All right, let's get into it. So, now we have incentive to show up at the beginning of class and to stay to the end of class hopefully. All righty. Make sure that I am okay. Just want to make sure that I check who is online. You guys, like I said, can always join on Zoom. All right. So, we're going to talk about microbes today. What what is microbiology? What are microbes? So micologist study of microorganisms which are organisms that are just too small to be seen with the naked eye. We would be talking about parasitic worms. Those guys you can see them with the naked eye straight up the adults anyways but we still often diagnose them because they're so hidden within the body. A lot of times we diagnose them by their eggs and their larae which are still often microscopic. Okay. So they'll fall in this category. So we're going to talk about all the major groups of microorganisms and we're going to divide them into major groups as part of taxonomy. It's one of the wonder things I'm sure we're going to remember from like eighth grade science or whatever you guys remember the kingdom file and all that stuff. So we're going to learn about that at the end of the chapter. But anyways, um these are our basic groups of pathogens. Pathogen um which we're going to define here in a moment is anything that can cause a disease. Any microbe that is diseasecausing. But we have like parasitic worms. We have prozzoa which are always single cell. Parasitic worms are always multi- cell. Fungi which includes obviously molds and yeasts, proarots which is going to be our bacteria and our archa. Viruses and pions. Viruses and pions they are not made of cells. We'll talk about what a cell is in a moment. Um and a pryion actually is just a misfolded protein weirdly enough. So uh let's talk about bacteria and archa. are proariots or a carot. Um they're changing the terminology. So I am so sorry for you guys that you have to put up with that but that's how that goes. But a if you think something like being like um a symptomatic without symptoms, right? So a carot without cario what is that? The nucleus. Kario is nucleus. You ever heard of karaotyping? before we take like all the X's and line them up and determine like you know what your chromosome 23 looks like and how many you have of it whatever let's talk about your nucleus. So a carot means without a nucleus. The other term that interchanges with aarote is proariote. You can see that there changing to aotology. Um proariote means pro before. Okay. So they um existed at a time before nucleus even if this nuclei even existed. Okay. So that's why they are worded the way they are. U means true. So we have a true nucleus. We are ukarotes. Um if it has a nucleus, this is a membranebound structure. We'll talk about what a membrane is. There's a lot of stuff to learn in this course. We'll talk about what a membrane is. but it's a membrane bound structure that just contains all the genetic information for their organism. It's all a nucleus. Think of it as a Smithsonian institution, right? If you wanted to go look something up in the Smithsonian institution or in some other library, major library or something like that, typically those big important things that really contain all that important information, it's the only copy of it. Uh you're not taking that out of there, right? It's going to stay in there. You can go in and make a copy of the gene, the blueprint of, you know, that particular room that you want to build, that particular chair or whatever it is. Write down the info for building that one thing and take that out of the Smithsonian. But you're not going to take all with you every time you need to build something. That's how your nucleus works, too. Instant contains all the blueprints for everything in your entire body. Every single cell in your entire body has all of the information you every type of cell. the colors of your eyes, your hair color, everything in every single cell of your body. Now, the cells that are in your skin versus the cells that are in your iris that make the eye color that you have versus your liver cells, all those things are receiving signals to only express certain genes, which is what makes genetics in chapter six. That's thing, but that's all contained within your nucleus. That's what a nucleus It's a membrane bound organel just like how you have organs in your body like the liver or whatever. We have similar structures inside each of your cells. Organels like tiny organs membrane only ukarotes have those. So if it has a nucleus, it has organels. It doesn't have a nucleus a proarot. They don't have any membrane or they don't have mitochondria. They don't have any plasma reticulum or any of those other structures that you probably heard about don't have any of that. It's all everything just goes on in the inside of their cell cytoplasm. What's the main difference between these guys? Membrane bound organels or not. Okay. Photosynthetic microorganisms. More than 70% of the oxygen in our atmosphere comes from microbes, not plants. Most of our atmosphere that we breathe that we rely on for existence comes from microbes, not plants. So we're talking algae. Algae are not plants. They're protista. Kind of like our prozzoa are. Um like plankton and things like that. They fall into that protista. They're photosynthetic. They're green. That green layer on lakes and things like that. Um but those are the guys that changed our atmosphere. In fact, all evidence supports the idea that when Earth first existed, there was no oxygen in our atmosphere whatsoever. Life came to be, however you believe that happened. Life came to be somehow on the planet and that life made oxygen as a byproduct. Then life evolved to use that oxygen byproduct for it to bank and that's how we have oxygen on Earth. That's the idea of how that we have micro to banking that oxygen. that we today. So, it's pretty impressive the impact these microbes had over billions of years on the planet that we're treating so beautifully now today. All right. We also know microbes are so important for decomposition. I don't think I'm going to tell you guys that, right? Fungi and bacteria play a big part in that. What else can we use microbes for? Obviously, we use yeast for making bread and beer and wine and things like that. These guys ferment. We've heard the term before. We're going to learn about what fermentation is and how it works and how it operates for microbes, why they do it and that sort of stuff later on, but that's coming, right? We know we can use them for that. We also can use them for things like biotech. So, we can actually hijack the simplicity of a bacteria. They're so simple, they don't even have organels, right? So, we can actually take their simple makeup and hijack that. put in a human gene like a gene for insulin inside of a bacteria like E. coli and now force it to just crank out insulin non-stop. That's where diabetic insulin comes from and force bacteria to make human insulin. Very impressive. Makes insulin affordable and available for people who need it to survive. What did they do before bacteria? They took cow pancreases and made insulin from that. So before they even got smart enough to do that, what what would they do for people who had who have diabetes, they would die. So, science is you guys know because you're going to medicine. So, you got have an appreciation for that. But, um, we're going to talk about that uses that are obvious like that. We're also going to be talking about things like GMOs and how whether they're dangerous for you and how they're actually dangerous for you. Spoiler alert, if you eat a GMO, you can't get the genes into your genes. That's not how GMOs work. Okay? Literally not how that would mean if you could take GMO like let's say you take corn that has bacteria genes in it to help it resist any insects, right? Natural genes for insects. Um so you don't need pesticides, right? Eat that corn. Does that mean you can get that bacteria gene into your genes now and now your eat? No. Because that would mean that you just ate the regular corn. You could just eat the regular corn genes. Why would that gene be more like what? The DNA doesn't just hop around in the DNA like from plant to plant. Guess what? But we'll talk about that. We'll talk about what the real dangers are. The real dangers are if you put a pesticide gene into corn, the likelihood of it jumping into wild um plants could be a danger. And now you've got plants that are resistant to to pests and those pests, you know, needed to survive. Now we've ruined a whole ecosystem. That's the real problem with GMOs. Um anyways, pathogens. Pathogen is any microbe that can cause disease. Okay? So it's a contagious disease and caused by a microbe. That microbe is a pathogen. You can have pathogens that are just always pathogens like CO. CO is CO doesn't just exist naturally in your body. Sometimes CO flu always causes a flu. However, can you have staff be part of your normal biome? Yeah. Right. So, you can, but sometimes it causes disease, right? We'll get cellulitis. We'll get associated with it. Become resistant and come up. So sometimes we have pathogens that aren't always pathogens, right? So we call those opportunistic pathogens. I'll talk about all this stuff. We talk about disease. Is all disease caused by pathogens? No, obviously not. The number one leading causes of death in the United States just overall is going to be heart disease and cancer. Most of those aren't going to be caused by microbes. Can microbes cause cancer? Yes. If you're a woman, you probably know that's the whole point of a capacitor, right? To look for HPV that causes her. So for that too, but do remember disease is a deviation from health of perceive what you perceive to be health. If you're deviating from that, you got disease. If it's caused by a micro that's caused by a pathogen. All right. Uh generally speaking, our bacteria and our archa those are our aarotes. Remember those guys are smaller than ukarotes. This shouldn't be too surprising um when I'm telling you that they're simpler and that the ukarotes have to house all these freaking organels that are membrane bound. They need more space for that. So they're tend to be more complex. The more complex we are, the bigger we are. So not surprising there. Bacteria and archa. They are cells. They're membrane bound discrete living units. That's what a cell is. A cell is a membrane bound unit that is capable of reproducing itself and has all everything that it needs to another copy of itself. Now, your skin cells do that, right? You you have a a skin cell that can make an exact copy of itself through mitosis and make, you know, another skin cell, whatever. If I take that skin tone and I just stay inside it just to grow a whole new right [Music] organism for that single cell organisms make a copy of the cell and then that copy. That's the difference between single cell and multisell. So we know a cell is a membrane bound unit that can reproduce itself. So, why aren't viruses? Viruses can have a membrane. They don't always talk all viruses are in chapter 7, but they to reproduce. They absolutely 100% always need your cells machinery. They can't do it on their own. They're going to use the structures and the nutrients, all the proteins, the amino acids, and all ribosomes in your cell functions. We'll talk about what these structures are later, but they need all that. They steal it while they're in your cell. Build more viruses. They can't do it without being in your cell. So, are they alive on their own? I don't I don't know, right? And science is pretty they don't know. They don't have to find what's living, what's not. We know cells are living. We'll just leave that. Cells are living for sure. I'll leave it to your opinion on whether you think a virus is alive, but they definitely depend on the host cell. Pryion, like I've stated before, we'll talk about these in chapter seven, are just misfolded proteins. We'll talk about what that means later. All righty. Um, scientific method, you guys have almost certainly heard of this. I'm not going to go over this in super big detail. I'm not going to get big old questions on the test about this, but you should probably just be familiar with the fact that a hypothesis is your explanation for what you think is going on. You're going to do experiments to test that hypothesis. If you're right, hey, you're going to repeat it to make sure you are right. You might do it in different variations to help support it. If you're wrong, you're going to change it up, make a different guess, and then test that hypothesis. Right? That's the whole point of the science method. All right? A theory is just you've done this over and you've got made your hypothesis. You've supported it. You've done it a ton of times. Other people have done it a ton of times to support it. And now it seems like this seems to be the truth. But science is very very tentative at saying this is the absolute 100% always going to be this way because that's what a theory is. It's just saying like this is everything supports this that we have but we don't want to say that you can can't rule out other things. So it's their you know ca move if you will. All righty let's talk about some old guys. Um, Louis Pastor, you probably heard of the guy pasture. Um, and pasteurization. You probably heard of that, right? Your milk is usually pasteurized. Actually, if you're buying milk legally in the United States, it's pasteurized. So, um, this is who it's named after. So, Louisie Pasture was a scientist who he was hearing everybody talking about something called spontaneous generation as an explanation for why meat goes bad and why people get sick or whatever. And spontaneous generation basically said that life will come out on its own. Um, if you leave out a steak on this lovely bench here, this counter top, and just let it sit out and it starts to get, you know, gross and grow mold on it and bacteria, slimy goodness on it and maggots or whatever, that's just something that just happens over. Um, there's to us that just sounds wild because we've become so familiar with that concept of duh, there's microbes there that are growing like they're just you're giving them the opportunity to grow. that's happening. Um, but back then they didn't understand about that. They couldn't see it. He couldn't see it either, but he was pretty sure it was there. So, what he did was he took broth, just say any broth, but it doesn't matter. A liquid with nutrients in it. That's broth. They took a broth. He boiled it to sterilize it. And he left some broth, say open the tiniest little snake of air so that can They need to survive better. The one that boil that was sterile expos. What do you think happened? It grew, right? It grew nasty. The ones that had just a little snake of the air microbes could get in sterile. If it was spontaneous, it would have still be. So that's how he did elegant experiment. He just spontaneous. That's that. Now you guys know pasture stands for that. There's also some other old guys. I'm not going to test you about these guys on the first test, but it's nice to know kind of what they contributed. We'll talk about coke later on. Um, but Robert Ko came up with the idea of how to identify the cause of disease. Basically coke postulates. And then Holmes and Soloise, these guys came up with idea of maybe wash your hands between patients. Um, yeah. So, if we don't have a spontaneous generation isn't a thing, that means if uh my patient wasn't infected and then I cut them and now they're infected and that's the thing that happened in between the two things, maybe I transfer and so they suggested maybe watch because what happened was that doctors who were performing autopsy would go from bare handing the autopsy on and then going and delivering babies. babies were dying, women were dying and all this. Whereas the midwives who were delivering the babies were washing way more likely to survive by midwife and so they suggest maybe Washington. So that worked. Um then we have Joseph Listister. You heard of Lististerine? Yeah. Think of that whenever you hear that name. Okay. So Listister um who Lististerine is named after. He came up with the idea of taking carbolic acid which is phenol and sanitizing his operating theaters before he would perform surgeries. He'd also wash his hands and perform what we would consider kind of moderate introduction into aseptic technique or surgical asexis. So um he saw a significant decline in infection in his certification as a result of that. So Listister Listerine he's the one that decided to clean his his operating theaters. Pasture is associated with discovering the spontaneous generation was false. Okay, we already talked about this. I don't know why it's on here twice, right? Let's talk about naming and classifying these organisms. There's so many freaking microbes out there. You can probably name a bunch of them off your head without even having taken microbiology. Um, you might not know the full entire names for those guys, but I know most of you guys know staff. You probably heard of staff. You probably heard of ecoli. You probably heard of salmonella. And these things are just so like you know bacteria. you've heard of bacterians, not news to you. Um, but there's there's rules for how we name them. There's rules for how we write their names and um how we're classifying them so that we can help identify them. Putting them into these categories based on certain characteristics so that hey, this organism fermentss my my patient when I swab them and I isolated their organism, it turns out that it fermented glucose. That's something you can use to help identify the organism. That's pretty much what lab is doing is identifying organisms based on characteristics. The system we use to name our organisms is called binomial nomenclature. This is where we're getting eoli from. Right? So there is a first name and a first word and a second word. We'll say the first word comes from the genus name. It's like the group of them. They usually have similar characteristics in that group like stafalocus. You guys are going to learn what sacklo is. You're going to learn what caucus is in chapter four. Um, but that tells you stuff about the organism. And then we have some is named after a person and some name trait. I wish they were all just name traits because that would just make it so much easier than freaking name one random word like aia, but whatever that's science. So um, but the first word is the genus and the second word is called the specific FF and together that's the species name. Okay. So for E.oli, which is almost always abbreviated, we're so used to as E. coli. The E stands for Echerikia. Echerikia coli. Um, I'm never going to have you guys there's I say there's one project that we have which is our lab unknown project where I will have you write your organism's name out. I'm not going to sit there and be like write your organism's name and then I'm going to be like, "Oh, you got it wrong." I'm tell you what a freaking organism's name is and then when you put it into your report, you better spell it right. Okay. I'm better use that two name system the first one is lowerase and if you're typing it and then writing you underline that unknown report when you submit that at the very end is the only time I'm ever going to have access to that practice I will have a question on the test where I will say which one of the following courses is the appropriate way to write the So we'll have that other than that micro better not be confusing at the end of this course status and salmonella. Okay. Anyways, moving on. We have our very very familiar um kingdom file class order family genus species. It's one of those things if I don't spit it out like that all in one long thing um I don't remember it either. Okay. So, you'll have one question on the test of life. Uh if you if I give you a list of things, which one does order come after? You know, which one is in the correct order or a question similar to that test. Again, this is the last color when you have that on final out there. Okay, but I have to teach it to you. This is the time you'll have it on your unit or um so remember the order however you need to. It's like king filler came over for good spaghetti. That's one way you can remember it. Um or whatever acronym you want to use. Domain is the big one. We popped it on top. Domain is the only one that I need you to know the subsets that fall into domain. I'm not going to ask about the different kingdoms. There aren't that many kingdoms, but I'm not going to ask you about them. I am going to ask about domains. Three domains are we've already talked about ukaria, uh, bacteria and archa. We already talked about um, so you could even take, hey, there are cells. If you're a cell, you're either a ukareote or an a or pro, right? You have organels. If you're a ukarot, you automatically fall into domain ukarot. If you're an aarote, you're either a bacteria or an archote. So, we're already starting to divide these things up. 99.9% of our talk in microbiology is going to be about bacteria. Um, we'll talk about fungi and stuff, too. I mean, but like as far as like the procarots, I'm not going to really talk much about archa. So, here's how they're divided up. You can see here that actually archa this like way this relates to us but more related to us actually bacteria relate to it. You're looking at an archa under microscope. They're single cell. They're a carot. You look under the microscope, bacteria and archa look exactly the same, but they have way different molecular makeup. Okay. I have weird like hydrocarbon like non traditional makeup in their like cell membranes and things like they're weird. They're like weird. So, um but they have the same ribosomes that we do. They don't have the same bacteria. It's just like a weird mix matching. It's completely different. That's the point. We're not going to talk about it much. So, moving on to chapter three, which is our tools. We're going to talk about the five eyes. We're going to get into each of these. Inoculation, incubation, isolation, inspection, and identification. It's a good infographic kind of summarizing that we are studying. Inoculation is producing a culture. Ideally, your goal is to make a pure culture. Let's say you go to uh urgent care with a sore throat. Actually, like the week before classes started, I was having a sore throat and a cough. And so, I went to urgent care and um what are they going to do? They're going to swab your nose and your throat. They're going to run rapid COVID, rapid flu, and rapid strep, right? No surprise there. All of mine were negative. So, I mean, no biggie on me. Like, I was having I clearly had bronchitis. It was down in my throat and I was coughing yucky stuff up. So, it's like antibiotic. You'll probably get over it, right? We didn't need to know exactly what it was. We had an idea of what we could probably guess at what we thought it might be. And even you guys by the end of this semester, I hope probably be able to guess what we thought it might have been. But we don't need to know exactly what it was. Now, your patient comes in and they're blue. You're in the ER. They're blue. They can barely breathe. They're testing negative for those three things. Now, what? Right? You might want to know what that is. Number one, treat them better because now they're going to need more specific treatment. You can't just throw a monster at that one probably. Number two, um let's say you did throw a monster at it, but they didn't get better. Now what? Um number three, they have an immune system problem or they're older, they're pregnant. Their immune system is weaker for those things. Could be all sorts of things, but you might want to know what that organism is. This course is going to give you the information you would need to help figure that out. So that stuff might be obvious. So might not your patient, let's say your patient that's coming in blue in the face was also coughing up blood and was also homeless. Um probably tuberculosis. You might be like, "Well, not really that common." Well, actually a third of the world has tuberculosis. Onethird that's not an exaggeration. So uh probably more likely than you think it is, especially in the homeless population where they are living very close quarter to another and not getting appropriate healthcare. Actually had an outbreak of in schools a little while back, a couple years ago, the students, health people, more common than you probably think it is. So, there's easy quick tests for that, but you'd want to know what signs to look out for to reach for those tests, right? And how would you know if you didn't take microbiology? Um, well, the doctor will probably know, but it's going to make you a lot better of a healthcare provider if you can understand why you're doing what for your for your patients and so that when their family has questions, you're the one that's going to be there, right? Not the doctor. always a doctor around. So, I don't know if you guys ever been to a doctor or stayed in the hospital, but the doctor is like there like 1% of the time and the nurse is there always. So, you're going to be the ones there and it's going to help you be a better healthcare provider if you know what you are. That's the reason why that's why they ask you to take the class so that you understand what you're doing that on the pathogen side. That's my job. Um anyways, so you swab someone's throat. You they're blue in the face. you want to figure out what's going on with them. You might want to culture it so that you can start figuring out what it is. You put someone's uh a swab, a sterile swab on someone's throat and you put it onto sterile media that'll grow about anything. Do you think that the only thing that's going to grow in there? Do you think that your throat is sterile unless you're sick? Right. We know we have biome that bacteria are in our mouths all the time when you're healthy and your throat gut there's so many bacteria in there. We also that ecoli is part of your normal most people's normal diet normal ecoli. So how do you distinguish right? So when we create a culture taking a swab of someone's throat putting it onto that sterile media and growing it that's inoculation um taking that sterile media and putting that swab on it. That's the actual practice for legit. That's what inoculation means. That's what that term is. Now you created a culture by doing that. the stuff you're growing it on is the media. And these are all obvious things and we kind of understand the practice of it, but these are the terms that go along with it is what the point is. Something is sterile if it is free of all life forms. We're going to talk about the difference between sterile and like disinfection and sanitization and things like that later on in the course. There's a whole bunch of different kinds of media that we be working with. We're obviously going to learn this in practice in more detail in the lab, but things like liquid versus solid. Um, chemical composition and then what you're actually using the media for. We'll talk about composition in a moment, but for for what the media is used for, if you're just trying to grow up some stuff, general purpose. If you if your organism won't grow on basic normal use media and it needs some extra thing added to it, that media is called enriched. We're going to get into that. Selective versus differential. that's coming through. Reducing media is used for organisms that can't grow in oxygen. So there are microbes, some of them that live in your gut that if we expose them to oxygen, they would die or they turn into like a dormant form of themselves. One of the most popular, most friendly, most beloved of all these microbes is seiff. Seiff is an anorob. It cannot grow in the presence of oxygen. However, it turns into an endospor, which is very hardy, dormant form. Um, we'll learn about that in chapter four. That that thing is resistant to almost everything. And so, it's like once your patient has seated, it is way too easy to spread it from patient to patient. And so, even even when you're, you know, performing proper aseptic technique, the odds of spreading it, it's just so high that you just have no idea. If you haven't worked in a hospital, those of you who are going into nursing, you will have rotations to hospitals. if you don't want to stay in one, you're going to find out. So, you'll understand the smell and you'll understand the effects. It's not nice. Um, specimen transport. This just means we're keeping the organisms happy till we can get them to the lab where they're probably going to culture them because obviously you guys aren't culturing them as nurses. It's nice to know what's happening in the lab. Um, assay media is media that's specific for whatever assay they're doing. And then enumeration just means media that's used for counting. You might want to know like how many bacteria are in a blood culture for example. Gives you an idea of how infected your patient would be. We already talked about these. Semiolid just means that it's like got a solid aspect to it but it's not completely solid. I mean I don't know why I'm explaining that. You guys know what that word means. Um to make media solid we're basically taking essentially what is a nutrient broth and adding augur to it. Augur is a sugarbased compound from algae that gives a solidifying aspect to it. Then we have a surface that's solid that we can grow these guys on. And why is that important? Well, we're going to talk about that. Um, defined media is something where we know the exact chemical composition. You put in 0.5% sodium chloride and blah blah blah blah blah exact composition of chemicals in there. You know exactly what's in there. It's useful for research because now you can say, well, all of our studies were done with these exact chemical components. We know exactly what's in there. Now that might seem like why isn't that used all the time? Because actually most of the time we're using complex media. So this is things like blood augur. So here we would have like 5% cheap blood added in like nutrient augur. A lot of pathogenic organisms need like living cell nutrients available to them that we don't have in just regular media. So we're adding something to it. But does every single sheep blood have the exact same composition as every single sheep blood? Well, we wish we could control that. But no, it's literally just sheep blood. So, um, that's where we're talking about complex. You don't know the exact chemical composition, but you know, it has sheep blood in it. That's the best you can do. So, all right. General general purpose. We talked about that general growth. So, here's what we come back to enrich. Enriched media is where you have media. We add something to the media that that organism needs to have provided to it because it can't make it for itself. Think about how you need vitamins in your diet. You have to eat a variety of foods. Be sure you're getting vitamin B12, um, vitamin C, and all these things. Your body cannot make those vitamins. You need it provided to you in your diet. And there might be amino acids that need to build your structural proteins and your cells that you have to get from your diet. You can't make them. Your cells aren't able to make it. For example, lysine. Anybody ever seen Jurassic Park question? people in Jurassic Park, right? You guys remember how they talk about the lysine contingency in Jurassic Park? Well, the the dinosaurs, they need lysine in their diet to build their cells. Um, and we and we have to provide we've made it so we have to provide that in their diet to them. So, uh, they can't make it themselves. And you know, um, what's his face? Jeff Goldblum is like, well, life will find a way. He eventually does, right? Well, as it turns out, all living organisms uh need lysine provided to them in their diet. You can't make it for yourself. So, you're getting your lysine that you need to build up your proteins with the amino acids, the essential amino acids, uh provided in your diet. So, anything that's like that in an organism's diet that must be provided in the diet, they can't make for themselves like vitamins and lysine. Um those are called growth factors and bacteria have things like that. And it's different. species to species like it would be from between us and like dogs. Maybe dogs can make some of their vitamins that we can't. So that's the idea. For example, bacteria can make folate. We have to have folate provided to us in our diets. Um they need it provided in their uh media. That's a growth factor. Organisms that have specific requirements like that are called fastidious. And the media that that acidious bacteria grow on that has the growth factor in it is called enriched. So those are the three terms that kind of go with each other. Okay, those will definitely be on the desk. Selective media. This is media that that selects for one organism and or group of organisms and doesn't allow birth for other ones. So it might have some sort of additive in it that is toxic to a group of organisms. We have media out there that has an ingredient in it that is toxic to gram negative and we'll talk about what gram positive gram negative mean there's toxic gram negative and so only gram positives can grow on it or vice versa. So um anytime it has an ingredient in it that prohibits growth of another group it's selective. So this is controlling what can grow. Differential media on the other hand doesn't control what can grow but what grows has an effect on the media. Usually it causes a color change. So if something can ferment it might you know you guys know how when you ferment things sometimes one of the products can be acid. So when you eat like yogurt or kombucha or sauerkraut or something has acid in it made from fermentation. So if it causes a pH change. So here we are talking about um you know if they have more acid than something pH change we have color indicators that'll change color for that. A lot of these are based on pH change. I'm going to be honest. Um, but it can be based on a whole ton of different metabolic products that can cause color changes. We'll talk about different tests and how those color changes come about and unfortunately for you the chemistry of how that works and everything um later on in the course, but now you know the difference between these two. Selective media, we are encouraging the growth of certain species and not others. We're selecting for differential media, you can see the difference between microbes and media by color. with metal. Can you have media that does both? Um, one example of differential media is blood augur. So, most things can grow on blood augur. We already talked about a little bit what it is. She blood added into augur. Something has something called a hemoly. This is an enzyme that breaks down red blood cells. So, it's called hemolysis. So, he bloodly breakdown. Blood cell breakdown. If something can grow on blood augur, it has a hemolytic aspect to it. It's automatic. Okay. As three characteristics, three traits I guess you could put it into that grows on blood offer. Beta, alpha or gammais. Gamma is just no homoysis. Don't ask me why they do that to us. Okay, but that's if it grows on it and you don't see any change in the media that's relative to homoysis, then it is gamma homoysis. Okay, so it's always one of the three if it grows. All right, alpha and beta. So alpha, you can think of it as the first step. Okay, we start having seeing breakdown, but it's not complete breakdown. The first step is we start seeing the breakdown. So you get a greenish tinge to the blood. But if you're completely breaking down the blood cells, that's beta. That's the next step. So again, actual clearing out of that area. You can see here in this area for this halo that's developed, this organism has completely broken down. So alpha is that first step. This brings partial breakdown. Beta total breakdown, total clearing through. If you're a patient streped throat and you put it on a blood plate and you saw that was clearing that's something you know the organism is a beta hemolizer here we have examples that screw on the plate we have streptocockus sanguin is actually pretty common normal that grows in your mouth um you want to isolate out compared to what is cause alpha not true all the Let's say that your patient there had this full line. Well, this guy happens to be strepto and that's there's a defining characteristic right there bacterialites already learning stuff. Um, so we have media that can be both. Like I said, examples would be manki augur or manitol. This is a picture of man salt auger man auger have little salt in it. Gram negative bacteria we'll talk about why what that mean but they hate salt. So they're not going to grow on this positives like they can grow here. We're already positive. We've already kicked out a brown negative. And now also we have aator. It starts out red. If it makes acid, it turns yellow. We're breaking down a sugar and fermenting it into acid. We're going to turn the media yellow. Turns out that very very common bacteria on your skin staff will epidermis almost everybody has grown on them right now. That guy will grow on that media but won't turn it yellow. But guess what will turn it yellow? Staff will call this orius. So our typical staff bad guy that guy will turn yellow. This is information now we can use in our diagnostic practices as well as for isolation. This is both selective because we selected with the salt, right? And differential because we might have a color change that'll tell us something about it. We'll learn all about that in the lab. So colony whenever you guys see all those plates growing we have all these little spots growing up on plates those are called colonies and one colony comes from one cell one cell that just multiplied up and piled up on itself that's useful because that means if I can swap your throat and put it down on a plate it's just a whole bunch of crap growing on it's all mish mashed all together if I spread it out enough and get those cells separated enough we can get discrete colonies formed from those individual cells. Take a sample of that colony, put it into sterile media, and now we have a pure culture. That's just one type of organism. And now we can assess that pure culture to determine traits about your organism, right? That's the whole point of getting those colonies. So, how do we do that? We use the straight plate method. It's the most common one. It's the one that you guys need to know. It's one we're going to do in lab. You put the crap down on your plate. Just it on there. You got a whole mish mash of cells. You can see that in this first area here. Look at all this. You got red and yellow and white all mixed up in together up here. You put it on that. You sterilize your little wire loop. You go back in maybe once or twice. It out again to kind of spread it out. Flame your loop again to sterilize it and get it completely clean. Go back in and you do that four times. Eventually, you're going to have spread out those cells so much that you'll get individual cells. If you let it grow, they'll pile up on each other as they are here. You can select one of these create the white culture, the red culture, the yellow culture right there. Three organisms that you can look at. So, that's how that works. And we'll do that in lab to get a better sense of how that works. Create your pure culture from that. Um, which what we started out with was all the mixture of the white and the red and the yellow. That's a mixed culture. It was like that when we got it. It's probably what you would get if you swabbed your throat and put it on a plate. Contaminated culture. You made your pure culture and now there's some other crap growing in it. You probably had your pure culture and something got into it. That's not the same thing as a mixed culture, right? So, I want you guys to just be aware of the difference there. The contaminated culture, that's you had your pure culture and something else got introduced from the environment. Typically mix culture, it started out that way. When you got your sample, started that way. Okay, we know pure culture is just one organism. All right, so in our five eyes, now we're into inspection and identification. Try to put push through this stuff real quick for you guys. Inspection, identification, essentially just doing tests, growing it on those special medias. Does it grow on this or not? Does it change the color or not? doing PCR tests which are genetic tests to see if the genetic genes are there or not. We'll talk about how that works in later chapters as well. So doing those tests, seeing if somebody has an antibbody for something. Um if if so an antibbody is a protein that is made by your body um to bind on to anything that's foreign. So if your body can see something as foreign, it can make an antibbody called it can make a protein called an antibbody to that foreign marker and it will bind to it. We'll talk about what the purpose of that is later on. But that's what an antibbody is, okay? Or your immune system. If you have an antibbody to HIV in your blood and I can detect that you have HIV antibodies, what does that mean? It means you have HIV. Why? Why does it mean you just seen it and got rid of it? Because once you have HIV, you have it forever. Now, uh, I had a student argument with me, argue with me, and not to say argue, but she brought up the point that you can become undetectable with HIV. Absolutely you can. You think those people who had tested positive for HIV virus who are now undetectable for HIV virus, meaning that the machines can't see that you have any virus in your blood. Uh, do you think those people still have antibodies to HIV? Yes. So that's typically what we will use to see if somebody has HIV because that tells us more about it than seeing the virus does. HIV incorporates its genetic information into your cell's genetic information. It literally puts its DNA into your DNA. How do you get that out? You cannot. There is no way. So once you have HIV, you have it forever. You can take medications to keep your body from making virus and shedding that virus into the blood which will make you undetectable. If the machine, if you go and get tested and I take a vial of your blood and that vial that I took from your body, out of all the blood in your body, that one vial that you sent to that machine has no virus in it whatsoever, you are undetectable. Does that mean you have no viruses being shed in your body whatsoever? It means you are undetectable. That's what it means. That means you should still be using protection. That means you should still be notifying your partners that you are HIV positive. If you guys encounter any of your patients that think that it is appropriate not to notify their patients that they have HIV or to use protection that they are when they are HIV positive and they are undetectable. You need to notify them that that is inappropriate and unethical behavior because they could still be transmitting HIV. HIV is a lifelong infection. Now, we don't think too much about HIV here in the United States because we're so aware of how to protect from it. And you'd be surprised probably the percentage of the population that has it. I don't know off the top of my head here in the US, but I'll tell you what percentage of the population is for sexually active adults in South Africa, 50%. That means half of the people in this room right now would have HIV. That is shocking. And it should have you really thinking about world health versus just United States health. and the need for more research into helping potentially cure HIV, which will mean removing that genetic information from their cells, which is a that's a monumental task. But anyways, tests like this exist and they're different for these different organisms for different reasons. We're going to learn about that in this class. We already talked about kind of the size of um our ukareotic cells like our own blood cells for example which you can see there on that second section microscopic view versus down at the bot very very bottom we have an hydrogen atom which is the smallest like true still atomic structure. Um pions are are proteins which are much smaller than viruses and polio virus is one of the smallest viruses that we know of. Um this puts it into scale. We're going to just briefly go through the microscope stuff and then we'll be done. Um, we're going to talk about the structures and the operating the parts of the microscope and how they work and everything in the lab. So, I'm not going to go over them too much here, okay? But you do need to know them for the lecture exam as well. This is how light travels through. It starts to face through the light bulb from the bottom up through the specimen on the slide, hits the first lens. That's your objective lens. The lenses that rotate objective lens that creates the real image. The first lens that first sees that specimen image creates the real image. It's going to go through some mirrors and out the eye lens, the ocular lens for another magnification that creates the virtual image. It's virtual because it's the second time we're seeing it go through the lens. Okay. Uh microscopes, we have magnification, resolution, and contrast. Uh magnification, how big we're making it, resolution, how clear the image is, and contrast. This is like gray versus light gray. um compared to black versus white just the ease of telling difference between structures. We talk about these guys um and magnification when you're mag when you're calculating magnifying power which I will have you do. Okay, but this is what I'm saying. Our ocular lenses are always 10x. And so you're always going to multiply whatever your objective lens is by your ocular lens. And so ours is always your objective lens which might be anywhere from four, 10, 40 or 100 multiply by your eye lens. It's always 10. So just add another zero on there, guys. Don't overwhelm yourselves, okay? To get your overall magnification. Refraction talks about where your light's going. So you know how we have in in rooms, we'll have light shining through glass and then when it hits the air, it causes the light to diffuse over. That's how we light rooms. Well, we don't want that when you're looking at an image on a microscope. What you want is that light to hit your specimen and to go straight to the eye if it could. But if it hits the air, the light rays from the image are just going to scatter everywhere. So, to keep it defined where we need it, we put oil. So, the oil, let's see, let's go to it. There it is. The oil is actually going to keep those light rays nice and tight up straight into that objective lens so we can see a clearer, more defined image. prevents that refraction, which is light ray scattering. Okay. All right. Um, you might prepare your specimens different ways depending on what you're trying to look at. You want to look at live specimens swimming around, then you want to use a wet mount. However, just wet mounts looking at actual living specimens. But you can't stain your cells if you do that and they're going to be moving around. You want to look at them in fixed in one place. You're going to want to fix them to the slide and use heat to do that. This kills the cells. It aderes them to the slide and it preserves their set of components so the things inside of the cells aren't moving around either. So that's the whole point of heat fixing. You can also use alcohol to fix these. Different kinds of stains such as basic and acidic. Basic we can think of positive. I think of a B looking more like a P and that's how I remember that those are basic and positive. Okay. Um but positive charges are going to be attracted to negative charges. Opposites attract just like a north pole and a south pole of a magnet. Okay. So positive stains are going to stick to your negative outside of your cells. We'll talk about why cells are negative in the next chapter. And then acidic have a negative charge. So they're going to be repelled by the negative like a south pole to south. Okay? So they're going to change. They're going to see the background. That's all that talk about there. And then we have some examples where we see the purple cells on the left and on the negative stain the purple background. Okay. Simple stains. We're just using one stain usually to stain the cell so we can see just some contrast. Provides contrast. Then we have differential stains that use different aspects of the stain to to bind to different parts of the cell.