Zika gets an extreme close-up
Researchers have gotten the closest
look yet at the Zika virus and may have
discovered some chinks in its armor.
Using cryo-electron microscopy,
structural biologist Madhumati Sevvana
and colleagues mapped Zika’s structure
at a resolution of 3. 1 angstrom, which is
equivalent to the size of two atoms. That
closeup view, reported online June 26 in
Structure, is the most zoomed-in image
that scientists have gotten of any
flavivirus, the family of viruses that
includes Zika, dengue, yellow fever, West
Nile and Japanese encephalitis.
Comparing Zika’s structure with that
of some other flaviviruses revealed a few
differences that might account for different symptoms produced by the various
viruses, says Sevvana, of Purdue University in West Lafayette, Ind. The researchers
identified some pockets where drugs may
be able to dock and disrupt Zika, Sevvana
says. — Tina Hesman Saey
GENES & CELLS
Coffee may help protect the heart
by fueling cells’ power plants
Coffee revs up cells’ energy factories and
helps hearts recover from heart attacks,
a study of mice suggests.
Researchers gave mice the equivalent
of four cups of coffee a day for 10 days
and then induced heart attacks. Heart
cells in mice that got caffeine repaired
damage better than cells in mice that
didn’t get coffee, researchers report
June 21 in PLOS Biology. Caffeine in the
coffee helps move a protein called p27
into mitochondria, the organelles that
produce energy for cells. Increasing p27
in mitochondria upped the organelle’s
energy production, which helped heart
cells recover from damage.
Humans and other animals also have
p27, raising the possibility that caffeine
could help heal people’s hearts, too.
Normally, p27 is found in the cell nucleus,
where it helps control when cells divide.
Its energy-boosting role in mitochondria,
outside the nucleus, wasn’t known before.
Coffee seems to protect against
heart disease, diabetes and some other
ailments (SN: 10/3/15, p. 16). The new
discovery in mice may help explain why,
says study coauthor Judith Haendeler, a
biochemist at Heinrich Heine University
Düsseldorf in Germany.
Haendeler cautions that just upping
coffee consumption without doing other
heart-friendly activities, such as exercising and eating right, probably won’t do
people much good. She also warns that
drinking too much coffee or green tea
may drive too much p27 into mitochondria and destroy them, causing health
problems. — Tina Hesman Saey
ATOM & COSMOS
Solar system intruder may not
be an asteroid after all
The solar system’s first known interstellar
visitor may not be what we thought.
Evidence is growing that ‘Oumuamua,
which careened into the solar system
from parts unknown before veering off, is
a comet, not an asteroid.
Unlike asteroids, comets are icy and
tend to be surrounded by a halo of gas
and dust. Astronomers saw no signs of a
halo around the roughly 400-meter-long
‘Oumuamua. So the interloper, discovered
in October 2017, was dubbed an asteroid
(SN: 11/25/17, p. 14). But some scientists
questioned that conclusion: The object
has a reddish surface, suggestive of a
comet with an outer crust shielding an icy
heart (SN Online: 12/18/17).
Now, a team of researchers reports
online June 27 in Nature that the path
‘Oumuamua took on its whirlwind tour of
the solar system can’t be explained just
by the gravitational tugs from the sun
and other celestial bodies. Some other
force must also have been acting on the
object. That force could be a result of
spewing gas propelling ‘Oumuamua, the
scientists say, strengthening the case for
a comet. — Emily Conover
ATOM & COSMOS
Einstein’s general relativity reigns
supreme, even on a galactic scale
Chalk up another win for Einstein’s
seemingly invincible theory of gravity.
A new study shows that the theory of
general relativity holds true even over
General relativity prevailed within a
region spanning a galactic distance of
about 6,500 light-years, scientists report
in the June 22 Science. The new test is
the most precise one yet across such
great distances. Previously, researchers
had precisely tested the theory by
studying its effects on the solar system
(SN Online: 8/15/17).
According to general relativity, the
force of gravity is the result of matter
warping spacetime (SN: 10/17/15, p. 16).
The team looked at how light from a faraway galaxy was bent by that warping as
the light passed by an intervening galaxy
while traveling toward Earth. The closer
galaxy, known as ESO 325-G004 and located about 450 million light-years from
Earth, distorted the image of the distant
galaxy into a ring, like a cosmic version of
a fun house mirror (SN: 10/17/15, p. 24).
Using the observations of distorted
light, a team of international researchers
estimated ESO 325-G004’s mass. Then
they compared that measurement with
a second mass estimate based on how
stars in the galaxy zipped around and
hence how much mass was tugging on
them. The two measurements agreed,
validating Einstein’s theory.
The result challenges certain pro-
posed tweaks to general relativity, which
predict that the masses won’t match up.
For physicists, such tweaks are appealing
because they might eliminate the need
for dark energy, a mysterious pressure
thought to be behind the universe’s ac-
celerating expansion. But so far, Einstein
still reigns supreme. — Emily Conover M .
A high-resolution model of the Zika virus
shows that its envelope protein, which helps
the virus get into cells, makes three distinct
shapes (yellow, red and blue) that fit together.