834 25 FEBRUARY 2022 • VOL 375 ISSUE 6583 science.org SCIENCE
RESEARCH | IN OTHER JOURNALS
supplementation of selenium
mimicked the effect of exercise
and reduced some of the cogni-
tive defects brought on by aging.
Understanding the mechanism
of these effects might allow
treatments that reproduce the
exercise benefit. In the meantime,
the authors note that selenium is
found in foods such as nuts, dairy
products, and grains. —LBR
Cell Metab. 10.1016/
j.cmet.2022.01.005 (2022).
BIOCHEMISTRY
Avoiding assembly
by negative design
Many diseases are caused by
mutations that affect how pro-
teins self-assemble or localize in
cells, but mapping these relation-
ships is challenging. Seisdedos
et al. randomly mutated three
residues at the surface of each of
two homo-oligomeric complexes
from Escherichia coli. In both
cases, some mutants triggered
nuclear localization and the
formation of puncta or fibers.
For one complex, this was driven
by so-called positive design,
changes that drive association by
increasing surface hydrophobicity
or stickiness. The other complex
provides an example of negative
design, in which removing nega-
tively charged residues drives
aberrant association. The effect
of alanine mutations in additional
complexes indicates that such
negative design is common.
The resulting changes in protein
assembly and localization could
be important in both normal
physiology and disease. —VV
Proc. Natl. Acad. Sci. U.S.A. 119 ,
e2101117119 (2022).HYDROGELS
Swelling polymers
with polymers
Hydrogels consist of highly cross-
linked polymers heavily swollen
with water. These soft, squishy
materials have thus found use in
biomedical applications, but they
are limited by their lack of tough-
ness and the need to keep their
water from evaporating over time.
Wang et al. developed gels based
on cross-linked poly(hydroxyethyl
methacrylate–co–acrylic acid)
polymerized in the presence of
short polyethylene glycol chains.
This combination results in gels
with high stretchability and tough-
ness and the ability for rapid
self-healing and long-term stabil-
ity under ambient conditions. This
combination of properties makethese gels suitable for pneumati-
cally driven soft actuators useful
for a robotic gripper. —MSL
Adv. Mat. 10.1002/
adma.202107791 (2022).SCIENTIFIC WORKFORCE
Not all postdocs
are created equal
Using National Science
Foundation data, Denton et
al. shed light on employment
implications for physical sci-
ences and engineering (PSE)
and life sciences (LS) postdocs
in government, industry, and
academia. The authors found
that for each sector, PSE post-
docs are shorter and offer higher
salaries than LS postdocs.
Further, transitioning from a
postdoc to permanent employ-
ment occurred more frequently
within sectors than between
sectors, although a substantial
number of academic postdocs
transitioned to different sectors.
Finally, the data showed that
the least frequent reason for
engaging in a postdoc was the
lack of other options, refut-
ing a common narrative that
postdocs are a last resort for
some. Collectively, these results
provide data with which toreconsider career development
advice provided to PhD candi-
dates and postdocs. —MMc
PLOS One 10.1371/
journal.pone.0263185 (2022).POROUS FRAMEWORKS
Alkane separations
branch out
Microporous materials such
as metal-organic frameworks
(MOFs) can enable hydrocarbon
isomer separations and have
been used to separate linear from
monobranched isomers. Yu et
al. report that a ytrrium-based
MOF containing two types of
structure-building units is effec-
tive for separating three types
of hexane isomers. The use of
less-symmetrical 5,5′-azanediyl-
diisophthalic acid linkers enabled
the coexistence of hexanuclear
Y 6 (OH) 8 (COO) 8 secondary
building units and mononuclear
Y(COO) 4 primary building units
and created a MOF with a new
topology. The pores absorbed
the more branched 2,2-dimethyl
butane more readily than 3-meth-
ylpentane, which in turn was
adsorbed preferentially compared
with linear n-hexane. —PDS
J. Am. Chem. Soc. 10.1021/
jacs.1c12068 (2022). PHOTO: VIRENDER SINGH MALIK/WIKIMEDIA COMMONS/CC BY SATwins Tashi and Nungshi Malik, who have
climbed Everest, likely share a genetic
component in their love of the outdoors.BEHAVIORAL GENETICSNature-loving inheritance
W
hy some people spend more
time outdoors could be
explained by factors such as
place of residence, parental
influence, and childhood
experience. Chang et al. found that
genetics also plays a part in determin-
ing the strength of an individual’s desire
to experience nature. Of 1100 pairs of
twins in the TwinsUK panel, compar-
ing those who were raised together
with twins raised apart and nonidenti-
cal twins revealed that nature-loving
behavior has a significant inheritable
component. Like genes make like minds.
—DJ PLOS Biol. 20 , e3001500 (2022).