I've had this article sitting on my "to blog" list for a while: Bugs Inside: What Happens When the Microbes That Keep Us Healthy Disappear? The human body has more microbial than human cells, but this rich diversity of micro-helpers that has evolved along with us is undergoing a rapid shift--one that may have very macro health consequences. At my last "real" job at The Institute for Genomic Research (Now known as J. Craig Venter Institute, because that is the boss's name, and he's not a bashful fellow) I wrote some grants to sequence microbial ecosystems. It was too early in the microbial genome sequencing game for those proposals to fly, but now several organizations are doing just that. It's been 11 years since I left, so I guess I was right not to stick around waiting for it to happen, but I'm feeling a little envious of the folks who are getting to do that work now.
Sea water microbes, oil well flora, rumin ecosystems, and human "normal flora"--it's a way to get a look at bacteria in non-homogeneous culture, and characterize "bugs" that can't be cultured individually. Of course, the normal flora of humans are of particular interest.
Having evolved along with the human species, most of the miniscule beasties that live in and on us are actually helping to keep us healthy, just as our well-being promotes theirs. In fact, some researchers think of our bodies as superorganisms, rather than one organism teeming with hordes of subordinate invertebrates....
With rapid changes in sanitation, medicine and lifestyle in the past century, some of these indigenous species are facing decline, displacement and possibly even extinction. In many of the world's larger ecosystems, scientists can predict what might happen when one of the central species is lost, but in the human microbial environment—which is still largely uncharacterized—most of these rapid changes are not yet understood. "This is the next frontier and has real significance for human health, public health and medicine," says Betsy Foxman, a professor of epidemiology at the University of Michigan (U.M.) School of Public Health in Ann Arbor.
Meanwhile, each new generation in developed countries comes into the world with fewer of these native populations. "They're actually missing some component of their microbiota that they've evolved to have," Foxman says.