| 00:19 | right. Yeah. Okay. Testing testing. Okay. Uh |
|
| 00:46 | just testing. Testing. It's not loud. Hold on. Testing. |
|
| 00:58 | . Okay. Um wait a Hmm. Testing testing. Testing. |
|
| 01:14 | as it usually is. All I'll shout. Um All right. |
|
| 01:20 | , uh so we continue on with genetics. Um So, let's kind |
|
| 01:26 | just think about big picture. in our context with microbes that cause |
|
| 01:34 | . Okay. So, um let's just know this. I forgot my |
|
| 01:42 | today. So, I'll just throw questions and we'll just answer um |
|
| 01:49 | Right? So, since bacteria produced binary fission, no one can assume |
|
| 01:53 | members of a given species are genetically , correct? No. We talked |
|
| 02:01 | that last time. Right? um you would think that by binary |
|
| 02:08 | that they might xerox machine just make copies. Okay. Doesn't work that |
|
| 02:13 | . Because they do have the ability um gain genetic variety. Okay. |
|
| 02:21 | we'll talk about those mechanisms today. talked about one last time which is |
|
| 02:26 | . Okay, So, mutation can the genetic code. Certainly creating variants |
|
| 02:31 | the population. So, in colonies a plate, right, Colonies on |
|
| 02:40 | plate. So, you look at millions of cells in that colony, |
|
| 02:45 | going to be uh 1% or so we're gonna have changes. Okay. |
|
| 02:50 | there be something that will you know of significance? Maybe? Maybe |
|
| 02:56 | But um because bacteria can spontaneously mutate a certain rate. May not crazy |
|
| 03:04 | , I mean, but higher than than we do. Okay. But |
|
| 03:10 | they grow so fast and we can , you know if there are changes |
|
| 03:15 | can see these in, you certainly in the short time frame. |
|
| 03:21 | . And so it's this kind of of of of genetic material by the |
|
| 03:29 | we'll talk about today are how a of these drug resistant types are now |
|
| 03:34 | um a particular bacterium acquires a mutation creates a resistance to a drug and |
|
| 03:42 | that is passed on and it's often on by these mechanisms. We'll talk |
|
| 03:46 | today horizontal gene transfer. Okay. so it can rapidly spread throughout the |
|
| 03:52 | . Ok. So many of your resistant types? That's how this |
|
| 03:58 | Okay, so um the so again horizontal gene transfer. This is |
|
| 04:09 | Okay. Just think mother to child you will. Right. That's how |
|
| 04:14 | inherited your genes. It's through vertical bacteria can also do do through um |
|
| 04:20 | so through horizontal gene transfer. And so um so let's look at |
|
| 04:32 | . So this diagram so the the big purple circle that represents all |
|
| 04:39 | the genes that we know of of the coal eyes that have been studied |
|
| 04:46 | analyzed in this way. So there's A little over 10,000 different genes have |
|
| 04:55 | found among all the allies that have studied. Um So of that |
|
| 05:04 | Purple. Okay a smaller set so coli so an average e coli |
|
| 05:12 | we'll have about 55,000 genes. Think of uh in a you've heard |
|
| 05:22 | gene pool. Right so all these there's there's many more genes among us |
|
| 05:27 | we don't have all the genes that out there. Okay that that are |
|
| 05:30 | by humans. But we have a gene pool. Right? Of |
|
| 05:35 | Right? So similarly here the average 5000. Doesn't have all all of |
|
| 05:41 | ones that are among all the coal . Okay. But it has about |
|
| 05:45 | . And then within that what we the smallest circle the red red circle |
|
| 05:52 | is genes common to every E. so every cola has those. It's |
|
| 05:59 | makes them an E. Coli. so things like and these are like |
|
| 06:03 | really critical function type stuff like DNA components code things that code for |
|
| 06:12 | The protein synthesis certain metabolic pathways that so aspiration. These are things that |
|
| 06:18 | common to all all members but certainly be differences. Okay. And so |
|
| 06:25 | it's really the the genes the genes aren't core genes, those other ones |
|
| 06:32 | ones that vary from the E coli are the ones that can that can |
|
| 06:37 | passed along through these horizontal transfer Okay and so the E coli genome |
|
| 06:46 | pretty much represents you know all bacterial for the most part in terms of |
|
| 06:52 | numbers you see here and don't worry memorizing the numbers but just to point |
|
| 06:57 | that unlike um our DNA the bacterial . N. A. Is much |
|
| 07:05 | most of the information is there to or something. Okay um remember that |
|
| 07:12 | any genome Not everything not every gene for a protein. Ok most do |
|
| 07:19 | you do have what we call genes ribosomes. RNA transfer RNA genes. |
|
| 07:29 | product of those is R. A. It's not a protein. |
|
| 07:32 | there are some of those but certainly coding genes are the majority uh and |
|
| 07:38 | a portion that's involved in control of genes. Okay so for humans it's |
|
| 07:44 | way different in humans. Only about is code for anything. Okay the |
|
| 07:54 | majority is involved in different types of and uh and really some a lot |
|
| 08:00 | unknown functions. So um way different precarious DNA but in any case so |
|
| 08:10 | focusing back on the differences. So have our E. Coli and um |
|
| 08:18 | are 22 strains. One is called . 12 K 12. Like your |
|
| 08:23 | lab E. Coli strain that you um The 0. 157 that is |
|
| 08:31 | um one that's been in a number outbreaks related to produce. So that |
|
| 08:39 | was one of those that was hit this restaurant contaminated spinach or salad or |
|
| 08:45 | . I forget what it was but it's responsible for a number of different |
|
| 08:51 | outbreaks. Okay and so if we at those two week allies and certainly |
|
| 08:57 | must be some differences. Obviously one disease one doesn't and so there's actually |
|
| 09:03 | more genes possessed by 0157 That 12 doesn't have. And those are |
|
| 09:11 | that are involved in uh causing Okay so excuse me. So um |
|
| 09:22 | again just to point out that uh this point that you know even though |
|
| 09:27 | coli eyes, you know like any replicates through binary fission, you think |
|
| 09:32 | they're all going to be the No gonna be definite differences. And |
|
| 09:35 | differences Uh can be attributed to the the acquisition of DNA from other |
|
| 09:43 | You see? 20%. That's a a large chunk of his genome. |
|
| 09:48 | been acquired from other microbes through these of conjugation, transformation et cetera. |
|
| 09:57 | um so here I just show you quick on the review of each of |
|
| 10:01 | will look at a little more detail some of these as we go along |
|
| 10:06 | . So so in this process there's source or donor of the D. |
|
| 10:14 | . A segment. And so um so we're talking about the nature of |
|
| 10:22 | here, operative word is fragment. , we're not transferring an entire chromosome |
|
| 10:29 | in any of these processes. We're a piece of it. And so |
|
| 10:36 | can be a circular form. Uh can be in a linear form. |
|
| 10:41 | , circular form would be something like plasma. And we'll talk about |
|
| 10:45 | Um Let's see all these four Okay now a very important process that's |
|
| 10:53 | in all these is recombination, This this donor DNA will match up |
|
| 11:08 | parts of the chromosome and become a of that chromosome. Okay so recombination |
|
| 11:16 | that happen. Okay. So so a piece of it's a linear piece |
|
| 11:23 | DNA. Okay. Like that. this. Okay. And that gets |
|
| 11:31 | a cell. Like you see there lifetime of that fragment is going to |
|
| 11:37 | very low because the cell is probably think it's a viral infection going |
|
| 11:42 | I'm just gonna get rid of Okay. And so if it's going |
|
| 11:46 | exist it better recombine with the chromosome become a part of the chromosome then |
|
| 11:52 | will be able to stay in that . Okay. If it's a circle |
|
| 11:57 | form, these don't have to So it can exist like if that's |
|
| 12:07 | donor D. N. A. can exist as a circle in the |
|
| 12:09 | . Right? So the cells sense when there's a linear piece of |
|
| 12:15 | That that's not normal. Okay. probably represents a viral infection going I'll |
|
| 12:20 | about viruses. I think next But but when it's a linear piece |
|
| 12:25 | D. N. A. And how the bacterial. So that's weird |
|
| 12:28 | it. Let's put it that way that's doesn't look right. I'm getting |
|
| 12:31 | of it. Right? But there's to still recombine possibly. But um |
|
| 12:36 | if it's a circular piece that doesn't weird. And so plasmas are that |
|
| 12:41 | and they can be they can exist way. Okay so but but recombination |
|
| 12:49 | a part of um is a part all four of these processes. |
|
| 12:57 | transaction conjugation, transformation. And even the circle form we'll see in the |
|
| 13:04 | form. But it can exist out . Just stay out here outside the |
|
| 13:10 | . Or it can recombine with that as well so it can actually combine |
|
| 13:17 | become part of the chromosome. We'll that too. So those variations are |
|
| 13:21 | possible. Okay so by recombining then that molecule the donor DNA becomes a |
|
| 13:30 | part now of that chromosome. Um and in the process of course |
|
| 13:38 | recipient is you know could be receiving new jeans right? Or maybe jeans |
|
| 13:46 | it has already but they're kind of and so by getting acquiring new new |
|
| 13:51 | of them, it can fix those . Okay so there's different uses for |
|
| 13:59 | uh this D. N. Okay so here are the mechanisms. |
|
| 14:05 | so transformation so the way that each is fairly easy to characterize in other |
|
| 14:14 | you can you can break down the types by just a couple of |
|
| 14:18 | Okay so for transformation it's simply just uptake of DNA from the environment. |
|
| 14:24 | it. There's nothing really more Nothing more complicated than that. Okay |
|
| 14:29 | and again these are gonna be fragments DNA that's in the environment of course |
|
| 14:33 | from you know cells that an environment you die. When you die they |
|
| 14:38 | and whatever is in them spills out the environment. And DNA fragments to |
|
| 14:43 | chromosome. And they sell will not has a finite life in staying as |
|
| 14:49 | intact chromosome breaks up environmental conditions or . So there'll be fragments in the |
|
| 14:56 | and those are potentially can be taken by cells. And so that's what |
|
| 15:00 | call transformation. Okay. Conjugation Now two selves coming together and there's a |
|
| 15:09 | for that happening. A one of pill I um cells that can do |
|
| 15:15 | have a special sex pilots that connects two cells and is through there where |
|
| 15:23 | will copy a part of this is through plasmid transfer. Okay. And |
|
| 15:30 | copy will be sent to the recipient transaction virus. That's the key for |
|
| 15:37 | process is a virus is the one the intermediate. Okay, so viral |
|
| 15:43 | occurs and when that virus affects another , what happens is in the process |
|
| 15:51 | virus accidentally by mistake packages host DNA of host DNA. And then when |
|
| 16:02 | infects another cell now it's given it piece of DNA. So the virus |
|
| 16:08 | the one that's carrying it across. , transposition the process involving these mobile |
|
| 16:19 | elements, small segments um and transpose are in all life forms. We |
|
| 16:27 | them as well. And they kind they used to be called jumping |
|
| 16:35 | They would uh come out and then insert themselves in a different part of |
|
| 16:40 | chromosome and that's what they do. They generally just move around the |
|
| 16:47 | Yeah. So that's it only happens the sex pilots. Only happens with |
|
| 16:59 | . Yeah. Um transposition. So the normal processes the transpose on kind |
|
| 17:09 | just flips and flops around chromosome. that high rate but it does that |
|
| 17:14 | . Okay. But there can be when that transpose on hitches a ride |
|
| 17:23 | a plasma and then that's the So it kind of combines with conjugation |
|
| 17:30 | get it transferred. Okay. And and then that new cell can acquire |
|
| 17:37 | gene or genes are on this Ok, so top to bottom it's |
|
| 17:45 | uptake of naked DNA doesn't involve anything . Conjugation. two cells coming together |
|
| 17:54 | the virus transposition transpose on. So we'll look at some of these |
|
| 18:01 | or less detail. Starting with Yeah. Well not quite. So |
|
| 18:12 | this is um the fate of N. A. Acquired. |
|
| 18:16 | So I kind of mentioned this But so here's external DNA that comes |
|
| 18:23 | and you know, it could be food source, right? You can |
|
| 18:26 | down nuclear tides. That's carbon carbon you can eat that. So you |
|
| 18:30 | do that. Um certainly can recombine the chromosome. Okay, recombination. |
|
| 18:39 | ? And now it's acquired these segments DNA. Right? So um I |
|
| 18:46 | coexist right Either um as a class outside the chromosome you see here? |
|
| 18:56 | it could integrate. Right? This integrate into the chromosome. Right? |
|
| 19:01 | or it could be degraded, Could be degraded users. So those |
|
| 19:06 | kind of three faiths. Especially if a linear piece of DNA coming |
|
| 19:13 | You're gonna be more susceptible to Getting eaten part. The cell actually |
|
| 19:19 | it's probably a viral infection. But it could recombine before anything happens to |
|
| 19:25 | . Okay. Um Okay. And this part here is just it's just |
|
| 19:33 | show you I'm not going into any here. But the main the main |
|
| 19:41 | involved in this is this wreck a stands for recombination recombination. A |
|
| 19:49 | Okay so this is so there has be some you can't take two completely |
|
| 19:58 | um D. N. A pieces make them come together. There has |
|
| 20:03 | be some some level of hm Right? So remember it's all about |
|
| 20:11 | . A. G. C. . T. C. G. |
|
| 20:15 | . Write the base base pairing. , coming together base pair. That's |
|
| 20:20 | it is. So it has to some some commonality in terms of base |
|
| 20:24 | that are common where the where the can begin to recombine with the |
|
| 20:30 | Okay so that'll be some level of complementary base pairing between the two. |
|
| 20:37 | um and so direct aid actually helps out. Direct a takes hold of |
|
| 20:44 | end and begins to look for Where is that similarity Where where I |
|
| 20:49 | start um complementary base pairing and make a part of the chromosome. Okay |
|
| 20:56 | again if it if it does happen as you see here then it could |
|
| 21:03 | a it could insert itself where there a non functional form of that gene |
|
| 21:09 | now it's functional. Okay so repairing a defective gene, it could be |
|
| 21:15 | new gene doesn't even have and so can give it some new features. |
|
| 21:20 | But of course it's by acquiring this D. N. A. It |
|
| 21:25 | create a variation within the population. um so again with all four of |
|
| 21:33 | processes this this is a big part of of it being successful. |
|
| 21:40 | Combination. Okay. Um Okay so questions while you're reading this? Okay |
|
| 21:50 | transformation is asking about transformation? Right this requires that it requires cell to |
|
| 21:57 | contact. If you think yes raise hand as it required a viral intermediate |
|
| 22:07 | a sex pilots. Does it require plasma? Does require DNA fragments in |
|
| 22:14 | environment? Yeah the other choices here days we haven't talked about that's involved |
|
| 22:21 | transposition. So it's E. Transformation E. Okay and there's other terms |
|
| 22:31 | with transformation. And so this way um the transformation was found out even |
|
| 22:44 | it was not even known what DNA in terms of inheritance at this |
|
| 22:51 | early 1900s and so um what was was using a particular bacterium, streptococcus |
|
| 23:02 | , which is the most common cause bacterial pneumonia. Okay. Um and |
|
| 23:09 | actually two forms, there's a a that causes a full blown disease. |
|
| 23:17 | then there's a form that is a that doesn't and for this bacterium, |
|
| 23:25 | thick capsule is part of the way crosses disease. It enables it to |
|
| 23:33 | from the immune system etcetera. So a capsule for this guy is essential |
|
| 23:38 | it to cause disease. And so mutant form doesn't have that. |
|
| 23:42 | And it gives it a what's called rough appearance. So they typically call |
|
| 23:46 | the rough and smooth, smooth encapsulated . And so you see the over |
|
| 23:55 | the S form or smooth is is pathogen and the rough is lacking the |
|
| 24:03 | . So when we inject mice with smooth form, the mice mouse dies |
|
| 24:07 | pneumonia, the one with the rust is fine. No problem. So |
|
| 24:13 | he kind of did some mixing and here. And he first took heat |
|
| 24:21 | encapsulated uh bacteria as smooth types. heat inactivated them injected and the mice |
|
| 24:31 | not um die. They weren't viable . And so when he mixed these |
|
| 24:41 | heat killed types alright from here and them with the live rough mutant cells |
|
| 24:51 | didn't cause disease. Then he whoa objected in the mouse and is |
|
| 24:56 | . Okay, so that's where he this phrase transformation stating that the dead |
|
| 25:05 | captivated cells here we'll certainly have Okay. And their DNA would have |
|
| 25:12 | into the surrounding medium. Okay. then that D. N. |
|
| 25:19 | Fragments would have been taken up by cell, transformed it transformed it into |
|
| 25:27 | deadly cell cell type. Okay. so they would have been a fragment |
|
| 25:33 | that capsule gene and maybe some other genes to be a pathogen took it |
|
| 25:40 | re combined and boom it became now disease causing type. So it transforms |
|
| 25:48 | . That's they called they called it D. N. A. So |
|
| 25:52 | called the thing that moved from cell cell the transforming principle. Okay. |
|
| 25:58 | course they found out uh not long that that actually was D. |
|
| 26:03 | A. That was doing the transfer in this. But um but that |
|
| 26:10 | of course the first example of horizontal transfer. Okay and so the process |
|
| 26:21 | . Okay again up take a naked . So competence is a word you |
|
| 26:28 | with transformation and only with transformation Right? When cells are competent, |
|
| 26:35 | are ready to take up DNA. you shouldn't get the idea that Number |
|
| 26:43 | , not all bacterial types can do . Okay. Um those that do |
|
| 26:52 | it are capable of it aren't in state of being able to take it |
|
| 26:56 | all the time. Okay. So have to become competent first and that |
|
| 27:04 | different kind of chemical signals and stuff not gonna get into but just know |
|
| 27:10 | um they have to be in a of readiness to do because there's certain |
|
| 27:15 | that have to be synthesized in the to help them take into DNA. |
|
| 27:20 | it's kind of about that. Um so it's not just any cell |
|
| 27:25 | just suck it up out of the . No it's a complicated process it |
|
| 27:30 | involves different parts to help take it and whatnot. But when you're in |
|
| 27:34 | that state to be ready then you're . Right? So um now in |
|
| 27:39 | lab the E coli is used all time for this. So the techniques |
|
| 27:46 | you may have heard of cloning right? Competent D. N. |
|
| 27:51 | . These kind of things you do lab to manipulate genes in order to |
|
| 27:56 | them. Okay, transformation is a part of that because you're taking a |
|
| 28:02 | and you're using that cell to make of your D. N. |
|
| 28:05 | Okay you have to sell copy your and make lots of it that you're |
|
| 28:10 | but you have to get in there use transformation, do that. So |
|
| 28:14 | coli does not do this naturally there called uh so that naturally do |
|
| 28:23 | And cells that can't you have to make them competent. Okay you can |
|
| 28:29 | chemicals, you can use electric These are processes that will force the |
|
| 28:34 | to take it up when it normally . And so in lab that you |
|
| 28:39 | of do those things, We've made coli our blank. Okay. You |
|
| 28:45 | think of the right word there. not gonna say it. We've made |
|
| 28:49 | it our you know what in the right? To make it make it |
|
| 28:52 | what we want to do with Right. And so kind of forming |
|
| 28:55 | is one of those things because you how to grow and grow it fast |
|
| 28:58 | it's a good vehicle to get our . N. A copied. |
|
| 29:04 | So anyway um so you know with um transformation, the keys are being |
|
| 29:15 | . Okay. There are cells that take this up but they have to |
|
| 29:20 | competent first. They do they take in recombination is going to be a |
|
| 29:24 | part of this because they're generally taking linear fragments of DNA from the |
|
| 29:30 | So it had better be able to with that chromosome. It was going |
|
| 29:34 | become a permanent part of that Okay. Um And so so that |
|
| 29:41 | aren't naturally competent, we make them . And again, we only do |
|
| 29:46 | only do artificial transformation for our own obviously. Right? It's not something |
|
| 29:56 | it's for resource purposes. What have ? Okay. Um If we want |
|
| 30:01 | express a gene in a certain type bacterial cell and it will not naturally |
|
| 30:08 | , then we make it do Alright. That's the only kind of |
|
| 30:10 | we do artificial transformation. Okay. Any questions about transformation? Okay. |
|
| 30:19 | right. So plasma so plasmas gets into conjugation then. Okay. Because |
|
| 30:26 | how they're these are transferred. So are small circular extra chromosome. |
|
| 30:35 | pieces of DNA generally there's like you'll various ranges and books and whatnot in |
|
| 30:43 | experience um I work with sizes that generally around 5 to 10,000 bases. |
|
| 30:54 | that on average is is what most . But you can get some that |
|
| 30:59 | on the extreme ends even upwards of base pairs. But regardless um it's |
|
| 31:07 | much smaller than the chromosome is of . Okay. And so it'll carry |
|
| 31:11 | few genes on and one of the ones is boxed in original replication and |
|
| 31:21 | for short original replication we have them our chromosomes multiple. It's it's the |
|
| 31:30 | where DNA begins to be replicated. ? So if a D. |
|
| 31:34 | A has an ori it can be . Okay. It has to have |
|
| 31:39 | ORI origin replication to be able to copied and because plasmas have those have |
|
| 31:46 | own they can copy themselves. Okay plasmas work independent of chromosomes. So |
|
| 31:55 | chromosome remember will only replicate when the is going to divide. Right, |
|
| 32:01 | don't have that restriction. They don't about that. Right. They can |
|
| 32:05 | copy themselves as they want. autonomous we call it. Okay. |
|
| 32:13 | so it's plasmids that can be what called conjugated if it's a conjugated |
|
| 32:20 | that word means it can be copied transferred to another cell. Okay. |
|
| 32:27 | there are parts of the plasmid that to be present for that to |
|
| 32:33 | Okay. So there's multiple genes involved that as you see here, that |
|
| 32:40 | pilots and conjugation proteins in that segment of transfer. So we have an |
|
| 32:50 | when specific for making copies of the . We have another type down the |
|
| 32:57 | that's specific for when it's going to transferred to another cell. Hence origin |
|
| 33:03 | transfer. So it will copy from when congregations going to occur and it's |
|
| 33:09 | to be copied and passed to another . Okay, so it's cells that |
|
| 33:16 | like this right cells that have this . We call them F factors. |
|
| 33:24 | the F factor is actually the parts involved in conjugation. Okay. That |
|
| 33:34 | is essentially the effect of the parts make it be able to be |
|
| 33:38 | Okay, because that factor will have genes with it besides that. |
|
| 33:44 | So you can see on here we these things this this this this this |
|
| 33:53 | and and let's see yeah, so and here is tet right, that's |
|
| 34:07 | resistance. Right? And so these these other other designations are sites where |
|
| 34:16 | can cut the platform but there's also for different antibiotics. Tetracycline is one |
|
| 34:22 | them. Okay, so this thing be since it has the f |
|
| 34:27 | right? It can congregate then this be passed on and the next cell |
|
| 34:31 | inherit Tetracycline resistance put plus whatever else on there. So again it's obvious |
|
| 34:41 | when this is transferred all the genes there are ending up in other cells |
|
| 34:46 | they can express their basically spreading those right throughout the population this way. |
|
| 34:54 | what are the types of genes on besides antibiotic resistance that they call those |
|
| 35:01 | plasmids or are factors okay if it that violence genes so things like and |
|
| 35:10 | certain toxins um uh maybe uh jeans a pillar or something, structures that |
|
| 35:19 | disease to occur can be passed on plasma. Cata bolic genes. So |
|
| 35:24 | a metabolic pathway. Genes for metabolic are on there. That's not |
|
| 35:30 | So um and so the other point is of course it's it's it's a |
|
| 35:35 | a few genes are being carried on plasma. Okay. And so um |
|
| 35:40 | can potentially be passed on and other can inherit it now. Um artificial |
|
| 35:52 | , these are ones we've constructed in lab for our own purposes. So |
|
| 35:57 | just mentioned the term cloning genes We we construct plasmids to have the |
|
| 36:03 | we want in them and to this and age is relatively easy to |
|
| 36:09 | Okay. But it's a way to of control everything. So we can |
|
| 36:16 | experiment with what we want to okay constructing it. So so the |
|
| 36:24 | okay, is uh involved again? parts one of them, of course |
|
| 36:32 | pilots and the sex pilots recall um pilots in the context of twitching |
|
| 36:42 | right? It would send out a , it would stick to a |
|
| 36:47 | then it would diploma rise shortened and would then as a result move that |
|
| 36:54 | similar with the sex pilots. You elongate by adding more substance to it |
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| 37:02 | you can shorten it by taking them and so it actually draws the |
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| 37:08 | So you have a donor and Okay. And so what we called |
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| 37:13 | . Plus is a donor. So an F. Plus F mice. |
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| 37:21 | initially there may be farther apart, when the pilots connects to it, |
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| 37:26 | draw itself in closer. Okay. that's as you see here. |
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| 37:34 | And so that that's because that pilot not exactly um it's fragile. |
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| 37:43 | So they say this part of this apart is more much more likely that |
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| 37:48 | occurs and it disrupts the process, ? So by connecting and bringing together |
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| 37:53 | much more stable connection. Okay so time there's enough time for significant amount |
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| 38:00 | being passed between them. Okay? you know, I'll show I'm gonna |
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| 38:05 | you an animation of this as And so then of course I'm gonna |
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| 38:11 | so this is what we call just basic um F. Plus two F |
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| 38:18 | cell conjugation and the F minus ends as F. Plus. Okay, |
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| 38:24 | we're gonna copy the they come they form what's called a conjugation bridge |
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| 38:30 | them. The defector gets copied and copy gets put into the recipient |
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| 38:40 | And now the F minus has become . Plus. Okay. And so |
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| 38:50 | let me before I talk about so let's stop there and let me |
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| 38:53 | the animation. Okay. Uh Not one. He's my other one. |
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| 39:08 | see. No, no. Uh gotta get my other, hold on |
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| 39:20 | second me back out of this Okay. Right that one. |
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| 39:38 | so here's our effect. Er So so we not that again. All |
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| 39:52 | . It may be because of So let me try this, hold |
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| 39:58 | . Um Okay uh back, Alright, so I gotta do something |
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| 40:17 | up with the video. Sorry about , I'll get it working next |
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| 40:20 | So that's just a couple of So in the video you would have |
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| 40:28 | is basically the same thing here, kind of all happening in motion. |
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| 40:33 | we see that when they conjugate. , this one actually had a friend |
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| 40:41 | on it. Okay. And the was passed in between and okay, |
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| 40:57 | then it inherited, so that's a . This F minus inherits chromosome and |
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| 41:06 | we see. Okay, that's the minus, that's become F. |
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| 41:17 | Okay, there's the F. Factor we see them in the video that |
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| 41:27 | like a chia pet. The hair pop up. Okay. The bottom |
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| 41:33 | meaning that as as that thing inherited then expressed what was on there. |
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| 41:38 | apparently there was a genius. And then the F minus cell gained, |
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| 41:44 | that function. Now it's full Okay. Just the point. You |
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| 41:48 | that whatever is on that plasma, genes can be expressed in the recipient |
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| 41:52 | and then expresses those new traits Okay so the other thing to notice |
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| 41:58 | that um because we're going to see process next, that's a little bit |
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| 42:04 | . But the important point here is the F. Plus is carrying that |
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| 42:09 | factor outside the chromosome. Right? in in what we call an |
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| 42:14 | F. R. Formation, so formation of HF are um requires doesn't |
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| 42:24 | virus. Alright so virus transaction nothing . Okay uh It would um it |
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| 42:32 | require actually it wouldn't require DNA fragments the environment. That's transformation. |
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| 42:39 | Um it wouldn't require transpose is that's . Okay so eliminate those right off |
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| 42:45 | bat out out. Um It um really a F. Factor integrated into |
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| 43:05 | chromosome. Okay so it already is F. Plus plus cell F. |
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| 43:13 | cell. But the F factor isn't outside the chromosome by itself. It's |
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| 43:20 | the chromosome. Okay so it's still plus. It's just in this integrated |
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| 43:25 | we call it HFR. Okay and it looks like this. So we |
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| 43:34 | an F. Plus cell and at frequency. Okay. At some frequency |
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| 43:41 | process happens where the plasmid there's recombination . Recombined with the chromosome. |
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| 43:49 | And now it's integrated. Okay. that's an H. F. R |
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| 43:54 | . Okay. And those that can that now now is the the integrated |
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| 44:05 | plus inside the chromosome means that now entire chromosome can be copied and |
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| 44:13 | Okay. But that rarely if ever . And there's a main reason for |
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| 44:22 | . Okay. So here's a congregation H. F. R. And |
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| 44:27 | minus. All right. So it involves having to have an F minus |
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| 44:33 | . So again so the difference here course is we're copying and transferring. |
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| 44:38 | a small plasma but the big Okay. And the um the reason |
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| 44:50 | the entire thing isn't copied and It depends on how long those cells |
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| 44:56 | together for an E. Coli chromosome is on the upper end range of |
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| 45:02 | chromosomes. In terms of size It's five million five million base pairs. |
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| 45:10 | would take over 90 minutes to transfer entire thing and they don't hang around |
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| 45:17 | long. Okay. Together. Generally you know, you can have Even |
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| 45:25 | the lab-controlled conditions where you minimize vibrations that kind of a thing. |
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| 45:31 | in the room it's you know I'm say on average probably about 20 minutes |
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| 45:36 | 40 minutes is the range at which hang together not much longer than |
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| 45:41 | So what that means is um you copy the entire chromosome and all the |
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| 45:48 | into another cell. A portion of gets there. And so so here |
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| 45:54 | can see you may not be able see it very well but the portion |
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| 46:00 | was transferred and the recipient cell was this much. Okay that block that |
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| 46:10 | of material was transferred. That's and relates to how long they stuck |
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| 46:16 | Okay. Um so you can right so this is the f minus |
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| 46:25 | HFR F minus And it's still an minus. Okay so it acquired the |
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| 46:36 | of the of this new D. . A. But it didn't become |
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| 46:40 | F plus like it did in the mechanism. Okay because back here the |
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| 46:49 | here the entire the entire plasma was . Okay. To the whole thing |
|
| 47:03 | transferred to the other cell. And meant because remember that factor is all |
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| 47:08 | parts to be able to congregate. ? It's what makes it an |
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| 47:11 | Plus. So the entire F plus up in the f minus cell making |
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| 47:18 | that plus. Right? But in conjugation. Okay the um the parts |
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| 47:32 | f. Part F plus F plus of of this chromosome continue the F |
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| 47:40 | right? Is at the very end the chromosome. Right? So it's |
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| 47:46 | the very end of it. So don't stay together long enough for the |
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| 47:52 | minus to inherit the F factor. . That would enable it to be |
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| 47:58 | congregate. Right so all the Plus means the cell is F. |
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| 48:05 | . That means it's capable of copying transferring that factor. Okay It means |
|
| 48:13 | can congregate and pass it on. right. But it has to have |
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| 48:17 | parts. It has to have the pilots gene and it has to have |
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| 48:21 | other components specific to that process. in the HFR those parts are located |
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| 48:28 | the very end of the chromosome. last part that would be transferred and |
|
| 48:32 | don't stay together long enough for the to get that. But just because |
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| 48:38 | F minus here did not inherit It's not it's not horrific. Okay |
|
| 48:44 | it. Yeah it can't congregate that but it's still inherited. No this |
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| 48:52 | segment of D. N. And it can divide by binary fission |
|
| 48:57 | pass it on that way. Okay it don't take it to me and |
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| 49:02 | a negative because it's not it's still potentially acquire new genes. It just |
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| 49:07 | pass them on to conjugation. It'll to rely on vertical transfer. Right |
|
| 49:12 | fission to do that. Okay and it's all it's only because of the |
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| 49:19 | of where those F. Plus the . Plus part of that thing is |
|
| 49:25 | it's just at the very end in and it doesn't get transferred. There's |
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| 49:28 | enough time for that to happen. um Any question about that. Okay |
|
| 49:41 | transaction. Okay Virus Easy one transaction a virus we haven't talked about viruses |
|
| 49:51 | . We will. So let's look the process of what we call generalized |
|
| 50:00 | . Okay so we'll learn I guess week that um with bacterial viruses like |
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| 50:10 | virus writer virus infects a host right a host to replicate itself. So |
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| 50:18 | material virus begins by recognizing the host to it and then inserting its |
|
| 50:27 | Right? So that's what you see it's fate attachment. Then you see |
|
| 50:33 | viral genome entering the cell. Okay of the steps that occurs is that |
|
| 50:39 | virus begins to break down the host . It actually uses it. It |
|
| 50:47 | the nuclear tides from that to make own D. N. A. |
|
| 50:51 | nonetheless the host DNA. Is fragmented the virus. Okay then part of |
|
| 50:57 | stage of any viral life cycle is copies of my genome and make viral |
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| 51:06 | and assemble everything. Making new Okay now and part of that process |
|
| 51:12 | what's called packaging right is taking the DNA. That's been made and then |
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| 51:19 | into a virus structure to make a virus. Right well what happens at |
|
| 51:26 | low frequency that an error is made that packaging and so host. So |
|
| 51:33 | see your bacterial donated darker purple. so here's the host D. |
|
| 51:41 | A. In the dark purple. that got packaged instead of viral |
|
| 51:49 | Okay so host DNA got packed into viral DNA. Okay so now that |
|
| 51:59 | fage the fage can still infect another . But it's just not passing along |
|
| 52:06 | it's not inserting its chromosome. It's inserting the DNA of the previous |
|
| 52:11 | Okay so bacterial DNA. Is being . And so um here is so |
|
| 52:22 | then that host D. N. . Which would be there would recombine |
|
| 52:31 | that new host and become a part that new that new hosts DNA. |
|
| 52:41 | so you know obviously the virus was the virus was the mechanism to get |
|
| 52:46 | D. N. A. In in the next host. Okay and |
|
| 52:49 | course that cell can divide and then that those genes on to future |
|
| 52:56 | Okay and so um again all facilitated by this viral infection that was the |
|
| 53:05 | of this. Okay and so um in this generalized transaction theoretically any any |
|
| 53:18 | these DNA fragments from the host could been packaged. Okay what that means |
|
| 53:25 | potentially any gene in that original host have been transferred. Okay any |
|
| 53:34 | Right so it's very non specific. what they call it generalized. Okay |
|
| 53:40 | there is a process called specialized Okay so generalized any host I mean |
|
| 53:46 | any segment here can be packaged accidentally passed off. Okay and specialized transaction |
|
| 53:54 | the more complicated. We're not going go into details of it. But |
|
| 53:58 | specialized transaction there's only a select few are transferred. Okay so it's much |
|
| 54:04 | specific. Much more narrow in terms the types of genes that can be |
|
| 54:09 | compared to generalized transaction. But nonetheless toxins you see there are passed along |
|
| 54:16 | specialized transaction. Um The uh just I'll just say that um specialized transaction |
|
| 54:28 | due to, well it actually become when we get to next week and |
|
| 54:34 | talk about these things but there's a virus type. Okay that actually let's |
|
| 54:44 | it like that. Okay. Fage . N. A. Host |
|
| 54:54 | N. A. Here and So the bacterial virus has inserted itself |
|
| 55:01 | D. N. A. Into host chromosome. Okay that's what it's |
|
| 55:05 | . That's that's where you see the transaction where this fage puts its genome |
|
| 55:12 | the host genome. Okay. And happens is at a low rate it |
|
| 55:19 | come out of that host. And normally what happens is so the this |
|
| 55:30 | the viral D. N. And that's what would come out just |
|
| 55:35 | but at a very low rate what is that comes out comes out cock |
|
| 55:42 | . Okay so in other words it out here to hear instead it's shifted |
|
| 55:50 | little bit to one side or the . And so now you see that |
|
| 55:56 | there's host DNA. All right so little a little portion on one end |
|
| 56:03 | transferred with that virus right? Or could be shifted the other way and |
|
| 56:10 | this portion maybe it's transferred. And so that's what it's only it's |
|
| 56:16 | a one side or the other and a small portion so it's very selective |
|
| 56:21 | terms of what gets transferred. So fewer than than generalized transaction. And |
|
| 56:29 | because of the way the page integrates when it comes out it takes a |
|
| 56:33 | bit of peace because it does it out clean? Okay. But again |
|
| 56:39 | see that next week. But that's of how specialized transaction is different. |
|
| 56:46 | um so the transaction virus the virus the go between. Okay um transpose |
|
| 56:56 | . Okay so these um naturally occur all species I'm pretty sure um They |
|
| 57:11 | and they typically move around within the individual species. Cell move around within |
|
| 57:22 | same cell in the in the same chromosomes. Okay. At a low |
|
| 57:29 | as you see there. Okay and a. Um and this is brought |
|
| 57:36 | by an enzyme called a transpose okay so the simplest of these is |
|
| 57:44 | called an insertion sequence. Okay S. And so you see the |
|
| 57:53 | gene which is translated into the transposed and that enzyme is what produces cuts |
|
| 58:05 | the in these sequences called inverted Okay and so we call it that |
|
| 58:15 | if we look at this sequence. . A. T. C. |
|
| 58:20 | . G. T. A. we look at it here it's the |
|
| 58:26 | A. C. T. A. But it's just been |
|
| 58:30 | So hence inverted repeats. Okay and that's that's recognized by the transpose so |
|
| 58:37 | can cut itself out and then insert somewhere else on the chromosome. |
|
| 58:44 | Um Now a more complex form has at the top plus one or more |
|
| 58:53 | . So this one is carrying Okay so you see the I. |
|
| 58:59 | . Ones are now on either right in the middle is um Another |
|
| 59:07 | can be more than one but Um and T. and five is a |
|
| 59:11 | transpose on. That's that's one that does carry that Um antibiotic resistance. |
|
| 59:18 | so there are a few like n. five that carry resistance to |
|
| 59:23 | antibiotics. Okay I think some of are found in the bacteria that causes |
|
| 59:31 | . Mycobacterium tuberculosis has a transpose on it that that confers antibiotic resistance. |
|
| 59:40 | . Um so now moving around, So normally these things just move around |
|
| 59:48 | the same chromosome in the same cell that's all they do. Okay. |
|
| 59:54 | they may hitch a ride. Okay so they hitch a ride with a |
|
| 60:03 | . Okay so here is a chromosome that T. N. TN is |
|
| 60:13 | for transpose. Um Okay so here's transpose um in the chromosome chromosome and |
|
| 60:25 | is a plasma. Okay and so could be the jumps into the |
|
| 60:36 | And so now if that Klansman is an F factor and can conjugate then |
|
| 60:46 | can be transferred. Okay plasma is now transpose on can pop out and |
|
| 60:56 | back into the chromosome of the next . Okay so um uh the and |
|
| 61:07 | that's how it transports are gonna be outside the cell to something else. |
|
| 61:11 | so it kind of piggybacks on Uh But you know is now now |
|
| 61:18 | this new cell. Okay. And um with all these mechanisms these four |
|
| 61:25 | , that's how you know antibiotic resistance gets gets takes hold okay and spread |
|
| 61:32 | the population. Okay. Um Okay let's see what we can match up |
|
| 61:44 | which process. Okay so take a at that. And so with |
|
| 61:52 | Okay virus goes with which let's start this school with the left. So |
|
| 62:00 | , What's going to be part of ? Which which numbers uh did you |
|
| 62:14 | ? Which one? Seven? Okay we're talking about conjugation now, |
|
| 62:24 | six. Yeah. Anything else, . Anything else? Three, |
|
| 62:38 | 6 5 and three. So I'll C. For congregation. Okay transformation |
|
| 62:49 | . 1 1. Yeah. Uh go T. F. For |
|
| 62:57 | Anything else? Yeah to to Okay um And anything else? Some |
|
| 63:14 | used more than once. Okay wait get something's not right here. Yeah |
|
| 63:25 | not right bad bad me bad. ? Okay so um yeah somebody said |
|
| 63:38 | , transformation. Let me do this Competence to seven. So we had |
|
| 63:51 | and six six. Okay um Trans . Yeah of course. No |
|
| 64:02 | Okay. Um Anything else? Remember? Some can be used more |
|
| 64:12 | once? Transposition four and Okay, for all these for all these there's |
|
| 64:31 | that can be used for all of . Yeah. Five 55 recombination can |
|
| 64:39 | a part of all of them. , so um many questions, |
|
| 64:45 | Any questions? Okay. Alright, we'll knock off early then. So |
|
| 64:53 | uh see you next week. So week is viruses. Guess what we'll |
|
| 65:01 | about next week? Everybody's favorite |
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