Human Microbiome

by Vincent Racaniello, PhD

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    00:01 Hello and welcome to Bacteria. We are going to dive a little bit deeper into how bacteria cause disease and after you've watched this video, you will understand the extent, origin and functions of the human microbiome. You will appreciate the ways that bacteria enter and spread in their hosts. You will be familiar with the different types of bacterial toxins and their activities and you will know the mechanisms of action of members of the different classes of antimicrobials and how resistance emerges.

    00:37 Before we talk about bacteria that cause disease, it's very important to first discuss the human microbiome, all of the microbes that live in and on us. We are home to trillions of microbes, trillions, and that's what we call the microbiome and it is a composition of all the microbes that are everywhere in us and on top of us. A human body is only 25% human cells. Now look, you can see me, you think you're looking at just human cells.

    01:13 75% of what you see here are bacteria, very, very little human cells, bacteria, fungi and archaea. It’s amazing. Wherever the human body is exposed to the outside world, there's a microbial community, the mouth, the lungs, the G.I. tract, the urogenital tract, the skin and probably other places we haven't even found it yet. This microbiome is just beginning to be unraveled in terms of what it does for us. It certainly helps us to extract energy and nutrients from the food we eat, but it also appears to inhibit the growth of pathogens, not only in us, but on our skin. The microbes on our skin produce antimicrobial compounds that protect us, it is remarkable. There is probably much more that the microbiome does, for example, recently it's been shown in animals that the microbiome helps their immune system to develop, it is really, really remarkable. In the coming years we will be able to sort all of this out, but it's quite clear from the very early days of our existence when we were first born, our microbiome forms and it has a huge impact on our health.

    02:39 Microbes contribute an extra 2 million genes to the 20,000 or so genes that our human genome encodes. 99% of our genes are bacterial, isn't it remarkable? Our microbiome weighs two and a half pounds, that is weight you will never be able to get rid of, you can try and lose some of your body fat, but that two and a half pounds of microbiome needs to stay with you, otherwise you are going to be very unhealthy, and don't forget the viruses, all those bacteria and fungi and archaea in us, they also are accompanied by their viruses, in fact viruses outnumber bacteria by about 5 to 1 in us and it's quite clear that they have major roles in regulating the microbiome.

    03:26 The volume of the microbiome is about 3 pints. The next time you drink 3 pints of beers, I want you to remember you’ve just drunk the volume of your microbiome. It’s my way of getting you to remember what I'm telling you here. Now where do you get this microbiome? There are many ways. While you are developing in utero, you are bathed in amniotic fluid provided by your mother, and of course it's going into your mouth and on your skin, and it's got bacteria and viruses in it, so that’s your first encounter. You are acquiring your microbiome in utero. Then as you are born, you acquire more of your microbiome. During birth, if you so happen to have been born by passage through the birth canal, you will start to acquire the bacteria that are present along that canal, not just in your mouth but on your skin. People who are born by cesarean section, they don't go through the birth canal, of course, they come out through an opening in the skin, produced by surgical manipulation, they have a very different skin microbiome from children who were born vaginally. So it's probably better to be born through the normal routes, you acquire probably a more beneficial microbiome, but of course in some cases it's not possible for health reasons. You also acquire a good amount of your microbiome from your mother. Your mother is one of the first to hug and kiss you, and she continues to do so, hopefully, for the rest of your life, and your father also contributes, and any caregivers who may come into your home, they are all contributing to your microbiome. Breast milk is a very important contributor to your gut microbiome, again breast-feeding is not done by everyone, but it has been shown in many studies to be better indicators of subsequent health. You also acquire microbiome from the soil that you may touch. You should let your kids play in the soil, it is probably good for them to help acquire their microbione from the water that you wash yourself in and drink, from the foods that you eat, and any people or pets or plants that you encounter early on in your life. The early years are formative years and then you acquire a relatively stable microbiome that is very similar to that of your family, and only when your health changes, or if you move or change your diet, do you change your microbiome.

    About the Lecture

    The lecture Human Microbiome by Vincent Racaniello, PhD is from the course Bacteria.

    Included Quiz Questions

    1. Bacterial cells
    2. Fungal cells
    3. Epithelial cells
    4. Protozoal cells
    5. Archaeal cells
    1. Aids in extraction of nutrients from food consumed
    2. Enhances cell to cell signaling
    3. Aids in oxidative phosphorylation
    4. Enhances anaerobic digestion
    5. Produces toxins that prevent human cell overgrowth
    1. Being born vaginally versus C-section
    2. Changes in amniotic fluid
    3. Differences in water and soil
    4. Early physical contact
    5. Differences in breast milk
    1. Genetic makeup
    2. Composition of drinking water
    3. Soil composition
    4. Differences in diet
    5. Differences in local plants and animals

    Author of lecture Human Microbiome

     Vincent Racaniello, PhD

    Vincent Racaniello, PhD

    Customer reviews

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    It's a amazing introduction. I'm expected about this course!!!
    By Giovanni P. on 04. January 2019 for Human Microbiome

    I think that this course is a incredible tool for medical students. I belive that it's important the Microbiology for doctors and it's great that we have access at it's information

    Nice introduction to a complex subject
    By Mohsin K. on 07. December 2018 for Human Microbiome

    5/5 because of the simplified explanation of the human microbiome. I like the approach used because it sets the stage for acquiring important high yield information later into the subject.

    Thank you.
    By John Kenneth B. on 25. August 2018 for Human Microbiome

    A very good lecturer of Microbiology. Thank you and I am looking forward in learning more.

    He is a very good lecturer and great facilitator of microbiology.
    By Alexander W. on 17. August 2017 for Human Microbiome

    He is a very good lecturer and great facilitator of microbiology.