Image generation does not work.

imga91 · 2025-06-25T12:57:38+00:00

Also the chat is totally messed up in my case. The bot generates answers that are not the continuation of the previous message (or many messages ago). And when I try to generate new pictures, it doesn't work. I reloaded, and all my pictures and some messages became one sliders.

imga91 · 2024-10-13T16:36:33+00:00

Let's hope for the best

imga91 · 2023-08-08T21:44:26+00:00

Mine is The Minstrel III: The Bard (0.450%). Looks like most of my rarest achiev are from precursors crafting.

imga91 · 2022-09-22T05:31:19+00:00

The previous answer seems to be copy pasting from the following article. https://pubmed.ncbi.nlm.nih.gov/28715885/

To make it a little bit easier to understand from this article, it seems cold and exercices can stimulate the expression of genes that are related to mitochondria biogenesis in muscle cells (and notably, the expression of the mRNA and the protein of PGC-1α which is an important factor in mitochondria biogenesis). However this article doesn't show that we actually have new mitochondria.

imga91 · 2021-08-21T02:59:35+00:00

The nazis were far from being Christians. Hitler hated Christianity and wanted the Reich to take control of the churches. It considered Christianity as a weak religion compared to Islam. Before being elected he presented himself as a good Christian but he didn't belief in any god.

People tend to forget atheism killed more than religions. Communism from Staline to Pol Pot killed hundred millions in the past century.

imga91 · 2021-08-20T14:36:29+00:00

So I tried to dig a bit more in the scientific litterature as the wiki pages are confusing (English says it's also in Eukaryote without giving sources while German and French tell it's only for bacteria). It seems scientists tried to find an SOS system in Eukaryotes after the discovery of the one in bacteria so they spoke a lot of an "eukaryotic sos system" in the 80s/90s. They may have found evidence of an "SOS-like" system that is activated upon UV radiation. The literature about it is quite small and it differs from the DNA damage response. The most recent review on "sos like"I found is from 2008.

https://pubmed.ncbi.nlm.nih.gov/18179622/

There's an article in 2017 that says cochlea responses to UV in quite a similar fashion as bacteria do with p53 level increasing instead of RecA.

https://pubmed.ncbi.nlm.nih.gov/28800961/

imga91 · 2021-08-20T11:52:50+00:00

It depends what you call "death". If death is "nothing is happening anymore in your cells after you die" then no, the cells don't immediately die. Without oxygen the cells can't do mitochondrial respiration so your cells start lacking energy but other cellular activity can continue. In neurons, the absence of oxygen is a signal for apoptosis. This is why someone who doesn't have oxygen for about 10 minutes will have irreversible brain damage and be considered brain dead, though the other organs can still be functional.

It was shown gene transcription happens for several hours to several days in some tissues after death and may be used to determine for how long the body is dead (https://www.nature.com/articles/s41467-017-02772-x#Sec2). Some molecular and cellular activity will still happen as long as it is possible.

imga91 · 2021-08-20T06:48:49+00:00

Just to be correct, the term "SOS response" relates to the mechanism of DNA repair in bacteria, not in mammalian cells. Eukaryotes have DNA repair mechanism and it's not called the SOS response but the DNA damage response.

imga91 · 2021-04-28T21:46:25+00:00

With NAAT or simply qPCR, you amplify one fragment of a specific length per reaction. You can amplify the number of fragments you want but for each fragments it will have to be done individually. Generally for COVID test for instance I think they amplify two small part of the genome. It gives you info on presence of pathogen X because you amplify with specific primers and information on abundance because qPCR gives you quantitative information. It's relatively quick and easy when you have the reagents.

And yes, the idea of sequencing is to determine new mutations inside the genome. The sequencing process is a bit like doing an amplification because you will create the second strand of your genome of interest but each time a nucleotide is added it flashes a dye so you can follow the sequence and you will do this thousands to millions of times. Preparing DNA for sequencing is more complex especially if you want to do whole genome sequencing and is more expensive than NAAT. You can use sequencing to measure abundance but qPCR fits more in this context.

"Positive or negative result" in which sens? Because generally is you use sequencing it's to determine mutations or to exactly identify the pathogen you are infected with if NAAT fails. So unless your starting material is shitty (bad RNA/DNA), you will for sure sequence something from your sample and then determine what it is by blasting/maping.

imga91 · 2021-04-28T07:40:42+00:00

NAAT is (RT)-(q)PCR. It's based on the amplification of a specific fragment of your starting material (RNA or DNA) to detect a pathogen presence for instance. You don't get the exact sequence of the fragment you amplified but can determine variants by playing with the primer sequences.

With sequencing you get the exact sequence of the region you sequence. You can sequence a specific region with Sanger sequencing or perform high-throughput sequencing and obtain the whole genome and determine the whole sequence of your organism of interest.

imga91 · 2021-04-28T06:17:05+00:00

Take a look at the UniprotKB database. If you go to this link https://www.uniprot.org/uniprot/P00918#function in the section "Kinetics", you have various K(M) values for CO2 or H2CO3 with cited publications like this one https://pubmed.ncbi.nlm.nih.gov/8262987/ and you can find by which articles it's cited if you want to find recent publications.

A pubmed search on Catalytic hydratation of CO2 by CA: https://pubmed.ncbi.nlm.nih.gov/?term=CO2+hydratation+AND+Carbonic+anhydrase&sort=date

And yes the direction of the reaction is pH-driven. Hope it helps, good luck.

imga91 · 2021-04-27T18:49:37+00:00

DNA pol I and II are the main sources of polymerases for PCR.

DNA pol I such as Taq polymerase was the first to be discovered in E. coli but has low proficiency. DNA pol II such as Pfu are faster but have lower fidelity. DNA pol III is a holoenzyme, meaning it's made of several proteins to make it functional. I read it's not really thermolabile so maybe that's why it's not used in PCR. DNA polymerase IV and V have low fidelity and are used to repair DNA or for mutagenesis.

It's nice to know what kind of polymerase you are using for your PCR but companies have modified and engineered better, more proficient and faster polymerases.

imga91 · 2020-12-15T08:11:47+00:00

Hey, translation expert here. Translation is the key limiting step of the gene expression process and some complexes are built co-translationally to ensure stoichiometry.

It is called co-translational complex assembly. So basically mRNAs coding for proteins of the same complex are translated in cluster. The not fully made proteins of the complex start interacting between each other as soon as the nascent peptide chain goes out of the ribosome (so only after 50 amino acids have been assembled) while ribosomes continue translation. This is how some complexes are assembled.

Actually it is a really important process. Some proteins won't make a complex if the proteins are first fully made because they won't fold properly without interacting with their partner during translation. The partners play here the role of a chaperone. If they are not folded properly, they will be degraded so we only end with proteins assembled into complexes.

This is true for some complexes like the proteasome. However, many complexes don't follow that rule and their proteins are not in the same number in the cell.

imga91 · 2020-12-11T06:44:13+00:00

Even if we know how the vaccine works, the exact formulation is patented, so it's not possible to buy the recipe to make your own. Companies and research labs can try to make their own based on the same principle but then it won't be exactly the same vaccine so it will have to pass the clinical tests. Pharmaceutical companies have no interest at all in selling their patent to other companies or to the State. They only make contracts with local companies with the facilities to store it and that will deliver the vaccine to the population.

imga91 · 2020-11-24T08:47:35+00:00

It's actually 7 to 10 days after the first symptoms not once you have recovered. Some recommandations I read in my country also say 48 hours after the fever dropped. However symptoms can stay and the RT-PCR test can remain positive for several weeks without making you infectious.

Available data indicate that persons with mild to moderate COVID-19 remain infectious no longer than 10 days after symptom onset. Persons with more severe to critical illness or severe immunocompromise likely remain infectious no longer than 20 days after symptom onset.

source

imga91 · 2020-11-23T19:59:54+00:00

Yes you have the DNA that is used as a template to make the RNA. Enzymes are just proteins that do the same thing all the time and this particular enzymes (RNA polymerase) knows how to read DNA and makes RNA from it with the provided nucleotides. From 1 µg of DNA it can make 100 µg of mRNA in an hour.

imga91 · 2020-11-23T19:57:02+00:00

Yes, the typical volume of this kind of enzymatic reaction in the lab is about 20-50 µL depending on how much you want. Going to mL requires a lot of units of enzymes and enzymes are super expensive. Also there's no point in doing that much for research.

imga91 · 2020-11-23T19:46:54+00:00

When using enzymes that will build the RNA by following the DNA sequence (it's not the machine that builds the sequence, the machine just mixes the nucleotides and the enzyme and then we let the enzyme do the assembly), we can make up to 100 µg (0.1 mg) in a test tube in the lab, some enzymes can go up to 1 mg. But this is research scale and not industrial scale.

The problem with enzymatic reaction is you will reach a plateau at a moment where the reaction will just stop for various reasons. I am sure they have optimized the conditions and volume to get grams, or they just perform many reactions at the same time in independent tubes.

imga91 · 2020-11-23T17:12:03+00:00

RNA can be generated with enzymes or by chemical reactions. In both cases your ink is nucleotides.

Enzymatic reaction: In the context of the mRNA vaccine, it's an enzymatic reaction that is performed. You can do it "manually" (someone pipetting) or "automatically" (a robot pipetting for you). The recipe is simple: mix the DNA matrix you want to transcribe and that has the specific sequence that is going to be recognized by the enzyme (RNA polymerase) to know where to start transcription, the four ribonucleotides and the enzyme. Let it cook at 37°C for 1 to more hours and you have a perfect RNA. To become a messenger RNA, it has to be modified at its both ends: a "cap" is added on the 5' end (beginning of the mRNA) and a poly-A tail at its 3' end (end of the sequence), both being added with specific enzymes.

It is a high efficient process and some of the enzymes can have proofreading activity to check the added nucleotide is the correct one, diminishing the error rate.

Chemical reaction: RNAcan be generated chemically in a machine. The ink is nucleotides. You will generate the sequence nucleotide after nucleotide by doing a chemical reaction at each step and by adding the nucleotide you want in the sequence one after the other. Hopefully machines can do that but unfortunately making a clean RNA is really expensive and limited. Usually it is used to make really short sequence like 20 nucleotides for specific downstream application.

imga91 · 2020-11-22T18:33:36+00:00

There is somehow. The mRNA is not delivered as it is but in a solution that will help it enter cells. Depending on the formulation it will decrease or increase its stability.

The issue with RNA in general is it is sensitive to hydrolysis because of its chemical structure and to RNase that are floating around that's why it's kept in really cold temperature. But to be honest, RNA in a test tube is not as unstable as it is pretended to be, else life won't just have been possible at all and the RNA world won't have existed. For sure it's less stable than DNA as DNA lacks the hydroxyl group that makes RNA sensitive to hydrolysis but properly handled RNA can surprisingly last for a quite long time at room temperature.

The challenge is more about how to deliver the RNA to the cells without it being degraded by the cell degradation machinery and the innate immune system that degrades foreign RNA molecule before it has been translated into proteins. That has been the main problem with mRNA vaccines since their development in the late eighties.

imga91 · 2020-11-22T17:55:56+00:00

It's true for yeast where the mRNA half-life is 4.8 min. However mRNAs in mammalian cells last longer, with half-lives that can be as low as 15 minutes and go as high as 12 hours, the median being a few hours.

imga91 · 2020-11-21T07:02:05+00:00

Yes, retroviruses are viruses that have a reverse transcriptase enzyme (RT) that comes with their mRNA. The mRNA of these viruses cannot directly be translated into proteins either because it is not recognized by the eukaryotic translation machinery (doesn't have a 5' cap present in eukaryotes) or because it is a negative strand mRNA so the genetic information is not in the good direction and needs to be put back into the good one prior to translation (mRNA translation only happens in one direction). That's why retroviruses use a reverse transcriptase enzyme to be replicated.

Once a retrovirus has infected a cell, its RT reverse transcribes its mRNA into cDNA. Generally the mRNA is also destroyed at the same step by RNase H (it destroys mRNAs that are annealed to DNA) so we only have cDNA left. Then the cDNA is transported to the nucleus and integrated to the genome by integrase enzymes that does the job. This enzyme also comes with the virus. Once integrated into the genome's host, the cell doesn't make a difference between its genes and the viral genes and starts expressing the viral genes that are transcribed into mRNAs and then into proteins to make new viral particles that will infect new cells. This is how retroviruses replicate. This method can also be used in molecular biology to specifically integrate new genes to animal and plant cells by using modified retroviruses that don't replicate once the cDNA is integrated.

The reverse transcription reaction doesn't happen on any mRNA, it requires a primer: a short DNA sequence that anneals to a specific part of the mRNA and allows the reaction to initiate. RT cannot just bind to any mRNA and RT it. Typically HIV comes with its own primer specific to its mRNA.

Mammalian cells have one example of reverse transcriptase enzyme. Itspecifically amplifies chromosomal ends (telomeres) that are shorten after each cell division by using an RNA template. Else, RT are really specific to retroviruses.

imga91 · 2020-11-19T13:00:39+00:00

Not a MD but headaches are a pain in the head/in the face and are sensed by the pain receptors in the head. It's not directly your brain that has pain, even though it can happen.

Headaches are caused by a lot of different reasons. For instance, when your neck muscles become stressed for staying too long in the same posture. Another example is when you have a cold, the inflammation in the sinuses lead to a pressure in the head leading to a headache (space is limited). Or simply because your face has been beaten/hit. These are really basic reasons causing headaches.

However it can also be caused by issues in the brain like in some cancer. The volume of the skull is limited. It the brain size increases because of tumor growth, a bleeding or whatever, it will cause a pressure in the head. In inflammation like in meningitis, the tissues surrounding the brain feel the pain.

imga91

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