| 00:00 | These two next two things, crayons thyroids. OK? They are not |
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| 00:09 | letters, viruses. OK? They're , they're not considered viruses by the |
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| 00:14 | definition, right? So don't even them the virus. OK. So |
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| 00:20 | prion and a vid uh are both units. OK? One is a |
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| 00:30 | , one is an RN A molecule that's the extent of the structure. |
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| 00:34 | it. There's not nothing else with except that that OK. And so |
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| 00:40 | are prions and so uh your familiarity probably mad cow disease. You may |
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| 00:46 | heard of that. Um I think was first discovered in sheep, I |
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| 00:51 | scrapy is the sheep. Uh version this um Kuru uh is uh I |
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| 00:59 | the practice of cannibalism, OK? uh brains infected with this. |
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| 01:06 | that's what Kuru is still happens, guess in parts of the earth. |
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| 01:11 | But uh the quartz felt Jacob is the they call the human form the |
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| 01:15 | . OK. So um how would human get infected with this? |
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| 01:21 | eating um uh food prepared from an animal? OK. Meat, I |
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| 01:28 | meat from an infected animal. Um uh you know, the, your |
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| 01:34 | of getting this, you're probably chances getting hit by lightning are probably better |
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| 01:39 | get, catching a prion disease. , it's, it's not that |
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| 01:43 | certainly in this part of the Ok. But what's unusual about |
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| 01:47 | of course, is that it's a that's infectious, which is, |
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| 01:51 | really unheard of. And so, , the, uh, and to |
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| 01:57 | knowledge, um, this is the prion type of disease I'm aware |
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| 02:03 | Uh but in any case, what is is you have a normal form |
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| 02:10 | this protein, right? So what is, is basically a protein that |
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| 02:14 | misshapen misfolded. And then this that's what causes the disease. These |
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| 02:19 | accumulate over time. Ok? It's very slow progressing disease, ok? |
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| 02:26 | And uh I mean, there is cure for it. But again, |
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| 02:30 | chances there, there's some evidence that a genetic component to it. Um |
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| 02:35 | um it causes neurological impairment, it neurons in your brain. Um But |
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| 02:45 | the protein itself, you have a form of the protein in your brain |
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| 02:49 | , ok? In fact, in a lot of your cells, |
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| 02:51 | predominantly in your brain cells. And what's called a glycoprotein. OK? |
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| 02:56 | it sits in the membrane of the . OK? The function of it |
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| 03:00 | really still not known, right? some evidence that it has something to |
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| 03:04 | with copper metabolism of all things kind weird. Uh But um, but |
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| 03:09 | hasn't really still been pinpointed what the function is, but if it |
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| 03:15 | um, changed and mutated, then is a definite consequence to that. |
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| 03:21 | . And so, uh, and what all you're seeing here in terms |
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| 03:24 | the normal and abnormal forms is a of the protein? Ok. And |
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| 03:31 | it causes the misfolding. Well, when you have a, what's called |
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| 03:36 | prion protein. So that's a misshapen . OK? It binds to a |
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| 03:40 | form of protein. Ok. how would you get the misshapen form |
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| 03:45 | eating contaminated tainted meat from an animal has this? Ok. There's some |
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| 03:51 | that there's a genetic component to it well. So that could be a |
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| 03:54 | . But regardless the binding of the to the normal protein is what induces |
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| 04:00 | misshape to occur. OK. And this continues to happen and eventually you |
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| 04:07 | more and more good prions into bad if you will. OK. And |
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| 04:12 | these begin to accumulate again. Still doesn't happen overnight. It happens over |
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| 04:16 | years, but you begin to accumulate , a neuron, for example, |
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| 04:21 | accumulate these misshapen proteins and then begin affect its function. OK. And |
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| 04:28 | what happens is the holes you so here's the brain tissue. So |
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| 04:32 | holes you see our neurons once used reside, neuron has basically just |
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| 04:39 | gone away and was left behind is space. OK? So you don't |
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| 04:44 | brain tissue to have, look like cheats. That's not gonna be |
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| 04:49 | a well functioning individual. Ok. , um and that's what they call |
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| 04:55 | plaques sometimes. So uh any case spongy form, so lots of holes |
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| 04:59 | the tissue creates kind of a sponginess . That's why they call it |
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| 05:03 | Ok. So, um it is resistant to various chemical agents and temperature |
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| 05:11 | things like that. So if you to have meat that's tainted with |
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| 05:16 | a, you probably wouldn't know But, you know, you, |
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| 05:18 | really have to heat it very But um, but anyway, so |
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| 05:22 | , it's a, you know, it's just an infectious protein and this |
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| 05:26 | how it multiplies basically by binding a protein and that changes the shape of |
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| 05:30 | . That's kind of quote, the replication occurs this way. |
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| 05:35 | But again, it's just a OK. Um Any questions about |
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| 05:42 | Ok. So, and here's a you a little cartoon of the green |
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| 05:48 | the normal prime proteins in the OK. And the red ones are |
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| 05:53 | ones that are accumulating the bad OK. And eventually it will take |
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| 05:57 | the cell uh killing it, uh and destroying its functions. And |
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| 06:02 | um uh so the last of these , weird types is this infectious RN |
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| 06:10 | uh vid? Ok. So as as I know, thyroids are only |
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| 06:17 | , a um problem for plants. . Certain plants, there's not to |
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| 06:23 | knowledge, these things have yet to any issues in humans, right? |
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| 06:28 | vids are strictly certain plants. I the the most well studied one is |
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| 06:33 | that infects a potato. OK. so what they are of course is |
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| 06:39 | RN A, OK. And uh DNA RN A is not double |
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| 06:45 | but RN A can fold on So it's just just regular complementary base |
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| 06:51 | where these bindings occur. It can these kind of structures. OK. |
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| 06:56 | you see here, um and so structure itself tends to be important for |
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| 07:01 | function. The other thing about RN is it's is that some RNAs can |
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| 07:06 | , you can have enzyme activity, activity. OK. And so uh |
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| 07:13 | example, that's the Rizo Rs puts the amino AIS to make a protein |
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| 07:18 | it's an RN A in the Vibra that actually does that. OK. |
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| 07:21 | some RNAs can have an enzyme activity this does OK. Uh It's very |
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| 07:27 | , 304 nucleotide is pretty small. And so we use the host RN |
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| 07:32 | pli to make more copies of OK. So what what they think |
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| 07:37 | things do is disrupt o question this the normal expression of genes in the |
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| 07:46 | . OK. So it will, things can combined to a transcript. |
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| 07:52 | we have am RN A in a . OK. So then one of |
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| 07:59 | thyroids may kind of bind. Let's call that the thyroid Viro RN |
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| 08:07 | combined on one of these parts of MRN A. Now, the ribosome |
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| 08:12 | here. OK? And because we this big varroid bound to the |
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| 08:22 | it cannot um translate, you can't around it. So it kind of |
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| 08:27 | translation. That's one of the effects has. And so by doing |
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| 08:31 | it, it disrupts expression of certain these plant genes. So that's how |
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| 08:36 | causes disease. Um how these things transmitted from plant to plant. I |
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| 08:42 | know that that's known. OK. But regardless it's, it's, you |
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| 08:47 | , just it's all it is is A, that's it. Nothing else |
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| 08:50 | it. Uh replicates using host, plume and uh that's pretty much |
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| 08:56 | OK. Disrupting gene expression. So you have an infectious protein and |
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| 08:59 | infectious RN A uh vid. So let's um look at all rights |
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| 09:10 | soprano. So which statement? Part of it may be true, |
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| 09:14 | the whole thing has to be The whole thing has to be true |
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| 09:18 | you're gonna pick it. OK. we have a um viro prions like |
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| 09:26 | capsule thyroids. Lactic acid B, contain DNA and RN A Ryan is |
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| 09:36 | on it. Prime particles can increase numbers. So aids cannot I require |
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| 09:43 | plym race cry on do not. crayons can recombine with hosts. Can |
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| 09:53 | recombine with host? OK. That's bad. English can recombine with the |
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| 09:57 | of the genome with host genome with host genome. That's what it's supposed |
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| 10:02 | say. Ah, ok. With host genome? That's better. |
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| 10:12 | Uh vids cannot, or none of above are completely true. Ok. |
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| 11:04 | . Let's count down from 10. . Yes. If you answer d |
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| 11:22 | are correct. OK. So that's , any questions? That's how we're |
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| 11:29 | do today, folks. We'll wrap up on Thursday and then start chapter |
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| 11:35 | . Ok. Thanks |
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