What do the microbes in your mouth do?

    • Topic: Human Biology

    • Location: Hall of Human Life

    Your digestive tract (mouth, stomach, intestines, etc.) is host to an entire ecosystem of microbes, including bacteria, fungi, and viruses. While much of this ecosystem, or microbiome, is common to all people, each individual’s microbiome is unique. We are interested in learning more about the microbes that live in the mouth to better understand how to help people with digestive issues.

    In this study, people will be asked to donate saliva by spitting or drooling into a small test tube approximately four times, to provide a saliva sample large enough to be analyzed. We will grow the microbes in each sample in our lab so that we can determine which microbes are present and what enzymes (organic molecules that support important chemical reactions) they produce.

    We are particularly interested in finding enzymes that break down gluten. Gluten is a set of proteins found in plants like wheat, which is used in breads, cereals, and many other foods. We expect that all people have microbes in their mouth that make enzymes that aid in the digestion of gluten, but that the levels of these enzymes vary between individuals. Furthermore, different microbes may use different enzymes to break down gluten. Differences in microbes and the enzymes they produce may be related to whether people have problems digesting gluten.

    We hope that our results will provide the foundation for developing new treatments to help people with celiac disease and related disorders.

    This research is conducted at the Museum of Science, Boston, by Eva Helmerhorst. This project is funded in part by the National Institute of Allergy and Infectious Diseases (NIAID).

        » Dr. Eva Helmerhorst

    Activities to Try in the Hall of Human Life

    You Are Not Alone

    Stand in front of the Body Mirror in the Organisms environment to learn more about the human microbiome. The Body Mirror will project some of the most common and important microbes found in humans on an outline of your own body.

    The microbes shown are just a fraction of the diverse ecology of your body. Your microbiome contains hundreds of different species. Taken together, these microbes amount to hundreds of trillions of cells. In fact, your microbiome makes up a larger portion of the cells in your body than your own cells do.

    Activities to Try at Home

    Gluten Revealed

    Gluten is what permits dough to rise. It is elastic, which makes dough stretchy. The yeast added to dough produces carbon dioxide, which inflates the stretchy dough like a balloon.

    Mix together flour and water to make a small ball of dough. You should use about twice as much flour as water. Knead the dough until it is firm.

    Flour is made of gluten and starch. Starch, but not gluten, dissolves in warm water. To remove the starch and reveal the gluten, hold your ball of dough under warm running water. The water will become cloudy as it fills with starch. Keep rinsing the ball until the water runs clear.

    Explore your gluten. See how it stretches. These are the proteins that make bread chewy! Try making your dough with different types of flour, such as whole wheat or cake flour. Some types contain more gluten than others. How do you think using different types of flour will affect the ball of gluten you are left with?

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