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NARRATOR: Life depends on life. Plants, animals and microbes
provide us with food, clothes. Even the air we breathe.
Without the Earth's varied life forms—its biodiversity—life as
we know it wouldn't exist.
Biodiversity fuels life in another way too. It supplies
raw materials for development of new scientific tools that
ultimately help improve our health, our safety, our quality
of life. Example: Two single cell microbes recently helped
spawn a new field that's revolutionizing brain science,
and helping answer one of humanity's most vexing and
important questions: How do billions of brain neurons
interact to produce thoughts, memories, behaviors?
This new, revolutionary field is called optogenetics; it enables
scientists to selectively turn target neurons in animal brains
on and off, just by shining certain types of light on them.
Blue light turns on target neurons without affecting
surrounding cells. Orange light turns them off.
Think of the brain like the electrical circuits in your
home. To identify the function of each circuit, or type of
neuron, you could individually turn each circuit on and off to
see which electrical outlets, or behaviors, they each control.
Developed with funding from the National Science Foundation,
optogenetics is being used around the world to study
neurons possibly involved in epilepsy, Parkinson's,
schizophrenia, visual impairment, anxiety and many
other diseases and disorders. Hopes are high such studies will
ultimately lead to new treatments. Treatments that
probably wouldn't be found without biodiversity.
Here's why…brain neurons are not naturally light sensitive.
So to find a way to control neurons with light, scientists
had to draw on research about two light sensitive organisms:
the chlamydomonas algae—found in ponds and lakes the world
over—and Natronomonas pharaonis—an microbe found in
remote, super salty Saharan lakes.
The algae have a light-sensitive protein that, when exposed to
light, steers the algae towards the light so it can feed through
photosynthesis. Brain researchers discovered they can
use the algae's light-sensitive protein to make the brains of
various species responsive to blue light; once they insert the
algae's light-sensitive protein into target neurons, they can
selectively turn on those neurons merely by shining blue
light on them—and then observe resulting behaviors.
The Saharan microbe contributed a different type of
light-sensitive protein. One that helps the microbe use the
sun's energy to maintain the correct internal chemistry to
survive salty lakes.
Once researchers insert this microbe's light-sensitive
protein into target neurons, they can turn those neurons off
by shining orange light on them—and thereby stop activated
behaviors. The foundation for optogenetics was largely laid by
many studies funded by the National Science Foundation on
how the light-sensitive proteins of microbes function - studies
not led by brain scientists but by scientists who were driven by
sheer curiosity about how simple organisms survive. Scientists
who had no idea their work would ever help revolutionize the
study of the brain. Considering the importance to brain science
of an algae easily confused for pond scum and a microbe from
desiccated, abandoned ecosystems, both creatures could
serve as poster children for the conservation and study of even
seemingly useless organisms. After all, who knows what
pivotal technology might have been derived from any of the
dozens of species—some perhaps still undiscovered—that will go
extinct by tomorrow morning.
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