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BIOL 2320_Microbiology for Non-Science Majors - 10_11_22_Lecture
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00:23 Okay. Yeah. Okay. okay, testing. Let me raise
00:39 microphone here a bit thing. That's better. Okay. Um,
00:47 those of you that are interested. bad news 6 2 to Seattle baseball
00:55 Astros mariner 62 if that's your Okay. I realize not everybody,
01:03 everybody's thing. Okay. So, , okay, usual stuff.
01:10 So, um, so remember, this week's quiz is a unit
01:17 Right? So it's one of those , a little bit longer quizzes,
01:21 more comprehensive. So cover 78, and 12, which will do,
01:29 , At least part of 12. . So we'll probably get through most
01:34 that I think, but probably have leftover. But whatever we don't
01:39 there won't be questions on the but it probably gets through part of
01:43 . Um, let's see mastering due next monday. So today we're gonna
01:51 up at least get close to finishing most of the viral life cycle
01:57 Okay, so, um, The . So thinking about it because I
02:04 that the uh, chapter 12 will looking at like fungi allergy, et
02:09 . That is not that long. it's conceivable that we could start.
02:19 next week, of course we're starting three. And so it's gonna
02:26 we might start that on on but I'll let you know, let
02:31 know. Um, okay, so do a little bit of a recap
02:38 we essentially finished part one. So kind of do this virus viruses viruses
02:45 prions chapter in like two parts part . I think we pretty much
02:51 But this is kind of rehash a of things. So the so we
02:56 with like what's the definition of a ? Right. Remember it's it's a
03:00 not a cell. Okay. It have all the features we think of
03:05 we think of a cell. There's really no metabolism. There is
03:13 uh obviously he's a host because it have a lot of functions needs a
03:19 . Okay so it relies on the for a lot of things obviously to
03:24 . So um the basic structure of virus. Okay um at the most
03:31 all viruses have a genome of some R. And D. N.
03:34 . Uh then surround that with a caps. It okay we get different
03:41 of course. Right. Can be an envelope around it possibly that will
03:47 it from the it will acquire it the host. Um And of course
03:52 specific proteins that we some proteins associated different parts of the infection cycle attachment
03:59 a host. These kind of Okay so um and so the terms
04:06 it was envelope, it's a naked , it doesn't have the envelope around
04:09 . Okay so you should be familiar these basic features um and then in
04:16 of lifecycle. Okay so the sequence events itself and you know basically all
04:26 kind of followed basically follow this It's where there will be different different
04:31 at certain points as we'll see Um but you know it certainly begins
04:36 ends with kind of recognize the So the events on the surface of
04:41 virus and the host cell recognizing molecules . And then um then of course
04:48 next step is to get the genome the viral genome because that's what needs
04:53 be translated into viral proteins. Then have the package copies of genomes.
04:58 eventually getting to uh intact virus particles then make it the host.
05:04 And again and each of these steps can be different variations and we'll see
05:11 as we go through these cycles. we went through last time again I
05:18 simple simple can be relative but we're about bacterial viruses and our bacteria viruses
05:24 fage. Right so you see the fade or bacterial fage bacteria viruses and
05:30 we tend to call these more simpler cycles simply because they're infecting these
05:36 In fact. Procure erotic cells. . Which compared to eukaryotic cell less
05:41 . Right? So um the but sequence of events is not that much
05:47 and even have attachment. Right so have what's called a little page and
05:52 the second year less a genic right analytics page is um basically it's it's
05:58 is seacoast um inter host make lots virus particles kill host and then continue
06:06 process. Okay. Um and so doing so we have these basic steps
06:11 attachment penetration is entry of the So one of the things about in
06:16 to animal viruses we're talking about Material viruses generally only the genome
06:23 Nothing else. Everything else stays outside . Okay. Um in the writing
06:29 they of course will degrade the host . N. A. Then begin
06:33 um direct synthesis of its own viral . Make copies of genome, assemble
06:41 uh producing mature fades and then exit host. Okay basically killing it.
06:48 so are also called virulent page. . They're gonna kill the host cell
06:55 these can go on and infect more more cells. So uh echoes
07:00 That's really just the point from where infected and it's inside but has not
07:06 complete particles yet. Right. So can see these are all in stages
07:11 you know if you making viral stuff then putting it together. Right.
07:15 kind of in here it kind of period. We haven't made the particles
07:21 but we're putting them together. Um The so when I was going
07:28 point out kind of in the context chapter eight I guess it was so
07:34 duck shin remember that's that mechanism of gene transfer involving a page.
07:40 That's where this would occur here would generalized trans reduction. Right. So
07:44 the process of producing these fage assembling they would be taking some of this
07:50 D. N. A. That chopped up. right? And it
07:54 package some of these things in the instead of its own genome. That's
07:58 the transaction process occurs. Okay. a consequence of a lighting page
08:04 Okay. And so other viral bacterial viral types can do this
08:10 Okay. Which is the um So Jeannie. Okay so here um
08:19 do begin with the lighting cycle is part of misogyny but it's um it
08:25 two options. Okay? So if if it goes into misogyny, okay
08:31 just integrate into the chromosome. Okay it's uh so this is a phase
08:36 lambda phase that does this. The up here these landing pages are called
08:40 T. T. As in tom . Even like a. T.
08:44 a T. Four T. Six what they're called. And they kind
08:48 have this mode appear land of has this type, right? So
08:52 life life. So jen is when in this mode and we call it
08:57 profane is this act of inserting its into the host chromosome. Okay,
09:03 of course the host is quite happy that's not negatively effective. Right?
09:07 can just continue to grow multiply. of course successive generations are all carrying
09:13 Profane. Right. So at a time then these cells begin to enter
09:18 lighting stage. Okay so remember that needs to happen if this virus wants
09:26 make perpetuate itself. Right? Make itself. So it has to make
09:33 intact viral particles because that's how it other cells. Right? You can't
09:37 stay permanently as this um because it's the way it can affect other cells
09:45 . So you have to get to point eventually. So that means getting
09:48 the lighting cycle and you know, don't go into it so much here
09:51 this course in terms of how, the transition, what's the what's the
09:58 to go this way or that Okay, it's really nutritional.
10:03 so the page in this state can what's going on inside the cell.
10:08 , you can synthesize proteins that kind can there are certain molecules in a
10:14 that kind of can tell you the of the health right? Typically these
10:17 things involved in energy type processes and eight Ep levels, things like that
10:24 it can kind of sense that. um you know, for those that
10:28 be curious, the cue to go way or the other is really based
10:34 the nutritional state. And so if abundant nutrients then of course this cell
10:40 happily growing divide. We already know from chapter four or six, I
10:46 anyway, so it'll give nutritional growth so that's the opportunity then when these
10:54 should exit because now they've got when go into like cycle and these cells
10:59 out come out now they've got lots hosts around them because the cells have
11:04 quite happily to high density and so the time to break out because now
11:10 can be sure of having lots of cells to infect. Okay. And
11:14 when you have deprived cells are okay then they're not going to grow
11:19 well or grow slowly if at And so that's probably not a good
11:24 for the face to pop out of state into the life cycle because we're
11:28 this state now coming out right. guys might not have a lot of
11:35 to in fact. And so that's of that's why really the the the
11:41 nutrient levels and the growth rate of host cells are kind of would drive
11:46 right. Will I have lots of to infect or not if I break
11:50 . So that's kind of why they that, that aspect of the
11:53 Okay. So um ah and so surprisingly, you have of course you
12:01 e coli in your gut, And landing pages in there, infecting
12:05 coli eyes and doing less so ginny it's actually tied if you have a
12:10 right? They've seen where you can a burst of landing page coming out
12:16 infecting cells just when you have a because that food translates going into your
12:21 colon, gets lots of food to , they proliferate and then you see
12:25 you see them coming out of licensing life cycle and then when you're between
12:30 , right? It's less less of . All right. So there is
12:34 just suggestive of this how nutrients can this process? Okay. Um Any
12:41 about any of these parts too? . So as we went to animal
12:48 , let's start with this question Because those are you try to excels
12:55 hosts are more complicated eukaryotic cells. going to be more options if you
13:02 for virus depending on um the type virus. It is Okay but there's
13:10 one thing you can look at that give you a clue as to what
13:15 will do in terms of its life . Okay. And this feature is
13:21 the one that you can use. always foolproof but it's it's it's one
13:27 can use. And so again as go through these ammo virus life
13:33 it's gonna be a little more complicated again the nature of the cell is
13:39 the there's also bacteria viruses we've been about pretty much our D.
13:45 A viruses. Okay. But animal can span much more than that.
13:51 are in a uh single strand of stranded and that can bring another level
13:56 complexity a little bit. So but go through it. Okay so uh
14:03 That count down from 10. Alright. 32 one. Yeah.
14:20 . So it is going to be genome. Okay so um generally whether
14:29 not it has an envelope that's more how it exits the cell. So
14:35 may happen. It may not um in terms of predicting predicting, okay
14:41 have a virus I have a DNA where it might what do I do
14:45 that cell? That's kind of the key. Okay. And so generally
14:51 viruses and so now we're just talking animal viruses. So DNA viruses typically
14:57 go to the nucleus. Arnie viruses . Do their replication in the process
15:04 the nucleus. Okay. So it's about is it going to nucleus or
15:08 ? Generally the type of genome it will tell you that there's a reason
15:12 that. Okay so um so I'm about so we'll start with animals so
15:19 viruses have variations and how they enter . Okay, attachments. You
15:25 The principle is the same depending on the viral type is. Right.
15:29 they have the proteins on the surface the host that they recognize and combined
15:33 and then start the process. But entry can be can vary.
15:38 . So what we call the encoding is simply just how does it get
15:43 genome free and into the cytoplasm. . That's basically what encoding is.
15:51 . And so there's really three different to do it. Okay. And
15:56 it uses processes that already naturally occur selves anyway. Okay. And one
16:04 these is a couple of these are a bicycle. Right so and uh
16:11 may be familiar with um how cholesterol ourselves. So cholesterol binds to specific
16:19 . Okay. And then they'll the initiates a vehicle to form around
16:24 So very much like what this is . So the endo zone is the
16:28 local structure that forms around the Okay, so endo zones form again
16:35 lives of the cell in the form around various things, various chemicals and
16:40 that come into itself. So viruses using that for its entry. Okay
16:45 not all viruses do it this way this is this is uncoated within those
16:49 . Right testicle. So you see the whole virus is actually coming
16:53 Okay. Unlike a bacteria stage. so uh so then this confused with
17:01 with the viral envelope or license um would call a license zone.
17:05 that's one of those digestive organelles. , So confused with that. And
17:09 that will digest the material around the and uncoated uncoated, reducing it into
17:17 cytoplasm. Okay, so this happens be an RNA virus. Okay so
17:24 viral and virus types have this Okay, this is just kind of
17:27 up close of that actual electron micrografx that. So you see the virus
17:33 to these spikes initiating the end zone then it will continue to process and
17:40 unquote the genome. Okay um and it can be what's called receptor
17:48 So that means there's specific receptors here by the virus? Okay, so
17:55 attachment is what initiates the vessel Okay. And so those that go
18:02 the nuclear membrane. Okay, so D N. A viruses right?
18:07 DNA viruses go to the member Not all but most do. And
18:14 again they're doing it by this same own process right, Former best all
18:18 it go to nucleus and it's here the encoding occurs. Okay, so
18:25 then finally there's what's called membrane Okay, so the system would be
18:32 an enveloped virus here. It binds again to specific receptors and then it
18:39 of males the envelope with the cell of the cell. And then that
18:45 the encoding process to occur. eventually the genome gets released. So
18:53 so kind of three different mechanisms. you can see the electron micrografx viral
18:58 fusing the specific receptors. And here see the here back here is the
19:05 of the envelope proteins. And so rest of it's gone infused with the
19:10 and eventually encoding it. Okay, you have endo zone formation. You
19:16 membrane fusion. Okay. Um and the information can either be at the
19:25 membrane or go to the nucleus depending the virus type. Okay, so
19:30 all three are just ways to how gonna get this genome released and able
19:35 to then start the process of replication to copy it and we have to
19:39 , translate. Okay, so um why is it I've been saying a
19:45 of times already, why would the virus need to go to nucleus?
19:50 what's special about that for a DNA , anybody? What the what will
19:58 virus any virus have to do when inside himself? It will have to
20:05 me some, throw something at Nothing but anything but silence. So
20:09 something at me replicate replicate. What correct? What does it need to
20:16 that? What do you say? N A po the memories?
20:27 So what do you find it in host in the eukaryotic cell?
20:35 So if you recall um maybe recall cycle, eukaryotic cells go about dividing
20:44 . So you have to remember it . You have s one,
20:49 The s phase that the chromosomes get ? Right. So what do you
20:55 the primaries? Right. That's so in the s phase of the cell
21:00 when that's occurring. Okay, so of memories around. Right. And
21:06 DNA viruses that need that that's their going to get it if they go
21:11 the nucleus. Okay, so that's need. Now there's gonna be exceptions
21:16 all these things. So some DNA do have their own right, but
21:24 do not and they have that requirement still going to the nucleus for that
21:28 . Okay, so um now other . So as we go through.
21:36 I'm kind of getting kind of the overview here of of each step and
21:41 of some variations. And so we at specific cycles here in a
21:44 But um so obviously one of the they don't have, they may or
21:49 not have a memory. They may may not have uh an RNA
21:54 but they won't have um they won't rivals OEMs generally. Okay, so
22:02 going to have to have the host that and so generally have to do
22:04 things at the end. No plastic . Right? That's where occurs.
22:08 you carry out so they use that that. They made it to use
22:12 golgi. So the gold is typically proteins that go to the surface.
22:17 kind of are made in the gold they go through vesicles that way.
22:21 the virus will use these these various that the host cell itself uses in
22:26 synthesis. So it'll exploit the same . Okay, so with envelope
22:32 um they'll get that envelope. So a viral caps it here.
22:37 And as it exits that will wrap it as it's called what they called
22:43 buds kind of pinches off. Now envelopes around it. But you see
22:49 there are these little red knobby things viral proteins that have been made right
22:56 the cell. And then they go the surface and that's where they
22:59 So when the virus exits, it that membrane and then the proteins are
23:06 . Okay, So now it's ready go. Okay. And so the
23:13 and so it can And so this here, viral assembly and exit.
23:19 can be an animal viruses. It occur at different rates. It can
23:25 slow. Okay. So maybe just few at a time. Okay.
23:30 it can be totally ramped up high . And so that where they're at
23:37 that spectrum, low very high production correlates to a bigger effect on the
23:45 cell. So in other words, of viral production that takes a toll
23:48 the host because it's being resources being away from it. So that host
23:53 will likely die as a result, may be so much production of the
23:58 just license to sell all together. . So, but if it's a
24:02 rate, right, the host cell it's it's it's impacted of course.
24:08 , by that. But it can limp along, it can still divide
24:14 be viable, functional. Okay, that's that's that happens as well.
24:19 , So the cells are not super but they're still dividing but then they're
24:25 off age, I'm sorry, virus a low rate. Okay. So
24:29 that can happen to. Okay, you may see this term called it's
24:34 shedding some cells can be uh described they're shedding virus and that's kind of
24:43 that means. They're kind of going a slow rate and these viruses are
24:47 of burning off and they say they're virus is okay but the wholesale is
24:53 remaining semi healthy and viable. while this is happening. So these
24:59 boxes are kind of just summarize DNA RNA viruses their features. So again
25:06 both boxes there's going to be But for the most part you can
25:11 most DNA viruses with these features but know that there are some variations
25:18 Okay, so again, DNA viruses go to the nucleus. Um the
25:24 so they will do. So the will have functions inside the nucleus and
25:30 outside the nucleus. Because that's what periodic cells do. Right. So
25:36 have replication of DNA in the nucleus then they do translation of proteins outside
25:43 . So viruses that D. A viruses that infect and do the
25:48 thing. So they have to play the same rules. And so they
25:51 replicate genomes in the nucleus. Then will come out into the cytoplasm outside
25:59 nucleus. They'll be translated into proteins they'll come back into view. So
26:02 have stuff going both ways. But ultimately typically viral assembly with DNA
26:09 occurs in the nucleus. Right? you're gonna have DNA in the nucleus
26:14 you're gonna have transcripts going outside and proteins coming in then you're gonna have
26:17 . So there's a kind of a of stuff going on with DNA
26:21 So with RNA viruses it kind of just do everything outside the nucleus.
26:27 . They really have to go into nucleus. And so for that
26:31 you know, they can do all functions out there and use use the
26:36 the past in particular um to do synthesis um these goals you need to
26:42 so they don't need to go into nucleus. And having said that there
26:46 variations of that as well. You to know all these variations but just
26:52 aware that not everything always follows both these rules. Okay. Through virus
26:57 example, it's a RNA virus but it does go to nucleus for part
27:03 its functions. Not not the copyist because these are in a but it
27:08 do some of the assembly process for reason. That's just how it
27:12 So yeah, there will be some will be um that won't follow all
27:17 rules here. Okay, but for you can put them in these one
27:21 these two categories. Okay, so we look at the question, that's
27:26 of an overview of the process that's on in animal viruses in terms of
27:29 life cycle. And so we'll get a little more of the specifics of
27:34 of these types. Okay, um this point, any questions so
27:39 Animal viruses? Okay. Okay. let's look at this question.
27:47 so so are the viruses we're gonna a little bit of a problem
27:53 Right. And let's look at this . So in reference to RNA
28:00 depending on the particular RNA virus Right, Because we have different
28:04 its genome can be used as a for. So if RNA virus and
28:10 got this RNA genome, so what be they can serve different purposes.
28:17 , so let's see if we can out what are those purposes.
28:47 Now 6-3. I mean Mariners, . Alright, any stragglers? My
28:58 1 2nd. Okay, okay, we go. And yes, if
29:09 answered uh d you are correct. , so it's all the above.
29:18 so this this is a um minus virus. This would be a plus
29:35 virus. Okay. And DNA synthesis be the retrovirus. Okay, so
29:46 so depending on their viral type, can be attempted for any one of
29:51 things. Okay, so we'll talk the remember ways back we talked about
29:58 week maybe about the plus minus the antisense thing. So this is where
30:03 kind of comes helpful now, if understand that. Okay, and so
30:08 go through this again. Okay, Alright, so let's look at biology
30:15 function. So we just mentioned. , General DNA virus template for
30:20 Certainly template for DNA synthesis. This is obviously using um RNA polymerase
30:28 you typically from the host DNA primaries not always. And then uh typically
30:42 translation template for the synthesis and DNA . Now these two Okay, you
30:53 RNA polymerase. Okay, there's two they use what's called. This is
31:00 the next slide I think RNA dependent N. A limerick. Okay.
31:14 what that can spell primaries. That that so we we just for
31:23 So we have RNA polymerase. We what's called an D. N.
31:28 dependent RNA polymerase is our only geared copying DNA. Right, Because that's
31:34 first step in transcription. We copy and the RNA and we use it
31:39 RNA polymerase. One that's DNA Okay, so in contrast these
31:47 these RNA viruses here and here. , um they use RNA polymerase that
31:54 are in a what they call it dependent RNA polymerase. So you Kerasiotes
31:59 have don't have this kind primaries because have no need for we don't copy
32:06 RNA into RNA. Right? If need to make more RNA we just
32:10 more. Okay, so we don't that kind of enzyme. So this
32:14 a viral that's a viral enzo so that's something we'll see that's unique
32:25 these two groups. Okay, because they're copying the RNA and RNA.
32:31 so you don't have that. So that's going to be a strictly viral
32:36 okay, that's what enables them to this. And down here this thing
32:42 also a viral and design but it's first and script dates rip taste.
32:55 what retroviruses have. And then they an RNA genome. Oops that copies
33:02 a that copies are in a into . N. A. Okay.
33:09 would it need to copy RNA into ? It's an RNA virus.
33:17 So actually what it does is goes DNA RNA this is it's full of
33:23 . This is um counter to most else in the natural world because we
33:31 and most other living things go DNA protein. Right. This guy goes
33:35 DNA RNA protein. So why would need to have this intermediate bodyguard
33:49 Yes. Yeah. The retrovirus you ? Uh Well it uses for this
34:11 . Peter DNA RNA. It uses our memories. Okay. So
34:20 so what it does it actually goes D. N. A. For
34:25 specific reason. It has to do life cycle. So you're familiar with
34:33 . HIV is a retrovirus. So is RNA virus? We're in a
34:41 cell and the army and the retrovirus a D. N. A copy
34:45 itself. What would that enable that virus to do that other RNA
34:50 Can't do think of the host. . Part of the why And that
35:06 be why? Because of the viral because it can form DNA itself.
35:18 . That's right. So so are retrovirus is a type of virus that
35:23 life cycle is two typically part of is to integrate into the host
35:29 So if it's going to do it's gonna have to go from RNA
35:33 DNA to integrate. You can't you integrate RNA into A D.
35:36 A. Okay. Um and that's retrovirus does. And so it it
35:43 integrate into the host chromosome because it form this intermediate. Right? And
35:49 that do that. So, I'm you probably know that HIV is a
35:55 where you can be infected with HIV not know anything um for a long
36:01 long time because it's sitting in the just doing nothing. Okay. And
36:06 all of a sudden kind of sort speak comes to life, you
36:10 Um by being too slowly replicate. ? So viruses that do this um
36:17 is what we call um Pro viruses talk about this in a little bit
36:22 but pro viruses are analogous to to lambda lice a gyn type that does
36:26 integration as well. Right. So but again, any any kind of
36:32 type that's gonna that's part of the cycle is to integrate into the host
36:37 . It's got to be D. . A. So if it's not
36:39 virus it better have a way to into a D. N.
36:41 Form and retrovirus can do that. The but again, we'll talk about
36:49 in a second, but it's kind that's kind of why that is
36:53 Okay, another example is a the virus is a D. N.
36:57 virus that does this it integrates uh you have a breakdown a fever blister
37:03 a herpes virus that that's integrated into selves that under stress it typically causes
37:10 to begin to replicate. And that's you kind of see it manifests itself
37:14 the blisters. Okay. As it's out. So another example.
37:19 it's one that just hides themselves and of a sudden can emerge at certain
37:24 . Okay, is there any questions that? Alright, so um so
37:30 , with animal viruses there can be lot of different um different things going
37:35 compared to bacterial viruses. So um the viruses we talked about this
37:42 template for DNA synthesis and transcription like . That's what our D.
37:46 A. Does. Um So we just we distinguish between non retroviral and
37:55 . Right, so when you see retroviral RNA virus, you go,
38:01 , we're not talking about retroviruses All right, so we're talking about
38:05 of these types that has this this RNA dependent memories. Okay,
38:12 there's two types, remember. It can be a um it can
38:16 a template for um translation or for . Okay um Mr viruses have that
38:25 we mentioned and for the purpose of to the host. Okay so um
38:32 let's look first at these non retroviral . Okay, well I'm sorry.
38:39 the gun. So here's an example a DNA virus. Okay, so
38:44 typical so this is one that has typical process of going to the nucleus
38:49 coats. Although I just saw from diagram, it's not very good at
38:54 showing that. Okay, so you the viral genome here. So what
39:00 have happened is in this drawing is virus actually come to here and unquote
39:09 that's how the genome ends up in . Okay, so the point is
39:14 um the basically use is hosting a race poppies, genome um then of
39:22 there's host machinery to transcribe into Okay then they're going to have
39:28 you see how materials coming into the , some stuff's going out. So
39:33 have transcripts being translated out here in cytoplasm and then coming back into assemble
39:39 viral particles and then finally exit from cell. Okay, so um so
39:45 viruses that go to nucleus, that's of what they do. Okay,
39:49 go to nucleus copies of genomes, outside of the opiates with transcripts,
39:54 viral proteins, bring it back in and then let's exit all together.
39:59 , um and so here we have by step, process. Right.
40:07 so I mean it's what yourselves do , without if they weren't affected by
40:12 virus, you know, you're replication any cursing nucleus and protein synthesis outside
40:18 they're just following that that pattern. , um now, so let's look
40:27 this question. Right. So it's as complicated as you think.
40:32 uh let's uh look at the Okay, so here we have just
40:39 very basic a hypothetical minus Okay, strand minus minus sense. If you
40:48 . Anti sense minus s single stranded . Uh only 10 Robert and Katie's
40:55 . Right. If you had to , you didn't have to guess which
40:59 below is most likely its genome. , so, you have to remember
41:05 is the minus? You know, gonna look like Okay, how can
41:10 identify that? But you do have hint. Okay. Yeah.
41:58 Count Down From eight. Alright, see. I um now the one
42:17 should eliminate. Right off the bat we're talking about a a virus
42:24 Right. Um Is this that's N. A. Okay. It's
42:32 gonna have RNA only has your cells your cells in places by means.
42:36 you're not gonna see any time means a sequence of an RNA virus.
42:40 right. So you can eliminate that . Okay, so then of course
42:44 between a M B E C. are both are in a Okay,
42:50 , the hint was start coding. right. So where do you see
42:52 start code on You see one Okay, so that's telling you that
43:02 is one that can be a template translation. Right? Remember the template
43:09 translation is the is the plus Okay so that's the translation template.
43:20 um so that would be a plus strand RNA virus. Okay. If
43:24 were the genome The -1 would be . Okay. The anti sense because
43:30 really no identifiable start code on Um and so it would be a
43:37 to make an M. R. , so now you see in the
43:44 strand, right? This is a strand that that contains the stark odin
43:49 the other cardinals and we can make proteins. Okay so um so that's
43:58 plus. Right? So as you we look at these RNA virus life
44:05 , that's what you kind of gotta because you're gonna see a process of
44:11 two things you're gonna go why is doing it that way? Okay so
44:16 let's look at any questions about So let's look at um the
44:25 So here's A Plus Arnie Bar. what you gotta do you think
44:30 Okay, here's what's infecting. Okay we had we already did the encoding
44:38 but picture this is what came right, A virus with a plus
44:42 genome, what ultimately has to happen the end, we have to assemble
44:47 particles like that that will exit the . Right, These are all plus
44:54 . Alright. Plus plus because that's affecting is a plus RNA virus.
45:00 so that's what we have to make only to make it simple only showing
45:04 But it could be a lot more that. Okay but that's that's what
45:08 virus is. Is that? So making more of these? Okay.
45:15 in order to to mass produce you lots of stuff. You need the
45:22 that make up this capsule. You copies of genomes to put in each
45:28 these capsules you're making right? Um you need lots of material. Okay
45:36 because you might think, okay this a plus RNA virus. It's got
45:41 plus genome. I can translate that . Of course you could but it's
45:48 mass production. Okay because you're gonna more than one plus you know number
45:54 you already know you have to make of this. Right? You need
45:58 make copies of that because you have of them in your viral progeny.
46:04 . And yes you can translate that genome in the proteins but why not
46:08 copies of it and make lots of much more quickly. Okay so that's
46:14 we take this R. R. . R. P for short are
46:17 on the primary. So we're gonna lots of copies of minus strands.
46:21 gonna think well that doesn't make Why is it making minus copies?
46:25 these are not because we're talking about RNA virus. These are the basic
46:31 code book how a nucleic acid I'm not making this up. It's
46:36 meant to torture you because we're talking a virus. It's how nucleic acids
46:40 . Okay. It can be DNA RNA DNA RNA RNA DNA DNA doesn't
46:46 . You always have the relationship of to minus. Right. And so
46:53 we're gonna make a lot of copies this genome we have to go this
46:57 because that's just the way it Okay so we make lots of minus
47:03 And then from that we make a of plus copies. Okay so that
47:08 fulfilled the mass production part of Okay so now we're set up we've
47:14 lots of genomes. Alright and then got lots of templates to make protein
47:20 the protein. Right? So then can make lots of stuff assemble and
47:24 out. Okay so this again this 2 -2 plus. Following the rules
47:33 DNA of nucleic acids. Okay and you make it's complimentary, it's just
47:39 complementary base pairing thing, that's all is. Okay we have a
47:45 C. G. And that happens be the plus the minus is uh
47:52 A G. C. And that's just example to say that's the
47:58 Okay that's the relationship. Just complementary pairing. Yes. Obviously it would
48:02 easier if you could take a plus make a plus. Absolutely but it
48:07 work that way. Okay so um when we look at the other
48:13 the minus RNA virus. Right. logic. Right? This is what's
48:18 in. Right? We have to lots of these lots of protein and
48:23 minus genomes. And so again, one virus is infecting that's not gonna
48:30 enough. Right. Plus we have make we have to copy this anyway
48:35 the minus can't be translated into We have only the plus strand is
48:39 to do that. So copy make lots of plus strands and then
48:45 that translate the proteins and then make of the pluses and the minuses.
48:52 our genomes. Right? So now can package those in. All
48:57 Yeah. So in this scenario going plus minus again, just following the
49:03 DNA nucleic acid rules let's call Okay, so those are your two
49:08 viral types? Single stranded types now double stranded RNA virus, you
49:13 it can similar thing. Right? has the minus and plus strands to
49:18 and so forth. Okay, um this is the greatest slide from your
49:26 . But the in fact I think is probably better but you know,
49:32 be the judge the just the same we just talked about. Right?
49:37 we have this is the scenario the RNA virus going this way minus one
49:48 stranded. So you don't you don't to memorize this slide but it's more
49:56 do you understand the process of top bottom? Like what's going on?
50:03 questions about that? Okay. All . Um so let's look at the
50:13 . Okay, so this is gonna its own thing, unique thing.
50:19 , so here, as mentioned, going again that's going to be a
50:25 enzyme. Okay, we're gonna copy D. N. A. So
50:28 , there, you see the same rules, Right? Plus until
50:34 Even if we were making our RNA DNA, it's we're following the same
50:38 . Plus two minus. So, so a single strand of D.
50:42 . A. It's not gonna be , right? Because if it's going
50:45 integrate into the host chromosome, gonna to write. So but it can
50:51 host enzyme to make the complementary Right? So now we have double
50:56 DNA and this can integrate uh they use the host or embrace if it
51:02 to go into transcription mode and then proteins. Okay, so these guys
51:09 um does does not the I'm just to abbreviate the are are independent on
51:27 preliminary Is that one we saw in non retrovirus types, right? That
51:32 there are retrovirus does not have Okay. Because it's not it's not
51:37 that. Okay. It has this that's it copies its genome in the
51:43 and it relies on host enzymes for process and that process. Okay,
51:51 no it's a different life cycle than these non retroviral RNA types we just
51:58 about. Okay, so, so then, of course the same
52:03 assembling the Syrians package, etcetera. , so, um here is life
52:11 depicted here and so we have um transcript based of course is a viral
52:19 and so we're making a copy and using host primaries to make the double
52:26 DNA and then um then integrate into nucleus. And so this process of
52:33 is a pro virus. So remember use profane age for the material virus
52:38 that does this is the pro virus animal viruses. We use that term
52:42 animal viruses. And so um the so with HIV which is an example
52:49 a retrovirus um it can initially just in the chromosome. So HIV infects
52:56 very specific cell type in the It's a type of immune system cell
53:01 it can produce what's called a persistent which means it kind of just sits
53:05 and persists hence the term and it it can assume different roles. So
53:13 typically it just is in the chromosome that's all that's happening. None of
53:18 is going on just kind of sitting . Okay. And in that scenario
53:24 person would be would not test positive HIV because it's just it's not really
53:30 only being a test positive when viral begins to occur and builds up to
53:36 level that you can detect it. if that's not going on and you're
53:40 gonna be able to detect anything. so it can be in a state
53:44 quite some time, months years. . But of course the cells are
53:50 during that period and each of those successive cells are containing that pro
53:56 Okay. But then at some point may begin to ramp up, begin
54:00 ramp up begin production of viruses and do it this way. So transcribe
54:06 M. R. N. Translating the proteins right, assemble
54:10 It has an envelope so it'll exit will have viral proteins on the surface
54:16 now it's envelope and on it goes but it can go at a lower
54:19 low rate of production a few viral Purcell. Okay. Uh And then
54:26 continue that for quite some time but you know it builds up and then
54:31 begin to reach a threshold where you it and you're HIV positive. And
54:39 um and so of course obviously that's the trigger to start you know treatment
54:49 drugs to counteract the viral infection. And so the budding process is what
54:55 what produces the envelope as it Um So there are targets for these
55:02 drugs. We'll target different parts of process. So particularly it was a
55:09 called a Z. T. Which still used that was one of the
55:13 ones developed and still used. It with the action of of the verse
55:18 base. Um And there's hank treatment it's like a combinations like nine or
55:26 different antiviral drugs together. I think still the way it's done. But
55:32 is uh is fairly effective. it's not like it was 40 years
55:39 . Okay. Um 30 or 40 ago in the eighties when there was
55:46 not much treatment and high mortality So um nowadays it is a very
55:53 disease. You can live a basically life. Okay. Um the but
55:59 course uh this leads us into other science areas of politics and whatnot because
56:07 are parts of the world where this epidemic and people are dying from it
56:11 they don't have access to the So like I said, that's a
56:15 lot of discussion. Um but any about retrovirus. Okay, so um
56:25 look at I think we have next . Uh this is kind of a
56:31 of bacteria fades. Ammo virus Um you know one of the main
56:38 really is that the material fades the everything but the genome enters to sell
56:44 else is I'm sorry the genome only the rest of its phase out for
56:47 viruses. It can be the whole comes in. Um So like so
56:52 and with the page we saw with is analogous to the pro virus formation
57:00 animal viruses. Um So you just more complication because viruses are affecting
57:07 cells. Right? So nucleus can a part of the process but certainly
57:12 a thing for page. So you , kind of recognizing these basic differences
57:18 . So. Alright, so these next two things Lions and vai
57:26 Okay, they are not bold letters . Okay. They're not they're not
57:34 viruses by the virus definition. So don't even call the virus.
57:40 , so a prion and a viral are both infectious units. Okay.
57:49 is a protein, one is an molecule and that's the extent of the
57:54 . That's it. There's nothing else it except that that okay, so
58:01 up Ryan's and so uh familiarity is mad cow disease. May have heard
58:07 that. Um I think it was discovered in sheep. I think scrapie
58:13 the sheep version of this. Um is I think the practice of cannibalism
58:24 brains infected with this. That's that's kuru is still happens I guess in
58:29 of the earth. Um But the felt Jacob is what they call the
58:34 form of the disease. Okay, um how would the human get infected
58:40 us eating, eating um uh food from an infected animal. Okay.
58:48 e meat from an infected animal. The uh you know the chances of
58:55 this, you're probably chance of getting by lightning and probably better than catching
59:00 prion disease. Um It's not that certainly in this part of the
59:05 Okay. But what's unusual about it course is that it's a protein that's
59:10 which is really but heard. And um the uh to my knowledge um
59:20 is the only prion type of disease aware of. Uh but in any
59:25 what it is is you have a form of this protein. Right.
59:32 what happens is it's basically a protein misshapen misfolded and then that's what causes
59:39 disease. Things accumulate over time. . It's a very slow progressing
59:44 Okay. Um and I mean there no cure for it, but
59:50 chances there there's some evidence that there a genetic component to it. Um
59:56 um it causes neurological impairment, it neurons in your brain. Um but
60:05 protein itself, you have a normal of protein in your brain cells.
60:10 fact a lot of yourselves, but in your brain cells and that's what's
60:14 a glycoprotein. Okay. And it in the membrane of the neuron?
60:19 . The function of it is really not known. There is some evidence
60:24 it has something to do with copper of all things kind of weird.
60:29 um but it hasn't really still been what the true function is, but
60:34 it is changed and mutated then there a definite consequence to that.
60:41 and so and so what you're seeing in terms of normal and abnormal forms
60:47 a mis folding of the protein. , and so it causes the
60:52 Well it's when you have a what's a prion proteins, that's a misshapen
60:59 . Okay, it binds to a form of protein. Okay,
61:03 how would you get the misshapen form eating contaminated tainted meat from an animal
61:08 has this? Okay, there's some that there's a genetic component to it
61:13 well. So that could be a . But regardless, the binding of
61:17 prion to the normal protein is what this miss shape to occur.
61:23 And so this continues to happen and you get more and more good prion
61:30 bad ones if you will. And then these begin to accumulate
61:34 Slow progressing doesn't happen overnight happens over years, but you begin to accumulate
61:40 neuron for example, will accumulate these proteins and then begin to affect its
61:47 . Okay. And so what happens the whole so here's brain tissue for
61:52 holes. You see our neurons once to reside neurons has basically just
61:59 gone away. And what's left behind a space. Okay, so you
62:04 want brain tissue to have look like cheats. That's not going to be
62:10 well functioning individual. Okay, so and that's what they call these plaques
62:16 . So uh any case of so lots of holes in the tissue
62:21 kind of a spongy this texture, what they call it. That.
62:24 , so um it is surprisingly resistant various chemical agents and temperature and things
62:31 that. So if you happen to meat that tainted with this a you
62:37 wouldn't know it but you really have heat it very well. But but
62:42 , so it's it's a you know it's just an infectious protein and this
62:46 how it multiplies basically by binding a protein and that changes the shape of
62:51 . That's kind of quote, the occurs this way. Okay. It's
62:57 a protein. Okay. Um many about that. Okay, so and
63:05 just shows you a little cartoon of green are the normal prion proteins in
63:11 membrane. Okay. And the red are the ones that are accumulating bad
63:16 and eventually it will take over the uh killing it uh destroying its
63:22 And so uh so the last of types of weird types is this infectious
63:30 viral. Okay, so as far I know, Bayreuth are only a
63:38 problem for plants. Okay. Certain , there's not to my knowledge,
63:45 things have yet to cause any issues humans. Right? So vai roids
63:49 strictly certain plants. I think the well studied 11 that affects a
63:55 Okay. And so what they are course is just RNA. Okay.
64:02 unlike D. N. A. . A. Is not double stranded
64:06 are in a can fold on So it's just just regular complementary base
64:12 . One of these bindings occur and form these kind of structures.
64:16 so you see here um and so structure itself tends to be important for
64:22 function. The other thing about RNA is that some are can be can
64:27 enzyme activity catalytic activity. Okay and uh good example. That's the arm
64:35 Zone puts together the immediate answers to a protein and it's an RNA in
64:39 bible's own that actually does that. so some RNA can have an enzyme
64:44 and this does okay, it's very , 304 nuclear times pretty small.
64:51 And so we use the host RNA to make more copies of itself.
64:56 so what they think these things do disrupt question this disrupt the normal expression
65:05 genes in the plant. Okay so will these things can be combined to
65:12 transcript. So we have A. . R. N. A.
65:14 a plant. Okay, so then of these viral loads may kind of
65:22 . Okay let's call that the thyroid , R. N. A.
65:29 one of these parts of the R. N. A. Now
65:32 ribosomes here. Okay and because we this big fire way bound to the
65:42 , it cannot um translate. It get around it. So it kind
65:47 blocks translation. That's one of the it has. And so by doing
65:52 it disrupts expression of certain of these genes. So that's how it causes
65:58 um how these things are transmitted. , the plant, I don't know
66:03 that's known. Okay. Um but it's it's just it's always as
66:09 That's it. Nothing else to it using host memories and that's pretty much
66:16 . Okay disrupting to the expression. you have an infectious protein and prion
66:20 are in a uh vai right okay let's um look at I write for
66:31 . So which statement? Right. of it may be true but the
66:34 thing has to be true. The thing has to be true if you're
66:39 pick it. Okay so we have um vai roid crayons like a capsule
66:49 . Black nucleic acid fibroids contained DNA RNA brian's heavenly. Arnie prime particles
66:59 increase in numbers or words cannot raise . Do not. Um Prions can
67:10 combined with the host. Can recombine hosts. Okay that's very bad.
67:16 can recombine with the host of the ? With host genome? With the
67:21 genome. That's what I'm supposed to . Ha okay with the oh gino
67:31 better. Okay viral cannot order the are completely true. Okay. Okay
68:24 count down from 10 and yes if answered d you are correct. Okay
68:46 that's uh any questions That's how we're do today folks. We'll wrap this
68:53 on Thursday and then start chapter Okay. Thanks
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