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Three flavors of
intestinal bugs
By Tina Hesman Saey
There are three types of people, and by
their bacteria ye shall know them.
A consortium of researchers from
Europe and Asia examined the DNA profiles of bacteria in fecal samples taken
from 39 people belonging to six different
nationalities. Each person had a diverse
group of microbes, but closer analysis
revealed that the bacteria fall into three
major types of communities, the researchers report online April 20 in Nature.
Each of the newly identified microbial mixes — called enterotypes — is
named for the dominant type of bacteria
in the group. People with the Bacteroides
enterotype have an abundance of
Bacteroides bacteria and several associated types, while people with Prevotella
and Ruminococcus enterotypes have
more of those bacteria. Ruminococcus
was the most common of the three types.
The researchers didn’t find
any correlation between a
person’s enterotype and age,
body weight, nationality, geographic location or diet. “We
still don’t know what is driving
these three types,” says Peer
Bork, a bioinformatician at
the European Molecular Biology Laboratory in Heidelberg,
Germany. He and his colleagues speculate that the different communities may form around key bacteria
that dispose of excess hydrogen in the
form of methane or hydrogen sulfide.
Another possibility is that the first organisms to colonize a person’s intestines may
determine the community makeup. Or a
person’s immune system may determine
which microbes are allowed to settle in.
Although the species mix wasn’t linked
to any particular human trait, certain
groups of genes or biochemical functions
carried out by the bacteria did match up
with traits. “I can roughly tell you how old
you are if you give me a stool
sample,” Bork says. Body mass
index also correlated with the
presence of certain microbial
genes and biological processes.
How bacteria use their genes
is probably more important
than which species are present, says Jeremy Nicholson
of Imperial College London.
“There’s this obsession with
microbial speciation, which bugs do
what,” he says, “but what is actually
important is the capabilities of the
microbial community as a whole.”
The researchers don’t yet know if a
person’s enterotype changes over time
or stays the same throughout life, or if
certain enterotypes predispose people
to diseases.
“I can
roughly tell
you how
old you are
if you give
me a stool
sample.”
PEER BORK
Flies on meth burn through sugar
By Daniel Strain
A famous antidrug ad compares the brain
on drugs to a frying egg. Now, a study
gives a broad look at how methamphetamine might scramble the entire body.
The new research illustrates the many
genetic and cellular impacts of meth
exposure in fruit flies. In addition to
likely wreaking havoc on muscles and
sperm, the drug seems to kick a fly’s sugar
metabolism into overdrive, researchers
report online April 20 in PLoS ONE.
Though flies and people are very different beasts, meth appears to tweak some of
the same basic biochemical networks in
both, says Barry Pittendrigh, a coauthor
of the new report.
Meth batters cells throughout the fly’s
body. “It’s a really horrible compound,”
says Pittendrigh, a molecular ento-
mologist at the University of Illinois at
Urbana-Champaign. The drug seems
to kick off muscle degradation, disrupt
sperm production and even speed up the
aging process in a host of cells.
