2 November 2019 | New Scientist | 17EngineeringMicrobiome MedicationFrom a small seed,
a mighty buildingThe discovery of long
chains of cellulose that
bundle together into
cylinders may help explain
how wood gets its strength.
Understanding how they
form could help efforts to
use wood as an alternative
to steel and concrete in tall
buildings (Frontiers in Plant
Science, doi.org/dc6k).Crabs can navigate
a complex maze
A species of crab can
learn to navigate a maze
and still remember it up
to two weeks later. The
research demonstrates that
crustaceans, which include
crabs, lobsters and shrimp,
have the cognitive capacity
for complex learning, even
though they have much
smaller brains than many
other animals (Biology
Letters, doi.org/dc6n).Genome steer for
cancer treatmentThe genomes of tumours
from more than 2000
people with various
metastatic cancers has
been sequenced by a team
of researchers. They found
genetic markers that
could be used to steer those
with late-stage, metastatic
cancer towards approved
or experimental therapies.
(Nature, doi.org/dc6p).Growing heat set to
overload US bridgesHOTTER weather due to climate
change could contribute to the
failure of one in four steel bridges
in the US in the next two decades.
Bridges there and in other
high-income countries are
ageing and deteriorating. One
of the most common problems
involves expansion joints. These
allow sections of a bridge to swell
in warmer weather without
damaging the structure. But major
problems occur if they don’t work.MICE with disrupted gut microbiota
may be unable to shake off fearful
memories – suggesting our gut
bacteria may affect how we learn.
There has been growing interest
in the role gut bacteria play in our
health. Recent research has linked
disruption of these microbes to
immune system problems and
even changes in behaviour.
However, it has been unclear
how gut bacteria may cause
behavioural changes. To investigate,
David Artis at Cornell University in
New York and his team looked at
how mice learn and respond to
fearful situations.
They trained mice to fear a soundby delivering a small shock to their
paws when they heard it. Normally,
mice can gradually lose their fear
of the sound if they hear it several
times without receiving a shock.
This is known as extinction learning.
But the team found that if mice
were given antibiotics to wipe out
most gut bacteria before learning to
fear the tone, they were incapable
of extinction learning. When the
team looked at the rodents’ brains,
they found those with the disrupted
gut bacteria had different genes
switched on and there were altered
patterns of activity in brain regions
associated with fear and learning
(Nature, doi.org/dc7c). RPSHussam Mahmoud at Colorado
State University and his team
decided to model the effects of
increasing temperatures on steel
bridges in the US. They focused on
what would happen when joints
that are clogged with dirt and
debris are exposed to the higher
temperatures expected in the
years ahead as the world warms.
Clogging is a common problem,
but is costly to address. It prevents
sections from being able to safely
expand and strains parts of the
bridge that weren’t designed to
withstand the resulting load.
The researchers analysed dataSedatives dispensed
more in poorer areasBENZODIAZEPINES and z-drugs
are more commonly prescribed
in deprived areas, according to a
study of GP practices in England.
There were more than 14 million
prescriptions of these drugs, often
taken for insomnia, anxiety and
alcohol withdrawal, in 2017. This
is equivalent to 2.3 tonnes of
diazepam (sometimes sold under
the trade name Valium), or about
700 doses for each person given
a prescription, based on a typical
starting dose for anxiety.
Previous research has found
that opioid drugs are more
commonly prescribed in deprived
areas. Saran Shantikumar at the
University of Warwick, UK, and his
colleagues wondered if the same
was true of benzodiazepines and
z-drugs, which some people
become dependent on and buy
illegally. When they looked at
prescription rates in publicly
available data collected by the
National Health Service they
identified a link to deprivation
(Family Practice, doi.org/dc7s).
Perhaps people in deprived
areas may be more likely to
become long-term users of the
drugs because they don’t get
the treatment needed if they
become dependent on them, says
Shantikumar. Jessica Hamzelouon the condition of some
90,000 bridges across the US and
modelled how expansion joints
would be affected by temperatures
predicted for the next 80 years.
Current temperatures aren’t
extreme enough to cause a
problem, they found, but one in
four bridges are at risk of a section
failing in the next 21 years, rising
to 28 per cent by 2060 and 49 per
cent by 2080. Almost all could fail
by 2100 (PLoS One, doi.org/dc7m).
Lihai Zhang at the University of
Melbourne in Australia says that
developed countries around the
world face similar issues. RPSAltered gut bacteria make it
harder to get over old fears
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