Small, small world

Scientists in Europe are looking for 5,000 volunteers who'd like to have the microbes in their gut identified. If you join the project (my.microbes.eu), you'll have to pay a hefty $2,100 to have your bacterial DNA analyzed. The benefits include exchanging diet advice and stories of indigestion with others from around the world who have the same intestinal flora as you (priceless, of course).

The effort is actually quite serious and represents the frontier of the science of microbiomics, the study of how microbes interact with our bodies. The scientists behind my.microbes are building on a surprise discovery they announced in Nature earlier this year: The trillions of bacteria that help humans digest food and synthesize vitamins are organized into at least three types of microbial ecosystems, called "enterotypes." Each enterotype is characterized by a particular genus of bacteria living in domination of certain other species around it.

In the human body, microbes found in one person may not appear in the next, and particular species specialize in different digestive functions. The researchers suspect the three enterotypes may each have a subtle, unique effect on personal health-perhaps influencing weight or affecting how the body reacts to drugs. A study published by University of Pennsylvania researchers in Science last month found evidence that the enterotypes are influenced by long-term diet.

The my.microbes scientists, who work for the European Molecular Biology Laboratory, said individuals had contacted them asking whether enterotypes might explain their intestinal troubles. The scientists' effort to identify the enterotypes of people from around the globe could help answer the mystery of whether gut flora is determined by region, food choice, genes, or something else, and whether certain diseases are linked with certain enterotypes.

Motor trend

The electric motor just got smaller than ever. A team at Tufts University in Massachusetts has made a motor out of a single molecule of butyl methyl sulfide, only a nanometer wide. With the molecule's lone sulfur atom stuck to a copper base, its string of carbon and hydrogen atoms revolve 120 times per second when an electric current is applied. Other molecular motors of the same scale have run on light or chemical reactions, but the Tufts researchers, reporting in Nature Nanotechnology, say this is the first to be powered by electrons. The challenge is to get a miniscule motor to do something useful-such as deliver medicine inside the body.

Rising suns

In its persistent search for planets beyond our solar system, NASA's Kepler space telescope has for the first time confirmed the existence of a planet orbiting not one but two stars. The stars, both smaller than our sun and about 200 light-years away, also revolve around one another, and the planet they harbor is cold (negative 125° F) and about the size of Saturn. From its surface, though, you'd see an awe-inspiring double sunrise. The Kepler spacecraft finds extrasolar planets as they orbit stars by measuring regular, subtle dips in starlight. It has discovered at least 21 planets and found evidence for hundreds more.