New Scientist 14Mar2020

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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