2020-03-14_New_Scientist

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14 March 2020 | New Scientist | 19

Archaeology

Space Obesity

Time cells found
in human brains

A type of brain cell that
helps in the recall of the
sequence and timing of
events has been seen in
humans for the first time
(bioRxiv, doi.org/dpb4).
Time cells are in the
hippocampus (depicted
above, in red), which is
affected by early stages of
Alzheimer’s. Previously
they had been seen in rats.

Smoking bans don’t
fully protect you

You can breathe in harmful
tobacco fumes even in
non-smoking indoor
venues. Researchers at Yale
University found tobacco
chemicals in the air inside
a non-smoking cinema that
were probably released
from the bodies and clothes
of people who had smoked
or been near smokers
(Science Advances,
doi.org/ggnd43).

NASA’s next Mars
rover gets a name

The rover on the Mars
2020 mission to be
launched by NASA is now
called Perseverance. Its
name was suggested by a
secondary school student
in Virginia, and beat around
28,000 entries in a public
contest. The rover is due to
blast off in July and reach
Mars in February 2021.

Ancient humans
used out-dated tools

SKULL fragments found alongside
different types of stone tools in
Ethiopia are shedding light on the
lifestyle of the ancient hominin
Homo erectus.
Sileshi Semaw at the National
Research Centre for Human
Evolution in Spain and his team
identified two H. erectus skulls at
a site in Gona, Ethiopia.
One is 1.26 million years old and
the other at least 1.5 million years
old. They were found directly

LETTUCE is just as nutritious when
grown in space as when grown on
Earth, suggesting astronauts could
one day produce their own food.
Gioia Massa and her colleagues
at NASA’s Kennedy Space Center in
Florida analysed three batches of
lettuce grown on the International
Space Station (pictured) between
2014 and 2016. They compared
the space crop with lettuce (Lactuca
sativa) grown on Earth under
similar conditions, controlling for
relative humidity, carbon dioxide
concentration and temperature.
By culturing the bacteria found
on the lettuce and analysing DNA,
they found that there were more

microorganisms on the lettuce
from the space station than on
those grown on Earth. Massa says
this was expected. On the other
hand, the levels of nutrients in both
types of lettuce were very similar,
which was a surprise (Frontiers,
doi.org/dpbw).
The researchers decided to
use a red romaine cultivar for
the experiment because its seeds
germinate reliably and because
most people don’t actually mind
eating lettuce.
According to Massa, the
astronauts think the lettuce is
delicious and they have tried it with
tacos and cheeseburgers. JAM

alongside various stone tools.
“This is good evidence that
these hominins were the creators
of those artefacts,” says Michael
Rogers at Southern Connecticut
State University, who was part of
the team that made the find.
H. erectus evolved around
2 million years ago in Africa
and was one of the first species
we know of from our genus.
Compared with earlier
hominins, members of this
species had relatively large brains
and were adept tool-makers. They
invented the so-called Acheulean
tools, which include teardrop-

Bacteria may leak
from gut into body

BACTERIAL DNA has been found
in the blood, liver and fat of
people who are obese, showing
that either fragments of bacteria
or entire live bacteria could be
leaking from their guts.
In people who are obese the
intestinal barrier is more fragile,
says André Marette at the Québec
Heart and Lung Research Institute
in Canada. If bacteria get through
this, they could contribute to the
development of diabetes by
causing inflammation in organs.
To investigate, Marette and his
team analysed samples of blood,
liver and fat tissue from people
having surgery for weight loss.
They took many precautions to
rule out bacterial contamination.
They were surprised to find a
wide range of bacterial DNA in the
samples, including from harmful
strains (Nature Metabolism, DOI:
10.1038/s42255-020-0178-9).
They can’t say whether the DNA
came from living or dead bacteria
but think the most likely source is
gut bacteria. Living bacteria can
cause serious infections, but none
of the people showed signs of this.
If the leaking of bacteria does
play a part in the development of
diabetes, it might be possible to
develop new treatments for it,
Marette says. Michael Le Page

shaped hand axes. This
technology superseded older,
simpler Oldowan tools, which
are sharp-edged stone flakes.
Hand axes are a multipurpose
tool. It was thought that once
these had been invented,
H. erectus stopped using the
more primitive tools.
The discoveries at Gona dispel
this notion, showing that both
types of tool were used at the
same time (Science Advances,
doi.org/dpbx). This finding
suggests H. erectus was more
behaviourally flexible than we
thought. Alison George

Lettuce grown in orbit is


delicious in a cheeseburger


SCIEPRO/SCIENCE PHOTO LIBRARY


JSC/NASA

Really brief


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