[calm music] - Hi there, I'm Frank Graff.

Thomas Jefferson called the Blue Ridge Mountains, "Humble and homespun," but also one of the most culturally fascinating mountain ranges in the world.

The science of North Carolina icons like the Blue Ridge coming up on SCI NC.

[upbeat music] - [Announcer] This program was made possible by contributions to your PBS station, by viewers like you.

- [Narrator] Additional funding for the SCI NC series is provided by GSK.

[techno music] - Hi again, and welcome to SCI NC.

You know, the Blue Ridge Mountains look pretty good for their age, more than 1 billion years old, but what is the secret to their namesake color?

Our story is from Overview, a series PBS North Carolina produced for PBS Digital Studios.

[upbeat soft music] - [Narrator] Look to the horizon on a clear day in Western North Carolina.

And you'll see a soft dreamy blue haze.

These mountains are so blue, the Cherokee tribes, native to the region called these mountains, Shaconage, the place of blue smoke.

All this dense vegetation is breathing.

And while trees are inhaling pollutants like carbon dioxide, they're also exhaling compounds that could be dangerous to your health.

[woodsy guitar music] But before we start clear cutting the forest, let's back up.

The Blue Ridge Mountains are home to at least 150 native tree species.

Compare that to Great Britain which only has less than a quarter of that.

The reason this area is so diverse is because it was too far South to be covered by glaciers in the last two ice ages.

So these mountains became a refuge for plants and animals escaping the ice.

And what you can't see is that this rich assortment of trees are all emitting microscopic VOCs, or volatile organic compounds, the source of the Blue Ridge Mountains signature haze.

- [Howard] So there are many multiple layers of leaves in the forest.

They're all taking in CO2.

They're all giving off moisture and they're also producing VOCs.

- [Narrator] Dr. Howard Neufeld is the Blue Ridge Mountains tree expert.

- Want me to hug a tree?

- [Narrator] But his other love is air quality, And the role that plant VOCs play in it.

VOCs are kind of like human pheromones.

It's thought that plants emit them to communicate distress and to repel or attract insects.

- [Howard] And those may act as signals to nearby plants that, hey something is munching on me.

Maybe you'd like to be protected.

- [Narrator] The smell of freshly cut grass.

That's a VOC.

And so is that classic Christmas tree smell.

Here in the mountains, fine mists of VOC particles scattered blue and violet wavelengths more than the other colors of the light spectrum.

And since the color receptors in our eyes are more sensitive to blue than violet.

We perceive a blue haze bathing the mountains.

But VOCs do more than just scatter blue.

This is kind of an environmental paradox but as trees soak up CO2, they also emit one of the key ingredients of ground level ozone, a potentially dangerous pollutant.

Mix VOCs with the chemicals released from burning fossil fuels, zap them with sunlight, and you'll get ozone.

The world's plants emit 500 million tons of VOCs every year.

And that can make a lot of ozone.

Higher up in the atmosphere, ozone is a good thing.

Shielding the planet from ultraviolet radiation, but ground-level ozone can cause breathing problems.

The kind you most often hear about in big cities, not national forests and parks.

By the mid 90s, ozone levels in parts of the Blue Ridge Mountains, rivaled cities like New York and Atlanta.

But the trees alone weren't to blame, it was the trees plus a whole lot of imported pollution from coal country.

Starting in the 1970s, scientists noticed that the Blue Ridge Mountains started looking less blue.

- [Howard] I remember going to the Smokies in those years and I couldn't see any of the mountains at all.

It was just a white wall almost like it looked like white sheet rock.

You wouldn't even know the Smokies were there.

- [Narrator] Here's some photos from the Great Smoky National Park during the mid 90s.

Not only is there very little blue but you can barely make out a mile in the distance.

When the park first opened in the 1930s, visitors can make out landmarks 65 miles away on a clear day.

Here's the problem.

The chain of Blue Ridge Mountains is perfectly situated downwind of some of the biggest coal-producing areas in the country, like the Tennessee and Ohio River valleys.

Winds carried about a third of those emissions over the Blue Ridge Mountains.

Back in the 90s, before modern regulations, power plants could belch out as much nitrogen oxides and sulfur dioxide as they wanted.

These same pollutants are released from car tailpipes.

So the problem was compounded by the none million tourists that flood mountain roads every year, not only were the views disappearing, the air is becoming dangerous to breathe.

The combination of jam packed roads, tree packed forests and unfettered coal production made this mountain oasis, an unlikely health hazard and tourists were often disappointed by the views.

Man-made compounds create a haze too just not a pretty haze, like plant VOCs do, instead of scattering, hues of blue they scattered hues of gray and yellowish brown.

[water gushing] There are so few environmental stories with happy endings but this is one of them.

As part of the Clean Air Act, States put limits on how much sulfur dioxide and nitrogen dioxide could be released from power plants and tailpipes.

- [Howard] The clean air act is an example of how we can come together as a nation.

We recognize that air pollution knows no political boundaries.

So you have to pass laws that look at the entire airspace.

That's why the Clean Air Act is a national clean air.

- [Narrator] And as natural gas and renewables get cheaper to produce, coal-fired plants are slowly powering down across the country.

Since 2015, only one new coal plant has been built in the US.

It's a huge departure from just a decade ago when nearly half the electricity used in the US came from coal.

Today, that number is more like 20%.

That chain is made tangible by how many miles you can see in the distance on a clear day in the Blue Ridge.

And of course in the blue on the horizon.

[soft music] - If the Blue Ridge Mountains are iconic to North Carolina, so is kudzu.

It was introduced here as an ornamental plant but that plant went very wrong.

SCI NC Producer Rossie Izlar introduces us to some folks working on new uses for kudzu.

[upbeat music] - Here in the South.

We've learned to hate kudzu.

This vine covers everything in its path with a luscious green death mat.

Kudzu is the poster child for invasive species in the South.

And it's a classic tale of human hubris.

We deliberately planted it and it got out of control.

But now that it's here, should we just start using it?

[upbeat soft music] Pretty good, yeah, but kind of sweet.

That's what Justin and Lauren think we should do.

They make kudzu hot chocolate.

They weave kudzu cloth from the vines.

They process starch from the roots.

They're huge kudzu fans and they want us to love it too.

- [Justin] I look at this Kudzu patch.

That to me is a bank of resources going into the future.

- Kudzu's story in the United States began in 1876, at the first American hosted World Fair in Philadelphia.

The same World Fair that introduced Americans to ketchup, and the telephone.

Plant catalogs started selling kudzu calling it the most remarkable hardy climbing vine that should be planted by everyone desiring dense shade, but it might not have become such a monster if it wasn't for the federal government.

In the 1930s, agriculture in the South was in trouble, intensive tobacco and cotton farming had depleted nutrients in the topsoil and farmers started harvesting timber for extra cash which further depleted the soil by causing erosion.

Farmers needed something to anchor the soil and to the federal government, Kudzu seemed like a good solution.

It's extensive root system and nitrogen fixing properties would heal the soil and also feed cattle with its nutritious leaves.

So the Soil Conservation Service paid farmers to plant their land with Kudzu, eventually handing out 84 million seedlings.

But by the 1950s, farmers realized they couldn't easily make money on kudzu and most of it was plowed under or eaten by livestock.

The only place where kudzu really thrived was along highways where it had easy access to sunlight and it quickly dominated.

So instead of being the solution to our erosion problems, kudzu became an uncontrollable weed.

Putting pressure on a number of rare species found only in the South.

[cool music] But Lauren and Justin want us to change your minds about Kudzu.

So we're visiting them in Sylva, North Carolina to harvest some.

So Justin here we are in this beautiful Kudzu patch, as far as the eye can see.

What's the plan?

- So we're gonna see if we can find some kudzu roots.

I suspect we will.

In this area, there are probably maybe 100 kudzu roots.

- Some cutting.

- Can yor reach that one there?

- Yeah!

- So satisfying.

Digging.

We pulled out a kudzu root.

Ooh, what have we got?

It's huge.

- Wow.

- Ta da!

- One of the really amazing things that I like to share with people that really made me start to rethink kudzu is that in the places where it comes from just about every single part of the plant is used in a really big way.

Not just like little craft items, but like as a staple food and like a big part of traditional Chinese medicine, they use hundreds and hundreds of herbs, and kudzu is one of the top 20.

- So it's an untapped resource that we just need to change our mindsets.

- I think so change our mindsets is one and then learn kudzu culture, which is like, you know, how to work with the plant, how to harvest it, when to harvest it, what to harvest, how to use it, how to appreciate it, how to make art and beauty with it.

[upbeat soft music] - So we've got our Kudzu root from the field and we've cleaned it.

And then what happens?

- Then we chop it, we'll shred it, [machine whirring] and then we'll pulverize it so that the starch and juice starts to separate.

And then we'll go through a rinsing and settling process to then get the final starch.

- [Justin] The starch is really quite magical stuff.

- It's used as a thickening agent for sauces.

And you can make this really jelly kind of noodle with it, jams or jellies, and desserts, pastries and breads.

It's an existing abundant crop.

And we have this bias associated with it that to see the value in it, you have to overcome that bias and to do that, you have to learn what other people have done and what people are still doing today in areas of the world where the plant is native.

- You know where this is going, right.

If we all start eating kudzu, then maybe we could keep it in check.

Well, we talked to Owen Carson, the president of the Invasive Plant Council and he sort of threw cold water in our faces.

Not really, but kinda.

- It's ultimately not a problem that we can eat our way out of.

It's a really deep rooted issue, pun definitely intended, in Asia where it originates.

There are natural controls there that work against kudzu.

So there are other plants that suppress its growth.

There are a fungi and pests and pathogens.

They're all native to that part of the world.

And so, one of the biggest issues is when you remove a plant from its native ecosystem and put it in a place that has very similar climate, similar resources but none of those bio controls, it's gonna go crazy.

- A 2005 study found that invasive plants and animals cost the US $120 billion in damages every year.

They out-compete native plants for resources, spread diseases and are the leading cause of animal extinction and population decline.

Kudzu itself isn't even the worst of our invasive species.

We think of kudzu first because it's what we see along the highway.

But if you look deeper into forested lands in the South, you'll find things like Asian privet, which covers 3.2 million acres, an area roughly the size of Connecticut or take Oriental bittersweet in the Appalachian mountains.

- It pulls down mature forest.

It creates these vine environments called lianas that are suppressive to biodiversity.

The food that bittersweet offers to native birds is a poor quality than those of native fruits.

You have all sorts of disrupters extending out into the ecosystem from a plant like that.

- So if we can't eat our way out of this problem, what should we do about it?

Well, hey, here's an idea.

Don't plant these plants.

Thankfully, you can't buy kudzu at a greenhouse anymore but people still ask the folks at Kudzu Culture if they have any seedlings?

- We think, kudzu's a great plant.

We love everything about it, but there's already plenty of kudzu.

- But there are hundreds of invasive plants that you can still buy from a greenhouse, like privet.

In the meantime, yes, let's drink the Kudzu Kool-Aid or in this case, kudzu hot chocolate.

Seems like eating the plant that sort of ate the South is good karmic justice.

[upbeat music] - World-class universities are also iconic to North Carolina.

Duke University Medical Center is part of a network of medical centers around the country that are using cutting edge science to identify and possibly cure mysterious illnesses.

- Just hanging out with a bunch of friends, shooting some basketball.

I went to go shoot.

And all of a sudden everything turned white.

Chest was pounding really hard.

I had jaw pain.

I had pain up and down my left arm.

Oh God!

I was like, am I having a heart attack?

And I was like, no kid my age has a heart attack.

[sad music] - [Narrator] Doctors diagnosed an acute cardiac event, cause, unknown.

Ethan was fitted with an implanted defibrillator, prescribed heart medicines, told to stay away from intense contact sports.

Warned another attack could happen anytime.

- It's like a bug, a gnat, just flying around your ear in the hot summer.

It just stays in the back of my mind constantly.

Always think about it.

There's probably not a day I go by without thinking about the situation.

- [Narrator] It marked the first chapter of a medical mystery for the family.

The couples son, Hogan, who had been adopted by another family, died at age 17, also of an acute cardiac event.

The cause was unknown.

The mystery deepened when tests showed other siblings also shared the same heart defect.

- He had the same thing as Ethan.

And then they were concerned that you have two children with it.

This is genetic.

There's someone else still that has this as well.

Don't do anything 'cause we need to test everybody.

And unfortunately we found out our oldest Austin also has it.

Thankfully not as severe.

- It's kind of rough, you know dealing with it, as you know because you don't know exactly what your limits are, cause I've always been the type of person that pushed my limits.

I pushed my limits.

I was in ROTC.

I wanted to join the military, all this stuff, and I found out about this and it just sent me through a loop.

I've gotta settle my limits down a little bit.

- I was just blown away by it.

Like, okay, what's going on?

You know, I was just flabbergasted pretty much.

- [Narrator] How could three brothers raised in different families in different parts of North Carolina develop the same condition?

The family turned to the Undiagnosed Diseases Network for answers.

It's a group of 12 clinical research hubs that gather experts in multiple fields to study mysterious chronic diseases.

Duke University Medical Center is a member.

- When they come to us with these concerns and with these diseases, our job is then to try to find where in the genome, where in the book, these spelling errors can be that can cause their disease.

And that's the key to figuring out whether we can find family members who might be at risk of dying.

Even if all the clinical testing is negative.

- A lot of families come into this study not necessarily thinking that anything is going to benefit them personally but they really do want to contribute to what is known about this condition so that maybe someone else will benefit from this knowledge.

Maybe someone else won't lose a child to this condition.

- [Narrator] Since 2015, the Duke team has accepted 199 applications and made 79 diagnoses.

That's a diagnosis rate of about 40%.

- I think I've been a medical geneticist for 25 years now.

This is the first time I've ever felt that I can go beyond whatever I was doing before.

And there are new frontiers here for diagnosis, for new disease, gene discovery, and even treatments and finding out what causes a particular disease?

- [Narrator] The investigation begins with a blood sample that allows researchers to study the patient's DNA but they can also use molecular genetics and trick the blood into reverting back into stem cells.

- It's got kind of a long name but it's induced pluripotent stem cells.

These are stem cells that are made specifically from the blood.

And that gives us a very powerful tool so that we can create from those stem cells any tissue we want from those patients.

And it's like having their tissue here in the lab.

- So you have a blood cell, which is a differentiated cell and then you bring it back to its original form where it doesn't know what it is yet.

And then you retell it to become another cell.

So there are particular growth factors, instructions for each cell that need to be provided from the stem cells to become that type of cell.

- [Narrator] The entire process takes four to six months.

And now there is a tray with the family's heart cells ready for study - These are your cells.

You are a human you've just put them on a plate.

You have to feed them.

You have to take care of them.

They have certain gas requirements, certain heat requirements.

It's like caring for a plant, but a lot harder.

- [Narrator] Researchers can compare the differences between the patient's cells and normal heart cells.

- And what we found was a spelling error in a gene that no one would ever have thought could be associated with this disease.

The silver lining to this family's tragedy is that by figuring out this spelling error elsewhere in the genome, we can learn a lot more about the heart, because we had no idea that this particular chapter, this particular gene is associated with disease.

By studying this family or partnering with them we might be able to learn a lot more about hearts of children and young adults in general.

You've given us an incredible gift that we couldn't do any of us without you.

- I think what I'm really excited about is to hear how just us little people, how that will make a difference in other people's lives, like how that can change.

I know it's minor but it's like getting that, this is the gene that cause that.

- [Narrator] Hey parents, teachers, and homeschoolers, looking for lesson plans?

You'll find free interactive ones about all types of science covered by SCI NC online.

- Fire ants.

Unfortunately could also be called iconic to North Carolina.

Researcher Adrian Smith with the North Carolina Museum of Natural Sciences gets us up close and personal with fire ants, but without the bites.

- In the 1950's, North Carolina gained a new permanent resident.

An invasive insect species that entered the US in the 1930's in Mobile Bay, Alabama, and spread throughout the Southeast.

It's the red imported fire ant, solenopsis invicta.

This is the mound of a fire ant colony, and if you've ever stumbled into one of these, you know why they are called fire ants.

They have a very painful sting, and they are quick to deploy it in defense of their colony.

[upbeat music] Given how many people encounter and are stung by fire ants, I was surprised that there was no detailed video showing what stinging behavior actually looks like.

So my expertise are in filming insects and studying insect behavior.

So I've been filming a bunch of shots like this that I wanna show you.

This is a fire ant worker on my finger.

Her stings starts with a bite.

The worker sinks her mandibles into my skin.

Then she starts to probe around for a place to insert her stinger.

The stinger is at the tip of the abdomen.

If we zoom in to just a stinger in this shot you can see a droplet of venom form.

When this thing lands, it is pushed out of the sting shaft.

An average fire ant worker has a reservoir containing around 30 nanoliters of venom connected to their sting.

Though dosage can vary between ants, a typical sting injects around 0.7 nanoliters of venom.

Fire and stingers are not as heavily barbed as honeybees.

So after venom injection, the ant can walk away pulling her stinger out, continuing on unharmed and able to sting again.

After I captured those sequences I noticed in this shot here where the little droplet of venom is forming, it looks like you can see what the stinger is doing to actually pump out venom.

That's really interesting to me because no one's ever filmed ant stingers in that amount of detail before.

So I set out to capture more of those shots and capture what actually happens when an ant is delivering venom.

This is a stinger of an ant piercing a thin wax film and pumping venom.

It's filmed in slow motion at a thousand frames per second.

I think I know why no one's been able to film this before because ant stingers in the parts that are moving are really tiny and really fast For scale, here's the stinger of a harvester ant.

The stinger is about 40 microns wide.

That's smaller than the width of a human hair.

Stingers are made up of three parts, a stylet and a pair of lancets.

In some ants like the harvester ants, the tips of the lancets are barbed while others like this trap jaw ant stinger are smooth and more needle-like.

When an ant inserts its stinger into something, the lancets are in motion, sliding back and forth beyond the tip of the stylet.

This movement helps the stinger drill deeper into its target but also it's what pumps the venom out of the stinger.

From analyzing these clips, it takes an average of 75 milliseconds for a lancet to move back and forth.

That's faster than the blink of an eye which takes about 80 milliseconds.

So in just one second, an ant can deliver 13 droplets of venom even more if the back and forth movements if the two lancets overlap.

So that was a lot about stinging, but fire ants do more than that.

And I wanna show you one more incredible collective group behavior they do called rafting.

To do that, I set up a colony in soil at the bottom of a bucket like this.

If you slowly drip water on the colony over a course of a day it simulates heavy rain and a flooding event.

In response to a flood, the entire colony will emerge from the ground carrying their eggs larvae and pupae.

As the water levels rise, the ants cling to each other forming a living raft that their nest mates gather on.

They can float like this as a colony for days until floodwaters recede and they reach higher ground.

Fire ants evolve the ability to raft because they're native to flood plains in Argentina.

Here in North Carolina, you can see them rafting too after a hard rain or even a hurricane.

So despite being pest ants, I think fire ants do some incredible things.

And hey, at least after watching this, the next time you're stung by an ant, you know exactly how it's doing it.

[upbeat music] - And that's it for SCI NC.

I'm Frank Graff.

Thank you for watching.

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- [Narrator] Funding for the SCI NC series is provided by GSK.