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BIOL 2321_Microbiology for Science Majors - 2321_10_10_23_CH06
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00:00 Yeah. 10. Oh yeah Oh, what you want?
00:47 Testing, right? Evo, there go. It's good, good alarm
01:02 . Ok. Um, all Uh, let's see. So,
01:08 , today we're gonna continue on, , with viruses. Uh, I
01:14 into a little bit of life cycles this kind of the part two
01:17 Um, uh, so Thursday, , if you haven't gotten the
01:23 um, class is for you is but optional for me but for
01:29 Ok, so I'm gonna, our class obviously are recorded. So,
01:34 , we'll do clickers because we need have something else to do besides just
01:39 talking. So, uh, but clicker points just, just for
01:43 All right. So if you're not to make it, don't, don't
01:47 . Ok, you're not gonna be . There's still people that think I'm
01:50 to get them. All right. got an email saying, ok,
01:54 said off so fast but we're not count for Clippers. Of course
01:57 Why would I do that? we're not gonna do that.
02:02 Um, what else? So, know, I don't know how bad
02:07 gonna be on Thursday but I, , because I get emails you don't
02:12 , so I get emails, from the provo saying that said at
02:15 beginning of the semester as you make syllabus account for this day.
02:19 it's like, I guess I didn't it seriously enough because I didn't.
02:23 , uh, but II, I that parking garages are gonna be closed
02:26 you're like a f zone parker like , you're really restricted. And
02:33 um, uh, so anyway, like the east garage is open and
02:38 , I don't know, it's, a lot of, it's gonna be
02:39 cluster, you know what, on ? Probably. So, um,
02:44 , so I just said, I'll, I'm here early anyway.
02:47 I'll have a class and you're, here show up if you don't want
02:50 hassle. Fine. Ok. Uh regardless the, the video lecture we
02:55 after class on Thursday. So, um, we should uh finish up
03:02 of six. We probably have some into, into next Tuesday, which
03:08 a day to catch up on stuff . So, um, and
03:13 you know, you can always go some of the stuff on review,
03:16 of the stuff on part two uh and whatever, whatever you wanna
03:21 . So, um, we can decide that on Tuesday. But
03:26 um, all right, so we a unit quiz. So remember those
03:30 longer, more comprehensive, right? , um, it will cover stuff
03:35 six. So do look at that lecture, they'll be posted Thursday if
03:40 don't make it to class because it cover Thursday stuff on there.
03:44 Um, smart work that's due next . Ok. So, um,
03:52 think that's everything. Ok. Any about anything? Ok. So,
04:01 , let's do a little bit of rehash and I actually, uh,
04:05 thought of this about 15 minutes maybe about 30 minutes ago. And
04:11 is uh in doing this recap Um Well, I'll tell you in
04:18 second. So let's just kind of through this first. So, um
04:21 right. So we talked about this time we introduced, introduced viruses,
04:25 ? So viruses are that uh we about this back on day, one
04:30 back when viruses have on that like, are they living, are
04:34 not living? Um they're only really , I guess if they're inside of
04:40 host cell kind of replicating outside the . Hm, maybe, maybe
04:46 So, um so, um so we looked at viruses, we looked
04:55 , OK, here's, here's we know they're super tiny, right?
05:00 nanometer scale size. OK. Uh they do span a range of sizes
05:06 that range. Um The term obligate intercellular parasites, right? They have
05:13 have a host, they're obligated you gotta have a host.
05:16 And that host uh to varying degrees on the virus um provides the
05:24 the things it needs to replicate. again, you know, there are
05:29 obviously the virus can do uh bring it, OK, to enable its
05:34 , right? That's why I've asterisked things. So some, some
05:39 some don't have their DNA plumb, sue them, some do, some
05:42 have their RN A plum. So kind of depends on some of
05:44 but certainly for things like ribosomes, , nucleotides, these are things it'll
05:50 from the host. OK? you know, viruses, you can't
05:54 a virus glucose and say carry out respiration, you can't do that.
05:59 . So you don't really have a in that sense. OK. The
06:04 and so as we get into part , beginning end of today, on
06:11 , uh the life cycle itself, lots of variations depending on the viral
06:16 . And um but what they all in common, of course, is
06:21 going back to these terms, we about last time infectivity. That's all
06:27 this, this part happening here, host recognition is that gonna happen or
06:31 all about what are the molecules on , on the periphery of the host
06:35 virus? Very specific, right lock and key if you will.
06:40 . And so if that match that up, then it can enter.
06:43 so there's different ways you can enter high, the whole virus can typically
06:47 in or maybe just the genome comes . So you see variations Uh Of
06:52 , if you're gonna uh you can some type to integrate your genome into
06:57 host. OK? Um If they that, they're gonna have to at
07:01 point uh come back this way to new viral particles. OK. Then
07:06 course means, so you have to in terms of here's what's coming
07:11 right? Here's what's going out. what you gotta do in between,
07:15 you gotta make lots of viral proteins assemble into, into the capsid,
07:20 ? You've got to make copies of , right? Because all these have
07:24 have a copy of the genome in . So that involves a lot of
07:27 . So basically the cells taking over host, it's, it's making it
07:31 a virus factory if you will, it's actively replicated. OK. So
07:38 that's, that's what the intracellular replication is kind of about, that's basically
07:43 the host cell a factory to, make bio particles. OK. And
07:48 then the last thing here is host and tropisms. Remember the difference
07:53 OK. So, uh host range um about the uh how many a
08:02 virus about type, how many hosts infect, right? Rabies virus can
08:08 a possum, a squirrel, a , a bat, right? Wild
08:11 , right? Right. Uh But a single host, a bat,
08:16 say the rabies virus infects uh uh , right? Central nervous system.
08:22 so in terms of tropism, it's that's pretty much it in terms of
08:26 it effects in a single host. . And um uh right. And
08:35 , um uh let's see what I say. So, in terms of
08:40 , then it's within a single how many tissue types can be
08:45 Ok. How many tissue types can affected? So, Ebola can affect
08:49 different types, which is contributes to mortality rate, very high,
08:53 Very deadly. So, um and , you know, recognizing uh it's
08:59 about recognizing molecules, right? The and the and the host uh
09:04 Ok. And so um so that's I kind of wanted to just phrase
09:09 a long time but for a few . Um uh so I, I
09:14 thinking, ok, what is um there right now in the world from
09:21 viral standpoint that's causing issues? And so I looked, oh,
09:28 that I didn't do that. I here. Ok. I said,
09:33 , what's the current outbreaks? And so among others you can see
09:40 here um among the lists here on side, uh I looked at like
09:49 notices affect the international travelers, So Nepa virus in India. So
09:53 the heck is that? I never that one before. Ok. Um
09:58 there look on the other side, like uh small turtles, salmonella
10:04 august 23 ice cream listeria, those often go hand in hand,
10:08 Lister infections and, and ice cream manufacturers um because listeria can grow at
10:16 temperature and, and even at freezing , it can grow slowly but it
10:21 grow um fungal meningitis. Ok. so, you know, these relatively
10:29 . So it's um so looking at virus here. So where does
10:33 where does that take us? let's look at this. All
10:36 Boom. So the outbreak, this of India, ok. Uh called
10:45 and uh so person to person of course, you know, viruses
10:50 spread or any infectious agent, it's to person that, that is the
10:55 problematic. Ok. Um Let's Let's go to what is, what
11:00 the virus? Ok. Let's click that. Ok. Let's go see
11:05 kind of detail we get here. ok. So spread through uh contact
11:12 infected animals. All right. So a zoonotic, they call zoonotic
11:16 Ok. Uh Found that animals can transmissible to humans. Ok. And
11:23 the uh uh and again, it to be uh bats or pigs.
11:28 bat bats, uh and there's a of viruses recently that, that that's
11:32 origin in bats, uh COVID, Ebola, uh SARS virus, there's
11:38 number that bats are kind of the point. Ok. Or the source
11:43 . Um So if you go into little bit more detail here, what
11:47 can we find out? That's what looks like over on the right?
11:51 . So, um and it gives a bit of a description here.
11:55 . Um It is uh the uh , so that's one thing I
12:02 I missed here. That was the one. Um ok, year.
12:14 It was found initially in, in and in the area where they were
12:19 the pigs were bats around. So seems to be what the connection
12:24 Ok. So, um so we on here. Oh, there it
12:29 . Ok. So it was found 1999. So not that not that
12:35 ago. Ok. And uh out pigs. So Malaysia and Singapore seems
12:40 be the source here. OK. so uh and we can look at
12:44 of, we can look at any virus, right? And we can
12:48 a similar type of information. And so um you know, where
12:53 it, where is it found Where if it's an outbreak, what
12:56 the sources? Um how's it So all this kind of information,
13:00 is all from the CDC CDC OK. Uh Center for Disease
13:05 I'm sure you know that um but know, in that initial outbreak,
13:11 cases and 100 deaths. So that's uh something insignificant. OK. And
13:16 to control it, not surprisingly um more than a million pigs,
13:22 To get eradicate. The virus done with like salmonella and, and
13:28 thousands of chickens, you know, they were the source of the
13:32 So, um not uh a common to do in these kind of
13:37 OK. So let's get more details the virus here just because that's what
13:42 talking about mostly is the structure and . So this is again, you
13:47 , we need to write this I'm just, we're gonna talk about
13:50 A viruses but it is um uh to, there we go just to
13:57 you some of the features here. . So a uh a negative strand
14:02 A virus. OK. So, we talked about since anti sense
14:06 that's where this is gonna come in , right? If you remember that
14:10 uh minus RN A viruses have a bit different um life cycle because of
14:15 type of genome, right? um but this grouped in with things
14:21 uh COVID is a minus or a . Um mumps, measles,
14:26 rabies, a number of measles and , a number of common viruses that
14:32 uh humans is in that group. . And um let's see the uh
14:39 at structure. So that's what it like. And so I never heard
14:43 uh virus um characterized as uh Yeah. There it is, it's
14:53 . Um remember that's a non uniform , right? So this virus apparently
14:57 have a uniform shape, obviously. it kind of blobby looking amorphous if
15:02 will. OK. Um They have size range as well among the,
15:09 the types of overlying membrane over lipid , that's the envelope, I'll talk
15:15 that in a second, right? covering the caps, which is the
15:20 protein shell. And so, um , you know different types of information
15:25 the genome. Uh how it is kind of packaged if you will um
15:31 proteins involved in things like attachment and . Here's a picture there it is
15:39 it. OK? Looks like OK. So not uncommon uh what
15:44 enveloped viruses look like. So the is the envelope that would have come
15:49 a host cell, it has right? And um so things like
15:55 proteins help to uh uh bind the of the cell membrane of the host
16:00 get entry uh attachment protein also for initially to the cell. Um And
16:07 this is what's gonna recognize specific host proteins and and be able to gain
16:13 . Um These, we'll talk about as well. So uh here is
16:22 the genome, of course that minus a strand and then proteins stuck to
16:26 . OK. That's one way to if you will a genome,
16:32 That's thinking of that as one type capsid if you will. OK.
16:36 And again, we'll talk about that uh I use a COVID as the
16:40 for this. OK? Because it a similar one. So does the
16:43 virus similar in nature. So uh , so you know, there are
16:49 um the similar features that you can for any virus, right? In
16:52 of where it's found uh many of transmission um structure. OK. And
17:00 if you look back at uh let's answer this question first. Take
17:05 breath, take uh let's get our here. Uh So a naked
17:11 right? So we're gonna talk about structure. OK? You got a
17:15 virus, you have another type of . OK? So a naked virus
17:19 lacking or missing what? OK. . So, well, let's see
17:33 you get, remember, test taking . If you don't see the right
17:46 , then you know what to right? If you don't see the
17:50 answer, you know what to OK. Now, sure.
18:06 So with uh does that hint I 99%? Got it right.
18:16 Mm Nope. OK. A naked is missing, what's it missing
18:27 right? Missing an envelope. Uh So e no, the above
18:31 it's missing an envelope. OK. . So uh because all viruses viruses
18:44 a caption, right? Captured in , that's the basic structure of any
18:49 . Then you can have other, course, other stuff with that.
18:52 every virus has that basic structure captured genome. OK. So um all
18:59 . So kind of classifying viruses based structures of symmetrical, of course,
19:05 uh it can be these geometric shapes see here at Cooed 20 sided.
19:12 . Um they can be in this , they can be in a filamentous
19:16 like a string, so to Um the viral proteins here making up
19:21 cap and those are gonna be viral , not, not coming from the
19:25 , the capsid part. And uh know, there they can be 3
19:30 4, maybe five different variations that put together in a particular configuration um
19:37 saves on, you know, genome So that not every face here if
19:41 will is a different protein because the viruses have a small genome,
19:46 size, small genome. So they to be efficient, you know,
19:49 the genes they have and what they're , right? So they take,
19:53 know, a a few forms of types, the cat proteins and put
19:57 together, OK? In these OK. So uh so envelope
20:03 right? So I have in addition the caption, the envelope of surrounding
20:08 . So that that will come as we'll see uh when the viral
20:12 cycle is going on and the virus the host, um it'll, it'll
20:17 with that, that membrane from the wrapped around it and that becomes the
20:22 . OK. And uh of there'll be viral proteins inserted here um
20:29 various functions as we just saw for to a host, um maybe to
20:34 get it into the host, um have enzyme activities of different types.
20:41 it just depends. OK. Um like protein spikes, although we see
20:46 here, they, they too are feature of non enlo viruses. They
20:52 viruses. They can have that as . Ok. Um And so these
20:57 are what are the, what they what buy us to a host self
21:04 protein is the recognition a aspect of . Ok. Um OK. So
21:12 viruses, right? Like Ebola is flu virus, the back a mosaic
21:16 we talked about before. Um and even it can be wrapped inside of
21:22 capture like this. OK. And um now tail viruses, uh these
21:29 kind of a combination, right? used to be cause called asymmetric.
21:35 still may be uh in some just depends on the book. But
21:39 know, they're asymmetric because they have different parts. So you see the
21:43 CAPD form here, OK. That a genome. But then it's got
21:48 other stuff, right? So it's this uh tail sheath, they call
21:53 um the fibers, these are parts of recognition, this will sit on
21:58 of the host. OK. And this is very typical for uh bacterial
22:04 . OK. And so uh this be perhaps a host cell sitting here
22:10 these tail fiber ends would recognize specific protein. That's how it sits sticks
22:17 it. Um This would actually this compresses this part here. It that's
22:24 it shoots the genome into the host OK. That would be the
22:31 So, and so it's basically a of like pressure, a pressure,
22:35 a syringe and pressure shoots that genome the cell. That's very common for
22:40 bacterial viruses. It's, I can't of a case for a bacterial
22:45 The whole thing goes into a It's just a genome. Ok.
22:49 animal viruses, they, they very do do that. Ok.
22:54 um, now what they call asymmetrical . So, influenza and this is
23:01 these are asymmetric because you're looking at and go, well, that's just
23:04 , it's a ball. How is ? Not symmetrical? Well, it's
23:08 it actually has kind of a blobby to it. OK. And um
23:14 you look at electron micrograph, you'll see that. And uh they
23:19 have flu virus as an example. have uh the uh they have not
23:25 just a CAPD, OK. But don't have that typical geometric looking CAPD
23:32 , right? 20 sided form. , it's more uh you know,
23:37 can kind of shape into a oval round or various forms. OK.
23:43 also has um um protein stuck to genome, right? So that's what
23:49 want to mention next. OK. here is uh Coronavirus. OK.
23:57 , very similar in terms of um it looks, looks kind of like
24:02 two virus we just saw. So it has like a similar pro
24:06 proteins sticking out. Um Here's the in red and it has a
24:12 And so the genome is coated, can't really see it here. Uh
24:18 like a blue line on top of genome and that's what we call nucleocapsid
24:24 , right? So here's kind of , you know, 111 form,
24:28 ? A that 20 sided shape, ? And the CAPD and the genome
24:33 of it. Here's the envelope. Here's another way to do it is
24:37 have these nuo captured proteins, all , that stick to the genome.
24:46 . And so that's kind of a way to another way to make a
24:51 if you will, right, have proteins just binding right on top of
24:55 genome. OK? And so flu do that COVID and others do
25:01 OK? So just it's just just a variation and structure.
25:06 Um OK. Uh Let's see. . So any questions about structure?
25:18 . But I don't see your You can shout at me just no
25:20 , please. OK. Um All . You know, so I just
25:24 this in here just to kind of you an idea of, well,
25:27 do they code for? What are sizes? Right. So, you
25:30 , we just saw that viro viruses vary in size. There's a size
25:35 of ranges. So obviously, then they can accommodate bigger virus, bigger
25:40 typically. OK. Um How Well, this is kind of the
25:45 end, right? 100 genes, , small viruses. 5 to
25:50 Ok. Uh So the Zika um, which, um, made
25:57 news maybe five years ago, um uh pregnant mothers. It would cause
26:03 in, in the newborn, fatal disease typically. Uh, but
26:10 , it's what we call a non . So we'll see what a
26:14 um, chromosome is. One that's just kind of broken up in the
26:19 . Flu virus has a segmented segmented , like I think 88 segments is
26:24 whole chromosome. OK. And so uh so this is about 10,000
26:30 And that's kind of an average size most viruses, but they do have
26:35 proteins that they produce for their replication . OK. Um Goal G prote
26:43 kind of helps with its assembly and out of the cell, for
26:48 Um And so, you know, will have specific viral enzymes they need
26:53 in order to, you know, you remember what that virus has to
26:56 , it has to bind to a host cell has to get into
26:59 host cell. It has to um then migrate to the part of the
27:04 where it will replicate itself. So gonna need various parts for each part
27:09 that infection cycle. OK. Um here's a flu virus, eight
27:14 So it's what we call a segmented . And um uh and so the
27:20 thing about viruses is OK. Um than so if you have a viral
27:27 , right? So this is take one, for example, flu virus
27:30 , OK. You can have more , you know, more than one
27:33 can infect the same cell. And so in doing so, uh
27:39 genomes can recombine. So especially with flu virus that has a segmented
27:46 these parts can recombine. OK? so this uh what these color,
27:54 colored segments represent. OK. Are , the origins of that chromosome.
28:01 in H three N two flu the uh red uh I believe I'm
28:08 , the yellow, I think it's like a bird from birds. So
28:12 flu flu has its origins in uh birds like ducks and geese, um
28:19 into domestic ducks, geese and OK. So like an a an
28:25 portion of this, right, avian , they also have pig swine,
28:31 parts. Uh chromosome parts can also a part of this as well.
28:35 the virus originated, we think in uh wild aquatic fowl birds then
28:44 to domestic fowl, I eat chickens whatnot and then to pigs, uh
28:50 pigs and then, OK. So recombination is occurring now and then to
28:54 . And so you can have a virus that has its, its viral
28:58 DNA origins or, or sorry genome of multiple types of, of
29:03 of its pack from its past, ? The host that it used to
29:07 , right? You all combined. so um and so the, this
29:13 N number, you know, I'm not gonna test you on it
29:16 just you always seeds associated with the virus. OK. So the H
29:21 N is refer to specific proteins on surface uh over here. So uh
29:28 see a kind of a small one is kind of a diamond shape
29:31 one's a circle, right? And can't remember, oh, you can
29:35 it here as well. These types these types. So one is the
29:39 and one is the end. Uh That's a bad end. Let
29:43 try a different one. So H N so it just refers to
29:48 a, the, the flu viral type spike on, on the
29:53 The, the uh the H I is the one that enables it to
30:01 to a host. And the end is what enables it to exit the
30:04 . And so they're important for its cycle obviously. So, um but
30:09 can have different variations of the H N and that's how you get a
30:13 N two and so on and so . OK. So um OK.
30:19 so you know, like many like most viruses, particularly RN A
30:25 , um mutate at a fairly fast , in fact, so they can
30:31 uh into forms. Um you from one, have one flu season
30:36 the next, right? We all that you get a flu shot this
30:39 . It's not, you could have effect at all in the following
30:42 So you have to keep, because constantly evolve and change. Right.
30:44 so obviously you have to keep making vaccines each season to keep up with
30:49 . Right. And even then it's 100% successful, right? It
30:54 So, uh because you can, know that the virus changes from season
30:59 seafood, but you can't predict exactly gonna be the most prevalent form.
31:04 that's why vaccines can kind of you know, good some years,
31:08 not so good. The next we of sometimes just nail, nail it
31:12 ? 11 season, but not so the next. So that's why you
31:14 have a lot of variation uh in terms of flu shot effectiveness.
31:20 . Um I don't know what the are in the current vaccine.
31:25 But uh anyway, so uh just , you know, COVID has evolved
31:32 , into different forms. So would somebody first started out with,
31:35 What was the, uh I forget they call the first version, but
31:38 it became Omo Cron and now it's different version now. So, you
31:43 , the viruses evolved like, like else. OK. But they can
31:47 do it a little bit faster because mutates so quickly and, and um
31:52 contributes to this. OK. go ahead. Uh those two
32:03 Um OK. All Right. So good question. So the reassortment between
32:10 . So, uh, so the thing to mention is that, so
32:14 just take the cell infected with a virus. Ok. So the flu
32:18 that come out of there call it flu virus progeny, right. Each
32:23 those can be, there's gonna be dissimilarity among those. Like they're not
32:27 be clones. And so, yeah, so they infect the
32:30 You can have two flu viruses that genetically dissimilar affecting it and then you
32:35 Yeah. Yeah. Right. So. Right. And that's true
32:38 uh I'm gonna say true for any that infects the, the babies that
32:42 out are not gonna be all There'll be, there'll be some dissimilarity
32:46 them. Yeah. Yeah. Any questions? OK. Um All
32:54 Let's look at this question here. we're gonna talk about prions and
32:57 So is the before and after. if you're not sure you get the
33:01 shot here in a few minutes. . Um So while you're reading that
33:09 um to mention, so there's, viruses, Viro and prion. So
33:17 groups, right? So a prion not a virus, a viro is
33:24 a virus. Ok? So when see virus, you go OK,
33:28 minimum, it's got a protein coat and a genome inside, right?
33:34 maybe has some other stuff depending on virus type. OK. So a
33:39 or prion does not fit that So that's why we call them virus
33:45 prions, not viruses. OK. just remember that, right? So
33:50 prion has its own definition structure. as a thyroid, right? So
33:56 just them as 33 things. Um OK. To all right,
34:24 count down from 18. OK. see what we got here.
34:47 let me take a snapshot. We'll move on and come back to
34:55 in a little bit. OK. . So I, I'll say at
35:03 beginning, so thyroids are basically infectious A, it's all, they are
35:11 , a molecule that can infect prion an infectious protein. So RN A
35:19 , a a thyroid uh protein, ? That's, that's essentially the structure
35:26 both. OK. So um thyroids far as I know, do not
35:34 humans. OK. Uh They're strictly problem for plants of different types.
35:43 . And among those are plants that crops we eat. Uh potato is
35:49 of those affected by, by um things. OK. So uh as
35:56 , it's this is the essentially it's an RN A molecule.
36:00 So you recall RN A molecules are , are not double stranded like
36:06 they're single strand, but they can secondary structure, right? They can
36:10 chain, single chain can fold on , right? It just all uh
36:14 UGC based, right? And so kind of the secondary structure, two
36:21 of one type. Uh Here, is uh the pota potato spindle
36:27 bro. OK. So again, secondary structure. So knowing what you
36:32 about RN A molecules, right? can um they can have kinetic
36:39 right? They can be enzymes. . So um they are rather
36:47 So for is not that big. so the uh to recall in protein
36:55 , um the ribosome when you, it's sizing proteins, right? The
37:02 an RN A in the ribosome that catalyzes the peptide bond formation,
37:06 So that's one example. So there's other RNAs that can have enzyme
37:11 OK. And apparently what this does the plant it infects OK, is
37:20 with gene expression. So you can , for example, let's say plant
37:27 , OK? Plant MRN A, . And there may be some homology
37:34 the viro, right. RN OK. Such that it then interferes
37:45 the ability to be is a OK. So it interferes with the
37:52 of the ribosome to go to continue the the piece of thyroid DNA that's
38:00 to the transcript is blocking it from any further. So that's how it
38:03 affect um expression. OK. The , you know, it it gets
38:09 the post, you know R right? And then copies its genome
38:14 way. OK. Um how it's from plant to plant, I don't
38:21 that that's known. OK. Um aren't that easy to just get
38:28 right? So very often plant kind of insects are often the kind
38:35 the, the, the mechanism for viruses get into them. But,
38:41 , among others. So it, I'm not sure, uh, it's
38:45 exactly with these viro, the transmissibility plants. But, but certainly it
38:50 an economic impact because they have devastated times, uh, these potato plant
38:56 in various years. So, it is significant in terms of
39:01 Ok. But again, no humans , it doesn't cause any kind of
39:05 disease that we're aware of. Um I have essentially, but these
39:10 infectious aren't a molecule. Ok. that's, you know, small
39:16 interferes with expression in the host. that's kind of its thing.
39:23 Uh Prions under their hand. Um These are, you're probably more
39:31 of this and certainly back in the , there was a scare, so
39:36 speak. Uh not really here in States more so in uh Great
39:41 Um uh and infected some infected cattle into the system. Um And uh
39:49 don't know of human fatalities. Uh thing about this disease. So it
39:56 like different names depending on um the of what you're looking at. So
40:01 has different and I think it was in, in sheep, in
40:05 Uh So scrapey is the form that comes from the sheep. Uh Jacob
40:12 a form found humans. Um So cat, right? So this is
40:17 where you likely have your familiarity of this before. And so obviously infected
40:24 , uh uh, that are you know, you can, you
40:27 , consume the, the contaminated meat presumably acquire one of these prions and
40:33 affect you. The thing is in human, it is a very slow
40:39 disease. Ok. Um, and , you don't even know you have
40:45 . And I think when you do you have it, it's likely too
40:47 because there's really no, no cure it. OK? And when I
40:51 a long time, I mean like , 20 years or more.
40:56 So, and of course, it itself eventually as neurological issues because it
41:01 the brain. OK. And so term here, sponge of form
41:09 OK. Spongy literally the the brain literally turns into a spongy tissue.
41:15 ? Because holes are created as the are basically destroying or Trion, excuse
41:20 , are destroying nerve cells. And so it's all the, the
41:28 and air quotes of this thing is through um uh binding to a normal
41:37 of the protein and the binding induces the disease form. OK. So
41:45 so what does the, so that mean that we have a normal form
41:51 this protein? And we do, still don't know what the function of
41:56 is. So we accumulate this protein our, in the membranes of our
42:02 cells. OK. Although it's found many other cell types but the um
42:10 the uh function has been, they has something to do with copper
42:15 It's strange. Um there's still some on it but we do know that
42:20 this abnormal form binds to the normal , it changes it into the abnormal
42:27 , right? So much like OK. So, yeah, you
42:32 the prion protein through um through, know, eating contaminated meat.
42:40 And um and again, the binding , a normal form will induce
42:48 OK. And so, uh and see kind of a chain reaction occurring
42:54 , OK. Accumulating, basically accumulating prime proteins as this disease progresses and
43:01 accumulation and it reaches a point where quantity of the quantities of these are
43:07 much in a cell that it basically the cell and destroys the cell
43:12 OK. Uh In fact, these can um combined together in long chains
43:20 almost and that can kind of affect cell. And so, um apparently
43:25 also very resistant the chemicals uh Um and, and uh presumably because
43:34 its way it folds up. It what is what provides this resistance.
43:39 the um so here's brain tissue of , probably an animal, I
43:46 but it's uh it, when it the uh neurons, it leaves behind
43:52 plaques or holes in the tissue. so these accumulate, that's why they
43:57 this like sponge spongy texture to the . OK. Obviously, you don't
44:02 to have holes in your brain Ok? Not a, not a
44:06 thing. And so, um and is kind of just a different picture
44:10 this. So you see the red the abnormal or the prion forms that
44:16 in the cell. This would be neuron, of course. Um And
44:21 uh the degree went out of normal and so, accumulating these leads to
44:25 death of the cell. Um and can migrate to other cells and
44:30 and then begin to destroy them. again, it's a very gradually progressing
44:35 . Uh But ultimately, it, ends in death. But in here
44:39 the States, the number of, mean, I haven't, I've been
44:42 aware of a case of this United for several years. OK.
44:48 um no, nothing you need to aware of. It's just um or
44:51 be afraid of rather. Um but unique in terms of, it's
44:55 it's a protein that's infectious. it's all it is a protein.
44:59 . Um And the way it so to speak is kind of strange
45:03 well. You don't see this in anything else. Um OK. Let's
45:11 at it at the question again. . So let's see. We got
45:50 . 15 years. I Yeah. . All right. So DNF,
46:22 were we at before? Yeah, was a and D wasn't, let's
46:29 it was fine. How are Was 1 33 1 33. It
46:46 1 30 3d and 1 22. So that's what roughly 40 something people
46:55 their minds more or less more. The correct answer is D OK.
47:03 , uh they do require thyroids require plumes primes don't require any plym.
47:11 just a protein, right? um so yeah, any questions about
47:18 ? I always cry on. All right. So you only gotta
47:23 about bros if you're a potato uh a few other plants. Pipes.
47:29 OK. So here's another question, ? So in reference to RN A
47:37 , OK. Depending on the particular A virus type, its genome could
47:44 used as a template for what? . For the Coronavirus, there is
47:52 type, there are other types. ? The OK. Counting down.
48:30 , sorry, I am 10 9 . Yeah. Yeah. It's gonna
48:46 all the above, all the So, uh so with our new
48:55 , um the template for translation would the plus RN A MRN A
49:06 M minus RN A. The virus synthesis is retrovirus. Bye.
49:17 HIV. Um So retrovirus, uh this genome is for copying the
49:23 OK. So, but we'll get that later. Um So that's,
49:29 why, you know, if you the sense antisense thing, we'll get
49:34 that in a little bit uh Uh Right now. And so classifying
49:41 , right? So, um there a question like last time you
49:46 you can look at different viral Is it, what's the genome
49:52 What's the um does it have a , I mean, does it have
49:55 envelope or not? Um um what of proteins are on it? You
50:02 , there's a number of things you pick to, to classify them.
50:05 uh generally the, the way it's is through what's called a Baltimore
50:12 So it both involves what's the type genome it does it have and then
50:17 does it get to, what's the it takes to get to uh the
50:22 A, right? Because that's it, because obviously that, that
50:27 is what enables it to produce viral , right? Which of course,
50:31 essential if it's going to be So, OK. So uh for
50:36 viruses, that's pretty we, we get that because that's what we
50:41 we're not DNA viruses, but we DNA in our cells, right?
50:45 so um we basically use um RN climes to transcribe our uh antisense strand
50:53 make a sense strand, right? uh similarly group one and two,
50:57 are DNA viruses, uh the same . OK, copying the negative strand
51:02 DNA to make the positive strand of A. So remember this here,
51:08 . This box right here that the MR A, the one that
51:14 going to be translated, that's the strand, that's the um sense
51:21 OK. So um so if we at um the RN A group,
51:30 groups of RN A viruses, Um You may look at it how
51:36 replicates and go, OK. This weird. Um It's like it's two
51:42 forward, one step back, kind a thing. So, uh but
51:45 , there's a reason why, so all, it all just relates to
51:49 you um the language you use when about nucleic acids, right? So
51:56 got here is here is RN right? And we know that because
52:00 got UYS here, right? But plus minus relationship, right? It's
52:07 same whether it's DNA, DNA, ? DNA RN A Rnaraarn A all
52:20 can see here in the example, ? Because you're, you're, you
52:25 , they all it's all the same , right? Because a a nucleic
52:29 polymer has a five prime end and three prime, right? And when
52:35 copy one strength, they're making a friend as you see there,
52:40 And the relationship with both of those plus and minus, OK. So
52:46 the plus strand is the one containing coding information. OK? And so
52:51 wanna make a, a copy of , right? Uh uh to,
52:56 be able to translate and make OK. So um so easy enough
53:04 understand with us because we have we copy our, we copy the
53:09 strand because that gives us the plus , right? And we can then
53:15 an RN A to translate. But an RN A virus depending on
53:19 type will have to go through, know, a couple of steps.
53:24 . It's not as straightforward, let's . Ok. And so the other
53:28 is, um, we have an A plumb race as does you
53:36 all their life forms. Ok. , which is what we call an
53:42 A dependent, I'm sorry, just it up. D as in
53:48 DNA, dependent RN A plum. RRN plym only copy R DNA,
53:55 ? Our plym don't copy RN OK. So an RN A virus
54:02 group three, group four have a RN A polymerase type that can transcribe
54:09 genome. OK? That's what this is. OK? And so uh
54:15 a viral enzyme. OK? Uh , because it stands for RN A
54:21 on it from us. We don't that. We don't have a need
54:23 that. We don't copy our RNAs that. OK. So uh but
54:29 a virus that's this genome, it's have to have a way to have
54:31 have a way to copy it. . So um so for the double
54:37 RN A virus that's pretty straightforward because has both a plus and a minus
54:42 , you just copy the minus strand get the plus, right?
54:45 remember that, right? If you A plus, you make a
54:49 you copy a minus, you make plus, right? You never are
54:51 not able to copy a plus into plus. It doesn't, that it
54:57 the, the DNA nu-, the acid rules if you will.
55:02 It doesn't happen. So, because the complimentary strands are complementary to each
55:08 , not identical to each other. . That's why you have the plus
55:12 relationship. OK. So you can't a plus into a plus or minus
55:16 a minus. Right. It would easy to do that, of
55:19 but it doesn't work that way. ? So that's why you see here
55:24 these two groups, right? The stranded RN A viruses, OK.
55:30 we go here first, right? up plus to a minus and you're
55:36 OK. Again, why is it that? Right? Is that it
55:40 have a need for minus strand? , what's, what's up with
55:42 Well, again, that's when you , you have to make um one
55:48 these, right? So about quantity . So you have to remember what's
55:52 end game here? The end game to make lots of viral particles.
55:55 if one's coming in, it's more and works more quickly if you can
56:01 multiple copies, right? And then , then for those multiple copies,
56:05 lots of protein. OK. So , but also, right, if
56:11 going in, for example, with group for with this genome,
56:15 So all if it's um that viral with A plus RN A genome is
56:22 the end game is make lots of particles that have a plus genome because
56:26 the kind of virus I am. . So it's all about quantities,
56:30 ? So uh in order to make copies of this, right, you
56:37 to go through this path to OK? Because again, yeah,
56:41 would be super easy to take that genome and make lots of pluses from
56:45 , right? Doesn't work that You have to go through the plus
56:48 plus thing, right? And so AAA plym enables that. OK?
56:53 you make lots of these, which then produce lots of these,
57:00 can be used for both translation and shove into a assembling viral particle,
57:08 ? Um the minus RN A right? So copy that directly into
57:16 transcribe it to MRN A plus, from that. But the problem is
57:23 have to make more copies of right? Because again, in
57:28 right, gonna make lots of viral and then you have to contain the
57:31 genome. That's the kind of virus is. So we have to go
57:35 back this route to do that. ? Is to make more right into
57:42 Mr A because these are what's gonna stuffed into the viral particles,
57:49 Because that's kind of genome they you have to make a lot of
57:52 of that. OK? So for, for the route five,
57:56 minus to plus to minus right. pluses are used for translation like
58:02 The minus forms are what we should into the assembling particles, right?
58:07 plus route four plus RN A viruses plus to minus. Now, we're
58:14 make a lots of minuses because that's make us lots of plus strands that
58:18 can then rub into the capsules, ? So it's all about making lots
58:22 particles. OK? Um And so , the, the one that's completely
58:28 is retrovirus, right? So uh has reverse transcript tapes. OK.
58:33 that enables it to form a minus does actually then uses host, you
58:41 to make the second strand. And , and it does that because it
58:45 its life cycle is to integrate into host, right? And if you're
58:49 animal cell, uh and it infects , then it better have DNA because
58:57 can't, you can't insert RN A DNA, you know, you have
59:00 put DNA in there. So that's it goes into that form.
59:04 And so, um and then it just use at this point, it's
59:10 a host, host and host. in the first step host, um
59:22 A plum and then here host a OK. So with this brain,
59:27 party is reverse transcript cases that's a viral enzyme. OK. So,
59:33 know, we're gonna go through these in a little, little more detail
59:38 time. But um this is kind , and I just want to plant
59:41 seed in your head in terms of go, OK. Minus the plus
59:45 minus, plus the minus the plus , blah, blah. Right.
59:48 I'm trying to, you know, , we'll go through it again next
59:51 . But that's the logic always think here's what's infecting, what are we
59:56 at the end? We're making more with more stuff like proteins,
60:01 et cetera. OK. Um So one, don't, don't memorize this
60:07 . OK. Um Just give me idea of, here's the groups,
60:12 some representative types. I'm not gonna you on. OK. Which group
60:16 this virus? In blah, blah. OK. But um you
60:20 , you're gonna recognize some of of course, so uh Papilloma
60:25 right? Uh probably one of the common uh STES uh is this one
60:33 uh Herpes virus, we're familiar with one. The uh oops, the
60:42 we really are familiar with uh in of RN A viruses, right?
60:47 group uh right here contains like the and the COVID and the West uh
60:54 , my measles mumps, et So lots, lots of things we're
60:57 with and so too in the plus the plus uh side. And so
61:03 sorry, I got put Coronavirus in wrong group. Air plus a virus
61:07 . Uh West Nile that's endemic in part of the country. Uh Eastern
61:13 , uh Eastern uh Texas, Western . Uh of course, air by
61:20 . Um There's always a few cases that here in Houston uh every
61:25 Um And so the one odd ball a retrovirus is one of the oddballs
61:30 this group at the bottom. So have a, they also have a
61:34 of reverse transcript base. Um But kind of does an opposite thing.
61:38 they have the DNA genome, But they copy into a plus RN
61:46 . Um And then they have their transcript phase copies that into DNA.
61:52 . And so it's um it's a kind of a backwards retrovirus if
61:58 will, I guess, you but that, that's how it
62:01 So it um uh in order to, to provide genome copies to
62:07 viral particles, it has to take RN A and copy that back into
62:12 . OK? Per virus. We it OK. Um OK. Is
62:21 any question? So if you, I said this part here, if
62:26 still kind of OK. Uh When get into a viruses in part
62:34 we'll, we'll go through this OK. So, um you
62:37 it's kind of one of the things just gotta think about. But if
62:39 do think about it in terms you know, what's, you
62:42 here is the virus affecting what's the game, right? Make lots of
62:46 particles and you need lots of stuff do that. Like proteins,
62:50 OK. So um so if you at um here, so this is
62:57 of summarizing the structure OK? Of . And um uh so as you
63:04 through, so definition, right? cap type um I hit that geometric
63:12 or is it the filamentous form? you don't type their uh make their
63:17 virus? Right? Um Other, know, glycoprotein spikes specific proteins.
63:24 I mean, it's not necessarily a , I mean, it's a
63:26 I don't know. I have. , no there but um the uh
63:32 is. Yes. OK. Um just, you know, what's the
63:37 ? Is it? Uh uh what's type? So, um anyway,
63:43 the um so we're gonna, I'm push this a little bit forward
63:50 OK. Probably wait till maybe next Tuesday. That may be, that
63:55 be the last thing to finish up . Um uh So we can get
64:01 little bit into some of the life . I just wanna go into just
64:04 bacterial virus life cycle. That's kind the first one we use because
64:09 they're not as complicated as an animal life cycle. OK. Uh Which
64:15 sense, right? Because animal in fact, your car out cells
64:19 are more complicated protic cells simpler by . OK. So, um before
64:28 go on to any questions, OK. All right. Yeah.
64:37 . I probably didn't. So uh appreciate it. Not very.
64:50 Yeah. Uh I don't think so whether it's broader, narrow tropism or
64:58 broader, narrow uh host range, all has to do with the molecules
65:02 are on the surface and what it . So I have the size is
65:06 really gonna make a difference there. yes, it does. It have
65:09 molecules that recognize the particular tissue type that's, that's what, that's what
65:15 . Yeah. Any other questions? . OK. So, all
65:22 So this is, this is gonna a bit of a, a
65:25 But um so as you go, part two is really all about life
65:29 of a virus. OK. And start with uh bacterial viruses or bacterial
65:35 , we call it and then move animal viruses. OK? And
65:40 you know, again, there's gonna variations from type to type but you
65:46 what they all have in common is uh recognition. So it begins and
65:50 there involving different types of protein hosting, hosting virus. Uh the
65:57 genome entry can be in different So um does the whole just does
66:05 the genome enter the cell or does of the uh virus structure enter as
66:11 ? Caps it, for example? . Um But of course, uh
66:17 to both is gonna be or common all viruses is the, you
66:21 copying of genome of viral proteins and that happen, right? And assembly
66:27 in the viral particles. OK. then um and then exiting the
66:32 OK. And then obviously, they go on to infect more cells.
66:37 . So this can happen, especially bacterial uh bacterial viruses. This this
66:42 happen rather quickly, right? Because grow fast and viruses can infect and
66:48 very quickly infect uh many more bacterial . And so, uh and so
66:54 see that because the first things we at uh are is light, we
66:59 light stage and lio. OK. let's look at this question here.
67:04 . So the lytic age versus lysogenic . OK. They have a couple
67:10 few differences there. OK. So um user are not part of the
67:18 cycle of a lighting lighting? That. Mhm. Right.
68:09 Let's count down 10. Hm. . So the two that are,
68:28 are not part of the psycho R . What's not part of the
68:36 D for sure because light pha are P pages. OK. Tempered pha
68:42 lysogenic P pages. OK. And the other one that's not part of
68:46 cycle. E yeah, the entire . So that's a general rule for
68:52 viruses. They don't only the genome in the whole, the whole thing
68:58 . OK. Um So in um at bacterial phage life cycles, so
69:06 , specific for bacterial cells, um uh the light types um can produce
69:16 to 100 203 100 P per cell killing the cell. Um What we
69:25 t even PS T two, T T six, et cetera. Um
69:30 so the um the um lysogenic so we call them temperate,
69:38 Because they can kind of so to , run hot and cold,
69:42 They can, um they part of life cycle is to be integrated to
69:46 host chromosome. OK. And um then they exit that cycle if they're
69:54 replicate into viral particles. So they go back and forth between a lighting
69:58 and a and a light cycle. of it as kind of a or
70:02 , think of it as kind of dormant cycle if you will.
70:06 And so, um it's what we a prophage when they integrate into the
70:11 chromosome. OK. But if it's to replicate, it's gonna have to
70:16 back into the lighting. OK? the only way to, to
70:20 OK. So it kind of switches both. OK? And there's
70:23 different triggers for that. OK. You know, stress like radiation
70:29 or excessive temperature. These are things can trigger the uh going out of
70:35 into fighting cycle. OK. first, so we're kind of gonna
70:41 two birds with one stone here. . So uh light cycle first.
70:49 . So of course, it begins recognizing host genome enters the cell and
70:55 very quickly, part of the process to break down the host genome.
71:01 It'll use recycle those parts. Uh its own use. Um and then
71:08 begin to synthesize, you know, viral proteins, uh copy genome,
71:15 everything together, OK? And then out of the cell, right?
71:20 not uncommon for many of these to like lysozyme, lysozyme breaks down cell
71:25 material um that coupled with just the sheer numbers of viral particles being made
71:34 overwhelms the cell and kills it. ? But that's a lot 200 to
71:39 per cell, right? And very they go to infect on the
71:42 So, you know, we can an E coli one mil of e
71:46 culture and a drop of phage. in 30 minutes, the whole thing
71:50 like water because everything's been killed and know, very quickly. So,
71:56 that's, that's the nature of a , a light phage period, in
72:01 , make viral particles kill cell. , that's the cycle of a lighting
72:05 a lighting virus. OK. this cycle will be a part of
72:13 . So those, so lambda P the one that can carry this
72:17 And so uh so it will have part of its cycle, the formation
72:25 a prophage. OK. And so may or may not be able to
72:29 it, but in the, in chromosome is there's a purplish area and
72:34 the prophage. OK. So as cell replicates, right, um it's
72:41 detrimental to the health of the cell the host it can just keep
72:45 grows, grows multiplies. Um uh it's basically kind of like a ticking
72:51 bomb, right? So at some , um it will um convert to
72:57 to light cycle, right? Because the way for it to make new
73:00 particles, right? So need to cycle. Um And so very often
73:05 can be an environmental stress of some . Uh So best to go into
73:12 light cycle and make the environment particles be, don't let the host cell
73:17 killed by the stress, right? it's lack of nutrients or radiation or
73:24 , right? You don't wanna get with the ship, you want to
73:26 out of there first and make your particles, then the cell can
73:31 right? But then you go you've made viral particles, in
73:33 more cells, right? So, so again, it's, it's,
73:37 the the health of the cell if will typically dictates um you know how
73:43 it stays in misogyny versus going to cycle. OK. And, and
73:47 virus, you don't go into but the the virus is producing proteins
73:53 kind of monitor the situation. Um They interact with the viral prophage
74:00 in there and determine what you're gonna , translate or whatever uh based on
74:07 certain molecules in the in the host . That kind of are an indicator
74:12 , of health, whether it's you know, um A TP ad
74:17 ratio is one of those, That's kind of a state of the
74:19 of the cell. We have a low A TP ratio. Uh the
74:24 of A TP to AD P that oh the cells that's probably not very
74:28 cell, right? Typically you have excess of A TP or AD P
74:33 you're a healthy cell. Ok? you have nutrients coming in and you're
74:37 energy and so on and so So there's, there's different markers that
74:40 be used to kind of gauge and what the virus is doing to
74:44 Oh, stay in iso, let's to light cycle. Which kind of
74:47 back and forth. Ok. any questions about that? Yeah,
74:58 , right. Oh, there yeah, I guess if we're gonna
75:06 that, but it's a lag stationary death that certainly during a log
75:12 the log phase might be where it's pop out. Yeah. Your
75:18 Good lab. I'm gonna see Well, those of you that can
75:22 it. I'll see you.
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