SCIENCE NEWS OF THE YEAR | Genes & Cells
10 to 1 | ratio of bacterial cells in your body to your own cells
Boons and busts via gut microbes
Studying the secret lives of bacteria living in human
intestines has yielded some unexpected finds. One study
suggests that most humans have one of three different
combinations of friendly microbes (SN: 5/21/11, p. 14),
and another reveals that people’s mix of microbes depends
heavily on diet. Changing the ratios of nutrients consumed
tweaks the composition of the microbial populations in the
guts of mice carrying human bacteria, scientists find
(SN Online: 5/19/11).
Knowing just how to alter the diet to achieve the right mix
of microbes may be important for good health, both physical
and mental. At least one type of friendly bacteria can send
signals from the intestines through the vagus nerve in the
neck to influence brain chemistry and change behavior in
mice, researchers report (SN: 10/8/11, p. 9). Gut microbes
have also been found to convert a type of fat found in
meat and dairy products into an artery-clogging chemical,
and intestinal microbes may trigger multiple sclerosis, an
immune system disorder in which the body attacks its own
nerve cells (SN: 12/3/11, p. 11).
But even if some bacteria break hearts or turn a body
against itself, organisms of all sorts would be in big trouble
without them. Mice given antibiotics that kill off their
microbes can’t fight the flu as well mice that don’t take
the drugs (SN: 4/9/11, p. 14). — Tina Hesman Saey
Microbes residing in the human intestine can help digest
food or prevent infection; others can be more nefarious.
Bright cats Kittens are
engineered with a gene for
an antiviral protein that scientists hope will help combat feline immunodeficiency
virus (SN: 10/22/11, p. 9).
The cats also get a gene that
makes them glow (above).
Beneficial liaisons Humans
may have acquired important immune system genes
via liaisons with extinct
hominid cousins, the Neandertals and Denisovans
(SN: 10/8/11, p. 13).
Healthy aging After mining
the DNA of a woman who
lived to age 115, researchers
conclude that she did not
lack genetic variants predisposing her to heart disease
and other aging-related
illnesses (SN: 11/5/11, p. 9).
Genetic loophole The
occasional switch of a
chemical unit in RNA to a
slightly different form can
cause a cell’s protein-build-ing machinery to roll right
through a molecular stop
sign, a find that violates the
central dogma of genetics
(SN: 7/16/11, p. 8).
More than squirm A new
system, named COLBERT
for “Controlling Locomotion
and Behavior in Real Time,”
allows researchers to commandeer tiny worms and
pick apart behavior cell by
cell (SN: 2/12/11, p. 14).
Missing DNA, bigger brains
Humans may have devel-
oped bigger brains, spineless
penises and other traits after
losing 510 chunks of DNA,
a study suggests (SN: 4/9/11,
Gene fix A new gene therapy
allows direct fixing of DNA.
With molecular editors called
zinc finger nucleases, scientists correct a mutation
in mice that leads to hemophilia (SN: 7/30/11, p. 9).
Superbug from drugs
Antibiotics and vaccines
helped shape the evolution of
a nasty strain of pneumonia-causing bacteria, scientists
find (SN: 2/26/11, p. 16).
Lager mystery Scientists
identify a missing ancestor
of yeast used in cold-brewed
beer (SN: 9/24/11, p. 16).
Stem cell steps The body’s
immune system may attack
lab-made stem cells, a study
in mice finds, a possible
hurdle to using such cells
to replace damaged tissue
(SN: 6/4/11, p. 13). Another
study uses human eggs to
reprogram adult cells to a
state, but they have extra
chromosome sets (SN:
11/5/11, p. 8).
Burn that fat Mice lacking a
protein that responds to the
ghrelin burn more energy in
their brown fat than other
mice, hinting at a way to fight
obesity (SN: 1/15/11, p. 9).
G&C, frOM tOp: niCOlle rAGer fuller; MAyO CliniC; p. riley/univ. COlleGe lOndOn
To the heart With a little
help from cellular repro-
gramming factors, skin cells
are converted into beating
heart cells (SN: 2/26/11,
p. 16). With some prodding,
stem cells lining the outside
of the heart can also form
new heart cells (red, below)
(SN: 7/16/11, p. 9).