Hi all, I am trying to stain perineuronal nets and I am using a biotin primary (Sigma WFA 1:400) and a Streptavidin secondary conjugated to Alexa 488 (thermofisher 1:2000). I am using abcam's biotin/avidin blocking kit (15 mins in one block, rinse twice, 15 mins in next block, rinse twice then primary). I feel like my images have high background and I would like to reduce it further. Any suggestions? I wasn't sure if maybe I could somehow block better? Or should I just try different dilutions? Is it just normal to have high background with this stain?
Avidin in uncooked egg whites can lead to a biotin deficiency. Same thing applies to egg white powder unless it's pasteurized at 85 degrees which deactivates the avidin.
Looks like companies don't disclose the temperature pasteurized at for some reason, so with taking egg white protein powder better to assume Biotin needs to be taken alongside it.
But i'm wondering how much Biotin would offset the avidin impact? does it just apply to biotin absorption ingested around the same time or would it impact biotin taken earlier / later too when the avidin is ingested on a daily basis?
edit: seems avidin has anti-nutrient effect on biotin in the digestive tract so would impact biotin taken which isn't aborbed yet. not sure how long it takes intestine to absorb biotin. i guess if you take a lot half a day apart it should still have a countering effect?
Raw egg whites contain anti-nutrients such as Trypsin and Avidin which bind tightly to biotin.
In laboratory conditions, biotin deficiency can be induced by feeding raw egg white diet to animals.
Heat is known to denature these anti-nutrients.
However I have seen mentions that the mechanical action of whisking also denatures these anti-nutrients, but I don't seem to find the actual studies on it. Does anyone have any links to point me in the right direction ?
Any other labs using ABC Peroxidase always run out of Solution B first? Whyyyyy
This is our experience with both Thermo Scientific and Vectastain
Has anyone ever heard of such a thing? I'm working with cell-penetrating peptides and I'm trying to figure out the extent to which which they're escaping endosomes (or if they're escaping at all). Simply tripsinizing heavily, cracking the cells, and seeing if I get counts with 35S-met would tell me if the CPP is internalizing, but not if they're getting out of endosomes.
It occurred to me that if I had a cell line that expresses avidin or streptavidin, I could biotinylate my CPP and use that to figure out if the CPP is internalizing + escaping endosomes + available for binding all at once. Does anyone have an idea if this is possible or just a crazy thought? I've been doing a lit search but I haven't turned up any examples of people trying to do something similar.
Original citation: Lesch, H. P., M. U. Kaikkonen, et al. (2010). "Avidin-biotin technology in targeted therapy." Expert Opinion on Drug Delivery 7(5): 551-564.
Link to paper: http://informahealthcare.com/doi/abs/10.1517/17425241003677749
I've run into enough paywalls today. If any of you have access, please, send me this paper.
I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.
Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.
Do your worst!
Hi,
I'm a chemist working on a new theoretical method to analyze interactions between molecules. We want to expand it into the bio space. The problem with our method is that it's very computationally expensive, so we are limited regarding the size of systems we can handle. The project is more a proof of principle, so this isn't a big problem and computational power is growing fast so not too concerned about this limitation right now.
However, I'm looking for a small protein that has some known inhibitor or really any kind of drug interacting with it. Ideally there's a crystal structure with the drug or at least known what the active site is.
Would really appreciate ideas, since I have no idea how to look for something like this.
Thanks a lot.
They were cooked in Greece.
I'm surprised it hasn't decade.
For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.
I said "hey look, an escaPEA"
No one near me but it didn't half make me laugh for a good hour or so!
Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂
It really does, I swear!
Because she wanted to see the task manager.
Heard they've been doing some shady business.
We've extracted lysozyme and avidine from the eggwhite of a chicken egg and tried to isolate them via ion exchange- and affinity chromatography. For the affinity chromatography we've used iminobiotine-sepharose which biotine binds to. We did that in order to separate lysozym from avidine by letting avidine bind to the biotine-analogue while elute the lysozym.
Right now I'm trying to figure out the mechanism how biotin binds to avidine. Unfortunately I can't really find any arcticle or paper explaining it. For the protocol I have to discuss the reason why iminobiotine is used in the gelmatrix instead of regular biotine.
I know that it's because of the different KDs. biotine-avidine-complexes are one of the strongest non-covalent interactions between protein and ligand while iminobiotine-avidine-complexes are weaker. But how does the ketone in biotine cause a higher KD than the imino-group in the analogue? Is it due to the higher electronegativity of the oxygen? Which parts of the compounds are interacting with each other in general? Am I right to say that the ketone/imino group binds to the avidine?
but then I remembered it was ground this morning.
Edit: Thank you guys for the awards, they're much nicer than the cardboard sleeve I've been using and reassures me that my jokes aren't stale
Edit 2: I have already been made aware that Men In Black 3 has told a version of this joke before. If the joke is not new to you, please enjoy any of the single origin puns in the comments
Don't you know a good pun is its own reword?
They’re on standbi
A play on words.
My daughter, Chewbecca, not so much.
Pilot on me!!
Nothing, he was gladiator.
Or would that be too forward thinking?
Dad jokes are supposed to be jokes you can tell a kid and they will understand it and find it funny.
This sub is mostly just NSFW puns now.
If it needs a NSFW tag it's not a dad joke. There should just be a NSFW puns subreddit for that.
Edit* I'm not replying any longer and turning off notifications but to all those that say "no one cares", there sure are a lot of you arguing about it. Maybe I'm wrong but you people don't need to be rude about it. If you really don't care, don't comment.
Disclosure: I bought 150 shares of $SRNE at an average of about $5.65CAD. I’m not a medical or financial professional, and this information is provided as-is. Most information from this post is from https://sorrentotherapeutics.com and from clinical trial profiles from clinicaltrials.gov.
Sorrento Therapeutics has a suite of products on the horizon to detect COVID-19, treat COVID-19, and rescue patients with severe cases of COVID-19.
Detect
First, there is COVISTIX. COVISTIX is an antigen test to detect the SARS-CoV-2 Virus. Here is an excerpt from their website:
“The test uses a proprietary platinum nano-catalyst core (PtNC) which yields up to 100-fold increases in sensitivity over conventional lateral flow colloidal gold assays. As viral antigen passes over the labeled antibody, the sample encounters the PtNC particles targeted specifically to the virus nucleocapsid(N) or matrix (M) antigens. The antigen is then captured in a strong biotin-avidin complex, producing a conspicuous black line on the membrane stick, indicating a positive result.
Initial validation of COVISTIX has demonstrated a sensitivity of 98%, a specificity of 100%, and an LOD of 6.25 TCID50/swab (exact values to be confirmed by the FDA). COVISTIX has been tested for cross-reactivity and is specific for detection of SARS-CoV-2 and viruses in the same family. As a platform technology, the PtNC lateral flow also has the potential to be developed as a multiplex system to detect other respiratory pathogens leveraging the same assay, processes, and training. A request for EUA of this technology has been submitted in December of 2020. We are also evaluating the potential for COVISTIX using a saliva sample as well. Development plans include multiplexing this platform to enable a patient to tell if they have COVID-19 or Flu A/Flu B.”
This antigen test appears to superior to conventional antigen tests. In a comparative study with all available EUA-approved COVID-19 virus rapid antigen detection tests, COVISTIX demonstrated its superiority in some areas. COVISTIX is currently approved and marketed in Mexico, Brazil and is CE marked in Europe. [[https://www.globenewswire.com/news-release/2021/12/27/2358093/0/en/Sorrento-Announces-COVISTIX-COVID-19-Virus-Rapid-Antigen-Detection-Test-Detects-the-Omicron-Variant.html](https://www.globenewswire.com/news-release/2021/12/27/2358093/0/en/Sorrento-Announces-COVISTIX-COVID-19-Virus-Rapid-Antigen-Detection-Test-De
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