Wisconsin Public Television University Place  Microbes and Our Diet, Digestion and Disease  Greg Richards  7/24/13 UP900  cc >> Welcome everyone to Wednesday Nite at the Lab. I'm Tom Zinnen. I work here at the University of Wisconsin-Madison Biotechnology Center. I also work for UW Extension Cooperative Extension. On behalf of those folks and our other organizers, Wisconsin Public Television, the Wisconsin Alumni Association and UW-Madison Science Alliance, thanks for coming to Wednesday Nite at the Lab. We do this every Wednesday night, 50 times a year. Tonight it's my pleasure to introduce to you Greg Richards. This is Greg's second talk here at Wednesday Nite at the Lab. Greg grew up in Sheboygan and went to Sheboygan South High School, then he came here to UW-Madison for his Bachelors, his Masters and his PhD. We call that being on a roll. 

He studied microbial sciences. He went to the University of Illinois at Urbana-Champaign for 3-1/2 years of post-docking. In September of this last year he started as an assistant professor at UW-Parkside. UW-Parkside is a place near and dear to me because it's on a place that was called Petrified Springs Park. I think the park is still there. That's where my family reunions were held all though the '60s. That's actually where I was when Apollo 11 landed on the moon. UW-Parkside has got a great name because it's between Kenosha and Racine. They decided, we'll call it Parkside instead of UW-Racine/Kenosha. >> It's catchier that way. 

>> It is catchier that way. Tonight we're waiting for Jennifer Lawrence to arrive. She should be here any moment, because Greg's going to talk about bacterial hunger games. If you've been watching the news over the last four months, five months, six months, about some of the shifts and how people are looking at bacteria inside us and what they do, and all the really good things they do for us. I think you're going to get an idea of some of the cool ideas that Greg's going to share. Please join me in welcoming Greg Richards to Wednesday Nite at the Lab. [applause]  >> All right, thanks a lot everybody. Can you hear me all right? Yeah? Doing good? Okay, cool. Thank you very much, Tom, for that kind introduction. As Tom mentioned, this is my second Wednesday Nite at the Lab. 

I feel very honored that he, for some odd reason, thought it was a good idea to invite me back at some point. >> You answered my e-mail. >> Ah, that's it. I got ya. I'd like to also thank all of you for coming, especially on this gorgeous summer evening. Tom, I think that you've got to think about maybe Wednesday Nite at the Terrace in the summertime as opposed to Wednesday Nite at the Lab. Just throwing that out there. You can workshop it a little. All right, so as Tom said, I also did my Bachelors and my PhD here at Madison, so I'm always happy to have another reason to come back. Especially this time, to get to talk to you guys about one of my favorite subjects. 

Right, so today we are going to talk about how microbes effect our diet, our digestion, and also a little about disease. But we're going to kind of come at it from a funny angle. You might not have thought about it before. I should also mention, this is not a topic that I do my research on, but it's a topic that's near and dear to my heart. All right? Okay, so when it comes to microbes usually we only hear about the bad apples, particularly in the way that the media tends to portray microbes. I'm going to give you a few examples that I found without even trying. Just as a few examples here, last summer in the southern US there was an outbreak of West Nile virus, undoubtedly serious. A little more recently, you may have heard about this. In March there was an outbreak of norovirus which is generally a form of food poisoning on a Royal Caribbean cruise ship. You may have heard occasionally of people getting sick on outbreaks on cruise ships. 

Norovirus is usually responsible for that. And, man, I gotta say, you know, if you're on the Love Boat, maybe the "exciting and new" part, this isn't exactly what you're looking for. Right? Okay, it's not really such a great thing. A little closer to home, by a show of hands. How many of you went to either the State Fair or your county fair last summer? Anybody? A few of you? Okay, cool. Well, guess what. At both the State Fair and some of the county fairs there were swine flu outbreaks last summer. Not too fun. When people get in close proximity to pigs that kind of thing can happen, including at my current county of Kenosha. That was good alliteration. 

I was not actually planning that. Current county of Kenosha, I've got to remember that. Even closer to home than that last fall, there was an outbreak of shigellosis, generally another type of food poisoning, right here in Dane County. A lot of those cases were in Madison. And as Tom mentioned, I am from the great city of Sheboygan, bratwurst capitol of the world. Unfortunately, recently there was also a tuberculosis outbreak there. I don't know about you, but a lot of people tend to think of tuberculosis as the this kind of old timey, romantic, tragic, dying-of-consumption kind of disease in the 1800's. It's actually still around, and strains of it are becoming kind of resistant to the treatments that we have for them. There's been kind of a resurgence in that. Even more recently than that, just this month, really last week, it was reported that there was an outbreak of Legionnaire's disease in Milwaukee County. 

This is a pulmonary infection. You guys get the idea. When it comes to media coverage of microbes, what are you usually hearing about? The bad stuff. In fact, if you had to guess, based on media coverage, what percentage of microbes might you guess cause disease? >> 100. >> 100, yeah, that's a good answer. Anybody else? Any guesses? We're going with 100? That's cool. I've never had anybody stay. You're all good with that. I've never had everybody-- Usually people are like, no, it's 35, 45, whatever. All right, the fact of the matter is it's actually less than 1% of microbes that cause disease. 

In fact, a lot of them do some pretty good stuff too. That's what we're going to focus on into this talk. Yes, sir. >> Disease in humans, or disease period? >> In general, but I'm talking about ones that cause disease in humans in particular. That's usually what, again, are reported in the media and people hear about. All right, so hopefully you guys get the idea. While it's undoubtedly true that microbial diseases are serious, they're not exactly representative of the microbial population as a whole. To kind of give you an idea of how inaccurate this is, it's kind of like basing your opinion of the entire human race on say, Lindsay Lohan maybe, or Honey Boo Boo perhaps. You guys get the idea. It's not exactly accurate to look at the news coverage of these guys and say, oh, all people must be like that. 

I think this is especially true in this day and age where ever single bottle of soap carries a bacterial death warrant on it. And I mean every single bottle of soap. Everything says antibacterial, right? We're going to talk about today also why this may not necessarily be the best idea. In particular today-- Well, I just have to say as an aside. Can you imagine being so unwanted in the world that even the soap bottles are hoping for your imminent demise? That's not a happy place to be in, okay. Today we are, again, going to accentuate the positive. We're going to take a few moment to celebrate the ways in which microbes can enhance our lives. Today we are going to cover, as I said in my title, the Mastery of Microbes over, first, the delectable. One of the big things they do for us is that they help us to make many common and delicious and, also healthy, foods. Some of them maybe aren't so healthy, but they're still delicious. 

We're also going to talk about how microbes effect our digestion. They help us make, absorb, and digest nutrients. Finally we're going to wrap it up with the death-defying. Microbes that are associated with humans actually do a lot of things to help us fend off other microbes that cause disease. First, the delectable. Without microbes you have to try to imagine a world without cheese, yogurt, other dairy products. That's especially difficult and inconceivable, I think you guys probably know, in the great state of Wisconsin. In addition, we wouldn't have leavened bread, no delicious, tasty alcoholic beverages. That's another big one in Wisconsin. You guys are probably familiar with some of these things. 

You may also know that microbes are responsible for helping us make them through the process of fermentation. Microbes, including certain yeasts and bacteria, are able to eat sugars, and in exchange, they convert them into alcohol, various acids and gas. Those are the processes that allow us to make some of these delicious foods. These foods here are ones that people maybe have heard about microbes being involved with. If you look at the side of your yogurt container you see these long, complicated scientific names that are the microbes in them. But there are also other foods that microbes help make that sometimes people aren't as familiar with. One of the best ones, given my own personal German heritage, is sauerkraut. In addition, microbes are needed to ferment soy sauce, and also to bake certain types of pickled foods, and things like olives, in particular, green olives. Black olives are actually fairly mild, but green olives are pretty unpalatable to people unless there's a little microbial fermentation to kind of make them taste a little better. Then one of the other big ones is chocolate. 

A lot of people actually don't know that we wouldn't have the chocolate we know and love without microbes. In addition, you probably recognize that a lot of these foods can be kind of acidic, things that are pickled, that kind of thing. Microbes often produce acid when they ferment foods. That actually can help make, not just the foods taste good, but it also can help prevent things from spoiling. The reason for that is that many of the bad microbes that would cause food to spoil actually have a hard time growing in acidic foods. That's another big benefit of microbes when it comes to food. They can help curb the spoilage that goes on with certain foods. We're going to go over one of these examples in a little bit more detail because it's very near and dear to my heart. I'm sure a lot of you are fond of it too. And again, it's not something that people are always familiar with. 

That one is chocolate. Again, without microbes we wouldn't have the delicious chocolate that we know and love. Or at least chocolate would not taste like the chocolate that we are familiar with. It would be far more bitter, borderline unpalatable. Chocolate fermentation is not actually a new thing. It's a pretty ancient process. The Aztecs are often given credit for inventing this process. How it works is that the ripe cocoa tree pods that you see here, as an example, when it's time to harvest them, they're cut off the tree and they're also cut open. When they get slashed open, that's when the fermentation process starts. The earlier the better as far as this sort of thing. 

They're usually slashed up as soon as they're taken off the tree. Then the seeds and the pulp are moved out of that and they're moved into what's called a sweatbox. This is essentially a place where the fermentation process can take place. There are other variations on this, including you can actually just bury them in the ground and cover them something such as banana leaves. This is another variation on it that's done more commonly. The next step in the process is where we get to the good stuff, to the microbes. I'm a little biased with this. I am a microbiologist. But again, without this part, we wouldn't have the chocolate we know and love. Yeasts naturally present in the environment are responsible for initially breaking down the pectin that surrounds the seed. 

It's kind of this hard, unpalatable coating. At this point the sugars that are present in the seeds get fermented. Again, the yeast, they're using it as food, and in exchange they convert it into ethanol and gas, in particular in this case, carbon dioxide. All right, so there is a problem though, at least as far as the yeasts are concerned. As this process goes on the temperatures increase and the alcohol concentration that's the end product they're producing keep increasing. Eventually it stops the yeast in it's tracks. It's too high of a concentration for it to still be able to grow. At this point there are other microbes for the next step. These microbes are called lactic acid bacteria. These are the ones of yogurt fame. 

Again, if you looked at the side of your yogurt cup, it's closely related to these guys. These guys, during this process as you might guess from their name, are able to produce certain types of acid. This is really one of the key steps in the production of chocolate. The reason for that is that this acid is what allows other certain bacteria to grow. These bacteria are really providing one of the key steps in developing chocolate. These bacteria actually do a different kind of fermentation that ends, not in making alcohol, but in making acetic acid. You're probably familiar with acetic acid in the form of vinegar. It's just dilute acetic acid. Acetic acid, again, is absolutely essential to the chocolate making process. The reason for this is that it actually kills the sprout that's living inside of the seed. 

Obviously you don't want your chocolate bars germinating on you. That's just not something-- Calamity can ensue in that kind of thing. It's not a good thing. All right, so more importantly also, actually this acid production contributes to a lot of the delicious flavors that are associated with chocolate. And also, again, kind of breaking down some of the unpalatable parts of the chocolate seed into the form that we recognize. The fermentation process takes about six days or so. It's very important to get it just right. If you stop it too soon you're going to keep that chocolate way too bitter and unpalatable for us. If you stop it too late those microbes are going to grow out of control and they'll start to degrade the entire seed, chocolate bean, and then you're going to get some bad tastes associated with that. If all goes according to plan the end product of this process are the fermented seeds. 

That is what you're maybe familiar with as actually being the chocolate beans. The beans are way at the end of this whole microbial process. Once that beans are done being fermented they are usually at that point passed on to the chocolate manufacturer. There they are actually dried and processed into chocolate. They can be sun dried or dried in an oven. Then they get roasted. That process also kills most of the microbes that are present so don't have to worry about them being in your chocolate. All right, so hopefully you can get from the brief examples I gave you, as well as this more detailed example, microbes are really essential to a lot of our diet. In fact, you might say that the impact of microbes on our diet is truly astronomically and gastronomically unfathomable. There is one other example that we need to go over before we move on from this part of the talk. 

This may be more relevant to the great Utopian dairy state of Wisconsin than anywhere else in the world. The reason is that microbes are absolutely essential to producing cheese and a lot of other dairy products. What makes this dairy state so great? Well, I'm going to go over a little bit of brief history on that. First, by 1915 Wisconsin was actually the leading US producer of dairy. It's still the leading US producers of cheese by far. You may be familiar with the fact that, sadly, in the 1990's Wisconsin lost the top milk production crown to California. But maybe that's not such a terrible thing when you consider that 90% of our milk goes into making cheese. We're going to talk about that in more detail. Hopefully, by the end of this you don't have to worry at all. Wisconsin's status as the dairy state is not in doubt. 

Okay, a little bit of background on what dairy means to the state of Wisconsin. It means more to the state of Wisconsin than citrus means to Florida or potatoes mean to Idaho. In fact, it generates almost $27 billion a year for the Wisconsin economy. That's three times as much as citrus generates for Florida. It's about ten times as much as potatoes generate for Idaho. And again, a lot of this dairy product is that milk. It's going to go into making a lot of the cheese varieties that you see. The reason that this is important to Wisconsin's title as the Dairy State is that Wisconsin makes more varieties of cheese than any other state by far. We absolutely dwarf our closest competitor which is California. Wisconsin makes about 600 different varieties of cheese. 

Again, you may be wondering how this is getting back to the microbes, but to make all this cheese what do you need? You need the microbes. This is especially relevant to state economy because it's a wonderful time to be in the cheese business. The fact is that since 1975 American consumption of cheese has more than doubled. You can debate if you want whether that's a good thing health wise, but it's a really good time to be in the cheese business. That's actually is really reflected in Wisconsin. You can see that we have over twice as many cheese plants as the closest state, California, again. In fact, cheese means so much to this state and our way of life that in 2010 the Wisconsin state legislature tried to adopt our official state microbe, lactoccus lactis. You might think this seems like kind of a frivolous or silly thing to do or for politicians to spend their time on, but when do politicians ever do anything frivolous or silly. That never happens, right? But it's not really when you look at the impact on the economy. And at any rate, is it any more silly or frivolous than having a state bird or a state flower? You know, I like the robin and the wood violet at much as the next guy, but are they pumping tens of billions of dollars into our economy every year? I don't think so. 

I think you can make a case for this being a legitimate thing that should happen. But again, I may be a little biased being a microbiologist. What is lactoccus lactis do that is so special? Well, it makes certain kinds of cheeses. In particular, it's responsible for making cheddar, Colby, Monterrey jack, Camembert, also, Brie, Roquefort, cottage cheese, cream cheese, sour cream, and not to mention buttermilk. It actually is super-important to making a lot of these delicious things. Unfortunately, although the state legislature was able to pass this, the state senate did not take it up. Tragically, we were not able to make this happen. This is even sadder because recently, in May, Oregon beat us to the punch. They became the first state in the US to name an official microbe. This first official state microbe was saccharomyces cerevisiae. 

This is also known as brewer's yeast. It's needed for making beer and also other tasty alcoholic beverages. This is a big business in Oregon as it is in the state of Wisconsin. Hopefully, we can kind of get things back on track, help Wisconsin get it's act together and make this happen. You just watch. All the cool states are going to be having their own state microbe, I tell ya. You just wait and see. It's gonna be a thing. Okay, so that's it for the delicious aspect of my talk. In addition to all of these wonderful things that microbes do for our food, they actually help us to use our food as nutrients. 

In other words, microbes help us to digest. Before we get to some of the benefits though, I kind of gotta give you a little bit of context here. I just want to give you a little bit of background information about these microbe that are associated with people that help us digest. To put things in a little context, the current population of humans on planet Earth is about seven billion, a little over 7.1 billion. I looked this morning. I hope that you can forgive me. That's as accurate as I felt like getting. Give or take about seven billion, all right? Each human being, on the other hand, is made up of 10 trillion human cells. Each one of you consists of 10 trillion human cells. But even that number is totally dwarfed by the number of microbial cells that are associated with the human body. 

The number of microbes that are currently in and on your person is 10 times the number of human cells. We're talking about 100 trillion microbes. Now, I know what you're thinking, oh, look at all these zeros, fancy. Okay, well, I know that the math part isn't all that exciting, so I also like to show this visually to really drive home the point. Let's say that these circles represent the number of human cells per human. Now we're going to look at the number of microbial cells per human. It's not the same number, it's not twice as many, it's not four times as many. We're talking about 10 times as many microbial cells as human cells associated with each human on Earth. Again, in comparison, looking at this schematic. The total human population of Earth, the wee little seven billion, that's too small to see on this scale. 

The reason that I really like to drive home this point is that, I think it safe to say even though you can't see them by and large, our wee little microbes that are associated with us are bound to have huge effects on us. In fact, there are some debates that go on in philosophy about whether this makes us more microbe than human, but this is science night. We're sticking to science. We're not doing philosophy. Okay, so a little more about your 100 trillion microbes. First of all, where are they located? Most of them are located on the skin, nose, mouth, throat, and also in your gastrointestinal tract. I just have a few micrographs here showing examples of that. The microbes are colored artificially in orange here. Some are on the nasal epithelium, some attached to the small intestine. By far most of the microbes are found in the intestine. 

In particular, in the large intestine they can number just a ridiculous amount, about a 100 billion cells per gram. That's a very tiny amount and that's a lot of cells per gram. In addition to having so many microbial cells, there's a huge diversity in them. There's been over 1,000 different species of microbes that have been found so far to be associated with humans. Although, the typical human usually has about 160 species associated with them. All right, so before we move on again to some of the benefits of all these microbes that are associated with us, we've got to just go over a little bit of terminology first. I'm going to be using this term, microbiota. What exactly is that? This is simply the collection or community of different microorganisms that are regularly found in a particular environment. That can be any environment. It can be the ocean, it can be soil, it can be people, it can be a doorknob, anything. 

All right, so this is also sometimes referred to as microbiome. Sometimes these terms are used interchangeably. If I talk about the normal human microbiota, that's simply all of the microorganisms that are typically associated with the human body. Here's just another example of the diversity. Different microbes associated with the just with the tongue are colored in different colors here. Along with this term microbiome, you may have heard it in the news as far as the Human Microbiome Project. What exactly is that? Among other things, one of the goals is to sequence the DNA of the microbiome, all the microbes associated with multiple different humans. The human microbiome is estimated to contain over 150 times more DNA, or in other words genes, than the human genome. One of the big goals, why people are so interested in this again is, what exactly are these microbes doing for us, both in terms of contributing to our health, as well as possibly having effects on disease. One of the big goals of this is just to characterize all these microbes as a first step toward understanding how their interactions with us help us and harm us. 

In addition to this it's actually already known that the microbiota have many beneficial effects on humans. All right, so at this point you just may be thinking, well, that's great. I have 100 trillion microbes crawling all over me and I need to go home and shower immediately after Greg's fascinating talk. Rest assured, you've got absolutely no chance of gettin' rid of those puppies. But you don't have to worry about that because a lot of these microbes you want to have around. They do a lot of good things for you, all right. That may lead you to ask, if you're feeling skeptical about this, what did your microbiota ever do for you? Well, that's what we're going to talk about now. For starters, microbiota have huge benefits on our digestion. One of the big things that they do is make us nutrients such as vitamins. Intestinal bacteria actually produce certain vitamins that we need that are essential to our health. 

A big example of that is vitamin K. We would generally be undernourished for vitamin K if wasn't for the microbes producing these for us. Another example of that is vitamin B12, and also some of the other B vitamins that are just needed for the normal, happy, functioning of our human cells. Another big thing that microbes do for us is they help us digest and absorb nutrients. A few examples of that there's a bacteria called bacteroides. Bacteroides breaks down starch and other complex carbohydrates, a lot of different plant carbohydrates that we wouldn't otherwise necessarily be able to use as a food source. In addition to that, lactic acid bacteria, again, is closely related to the ones found in yogurt. Remember one of the things they were able to do is eat up sugars and turn them into other stuff. So they help break down sugars for us so that we can absorb the nutrients in them. Another big thing that our microbiota do for us is they stimulate development of certain human tissue. 

Without these microbes being present your own human tissue wouldn't be properly developed. A big example of this is certain intestinal lymph nodes. This is a big part of our immune system. It helps us respond properly to pathogens which are microbes that cause disease. Without having the microbiota around these immune tissues wouldn't develop properly and it would be harder for them to respond to diseases. All of these digestive benefits of microbiota have led to an interest in probiotics. What exactly are probiotics? When we talk about this we're talking about having people ingest live microbial cultures. The idea is that they'll exert a beneficial effect of some kind. An example of this you may have heard of, again. With yogurt you're eating live cultures of bacteria. 

So these lactic acid bacteria, as we just talked about, can have some benefits to digestion. One of these branches of probiotics that has been a particular hot topic of research lately is trying to use some of these microbes to treat certain diseases. An example of that is irritable bowel syndrome. It's possible that the particular microbial composition in people can effect whether they have this disease or not. However, some of the commercial products that are available right now, as far as probiotics, it's not always clear that they are effective at regulating digestion. The big example of this is the yogurt that the mom from Freaky Friday sells. Man, I can't believe I just made two Lindsay Lohan jokes in one talk. Okay, we've got to stick to the science here. That's no good. Dannon got in trouble about three years ago for kind of over stating the benefits of Activia. 

The bottom line is that Activia may help your digestion but you'd need to eat like a ridiculously high amount of it, more than anybody would ever want to. The bottom line on probiotics is there's undoubtedly some ability and potential there for them to able to help people, but there's a lot more research that's needed on this complex subject. All right, so regardless of the effects of the microbiota, again, it's very clear that they have a big effect on human health. Another area in which this has been seen that there's definitely some kind of link is with obesity. What's been seen in experiments with mice is that fat levels differ between normal, verses germfree. In other words, these are mice completely lacking microbes. They are lacking microbiota mice. You can see an example of that here. What's been found is that on a high-fat diet, if both of these guys are fed on a high-fat diet. The germfree mice are going to eat more but they're going to gain less weight. 

whereas the guys that have their microbiota, you can see, they're not doing so good. The interesting thing about this is that it's kind of thought that what your microbiota do, by virtue of the fact that they help you digest, is that they may help the mice extract more energy from their diet. If the mice are incorporating more energy into their bodies. That's why they're gaining more weight. What was also seen is a huge difference in the types of microbes that were associated with obese and lean mice. In particular, they differ in the proportions of two of the major groups of bacteria that are found in the intestine. What was found is that obese mice had way fewer of a big group called bacteroidetes. Then they had a lot more of a group called firmicutes. What was seen in lean mice is that the proportions of these two big groups of microbes was completely flipped. All right, so why are we talking about mice so much? Well, let's bring it back to humans. 

It's actually been seen that in obese and lean humans they also differ in their proportions in these same two major groups of intestinal bacteria. We can't really make people completely sterol of microbes, again. That's just a very difficult thing to do, and also we get into some kind of murky ethical areas. Again, they provide you with so many benefits that you probably don't want to be doing that to people. What they did to kind of monitor the effects of microbes in humans instead is they changed the diet of people. They took obese human subjects that were fed on a carb or fat restricted diet for a year, and they saw it that the proportion of each of the two big groups of microbes flipped. Again, with obese mice and people you see a lot fewer of the bacteroidetes and way more of the firmicutes. What was seen when they were put on this carb and fat restricted diet is that that proportion flipped, to more mirror what is seen in lean humans. There is much more of the bacteroidetes and way fewer of the firmicutes. It could be that those that are associated with obese populations may be more adept at absorbing fat and carbs. 

But we have to put a little caveat on this. That does not mean that the microbes themselves cause the weight difference. This isn't a cause and effect thing necessarily. But there is a definitely link there. The thing is that this is kind of a chicken or egg problem. It's not clear if the microbiota are leading to obesity or if obese people who have a fatty diet just happen to be eating things that these microbes prefer. Right? The bottom line, if you're trying to study this in a person, they have over 160 species doing different things. It's a complex interplay. That's another thing that the Human Microbiome Project wants to be working on. It's trying to figure out, even though we have this complex interacting, just what everything there is doing. 

But the bottom line is that some microbiota members are definitely more adept at nutrient absorption than others, and that's probably going to have an effect on our health.  To the final part of the talk, the death defying. This is perhaps the most important role of your 100 trillion microbial buddies. That fact of the matter is that these microbes don't just help with our digestion. They have this really key role. In fact, the microbes associated with our intestine, our respiratory system, our skin, they're constantly associating with, interacting with, the outside world. This actually puts them at the forefront of a microscopic war. Essentially they are our first line of defense against the invading bad guys which are microbial pathogens. As I mentioned, pathogens are microbes that want nothing more than to breach human defenses and cause disease. Again, those are the ones, that's our less than 1% that you always hear about in the news. 

That brings me back to our antibacterial soap. You know, given all of these benefits of the microbes, it may be kind of a novel approach to warfare to use this nuclear option of antibacterial compounds. Because you're going to be not just killing the bad ones, but all of these good ones that are associated with you. Thankfully, your microbiota are pretty resilient. If you wash hands, within tens of seconds, or even up to a couple of minutes, they're already bouncing back. They're pretty good at hanging around. You don't have to worry about that too much. You know, the other thing I have to say about this before I get off my-- No, I can't do it. I was going to say soap box, but that's just too bad of a pun. You know, soap is really important, right, to the history of humans. 

It really actually increased life expectancy. It's really good for hygiene. It makes you clean. It smells delicious. Everybody likes it. But the thing is, it's really good at cleaning you. You don't really need these extra chemicals that destroy other bacteria in them. Really, soap by itself does a perfectly fine job. All right, so one of the other problems with soap that researchers have started to look at is perhaps this is taking away the job that your immune system normally does. The question that people are starting to ask is, is there such a thing as being too clean? This is called, more formally, the hygiene hypothesis. 

What the hygiene hypothesis is is that this kind of modern obsession with eradicating all germs has backfired. Essentially, eliminating so many germs that you leave your immune system all dressed up with nothing to do. The idea is that the immune system is super hyper-active. It's kind of bored. It's looking for trouble. It's kind of turning your immune system into a hoodlum, kind of a rabble-rouser. Nobody wants that. But the idea is that since your immune system has so much time on its hands this could lead to more cases of immune-related diseases, such as allergies, asthma, arthritis. These are things that are where the immune system is in one way or another involved in attacking its own body. When I say too clean, what I'm talking about is, again, we get rid of the pathogens, but also we are getting rid of some of our microbiota. 

What this also could mean is that your immune system is simply encountering less microbes. Again, it's designed to deal with a lot of invading microbes. It's designed to deal with this kind of thing. So not being exposed to it could mean less education for your immune system. In addition, if you knock the microbiota down too much, that could lead to the immune system not being as on alert as it could be. We're going to talk about what that means in just a minute or two. I don't know. Bottom line, my two cents are kind of let your kids play in the mud. Just hose them off after. Let them have a little exposure to this stuff, but don't let it get out of control. 

Back to what your microbes do to help defend you. Again, we've got to put this is a little context. First of all, the arena for our microscopic battle. We are talking about 28 feet of intestinal goodness. This is where a lot of these interactions are going on. Again, also your are microbes associated with the skin, the respiratory tract, things that are associated with the outside. All right, so what are some of the things that microbes do to help protect us from disease? Well, I'm going to be using this simplified schematic here. My little smiley guys are the orange microbes here, and then they're sitting on top of our intestinal cells, our human cells. One of the first things that they do is they essentially secure the perimeter for us. These guys, by virtue of the fact that they're already there, they're in our intestine, they're on our skin, they have a foothold and they're good at staying there. 

Essentially, this makes our bad pathogens, our disease causing microbes-- It's kind of like we're playing musically chairs and the pathogens are late to the party. These guys are already there. They're kind of blocking the entrance. You can kind of think of them as the bouncer of the human body. They're blocking the bad guys from getting in. Another big thing that our microbes do is a trade embargo. What our microbes do is they compete for nutrients with the pathogens. That makes it a lot harder the pathogens to get their own food. Another major role of our microbiota is that just like in food, the examples we talked about in helping to prevent food from spoiling, our microbes produce acid and other compounds that can harm pathogens. This can help prevent the growth of the microbes even if they get into the human body. 

This process is known as microbial antagonism. This is especially common on the skin and mucous membranes. There's actually a little more acidic level of acid on your skin and mucous membranes. Then one other big roles that I alluded to, our microbes kind of help stimulate our immune system, keeping it on alert for potential invaders. Again, by virtue of the fact that we have these microbes here, the immune system is sensing the fact that there are microbes, foreign organisms, around. And so our immune system consists of both chemicals, kind of poisons, called anti-microbial compounds, and also immune cells that are able to deal with various invading problems. If our microbiota are keeping these guys on a level of alert already, they're that much more ready to spring into action if some of the pathogens happen to invade our body. Okay, so we're going to talk about one of these in just a little more example. Probably the most famous member of the human microbiota that you've probably heard of is E.coli. Before we talk about what E.coli does I've got to ask you a question. 

When I say E.coli, what do you think of? Anybody. [inaudible] Yup, that's the big one. Yup, diseases, poop. What else? All right, you get the idea. Most people think of some variation on this, right? [laughter] Usually you eat some bad food at kind of a shady restaurant perhaps, and then you find that you have a sudden and unmistakable necessity to place one end or the other of your person upon this object here. Sometimes people find themselves in the unenviable position of having to chose which one of their two ends that gets priority seating on this object. [laughter] Yeah, it's not a good thing. Bottom line, most people when they think of E.coli, think of disease, food poisoning and that kind of thing. But actually, just like our misrepresentation of microbes in the news, E.coli isn't even in the top five causes of food borne illness according to the Center for Disease Control. It is an important cause, but it isn't even in the top five. 

The fact of the matter is of most types of E.coli, a majority do not actually cause disease. In fact, E.coli is a very common member of the human intestinal microbiota. In fact, I can almost guarantee that this guy's hanging out in your intestines right now. Yet, I don't see a ton of you making a beeline for the bathroom. Okay, I'm always a little nervous somebody's going to get up and go when I say that, but anyway-- The reason for this is because E.coli is actually one of these microbiota members that provides us with a lot of benefits. In fact, E.coli provides us with so many benefits that from now on when you think of E.coli I don't want you to think about the toilet. I want you to think-- E.coli is the hero of our story. You guys are starting to be like, man, this Hunger Games thing is a rip-off. There's like-- You just use that incredible catchy title to get us here. You're not even going to talk about it. 

Well, guess what? I am. Okay, so what actually does E.coli do that's so great? Here's what E.coli does that's so great. This dude's really got your back. Remember when we talked about our nutrient production. E.coli is one of the ones that makes us vitamins, such as vitamin K and the B vitamins. It's also one the microbes that prevents bad microbes from attaching and invading. In fact, E.coli is pretty good at getting actively rid of bad microbes by producing a substance called bacteriocins. What exactly are bacteriocins? Katniss, meet bow and arrow. That's what bacteriocins are. That's our hero's weapon. 

Bacteriocins are proteins that kill other closely related bacteria by lysing them. In other words, they bust open the closely related bacteria and make them explode. Some of these bacteria are related to E.coli, and the reason that that's relevant is because they are causes of food poisoning. Some of the examples of bacteria that these bacteriocins target are things like salmonella. Right? And also actually E.coli, because remember, although not all kinds of E.coli are bad, there are some kinds of E.coli that are bad. Some kinds of E.coli do cause disease. I guess that makes this Evil Katniss? [laughter] No? I think I'm kind of reaching the end of the usefulness of my Hunger Games metaphor here, but anyway-- There's actually a lot of interest in using these substances, like bacteriocins and other anti-microbials that microbes themselves produce, in order to treat diseases. In addition, this is especially important, because as you may have heard in the news, about bacteria that infect us becoming resistant to our treatments, such as antibiotics. This could be used as a potential alternative treatment for bacteria that are resistant to antibiotics. All right, so in sum, if you remember one thing from tonight's talk, I hope you remember that microbes are not so bad. 

They do a lot of good stuff for us. They help us make delicious food, they provide us with nutrients. And in addition, they're one of our most important and first lines of defense against bad microbes. In addition, we could possibly harness their abilities to target other microbial pathogens as a way to help us treat diseases. So with that, I would like to say a few thanks, particularly to the Department of Biological Sciences at UW-Parkside where I work. It's a great place to work. If you haven't been there, as Tom said, it's kind of between Racine and Kenosha. I'm told, and I don't know that it's true, that it actually has the second highest acreage of any UW school behind Madison. There's a lot of gorgeous trails, hiking and running, there. Also biking. 

And also I'd like to thank Tom and all the people associated with putting together science night. And I'd like to thank you guys for being here. [applause]