Page 86 - BBC Focus - August 2017

WHO REALLY DISCOVERED?
How does physical exercise
help reduce stress?
CRISPR
LUCIE COLTMAN, VIA TWITTER

Research clearly shows that physical
exercise can reduce stress and anxiety, but
it’s less clear how this occurs. Multiple
mechanisms are likely to be important.
Exercise can help to reduce the body’s
response to stress by boosting serotonin
levels in the brain.
It can also give us a sense of achievement
and increase our self-esteem, which can
provide psychological routes by which to
EMMANUELLE CHARPENTIER reduce stress. Finally, research shows
AND JENNIFER DOUDNA that exercise taken in moderate
amounts and at appropriate times of
the day can improve our sleep. Good
sleep quality can help us to regulate
our emotions and therefore
provides another way in which
physical exercise helps to reduce
stress. AGr

BROAD INSTITUTE

Hailed as the biggest breakthrough in
genetic science this century, CRISPR is
shorthand for a molecular toolkit that
allows scientists to make precise changes
to the genetic code of living organisms.
Strictly speaking, the acronym stands for
‘clustered regularly interspaced short
palindromic repeats’, a pattern in the DNA
of bacteria first noticed by 1987. For years
the role of this pattern was mysterious,
but in the mid-2000s clues emerged that
suggested it was part of the antivirus
defence system of bacteria. Studies
showed bacteria took sections of a virus’s
DNA and built it into their own genome
using an enzyme codenamed Cas. The
resulting CRISPR sequences then allowed
the bacteria to detect an attack and fight
back. But the key breakthrough came in
2012, when teams in the US and Europe Do trees reduce air pollution levels?
led by Jennifer Doudna and Emmanuelle
ROGER LENTON, SALISBURY
Charpentier showed how the defence
system could be turned into a ‘cut and
paste’ tool for editing gene sequences. The relationship between trees and air vicinity, preventing pollution from being
However, another US team beat them pollution is a complicated one. diluted by currents of cleaner air. In
to a patent for using the method on Particulate matter suspended in polluted particular, tall trees with thick canopies PHOTOS: WIKIPEDIA, GETTY X3, ZUMA PRESS/EYEVINE
human cells, sparking a legal row over air tends to settle onto leaves, and certain planted alongside busy roads can act like
priority – and last February, the US gases including nitrous dioxide (NO 2 ) are a roof, trapping pockets of polluted air at
patent office ruled against Doudna and absorbed by leaves’ stomata, filtering the ground level. To reliably improve air
Charpentier. Despite this, they remain air and reducing pollution levels slightly. quality, city planners need to give
widely credited as the real pioneers of But trees and other vegetation also careful consideration to how trees
CRISPR by fellow scientists. RM restrict airflow in their immediate are placed. AFC

86
86