New Scientist - AU (2022-05-14)

(Maropa) #1
14 May 2022 | New Scientist | 35

The cycle of life


A fundamental process in our cells may explain the origin
of life and the cause of cancer, finds Michael Marshall

Book
Transformer: The deep
chemistry of life and death
Nick Lane
Profile Books


IF WE want to understand the
nature of life, we have to think
about the flow of energy and
matter. So argues biochemist and
writer Nick Lane in his new book
Transformer. Quoting the poem
Like Most Revelations by Richard
Howard, he writes that “it is the
movement that creates the form”.
Lane’s focus on energy and the
essential dynamism of life has
been an important thread running
through his research. One of the
most creative of today’s biologists,
his work ranges from the evolution
of sex and the rise of planetary
oxygen to the origin of complex
cells and the first life on Earth.
In his last book, The Vital
Question, he argued that many
of these seemingly disparate
mysteries could be explained
by life’s reliance on electrically
charged particles to power itself.


Transformer is no less ambitious.
Its focus is a biochemical process
called the Krebs cycle: a whirlwind
of chemistry that spins around in
all our cells many times a second.
It is named for biochemist Hans
Krebs, who described many details
of how it works.
Lane’s thesis is that biochemists
have misunderstood the cycle
and therefore underestimated it.
Textbooks, he says, essentially treat
it as a mechanism for obtaining
energy from food. But Krebs is also
a chemical factory, manufacturing
key components of cells. And cells
can run it in various ways, so there is
no one Krebs cycle. Lane compares
it to a furiously busy roundabout,
with different vehicles constantly
whizzing in from different junctions
and hurtling out on others.
The many functions of the Krebs
cycle mean it can explain much
about life, Lane argues. For one
thing, the cycle can run backwards,
and this reverse Krebs seems to
be much older than the “forwards”
one. Lane makes the case that
it dates back to the very earliest
life, which he believes arose in
hydrothermal vents on the seabed.
He draws on recent experiments
suggesting that parts of the reverse
Krebs (and at least some of the

forwards Krebs) can happen
without complex biochemicals
to shepherd them along, and
may therefore be primordial.
Moving through the history of
life, Lane illustrates the deep links
between the reverse Krebs and
photosynthesis, which, in turn,
led to Earth’s air becoming rich in
oxygen for the first time – paving
the way for the modern Krebs,
which requires oxygen. He also
argues that alterations in the
cycle may have been key to the
blossoming of animal diversity
during the Cambrian explosion
some 540 million years ago.
Lane brings the story up to date
by delving into the role of Krebs in
cancer. Our understanding of the
disease, like our understanding of
life, has been skewed by an undue
emphasis on genes, says Lane.
For him, the key to cancer (as to
so much else) is metabolism: it is
shifts in cellular metabolism, not
genetic mutations, that explain
why our risk of cancer increases
so drastically as we age.
If that weren’t enough, Lane even
suggests that the electromagnetic
fields generated by metabolic
processes like Krebs may be the
underpinning of consciousness.
Clearly, this is a book filled with
big ideas, many of which are bold
instances of lateral thinking. Lane
says he doesn’t expect to be right
about all of it, but that is fine – even
the bits that are wrong will advance
our knowledge in the disproving.
It is a shame, then, that his book
can be dry at times. There is a lot
of nitty-gritty biochemistry – some
of it essential, but described in
exhausting detail. Get ready to
hear an awful lot about succinate,
pyruvate and alpha-ketoglutarate.
Lane tries hard to imbue these
chemicals with personality, but
his efforts only go so far. Those
who persevere will get a lot out of
Transformer, but it is hard work. ❚

The Krebs cycle may be like a busy
roundabout, as vehicles whizz in
and out from different junctions


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