12 | New Scientist | 8 June 2019
A STALLED weather pattern over
the middle of the US triggered
tornadoes in several states every
day for nearly two full weeks.
Much of the damage was in a
region known as Tornado Alley,
the core of which runs from Texas
to South Dakota. Tornadoes are
particularly common here, but
the frequency of twisters between
17 and 29 May was so high even
by Tornado Alley standards that it
broke a 40-year record.
The cause was a southward dip
in the jet stream that has been in
place over the western part of the
country for months, says Jennifer
Francis at Woods Hole Research
Center in Massachusetts.
The storms causing the tornadoes
were due to disruptions to the jet
stream in the Pacific, which were
due to Arctic warming. Francis
says models suggest that the US
Midwest will dry out this week as
the jet stream finally shifts. ❚Extreme weatherTHE microbes in our guts
could explain why people react
differently to drugs, and lead
to ways of making treatments
work better.
We know that genetic
differences can influence our
response to drugs, but recent
research has suggested that the
microbial communities inside us
could also help explain why some
people experience toxic drug
side effects when others don’t.
Most drugs are taken orally
as pills. Often, these aren’t
completely absorbed by the body,
and the remains subsequently
encounter enormous numbers
of microbes in our guts.
To see what happens next,a team at Yale University and
ETH Zurich in Switzerland
mappedhow 76 strains of
human gut bacteria break
down 271 pharmaceutical
drugs (Nature, doi. org/c6rq).
They found that 176 were
metabolised by at least one of
the bacterial strains – a strikingly
high proportion, says Michael
Zimmermann at Yale University.
The study agrees with previous
epidemiological research showingthat microbes are key to how
we metabolise drugs, says Tim
Spector of King’s College London.
“I think it’s a big step forward.
People can start to predict, based
on someone’s gut microbes, how
they might respond to a drug.”
When microbes break down
drugs, they may produce
substances with unwanted side
effects or that even render a drug’s
active ingredient ineffective.
The finding that our gut bacteria
may affect so many drugs hints
at the possibility of changing our
microbiomes to increase a drug’s
efficacy or reduce side effects.
We may be able to do this
through dietary changes or by
more drastic measures such asa faecal transplant. The goal
would be to change patients to
suit their drugs, rather than the
other way round.
The study mapped the
interactions between different
microbes and drugs by giving
human bacteria to mice, so it is
possible that the team’s findings
won’t translate to humans.
“In drug metabolism, so many
factors are involved,” says team
member Maria Zimmermann-
Kogadeeva, also of Yale University.
“It is very hard to disentangle the
microbe contribution from the
human contribution because all
the factors are happening at the
same time.” ❚MicrobiomeGut bacteria could explain drug side effects
Chelsea WhyteTornado spike in the US
A warming Arctic has led to severe storms across the States
GE
NEBLEV
INS/ZUMAWIRE
/EYEV
INENews
64.9%
of drugs tested were broken down
by at least one strain of bacteria Adam Vaughan