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1. Bacteria in the ecology of the human body • Guiding questions: • Why do we care about microbes in the human body? • How is the human microbiome like an ecosystem? • Why is understanding the human microbiome as an ecosystem helpful to our health? Picture source: http://healthylifestylealternatives.com/archives/tag/healthy-eating GK-12 Global Watersheds Program, Brenda Gail Bergman, 2013 1

2. Source: photo-dictionary.com What are bacteria? Are they in your body right now?

3. What could microbiome mean? What kinds of microbes are in humans? 3

4. All groups: • What role do bacteria play in your body? • About how many species of bacteria have been identified as living in the human body? • Group 1: • c. What percentage of all the cells in your body are non-human microbial cells? • d. For every 100 pounds of your body weight, approximately how many pounds are microbial cells? • Group 2: • e. The human genome has about 22,000 protein-coding genes . Given this, how many protein-coding genes do you think microbes in the human bodyhave? 4

5. Answers • More than 10,000 microbial species have been identified as living in human bodies thus far. • Microbial cells outnumber human cells in a human body 10:1! • Microbes account for only 1-3% of human body weight. • The microbiome contributes 8 million protein-coding genes. • http://commonfund.nih.gov/hmp/overview.aspx 5

6. Group 1: • Microbial cells outnumber human cells in a human body 10:1! • Recalculate the percentage of all the cells in your body that are non-human microbial cells. • b. Yet these microbes account for only 1-3% of human body weight. For every 100 pounds of body weight, how many pounds are microbes? • What does this imply in terms of the weight of microbial cells compared to that of human cells? • Group 2: • Microbes that occur in the human body have 8 million protein-coding genes, while the human genome has 22,000. • d. What percentage of potential protein-coding genes in • human bodies are from the microbiome? • Microbes in the human body contribute how many times • more of this vital genetic material than do humans? 6

7. Summary of what we’ve learned about bacteria in our bodies: • More than 10,000 microbial species have been identified as living in human bodies thus far. • Approximately 91% of the cells in our bodies are non-human microbial cells • The microbiome contributes 99.7% of the genetic material that encodes protein in our bodies. How would you summarize the main point of these statements in one sentence? 7

8. source: Scientific American • What do scientists mean when they refer to the body as an ecosystem? 8

9. Ecosystem http://www.chesapeakebay.net/discover/bayecosystem What is an ecosystem? 9

10. Are each of the members surviving independently? Organisms in a terrestrial ecosystem. Arrows connect prey to consumer. Colored dots indicate colors in the triangle at the upper right. source: http://wwwrcamnl.wr.usgs.gov Principle of interdependence 10

11. Principle of interdependence in our bodies Bacteria in human guts are similar to members of an ecosystem. They have specific nutrient requirements and have a complex dependence on one-another. This is why affecting one group can affect another http://scitechdaily.com/hmp-maps-the-healthy-human-microbiome/ 11

12. Extremely simplified food web What do living organisms use carbon for? How does carbon get from a plant into an animal, or from one animal into another? Principle of energy flow Source: The Great Lakes: An Environmental Atlas and Resource Book 12

13. Principle of ecological cycles http://www.eea.europa.eu/ • Are these nutrients staying in one place? • Are they staying in one form (electron state)? 13

14. Review of the ecological principles we have discussed • (note that these are only a subset): • An ecosystem is a network of interactions between organisms and their environment • Principle of interdependence: members ofecosystems are interdependent • Principle of energy flow: energy flows through the system. • Principle of ecological cycles: resources are exchanged in continual cycles. As part of this, nutrients move through the ecosystem and are changed into different forms. 14

15. General functions of bacteria in the human body 1. Digestive system Source: Society for microbiology Source: University of Maryland Medical Center 15

16. http://www.eea.europa.eu/ • What is transforming the organic matter into ammonium? • What is transforming the N2 gas into NO2? Principle of ecological cycles applied to the human microbiome: Microbes process B and K vitamins into forms usable by humans. 16

17. Where are bacteria on this food web? • With respect to food, what is another important role that bacteria could play for animals? Source: learnaboutfoodwebs.blogspot.com  17

18. General functions of bacteria in the human body 2. Immune system • What is the relationship between bacteria and disease? Source: University of Maryland Medical Center 18

19. Pakistan • Why might some kids have less bacteria than others? http://wondersofpakistan.wordpress.com/ Sweden http://yourlivingcity.com/ 19

20. source: http://wwwrcamnl.wr.usgs.gov • Bacteria can train our immune system to recognize and destroy pathogens, especially in early childhood. Principle of interdependence Source: University of Maryland Medical Center 20

21. Some functions of helpful bacteria to our immune system: • train our immune system to recognize and destroy pathogens. • decrease cancer-causing (carcinogenic) activity • protect against harmful bacteria • produce some antibiotics • reduce respiratory infections, like the common cold 21

22. General functions of bacteria in the human body 3. Nervous system Have you ever noticed your moods changing based on what you eat? What foods affect your moods? Why could this be? source: histologyolm.stevegallik.org 22

23. What is ‘your second brain’? Some functions of bacteria in our nervous system: affect human and animal psychology, particularly levels of anxiety 23

24. Medical ecology Many microorganisms in our bodies are critical for our lives Goal: Promote an internal environment that enables helpful bacteria to thrive and outcompete unhelpful bacteria 24 www.quora.com 

25. Solution for the antibiotic crisis? Source lolalollipop.com “Antibiotics are losing their effectiveness at a rate that is both alarming and irreversible... Bacteria are adapting and finding ways to survive the effects of antibiotics, ultimately becoming resistant so they no longer work.” –Sally Davies, PhD

26. Quorum sensing Bacteria can alter their behavior through chemical interactions. Use chemicals as cooperative signals, cues, and chemical manipulations that affect inter and intra species behavior http://www.bmglabtech.com/application-notes/luminescence/quorum-sensing-199.cfm

27. Some health conditions that have been found to be directly related to the balance of bacteria in the human body: • obesity, • type 1 diabetes, • childhood asthma, • inflammatory bowel disease, • colorectal cancer, • cardiovascular disease, • human immunodeficiency, • anxiety, • respiratory infections. • Janoff, Edward N., Claire Gustafson, and Daniel Frank. "The world within: living with our microbial guests and guides." Translational Research (2012). http://www.sciencemag.org/content/326/5960/1694.abstract 27

28. 1. Has your doctor mentioned the issue of balancing their bacteria as a possible remedy for health concerns in your family? • 2. Have you taken antibiotics over the past 5 years? • 3. Does anyone in your family eat certain foods (vegetables, potato chips, sugar, yogurt) much more than other members of your family? • 4. Does the person with a different diet get stressed or sick more or less often than the rest of you? • 5. Look back on your answers from the beginning of class regarding the role of bacteria in your bodies. Did you think that bacteria are mostly harmful? 28

29. http://wenchwisdom.blogspot.com/2012/06/this-just-in-and-awesome-tending-human.htmlhttp://wenchwisdom.blogspot.com/2012/06/this-just-in-and-awesome-tending-human.html 29