RESEARCH | IN OTHER JOURNALS
sciencemag.org SCIENCE 1548 23 DECEMBER 2016 • VOL 354 ISSUE 6319
tissue. The extracellular space
turned out to be a maze of inter-connected compartments
of multiple shapes that are
structured in a wide range of
different dimensions. This novel
technique thus allows neuroscientists to observe fine structures
of the extracellular space and
provides insights into the flow of
cerebrospinal fluid in the brain.
—PRS
Nat. Nanotech. 10.1038/
NNANO.2016.248 (2016).
MATERIALS CHEMISTRY
Reacting into new
frameworks
Covalent organic frameworks
(COFs) are formed through
moderately strong bonds
between multidentate cen-
ters and organic linkers. One
difficulty in using very strong
linkages to create more robust
materials is that the process of
crystallization must allow for
error correction, so the linkages
must be weak enough to be
reversible. Waller et al. bypassed
this problem by converting the
imine linkages in two COFs into
stronger amide linkages, using
mild oxidizing conditions. Both
materials retained their crystal-
linity and porosity and displayed
much greater stability; they were
stable after 24 hours in 12 M
hydrochloric acid, as well as 1 M
sodium hydroxide. —PDS
J. Am. Chem. Soc. 10.1021/
jacs.6b08377 (2016).
ELECTROCHEMISTRY
Tracing the trends in
oxygen reduction
Fuel cells currently rely too
heavily on expensive platinum
catalysts to reduce oxygen.
Cheaper metals still have not
matched the efficiency of platinum. Pegis et al. studied a series
of well-defined iron porphyrin
complexes in solution, in the
interest of discerning which factors would be most productive
to optimize. They found that the
turnover frequencies correlated
with overpotential, despite
rate-limiting oxygen binding.
Further grounds for optimization emerged from distinctions
between the iron redox properties and the proton transfer
characteristics of substituent
interactions in the second coordination sphere. —JSY
ACS Cent. Sci. 2, 850 (2016).
ANIMAL BEHAVIOR
Love the one you’re with
For species living near the poles,
the breeding season is short and
accelerated, leaving little time to
be choosy about finding a mate.
Such challenges are increased
in species with relatively small
numbers or that have broadly dis-
tributed mating colonies. Maftei
et al. observed mating behavior in
the rare and poorly known Ross’s
gull (Rhodostethia rosea) at a
remote Arctic breeding ground
for 3 years. They found that both
males and females regularly
courted and displayed to individ-
uals from other species. Though
this strategy did not result in
hybrid pairings, it did seem to
help the Ross’s gulls develop
their mating displays, which may
improve their performance when
it really counts and members of
their own species are available.
—SNV
Arctic 69, 341 (2016).
IMMUNOLOGY
A view to a kill, preventing
collateral damage
Natural killer (NK) cells are
immune cells that kill virally
infected target cells. To do this,
NK cells dock with their sickened
targets and unleash on them
the destructive contents of their
cytotoxic lytic granules. Hsu et
al. looked at the detailed cellular
rearrangements involved in
killing. They regulated signaling
pathways and used acoustic
trap microscopy to arrange NK
and target cells in such a way
that the lytic granules would be
released in a directed fashion
toward the targets or in a
nondirected fashion. Perhaps
unsurprisingly, when the NK
cells had the chance to line up
and release their lytic granules
directly toward their targets,
fewer bystander cells were damaged. Furthermore, killing of the
target cells was more efficient.
Inhibiting the
microtubule motor
dynein or blocking
cell adhesion molecules interfered
with targeted killing
and increased
nondirected granule
release, thereby
damaging more
bystander cells.
—SMH
J. Cell Biol. 10.1083/
jcb.201604136 (2016).
NEURODEVELOPMEN T
Blood and brain intertwined during development
During brain development, blood vasculature grows rapidly to keep up with growing brain tissue. Studying the mouse hindbrain, Tata et al. show how these events are coordinated. Peak angiogenesis during embryonic development correlates with a surge in mitotic activity of neural progenitor cells. Processes from these cells wrap around developing vessels or tag the perineural vascular plexus. The interaction depends on neuropilin-1 (NRP1), a cell surface receptor that is expressed in endothelial cells of the developing vasculature. Without NRP1,
neural progenitor cells fail to proliferate normally, resulting in fewer than normal progenitors and
compromising hindbrain growth. —PJH
Proc. Natl. Acad. Sci. U.S. A. 113, 13414 (2016).
Ross’s gulls court other species when their own
species is hard to fnd.
Vascularization
helps brain
progenitors grow.
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