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00:13 Okay, folks are for a I couldn't get an internet connection up

00:18 . Uh Anyway, so I also expecting a four degree temperature change from

00:27 . Um All right. Uh Let's . So uh information information you're aware

00:35 already, but just to remind So we'll get we're back on turning

00:41 in this week. We have a beginning tomorrow through sunday and smart work

00:46 I know that I had forgotten to was maintenance. The publisher was doing

00:51 , which is why the thing was . So it is now I checked

00:56 morning and assignments for this current unit now visible. Um So uh that's

01:05 6, 13 and 14. Um see. So today we're gonna continue

01:11 with viruses get through pretty much all it. There's very little left to

01:16 on Monday, but then we'll start 13 the first part um which we'll

01:22 it kind of flipped fashion. And video for that material's been up for

01:27 week now. So do you take look at that before monday? and

01:34 we'll go through uh the part one kind of more of the background info

01:41 metabolism and so um Kind of the there are important in really understanding the

01:49 of 13 and then 14. So go through it and uh I know

01:57 about chemistry maintenance, happy about but it's not going to be Hardcore

02:03 . So um I'm not gonna expect to know all the 50 plus different

02:09 and things like that. So there's method I got to to to teach

02:13 . So so so it's not so seem so daunting. Okay so but

02:19 mhm. We'll start that on on . So example one is is open

02:27 constant. So if you take a you have questions come by office hours

02:31 schedule of office hours or email, have you if you have questions.

02:36 um let's see. So let's uh with just a bit of a review

02:44 we talked about last time. So lecture was mostly about virus definition

02:51 Okay. And the classifications kind of not ended on that. So remembering

03:01 the definition of a virus. Remember not cells as we define a cell

03:07 . They have this basic structure of protein coat surrounding the genome. Actually

03:14 genome which can be of different types RNA DNA single strand of double stranded

03:20 The shape of the capital of Canada pulled ahead real shape. It can

03:24 a filament, this type of virus can be a naked virus without an

03:28 . It could have an envelope. And so there's gonna be variations beyond

03:34 that basic um uh protein coding genome . You know of course envelope proteins

03:42 be President Glafcos glycoprotein spikes, they them. So remember the number of

03:47 proteins on the periphery here are going be involved in recognition. Right.

03:50 that brings us to the infectivity. . So that's all about viral recognition

03:56 the host which all occurs through molecules the periphery of both virus and host

04:03 . So uh that recognition and brings Um binding entry of the genome eventually

04:12 the beginning of the viral life So um we'll talk about viral life

04:17 today. That's kind of what the two is about. So um and

04:22 and prions. So remember that viral ? No they're not viruses. Maybe

04:28 virus like if you will but they they lack uh they lack of

04:34 For example, you don't have the viral features but they have basically an

04:38 protein or infectious RNA molecule. And that's it. There's no other structures

04:43 with each of those two entities. . And then classification is kind of

04:48 we ended last time. So so you know, you can look at

04:54 number of different futures, you can at all these features over here.

04:58 know, use those as a framework classify a virus. Right. And

05:03 the Baltimore classification has to do with the genome. That's how the group

05:08 then then they're out to get to um form which is the transcript which

05:15 then be translated into proteins. The M. R. And

05:18 And so there's different routes. Of we can you can easily um wrap

05:24 head around group one and two because A D. N. A.

05:27 that's that's how we work, DNA to RNA to protein. So

05:32 for these other groups the RNA group can be a little complicated. Okay

05:39 um it's this plus minus um designation um so number one the plus form

05:53 the coding form of coding information. . The minus strand is also called

06:03 sense strand. Okay. The minus um the anti sense. Right.

06:12 so they can be a template to a plus strand. Right. So

06:24 as can this plus strand be copied a minus strand? Okay. So

06:33 that's why it's as we're gonna go this again. Okay so two things

06:40 the we do you carry loads. and pro carry outs us non viral

06:49 . Okay. Um we don't have need to copy our RNA molecules into

06:57 RNA molecules. We don't do There's no need for us to do

07:01 . Okay we do take our N. A. And copied into

07:06 . All right. That's what's happening us and it's what's happening up here

07:10 these two groups. Okay. Because have a DNA genome. Right so

07:15 you go through the process of expressing and making proteins we're gonna go um

07:21 the DNA into a an RNA into plus RNA. Remember the plus RNA

07:27 always going to be in the The plus RNA is what contains the

07:31 information okay to be translated into a . The uh so this business over

07:38 then right of going from copying and and all we're doing is not because

07:44 talking about viruses is just simply the laws of nucleic acid replication. That's

07:51 we're falling. Right. We could talking about whatever. Right? That

07:55 a clinic acid. If you're going copy it, it itself is some

07:59 it's either plus or minus strength between copy, it is going to make

08:02 complementary strengths plus or minus. that's all that's going on.

08:07 You take acid base pairing rules. . So, um, so for

08:14 RNA virus, depending on what type is, it may have to go

08:19 a few different routes to get to to a a to a transcript in

08:27 . Um, you see here, , and you're thinking, okay,

08:33 is a plus single strand RNA group can serve, right? That plus

08:38 can serve their genome can serve as a Robin can plop on there and

08:44 purchases. Okay, So why in hell does it have to do this

08:51 this to make more clustering is why it do that? Because it's about

08:58 amount of stuff you need. so I always harp on.

09:02 here's a virus affecting the cell. the ultimate endgame. That's gonna happen

09:07 something. Lots of little viruses. ? Each of those little viruses is

09:13 up of protein capture needs to make that's protein gotta make it gonna stuff

09:18 genome into each one of those Okay so you need quantities of

09:22 One virus infected with one genome is gonna be enough. Okay you've got

09:28 make copies of those genomes right eventually they're gonna be sitting in capsules that

09:34 gonna be the the babies for the . Okay. So that's and because

09:40 a plus on a virus and you copy a plus into a plus the

09:46 of his whole life to do Okay. Because that would be the

09:51 of saying if my genome is A. Um G. U.

09:59 . Okay. And that's a All right I'm going to copy that

10:04 a plus strand then. What would copy be? It would be

10:09 A. G. You see it work that way because what's the

10:15 See you see A G. That's copy I'm gonna copy that molecule.

10:22 what you're gonna get. You're not get a cluster. It doesn't work

10:25 way. Not even hours worked that . Right. We probably have plus

10:29 . N. A. Stream. we don't well yeah we copy that

10:33 DNA strand. We make them minus and vice versa. Right? So

10:38 it's not because we're talking about viruses it's universal. Right? When you

10:42 about new pay gas. Okay. um so this guy in this group

10:49 has to do it this way. they all have to do it this

10:52 . But it's starting with a plus but because ultimately in its viral life

10:59 it's gonna make a lot of our . You gotta have lots of copies

11:03 that plus genome. Okay and because can't directly copied into more pluses that

11:09 course that would be easy. It be great to do with that.

11:12 it doesn't work out. You have go through to get to this

11:16 right? That plus trend. You go through here. Okay. So

11:23 may sound crazy but that's the way works for minus single stranded RNA virus

11:30 below it. Um That minus RNA be copied into a bunch of

11:36 Okay that they can be translated into but it's too um and of course

11:44 his classification scheme we're just focused on to to the M. R.

11:49 . A. Right? But for guy okay it will have to then

11:55 on and copy that with that. . Remember this RNA dependent RNA

12:00 Right so we don't have those. have a DNA dependent RNA polymerase.

12:05 what happens when transcribe our D. . A. So but they're copying

12:09 molecules which we don't do. Okay so they have that viral enzyme to

12:14 that. And so even this guy has to eventually copy these plus strands

12:18 make the minus because why? Because its genome it's it has to make

12:25 bunch of copies of that stuff into eventual viral progeny being made in the

12:33 . Okay so um so we're gonna rehash this again in a few slides

12:39 the road. But that's that's the because this confuses people. I wouldn't

12:44 harping on this unless I knew would people because it does I've seen this

12:48 and time again. So um uh that in the last group here

12:57 right So they have a Plus, Gino but they are different from these

13:05 groups because they are going and to that into DNA reverse transcriptase. And

13:12 that's because their environment type that integrates of their life cycle is integrating to

13:18 host chromosome. And so to do you need to have a D.

13:22 . A. Form to integrate. and then of course when it does

13:27 to going to replicate it will have copy that into uh RNA transport.

13:37 so like I said we'll rehash this in a little bit. But any

13:44 here. Yeah. Uh the S. Stands for double straight double

13:54 and single stranded. Right? So you see a single strand is assuming

13:59 has to specify a. Yes. . Yes. Yes Yes. If

14:05 a single strand absolutely have specified plus that's right. So why does it

14:12 if the end result is the Why does what matter what does it

14:18 which group it is? You know the end result is always no that's

14:24 the nature of that virus, I it can make a difference if it's

14:29 depending on viral type and the kind disease that causes or what have

14:34 I mean it's it's it just matters the purpose of what? Well it

14:40 isn't all the same because the minus trends are in a group. Well

14:44 they all go to making that somehow go to making a transcript,

14:49 The M. R. And Plus. So how they get there

14:52 differ. But yeah they are they're going to get there. They have

14:55 right to make their viral proteins for . But then what they may differ

15:01 UK they gotta make copies get their in there as well. So the

15:06 single friend Arnie group's going to vary the plus because they have to do

15:09 step to get copies of their Okay. So yeah I mean so

15:15 I mean so many things look similar but but this extra step here it

15:20 nearly for that guy to make copies pacino so you do see some differences

15:25 yeah but the viruses themselves and each can be very different. Okay in

15:30 of the self same effect and the that cause and severity of those diseases

15:37 versus a Ebola, both RNA So they're definitely our differences. But

15:44 when you get down to the the of this process, it can look

15:48 . Okay they other questions. Okay um okay so again don't memorize this

15:59 . I just put this in there a couple of things. One is

16:04 the having just gone through our new and make me think about it is

16:13 so many in that in both those that we are familiar with in terms

16:18 causing human disease. So um the of course is in the plus RNA

16:25 um rabies virus West Nile is endemic this part of the country. Um

16:31 always have cases of that in Houston year. Um poliovirus not so much

16:38 anymore but the flu flu I think already mentioned. So a number of

16:45 and mumps as well. A number these are in the RNA virus

16:49 Okay so the last group you haven't was this this group here? This

16:58 . 7th para retro viruses. So of I guess a variation of retroviruses

17:06 want to think of it that What they have of course is the

17:10 genome not RNA. But in order make copies of their DNA genome,

17:18 don't copy their DNA. And the . They copied into RNA and then

17:22 R. N. A. They that back into D. N.

17:24 . Okay it was kind of a bit of a oddball group that way

17:31 they don't copy our D. A. I guess using DNA.

17:34 so they go kind of this Ok. The Hepatitis B virus which

17:42 liver disease um uh it's quite contagious is in this group but this is

17:49 little bit different in terms of their cycle. Okay so um so let's

17:58 at so as we go into um so we've kind of gone through this

18:04 kind of presented as a here is of a basic by a lifecycle applicable

18:10 all viruses. But as mentioned we're to see variations in the process different

18:18 and so this is more than just of a rehash of that. So

18:24 again all begins and ends with the recognition uh between virus and host

18:31 He's gonna be through various proteins on surfaces of both types um viruses can

18:39 you know various types of receptors on on a host cell um many different

18:46 of molecules making interact with of course there's a specificity to it. Okay

18:52 um interested genome. So of course a lot of variation here. General

18:58 with bacterial viruses or fage. same thing. Um only the only

19:04 genome enters everything else stays outside but animal viruses you see where generally the

19:11 can come in uh then it gets inside the cell in different ways so

19:18 see variations there the synthesis and So once the genome is free to

19:26 copied. Uh huh. The then course this the virus is taking over

19:32 cell replication factory inside the cell. we're gonna um not just make copies

19:38 genome but then make transcribe translate produce our proteins and begin to assemble and

19:45 eventually released from the host cell. so throughout the whole process um again

19:54 the spectrum of variations here. So rate at which viruses are produced.

20:00 you can nearly have cell viral types will take over to sell and produce

20:05 that much virus. You see they're you only see three exiting right?

20:10 you might just see a handful of and exit. So In some cases

20:15 can see bacteria viruses can produce almost faith Purcell. Okay so the the

20:24 of viral reproduction occurring of course it a toll on the host. Right

20:30 the host is being exploited to make these proteins for the virus. Obviously

20:36 energy that the cell could do something with besides wasting it on this.

20:40 so it agreed to which viruses are made inside the cell. Of course

20:47 that impacts how much this whole cell can survive. Okay. Because it

20:54 the host cell uh undergoing this viral can can survive while the virus is

21:02 it's safe if the power production as . Okay well we'll see that.

21:07 see examples of that. Um But times other types where that's not the

21:13 the virus gets in there and just hundreds of page particles. And that

21:18 totally overwhelms this wholesale and you can't with it and it dies.

21:24 um, and even for viral types do the kind of low level

21:29 keeping the wholesale live. Okay. that that will even ramp up in

21:35 and ultimately kill the cell. It , you know, the time implemented

21:40 infects its host cell to when the cell eventually dies can get married can

21:44 minutes, two years until it Okay. So all depends on the

21:50 type. Okay, so, no. Okay, let's look at

21:57 question here. So, the first we're gonna do, I need there

22:03 go. Okay, I need to this first. So let me do

22:09 . Okay, wait a minute. isn't that information showing up? There

22:14 go. Sorry. Okay. now you can answer. Okay.

22:19 while you are looking at it so we're gonna Look at bacteria viruses

22:25 . Then animal viruses, um, viruses their cycles little little not as

22:36 typically. And so mainly because of host cell, pro cryonics cells aren't

22:41 complex as you can see themselves. animal viruses can be more complicated because

22:46 more stuff in eukaryotic cells, they go to different organelles and things.

22:52 it's a can be a little more . So we always start with bacterial

22:56 virus first. And um the uh let you answer the question and then

23:07 go through that. A couple of of different materials virus types will look

23:12 . In fact Actually three types. types. Mm hmm. I was

23:32 a part of the excitement. How d. Yeah it's just kind of

23:42 . Okay. Yeah it's just I do it determined just you're probably right

23:48 just trying to stuff as much in as I could. General knowledge type

24:12 . Okay. So whenever you do the term fage or bacterial fage that

24:28 obviously bacteriophage refers to bacterial virus. you just see fage. It's always

24:33 with bacterial viruses. Okay. Okay so winding down 321 boop.

24:46 so um F. F. Is . So what are the two that

24:53 not part of the cycle? And D D. And E.

25:02 think that is correct. Okay. D. Athletic stage are virulent virulent

25:11 . Right. So they will learn their mode of operation is in fact

25:17 viruses kill cell and takes it infect cells. Um D. E.

25:26 . That's that statement is true. think most every bacterial virus type is

25:32 only the genome enters other stuff Okay. A lot of it has

25:36 do with the fact that bacteria have cell wall. And so um it's

25:42 amenable really to bring the whole thing . Some journalists the genome enters.

25:47 so um to material life cycles. your face life cycles brother. Of

25:54 . Like any virus. It's it's of course have the recognition um attachment

26:00 the hotel the t even phages are type of look at first. There

26:07 little viruses virulent page that like I they're mode is too in fact make

26:15 and kill the cell and then go to infect other cells. Um They

26:19 produce lots of virus very quickly rather . Okay uh The estrogenic cycle will

26:25 at next is lambda fage which is to E. Coli and it will

26:35 a you might say a dormant state part of its cycle. So it

26:39 integrate into the hell of chromosome called what's called a profile page? It's

26:46 does so at a specific site in E coli genome and in doing so

26:52 that pro fate state the host cell not really negatively affected. It can

26:57 just basically grows and replicates as it would. Okay. But then that's

27:04 it's only final. There's a point that will end and and it actually

27:09 into what's called the lighting cycle. the estrogenic fage like lambda can go

27:15 and forth. Okay between the latex and a less hygienic cycle. Um

27:22 it's all about, you know the of the host cell determines which way

27:27 goes. Okay. So I've kind combined both. Uh So we're gonna

27:34 at atlantic cycle first which um I just this part here. Okay so

27:45 once the genome interest itself uh viral will begin to be synthesized and for

27:51 all viral cycles generally kind of coordinate where you have like what are called

27:56 viral genes in late because different parts the viral life cycle occur at different

28:03 . So if you're trying to get the sell wholesale and then begin the

28:08 , that requires some different proteins that need later in the cycle,

28:12 when you're assembling things and so So um one of the first things

28:17 for a little page is to really the host chromosome. Okay. And

28:24 it will then basically use those nucleotides um for its own purposes to uh

28:30 copying its own genome and then quickly for our proteins assemble and uh make

28:39 progeny fade inside the cell and again a high rate Upwards of 500 per

28:46 . Okay. And so a and bacteria can grow so fast um you

28:54 have a a one mil culture of coli that's very dense. Okay,

28:59 can add a drop of land a phase to it. And within 30

29:05 the whole thing is cleared up. looks like water almost because the seller

29:08 effect produce lots of our particles per . Then they come out and infect

29:14 cells. That's what actually occurs in exponential fashion where these cells are all

29:19 off. So um very efficient. Now so again like athletic phase.

29:28 all it does is what's in that . Okay, now the less hygienic

29:33 have additional part of that cycle. they can effect and um incorporate themselves

29:43 the genome. So here is uh the purplish part of the chromosome here

29:50 the profane. So it doesn't negatively growth. It keeps multiplying dividing generation

29:58 generation. It's just that each cell subsequent generations and a copy of that

30:05 . Okay. And so the it's it's kind of a ticking time bomb

30:13 you will. Okay, because eventually will have to go into atlantic

30:17 That's the only way the virus can more itself more of itself is to

30:21 into atlantic cycle. So the question that what's the queue to do

30:26 Well, while it's in this state . Okay, profit state. There

30:31 proteins that are being barrel proteins being that can kind of sense the state

30:38 the host cell. Okay. There certain types of signaling molecules and they

30:44 healthy cell while its rapidly growing and that that the the viral proteins can

30:50 . Okay. And it's when when would go into the logic cycle is

30:58 if the host cell is actually under good um nutrient conditions, under good

31:05 conditions has grown very rapidly. Lots generations being produced. Because uh for

31:14 from the perspective of the virus that's time to go into politics cycle and

31:19 lots of page because they will all have a host around. Right?

31:24 cells are really growing very rapidly in episode means the highest cell density of

31:29 cells. That's the opportunity to then out of the lighting cycle. And

31:33 make more faith. Okay. It's the host cells are in them,

31:40 a good growth state, right? the profits will tend to stay in

31:46 profile page form. Okay. Um so because if it did then there

31:53 be a lot of opportunity for these being produced to find a host.

31:57 it's kind of times it with the state of the growth rate of the

32:03 . Really. Okay. But you um in the lab you can kind

32:10 use other means to to trigger You can like elevated temperature uh slightly

32:16 can kind of trigger the process. in nature it often happens that it's

32:21 the nutrition nutritional state that the host and how fast they're growing dictating whether

32:26 stays as a profile page or it into the landing site, enjoy

32:31 But the point is with the profile or with lambda phage both both are

32:36 of its um lifecycle. Okay. process. Um Now any questions about

32:46 . Yeah. So a third bacterial type, it's a little bit

32:52 Okay. It will um you might it's kind of maybe a variation of

32:59 two. Okay. But M. is one So it's a little bit

33:05 then lambda it's it's a filament. type page. Okay. It will

33:12 in fact and then stay inside the . It does not does not for

33:17 . Okay but it can't hang out the cell and direct synthesis of

33:24 Did you see there and the host remains viable? The host cell remains

33:32 while it's producing viruses. Okay. different from obviously different from landing

33:40 Right because the medication effect maybe it producing viral progeny and then killed

33:46 Different from lambda because it's not integrating the genome. Um Lambda will only

33:55 new viruses if it enters the Okay well it's a profile page that's

34:00 happening. Right. It's really nothing happening in terms of the virus But

34:05 13 can infect the cell. And then um exit right. Produced

34:12 viral particles. You see it out . Okay but it does. So

34:17 a low rate. Right? So it's all about taking a toll on

34:21 hotel. Okay So if you only a few at a time but the

34:27 cell can live with that. Okay um uh it's like we're certainly not

34:34 to be growing at the same rate it would if it didn't have that

34:38 but the virus isn't producing a lot viruses either. So it's enough for

34:43 sale to say okay I can keep the body. So when we look

34:48 that kind of a strategy, okay does this benefit? M.

34:55 Why is that a good strategy for ? What is it what is it

35:01 gain that perhaps the others may not ? Yeah I guess it just has

35:08 longevity with its host um meaning that guess it's like it kind of gets

35:16 stay um if it doesn't really Okay. Did you have tell me

35:25 ? What else have a david? . Was it more what uh kind

35:36 you're kind of getting hitting almost at target here? So what does um

35:44 for the example of I gave you the lighting fake and I said okay

35:49 B. E. Coli That light could just blow through and kill everything

35:54 30 or 40 minutes. Okay. any phase that are kind of now

35:59 out there, do they have a to infect? No, but

36:04 13 likely will. Right. Because with m. 13 it's kind of

36:11 of always having a host around. , so it doesn't have the same

36:16 production as these other types but but has lower production but it's pretty much

36:24 of likely always having a host around infect. Okay. So it's kind

36:29 it's it's mode of doing things is way? Okay um you know these

36:36 how these things evolve and how they their particular type of strategy.

36:42 You know the the the light of land of age. I mean those

36:48 are in your gut. I mean if you have a course all kinds

36:51 Brazilians to be cola in your Uh And and they they kind of

36:56 they can they can of course affect and when they when the lighting when

36:59 when the e. Coli that have pro failures and when they begin to

37:06 out and go into the logic cycle really when you have a meal that

37:10 eat and of course I mentioned that gets down there gets broken down in

37:14 gut and equal and they began to those nutrients. Right? And that's

37:19 cue for the light of the land phase of let me get into like

37:23 . Start doing my thing. Okay it's A. But M. 13

37:27 kind of a different different way. . Um All right any questions about

37:37 could you explain the all this is it means is single stranded single strand

37:43 strand. Okay you see they're gonna a plus or minus. So you

37:46 say single stranded plus or single stranded . Wouldn't just be just S

37:52 Okay. Um Alright so here uh a little bit about what the defenses

38:01 that bacteria have against the viral correct? Um This one here is

38:09 of course at all genetic resistance. every um life form that gets infected

38:17 a virus has that as an Okay because that means there's a member

38:22 the population are members of the population the species. That mutation that may

38:28 altered their peripheral proteins that the virus and it changes enough that the virus

38:34 infect it or can effective were infected very weekly. Okay so um so

38:43 a mechanism that all host cell potentially um restriction and the nucleus is so

38:51 bacterial. Um your knowledge that luckily from the continent D. N.

38:57 . And clothing jeans and vectors and kind of stuff. And so restriction

39:02 cleave D. N. A. . But there they are originate and

39:07 found actually in bacterial types. And thousands of these things different types but

39:14 all do as they recognize particular sequences D. N. A.

39:20 And they recognized these palindrome IQ So palindrome is like the same.

39:27 we have a sequence meeting this way in the inverse sequence. So

39:32 A. T. T. G. A. T.

39:35 T. C. On the So they have kind of that

39:38 Right. And so a uh this for Echo R. One. So

39:42 R. One, his E. a restriction enzyme one was one of

39:48 first ones discovered and it will recognize sequence. But make a cut.

39:54 ? Where you see the slashes. . So they create if you recall

39:58 term sticky ends. Alright, so make a cut like that.

40:05 Where the DNA will part of course will make multiple because there are multiple

40:10 like that in the D. A. So of course there's a

40:13 DNA. Then it's chopped up and infection is over for it. Of

40:19 bacterial DNA is protected because the sun can be methylated. Right? And

40:27 means that the restriction enzyme can't really and recognize those sequences and so it

40:32 undergo cleavage. Okay. Now a recent, relatively recent 15, 20

40:41 um maybe 15, maybe 10-15 anyway crisper this system. Right again.

40:48 knowledge of this maybe more so from perspective of its use in medicine.

40:54 . To um uh edit human DNA that are have been mutated into some

41:03 of genetic disease. Okay. And they use these systems to whatever researching

41:10 I think there's there's some there already working actively working on some genetic diseases

41:15 fix it fix them by um providing proper sequence so that the team works

41:25 . But of course these were discovered bacteria and it's kind of a pseudo

41:31 immune system. Okay so the one about our immune system, adaptive immune

41:37 , the one that makes the antibodies it has memory to it.

41:43 We can that's that's the whole basis vaccination. Right? We can get

41:46 vaccine for a infectious agents and then that will protect us if we can

41:53 comes around again we can already mount quick immune response. And so the

41:57 aspect of the system is kind of analogous here with this christmas system.

42:04 , so uh let's look at the diagram that kinda just blown up and

42:12 out of piecemeal. So here would a bacterial virus affecting D.

42:19 A. Cell. And part of system is involved with cast protein.

42:26 short cascade protein. It has the to cleave D. N.

42:32 Okay. And it will do so on the viral D. N.

42:39 . And creating what's called a spacer is basically a short sequence.

42:45 And so this is put into the a region of the bacterial D.

42:50 . A. Right, so this essentially a catalog to each of

42:58 Okay. R. R memories if will of in the air quotes memories

43:06 prior viral infections, memories stored as viral sequences that have previously infected it

43:16 it chopped off a piece and put in there. So it's kind of

43:19 a of a library if you will viral previous viral infections. Okay.

43:27 so um so it collects those. , so what happens then through viral

43:35 , that system will be mobilized by that region. Okay. And so

43:42 RNA for that of course will then chopped up processed into the CRISPR

43:49 S. And so again these sequences will bind with the cast protein cascade

44:02 and presumably or hopefully right that depending the viral type infecting that one of

44:08 sequences will be complementary to the incoming sequence. Okay so of course if

44:16 virus was one of the type infected then it will have if not the

44:22 or very similar DNA. And that of those sequences will recognize it and

44:27 and the consequence of the binding to viral DNA is it will be cleaved

44:33 somehow maybe another way affect gene expression the virus so the virus cannot then

44:40 its life cycle. So a way counteract the viral infection. Okay so

44:47 I say memory kind of in a the sense that it has this collection

44:52 viral DNA is from previous infections and how it can kind of keep track

44:58 what's affected it before but it could the case that something could be different

45:01 and it isn't no help but it could. Um And of course now

45:10 we in terms of medicine it's used system is used to um uh target

45:17 sequences of human D. N. . And then um put the correct

45:22 in there. Okay um there's really question about that. Yeah. Yes

45:30 would truly. Oh it just gets the cascade protein. So this complex

45:38 right there. Well buying to the DNA and then that cascade protein breaks

45:44 . Yeah so that's remember they should say inactivation. Alright. You don't

45:50 see what's happening here. But what's is that DNA is getting we're

45:56 Yeah. All right. So now flip over to animal viruses. So

46:04 is the question to get us in direction. Okay. So the type

46:11 life cycle animal virus possesses is mostly by what. So again, this

46:17 to do with the fact that animal infect eukaryotic cells. Eukaryotic cells are

46:21 little more complicated. So it's gonna there's unlike a bacterial virus. There

46:28 be different destinations for a animal virus its host. Okay. So some

46:38 kind of what this is leading Mm hmm, mm hmm.

47:22 Mhm, mm hmm. Okay. . Yeah, I guess the the

47:41 and kind of different. But the does. Yeah, absolutely not.

47:49 . It's only know our system is even equate. The two are just

47:55 more complex. But this is very . Super baby. Super duper baby

48:08 . Mm hmm. Okay. So going to be, yeah, it's

48:16 to be the genome type DNA So that has to do with what

48:21 needs to copy that. And some those parts will be found in different

48:26 of the cell, so to So I'm being a little vague

48:29 But um you'll see as we go this. So um so we talked

48:36 host range and um trumpism. Remember the difference between the two hosts

48:42 How many different hosts can be Trumpism within a single host, how

48:48 cell tissue types can be infected? . And he's gonna be broad or

48:52 cold virus. Um is one that course effect effect sells the upper respiratory

48:59 . Um These kind of molecules are in our epithelial cells. Many of

49:03 are used for our epithelial cells kind buying to each other through various molecules

49:09 that this is one of them. so rhinoviruses exploit this particular one for

49:15 gain entry. Now the um the referring back to the genome type of

49:24 virus. So um the DNA viruses course utilized DNA polymerase to copy their

49:33 . Okay. And so why where you think it's gonna go? So

49:42 have different destinations for animal viruses in cell? Okay. So the virus

49:46 most likely go where because what's the for it? Well not just DNA

49:56 DNA polymerase. Okay. So recall the life of the cell cycle,

50:06 ? Of eukaryotic self. Right. in um s phase right, synthesis

50:11 when all the chromosomes get replicated and where the unemployment rate is gonna

50:17 It's gonna be a nucleus. And that's why many DNA viruses go go

50:22 for that purpose right now with all different groups we're going to talk about

50:26 are outliers. Right so there's actually DNA viruses that have their own DNA

50:32 ? Okay. Uh But yeah so talking most, most will follow the

50:38 , I'm about to show you. there will be outliers here and

50:41 Okay, um RNA viruses so remember have the RNA dependent RNA polymerase.

50:50 um they that's a that's not a thing. That's a viral thing.

50:55 those viruses will have that with Are the viruses. Except for retro

51:00 are the viruses that are non retroviruses have a need to go to

51:05 They can just do all their things . Okay. Um back to DNA

51:12 . So remember that, you know the barrio translation arrivals occurs outside the

51:17 transcription occurs inside the nucleus. Uh uh so with DNA and viruses are

51:24 of complicated because some stuff happens in nucleus. Some stuff happens outside the

51:29 . Things go back and forth. well, you'll see that it can

51:32 a little bit complicated for them. again, RNA viruses have their own

51:39 years, they just go inside of outside the nucleus and do their replication

51:44 . But again I mentioned, there's outliers in the RNA virus group flu

51:50 . Alright, the flu virus is that actually does do private cycle in

51:54 nucleus, not because it needs picker in there, but it just does

51:59 of the assembly in the nucleus. that that is an outlier retroviruses again

52:05 their own reverse transcriptase. And but they do integrate into the host

52:11 they do go to the nucleus. . So um now whatever the type

52:18 virus, the process of animal there is a process of once it

52:25 host and gets inside is um getting captured in genome in there.

52:31 And so depending on the viral it may do this at the uh

52:38 up as um at the outer membrane or it may do it at the

52:44 . It just depends. Okay. it may use a vehicle to do

52:48 or it may not. And so first example here is uh membrane

52:53 Okay, so uh enveloped virus can this like the measles virus. And

53:01 the envelope of course is a lipid layer just like the cytoplasmic membrane is

53:08 too are completely compatible. They confused each other. And so for types

53:13 do this, the envelope of the melds with the psychopathic membrane. But

53:20 that's always gonna be specificity, Except it's gonna bind specific. These

53:25 proteins bind to specific receptors and that the fusion with this host cell and

53:33 they captured is enters the cell. . And then quickly becomes uncoated.

53:41 can um it can sometimes bind with list ozone and digest it producing the

53:48 . Um sometimes it may have its enzymes to break it down. But

53:53 point is it's happening outside of the and Gm gets released now variation of

53:59 is using a vesicles in the Right so it's using the viruses using

54:06 the host cell uses for other Right? So for example the process

54:11 receptor mediated in those psychosis. That's ourselves used to bring cholesterol in for

54:18 . Okay. And so hepatitis C recognizes specific receptors on the surface that

54:27 um facilitate or will induce the endoscopy process. So they basically becomes

54:35 Bye. A vesicles. Okay then confused with license on and release the

54:42 . Okay. And uncoated. So encoding process again is to just release

54:47 free genome so they'll be copied. um the D. N. A

54:53 . Right so the first two are viruses. The coronavirus adenovirus will will

54:59 absorbed through endo psychosis formula vegetable Um and the process will be finalized

55:08 the nucleus. And so that's where genome is finally uncoated. Is that

55:12 nucleus right here? Okay so um you know they're all receptor very

55:21 Right, That host virus recognition. and depending on how it does the

55:28 , you know, it can be profusion of membrane endo psychosis or in

55:34 psychosis completed at the nucleus. Okay um now a couple of variations if

55:44 will of what ammo viruses can So uh the building of new viruses

55:53 um can occur. It often occurs the end of plastic particular um bob

56:02 are produced then go on to the . And so those so those organelles

56:07 be a part of the process for , um it was an enveloped virus

56:13 . Those viral proteins that are part the envelope. Right? Will be

56:18 and placed as you see here in membrane. Okay. And so as

56:25 cell virus exits it acquired, it around and acquires that envelope.

56:31 The process of budding. Okay. you see here. Alright, um

56:37 is a process that can occur at rates. It can be slow.

56:42 ? So there's a term called shedding like shedding hair. Right? Where

56:51 silken shed virus, they call So the host cell can be

56:56 Right? But at a lower rate these viruses budding off. Okay.

57:02 so the cell post up can remain in those cases of course this can

57:06 up and it can overwhelm the self you see different variations. Okay,

57:13 now the so this kind of side side comparisons here. Ok,

57:21 most most types will fit into their groups but as I mentioned, there

57:25 be outliers here and there that don't all the rules. Okay, but

57:29 didn't have viruses? Uh the nucleus typically a part of that process.

57:35 . Um the just because the way cells will work, you know,

57:41 can have translation outside the nucleus and inside the nucleus. So you're gonna

57:47 parts occurring. Um both both locations DNA viruses. Okay. Um are

57:54 virus is um general generally occurs all of nucleus and cytoplasm. Okay.

58:02 although again there can be variations Okay so let's uh look at an

58:09 of a D. N. A . This is papilloma virus. So

58:11 causes cervical cancer in women. There an effective vaccine for it though.

58:19 but it's being a DNA virus, ? It's one that goes to the

58:24 , it's one um that is So so it's been a virus can

58:32 be at the mercy of the host in effects. Okay. By that

58:37 mean tied to the growth rate of host cell. Okay so with the

58:44 of cells papillomavirus infects epithelial cells um cells themselves. Skin cells for example

58:54 differentiated. Right so you haven't called cells. Okay. But you're kind

58:59 the building blocks cells if you Right so basal cell well that differentiate

59:05 a correct site which is actually quickly fast growing cell. Makes your skin

59:10 of course you're are multiple layers and top layer of skin cells are constantly

59:15 reproducing because your sloughing off old cells replacing them. Okay so uh but

59:22 cells will not become critical sites until given chemical signals by the body.

59:28 so um so the papilloma virus that , right? Infecting a basal

59:36 Okay basil So it's not gonna be growing cell until it begins to signal

59:43 differentiate? Okay so the papilloma virus not going to really be replicating either

59:50 remember that nucleus contains DNA polymerase and cell type is not actively dividing then

59:56 know then the virus likely isn't rapidly . Uh That is um if it

60:04 on the host DNA polymerase, remember some DNA viruses that carry their

60:07 So they don't have that restriction But those that require the host plant

60:12 , they are at the mercy of host cell. Okay. So uh

60:18 with these basil types of cell papillomavirus can integrate. It's a DNA

60:25 that can integrate into the host Right? So ammo viruses that do

60:31 , they form what we call a virus. Okay, so the pro

60:37 to profane change. Except it's an virus, not a bacterium virus.

60:41 , so the pro virus state is integrated state violent genome in the host

60:47 . Okay. And so the and most likely to happen again in the

60:53 cells. Jack. So the uh depending on where that virus inserts itself

61:01 the chromosome that can affect, you , genes functioning genes. And so

61:07 all are aware that cancer is a of uncontrolled cell growth. Okay,

61:12 if it inserts itself in an area all about genes controlling soul growth.

61:18 then that can of course affect And cancer cells can result in that

61:25 And so but as the those that integrate in this fashion um or

61:33 But don't cause any issues as they into carrot. No sites. So

61:38 cell growth. So division. All is of course ramping up in the

61:45 cell division now now we're becoming got signal let's differentiate and we're gonna begin

61:51 grow. So then of course is HPD production as you see around here

61:58 . Okay. And so the cells shedding viruses at this point.

62:05 Um and so yeah it's a type that's tied to really the growth state

62:10 the hotel here because it dependent on preliminaries that it has. And so

62:17 we see PPV virus again double stranded virus um on coats at the

62:25 Okay relies on the host. Okay you see parks and cycle occurring out

62:32 translation into develop proteins that need to back into the nucleus and assembled in

62:40 and then exit nucleus and then the cell. Okay so um lots of

62:47 going on in different locations during its cycle. Um Any questions about

62:56 Yeah you're right. Oh the pro is analogous to the profile page.

63:05 both of those are aware the the DNA is inserted into the host

63:11 So they just they just were referring a animal virus. They call the

63:15 virus when it's a bacteria virus they it profane. But basically look the

63:21 . Did you have a question? you're going over the celebration.

63:33 That it's all about the rate of production for this guy of course depends

63:41 having DNA preliminaries to copy its And so in the basal cell formed

63:46 cells aren't really dividing. So you're seeing that enzyme really in the

63:52 And so when it's still begins to now you see it accumulate and that's

63:58 the HPV can can copy its own and initiate replication. Why why is

64:13 able to be what? Because it on the word, inserts in the

64:19 . So that inserts in the area involved in critical gene function particularly related

64:24 growth growth and regulation of growth. that's when it can cause cancer.

64:31 . Yeah. And I don't know that that HPV how specific it is

64:39 me. I think it's very randomly anywhere in the chromosome. I think

64:44 Land of Faith which has a very the site it goes to. I

64:49 I'm not 100% sure but I think can history you can insert randomly anywhere

64:55 think. You know I think I think so. Yeah. Okay that's

65:01 I mean. I think so in cases it can cause cancer in some

65:03 it won't depend on where it lands the chromosome kind of thing. Is

65:12 uh some I don't know what kind a combination it is. I don't

65:17 to speak. I'm not 100% sure . Yeah. Yeah. Yeah.

65:24 , yeah, yeah, that's how psychogenic viruses work is by that makes

65:28 retrovirus as well. Yeah. okay. So here's a question that

65:35 us into um, RNA viruses. . So yes. This concept of

65:41 plus minus R N a check. , um, so we have a

65:49 and granted granted this is a you know, simplistic kind of representation

65:56 a genome, but Just to keep simple. So hypothetical minus single stranded

66:01 virus is 10 rabbit nucleotides long. one below is most likely its

66:08 So hopefully right off the bat can one of these. Okay, they

66:15 left with two choices. And so choice then is having to recall what's

66:20 capability of a minus genome. When does the minus genome represent?

66:27 . What can, what can be with it? And that's really the

66:30 process. It also assumes you have kind of remember some of your intro

66:42 . This is how a transcript is into a pipe peptide. You have

66:49 remember that. Remember some of that too. Mhm. Mhm.

67:29 Okay, mm hmm. Here we . Let's see. Oops stock.

67:43 , Alright. About 50. So um, who answered?

67:54 why did you pick a see you terms of a key? Uh

68:14 maybe maybe on the right track. , anybody else? Yeah,

68:26 Starting crudo uh, yeah, we on the right track. So it's

68:35 a so if it were a plus which would it be? That's

68:42 Right. Because see can be directly into a protein. Okay, so

68:48 nature of the plus and minus So the mind plus genome is one

68:52 is the coding information. It can directly translated into protein. Right?

68:57 has the elements of the of translating sequence. Right? The AU

69:05 Star code on and so forth. . So and so and also remembering

69:10 a ribbon zone. Right. This our ribs. Um Right. five

69:15 to three crime is how they Okay. And so looking for the

69:21 G code on first and then So that's this is a plus

69:25 Right? That of course B. . N. A. Because there's

69:28 diamonds in RNA. Okay, so a plus strand with the code

69:33 Okay, the minus strand wouldn't have elements. Right? It will be

69:38 into as you were kind of leading would be copied into a plus

69:42 Right. And so this could be a this could be uh a Yugi

69:50 example that the three prime. So minus strand the clustering.

69:58 Um All right. So when we at I'll come back to that question

70:05 . Alright. Here escaped with the . Um All right. So you

70:10 Arnie virus. Okay, so remember two groups here the and what the

70:18 ? The deal conservative template for either . Which is the Plus RNA virus

70:24 um uh to make an actual Right, that's the minus genome.

70:30 it can be a retrovirus for its . Okay. And of course it

70:35 that route because retroviruses integrate into the chromosome. Okay, if it's going

70:39 do that it's gonna be D. . A. Okay. So um

70:44 let's look at the plus and minus virus. So it kind of at

70:48 beginning right? We kind of went it and so once more. Just

70:54 when I put this thing in I start with um showing first the

71:03 product. Right, This is what leading to. Okay, so um

71:10 are the virus is gonna make Franti looked like this. Right? You

71:14 to have multiple genomes, multiple obstacles protein. Right? Keeping it

71:20 We're just going for it could be course many more than that. So

71:25 nature of works. Right. The independent in the primaries, lots of

71:31 genomes. Okay, that was the . So again, it's the number

71:35 things. We have lots of Right? So lots of minus genomes

71:40 then cutting lots of pluses and these be simultaneously translated into protein and packaged

71:50 partners. Okay. So yeah, have to go this route because we

71:55 lots of genomes. Right. And can't copy this in the plus has

71:59 go plus minus plus. Okay, minus RNA viruses single stranded again.

72:07 the end product. What do we ? Lots of minus RNA genomes plus

72:12 . So we can copy that into multiple transcripts minus plus. Okay,

72:19 then simultaneously translate in the protein and into mind of strength because that's the

72:27 of virus it is. We're going package those into our parts.

72:33 So it's all about what's the viral is affecting and what's the end

72:40 Going to have to be lots of of genomes, lots of proteins.

72:43 depending on the genome type minus or , it's going to go through maybe

72:49 different routes to get there. But the end end game is the

72:53 . Make lots of projects. so um the the that's it.

73:02 maltese ruminating on this for a Um Any questions? So it's really

73:09 getting the plus minus steaks and comfortable that. Okay, so uh we

73:16 stop there and pick it up Thanks

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