Microbiology and Immunology

Dear all, I am a student looking for an internship in the UK, currently I am talking to New Castle and Glasgow university, both in the immunological field. Since I am not from the UK myself I have no idea if maybe one of these has a really good or bad reputation. If you know more about this, please let me know

Hi! I am doing an intracellular FACS staining and I was wondering if Caltag permeabilization buffer also permeabilizes the nucleus... Thanks!

Hi guys, I am following a protocol for the DNA extraction from Gram negative bacteria. I am completely new in this stuff.The protocol says to start from a bacterial suspension of approximately 109 CFUml . My question is : How can I determine and check if I have this concentration?with the spectrophotometer? if yes, how can I get the concentrationj from the absorbance? Thank you very much.

Hi all, I have a question about a calculation I am struggling to solve. I have two mix two different antibiotic solutions..one at 50mg/ml and the other one at 10mg/ml . The final solution of the mix of the two antibiotics should be at 10 mg/ml...How do I calculate the initial volumes to take from the two stock solutions to mix? Thank you in advance. Silvia

Hello everybody, I've started a software project called "dilutionMagic". It is a desktop serial dilution calculator optimized (for now) for serial dilutions on a 96-well plate. Currently it works on Windows. It can do custom dilution steps and non-equal sample volumes. The project is and will remain open source. The beta version is operational, but I need user feedback to make it better. Please download the program and try it out at URL removed per Rule 2.7. You can tell me what you think and what you would like to be improved or added, preferably through the forum Please help me make dilutionMagic a swiss army knife for serial dilution calculations. regards Peter

Hi all, do you know a protocol I can use to do PFGE on Klebsiella Pneumoniae? Thank you very much. Silvia

Hi all, just a quick question because I am new with laboratory stuff and calculations. If I have to prepare a stock solution of 10mg/ml of lysozyme, don't I need to know the molecular weight of lysozyme, do I? I just weight 10 mg and I dissolve them in 1 ml of water..right? Can I also weight 5 mg and dissolve it in 500 ul..it is the same, isnt'it (so that I don't waste it in case something goes wrong)? Thank you very much. Silvia

I think diabetes is very heritable. My grandma has type 2 diabetes at her 60s, and now my mother finds out she has it too ! My grandfather has no problem with his blood sugar level at all, so does my father. is it due to my mother's genetic reason that no matter how careful she deals with her food she still has diabetes ? if that is true, i will probably get it in future. what are the chances of me getting diabetes ? is it preventable ? thanks.

Hi all, I am new with Microbiology laboratory stuff and I am doing some MICs with microbroth dilution method. I have a problem with that because I obtain MIC values for my control strains higher than expected (2-3 fold higher) and I can't understand what does not work in my experiment. I thought that it could be a diminished antibiotic potency but the drug is not out of date. I thought that it could depend on the solvent I use to make the antibiotic dilutions..I am doing them in Iso Sensitest broth. The procedure I used so far for my MIC is always the same and it worked with antibiotics like Ampicillin and Meropenem. Now I changed antibiotic and I am using Amikacin an…

Hi all, please I really need your help. I am doing some MIC with Amikacin and the values I obtained so far for the reference controls are totally out of range and higher than expected. Can you tell me if the procedure I am following for the antibiotic diluition is correct? Just to be sure that it does not depend on me. I prepare an amikacin stock solution of 5 mg in 500 ul. I prepare my antibiotic dilutions that are in the range : 128-0.125 ug/ml. The final volume in each eppendorf (I have one for each antibiotic dilution) should be 1.4 ml and the dilution should be made two-fold . So what I do is to prepare the solution of antibiotic most concentrated (128 ug/ml…

I read this very interesting article today posted by the Baltimore Sun. The article describes the case of a Washington police officer who lost her sight to a condition diagnosed as optic neuritis. Amid her five year search for a cure, Ofc.Vanna Belton volunteered for an unconventional stem cell study, which she financed from her own resources for $20,000. The study involved injecting stem cells, removed from her hip bone, into her right retina and left optic nerve. Although her local doctors advised against this experimental pursuit, Belton was determined and now have partially restored vision. The doctor pursuing this study, Dr. Jeffrey N. Weiss, admittedly circumven…

There is solid factual claims for ultraviolet light to be germicidal, and industry devices providing such, at around ~250 nm wavelenght. Would the usually fluorescent tubes usually used for this have the same action if the light source is instead, LEDs ? (at the same wavelength) If the emmissive power of LEDs is inferior; would longer application time compensate to yield same results ?

Why are only Clostridium and Bacillus genus able to form endospores? or why aren't all gram negative and most gram positive able to do so ?

I was watching the movie '28 Days Later' the other day (no pun intended) and I couldn't help but wonder whether anything like the Rage Virus was possible even in theory. Now please don't think I'm an idiot for even asking this. I am a microbiology student and know full well that the behaviour of the virus in the movie is absolute nonsense; there is no way that any virus could not only enter the cell, but also replicate to such a massive extent as to cause any sort of disease over the course of ~10-20 seconds as portrayed in the film, even the fastest viruses know to man take at least an 20 minutes to replicate in their host. That part is just a bunch of Hollywood BS.…

Hi all, I am aware of the difference between a laminar flow hood and a biosafety cabinet and I am using these days the first one to pour agar into my plates. Even so, the laminar hood is always busy this period and I was wondering if in your opinion I can use also the biosafety cabinet for this activity. Thank you very much, Silvia

Hey all, have you ever done MIC with meropenem? which solvent did you use to dissolve it in order to prepare the antibiotic stock solution? I have a bottle of meropenem provided by "MELFORD" supplier and on the bottle the meropenem is reported to be soluble in 5% of monobasic potassium phosphate. Anyway I checked in internet and I found that meropenem is soluble in water. So what would you suggest to use ? and which concentration should I have for my stock? Can you also give me some info about the storage modalities?and how long can I keep my stock? I am not sure about that. Thank you in advance. Silvia

Hi all, I have a very stupid question. I have an overnight culture and I want to measure its absorbance at spectrophotometer. Since I want to adjust the density of the culture to a specific value of absorbance, I need to diluite or concentrate my samples with water depending on which absorbance value I get. My question is: do I need to change the cuvette everytime even if it is the same sample diluited or concentrated? If no, how do I wash the cuvette? I use the plastic cuvettes. Thanks in advance. Silvia

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Hi all, I am encountering difficulties trying to figure out some calculations I have to do in order to diluite (or concentrate) my 2 bacterial solutions for a MIC test. I should adjust the density of my overnight cultures with water to equal that of the 0.5 McFarland Standard, which is roughly equivalent to OD600 0.08-0.1 (107-108 cfu/ml). I diluted my original overnight cultures like this: 1900 ul of water and 100 ul of overnight culture (total: 2 ml) and I take 1 ml of this solution for the measurements at the spectrophotometer. One culture has an OD of 1.10, so I have to diluite it and the other 0.06 so I should concentrate it. My question is : how do I diluite t…

Hi all, I am new with experimental stuff in Microbiology. I need to do some MICs (first time I do it) and I am trying to read up a little bit. I saw that the first step to do is making antibiotic stock solutions. The protocols that I saw suggests to get the purity of the antibiotic and calculate the amount of it to be weighted with the following formula: volume x concentration/potency. My question is: how can I get the potency of antibiotic? and which volume is better to use? Any suggestion would be really appreciated. Thank you in advance, Silvia

Hi Everyone, I'd like do ADCC assays in rats, using rat serum. Does anybody have a protocol for this, or suggestions as where I can purchase kits to do these kinda experiments. Please let me know if you have any suggetions. Much appreciated.

Hi all, I need to make MIC with imipenem. We have the 500 mg/500 mg Imipenem/Cilastatin Powder for Solution for Infusion. My question is: how do I calculate the quantity of powder for the antibiotic stock solution?and the volume of this? I need to test 5 isolates of Klebsiella pneumoniae with broth microdiluiton. Since I need to use the Iso-Sensitest Broth to diluite my antibiotic , do I need to grow also my cells in this same broth overnight before doing the MIC? If I choose to use the agar dilution plate method, can I test different isolates of the same bacterium in the same diluited plate in your opinion? Sorry for my stupid questions but I am completely new in that. …

Hello, so what i've learnt so far is that engulfed antigen's peptide will be presented on the surface of antigen presenting cell with MHC class II, and CD4 T cell will see it and trigger humoral immune response. And for the MHC class I, the virally infected/intracellular peptide will be cut up by proteosome and sent to the surface for CD8 T cell to recognize. My lecturer said that if the peptide of the antigen is first-seen in this case, the CD8 T cell will not activate immediately, but it will signal the infected cell to go to lymph node where they can be cross presented. My question here is, will this happen to every first-seen peptide of an antigen? …

Hello Scientists. I am new to the forum. Although I come from somewhat of a scientific background in the past, I am not educated in biochemistry. At this point I would call myself a scientific researcher and independent student, not necessarily by choice, but out of necessity. Nevertheless, I've found this area profoundly interesting. Hoping your vast knowledge can help me find some answers, as I am desperate to understand a bit about immune responses and how they work. So onto my question: In my search for natural anti-inflammatory herbs I found Elderberry as potentially being one. Unfortunately, digging in deeper I came across what _may_ be contradictory…

Greetings all! I have a question related to a long-standing problem. I was told by a doctor that one can have a chronic infection (his words were: some old virus that never went away), even though repeated and frequent bloodwork shows: low CRP (>1), low ESR, perfectly normal WBCs and normal general IgG, IgA, IgM. I do not agree with this; I know that infections can evade the immune system, but how is it possible that a chronic symptomatic infection would not be at least causing some inflammation? If an infection is causing a patients symptoms, then surely the infection is doing 'work' somewhere? The only immunological finding is very high leukocyte count in the urine a…