Your Innner Ecosystem
In your body, bacteria outnumber your own cells by 10 to 1. Who's in control?
Source: http://www.scientificamerican.com/artic ... cts-health
How Bacteria in Our Bodies Protect Our Health [Preview]
Researchers who study the friendly bacteria that live inside all of us are starting to sort out who is in charge—microbes or people?
By Jennifer Ackerman | May 15, 2012
Biologists once thought that human beings were physiological islands, entirely capable of regulating their own internal workings. Our bodies made all the enzymes needed for breaking down food and using its nutrients to power and repair our tissues and organs. Signals from our own tissues dictated body states such as hunger or satiety. The specialized cells of our immune system taught themselves how to recognize and attack dangerous microbes—pathogens—while at the same time sparing our own tissues.
Over the past 10 years or so, however, researchers have demonstrated that the human body is not such a neatly self-sufficient island after all. It is more like a complex ecosystem—a social network—containing trillions of bacteria and other microorganisms that inhabit our skin, genital areas, mouth and especially intestines. In fact, most of the cells in the human body are not human at all. Bacterial cells in the human body outnumber human cells 10 to one. Moreover, this mixed community of microbial cells and the genes they contain, collectively known as the microbiome, does not threaten us but offers vital help with basic physiological processes—from digestion to growth to self-defense.
Bacterial cells in the body outnumber human cells by a factor of 10 to 1. Yet only recently have researchers begun to elucidate the beneficial roles these microbes play in fostering health.
Some of these bacteria possess genes that encode for beneficial compounds that the body cannot make on its own. Other bacteria seem to train the body not to overreact to outside threats.
Advances in computing and gene sequencing are allowing investigators to create a detailed catalogue of all the bacterial genes that make up this so-called microbiome.
Unfortunately, the inadvertent destruction of beneficial microbes by the use of antibiotics, among other things, may be leading to an increase in autoimmune disorders and obesity.
Source: http://www.scientificamerican.com/artic ... the-people
Your Microbiome Community Brings New Meaning to "We the People"
By Mariette DiChristina | May 15, 2012
“No man is an island, entire of itself,” wrote English poet John Donne. Nearly four centuries later science is gaining a fuller appreciation of just how literally true that is.
In addition to the bacteria that can make us sick, researchers have known for a few decades that we play host to friendly microbes as well. They help our body by performing important tasks such as breaking down food components to make them digestible or processing nutrients so we can make use of them. Although the womb is sterile, we start acquiring our microscopic guests the minute we are born.
The sheer number and broader influence of these bugs may surprise you. For starters, microbes outnumber your body cells by 10 to 1. (The bacteria are much smaller than human cells, so their total weight is often estimated to be around two to five pounds.) In effect, we are each a walking superorganism, hosting our own unique microcommunity. No two individuals share the same makeup of microbes and their genes, not even identical twins. Nobel Prize winner Joshua Lederberg dubbed this inner ecosystem a microbiome, acknowledging its complexity and interconnectedness.
More to the point, your health, your life span—and even some of your actions—may have more to do with the genetic variation in those microorganisms you host than they do with your own genes. Our cover story, “The Ultimate Social Network,” by Jennifer Ackerman, describes the efforts to map our human microbiome—no easy feat when certain critters, such as the gut bacteria that prosper in an oxygen-free environment, are challenging to grow in petri dishes in a laboratory. The results are illuminating. As you will learn, among other things, microorganism groups may influence not only how well we digest but also how much we eat. In addition, they have an important part in how well our immune system performs.
For a different kind of community effort—one involving teenagers and science that can benefit humankind—see the box at the left.
Look for the announcement of the winner of the Science in Action Award in June. Scientific American is sponsoring this $50,000 award, plus a year of mentoring, as part of the second annual Google Science Fair, a global online competition for students aged 13 to 18. The award will honor a project that addresses a social, environmental or health matter and could make a difference in the lives of a community or group. Find more information at http://www.google.com/sciencefair and at http://www.ScientificAmerican.com/science-in-action.
This article was published in print as "We the People."
More info: Ulcer and Appetite: Who's in charge? (Relative Risk blog)