| 00:05 | Thank you so much. I Ok. No, listen. |
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| 00:29 | I, ok. No, Uh I know I really. |
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| 00:56 | folks. Um welcome. So uh for braving the uh elements and um |
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| 01:11 | , you know, obviously, um is a big town, right? |
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| 01:16 | parts people live in all various parts Houston. Um and some are gonna |
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| 01:23 | more affected by this rain than others . So, um um, but |
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| 01:28 | know, we still have class, got a couple of emails we have |
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| 01:30 | class. Yes, we're in Uh but you can all because |
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| 01:34 | I'm only, I only follow what A is, right? They have |
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| 01:37 | office of emergency blah, blah and post a notice saying classes canceled whatever |
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| 01:43 | that's, that's I follow suit. . So if you're ever wondering, |
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| 01:48 | , it's I got bad weather by . Do we have classes? Just |
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| 01:51 | there and, and I, I what they tell me to do. |
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| 01:55 | . So, um obviously if it's safe for you to drive, then |
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| 02:00 | if it says classes canceled or, it says does not say it, |
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| 02:04 | you're directly affected by it. You only do what's safe. So obviously |
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| 02:10 | come to class. Ok. Um , so we do need this rain |
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| 02:17 | . We've been in a severe drought three months. So anyway, um |
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| 02:25 | you. So, um, all . So remember tomorrow next, uh |
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| 02:32 | opens for exam two? Ok. uh be aware of that and so |
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| 02:39 | some are still going to the old site that's not where you're going, |
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| 02:43 | going to this CCS version, So, um um so just remember |
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| 02:50 | . OK. Um If you're not your, the course, it's probably |
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| 02:54 | you're not at the right site. . Uh Usual stuff, quiz. |
|
| 02:59 | , weekly quiz. Um Tomorrow, work Monday do. Uh and we'll |
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| 03:06 | the last chapter that's gonna be covered this next exam. Chapter six of |
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| 03:13 | . All right. So we'll get a little bit of that here in |
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| 03:16 | bit. Uh So let's um let finish up what we've got left here |
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| 03:24 | four and start with um usual OK. Uh Let's see what we |
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| 03:32 | here. We go. So, right. I, I also, |
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| 03:36 | also helps me reset my brain as . So, uh OK. So |
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| 03:40 | , right? So we are looking in uh in this chapter. Uh |
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| 03:51 | gonna end it with um a couple , I guess you call it |
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| 03:55 | growth phenomenon phenomena, uh biofilm formation endospore formation. OK. And |
|
| 04:02 | uh so before we get there right? So we looked at the |
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| 04:06 | so if you're gonna grow microbes, , you need to supply the usual |
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| 04:11 | like cho NPS and various forms depending the nutritional type, right? So |
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| 04:17 | much uh where it begins is with , you know, carbon source. |
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| 04:22 | type is it? So we already about hetro autotroph, right? And |
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| 04:26 | supplying the right, you know, in terms of uh energy electron |
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| 04:31 | And as I mentioned, you these can the these certainly the electron |
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| 04:36 | can uh even energy source can be of the same thing, right? |
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| 04:41 | , right? For a for us a hetro will and any other hetro |
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| 04:46 | can serve as both the electron source oxidizing it as an energy source. |
|
| 04:51 | , you know, some of these are gonna be it's not just like |
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| 04:54 | source for each mo block, The nutrient can serve multiple roles. |
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| 05:01 | So you combine these different forms into medium, right? So we looked |
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| 05:05 | complex medium defined medium, OK. enrichment culture, fastidious bacteria. |
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| 05:12 | Remember these types have a lot of requirements, they can't do a lot |
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| 05:17 | their own kind of metabolism. So have to feed them lots of |
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| 05:21 | Um That's the nature of a fastidious . OK. Uh We also, |
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| 05:27 | think I didn't mention it here, we looked at, I think selective |
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| 05:29 | differential media. Um So there's there's for different purposes, you can use |
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| 05:34 | for different things to see if there's differences between cell types and maybe you |
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| 05:40 | to exclude certain types. So, know, you can, you can |
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| 05:43 | your medium for whatever kind of purpose want usually. OK. And then |
|
| 05:49 | we went into dynamics of growth, ? So we looked at a couple |
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| 05:53 | um of uh growth problems and there'll a couple, a couple of these |
|
| 05:59 | the test. So remember that you be allowed to have a calculator, |
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| 06:04 | type, any type in there uh do the problems. Um Then uh |
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| 06:10 | the other thing if um I forgot check um cannabis, but I did |
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| 06:15 | you I had some practice problems on . I can't remember if I did |
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| 06:19 | not. So I'll check and if they're not there, I'll put |
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| 06:22 | up. So if you have and all worked out, written out. |
|
| 06:25 | if you, if you having problems it, look at that. Uh |
|
| 06:28 | certainly you can contact me, if you need help. Um |
|
| 06:33 | of course, in, in monitoring , right? So you want to |
|
| 06:37 | um you know, getting this actual numbers, cell growth rates is um |
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| 06:43 | important. Certainly, if you're trying maximize cell growth, you wanna |
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| 06:47 | OK, what's, what rate does thing grow at all? Right? |
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| 06:51 | can I improve it? And so will give you actual quantitative data to |
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| 06:55 | that. Um And then we I think with a batch growth, |
|
| 07:02 | . So uh so remember, batch is basically you are making a |
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| 07:07 | you put it in your little flask vessel, whatever you use. And |
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| 07:11 | um you inoculate and basically you close . Although um unless it's an |
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| 07:18 | we are going it kind of have to air, right? So we're |
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| 07:23 | uh stir it, shake it up allow it to grow, right? |
|
| 07:27 | the only time we're going back in is to take a sample to measure |
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| 07:31 | . How many cells have I got this point? So we do that |
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| 07:34 | we're just basically tracking it throughout the life of the cell of the |
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| 07:39 | OK. Birth to death. And when you do that, you |
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| 07:43 | what's called the batch growth curve, ? So the stages are gonna be |
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| 07:48 | same for whatever microbe you're growing. just that the the uh durations the |
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| 07:55 | the lac face may be shorter or . The exponential growth may be very |
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| 08:03 | , maybe it's not so fast, it's more slower. Uh it's at |
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| 08:06 | rate, right? Stationary phase may short or long depends uh that |
|
| 08:12 | Of course, we are growth is declining. So they're dying at an |
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| 08:18 | rate. So all four stages occur how long, how short, how |
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| 08:25 | of a slope we have will vary on a number of factors. The |
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| 08:29 | type media you're using et cetera. . So um all right, |
|
| 08:37 | that's a brief recap. Any OK. So let's um look at |
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| 08:46 | , in fact. So, um is going beyond bad growth. |
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| 08:53 | And that would definitely be of interest you if your goal was to really |
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| 08:59 | cell growth. OK. For various , typically it's for in a, |
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| 09:05 | a industrial commercial context. Typically it's of an enzyme, a protein uh |
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| 09:13 | you want to commercialize. Uh it be the cell itself is the |
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| 09:17 | So you may wanna just, and you're doing things on an industrial |
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| 09:20 | eating lots of cells, OK. , um so if you're gonna do |
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| 09:27 | , you're gonna have to beef up medium, so to speak. |
|
| 09:32 | Add more stuff to make them keep , right? Because remember what |
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| 09:36 | the number one factor that influences growth carbon source, you'd add more carbon |
|
| 09:42 | you want to get more cells. ? And if you really get lots |
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| 09:46 | growth, then you may, you in addition, need to add nitrogen |
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| 09:50 | how, how many cells you're But you've become carbon limited, much |
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| 09:55 | than you do become nitrogen limited. ? But anyway, those are things |
|
| 10:00 | can, you can manipulate. And the fed batch growth, you simply |
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| 10:03 | taking that same vessel, right? you, you started with, you |
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| 10:08 | it and then at some time you add more stuff and the thing |
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| 10:13 | add is typically carbon and more right? And then it'll take off |
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| 10:17 | . OK. That's why you see curve here. We added, we |
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| 10:21 | um somewhere in this range we added fed feed, OK? Feed C |
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| 10:33 | the cells take off, right. you can time this, you |
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| 10:35 | you can do get an initial, an initial uh batch growth curve and |
|
| 10:40 | go OK. Well, if I it like to maybe right here, |
|
| 10:49 | have to take off very quickly right? If you wait, if |
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| 10:53 | wait till you're in stationary phase, may have to wait a while for |
|
| 10:56 | to kick in again. All So that those, those kind of |
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| 10:58 | can influence how fast you get But it will, you're probably more |
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| 11:02 | , you're gonna get more cells. ? And um if you're just doing |
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| 11:07 | in a vessel like this, a flask, right? There's, there's |
|
| 11:12 | . You can't keep doing this forever you could feed more than one |
|
| 11:16 | You can feed once, twice, times, but there's gonna be a |
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| 11:20 | . And so, you know, product builded up ph changes occur. |
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| 11:24 | so it just kind of craps so to speak. Ok. |
|
| 11:29 | but you do get a lot of . OK. So, um so |
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| 11:34 | other way to control it is in bio react, OK. Uh And |
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| 11:38 | could, and I've done this, but it's a pain in the butt |
|
| 11:43 | bacteria don't uh follow your time You have to follow their time |
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| 11:49 | right? So they, they wanna fed at two in the morning, |
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| 11:51 | gotta be there to feed them, ? So, um but you can |
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| 11:56 | a ph indicator into your medium and . It turns kind of yellowish, |
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| 12:02 | , reddish. OK. And so can both feed carbon and then look |
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| 12:07 | the flask and say, oh, it becoming acidic? Is it becoming |
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| 12:09 | basic? And they had acid the flask accordingly? And that |
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| 12:15 | that will work. But again, a pain in the butt because you |
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| 12:17 | to keep looking at it and making changes. So um manipulations rather. |
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| 12:23 | use a, use a bio, might uh computer controlled will do everything |
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| 12:28 | you, right? And you don't to get out of bed at night |
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| 12:31 | go feed him. Ok. So is just such a reactor. Um |
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| 12:36 | vessel. Yeah. Well, you all the uh the pumps here on |
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| 12:44 | side, right? So you can in um as in base, you |
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| 12:49 | your set points, uh add, um base if we get um below |
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| 12:59 | or something like that at, at if we get above uh 7.5 or |
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| 13:04 | . And so um it'll maintain that and uh then you can also |
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| 13:10 | do some other manipulations, right? can feed, automatically feed at a |
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| 13:14 | rate. So um this will cause high cell densities to occur. |
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| 13:20 | And, um, the other of course, these are temperature |
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| 13:23 | right. So, you, you a lot of cell growth thermodynamics, |
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| 13:26 | ? You're gonna give off a lot heat. So these things have |
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| 13:29 | our water jacket and water going around to, to cool it down or |
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| 13:34 | temperature rather. Um, ok. , you know, if it's, |
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| 13:39 | you, um, so you might , OK, if I wanna get |
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| 13:43 | of cells and I, and I do this by feeding, worry about |
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| 13:56 | . Well, if you do you'll find that um if you ever |
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| 14:04 | everything up front, it doesn't doesn't even get going. But why |
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| 14:10 | that be, why would it not growing? Ok. Anybody, you |
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| 14:16 | everything up front and now it's, it's not growing or what this thing |
|
| 14:21 | go to like 100 0 DS. , what's stopping it from growing that |
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| 14:28 | the cell in the liquid? Now just been adding all these nutrients and |
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| 14:32 | , but you're not growing. Why you, why are you not |
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| 14:36 | What's around you? Lots of, the word for molecules in a |
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| 14:44 | Solutes, solute concentration is very right? So remember that osmolarity, |
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| 14:51 | ? So if it's too, too solutes, right? The whole hypertonic |
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| 14:55 | is happening, right? So maybe comes so many solutes now that the |
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| 15:00 | it it's uh inhibiting growth because the is having to fight water loss to |
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| 15:06 | surroundings. Right. And so now goes ok. Oh, I'm not |
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| 15:09 | grow. Right. I can't It's just too many solutes. So |
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| 15:12 | what you have to feed. Uh With a batch feed or feed |
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| 15:17 | a regular intervals if you can in bio reactor, which I um if |
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| 15:22 | , and this is another thing that happen if an aero aerobic bacterium run |
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| 15:27 | liquid culture is adequately fed throughout. ? How you feed it so very |
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| 15:32 | ? What uh can limit growth unless can control this somehow manipulate this. |
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| 15:38 | it gonna run out of very Oxygen? Exactly. So um and |
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| 15:47 | can happen rather quickly. And so for I can remember, remember the |
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| 15:52 | , right? Glucose plus 0 right? If you co2 and water |
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| 15:57 | energy, right? So it's consuming . Obviously, you get a |
|
| 16:01 | right? Remember the uh the bod ? In a wastewater treatment plant, |
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| 16:07 | ? A lot of bod it's gonna the reification effect, right? Uh |
|
| 16:12 | all these matter, suck out right? So um so what you |
|
| 16:18 | do is I'm just showing you this I'm not, you're not gonna see |
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| 16:23 | bi record diagram on a test. is just for those of you who |
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| 16:27 | be interested in this ie biotech you may be running one of these |
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| 16:32 | one day. OK? Um So you do is right? Air So |
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| 16:39 | contraption here coupled with this, Uh What, what's called ad O |
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| 16:47 | , right? So the bod you can use it dissolves oxygen probe |
|
| 16:51 | measure 02 going away. It's the thing, just put it into the |
|
| 16:55 | . OK. So you can monitor . And so as 02 goes |
|
| 17:01 | what can you do? Well, up, speed up the storing, |
|
| 17:06 | ? That's what the uh that's what uh right here. Does this impeller |
|
| 17:11 | call it, right? This apparatus begin to spin more quickly, |
|
| 17:15 | And this, this is all you , all you can control all this |
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| 17:18 | , you just program to go. ? When dissolved oxygen gets down to |
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| 17:22 | right there, increased speed of impeller increased amount of air coming in. |
|
| 17:31 | . So that happens as well. ? And you this thing called a |
|
| 17:37 | , OK? And don't worry about . OK? So I'm not gonna |
|
| 17:41 | is not gonna be in the right? So, but uh I |
|
| 17:45 | , you know off chance you may that term. We go. What's |
|
| 17:49 | ? Your boss will be impressed that know it, right? So, |
|
| 17:52 | anyway, so sparger is basically that that forces air into tiny holes. |
|
| 18:01 | ? Because tiny gas bubbles are better what? Than big gas bubbles solubilized |
|
| 18:09 | the liquid, right? So small want small tiny bubbles that, |
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| 18:13 | that better is solubilized liquid. So plus getting more air in to a |
|
| 18:19 | and then spinning it real fast. helps both. All that helps to |
|
| 18:24 | the gas very quickly into the OK? And then the cells can |
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| 18:28 | it up right and begin to So anyway, so like I |
|
| 18:32 | you got ph Control, as you here, nutrient input here. So |
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| 18:37 | computer controlled, you can get super cell densities. OK? And then |
|
| 18:43 | if it's a industrial scale for so it's not like something, this |
|
| 18:49 | maybe like five liter size or something 10 liter. Uh it can be |
|
| 18:53 | 500 liter tank or 1000 liter OK? And what happens there is |
|
| 19:00 | it's when you're ready to harvest the , you would typically um take a |
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| 19:05 | out, put it in uh bottles you put it in a centrifuge, |
|
| 19:10 | ? And these all the cells will it out at the bottom of the |
|
| 19:14 | and you pour off the liquid, ? So an industrial scale, these |
|
| 19:19 | can be quite large. And so happens is you, you throw a |
|
| 19:25 | and liquid comes out, OK? the liquid comes into liquid being the |
|
| 19:32 | , right? It goes to think of it as an automated centrifuge |
|
| 19:37 | continuously runs and goes right into the and it spins it automatically. So |
|
| 19:43 | a fancy setup. I've, I've that before. And so it kind |
|
| 19:46 | just basically centrifuges as it comes in you get this big thick, thick |
|
| 19:51 | of paste, which is just basically of cells. OK? So um |
|
| 19:55 | you can combine this, you may this, this might be the upstream |
|
| 20:00 | , right? Where's my uh bia ? Is he here here? |
|
| 20:06 | So this is the upstream process. else can you do with that stuff |
|
| 20:12 | come out, right. That's your processing. You gone over that yet |
|
| 20:16 | class. OK? That's coming. . So, downstream processing. |
|
| 20:23 | so if you wanted to, you , do maybe you have to do |
|
| 20:26 | to it, right? Maybe you to um uh concentrate it. Maybe |
|
| 20:29 | have to take, maybe you have take some molecules out of it or |
|
| 20:32 | . So you can go downstream That kind of goes into the |
|
| 20:35 | right? They do their thing. you know, maybe they have |
|
| 20:39 | a filtration apparatus or something to kind filter stuff out or whatever the the |
|
| 20:43 | is, maybe you have to take cells and you wanna lice them and |
|
| 20:47 | you wanna get the DNA at them something, right? You can, |
|
| 20:51 | can then feed into a process where happens. So this is where if |
|
| 20:56 | the person running the bio reactor, is where you work with engineers and |
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| 21:00 | those kind of things downstream processing. you kind of work together to make |
|
| 21:04 | all work. OK? Anyway, more information than you wanted to |
|
| 21:09 | None of which will be, will tested on. So, don't worry |
|
| 21:12 | , oh, you're gonna see spar you're gonna see, you know, |
|
| 21:15 | reactor on a test. But, , anyway, so I put this |
|
| 21:20 | in here. All right. So is a way you can actually, |
|
| 21:25 | you're, if you're limited, just a flask to grow stuff, you |
|
| 21:28 | actually manipulate that. Right. So see, you're probably used to seeing |
|
| 21:33 | a regular flat bottom Eyre flask, ? So you see how this uh |
|
| 21:38 | thing has little um indentations in specially made for, for growing |
|
| 21:45 | right? And what that does is you're way too, to maximize air |
|
| 21:51 | in there is to shake it, ? You shake it and if you |
|
| 21:56 | it with these little indentations, it more turbulence. So you can actually |
|
| 21:59 | , you can compare growth in a bottom, someone like this, you |
|
| 22:03 | get a lot better growth with these you get more air turbulence and mixing |
|
| 22:06 | stuff. OK. So, um again, it's, you know, |
|
| 22:11 | aerobic types, it's, and you're into high density, it's, it's |
|
| 22:15 | , they rapidly get low on So you try to do what you |
|
| 22:19 | to maximize that. OK. Um questions. Uh Right. So now |
|
| 22:29 | last two things we're gonna talk about in terms of four chapter four. |
|
| 22:33 | this is typically there's gonna be two here back to back. So let |
|
| 22:38 | get that going. So this is a stress driven phenomenon initiated by a |
|
| 22:46 | of nutrients or other type of Ok. Could be, could be |
|
| 22:51 | temp, maybe Ph. Ok. like to name a few. |
|
| 23:01 | Oh, yes. Hm. Here on 1918, let's see. |
|
| 23:38 | going to predict. Let's see. got 209. I'll say 220 correct |
|
| 23:45 | . I'm sorry. 2 20. on baby. 01 47. |
|
| 23:52 | Not close. All right. 1 . Yes. In those four |
|
| 23:55 | OK. Um Let's look at the one real quick. OK. So |
|
| 24:04 | one, so a surface and the to attach your absolute requirements for. |
|
| 24:15 | see, let me speed this up little bit. Another 30 seconds. |
|
| 24:22 | . Um I'll say 200 correct answers time. 200. Mhm. You |
|
| 24:39 | do 10. Hm. OK. I say uh 200. Let's see |
|
| 24:50 | close. 02 60. Look at . OK. All right. Uh |
|
| 24:57 | , what, what was it? didn't see what letter everybody picked. |
|
| 25:00 | . See correct biofilm formation. Uh So first we'll talk about biofilm |
|
| 25:07 | here again. All right. So biofilm formation. Um OK. |
|
| 25:17 | number one, it's not a random together of microbe. OK? It's |
|
| 25:26 | uh orchestrated process. It's a gene process. Um It is, it |
|
| 25:35 | as it, as that question has , uh it's all about a |
|
| 25:39 | It's all about a surface, attaching a surface and then growing like |
|
| 25:44 | basically. Ok. So it is species specific phenomenon. Ok. But |
|
| 25:52 | but of course these things get large it can trap other things can get |
|
| 25:57 | in it. Ok. But um they're made by, you know, |
|
| 26:02 | species can either make it or they . So it, it's, |
|
| 26:06 | it's not just a random process. . So what is common to all |
|
| 26:10 | them is of course, you, begin with a little bit of, |
|
| 26:14 | attachment of a few cells that then if the environment is favorable, it |
|
| 26:25 | begin to initiate uh differentiate to a um by making the attachment more permanent |
|
| 26:33 | you will. OK. Um And of course, growth increases. |
|
| 26:39 | And then it keeps going. And now basically these three pitches are growth |
|
| 26:44 | , less than two dimensions on the , but then quickly becomes more goes |
|
| 26:50 | , you know, all three right? It becomes what they call |
|
| 26:54 | biofilm tower, right? So obviously a lots lots of cells there. |
|
| 27:00 | . So, uh you know, terms of, and, and these |
|
| 27:03 | found really they're prevalent everywhere, in um bodies of water in um |
|
| 27:12 | environments. Um And um you basically anywhere where there can be a |
|
| 27:18 | , right? And water, the , in fact, you can form |
|
| 27:22 | of growth, right? Um Obviously uh terrestrial environment, soil is the |
|
| 27:29 | , right. Um, very you know, industrially in pipes and |
|
| 27:33 | pipes and shower curtain, um, teeth, right. Plaque. These |
|
| 27:39 | all biofilms, uh medically important Uh uh any sort of think of |
|
| 27:46 | are medical devices? They, they a surface, right? A |
|
| 27:49 | a breathing tube, ventilation tube, uh different types of body part |
|
| 27:56 | right, hips, knees, uh cetera. These all can provide surfaces |
|
| 28:00 | so where you can get a biofilm is, is when the person handling |
|
| 28:06 | device uh doesn't handle it. Right. Maybe they're not using proper |
|
| 28:10 | pe and they contaminate with their hands this these things come sterility, packaged |
|
| 28:17 | when they're not handled properly, then can introduce a biofilm forming pathogen. |
|
| 28:22 | ? Just like this catheter here. And so staph infection results and there |
|
| 28:29 | staff types that can form biofilm. they do and the nature of BioFoam |
|
| 28:34 | lots of growth and um a very film, OK. Forms that can |
|
| 28:43 | Impenetrable to a degree by antibiotics. . And so uh biofilm infection takes |
|
| 28:50 | long time to really um cure it you will. Ok. Long, |
|
| 28:56 | , long uh period of antibiotic Ok. So very um problematic certainly |
|
| 29:05 | hospital settings. Ok. So let's at the process. Ok. So |
|
| 29:16 | and it's again some more examples and the uh the sugar snake here uh |
|
| 29:22 | was experienced that one of the uh I had, was you produce microbial |
|
| 29:29 | for like, restaurants and things to, um, either help with |
|
| 29:34 | grease traps or, um, this , this, this, these things |
|
| 29:40 | , uh, in the, in restaurants, convenience. So wherever |
|
| 29:43 | fill up your soda, right. one of those thingies, uh, |
|
| 29:48 | . Ok. And so there's all of tubing, right? That goes |
|
| 29:51 | like a, a syrup, syrupy in co2, blah, blah, |
|
| 29:56 | . Right. And so under the conditions, those pipes can, can |
|
| 30:02 | with a biofilm and uh produce like odors and things. And uh and |
|
| 30:10 | uh basically a biofilm we used to those things sugar snakes for some |
|
| 30:13 | somebody coined that term but pretty OK. And so, OK. |
|
| 30:18 | how does this process happen? Well, here are the five |
|
| 30:23 | OK. And again, this is coordinated through chemical signals, uh genes |
|
| 30:29 | turned on to initiate each process. so initiation attachment, maturation, maintenance |
|
| 30:36 | dissolution where kind of parts of it come off and then to kind of |
|
| 30:41 | bio elsewhere. OK. So we what are called planktonic cells. Uh |
|
| 30:48 | they call them swimmers and the opposite are called stickers, they stick to |
|
| 30:54 | surface. And so the planktonic cells kind of the free swimming, free |
|
| 30:58 | types, right? That are seeking land on the surface. OK. |
|
| 31:04 | then after that would be the so they become stickers through the through |
|
| 31:10 | formation of slash pia. OK. what you need to stick to something |
|
| 31:17 | maturation uh is basically the growing of . OK. So you have, |
|
| 31:22 | a constant for our biofilms is this opposite formation, which can also contain |
|
| 31:28 | some proteins in there. It's kind the glue that holds it all |
|
| 31:33 | OK. Then maintenance is basically just , you know, the, the |
|
| 31:39 | growth of it, the um um of it, ok. Uh The |
|
| 31:44 | maintain, maintenance of it. And in the process, of course, |
|
| 31:49 | grows and uh but it can um know, if you imagine sustaining a |
|
| 31:56 | with the millions and millions of souls , you're gonna have to have |
|
| 32:00 | a steady supply of nutrients to keep thing going, ok? And that's |
|
| 32:05 | often why you see it in a , right? Because they typically have |
|
| 32:07 | constant flow going through it, right nutrients. And so they can sustain |
|
| 32:12 | BioFoam for a long time, But you know, but you're also |
|
| 32:16 | see differences, right? BioFoam gets big and thick, you'll have little |
|
| 32:22 | environments in there where the cells will slightly different in terms of, you |
|
| 32:27 | , some may be getting more nutrients the outside of biofilm than those on |
|
| 32:31 | inside, right? So they can some metabolic di the metabolic differences within |
|
| 32:37 | biofilm. And so, um and some, some of those that become |
|
| 32:43 | , maybe you kind of break off then go elsewhere to form a biofilm |
|
| 32:46 | in a different location. So it's the life life of a of a |
|
| 32:52 | . OK. And so here just of shows you that process. So |
|
| 32:56 | qum sensing phenomenon we see in a of two or three examples this |
|
| 33:04 | this is one another one we'll see the context of um transformation in the |
|
| 33:09 | next unit transformation is cells that take DNA from the environment. We also |
|
| 33:15 | that as a quorum quorum sensing So, and what it is, |
|
| 33:19 | all about how many cell numbers are , right? So if you're familiar |
|
| 33:24 | um what's it called parliamentarian rules, ? Yet there are enough people present |
|
| 33:30 | , to vote to and a And so the same thing here, |
|
| 33:34 | all kind of cell density driven. um so it begins by cells attaching |
|
| 33:43 | the surface. OK. Now, me say that the attachment at this |
|
| 33:49 | is is reversible, right? So can go one of two ways it |
|
| 33:53 | continue on or become reversible. And the attractions I did some more |
|
| 33:59 | into this than what your book There's actually like attractive forces. If |
|
| 34:05 | recall from chemistry, Vanderwal Forces, . Um Those kind of attractions can |
|
| 34:11 | of keep the cells there for a . If it's gonna be become a |
|
| 34:16 | , it's gonna have to be a permanent attachment. OK? And that's |
|
| 34:20 | they'll develop. Pill. I re , OK? For that purpose, |
|
| 34:25 | only to attach to the surface but to each other. OK. And |
|
| 34:31 | , but again, it's all mediated these chemical signals. OK. So |
|
| 34:35 | may get the formation initially of some colonies. OK? We call it |
|
| 34:41 | represent, you know, like tiny of cells here there, right? |
|
| 34:44 | a full blown colony. And um chemical signals then are set up. |
|
| 34:50 | if there's enough cells there, then produce enough signal and you reach a |
|
| 34:57 | . OK? And if you reach threshold, then you'll go into biofilm |
|
| 35:01 | . So it becomes a more permanent . And so that's kind of this |
|
| 35:06 | what signals uh that threshold kind of where OK. Now we develop to |
|
| 35:13 | of stick. OK? And then form the polysac exo polysaccharide there and |
|
| 35:19 | to form as well. OK? so again, you're turning on, |
|
| 35:23 | course, different genes to initiate these . OK? And um so the |
|
| 35:30 | Saar formation is kind of what holds together. You may have switching |
|
| 35:36 | OK. So pim that motion on surface pili extending and then retracting and |
|
| 35:42 | may have some kind of motion but you're gonna get growth in all |
|
| 35:47 | dimensions. OK? And now now you're in the obviously mature biofilm |
|
| 35:53 | . And but again, you can differences oops see differences here on the |
|
| 36:00 | of the biofilm versus the exterior. . And cell types may vary. |
|
| 36:05 | I've even read where the types on inside are not getting the same nutrients |
|
| 36:11 | the ones on the outside are So they'll actually send out signals that |
|
| 36:17 | tell the peripheral microbe bacteria to hey, slow down on your eating |
|
| 36:24 | that some of that fruit can trickle to us here in the inside. |
|
| 36:27 | they, they've actually documented that kind kind of shooting going on. |
|
| 36:31 | um it's a very interesting, it's also, you know, in the |
|
| 36:36 | of uh medically important biofilms, the of antibiotics, right? That's uh |
|
| 36:45 | if they're trying to, they're treating biofilm infection for the antibiotics can't get |
|
| 36:53 | very well either. Ok. So may see because you see differences |
|
| 36:59 | in, in metabolic types in, the biofilm, someone may have more |
|
| 37:04 | to more resistance than others. And can then be an issue as well |
|
| 37:09 | there is more resistant types then grow . And so now you got, |
|
| 37:12 | got that problem to deal with. . So that's been seen as |
|
| 37:16 | So, um so, you and it's thought that bios are really |
|
| 37:22 | throughout the environment uh in, in different forms. OK. So, |
|
| 37:27 | like I said, typically at some point, uh some members |
|
| 37:32 | are, are just not gonna be to handle the lack of nutrients, |
|
| 37:37 | which can happen just because the, amount of nutrients coming into the system |
|
| 37:42 | just lessened or whatever. And so will break off and go elsewhere to |
|
| 37:48 | more favorable environment. OK? To the whole thing. OK. So |
|
| 37:56 | let's see any questions about bio, . And they can grow these in |
|
| 38:02 | . I um I was looking at youtube videos and they, they grow |
|
| 38:06 | and um um and a little uh , micro, well, what they |
|
| 38:13 | a plastic dish that has a bunch little wells in it. And they |
|
| 38:16 | these little metal metal uh mesh, metal mesh things in, into |
|
| 38:24 | into the wells and they inoculate And then you see this film form |
|
| 38:28 | top of the metal rings, it's cool. So, um and then |
|
| 38:34 | of the organism that we use in used it this week for lab |
|
| 38:40 | That's one that one because I see grow weird in the um in the |
|
| 38:44 | tube and I'm growing it up and , it forms like this, |
|
| 38:47 | it actually forms a film on, the, on the glass right near |
|
| 38:50 | liquid air interface. So it's uh interesting. So um anyhow, uh |
|
| 38:57 | flip to the next one. So in this formation, um and |
|
| 39:04 | are so many things, look across whole um periodic periodic spores, |
|
| 39:16 | Fungal spores were aware of that um pollen, right? Uh protozoans form |
|
| 39:25 | like cysts. OK. Uh All are kind of dormant forms of the |
|
| 39:32 | . Ok. So they're viable. . Or they can remain viable for |
|
| 39:38 | some time. Uh, and much a plant seed, you just have |
|
| 39:43 | , you know, under favorable conditions grow germinate, we call it. |
|
| 39:48 | . So, you know, all forms probably have some kind of um |
|
| 39:52 | , at least they have kind of dormant forms if you will. |
|
| 39:56 | Now, and spores and the term is used um is used, you |
|
| 40:02 | , in different, for different types well, right? Fungal spores. |
|
| 40:05 | can have bacterial spores that aren't in spores as well. Um But the |
|
| 40:12 | itself, that, that particular one the most resistant form. Ok. |
|
| 40:18 | to radiation. Um, temperature uh ph extremes. It's, it's |
|
| 40:25 | we have to use an autoclave for stuff is to kill end those |
|
| 40:29 | Ok. And so they can remain as you can see for quite some |
|
| 40:36 | . And so, um I remember seen a number of times when uh |
|
| 40:41 | Egyptian, uh what do you call ? Right. The king cuts and |
|
| 40:45 | that stuff. They open those things , they've recovered in those bores uh |
|
| 40:49 | those and have revived them and those more like maybe 5 to 10,000 years |
|
| 40:56 | . Now, here we're talking you know, quarter of a million |
|
| 40:59 | old, 40 million years old. so the endos spores are what you |
|
| 41:05 | . So, here's uh they look this. OK. That's actually in |
|
| 41:09 | cell. It's in the process of a, in those four. Here's |
|
| 41:12 | free in those four right there. . Uh Here's more here, |
|
| 41:17 | So, quite obvious. OK. so, um so this represents, |
|
| 41:23 | course, a very resistant form that viable for a long time. |
|
| 41:30 | Um And so there's only two groups form these particular types. OK. |
|
| 41:36 | Clostridium and bacillus. And so in of pathogens, clostridium has a number |
|
| 41:43 | pathogens and lots of they're toxin So, botulism, tetanus, uh |
|
| 41:50 | gas gangrene, you see there and also a toxin producer. These are |
|
| 41:53 | clostridium. OK? And um the difference between the two groups is right |
|
| 41:59 | is their uh usage of oxygen and botulism later in the context of |
|
| 42:12 | But uh they're both soil organisms, microbes, that's where you find |
|
| 42:18 | So you all heard step on a nail, gotta get a tetanus |
|
| 42:21 | right? Because the nail is in ground dirt and you know, contaminated |
|
| 42:25 | those spores of plus and and you be able to get, you might |
|
| 42:29 | tetanus from that. So you have get a shot, right? So |
|
| 42:33 | any case, these are a defense against stress conditions, right? Run |
|
| 42:40 | of food or some other stress it induce in those four formation. |
|
| 42:46 | And so like biofilm formation, this also a genetic program to this |
|
| 42:53 | OK. And it takes quite a actually from start to finish um to |
|
| 42:58 | the complete tree in those four, hours. And um during that |
|
| 43:05 | I guess you'd say what's going on a compartmentalization is going on in the |
|
| 43:12 | as well as um a reduction in . Right? So it's water |
|
| 43:18 | whether it's high temp or low it's water that does the damage because |
|
| 43:23 | low temp, they form ice crystals can puncture the cell, at high |
|
| 43:28 | , the water boils and can be proteins and things. So if you |
|
| 43:33 | remember, life has 70% water, ? So if you can lower that |
|
| 43:37 | of water, that will help in of preservation. So that's, and |
|
| 43:42 | what you see happening as well. those four formation is a reduction in |
|
| 43:46 | water content. OK? So, so let's look at this process. |
|
| 43:54 | And so the cell types you right? So if you put it |
|
| 43:57 | those four form under the microscope and can just do a gram stain, |
|
| 44:02 | ? Um You'll see the different And so what we see here is |
|
| 44:07 | a vegetative cell. So the vegetative is kind of the the usual functional |
|
| 44:13 | of the cell, right? The that grows and divides the one that's |
|
| 44:16 | vegetative type. Um That's what you here. It has no endospore in |
|
| 44:21 | at all. OK? So um then you're going to see also vegetative |
|
| 44:26 | that are in the process of forming spor, right? So you see |
|
| 44:30 | forming in the middle of the OK? Then you can have just |
|
| 44:35 | one, these are, it's gone it, it's completed. Now you |
|
| 44:38 | a free endospore. So you see three types, of course, the |
|
| 44:42 | proportions of the three types you see give you an indication of how much |
|
| 44:49 | it's under, right? So if see a uh where it's mostly just |
|
| 44:52 | end those board and yeah, you know, it's, it's gone |
|
| 44:55 | some stress and it's uh carrying the out. But if it's all strictly |
|
| 45:01 | cells, then it's probably nice and . OK. So um and so |
|
| 45:06 | , you can go from uh and those four back to vegetative growth under |
|
| 45:11 | right conditions. That's, that's the process. OK. And so uh |
|
| 45:15 | , I just threw this in just kind of give you the whole picture |
|
| 45:19 | , but I'm not gonna test you the different types. OK. But |
|
| 45:24 | can um use it as a way identify species among these endos four forms |
|
| 45:30 | the, the spor location where it or, or in the process, |
|
| 45:36 | swell the cell, some do some . So you see here uh swollen |
|
| 45:43 | and here uh non swollen over And the terminal sub terminal is the |
|
| 45:49 | terminal at one end, central in middle, sub terminal in between those |
|
| 45:54 | . So, and it can be , a species specific specific thing how |
|
| 45:59 | looks when it forms the endospore, are so, all right. So |
|
| 46:05 | begin the process with um since we're create a this entity called the endos |
|
| 46:14 | we're going to replicate the DNA replicate chromosome first. OK. Step |
|
| 46:20 | And then we're gonna kind of create elongated form what we call an axial |
|
| 46:28 | . OK. So it's basically just chromosome, the two copies of the |
|
| 46:31 | , right? And then one goes its own compartment. OK. That's |
|
| 46:35 | where we get the compartmentalization occurring. the four bore is where the front |
|
| 46:41 | or on here, the left, little smaller one on the left |
|
| 46:45 | the force board that's gonna become the . OK? And so what's going |
|
| 46:51 | while that's happening is the mother OK? Is kind of directing the |
|
| 46:58 | . That's why you see the arrow kind of toward the force for |
|
| 47:02 | Those are like um the mother's cell is producing that transcription factors um |
|
| 47:11 | that are turning certain genes on in 44 chromosome. OK. And so |
|
| 47:17 | worry about it. Yeah, but factors are things that control expression of |
|
| 47:22 | , right? So there's specific ones turn on the those involved in in |
|
| 47:27 | four formation at different times, So it's kind of that's what the |
|
| 47:30 | cell is kind of coordinating that part the process. OK. So um |
|
| 47:37 | uh next stage, so the end then is forming from this force |
|
| 47:43 | So you see how the mother cell engulfing this, OK. Uh That |
|
| 47:48 | form basically a double membrane, And in here is where we're gonna |
|
| 47:55 | it in with um pepto ICA pep material will be filled in to that |
|
| 48:01 | . Uh It's gonna become the So the cortex is basically a thick |
|
| 48:04 | of pepto glycan. OK? And see that the mother cell DNA here |
|
| 48:10 | is, is degrading, it's gonna away, right? So that, |
|
| 48:12 | goes away. And now it's a blown development of, of the uh |
|
| 48:19 | . OK? And so, dili DP A and calcium, OK. |
|
| 48:25 | those are unique to this process. ? And so what they do, |
|
| 48:31 | DP A um kind of stabilizes the um protects it. OK? Um |
|
| 48:41 | the combination of DP A, that's DP A DP A, that's what |
|
| 48:51 | stuff. That's the abbreviation for um nic acid. So DP A calcium |
|
| 48:57 | form a complex OK? In, the cortex. OK. And that |
|
| 49:03 | to kind of bind up water, ? So that's just where you get |
|
| 49:07 | , the desiccation occurring. The the removal of some of the water uh |
|
| 49:12 | through that complex. OK. Um then uh exo per, don't worry |
|
| 49:19 | that. So anyway, we're forming mature endos four here which will then |
|
| 49:25 | the cell, right. So, rest of the cell deteriorates around it |
|
| 49:29 | you're left with a free spor and spor. Ok. And of |
|
| 49:33 | that can remain viable then for, you saw millions of years in some |
|
| 49:39 | . Ok. So, um, again, it's all initiated, |
|
| 49:44 | It's all kicked off by some kind a stress, right? Lack of |
|
| 49:49 | , you know, bombardment with Ph, changes, whatever. |
|
| 49:54 | That's what, that's what starts the process. OK. Um And what |
|
| 50:00 | ? Um, there's something else Oops. OK. Any questions about |
|
| 50:07 | SPS? OK. We're very right? We've all, there's all |
|
| 50:12 | types of spores, right? But put Endo in the front of it |
|
| 50:18 | kicks it up a notch, Because again, we literally use an |
|
| 50:22 | play to get rid of these right? Because if we didn't have |
|
| 50:25 | those sports, we would have to an auto, right? You, |
|
| 50:28 | with some other kind of uh method um very, very resistant. |
|
| 50:34 | Any questions for, forget about OK. All right. Um And |
|
| 50:41 | bacillus, um anthrax, anthrax is . So anthrax is, is, |
|
| 50:47 | uh, have you heard of the somebody getting uh anthrax spores in |
|
| 50:52 | in the, in the mail, ? That's you, you can form |
|
| 50:55 | things, right? So, um of course it germinates and you |
|
| 51:00 | you get an anthrax. OK. , all right. So we're gonna |
|
| 51:05 | the switch now. Um to chapter . Chapter six is viruses. |
|
| 51:13 | And so, um so this first is really just about, here's how |
|
| 51:19 | define a virus. There's a structure a virus, here's how we classify |
|
| 51:25 | . OK. Um The second part really all about how they replicate so |
|
| 51:32 | life cycles. OK. Um We'll into kind of the basics of viral |
|
| 51:40 | . Um But let's uh let me this thing up here. Let's look |
|
| 51:44 | this question first. OK. So of the following is false concerning |
|
| 51:55 | OK. Let's take a look. similar. Hm. OK. |
|
| 52:34 | OK. Let me pause here at . Uh There is a false answer |
|
| 52:40 | . OK. So you need to your, change your answer. Go |
|
| 52:45 | . Yes. Um OK. So , there is a false answer. |
|
| 52:57 | is. OK. Let's see. course. Right? It's B |
|
| 53:04 | So they're not Akea, they're not , they're not e caros, |
|
| 53:11 | To their own thing. All they're not cells, right? But |
|
| 53:18 | certainly there is probably everything on earth gets affected by some kind of a |
|
| 53:25 | . OK. Uh So let's go some of these. Um We'll elaborate |
|
| 53:32 | these uh points here as we go . So, um OK. Discovery |
|
| 53:38 | briefly here. Uh OK. So mosaic virus, um although they didn't |
|
| 53:47 | they couldn't see it back then as talking like turn of the century, |
|
| 53:50 | turn of the 20th century, um um and they found plants that had |
|
| 54:08 | uh disease that affected the leaves that very like splotchy colored and obviously uh |
|
| 54:14 | able to photosynthesize correctly. And you know, sick plants more or |
|
| 54:18 | , right? So they go. so, so, of course, |
|
| 54:21 | this time, germ theory was, known, we all we knew about |
|
| 54:25 | at this time. And so the inclination was OK, let's follow hoax |
|
| 54:31 | 1234. And we'll find out that some kind of a, a microbe |
|
| 54:36 | this disease, right? And so proceeded to take, you know, |
|
| 54:40 | experiment, take the disease leaves, them up. It's kind of a |
|
| 54:47 | paste or something. If you will resuspended in buffer and run it through |
|
| 54:54 | filter, right? They had filters could trap uh bacteria. OK? |
|
| 55:00 | when they did this, they OK, we'll trap them on the |
|
| 55:05 | , we'll scrape it off the put it on a healthy leaf and |
|
| 55:10 | leaf will then become diseased. they didn't see that, right. |
|
| 55:15 | somebody had the idea to say, , well, let's not mess with |
|
| 55:18 | stuff on the filter because clearly it's that that's causing a disease. It's |
|
| 55:23 | in that. Let's look at what through the filter, the liquid, |
|
| 55:27 | ? It passed through these small And then when they applied that to |
|
| 55:31 | leaves, boom, they got came with the disease. So clearly, |
|
| 55:36 | thought OK. This is something super , right? And they didn't have |
|
| 55:46 | obviously need electron microscope to see So that's um that was like 30 |
|
| 55:50 | 40 years later when they discovered So anyway, um so these super |
|
| 55:58 | nanometer scale entities, right? Um um occupy that shelf in life. |
|
| 56:08 | is, is it life, is not life? And so um we |
|
| 56:14 | about this previously, the um you could say they're alive when they're |
|
| 56:20 | the host, right? When they're a host, you can't really say |
|
| 56:23 | alive, they don't exhibit any properties a cell as well because we call |
|
| 56:28 | a sailor. OK. So um uh uh they require a host first |
|
| 56:36 | foremost, right to, to replicate . They um as mentioned, they |
|
| 56:40 | , they were probably across the board life, something has a virus that |
|
| 56:45 | them and in terms of the So we're talking about this kind of |
|
| 56:49 | the end of, of next But um the role of viruses in |
|
| 56:55 | environment be very important in, in really maintaining uh species diversity in the |
|
| 57:11 | in many ways. OK. And my, when I studied this |
|
| 57:17 | it was OK. Virus, I see nothing that viruses do |
|
| 57:20 | you know, cause disease, but actually do a very important role in |
|
| 57:23 | environment and we'll talk about that uh the end. But um anyway, |
|
| 57:28 | mama. So that, so like things, certainly like microbes, other |
|
| 57:33 | , they span different size ranges, ? So the tiniest ones, |
|
| 57:37 | the tobacco mosaic virus is actually on low end in terms of size. |
|
| 57:42 | is on the high end, uh uh a micron in size. |
|
| 57:47 | uh we'll mention that today. But time there's actually now viruses that are |
|
| 57:51 | than this called giant viruses that that are over a micron in |
|
| 57:56 | And so, um, so you extremes there as well. So |
|
| 58:03 | um, let's look at this question . OK. So what's the following |
|
| 58:12 | a to e could not be used a criterion uh to identify a |
|
| 58:20 | OK. What would not make sense identify a virus with this? |
|
| 58:29 | And like the previous question, it's f OK. Uh So there |
|
| 58:37 | there is one that fits OK. , sorry. OK. Oops. |
|
| 59:01 | . 8543 in case I any Good. Yes, it is. |
|
| 59:14 | can't give them glucose and hope they'll . Ok. Uh They don't really |
|
| 59:20 | a metabolism in that sense like they , they don't have glycolysis, they |
|
| 59:25 | have so aspiration. OK. So rely on the host for that. |
|
| 59:32 | . But certainly, um, an , you take acid type, et |
|
| 59:37 | , you could all use that to a virus. OK. So let's |
|
| 59:43 | at the definition again, we use cellular to describe viruses, right? |
|
| 59:49 | You don't have the property you're familiar the properties of a cell are |
|
| 59:53 | A cell can replicate on its A cell can uh take in a |
|
| 59:58 | sources, produce energy, right? uh synthesize proteins, et cetera. |
|
| 60:05 | all the things we know cells can , right? They can't do all |
|
| 60:08 | things. And so viruses for that require host. That's what we call |
|
| 60:13 | . Obligate. Obligate means they they must do this obligate intracellular |
|
| 60:19 | OK. So at the most any virus will have a coat protein |
|
| 60:28 | and a genome, all viruses have feature. OK. Um And in |
|
| 60:35 | you look ahead, so viro and are not viruses. OK? So |
|
| 60:44 | , they're the, they're each their thing, right? So, so |
|
| 60:47 | virus is 11 type, then there's viro, then there's a prion, |
|
| 60:53 | ? So don't, you don't, don't use those terms interchangeably, |
|
| 60:57 | So a virus is a virus prime a prion. Viro is a |
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| 61:00 | OK. So, um OK. the name we used to call the |
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| 61:05 | is a caption, right? So of multiple units. Um again, |
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| 61:12 | can't self replicate and we're gonna go a basic uh viral life cycle. |
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| 61:18 | note that as we go into next into specifics about viral life cycles, |
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| 61:23 | all kinds of variations that occur. . So, um so let's look |
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| 61:29 | this question, in fact, which the following is not necessarily a requirement |
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| 61:39 | replication of all all not doesn't apply all. All right. And, |
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| 61:47 | , ok, once again, don't that, I'm just gonna start leaving |
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| 61:54 | off. I don't like, but have to keep it in there because |
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| 61:58 | gonna see it on the test. once you get out of the, |
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| 62:02 | know, what I need to do make, make the correct answer sometimes |
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| 62:06 | that you don't get afraid of picking if you need to. Ok. |
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| 62:25 | . Yeah. Ok. Ok. gonna say 22 10 is gonna be |
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| 62:42 | correct correct number here. 210. ok. 1 40. Ok. |
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| 62:50 | , I'm bad at this. All . Um it is a, it's |
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| 62:55 | that's not a requirement for all. . Not a requirement for all. |
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| 63:00 | . Um D was the other Yeah. So um in terms of |
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| 63:08 | one, a number of people picked so it's that is gonna be because |
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| 63:18 | um ok, I now I can why you might pick that. All |
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| 63:25 | . So who picked DD as in ? See I think you may be |
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| 63:29 | as well. I I'm gonna see you know why you may be |
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| 63:32 | Anybody picked DD as in dog or if you did or 80 something did |
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| 63:37 | did? Ok. So why did pick D no RN A? |
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| 63:46 | So if it's RN A virus, would need to use the OXY. |
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| 63:49 | right. So that's why that's As well. So, um, |
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| 63:54 | if you, yeah, for for that reason, then, |
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| 63:57 | so not all, so A is . Right? And because not all |
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| 64:03 | have to do that many DNA viruses like HIV does, but not |
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| 64:08 | But, and then as he right, you can have an RN |
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| 64:12 | virus, right? If you have RN A virus, they would need |
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| 64:16 | use these, right? They can . Right. So both of those |
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| 64:20 | be correct. So the correct answer uh G, all right, both |
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| 64:28 | A and B. All right. , all right. OK. So |
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| 64:36 | all right, you know, obviously all get credit for that. So |
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| 64:39 | worry about it. All right. , but is that the reasoning? |
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| 64:43 | sense? OK. All right. uh let's look at this. So |
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| 64:49 | uh again, so what you're gonna here, you know, is |
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| 64:57 | Well, let's just go through All right. So this first step |
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| 65:00 | absolutely every virus has got to do . OK? And that's be able |
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| 65:06 | um recognize the host obviously, So this is all about what's on |
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| 65:11 | periphery, right? So viral surface , uh host cell surface proteins, |
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| 65:20 | , you know the things that are the surface, right? So recognition |
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| 65:23 | specific molecules you gotta have that if doesn't happen, then the virus is |
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| 65:28 | going to infect, right? And beyond that, then you have different |
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| 65:34 | , right? So uh different things needs from the host. Really depends |
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| 65:40 | the type of virus. It right. RN A virus, DNA |
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| 65:45 | . Ok. Um Even within DNA . So you need a DNA ply |
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| 65:52 | copy the genome. If you're a virus, you may have your |
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| 65:55 | you may use the hosts. An RN A virus wouldn't care, |
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| 65:59 | doesn't need that, but it would AAA plym. Uh Of course, |
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| 66:03 | need it for, for um copying genome if you're an RN A |
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| 66:08 | Uh But there's also different types of A plumb races because you need a |
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| 66:12 | to transcribe, right? Um Of , ribosomes, Trnas, nucleotides, |
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| 66:19 | come from the host, OK? But again, they don't have a |
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| 66:24 | , right? So they don't as I mentioned, Glyco or these |
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| 66:27 | of things, right? So they on the, the host. |
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| 66:31 | So, so what uh so of , step one is get inside the |
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| 66:36 | once if you're, if you're recognized the host get inside and there can |
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| 66:40 | variations here. It may be the thing comes in, maybe it's just |
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| 66:46 | genome comes in. So you see . OK? Um Then of |
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| 66:51 | making copies that's universal. All viruses do that, right? Um Because |
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| 66:56 | thing you remember here is this is coming in, all right, and |
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| 67:00 | coming out are multiple viral particles. ? So if that's the case, |
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| 67:06 | gotta make multiple copies of the genome they're each gonna be stuffed into |
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| 67:12 | the progeny viral particles, right? you've also then got to make uh |
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| 67:19 | some variations are maybe before it does it goes into the host chromosome, |
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| 67:25 | ? So the types that do um but even if it's going to |
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| 67:29 | then revert. So while it's in host chromosome, it's kind of just |
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| 67:32 | out as the cell divides, its divides, right? So, um |
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| 67:37 | it was gonna replicate itself, it's have to go back to making copies |
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| 67:43 | then doing forming this basically factory, the cell as a factory to make |
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| 67:49 | , right? Intracellular uh replication OK. And so that of |
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| 67:55 | involves transcribing, translating viral genes because wanna make the parts right? We |
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| 68:01 | to, we have to create this , right? Create these inside the |
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| 68:07 | now and multiples of them, So we have to make copies of |
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| 68:11 | , we have to make viral proteins assemble everything, right? And so |
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| 68:17 | and so the word I use the and virus interchangeably, right? Um |
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| 68:26 | think that's OK. A virologist may me upside the head, but I |
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| 68:32 | this in that mean the same thing me. All right. So don't |
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| 68:37 | not, there's no difference to OK. Um Anyway, so, |
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| 68:41 | this is what we're assembling and making viral particles, right? So you're |
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| 68:45 | have to need, that's why you to make copies of genome and new |
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| 68:48 | proteins. OK. So, and they exit, right? You go |
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| 68:53 | to infect more sense. OK. again, the basic cycle for any |
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| 68:59 | , but as I pointed out, gonna be variations here and there, |
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| 69:04 | the outcome is the same. Um OK. So viral infectivity relates |
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| 69:11 | what? Well, if you're gonna effective, you gotta be able to |
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| 69:17 | your host, right? So it relates to those proteins on the host |
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| 69:23 | or glycoprotein molecules on the host cell . So it's all about recognizing |
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| 69:29 | OK. So whether you um can that and like recognize the host, |
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| 69:36 | ? Uh when you get in these are viral particles being that have |
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| 69:40 | been made, right? But getting is the key, you have to |
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| 69:43 | able to recognize the host. which is what this is all |
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| 69:47 | And so host range. Uh so have host range, there's 22 |
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| 69:55 | Let me just put it, put all up here. OK? So |
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| 69:59 | range and what we call tropism, ? So these are two, two |
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| 70:04 | things we have this related but OK. And that, so the |
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| 70:11 | range is a, a particular viral and how many different hosts in in |
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| 70:19 | fact, the classic example is right, squirrels, dogs, |
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| 70:23 | humans, bats, et cetera can be infected by the rabies virus, |
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| 70:28 | ? So the broad host range, . Mumps measles HIV. Very |
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| 70:35 | Right? Humans are the only ones infected by these. Ok. |
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| 70:41 | tropism is within the single host. . So if we take the, |
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| 70:48 | rabies virus, which can have a host range, you can infect different |
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| 70:54 | animals. Now, just look at inside of a squirrel, for |
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| 70:59 | Right. What are the different tissue ? It can infect in that squirrel |
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| 71:05 | ? Ok. And, um, rabies virus it's, it's um it's |
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| 71:11 | cells, in fact, nerve Ok. And in fact, it's |
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| 71:15 | be the same, same tissue type all the different hosts in us. |
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| 71:20 | a, in a, in a , in a squirrel, it will |
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| 71:24 | be just nerve cells. Ok. So that's a very narrow tropism, |
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| 71:32 | narrow specific. So the point is range, host range. How many |
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| 71:37 | host tropism, how many different cell in a single host? Ok. |
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| 71:43 | so uh Ebola, so here's right? Specific for those receptors on |
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| 71:50 | uh respiratory tract. Ok. Um narrow, a broad uh tropism is |
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| 72:00 | like Ebola. Ebola can actually infect um epithelial cells. Um endothelial cells |
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| 72:08 | make up, make up blood vessels things. And so multiple cell |
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| 72:14 | that's why it's so deadly. If you have Ebola, it's a |
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| 72:19 | death because you have fluids coming out everywhere. Ok. So it is |
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| 72:25 | a 80 90% mortality rate. So, um no, again, |
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| 72:31 | , narrow, right? And but, but remember the difference between |
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| 72:35 | two things, right? Host range tropism, right? Multiple hosts and |
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| 72:40 | within a host. Ok. All . That's, that's good folks. |
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| 72:44 | we'll pick it up next week. weekend. Coming up. 76 |
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| 72:53 | Yeah. Be over after today, think. |
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