Techno Talk
Communing
with nature
Mark Nelson
Take equal measures of natural history and naturally occurring electronics, add a smidgeon of historical
flashback, put these in the blender and what do you get? A remarkable revelation that certainly falls
into the ‘You could not make this up!’ category.
B
eginning in the late 1890s,
Tesla (the inventor, not the car)
spent more than ten years developing a means of generating and
transmitting wire-free electrical power
over long distance directly into homes
and factories. In 1900, he expanded this
notion to propose a ‘World Wireless
System’ that could broadcast not only
power but also information worldwide.
Construction began a year later in New
York state to build a large high-voltage
wireless power station. Unfortunately,
the money ran out before his ambitious
new facility could be completed, and neither his miracle machine nor his global
broadcasting system ever became reality.
Knowledgeable as Tesla was, he had no
idea that Mother Nature had already accomplished these feats biologically – in
a manner of speaking, at least.
Nature’s grid is global
‘The ground beneath our feet, the entire
globe, is electrically wired’, states Nikhil
Malvankar, assistant professor of molecular biophysics and biochemistry at the
Microbial Science Institute at Yale’s West
Campus and senior author of a recent
paper in the journal Nature. ‘Previously
hidden bacterial hairs are the molecular
switch controlling the release of nanowires that make up nature’s electrical grid.’
These nanowires exist on land and
sea, permeating all oxygen-less soil and
deep ocean beds to create a global web of
bacteria-generated nanowires, he continues. A hair-like protein hidden inside the
bacteria serves as a sort of on-off switch
for nature’s ‘electricity grid’. But whereas
the UK national grid delivers multi-purpose power, the natural nanowire grid
performs only one function: to enable
bacterial life to exist in the absence of air.
Snorkelling bugs
Almost all living things breathe oxygen
to get rid of excess electrons when they
convert nutrients into energy. Without
access to oxygen, however, soil bacteria
living deep under oceans or buried underground over billions of years have
developed a way to respire by ‘breathing
minerals’, like snorkelling, through tiny
10
protein filaments called nanowires. Just
how these soil bacteria use nanowires to
exhale electricity, however, has remained
a mystery to scientists until recently. The
general belief was that the filaments were
made up of a protein called ‘pili’ (Latin
for ‘hair’) that many bacteria show on
their surface.
However, in research published in
2019-20, a team at Yale led by Malvankar
showed that nanowires are made of entirely different proteins. ‘This was a
surprise to everyone in the field, calling
into question thousands of publications
about pili,’ he said. For the new study, two
graduate students used cryo-electron microscopy to reveal that this pili structure
is made up of two proteins, and instead
of serving as nanowires themselves, pili
remain hidden inside the bacteria and
act like pistons, thrusting the nanowires into the environment. Previously,
nobody had suspected such a structure.
The discovery is of far more than academic interest, naturally. Knowing how
bacteria create nanowires will allow scientists to tailor bacteria to perform a host
of functions – from combatting pathogenic infections or biohazard waste to
creating living electrical circuits, the
Yale team says. It will also assist scientists seeking to use bacteria to generate
electricity, create biofuels, and even develop self-repairing electronics.
The biological WWW
Mother Nature has her own WWW, which
she successfully constructed many aeons ago, without assistance from Sir Tim
Berners-Lee, who invented the World
Wide Web only in 1989. It was a British
plant scientist, Merlin Sheldrake, who
gave the biological WWW its ingenious
name, calling it the ‘wood-wide web’
and popularising understanding that
trees (and other plants) can share nutrients and they can warn each other of
threats to their wellbeing. The possible
existence of electro-biological communication between plants was first raised
in 1988 (a year before the official WWW
was invented) by another plant scientist, E.I. Newman, who argued that fungi
could probably communicate with one
another via their fungal root tissues, stating: ‘If this phenomenon is widespread,
it could have profound implications for
the functioning of ecosystems’.
Multifunctional
Since then, research carried out by
Sheldrake and others has positively
proved the existence of these versatile
networks just below the surface of the
ground. In these unseen subterranean
ecosystems, fungi act as facilitators to enable other plants to share nutrients such
as nitrogen, sugar and phosphorus. Not
only is the network an entirely mutual
affair, with widespread inter-species communication, but it is also multifunctional.
To explain this, I cannot do better than
quote the New Yorker magazine, ‘A dying tree might divest itself of its resources
to the benefit of the community, for example, or a young seedling in a heavily
shaded understorey might be supported with extra resources by its stronger
neighbours. Even more remarkably, the
network also allows plants to send one
another warnings. A plant under attack
from aphids can indicate to a nearby plant
that it should raise its defensive response
before the aphids reach it.’
Information transfer techniques
Although this ‘other’ WWW is fundamentally biological, it shares analogies
and functions with familiar electronic
principles, as two Wikipedia articles
explain. The first – see: https://bit.ly/pejan22-tt1 – states: ‘The flux of nutrients
and water through [fungal root] networks has been proposed to be driven
by a source-sink model, where plants
growing under conditions of relatively
high resource availability (eg, high-light
or high-nitrogen environments) transfer
carbon or nutrients to plants located in
less favourable conditions.’ The other –
see: https://bit.ly/pe-jan22-tt2 – provides
the electronic connection. ‘Plants connected by a [fungal root] network have
the ability to alter their behaviour based
on the signals or cues they receive from
other plants. These signals or cues can
be biochemical, electrical, or can involve
nutrient transfer.’
Practical Electronics | January | 2022
