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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