Enterococcus (VRE) Multidrug-resistant Pseudomonas aeruginosa.

we have done a research on the effectiveness of sliver nanoparticle on MRSA.

do you have any recommendations on what is the best route to take I would love to hear your opinio.

I have conducted PCR on DNA extracted with boiling method for Pseudomonas aeruginosa and some of the samples had multiple bands. Also, in the same manner i have encountered the same problem with Klebsiella pneumoniae isolates in the detection of another gene. Moreover, I can't detect the exact problem?

Can anyone kindly provide guidance ?

I am planning on conducting P. aeruginosa conjugation using E. coli S17-1 lambda pir as donor strain.

I have also read some publications and studies that were using Pseudomonas Isolation Agar (PIA) to select against E. coli. But here instead i am going to use Simmons Citrate Agar as the media to screen the transconjugants against the E. coli. It is based on the fact that E. coli's growth is inhibited when cultured on SCA, and P. aeruginosa is not. Has anyone ever experienced using SCA in P. aeruginosa conjugation?

and is it possible to use SCA with antibiotic for better selection (such as 100 ng/ul gentamicin)?

Currently, I am struggling to verify the transformation of Pseudomonas aeruginosa with shuttle plasmids that I assembled in vitro and amplified in E. coli. Unfortunately, the colony-PCR experience in our lab is exclusively in E. coli, and while I try to adapt protocols which are recommended for P. aeruginosa, I can't get any amplification. At this point, and because other PCRs are running well, we think that we need a positive control for P. aeruginosa.  Maybe amplifying a gene-sequence located in the chromosome could be used as such?

Does anybody have any experience using a positive control for amplification from P. aeruginosa colonies?

Thanks in advance!

During screening of microbial extracts for antibacterial activity I keep seeing an unusual effect on the growth of P. aeruginosa (PA), which I hope you can see in the images attached. Basically I am doing disk diffusion assays, so plates are inoculated with bacterial solution matching 0.5 McFarland standard. Whenever I do this with PA I see what looks like viral plaques. I have tried preparing the inoculum using both the overnight growth and direct suspension methods, but still see the same effect. The same thing happens with two different strains of PA, and on two types of media (MHA and BHA). Interestingly, the technician in the lab has tried to replicate this several times without success.

Also, there seems to be a strange effect where there is a halo of these plaque looking things around some of the disks, yet the bacteria are growing within the zone.

If anyone has come across this before, or has any idea, I would love to hear from you!

A patient was diagnosed as having UTI as per the urine culture report. The organism was Pseudomonas Aeruginosa which was sensitive to Cefipime. However, the literature shows that only Injectable cefipime can be given for UTI with Pseudomonas infections and oral Cefipime would not be effective when the drugs are the same and only the routes of administration are different .

Hi all,

Considering that one has the whole genome sequence (annotated) of a bacterium and wants to know if it has the potential to cause human diseases, what steps would you recommend (insilico)?

I noticed that one of my novel species falls into the phylogenetic cluster of Pseudomonas aeruginosa and is closely related to P. alcaligenes (which was isolated from human blood samples and is also responsible for bioremediation purposes) based on genome tree.

Does this affiliation can be trusted with respect to the pathogenecity tendency?

Thanks,

Timsy

Pseudomonas aeruginosa forms biofilm on different surfaces viz., glass, polystyrene, steel, ceramic and rubber. How can we quantify if the surfaces are being corroded after biofilm formation?

My lab designed a qPCR assay for amplifying the denitrification gene nirS from DNA extracted from soil. The assay has worked perfectly in the past with almost perfect efficiency and gene copy number results. However, recently we noticed that the assay was underestimating by 2 log (Should be at least 10^5, but coming out as 10^3). This was noticed as the gene copy numbers of the external positive control, Pseudomonas aeruginosa, were 2 logs lower than they should be. We tested a number of things to explain this. We regrew and extracted fresh DNA from a new strain of P. aeruginosa, yet the results were the same. BSA was used in this assay, but was also found to not affect gene copy numbers to this extent. Standards and stocks were all re-quantified using Qubit. We are still unsure what is causing the underestimation and how we should to proceed. Does anyone have any suggestions for troubleshooting this issue? Or know of any published research that ran into similar issues? All suggestions are welcome, thank you.

How to differentiate Pseudomonas fluoresence and Pseudomonas aeruginosa based on morphological ,cultural and biochemical characteristics

I have the following strains of bacteria and have been advised to culture them on a mixture of MAC and Blood Agar. I want to know the ratios.

1. Klebsiella pneumoniae

2. Escherichia coli

3. Staphylococcus aureus

4. Enterococcus faecalis

5. Pseudomonas aeruginosa.

Thank You.

Hello,

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!

*: &

**: https://www.quantamagazine.org/bacteria-use-brainlike-bursts-of-electricity-to-communicate-20170905

***: https://www.cs.montana.edu/webworks/projects/stevesbook/contents/chapters/chapter001/section006/green/page003.html

i want to compare gene expression results of some resistance genes in Pseudomonas aeruginosa from clinical samples , to reference strain of Pseudomonas aeruginosa ( which is normally does not over express these genes ) , in order to see whether there is an over-expression in the clinical strain or not .

Q: what strain i should use ?

There are two virulence factors of Pseudomonas aeruginosa that I'm currently studying, LasA protease and LasB elastase. From what I gathered, I know that LasB has a role in promoting biofilm formation through rhamnolipid-mediated regulation. Does anyone know if LasA also plays a crucial role in biofilm formation of P. aeruginosa, either directly or indirectly?

I want to investigate role of complement antibodies (C1q, MBL, CL-11 etc) against Pseudomonas aeruginosa. For this research work i have to use BSA for blocking purpose but can i use skim milk instead of it?

I'm currently collecting references about staphylolytic assay to detect LasA protease activity and elastin congo red assay to detect LasB elastase activity in Pseudomonas aeruginosa, but from the references I've gathered so far, I can't understand why do we need to use different mediums to conduct each assay? For staphylolytic, the PA needs to be cultured in Luria-Bertani broth (a rich medium). While for elastin congo red assay, the PA needs to be cultured in AB medium (a minimal medium). Is there any specific reason behind this?

This is one of the references, but I got more/less the same method for all journals I've read

Hi everyone,

I'd like to transfer an integrative plasmid to P. aeruginosa PAO1 and the resistance marker is trimethoprim. Has anyone used that selection before in PAO1? I can't find much online about what concentration to use. Any help/literature is greatly appreciated! Thanks

Hello,

Please, i would like to know if on the king'B medium there is only Pseudomonas aeruginosa, P. fluorescens and P. putida which appear fluorescent ?

Thank you,

People who work with bacteria, I have been looking at literature and every time a photolysis experiment to thermally kill bacteria is done, the bacteria are spun down, the supernatant growth solution is discarded and the cells are re-dispersed in a buffer/ salt solution before they are incubated with nanomaterial or the drug. Subsequently the photolysis experiment is also carried out while the bacteria are in buffer.

Is there any specific reason for this? Would a photolysis experiment with bacteria still in the growth solution not work?

The choice of buffer/ salt solution also seems to vary a lot. Is the choice dependent on the strain of bacteria or more on the bacteria recognizing (targeting) molecule? For instance, in Nano Lett. 2008, 8, 1, 302-306 they dispersed Pseudomonas aeruginosa in a 0.85% sodium chloride solution and antibodies were used to target bacterial cells. While in , Pseudomonas aeruginosa and other bacterial strains were just washed with MilliQ water and phages were used as target agents.

Any help or insight in this regarded is highly appreciated.

My Question: Can I directly say that this soil bacterium is human pathogen? OR This bacterium holds potential for being human pathogen?

P.S: The bacterium was isolated from grassland soil to study their role in nitrogen cycle , more specifically, respiratory ammonifcation /Dissimilatory nitrate reduction/ denitrification.

Regards,

Timsy

These virulence factors allowing pathogenic bacteria to cause different illness such as pneumonia, burns infections and bacteremia. Any microorganism especially pathogenic bacteria can be a virulent when a single factor presented; sometimes the presence of various factors at the same time is required to decide the bacterial ability of causing infections

For writing grant proposal as a part of coursework, my objective is to find out methylation status of 3 genes in Pseudomonas aeruginosa and staphylococcus aureus

I have two strains from a single patient. Both have been confirmed as Ps. aeruginosa by PCR. One of them produces a dense brown pigment but the other produces no pigment....has anyone come across this before?

Thanks,

Bruno

Some clinical isolates of Pseudomonas aeruginosa exhibit resistance to IMP, MERO, TIC, TCC and PIP, high MIC to MERO and IMP tested to identify their resistance mechanism, were negative the MbL test and didn't show any difference in the MIC for MERO when tested in presence and abscence of the PAbN EPI (Efflux pimps Inhibitor)????

How could we caracterize their resistance machenism?

please i want this paper

I have seen the antibiofilm effect of a phytochemical. It disrupts EPS but I want to know the mechanism of that agent at the genetic and molecular level . What experiments should I employ?

Hi everyone,

I am working on rhamnolipid related virulence factors of Pseudomonas aeruginosa and I really need to know if the FliD mutants produce any rhamnolipid or not? Any related ınformatıon would be appreciated.

Thank you,

Regards

Sebnem Bukavaz

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 ?

Is E. coli an absolute negative for Sperbers Modified Agar?

In the paper, 'Molecular Characterization of Mineral Phosphate Solubilization In Serratia marcescens and Methylobacterium sp.' by A. Kumari, it's stated that E. coli lacks mineral phosphate solubilizing ability because it does not possess the PQQ cofactor.

However, when spotting both E. coli strains 51813 and 8739 (ATCC) onto Modified Sperber's Media (MSM), I found small clearing zones of the Tricalcium Phosphate after 48 hrs.

A colony of E. coli was spotted on each segment of the triplate and the plates were incubated for 48 - 72 hrs.

This same method was used with Pseudomonas aeruginosa as a positive control/reference and images of those plates are also attached.

In addition, Bromothymol Blue (BTB) was added to the MSM media to assist in visualizing the zones and the color change of media suggests the E. coli was fermenting the glucose within the media to produce acetic acid. Since one proposed method of microbial phosphate solubilization is through the secretion of organic acids, is it possible that this could explain the clearings observed?

Are there any other instances of E. coli strains exhibiting phosphate solubilizing activity? Or is there likely an error in my methods?

Modified Sperber's Media used:

For 1L of H20

10g Glucose, 0.5g Yeast Extract, 0.1g CaCl2, 0.25g MgSO4, 18g Agar

10% CaCl2 w/v @ 3ml & 10% K2HPO w/v @ 2ml/ 100ml was added to the media before pH adjustment & pouring.

The pH achieved was 7.114

Any assistance or guidance is appreciated!

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 have used LB broth and it is very clumpy.

the nanoparticles were purchased from sigma and they have a size range (35-50 nm). i tried to dissolve it in DMSO ( 5% of the nanoparticle solution) and i also tried to sonicate it for 30 minutes and they still do not work on pseudomonas aeruginosa ( control strain- ATCC 9027/12924). i tried the MIC and the disc diffusion methods