The Human Body’s Unidentified Microbial Cities

Microbes Few of us like to dwell on the fact our human cells are vastly outnumbered (10X) by microbes in our bodies’ cellular cities. If we went by cellular per capita, rather than size of cell, we’d be more microbe than man.

In fact, various microbes have colonized nearly every conceivable part of our bodies, from the inside out. Some make us sick, but most allow us to live. In fact, without our little micro-friends, we couldn’t survive. Microbes known as “probiotics” break down indigestible food, keep us “regular”, make vitamins, and aid the immune system by keeping out harmful bacteria, among other functions.

The weird part is that most of our “bug” colonies are as of yet unidentified. (Yes, for all of our scientific advancement- we still don’t know what’s inside our insides). So far, scientists haven’t had much luck studying them, since only 1% of our body’s microbes can be grown outside of their delicately balanced “ecosystems”.  Frankly, scientists don’t know much at all about the billions of “bugs” who spend their entire life cycle within the boundaries of our bodies. But now experts say it’s time to figure out exactly what these life-forms are.

"This is completely unexplored territory that is likely to have a large impact on our understanding of human health and disease," says George Weinstock, co-director of the Human Sequencing Center at the Baylor College of Medicine, in Houston. "We hadn't been able to approach it because of the scale of the problem. But now we are finally able to open that door."

Weinstock points out that any project involving the microbes would have to be even bigger than the Human Genome project. "Even though a microbial genome is one-thousandth the size of the human genome, the total number of microbial genes in [the human] body is much greater than human genes because you have so many different species."

Since we now know the genomes that make up the human body, science would like to figure out what’s “inside” our insides. This research will likely give fruitful rewards, since various microbes are linked to all kinds of health bonuses as well as serious health risks. There are other benefits to consider as well.

"At the end of the day, we'll end up with another perspective on the evolution of our species, our human-microbial selves," says Jeffrey Gordon, a microbiologist at the Washington University School of Medicine, in St. Louis.

Gordon's research has shown just what an impact understanding our micro-tenants can make. Gordon and his colleagues discovered that obese people have a very different microbial community than lean people. Interestingly, these researchers discovered that when obese people lost weight, their micro-colonies began to morph into colonies more similar to that of a thin person.

Once we know how our microbes work, we can manipulate them to improve health and potentially prevent a host of diseases and disorders. The field of analyzing genomes of microbial communities, known as metagenomics, is relatively new. There is a lot of work to be done. Scientists are hoping to receive funding approval later this month to facilitate the research of these little critters, which could yield big results.

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