7 December 2019 | New Scientist | 19BiotechnologyAncient humans SeismologyClimate change
food supply alertUsing state-of-the-art
climate and crop models,
researchers have calculated
that, in the worst-case
climate change scenario,
about 90 per cent of the
global population will live
in countries where both
farms and fisheries have
falling food productivity by
2100 (Science Advances,
doi.org/df8j).Air pollution linked
to hospital visitsAdmissions to hospital go
up when air pollution is
high. An analysis of more
than 95 million US records
has revealed that, for every
1 microgram per cubic
metre increase in fine
pollution particles on a
given day, admissions went
up by more than 2000
people (BMJ, doi.org/df8k).Vaccine may spell
end of bovine TBA modified version of
the BCG vaccine against
tuberculosis could allow
cattle around the world to
be vaccinated against the
bovine form of the disease.
At present, infected cattle
are killed and animals
thought to spread TB, such
as badgers, are culled,
which has been a source
of controversy (Scientific
Reports, doi.org/df8n).Modified microbes
eat greenhouse gasBACTERIA have been rewired to
live off carbon dioxide and could
be used to produce biofuels in a
more sustainable way.
We already use strains of E. coli
to make biofuels, chemicals and
medicines, such as insulin.
However, they are usually fed
sugar. Ron Milo at the Weizmann
Institute of Science in Israel and
his team have used a process
called directed evolution to make
the bacteria consume CO2 instead.NEANDERTHALS may have died out
not because of competition from
our species, but sheer bad luck.
Fossils of Neanderthals (pictured)
mean we know they lived in Europe
and Asia for hundreds of thousands
of years. However, their population
was always small, probably just a
few thousand, and they died out
about 40,000 years ago.
At this time modern humans were
entering Europe from Africa in large
numbers for the first time. As a
result, many researchers suspect
our species was somehow to blame.
But Krist Vaesen of Eindhoven
University of Technology in the
Netherlands and his team say thatmay not be the case after simulating
the Neanderthal population.
They tracked three processes that
could have made the Neanderthals
vulnerable. The first is inbreeding,
which can lead to a build-up of
harmful mutations. The second is
the Allee effect: in tiny populations
finding a suitable mate is harder.
Finally, there is random chance.
For instance, unusually high death
rates in a single year can be
catastrophic for a small population.
The team’s simulation covered
10,000 years and found these
three processes were enough to
lead to extinction (PLoS One,
doi.org/df77). Michael MarshallThey added genes to the E. coli
genome for an enzyme that
converts atmospheric CO2 to
biomass and deleted genes
needed for sugar metabolism.
The researchers then left the
bacteria for several months. After
200 days, they found that the
microbes had successfully evolved
to grow without needing sugar
for food (Cell, doi.org/ggdmhq).
Milo says he didn’t expect to
be able to make such “drastic
changes” to the microbe’s
natural mode of growth.
Currently, the bacteria still emit
more CO2 than they consume asInternet cables can
sense earthquakesFIBRE-OPTIC cables that bring us
speedy downloads can be used for
detecting tremors.
Nathaniel Lindsey at the
University of California, Berkeley,
and his colleagues temporarily
turned 20 kilometres of existing
underwater fibre-optic cables into
a row of seismic sensors under the
Pacific Ocean just off California.
They recorded a 3.5-magnitude
quake and discovered a new fault
system close to the coast.
An extensive underwater
network of these cables, which
carry light, connects all the
continents except Antarctica and
transmits telecommunications
data, including internet traffic.
The researchers used a
technique called distributed
acoustic sensing, which works by
sending pulses of light through a
cable and analysing light that
returns to detect slight movement.
During a four-day experiment,
the team measured an earthquake,
as well as the scattering of the
quake’s wavefronts by previously
unknown faults in Monterey Bay.
The method could be used to
turn other cables that aren’t in
use into offshore seismic sensors
to map underwater faults and
earthquakes more extensively
(Science, doi.org/df8m). DLpart of the growing process, but
the researchers think they may be
able to change this in the future.
Because E. coli is easily
manipulated and already widely
exploited for biotechnology,
the possibilities of using it are
“endless”, says Frank Sargent
at Newcastle University, UK.
The bacteria could use CO2
generated by the steel or concrete
industry to make insulin, for
example. “This type of directed
evolution is already a Nobel prize-
winning type of science and this
is a terrific example of why,”
says Sargent. Gege LiWe may not have killed off
the Neanderthals after all
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