996 28 FEBRUARY 2020 • VOL 367 ISSUE 6481 sciencemag.org SCIENCE
RESEARCH | IN SCIENCE JOURNALS
isolation and characteriza-
tion. Using single-cell RNA
sequencing in a mouse model
of breast cancer, Alshetaiwi et
al. defined gene signatures that
distinguish MDSCs from other
myeloid and granulocytic cells.
They identified the protein
CD84 to be a robust cell-sur-
face marker for identification
of MDSCs in both human and
murine breast cancer. Whether
their findings can be extended
to MDSCs in other cancer set-
tings remains to be seen. —AB
Sci. Immunol. 5, eaay6017 (2020).
OPTICS
Ultrafast vortex
microlasers
For applications in ultrafast
communication, all-optical
switches will require low
energy consumption, high
speed, a strong modulation
ratio, a small footprint, and
on-chip integration. Although
the small footprint and on-chip
integration are accessible, the
trade-off between low energy
consumption and high speed
has been challenging. Huang
et al. exploited the idea of
bound states in the continuum,
effectively a high–quality (Q)
cavity without the physical
cavity, to design vortex lasers
with highly directional output
and single-mode operation.
With the trade-off between low
energy consumption and high
speed now broken, it should
be possible to realize ultrafast
optical switching that meets
all the requirements of modern
classic and quantum informa-
tion. —ISO
Science, this issue p. 1018SOCIAL SCIENCE
Economic losses from
illicit fish trade
Illegal, unreported, and
unregulated fishing—and the
subsequent illicit fish trade
market that follows—have a
substantial impact on local and
national economies. Sumaila
et al. estimate that the illicit
trade in marine fish catch adds
up to between 8 million and 14
million metric tons per year.
With suggested gross revenues
totaling $9 billion to $17 bil-
lion, the researchers estimate
potential losses of $26 billion
to $50 billion to world econo-
mies owing to the diversion of
fish from the legitimate trade
system. Bold policy and action
by both the private and public
sectors are needed to mitigate
the substantial economic
effects of illicit trade in marine
fish catch. —JJ
Sci. Adv.10.1126/sciadv.aaz3801
(2020).ORGANIC CHEMISTRY
Amines as a gateway
to alkyl radicals
In recent years, photoredox
catalysis driven by blue light
has often been used to oxidize
carbon centers adjacent to
nitrogen. Constantin et al. now
show that these aminoalkyl
radicals can, in turn, conve-
niently strip iodine atoms from
a variety of alkyl carbons. The
new alkyl radicals that result
readily undergo deuteration
and couplings such as alkyla-
tion, allylation, and olefination.
The upshot is that simple
amines can replace more haz-
ardous conventional reagents
such as trialkyltin compounds
in the homolytic activation and
functionalization of halocar-
bons. —JSY
Science, this issue p. 1021CELL BIOLOGY
Exiting without
leaving a hole
The endoplasmic reticulum (ER)
is an intracellular membranous
organelle that is sometimes
used to accommodate the
assembly of viruses or other
large macromolecular particles.
How can such entities get out
of the ER and into the cyto-
sol without disrupting the ER
membranes? During infection,
polyomavirus SV40 enters the
cytosol en route to the nucleus
after trafficking through the ER.
Chen et al. studied the release
of SV40 from the ER into the
cytosol in cultured mammalian
cells. They found that reticu-
lons—ER proteins known to be
involved in the tubular morphol-
ogy of the ER—help to protect
the integrity of the ER during
viral exit. This same function
appears to be important in the
transfer of misfolded proinsulin
aggregates directly from the ER
to lysosomes. Thus, as is their
wont, viruses have hijacked
a normal cellular pathway to
ensure their successful entry,replication, assembly, and
transmission. —SMH
J. Cell Biol. 219 , e201908182 (2020).NEUROSCIENCE
Rewiring the
adolescent brain
As children go through adoles-
cence, many undergo profound
and occasionally disruptive
changes in behavior. How
does this map onto changes
in the developing brain? Using
functional magnetic resonance
imaging in healthy young people
(14 to 26 years old), Váša et al.
observed two modes in func-
tional connectivity between
brain regions. By 14 years of
age, conservative regions, often
specialized for basic sensory
and motor functions, are already
strongly connected and con-
solidate further as an adolescent
reaches adulthood. By contrast,
disruptive regions, activated by
complex tasks, show shifts in
connectivity as a person transi-
tions between the ages of 14 and- The disruptive maturation of
connectivity between cortex and CREDITS (FROM LEFT): HUANG
ET AL.;J. LUOET AL.. CELL STEM CELL26, 251 (2020)IN OTHER JOURNALS
Edited byCaroline Ash
and Jesse SmithExperimental schematic for a vortex
laser pumped with two circular beams
Published by AAAS