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Gutopia: A Microbial Paradise

The development of the microscope in the 17th century magnified our awareness of a microbial universe previously invisible to the naked eye. Anton van Leeuwenhoek, a Dutch textile draper and science hobbyist, was one of the first individuals to glance into the microbial looking glass and identify unicellular organisms (so-called animalcules) such as protozoa and bacteria [1]. His colleague, Robert Hooke, went on to publish the seminal text, Micrographia, which described his observations of microfungi [2]. Two centuries later, Louis Pasteur validated the role of microbes in fermentation. However, Pasteur also gave weight to Ignaz Semmelweis’ controversial germ theory of disease stating that microbes have the capacity to cause pathological effects on our human health [3].

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Early microbial drawings by Anton Van Leeuwenhoek [Photo Credit: Yale University Press]

These early studies in microbiology have provided significant insight on the human-microbe interaction characterized by either mutually beneficial or lethal outcomes. The duality of microbial behavior has dramatically impacted our perception of these microorganisms. Our cultural germophobia often precludes our ability to recognize the naturally transformative and symbiotic properties of microbes from the fermentation of grape juice into wine to their invaluable role in human digestion.

Michael Pollan, author of Cooked, explores a myriad of cooking traditions including those that directly involve the action of microbes such as bacteria and yeast. In his depiction of ancient sourdough recipes, he lists four ingredients: whole grain flour, water, salt, and the repertoire of microbes in the air [4]. The microbes catalyze slow-fermentation reactions (taking up to 24 hours) that leaven the bread while transforming molecules into digestible nutrients for us to absorb.

Whether we can stomach it or not, we all possess unique microbial signatures that are composed of trillions of microorganisms living both inside our bodies and on the surface of our skin [5]. These microbial communities, referred to as the human microbiome, cohabitate in our various mucosal, gastrointestinal, and epidermal surfaces. Symbiotic microbes are tolerated by our immune system and work collaboratively with our own bodies to digest the foods that we eat at the molecular level.

Our evolutionary history with bacteria is fueled by the currency of nutrition. In other words, our diet has a significant impact on the composition of our gut microbiota. Food consumption habits can either encourage the intestinal bloom of beneficial bacteria or opportunistic, disease-causing bacteria. Certain foods contain vital prebiotic molecules that encourage the expansion of beneficial bacterial species in the gut. High fiber foods including whole grains (brown rice, oats), vegetables (broccoli, peas) and legumes (lentils, black beans) contain an invaluable source of metabolic substrates that are converted into short-chain fatty acids by bacteria [6]. These short-chain fatty acids, such as butyrate, help to propagate microflora such as Bifidobacterium and Lactobacillus and maintain gastrointestinal tissue health [7].

If we were to design a perfect microbial habitat–a Gutopia, if you will, it would be a homeostatic organ city of diverse symbiotic microbiota that is rich in fiber economy and free of any harmful pollutants. However, our dietary choices can tip the balance of this intestinal paradise and create a dystopic environment suitable for the expansion of pathogenic microbes.

Contemporary eating habits that are characteristically high in fat and carbohydrates are responsible for the emergence of modern diseases such as diabetes, colorectal cancer, and inflammatory bowel diseases [8-11]. Recent studies suggest that compositional changes in the intestinal microbiome can encourage the bloom of disease-causing microflora. The dramatic alteration of today’s eating behavior introduces gastrointestinal disturbances or challenges that our bodies and microbial counterparts have not evolved to accommodate. For example, a study investigating the consumption of different dietary fats in immunocompromised IL-10/ mice identified the expansion of B. wadsworthia; a gram-negative, sulfur-reducing species of bacteria flourished in mice fed a diet high in saturated fat , but not in low-fat or polyunsaturated fat diets [12-13]. The bloom of B. wadsworthia was attributed to the unregulated production of a bile salt known as taurocholic acid brought about by the overconsumption of saturated fat.

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Imbalanced dietary intake and overconsumption of foods high in saturated fats can impact the ecology of gut microbiota [Illustration by Grace Danico]

Taurocholic acid is an important source of sulfur that can stimulate the growth and maintenance of the pathogenic B. wadsworthia in these mice. The presence of this bacterium activates murine proinflammatory immune defense mechanisms that compromise the permeability of gut mucosal tissue causing intestinal inflammation. This pathogenic etiology of gut inflammation is implicated in the onset of Crohn’s disease and ulcerative colitis [12-13].

Much like any city there are complications that arise, which can tip the balance between utopic and dystopic environments. In the case of our gut health, we should imagine ourselves as landscape architects cultivating the balanced ecology of our microbiome. If we feed our intestinal gardens with the right balance of foods we can foster the growth of symbiotic bacteria while discouraging the bloom of pestilent, pathogenic microbial weeds.

The human microbiome not only affects our gut health but can have some profound effects on our behavior and brain function. Dr. Elaine Hsiao, Assistant Professor in the Department of Integrative Biology and Physiology at UCLA, investigates the interplay between our commensal microbes and their role in neurological development and function. Her work has linked the perturbations in gut microbiota with the onset of neurological disorders such as autism [14].

As we continue to study the ecology and diversity of microbes living within and around us, we are faced with many fundamental challenges in testing the dynamics of these microbial communities. From a clinical perspective, physicians and researchers alike have utilized human fecal samples to identify unique microbial gut profiles in their patients. These samples serve as powerful investigative tools in our pursuit to understand how certain commensal microbes can cause or serve as diagnostic readouts. The power of the sequencing technology used to characterize microbes in stool samples (16s RNA sequencing) comes from its level of coverage-the ability to identify the majority of bacteria in a sample. However, sequencing depth-the resolution at which a species can be identified remains challenging. Additionally, many microbial species have been challenging to culture in vitro, making it difficult for researchers to repeatedly perform experiments in a laboratory setting and gain a deeper mechanistic understanding of microbial behavior and ecology.

Dr. Rachel Dutton, Assistant Professor in the Division of Biological Sciences at UCSD, addresses some of these technological limitations by studying the establishment and maintenance of microbial communities in different types of cheeses. With this model, her lab can investigate the interactions of different types of microbes to better understand them as ecological systems [15-16].

Science & Food is honored to host Elaine Hsiao and Rachel Dutton for the 2016 UCLA Science & Food public lecture series to elaborate on their findings.  They will be accompanied by Sander Katz, author of Wild Fermentation, who will discuss the transformative properties of microbes in the production of foods like sauerkraut.

Join us on Wednesday, May 11th at 7PM in Schoenberg Hall at UCLA for “Microbes: From Your Food to Your Brain” to learn more about the intriguing world of microbes!

References cited

  1. Gest H. “The discovery of microorganisms by Robert Hooke and Antoni Van Leeuwenhoek, fellows of the Royal Society”. Notes Rec R Soc Lond. 5 (2004). 187-201.
  2. Hooke R. “Micrographia” Jo. Martyn & Ja. Allestry (1665).
  3. “The History of the Germ Theory” The British Medical Journal. 1 (1888).
  4. Pollan M. Cooked: A Natural History of Transformation. Penguin Books. (2013).
  5. Abbott A. “Scientist bust myth that our bodies have more bacteria than human cellsNature. (2016).
  6. Leone V, Chang EB, Devkota SD. “Diet, microbes, and host genetics: the perfect storm in inflammatory bowel disease” J. Gastroenterol 48 (2013). 315-321.
  7. Sartor RB,.“Microbial influences in inflammatory bowel disease: role in pathogenesis and clinical implications” Elsevier (2004). 138-162.
  8. Hotamisligil, GS. “Inflammation and metabolic disorders” Nature. 444 (2006). 860-867.
  9. Parkin DM, Bray F, Ferlay J, et al. “Global cancer statistics” CA Cancer J Clin. 55. (2005). 74-108.
  10. Loftus EV Jr. “Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences” Gastroenterology 126. (2004). 1504-1517.
  11. Molodecky NA, Soon IS, Rabi EM, et al. “Increasing incidence and prevalence of the inflammatory bowel diseases with time, based on systemic review” Gastroenterology 142. (2012). 46-54.
  12. Devkota SD, Wang Y, Musch MW, et al. “Dietary-fat-induced taurocholic acid promotes pathobiont expansion and colitis in Il10-/- mice” Nature. 487 (2012). 104-108.
  13. Devkota SD, Chang EB. “Diet-induced expansion of pathobionts in experimental colitis” Gut Microbes. 4:2 (2013). 172-174.
  14. Hsiao E.Y., “Gastrointestinal issues in autism spectrum disorder”, Harv Rev Psychiatry, 22 (2014). 104-111.
  15. Wolfe BE, Dutton RJ. “Fermented Foods as Experimentally Tractable Microbial Ecosystems” Cell. 161(1) (2015). 49-55.
  16. Wolfe BE, Button JE, Sanarelli M, Dutton RJ. “Cheese rind communities provide tractable systems for in situ and in vitro studies of microbial diversity” Cell. 158 (2014). 422-433.

Anthony MartinAbout the author: Anthony Martin received his Ph.D. in Genetic, Cellular and Molecular Biology at USC and is self-publishing a cookbook of his favorite Filipino dishes.

Read more by Anthony Martin


Fermentation Revival & Mind-Altering Microbes

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Sandor Katz and Dr. Elaine Hsiao will be joining us at our next 2016 public lecture, Microbes: From Your Food to Your Brain. Get to know them beforehand, as Sandor Katz talks about his book, The Art of Fermentation, on NPR: Fresh Air and Dr. Hsiao shares her fascination with the microbiome at a TedxCaltech talk.
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Sandor Katz

Sandor Katz, a self-proclaimed fermentation revivalist, became hooked on fermentation with his first homemade batch of sauerkraut, earning him the nickname “Sandorkraut”. As an AIDS survivor, he considers fermented foods an important part of his health and well-being. His 2003 book, Wild Fermentation, was lauded by Newsweek as the “fermentation bible”, and his 2012 book, The Art of Fermentation, received a James Beard award and was a finalist at the International Association of Culinary Professionals. In 2014, Katz received the Craig Claiborne Lifetime Achievement Award from the Southern Foodways Alliance.

See Sandor Katz May 11, 2016 at “Microbes: From Your Food to Your Brain”

Sandor Katz

What hooked you on cooking?
I’ve always loved eating, and my parents both cooked and we were always expected to help in the kitchen. I got especially interested in cooking from scratch, and understanding and experiencing how the raw products of agriculture are transformed into the foods we love to eat.
The coolest example of science in your food?
Our food is all biology and chemistry. Of course, I am most tuned into the biological processes, though at a certain level they break down to chemistry. One question that I have thought a lot about is: Why is fermentation practiced everywhere? I do not know this to be absolute fact, but I have been unable to find any counter-example. And the reason that we now understand is that all of the plants and animal products that make up our food are populated by elaborate microbial communities. Microbial transformation of our food is an inevitability and the question is how do we deal with that fact.
The food you find most fascinating?
I’m endlessly fascinated by kefir, a fermented milk, or rather by the culture that produces it, undulating rubbery masses known as kefir grains. These symbiotic communities of bacteria and yeast (SCOBIES) are incredibly complex, with more than 30 distinct organisms that have been identified.
What scientific concept–food related or otherwise–do you find most fascinating?
Co-evolution. How we have evolved with plants and microorganisms and how they have influenced what we are and how we have influenced what they are, and how each of these organisms has influenced the others. All the foods that’ve been interested in come about as a result of these co-evolutionary relationships.
Your best example of a food that is better because of science?
Certainly fermentation is better understood because of science, and it is possible thanks to science to replicate particular ferments in environments other than those in which they emerged as spontaneous outcomes. However, it is important to note that science has had negative effects on fermentation practices as well as positive ones. The presumption that large undefined communities of organisms are dangerous has led to the replacement of traditional starter cultures with pure culture starters that cannot easily be perpetuated, thus diminishing the ability of home, village, or small-scale producers to perpetuate cultures and thereby breeding dependence on starters purchased from a lab for each batch.
How do you think science will impact your world of food in the next 5 years?
I’m very excited by all the new findings in microbiology, especially our emerging understandings of microbial communities in different environments and their complex interactions. My hope is that our growing understandings of the functional importance of microbial communities will help us move beyond the war on bacteria, and embrace bacteria as our ancestors, allies, and greatest protection.
One kitchen tool you could not live without?
My crocks! Vessels are the most basic of kitchen tools.
Five things most likely to be found in your fridge?
Milk, yogurt, starter cultures, beer, miso. Kraut and kimchi might be in the fridge, or might be on the counter.
Your all-time favorite ingredient? Favorite cookbook?
Brussels sprouts, along with almost any cruciferous vegetable. They are so delicious and versatile! I like to check out cookbooks and explore recipes from diverse sources, but Joy of Cooking is my enduring go-to.
Your standard breakfast?
I love to use my sourdough starter to make savory vegetable sourdough pancakes, incorporating almost any vegetables, leftover grains if I have them, and cheese, topped off with fried eggs and yogurt-hot sauce.

Science & Food UCLA 2016 Public Lecture Series

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The 2016 UCLA Science & Food public lecture series is here!

General admission tickets are available for $25 from the UCLA Central Ticket Office (CTO) . Tickets can be purchased from the UCLA CTO over the phone or in person and will not include additional fees or surcharges. The UCLA CTO is located on-campus and is open Monday–Friday, 10am –4pm. A UCLA CTO representative can be reached during these hours at 310-825-2101. Tickets can also be purchased online from Ticketmaster for $25 plus additional fees. A limited number of $5 student tickets are available to current UCLA students. These must be purchased in person at the UCLA CTO with a valid Bruin Card.


2016ImpactofWhatWeEat

The Impact of What We Eat: From Science & Technology, to Eating Local
Chef Daniel Patterson, Dr. Paul B. Thompson, & Dr. Kent Kirshenbaum

Tuesday, March 8, 2016 at 7:00pm
Schoenberg Hall, UCLA

 


2016Microbes

Microbes: From Your Food to Your Brain
Sandor Katz, Dr. Rachel Dutton, & Dr. Elaine Hsiao

Wednesday, May 11, 2016 at 7:00pm
Schoenberg Hall, UCLA

 


2016ZeroFoodprint

Curbing Carbon Emissions in Dining: A Conversation with Zero Foodprint
Chris Ying, Peter Freed, & Chef Anthony Myint

Thursday, May 19, 2016 at 7:00pm
Schoenberg Hall, UCLA