25 years ago, Venezuelan microbiologist María Gloria Domínguez Bello, from Caracas, began doing research with indigenous communities. That experience has been very revealing, and not just in scientific terms.
When she talks about her incursions into the South American jungle, her enthusiasm and gratitude to the populations that have allowed her and her colleagues to enter to see how they live is evident. “We have a lot to learn from them”, she says admiringly.
In an article she wrote for Cell magazine, in 2016, Domínguez offered some details of a visit they made to a town several years ago. The first day they focused on the formal presentation of the team of researchers to the leaders and tnity, who had approved their arrival in advance, and communicating their objective.
“They are familiar with intestinal worms, some of which are visible. We explained to them that there is a tiny life smaller than worms: microbes in Spanish and Portuguese, in the intestine, mouth, skin, vagina, a few harmful, but mostly good and that we still don’t understand their role. We let them know that traditional peoples like them seem to have a more diverse set of microbes than ours and that we want to understand why. “
Start hunting for microbes
The dilemma between studying medicine or biology did not last long: to study the first degree at the Central University of Venezuela, you had to wait a year; while the second could be started immediately at the Simón Bolívar University.
Domínguez did not want to wait and, over time, she was captivated with the microbiome or microbiota. Essentially, they are the microorganisms that live in the human body. She did a Master’s degree in Nutrition and a PhD degree in Microbiology, both of them at the University of Aberdeen, in Scotland.
She also worked at the Venezuelan Institute for Scientific Research (IVIC) from 1990 to 2002. After that, she left Venezuela to teach her major at the University of Puerto Rico.
In 2012, she decided to go to the United States, where she resides now. Today, she is a professor of biochemistry and microbiology at Rutgers University. There, she leads the laboratory that bears her name that focuses on the co-evolution of the microbiota and the host, and the impact on these dynamics of Western lifestyle practices.
“The search for microbes has led me to travel through the intestines of rodents, ruminants, birds, and humans, through savannas and jungles in South America and, more recently, in Africa”, she said in the Cell article, which she titled: A Microbial Anthropologist in the Jungle. And, as she explains, her approach as a microbiologist of human populations has been very anthropological.
“But, beyond studying diseases, the questions I ask myself are: Why do we have this? Where did this come from? When did we acquire this symbiosis?”
One of her research projects is focused on the microbiome of isolated peoples. She studies microbiota that has not been affected by factors such as antibiotics, caesarean sections, or over-cleaning. “The idea for us has always been: what we learn from them we tell them because they have a lot to teach us”, says the expert.
In that country, she has studied different indigenous communities such as the Piaroas, the Guahibos, the Yekwanas, the Waraos, and the Yanomami. “The first studies were nutritional and we did them in collaboration with anthropologists”, she says. “We studied populations of different ethnic groups near Puerto Ayacucho, the capital of the Amazonas state, in Venezuela”.
The initial interest was to understand their diet, but another interest soon emerged: “How is it possible that these people have so many parasites and are asymptomatic?” So, she recalls, she began to wonder: “Could it be that we evolved to have parasites and when they get out of control we get sick?”
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And it is that many of the individuals that she studied in these communities, “almost all of them had different protozoa.” “We found their nutritional status, at least in traditional indigenous populations, to be excellent.” “Nature provides them with their diet in abundance; they cultivate in their gardens and often go to the river”.
The mentioned situation changes dramatically for many indigenous people who decide to move to urban centers: “As they move to cities, you can see the other side of the story: obesity and malnutrition”. She also “wanted to understand how the microbiota are associated with the loss of the traditional diet and the transition to much less healthy diets, high in fat and carbohydrates, without fiber”.
Greater diversity
Her research studies with some indigenous populations reflect a remarkable diversity of microbiota among its members. In the most remote communities, she says, they have been able to obtain, from their members, samples of different parts of the body (skin, nose, and mouth), taken with swabs. “In the faeces of the highly isolated Yanomami, there is almost twice the bacterial diversity that we have.”
In 2015, Domínguez published, along with 22 other researchers, the article “The Microbiome of Uncontacted Amerindians”, in which she presented the findings of a study with a small Venezuelan Yanomami community “without prior documented contact with Western people”. “In 2008, an uncharted village was spotted by an army helicopter and, almost a year later, a medical mission (sent by the authorities) landed there, in 2009”, that document states.
Aware of their isolation, only one of the authors, Dr. Óscar Noya, was at the scene. It is a community of hunters and gatherers, without agriculture techniques or domestication of livestock, which agreed to participate in the research. “The trade was evidenced by the presence of machetes, cans, and clothing that are usually exchanged for arrows with other Yanomami groups. The age of the 34 people (those who participated) ranged from 4 to 50, as estimated by Yanomami health workers on the medical team”.
After analyzing their “fecal, oral, and skin bacterial microbiome”, Domínguez and her team found that “they harbor a microbiome with the greatest diversity of bacteria and genetic functions ever reported in a human group”. Despite their isolation and “with no known exposure to antibiotics, they harbor bacteria that carry functional antibiotic resistance genes, including those that confer resistance to synthetic antibiotics”.
Although the authors recognized that the sample size was small, they noted that the results suggested that “Westernization significantly affects the diversity of the human microbiome”.
To be continued……
