| General > General Technical Chat |
| Covid 19 virus |
| << < (76/381) > >> |
| iMo:
--- Quote from: Cerebus on March 16, 2020, 05:27:08 pm ---..The SARS-Covid-2 virus has a genome with about 30,000 base pairs, that means (crudely) it can only code 10,000 amino acid sequences, quite a few of which are overhead. Compare that to a computer virus with 30,000 bytes assembler instructions and 10,000 actual instructions. That little genetic material has to code for the structure of the virus, how it gets into a host cell, how it gets that host cell to manufacture more virions and so on. .. --- End quote --- The virus is a chunk of RNA encapsulated into "the debris" of the cell's outer membrane (the cell which burst because of the mass-produced RNA). Thus the "how to get into the cell" is not coded in the RNA itself, but specified rather by its encapsulation - and while it is made of the cell's outer membrane the barrier to enter into an another identical or "similar" cell is almost nil, imho. |
| vad:
--- Quote from: not1xor1 on March 16, 2020, 09:18:54 am --- --- Quote from: vad on March 15, 2020, 09:39:32 pm --- --- Quote from: not1xor1 on March 15, 2020, 05:16:49 pm ---just see this: --- Quote ---...We hypothesize that SARS-CoV-2 does as well. --- End quote --- --- End quote --- Nice hypothesis. Let me know when you’ll find a peer-reviewed article that starts its conclusion with the phrase “we established” instead of “we hypothesize”. --- End quote --- well if you do not like how science works you can always try cow urine ;D --- End quote --- It seems you have a lot of aspiration for science. Keep on trying, don’t give up, and take my advice. Today I am giving it away for free. When googling for something that can prove your theory, don’t search for words like “urine”. Try something different. ”Chi-squared test”, for example. |
| Cerebus:
--- Quote from: imo on March 16, 2020, 07:05:57 pm --- --- Quote from: Cerebus on March 16, 2020, 05:27:08 pm ---..The SARS-Covid-2 virus has a genome with about 30,000 base pairs, that means (crudely) it can only code 10,000 amino acid sequences, quite a few of which are overhead. Compare that to a computer virus with 30,000 bytes assembler instructions and 10,000 actual instructions. That little genetic material has to code for the structure of the virus, how it gets into a host cell, how it gets that host cell to manufacture more virions and so on. .. --- End quote --- The virus is a chunk of RNA encapsulated into "the debris" of the cell's outer membrane (the cell which burst because of the mass-produced RNA). Thus the "how to get into the cell" is not coded in the RNA itself, but specified rather by its encapsulation - and while it is made of the cell's outer membrane the barrier to enter into an another identical or "similar" cell is almost nil, imho. --- End quote --- I don't mean to be harsh but 'IMHO' is not a substitute for actually having studied this. A virus' protein coat is encoded in its genome, it doesn't just grab scraps of a cell's (phospholipid) membrane on the way out, it gets its host cell's ribosomes to manufacture its coat proteins. Take a look at a T4 bacteriophage and tell me how it constructs the complex protein coat (including a 'hypodermic') from a bacteria's shattered cellulose/phospholipid membrane. Getting into or out of a cell past the membranes is not a trivial task biochemically speaking, that's why cells have whole systems of proteins dedicated to active transport, ion channels in cell membranes and so on, and active mechanisms to resist 'foreign' biochemicals simply wandering into the cell. Case in point, our friend SARS-covid-2: --- Quote from: https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2#Structural_biology ---Structural biology Each SARS-CoV-2 virion is approximately 50–200 nanometres in diameter.[50] Like other coronaviruses, SARS-CoV-2 has four structural proteins, known as the S (spike), E (envelope), M (membrane), and N (nucleocapsid) proteins; the N protein holds the RNA genome, and the S, E, and M proteins together create the viral envelope.[51] The spike protein is responsible for allowing the virus to attach to the membrane of a host cell.[51] --- End quote --- Note in particular that very last bit about the virus' spike proteins. The structural similarity of the spike protein to antibodies is no accident, it performs a similar task to 'recognise' and attach to surface expressed proteins on a target cell. Why would it code for a membrane protein if it was just going to snatch a cell's phospholipid membrane to do the job? |
| nctnico:
--- Quote from: Kjelt on March 16, 2020, 06:49:48 pm ---For the first time since 1973 our PM addressed the country. The strategy is to isolate as much as possible the elderlyand vulnerable till its over. The rest of the population should over time get the virus in a natural way, so they get immune after they recovered so they don't pose a thread anymore after a certain period of time. --- End quote --- Just for clarity: it wasn't the same PM as in 1973. Still it is impressive. Never thought I'd see the day but yet here it is. His main message was that most people will get infected at some point (which is what Merkel; the PM of Germany also stated a couple of weeks ago). The efforts are aimed to control the outbreak so health care can keep up. Makes sense to me because that seems the only way to me to keep both the economy going and reduce loss of life. |
| edavid:
--- Quote from: rgarito on March 16, 2020, 05:47:34 pm --- --- Quote from: edavid on March 16, 2020, 04:04:52 pm ---Does anyone know if the PCR tests being commonly done by public health services are quantitative? How about the antibody tests? I've read articles that mentioned both viral load and detected/not detected results. --- End quote --- At least in the USA, the PCR tests are pass/fail tests. The test basically slices and dices the sample RNA, making copies each time, matching on 3 different sample patterns found in the virus. Each one is tagged with a dye which is then measured (after each copy iteration). This will generate a curve of the fluorescence at a specific wavelength. They plot this on a graph and if all 3 different dye tags cross a specific threshold within a specific # of replications, its a positive test. --- End quote --- So how do they do an "N-gene-specific quantitative RT-PCR assay", as described in this article: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30113-4/fulltext Is it a lot more difficult than the pass/fail test you describe? |
| Navigation |
| Message Index |
| Next page |
| Previous page |