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Our Microscopic World

Updated: Jun 7, 2021

As a researcher interested in the concepts of host ecology and evolution, Northwestern's anthropologist Katherine Amato explores our microbes and their impacts on human health and nutrition. This is the microbial realm, and here's what it has to share.


Due to having a fascinating range of effects, microbes have become a new topic of study for many anthropologists. As technology advances, the process of studying these tiny organisms is more manageable, and driving research questions are put to the test.

One early microbial publication was authored by microbiologist Peter J. Turnbaugh who suggested a connection between obesity and human gut microbes. An experiment was done that provided substantial evidence to such a claim.

Intestinal microbes from both obese and lean humans were inserted into mice who lacked their own.

The results were shocking.

Those who received the microbes of the obese individuals also became obese themselves. The same phenomenon happened with the mice who gained the lean microbes and corresponded to them by remaining slim.

Yet, another stark discovery intrigued Turnbaugh and his colleagues. Contrary to ordinary thought, the microbes of the obese subjects appeared to be more efficient than those of the lean ones. Specifically, these microbes were generating more short-chained fatty acids that produced more energy for the organism. As a result, the hosts often had a surplus amount of energy that was stored as fat and attributed to weight gain.

Such a relationship between the microbes and the bodily health of the mice prompted researchers to further investigate other avenues of the relatively new microbial study.

Resultantly, Professor Amato began to ponder her own research questions in the interest of the primatal side of microbiomes and their benefits in a selective environment. As she continued to research, Amato started to focus on black-howler monkeys to observe their diets and interconnect microbial influences as well.

Professor Amato observing howlers in their natural habitat above.

The reason for the particular interest in this species was due to their feeding habits during seasonal changes. Once the fruit sources are depleted, most primate species will venture farther out to seek more, yet howler monkeys don't. Instead, they switch their diets to almost entirely leaves - a transition that marveled Amato.

Due to the low nutritional value and digestibility of leaves, Amato sought to understand how these monkeys were able to survive off of such a different energy source.

"It's like if you were eating apples all the time and then only ate kale," explains Amato. "That's a completely different diet."

Essentially what she found was a significant connection between the monkeys' microbes and their survivability when ingesting only vegetation. When the leaves failed to culture enough energy, the microbes produced more short-chained fatty acids to make up for the deficit.

Yet, there comes a point when a changed diet can also negatively impact one's microbiome. Amato observed howler monkeys in fragmented forests, which were void of the traditional nutrition for other primate species. Within such a lacking environment, the monkeys' microbes were no longer cushioning their survival. In fact, they were exhibiting less biodiversity and increased susceptibility to pathogens.

On the subject of primate microbiota, Amato continues to delve deeper into their influence on organismal health. For human plasticity and variation, she explains how studies have shown human microbiomes to be more diverse in function compared to those of several ape species combined. Such evidence contributes to the wide range of microbial functions in humans due to their exposure to numerous environments and pressures.

Amato's shot of Alouatta Pigra resting in trees.

Similarly, Amato explains the social influence on microbiomes. Supported by data, she reveals how studies on primates grooming one another have found similar microbiomes within those individuals. Likewise, humans living in the same residence possess microbiomes that also appear alike.

While exploring the realm of microbiota through an evolutionary and health perspective, Amato continues to embark on awe-inspiring journeys to seek the truth. Astounding questions and postulations are brought to light as she follows the road through this microscopic universe with no end.

The trip to a new world can be tough, but just as Amato shows us, sometimes all you need to bring with you is a little taste for discovery and a dash of boundless passion for that which you seek.

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