This video is on proarotic pathogens and ukareotic pathogens. So we're going to start off with the proarotic pathogens mainly bacteria and then we'll move on to the ukareotic ones. So maybe we've seen this before. This is called a phogenetic tree. This is phogyny. It's basically the relatedness between different species. Okay. So this kind of shows that we all started from a common ancestor and then we turned into all these different types of fila and genre and species and so on. And so you can see at any kind of fork where it kind of splits. You can see where it used to be the same organism and then it evolved to become a different type of organism. For example, basillus, myopplasma and clustrdium were all the same organism at one point, but then they evolved into completely different genre. And then within these genre, there are different species. And so this is not something that we have to memorize, but it kind of just shows the diversity of bacteria and the evolution of all these different types of bacteria that we've been talking about so far. Now, not everything starts off as a pathogen. There are a lot of species of bacteria that have evolved to become pathogenic. For example, we've talked a lot about horizontal gene transfer, right? genes being transferred between bacterial cells. And we've also talked about how those uh genes can be transferred either through plasmids, transposons, and these often carry antibiotic resistance genes, other types of genes that can make um the bacterial cells survive better and it can cause it to evolve. And so all of these written in red on this slide are known human pathogens and the blues are not human pathogens. So you can just kind of see how things have evolved. Now whenever we talk about um the proarotic pathogens, we are going to discuss seven major fila of bacteria that impact our health that cause infection in us. And so um a few of these do have benefits to them. Most of them we're going to learn about different infections and diseases. Now the seven filyla are numbered here but they're not in any particular order. So we have firmacutes, actctinoacteria, proteobacteria, bacterioidites, spyites, cyanobacteria and chlamydia. So what we're going to do is we are going to talk briefly about each of these and then we'll start going into detail. So the firmicutes and actctinoacteria these two filyla include grandpositive organisms. So they're going to have a thick cell wall right because grandpositive bacteria they have multiple layers of that pepidoglycen. Now there are some examples of firmicutes that we're going to see in a minute that produce endospores. And if you recall the two genre that we learned that can make endospores are claustrdium and basillus. Under the film actinoacteria we have some bacteria such as streptoyces genus that helps us produce different types of antibiotics. So it's beneficial. Proteacteria is a very diverse film. It includes bacteria that have all these different types of metabolism. There are ones that are heterotroofs. There are ones that perform photosynthesis and proteobacteria um are often used in biotechnology which we've studied before. Bacterioides film these are gram negative proteobacteria are also negative by the way. uh bacteriooids are all rods. They're all basilis shaped and they are obligate anorobes which if you recall obligate anorobes they die in the presence of oxygen. They need a no oxygen environment. These are actually part of our normal microbiota in our intestines and so they're beneficial to us. However, they can be opportunistic pathogens. Spyroets, we already have learned about what shape those are, right? They have that coiled spiral shape to them. They have a very distinct shape um that make that differentiates them from other bacterial cells. We're going to talk about how they actually get that shape, that tightly coiled shape. Um spyroets, some of them are pathogenic, strictly pathogens that infect us. Some of them are just free living in soil in water in the environment. Um one example of a spyroet is burellia burgdorferryy. This spyroet bacteria is the cause of lyme disease. Then we have cyanobacteria. Now cyanobacteria are phototorophic right? They do photosynthesis and through photosynthesis they provide us with a lot of the oxygen that we breathe. They are included in uh marine watery environments. They can fix carbon dioxide and they can also fix nitrogen. So cyanobacteria actually are not pathogenic to us. There are no human pathogens here. They are only beneficial. And if you recall carbon or carbon dioxide fixation was when the organism can take carbon dioxide gas from the atmosphere from the air and convert it into usable forms of carbon and make all of its molecules. Chlamydia is the last film that we're going to learn about. Um chlamydia it obviously includes the STI chlamydia. So, chlamydia is a sexually transmitted infection um caused by some strains. Chlamydia can also cause um traoma which is an eye infection. It can also cause pneumonia. We're going to see in this video how a lot of different organisms cause different types of pneumonia. Now, organisms under chlamydia film, we call them obligate intracellular pathogens. That means that they need to be inside of the cells. They are only multiplying and surviving inside of the host cells otherwise they can't grow. They are also obligate parasites. That means they are we only have a parasitic relationship with them. There is no benefit here and they don't belong in our body. So I mentioned that pathogens evolve to become pathogens and they continue to evolve um in different environments. So there can be a bacterial species that is not pathogenic but it can evolve to become pathogenic. So where do these pathogens evolve? We have three we call them evolutionary incubators where new pathogens basically evolve and grow. One is zooonotic hosts. Zonoses are diseases that um are in animals but they can be transmitted to us. So within an animal, the pathogen can be in the intestines. It can interact and transfer genes between other species that are part of the normal microbiota of the animal. There's a lot of horizontal gene transfer that can happen. Um and so just in the microbiota or in the intestines of an animal, a pathogen can basically come about. The other evolutionary incubator are shelter species. So these are organisms that don't interact directly with us but they do provide shelter and environment for bacteria to evolve inside of them. This includes like nematodeses, earthworms. So different types of helmets, insects and so on. And then also the natural environment around us that is also an evolutionary incubator. So just outside in marine environments, in soil, um anywhere in the dirt, there are genes just constantly being sampled, constantly being passed between species. And so um a lot of antibiotic resistance genes can be made and passed around. Um and so there can be a lot of evolution there as well. So we're now going to go over in more detail in the specific fila and talk about some examples. So we're going to talk about firmicutes and actinoacteria first. Firmicutes and actinoacteria these are the grandpositive filyla. So they have grandpositive cell walls. However, there are a couple of differences between them. Now they both have multiple layers of pepidoglycan but they differ in their amount of GC base pairs. So if you remember guanine and cytosine base pair together right so G pairs with C A pairs with T right in the DNA. So for we call them the low GC's and we call actinoacteria the high GC's. So what does that mean? So let's say I have a DNA molecule that looks like this. And so now the complimentary strand. And so you can see the base pairing between these two strands, right? So looking at this, do I have more GC pairs or do I have more AT pairs? I have way more GC pairs compared to AT. Right? So if I have a lot more GC pairing relative to AT pairs, then that means I have a high GC content. So firmicutes, they have a low GC content. Actinoacteria have a high GC content. Another difference is that actinoacteria their pepidoglycan cell wall has additional unique waxy lipids inside of it. Keep that in mind. We're going to discuss it in a little bit. Okay. So here is that GC content explanation. Again, firmicutes have a relatively low GC content. Actinoacteria are called the high GC's. So let's go over some uh species under each of these fila some of which we have already learned about basillus anthraasis for example we've heard about now I mentioned earlier that firmicutes include sporeformers and remember clustrdium and basillus make spores firmicutes also includes non-sporeformermers. So let's go over the endospur formers first when we're looking at firmicutes. Basillus anthraasis which we know causes anthrax. Claustraiides difficil in other words claustrdium difficil. What does that cause? Antibiotic associated diarrhea. Clustrdium botulinum used in Botox but can cause botulism. Clustrdium tetany causes tetanus. So these are firmicutes and they are spore formers. Non-sporeformers in this film include interaccus which is part of our normal microbiota. Lactobacillus which makes lactic acid. Lististeria which is a big big deal. We have a lot of outbreaks of those stafylocus orius. It causes a lot of different types of infections. For example uh the one that we learned was toxic shock syndrome. So far there are also myopplasma. Myopplasma if we uh remember it lacks a cell wall. Myopplasma pneumonia is an example of myopplasma that causes pneumonia. When we're looking at actctinoacteria we've learned about coronacterium dtheria. They c that causes dtheria. This falls under the actctinoacteria film. And we also have mcoacterium species that fall under this film. So if you recall I mentioned that waxy lipid in the cell wall. If you recall micolic acids were found in the cell wall of mcoacterium tuberculosis and mcoacterium lepre. So again we're going one by one. So we're going to cover firmicutes. Now phylmicutes includes spore formers. Remember endospores, they are resistant to everything. They're apocalypse resistant. They're resistant to heat, to freezing, to drying. They're resistant to chemical disinfectants. They can survive anything and they can live for thousands of years and then germinate. So, one example of this is the genus basillus, right? Basillus um grows best by aerobic respiration and it makes these large cream off-white colored colonies. So if I were to grow basillus in a plate, I have a fresh culture of basillus on this augur plate and I left it out and then we went on summer break and then we came back after 2 months, what's going to happen to these basillus cells? They're going to start running out of nutrients, right? And when they run out of nutrients, they're going to say, "Hey, we're starting to die off." So what are they going to do? They're going to be begin sporulation and they're going to develop endospores. So if I come back after a month or so and I do an endospor with a with one of these colonies, I would see a lot of spores. Same with claustrdium, except clustdium are obligate anorobes. These are also spore formers. You can see these terminal kind of bulging swelling um spores over here in the clustdium cells. And two species that we have to know for this are clustdium tetany that causes tetanus and clustdium botulinum that causes botulism. So let's talk about claustrdium botulinum first. So it actually releases a toxin called botulism toxin. Um and so this is used for Botox. So the Botox basically what it does, what this toxin does, it's a neurotoxin. So it paralyzes the muscles. It does not allow the muscles to contract so that you don't make all of these lines and wrinkles and so on. So that's all good and fun and helpful, but um it can also be pathogenic. It can grow in the colon of young infants and babies and it can cause something called infant botulism or floppy baby syndrome and that's when um it not only infects the intestines but it can uh it can spread and it can cause paralysis of all the muscles in the body, the skeletal muscles, the respiratory muscles. And so none of the muscles have any tone. They just remain relaxed. they can't contract and that's why it's called floppy baby syndrome. Claustrdium difficil now it's known as clustradies difficil. This is a really really serious intestinal pathogen and remember it's antibiotic associated. So if there's a patient who's been in the hospital for a while on long-term antibiotics, a lot of different types of antibiotics constantly, their microbiota is going to be off balance. it's going to start getting diminished and that's going to allow claustrdium difficil to take this opportunity and infect the host. So it's usually with a susceptible host and claustrdium difficil again it makes spores and it's really resistant to a bunch of antibiotics and again it causes antibiotic associated diarrhea. Now firmicutes also include non-sporeformers. So let's talk about um a couple uh some examples of this. One example is lactic acid. This is grampositive. It's rodshaped and lactic acid bacteria include the genre lactocockus and lactobacillus. These are obligate fermenters. That means that they only do fermentation. Okay. And what were the products of fermentation that we've learned about before? Acids and alcohols. So these genre they turn sugar into lactic acid. So they're used in food products to make cheese and yogurt and so on. Another non-sporeformer under the film firmicudes is lististeria species. These are intracellular pathogens. They need to be inside of a host and then they can move on to the next host um neighboring cell. It can cause uh gastrointestinal infections. It can infect the nervous system. It can become a pretty big deal. It's a facultative anorob. And the other problem with lististeria is that it grows at cold temperatures. So it can survive and reproduce at refrigeration temperature. So that's bad news for us because we put things in the fridge so they don't get spoiled. Now we also have other um grandpositive organisms under firmicutes intera streptococcus stafylocus. So here on the left we see stafyloccus right it's caucus shaped spherical cells and they are in clusters. Here on the right in these two images we see chains of caucus shaped cells. So it's streptococcus. Let's talk about entocckus first. Interocco, like I mentioned earlier, it's normally part of our gut microbiota. It's normally in our intestines. However, if a hospital patient is immuno compromised, um they are extra susceptible, then it can cause an infection. So, it can be an opportunistic pathogen. Um it's known to cause urinary tract infections also known as UTI as well as bacteria which is bacteria in the blood. Stafylocus facultative anorobic we already know it's caucus shaped. It grows in clusters and it is part of our normal skin microbiota. It's also a halo file, right? It can survive salty environments. However, this can also be an opportunistic pathogen and it can be pathogenic. We know that it can cause toxic shock syndrome. It's one of the causes of pneumonia and it can also cause osteomiolitis which is infection of the bone. So if let's say I have a really big wound in my skin and staff orius infects that wound and I don't treat it or go to the doctor or take care of it, it can spread deeper and deeper into the tissue and eventually infect the bone and that's when it can be a much much much bigger deal. Streptoccus is also part of our normal microbiota. It's found in the oral cavity. It's found in the throat. So it can cause tooth decay. Some species of streptococcus uh grow in the on the skin or the intestines, but they're mostly in the mouth. Um streptococcus pneumonia is a species of streptococcus that causes pneumonia. And if you've ever heard of or had strep throat, which I'm sure a lot of us have, that's caused by another species of streptococcus. So it can also cause a lot of infections even though it's normally found on our body. And then lastly, myopplasma. Remember myopplasma the uh bacteria under this genus they do not have a cell wall because they normally live in the tissues of their host. They have lost the need for the cell wall protection. So they have undergone reductive evolution also known as degenerative evolution. So they don't really need it anymore. So they've evolved to not even make it. A couple of things that myopplasma species cause are pneumonia and menitis. Uh menitis is inflammation and infection of the brain and spinal cord lining. The meninges are the outer coverings of your central nervous system. All right, let's move on to the film actctinoacteria. Now acteria remember these are your high GC gram positives and their cell walls include unusual lipids like micolic acid. So if you recall these are acid fast organisms. So we stain them with acid fast staining rather than graham staining because those lipids don't allow them to take up that graham stain. Well, and an example of this that's we that we've previously studied is mcoacterium tuberculosis. Let's first talk about a beneficial bacterium under film actinoacteria and these are actctinomy. Actinomy are a specific type of bacteria that secretes a lot of agents. It secretes a lot of substances that we can use pharmaceutically. So um it has these branching filaments, these kind of branches that extend out and they actually release substances that we use as amunosuppressant medication, types of antibiotics, medications against tumors and so it has a lot of pharmaceutical use. So this is beneficial to us. However, there are actinoacteria that are not actinomytes and they do cause infections. For example, gardenerella vaginalis causes bacterial vaginosis, which is BV. If you've ever heard of BV, that stands for bacterial vaginosis. Coronacterium dtheria we've learned about it causes dtheria and remember that toxoid of it is put in the DTAP vaccine. Proprinoacterium, it's used uh for fermentation to make cheese. Cutabacterium acnes causes acne like the name might suggest. Lastly, let's talk about that the acidfast basili mcoacterium species. Remember that mcoacterium tuberculosis causes tuberculosis. Mcoacterium lepre causes leprosy and they have micolic acid in their cell wall which makes them unique. That's why they have their own staining method. But it also provides them with an advantage to survive longer inside of a host. And that's why TB often uh goes a long time before being detected. Also the its only mcoacterium tuberculosis only reservoir are humans. It only infects humans. So it's one of those diseases that's hard to research with. Now moving on to gram negative filyla. This includes the filyla, proteobacteria and bacteriides. So proteobacteria they are gram negative. They include both basillus shaped and caucus shaped bacteria. Phylm bacterioides are also gram negative. Um they are rodshaped and they're mostly anorobic. So let's talk about proteobacteria first. So there is a family under the proteobacteria film called interobacteria and includes it includes a lot of gram negative um basilli that cause infections. These are facultative anorobes and they are modal. So that is bad news for us but it's a survival advantage for them. Under this family there are commensils and there are pathogens. That means commensiles are basically the ones that we have symbiotic relationships with and it's like beneficial and then pathogens are the ones that only cause infection. For example, there are a lot of different strains of E.coli. There are some E.coli strains that are are commensiles. They're normally in our intestines and everything's fine. And then there are just strictly purely pathogenic strains of E.coli as well. Some other genre under this family are salmonella. So salmonella species they cause entitis which is um inflammation of the entic system of the intestines. Typhoid fever if you've ever heard of that that's caused by salmonella. Klebella is another genus and it is the uh leading cause of pneumonia that you get from the hospital. So if you've ever heard of a patient going to the hospital for one infection but then while they're in the hospital they get infected with pneumonia most of the time that's klebsella pneumonia doing that and then your cineia pestus which is the cause of the bubonic plague. So again they're all facultative anorobic they're all rodshaped they can be in our digestive tracts or they can be in the outdoor nature environment. Some of them form bofilms and a lot of them have fleella so they're able to move. So an example here of a flagagillated organism is proteus morabilus. Proteus morabulus is known to cause really serious bladder and kidney infections. So this is the one where if there's a complication of the uh urethral catheterization, the catheter was not placed correctly or it wasn't changed often enough and there is bacteria in there. If it's proteus morabulous, it's able to then travel, it can travel up the tube. It can travel through the patient's urethra and cause a go into the bladder and cause a bladder infection. It can then continue to go up all the way up into the kidneys and cause kidney infections. So it can be a really really big problem. And as you can see it is heavily flagagillated. It has a lot of fugella super modal. Um and so that's why it can travel along that catheter. And you can see a colony here. This is called swarming behavior. So do you see how it kind of grows kind of swimming out and making these rings? This is a really big unique characteristic of proteus colonies. Now what about urinia? Urcinia pestis like I said it causes the bubanic plague. Your pseudotuberculosis is another species ofia and that causes gastrointestinal disease. So it causes digestive infections from um contaminated food, contaminated drinks. So the reason I kept this in here is because your sinia pseudotuberculosis and your pestis are almost identical genetically yet they cause totally different diseases. So pretty interesting. Okay. Another family here under this proteobacteria film is pseudomonier. This includes pseudomonus aerogenosa. Now normally it is fine. Uh it's in soil outside. It is a decomposer. So that's beneficial. But it can be an opportunistic pathogen. So if someone has surgical wounds that are prone to getting infected, um the lungs of cystic fibrosis patients often get infected with sudamonus aerogenosa because those patients are so susceptible and they're compromised. It can form bofilms. Um so it can be a really big deal as well. Okay, some other examples. Vibrio. This bacterium lives in water environments, marine environments. And so in areas where there isn't enough sanitation, where there isn't access to clean water, that's where this is a big problem. Not as much over here, but it causes the diarrheal disease called chalera. And this can get pretty severe because um having cholera results in losing about like 12 lers 15 lers of water from your body per day and so someone can get super dehydrated to the point where it can be fatal. Bordatella pertasus this is the causes pertasus which is the whooping cough and that's another example. The pertasus toxin that's what we put or the toxoid is what we put in the DTAP vaccine. Niseria gorrhea causes the sexually transmitted infection gonorrhea. Another species of niseria called niseria menitis causes menitis which we've seen earlier. Hemophilus influenza, Morazellais. These are other causes of pneumonia that belong to this film as well as H pylori or helicoacttor pylori. We've already learned what this causes, right? Gastric ulcers and gastric cancer. But have you ever wondered how H pylori is able to survive in the stomach? We know the stomach is a really really acidic environment, right? really low pH and not much can survive there. So, how does this bacteria survive and reproduce there and live its life there? Well, H pylori releases an enzyme known as urase. So, make sure you make a note of that urase. This enzyme uras it releases and uras neutralizes the acid around it so that it's able to survive in there. Okay, we also have symbiotic organisms under this film. These are riseobium, brady ryobbium and syinoor ryobbium. These we call them endo symbions of plants. So if you look at this image over here, here's a plants and they're usually like legume plants like soybean plants. If you see these little bumps here, these nodules, this is where um these organisms riseobium, brady riseobium or syrobbium actually um reproduce and live. So they have like this symbiotic beneficial relationship with the plant because the plant provides them with this shelter for them to reproduce and in turn they fix nitrogen for the plant. And if you recall nitrogen fixation, taking nitrogen atoms from the atmosphere from nitrogen gas and making it and turning it into usable forms of nitrogen. Now there are uh some organisms under this film that we say are predatory and they can actually attack other bacteria. Um one example of this is delibrio. These species can attack E.coli actually. Okay, moving on to the next film bacteriodites. These are obligate anorobes and remember that our intestines, our colon is an anorobic environment. So these are part of our normal intestinal microbiotum found in our colon, obligate anorobes, and they help us break down things that we or our body can't break down like sugar derivatives, toxins from plants. So they can actually break those down by fermentation. So we have a good relationship with bacterioides. However, if species of bacterioides um leave the intestine and they're somewhere in the body that they don't belong, then they can be an opportunistic pathogen. So, for example, if someone is having abdominal surgery, like a C-section, it's really, really easy to nick the colon or cut the make a cut in the colon by mistake. And if that happens, the bacteria can escape the colon, go into the abdominal cavity and cause infections and absesses. So, that's when it's um bad news. Now, moving on to the phylm spy. Remember these have that unique spiral shape to them and this is due to their fleella. So I'm going to go over the structure of a spyroet. Now spyroets have that out an outer membrane an outer sheath and the space between the cell and that outer sheath is called the periplasm or par perlasmic space and they also have fleella. Now the fleella circles back around the cell and kind of coils itself wraps itself around the cell causing the cell to turn into this coiled structure. This is advantageous to the spyroet cell because it helps it navigate very viscous thick environments. The mucus in our body that's there to protect us, it can travel through that mucus and so it provides it with an advantage. Um two examples of spyroet species are trypema paladum which is the causitive agent of syphilis and borellia burgdorfery which we already said is the cause of Lyme disease. This slide over here is just the explanation in writing rather than using the diagram. Now not all strains of tryponyma paladum cause the STI syphilis but some strains do and you can see in this electron microraph this spiral-shaped cells. The next film is film cyanobacteria. Remember these are photo troughs. They they are photosynthetic. They're found in marine water environments. They can fix carbon dioxide. They can also fix nitrogen. and they provide us with a lot of oxygen. So they are only beneficial to us. And if you've ever seen lychen, maybe when you go on a hike growing on a tree trunk, growing on rocks or on the floor, lychans are actually a symbiosis between cyanobacteria and fungi. So they're this beneficial relationship between cyanobacteria and fungi and they are beneficial for the environment. Now the last phylm here is phylm chlamydia. Um and so phyylm chlamydia like I said they are obligate intracellular pathogens. They are obligate parasites. So they only cause infection. Now even though these chlamydas are not myopplasma they're totally different. They also lack a cell wall because they are are just strictly intracellular. They've lost the need for it. So here is the life cycle of chlamydia. Now chlamyia has two forms. The cells can be as in the form of elementary bodies or they can be in the form of reticulate bodies. Elementary bodies is kind of like the inactive form and this is the form in which it enters and exits the host cells. The reticulate body is the reproductive form. It's the active form. So as elementary bodies they enter into the host cell. Elementary bodies turn into reticulate bodies for reproduction and activity. And then once they want to leave the host cell, they'll turn back into elementary bodies and lice out of the cell and move on and infect other hosts. Now there can be a complication if a patient has chlamydia. Um they have this STI, they have this infection. um if it's not treated, if it's recurrent, if it's persisting and they haven't treated it and it's lasting really long, this leads to chronic inflammation in the female reproductive system. So, is chronic inflammation a good thing or a bad thing? It's a bad thing. So, whenever there's chronic inflammation anywhere in damaged tissues, tissues that have a physical trauma or a wound, there's a lot of scar tissue that builds up there. that's part of your um kind of your wound healing process. However, if too much scar tissue is built up, it can cause obstructions. It can block the organs and block um tract and all that stuff. So, if a person has a persistent infection with chlamydia that's not treated or cured, um then there's going to be a lot of inflammation here in the uterus, the fallopian tube, and the ovaries. And all this scar tissue buildup can cause infertility. This complication is known as pelvic inflammatory disease. Next we are going to discuss ukareotic pathogens. Now remember these are going to be different than bacteria. They're different from proariots because ukareotic cells um remember they have a nucleus and inside the nucleus instead of the circular chromosomes that bacteria have ukareotic cells have linear chromosomes they have other organels like the endopplasmic reticulum they have the golgi mitochondria chloroplasts and so on. So their cells are very different. So we're going to go over some different types of pathogenic ukareots for example fungi. Um we're going to look at prozzoa. We're going to look at helmets. So let's start. Let's talk about fungi first. Now fungi can be unisellular or multisellular. Unicellular means that they are singleselled and single-sellled fungi we call them yeasts. Yeasts are capable of both sexual and asexual reproduction. So they can go either pathway. Um asexual reproduction would be through butdding. So they just like butt out a copy of themselves essentially which you can kind of see right here. Now whenever um they and all fungi they have spores, okay? And these spores are basically found on a structure called an ascus. So the ascus has spores all over it and that contributes to the sexual reproduction. And so make sure you note that. You don't have to know the whole life cycle, but make sure you note just the things that I went over. There's also filamentous fungi. These, like the name suggests, they have this filamentous filament look to them. They have these branches that kind of extend out and produce something called a mycelium. And these branches are called hyphi. And remember fungi their cell wall is made up of kiten whereas the cell wall of bacteria was made up of pepidoglycin. All right moving on to prozzoa. Now prozzoa are classified based on what structures they use for motility. Whether they use pseudopods, fleella, psilia. So let's go over these different categories. So the first category of prozzoa that we're going to discuss are amiebas and there are two types of amiebas that we can see. We have loed amiebas where you can see the pseudo pods are really bulky. And then there are filamentous amiebas which in which their pseudopods are very very thin and they look kind of like needles. So two different types of amiebas. What are pseudopods? Pseudopods are extensions of the organism that allow it to move and travel as well as engulf its food and its prey. So an example of an amoeba is antimibba hytolytica. This species causes intestinal amiebasis. It actually ingests or eats up the host's red blood cells. So, let's say you're on vacation, you're by the pool and you want to order a little mojito, right? However, the mojito is contaminated. It's contaminated with cysts. And cysts are a structure where the cells of that amoeba are inside of. So, the cells of the prozone are inside of cysts. So, let's say obviously these are microscopic. We don't see them. So, we accidentally ingested it. The cyst undergoes a process called existation in which it releases the eggs and turns into trophoites. Remember trophoite we looked at in lab. It is the adult active form of the cyst of the prozzoa. So the trophoite can multiply. It can make more copies of trophoides. It can revert back into cyst form and the cysts can leave through the feces. Trophoites can also cause a more severe complication where they spread through the bloodstream to other organs and cause a more serious infection rather than just the intestinal infection. Another disease involving amiebas is keratitis which is infection of the cornea. Now the cornea is the clear layer that protects just this part of the eye. That's the cornea. that can be infected and the genus here is aanthamibba. Aanthamibba is an amoeba that infects the keratin layers of the cornea and it causes cloudiness and obstructs vision. All right, the next category are ciliates siliated prozzoa. These have psyia. So they're covered with these hairike um structures and with the help of microtubules they move around. So they are going to allow these organisms to be modal and move around as well as consume their prey. So you can see here an example is a parramium. You can see all little hairike extensions all of the psyia surrounding it again letting it travel and letting it eat. Ciliates eat um algae and ciliates are consumed by other protozoa amiebas. So amiebas eats ciliates. Ciliates eat algae. The next type of prozzoa are a epic complex. Apicomplexins um include a lot of parasites that infect us. For example, plasmodium species. Different species of plasmodium cause malaria. So this is caused by a protozonean by a parasite. And these are called apicmplexins because they have this special structure within them called the apical complex. and the apical complex allows them to enter into the host cells. Now let's look at plasmodium as an example. Again there are different species of plasmodium. There's plasmodium falsiferum that we're looking at now. There's plasmodium vivac. They both cause malarium and they actually infect our red blood cells and kill the red blood cells. Now plasmodium species have two forms. They have the mirazoite form which is the form where they are invading and entering a cell and they also have the intracellular form that kind of has like a ring shape which you can see in this microscopy image. So here is the mirzoite form of the plasmodium and here in orange down here is the apical complex that allows it to attach and invade and enter into the red blood cell where then plasmodium will turn or convert into the intracellular ring form. When it wants to leave it will burst out of the red blood cell causing the red blood cells to die. All right, we also have flagagillated parasites which obviously have fleella. These are also called metammonads. Um, and so giardia lamblia is a common example of a flagagillated protozoan. It's found in water outside like streams and lakes and in that way it can be ingested and it can cause intestinal infection. Now we're going to move on to helmets and arthropods. Helmets are parasitic worms and they also are categorized into different classifications. So we have nematodes which are the round worms. So they literally are round. They have a cylinder shape to them. Trimmatodes which we also call flukes or blood flukes we've seen. These are flatworms. They're ovalshaped. Um and they have no outlet. So a lot of these worms they have a very very simple digestive tract. We call it a digestive tube. Some of them have an outlet where they can expel their wastes and some of them don't. So roundorms or nematodeses their digestive tube ends in an anus. So they can expel things through the anus like waste. Whereas tmatodes their digestive tube ends in a seeum. They don't have an outlet. So they have to get rid of the waste back out of their mouth. Tapeworms are also flatworms that are segmented. We call them cestoades. And they have this sucker head structure that we'll see in a minute that allows them to basically um attach to the intestinal lining and basically grow. And they grow in these segments that contain both male and female reproductive structures. Okay. So let's go over some life cycles here. The first one um we're going to look at a couple of examples of nematodeses. One are pinworms. Pinworms are tiny tiny white nematodeses and the species here that we're going to cover is entropobius vermicularis. This is transmitted fecal orally. So let's say um let's say this little girl touched something and then that was contaminated with these nematode eggs. Okay, these pinworm eggs and then she ingested it because she's a kid. She puts her um hands in her mouth and so on. So he she injected injected she ingested these pinworm eggs. They will travel to her intestine. They will bind there. They will grow into larvae and they will grow into adult worms. And when the female worms go to the anus, that's where they're going to release their eggs again for that life cycle to continue. And when the eggs are being released, it causes a lot of peranal irritation. and itching in that uh anal area. And so if this little girl, again, she's very young. If she's like, "Okay, it's itching. I'm going to scratch it." Then she can touch something and again it can go and be transmitted to the next host. Other examples of nematodes are hookworms. These include ankle stood and nicer americanis. Now these um actually they're hookworms. So they literally have like this hook like head. They attach to the skin and they enter through the skin. So if someone has a cut on their foot and they're walking barefoot in the soil and the soil is contaminated with these hookworms, they can actually latch on, enter through the skin, go into the blood, travel from the blood into the lungs, and whenever it causes irritation, that um host, that individual would cough. And once they cough, they cough that parasite up into their mouth and then accidentally swallow it. Then it goes down the digestive tract right into the esophagus. And once they reach the small intestine, they latch on and they basically eat the red blood cells. Um, their offspring will leave the host through feces. Okay. An example of a round worm is ascarus lumberccoides. These eggs can be ingested from soil. The worms get bigger and bigger as uh they go through the digestive tract and again it's causing an intestinal infection. Now this can get pretty serious if it spreads to other organs like the lungs then it can be fatal. Moving on to tapeworm. So these are our sestos and these are transmitted as larvae in uncooked meat. So if the cook is under if the meat is undercooked or uncooked depending on the type of meat. So if it's pork the species is tinyolium that's found in undercooked pork in uncooked beef it's tiny sagonatada that's found in there and in raw fish it's dilabothium or sushi it's dyrium. So these are different species in different types of uncooked meat. Now, these, like I mentioned, they're segmented and they can grow up to 15 m in length in the digestive tract. So, let's go through the life cycle and transmission of a tapeworm. So, let's say you have this cow, right? The cow um ingested the eggs of a tapeworm just naturally exposed to it and the eggs go into their muscles and they turn into larvae. This cow is then used to make steak at maybe a restaurant you go to to celebrate your A+ that you got in this class. And then you basically are whenever you order a steak, for example, it's the muscles of the cow. And so there's larvae if it's contaminated with this specific cow, you are taking in the larvae of the tapeworm. And like I said, it has like this sucker hook structure. Once it reaches the intestines, it'll latch on to the lining of the intestines and it'll keep growing longer and longer in these segments known as pra I can't talk tonight. Pragotids. So they grow in these segments called pragllodids. And if you see all these little tiny dots inside each plloaded, there are a bunch of tapeworm eggs. The eggs can be released from the proglotteds as um they exit through the anus as in the feces. So that's the life cycle of a tapeworm. Lastly, we're going to talk about arthropods. These include like ticks, spiders, mites, um and so on. Um so these are arthropods. Think of insects. So um let's go over some examples. Um let's talk about mites. An example of mites are sarcopti scabier. Saropti scabia are an example of mites that cause scabies. Now scabies can occur in humans or in animals. And these mites actually go underneath the skin. They burrow under the skin and they can lay eggs and they cause a lot of irritation and they move around. So they enter into the skin, they lay eggs and they kind of move. So they kind of make like these little track marks. That's like one of the characteristics of scabies. Ticks are another example, right? Ticks can carry bacteria that causes Lyme disease. So remember the bacteria Borrellia burgdorferryy is the one that causes the Lyme disease, but the tick is what carries it and can transmit it if they bite you. And it's not any tick. It's specifically the tick of this species, Exod scapularis. only this tick can be a vector for borellia burgdorferryy. Um, and so if this tick is carrying that bacteria and it bites you, then you would get the Lyme disease infection. And we're going to talk more about Lyme disease in a later chapter. Now, some parasites, we call them ectoarasites. That means that they don't actually enter into the host, but they're on the surface of the host. Like for example, lice. lice stay in the fur or the hair, but they don't actually go inside of the host or inside of the skin. So, this we would call them wingless ectoparasites because they don't have wings. But other insects can be parasites and can have wings. All right. So, this concludes the proarotic and ukareotic pathogens.