Tag: SMU Department of Chemistry

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KERA: The Bright Side And Dark Side Of Blue Light

“We’re introducing blue light into the environment and into our daily lives at times when we’re not supposed to see it – and that basically causes dysfunction in our biological processes.” — Brian Zoltowski

KERA Public Radio journalist Justin Martin explored the good and bad of blue light in our environment with Brian Zoltowski, an assistant professor in the SMU Department of Chemistry.

“As a society, we are using more technology, and there’s increasing evidence that artificial light has had a negative consequence on our health,” says Zoltowski, who was awarded $320,500 from the National Institute of General Medical Sciences of the National Institutes of Health to continue its research on the impact of blue light.

“Our study uses physical techniques and chemical approaches to probe an inherently biological problem,” Zoltowski said. “We want to understand the chemical basis for how organisms use light as an environmental cue to regulate growth and development.”

Martin’s interview with Zoltowski, “The Bright Side And Dark Side Of Blue Light,” was published online Dec. 8.

Listen to the interview.

EXCERPT:

By Justin Martin
KERA
Light is necessary for life on earth, but scientists believe that too much of a certain wavelength can cause everything from crop diseases to changes in the migratory patterns of animals. SMU professor Brian Zoltowski is working to unravel the mystery of blue light in a study funded by the National Institutes of Health.

Interview Highlights: Brian Zoltowski

… On what defines blue light:

“Blue light refers to a part of the electromagnetic spectrum that has specific energy. Usually we define things by basically their wavelength of light. So typically blue light can be centered around 450 nanometers but can range … from about 425 nanometers to 475 nanometers.”

… On the origin of excess blue light:

“Blue light is very abundant in nature in general. That’s why organisms actually use that wavelength of light to drive their biological processes. But it turns out though that because it’s abundant in nature, we like to have it to be abundant in our products like our lights, our computers, our laptops and everything else. So we introduce a lot more foreign blue light into the environment compared to what should naturally be there.”

… On blue light’s effects in animals vs. plants:

“A lot of that is not known, which is one of the reasons we’re actually doing a lot of this research. What we do know is that blue is extremely important for basically growth and development of any organism you can conceive of. How that’s ultimately regulated and when there can be too much is a big question. The bigger question is when you get the blue light, nature is designed to use blue light as a signal as to what time of day it is. So when we’re introducing blue light into the environment or into our daily lives through computers and laptops, we’re introducing blue light at times of day like evening when we’re not supposed to see it – and that basically causes dysfunction in our biological processes.”

… On how blue light fosters fungal growth:

“There’s growing understanding that a lot of these fungal pathogens of plants – there are several that actually attack wine, which causes billions of dollars of crop loss each year. There are some that we’re interested in that also basically attack a lot of your grain crops — so you’re looking at wheat, alfalfa — that have very detrimental aspects to agriculture. Their ability to infect the plant is regulated by blue light.”

Listen to the interview.

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Study funded by NIH is decoding blue light’s mysterious ability to alter body’s natural clock

Blue light from artificial lighting and electronic devices knocks circadian rhythms off-kilter, resulting in health problems, sleep, cancer development, mood disorders, drug addiction, crop disease and even confused migratory animals

A study funded by the National Institutes of Health is unraveling the mystery of how blue light from residential and commercial lighting, electronic devices and outdoor lights can throw off-kilter the natural body clock of humans, plants and animals, leading to disease.

Exposure to blue light is on the increase, says chemist Brian D. Zoltowski, Southern Methodist University, Dallas, who leads the study, “Protein : Protein interaction networks in the circadian clock.”

At the right time of day, blue light is a good thing. It talks to our 24-hour circadian clock, telling our bodies, for example, when to wake up, eat and carry out specific metabolic functions.

In plants, blue light signals them to leaf out, grow, blossom and bloom. In animals, it aids migratory patterns, sleep and wake cycles, regulation of metabolism, as well as mood and the immune system.

But too much blue light — especially at the wrong time — throws biological signaling out of whack.

“As a society, we are using more technology, and there’s increasing evidence that artificial light has had a negative consequence on our health,” said Zoltowski, an assistant professor in SMU’s Department of Chemistry.

“Our study uses physical techniques and chemical approaches to probe an inherently biological problem,” he said. “We want to understand the chemical basis for how organisms use light as an environmental cue to regulate growth and development.”

Zoltowski’s lab was awarded $320,500 from the National Institute of General Medical Sciences of the National Institutes of Health to continue its research on the impact of blue light.

The lab studies a small flowering plant native to Europe and Asia, Arabidopsis thaliana. The flower is a popular model organism in plant biology and genetics, Zoltowski said.

Although signaling pathways differ in organisms such as Arabidopsis when compared to animals, the flower still serves an important research purpose. How the signaling networks are interconnected is similar in both animals and Arabidopsis. That allows researchers to use simpler genetic models to provide insight into how similar networks are controlled in more complicated species like humans.

Understanding the mechanism can lead to targeted drug treatments
In humans, the protein melanopsin absorbs blue light and sends signals to photoreceptor cells in our eyes. In plants and animals, the protein cryptochrome performs similar signaling.

Much is known already about the way blue light and other light wavelengths, such as red and UV light, trigger biological functions through proteins that interact with our circadian clock. But the exact mechanism in that chemical signaling process remains a mystery.

“Light is energy, and that energy can be absorbed by melanopsin proteins that act as a switch that basically activates everything downstream,” Zoltowski said.

Melanopsin is a little-understood photoreceptor protein with the singular job of measuring time of day.

When light enters the eye, melanopsin proteins within unique cells in the retina absorb the wavelength as a photon and convert it to energy. That activates cells found only in the eye — called intrinsically photosensitive retinal ganglian cells, of which there are only about 160 in our body. The cells signal the suprachiasmatic nucleus region of the brain.

“We keep a master clock in the suprachiasmatic nucleus — it controls our circadian rhythms,” he said. “But we also have other time pieces in our body; think of them as watches, and they keep getting reset by the blue light that strikes the master clock, generating chemical signals.”

The switch activates many biological functions, including metabolism, sleep, cancer development, drug addiction and mood disorders, to name a few.

“There’s a very small molecule that absorbs the light, acting like a spring, pushing out the protein and changing its shape, sending the signal. We want to understand the energy absorption by the small molecule and what that does biologically.”

The answer can lead to new ways to target diabetes, sleep disorders and cancer development, for example.

“If we understand how all these pathways work,” he said, “we can design newer, better, more efficacious drugs to help people.”

Chemical signal from retina’s “atomic clock” synchronizes circadian rhythms
Besides increased reliance on artificial lighting indoors and outdoors, electronic devices also now contribute in a big way to blue light exposure. Endless evening hours on our smartphones and tablets with Candy Crush, Minecraft or Instagram don’t really help us relax and go to sleep. Just the opposite, in fact.

The blue glow those devices emit signals our circadian clock that it’s daytime, Zoltowski said. Red light, on the other hand, tells us to go to sleep.

Awareness of the problem has prompted lighting manufacturers to develop new lighting strategies and products that transition blue light to red light toward evening and at night, Zoltowski said.

Targeted solutions could neutralize destructive blight in staple crops
In plants, the researchers study how the absence of “true dark” in nature due to artificial light can reduce yields of farm crops and promote crop disease.

For example, fungal systems rely on blue light to proliferate, forming pathogens known as blight in crops resulting in leaves that look chewed on and reducing yields.

“We study fusarium and verticillium,” Zoltowski said. “They cause about $3 billion worth of crop damage a year to wheat, corn, soybeans — the staple food crops.”

Understanding their ability to infect crops would allow scientists to potentially design small molecules that target and disrupt the fungal system’s circadian clock and neutralize their proliferation.

Research to understand how light and clock regulation are coupled
In animals, Zoltowski’s lab studies the blue light pathway that signals direction to birds and other animals that migrate. Blue light activates the protein that allows various species to measure the earth’s magnetic field for directionality. For example, Monarch butterflies rely on the cryptochrome photoreceptor for their annual migration to Mexico.

“We’re interested in how these pathways are regulated in a diverse range of organisms to understand how we can manipulate these pathways to our advantage,” he said, “for health consequences and to improve agriculture yields.”

The researchers will map the reaction trajectory beginning from the initial absorption of the photon to the point it alters an organism’s physiology.

Zoltowski notes that light is just one of a handful of external cues from our environment that trigger biological processes regulating the circadian clock. Others include temperature changes, feeding and metabolites.

Besides the NIH grant, the lab operates with $250,000 from the American Chemical Society’s Herman Frasch Foundation for Chemical Research Grants in Agricultural Chemistry. — Margaret Allen

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Scientific American: How your smartphone messes with your brain — and your sleep

Scientific American science blogger Josh Fischman drew on the sleep expertise of SMU Assistant Professor of Chemistry Brian D. Zoltowski to explain how artificial light from our smartphones and other digital devices causes sleep deprivation. His blog article, “How your smartphone messes with your brain — and your sleep,” published May 20 and has been heavily shared through social media.

Zoltowski’s lab at SMU studies one of the many proteins involved in an organism’s circadian clocks. Called a photoreceptor, the protein responds to light to predict time of day and season by measuring day length.

The circadian clock is an internal biological mechanism that responds to light, darkness and temperature in a natural 24-hour biological cycle. The clock synchronizes body systems with the environment to regulate everything from sleep patterns and hunger in humans to growth patterns and flowering in plants.

“Our research focuses on understanding the chemical basis for how organisms perceive their surroundings and use light as an environmental cue to regulate growth and development,” Zoltowski says.

Zoltowski and the American Chemical Society created a video explaining the light-sleep deprivation relationship.

Read the full story.

EXCERPT:

By Josh Fischman
Scientific American
It’s not the Angry Birds, streaming videos, emails from your boss, or your Facebook updates that disturb your sleep when you spend an evening staring at your smartphone or tablet. OK, the apps can keep you glued to your screen until the wee hours, and that doesn’t help. But it is the specific type of light from that screen that is throwing off your natural sleep-wake cycles, even after you power down. In a new video from Reactions: Everyday Chemistry, a sleep researcher explains the eerie power of blue light over your brain.

Cells at the back of your eyes pick up particular light wavelengths and, with a light-sensitive protein called melanopsin, signal the brain’s master clock, which controls the body’s circadian rhythms. Blue light, which in nature is most abundant in the morning, tells you to get up and get moving. Red light is more common at dusk and it slows you down. Now, guess what kind of light is streaming from that little screen in your hand at 11:59 P.M.? “Your iPad, your phone, your computer emit large quantities of blue light,” says sleep researcher and chemist Brian Zoltowski of Southern Methodist University

Read the full story.

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Business Insider: Your Smartphone Is Destroying Your Sleep

Business Insider Science Editor Jennifer Walsh tapped the sleep expertise of SMU Assistant Professor of Chemistry Brian D. Zoltowski to explain how artificial light from our smartphones and other digital devices causes sleep deprivation. Her article, “Your Smartphone Is Destroying Your Sleep,” published May 19.

Zoltowski’s lab at SMU studies one of the many proteins involved in an organism’s circadian clocks. Called a photoreceptor, the protein responds to light to predict time of day and season by measuring day length.

The circadian clock is an internal biological mechanism that responds to light, darkness and temperature in a natural 24-hour biological cycle. The clock synchronizes body systems with the environment to regulate everything from sleep patterns and hunger in humans to growth patterns and flowering in plants.

“Our research focuses on understanding the chemical basis for how organisms perceive their surroundings and use light as an environmental cue to regulate growth and development,” Zoltowski says.

Zoltowski and the American Chemical Society created a video explaining the light-sleep deprivation relationship.

Read the full story.

EXCERPT:

By Jennifer Welsh
Business Insider
Artificial light is one of the biggest causes of sleep deprivation in modern humans, but there’s some special witch magic in smartphone and tablet light that really messes with our sleep cycle — essentially forcing us to stay awake by convincing our bodies that it’s actually morning.

Smartphones do this because they let off bright blue light.

“One of the best biological cues we have to what time of day it is is light. And it turns out that blue light in particular is very effective at basically predicting when morning is,” chemistry researcher Brian Zoltowski says in the video below, from the American Chemical Society.

In the evenings, there’s more red light than blue light, which signals your body to prep for bed. The red light does this by interacting with the protein melanopsin in cells deep inside your eyes — ones that are specifically made to regulate circadian rhythms and don’t play a role in how we see.

When the light hits this protein, it changes, and these cells send a signal to the “master clock” of the brain, which dictates when we wake and when we get sleepy. When it sends a “wake up” signal at night, our body clock gets screwed up.

The solution to a screwed up body clock? Force yourself to do things at the right time of the day — eating at mealtimes, getting to bed at a normal time, and getting up at a good time as well. And, of course, avoid that blue light at night.

Read the full story.

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Chemical probe confirms that body makes its own rotten egg gas, H2S, to benefit health

Chemists develop chemical probe to help scientists study mechanics of critical signaling molecules, such as H2S, and to study how hydrogen sulfide benefits cardiovascular health

A new study confirms directly what scientists previously knew only indirectly: The poisonous “rotten egg” gas hydrogen sulfide is generated by our body’s growing cells.

Hydrogen sulfide, or H2S, is normally toxic, but in small amounts it plays a role in cardiovascular health.

In the new study, chemists developed a chemical probe that reacts and lights up when live human cells generate hydrogen sulfide, says chemist Alexander R. Lippert, Southern Methodist University, Dallas. The discovery allows researchers to observe the process through a microscope.

The researchers captured on video the successful chemical probe at work, said Lippert, an assistant professor in the SMU Department of Chemistry.

“We made a molecular probe that, when it reacts with hydrogen sulfide, forms a fluorescent compound that can be visualized using fluorescence microscopy,” Lippert said. “This is the first time that endogenously generated hydrogen sulfide has been directly visualized in a living system. This confirms a lot of hypotheses that scientists have, but no one had the tools to directly detect it in real time.”

H2S is one of several small gaseous molecules increasingly recognized as key signaling molecules in the body. For example, H2S helps reduce high blood pressure. Scientists discovered in the past decade that cells in the human body generate small quantities of H2S molecules, which in turn deliver information to proteins. The proteins act on the information to perform critical functions in the body.

Previously, scientists couldn’t observe H2S being generated in live cells. As a result, researchers faced challenges when studying hydrogen sulfide in living systems, Lippert said. The new discovery now provides a tool to view directly how and when hydrogen sulfide is generated, he said. Lippert and study co-author chemist Vivian S. Lin made the discovery.

Discovery provides research tool for scientists to observe H2S in live cells
“Having the tools to do this in living systems is going to open up a lot of possibilities and experiments for scientists,” Lippert said. “As a tool, this will allow researchers to ask questions that weren’t possible before.”

Lippert’s real-time video features live human cells, taken from the lining of blood vessels and treated with the chemical probe and with a protein known to promote cell growth. Once the cells start generating H2S, they behave like squiggly fluorescent green worms.

The researchers’ scientific article, “Cell-trappable fluorescent probes for endogenous hydrogen sulfide signaling and imaging H2O2-dependent H2S production,” was published online in the Proceedings of the National Academy of Sciences.

Lippert and Lin authored the research with Christopher J. Chang, principal investigator. Lin is a PhD candidate at the University of California at Berkeley. Chang is with the Howard Hughes Medical Institute, University of California at Berkeley. Lippert and Lin carried out the research in Chang’s UC Berkeley laboratory.

Discovery can help scientists attack diseases such as cancer
H2S — along with nitric oxide, carbon monoxide and others in this emerging class of gaseous signaling molecules — assists the body’s large proteins.

Large proteins do much of the functional work in the body, such as digesting the food we eat and harnessing the energy in the oxygen we breathe. Their size, however, forces them to move slowly inside the cell. In contrast, H2S and other small gaseous molecules diffuse quickly and easily across cellular membranes, enabling them to travel much faster and rapidly deliver information that mediates critical functions, such as blood pressure regulation, Lippert said.

For their experiments, Lippert and Lin placed living endothelial cells cultured from the internal lining of a blood vessel into a petri dish under a microscope.

Lippert and Lin then added a chemical solution containing an azide-functionalized organic molecule that they’d synthesized to act as a molecular probe. They gave the cells time to absorb the probe, then added a protein solution known to stimulate blood vessel formation. As the cells initiated blood vessel formation, H2S was generated. In reaction, the scientists observed a steady increase in the probe’s fluorescence.

“Essentially we’re observing the initial events that lead to the building of new blood vessels, a process that’s active in babies as they develop, or in women during their menstruation cycles,” Lippert said. “We see the cells get really bright as they start moving around and ruffling their membranes. That’s the H2S being formed. In the control group, which weren’t stimulated with the growth protein, they don’t get any brighter and they don’t move around.”

The discovery provides new insights that can help scientists attack diseases, such as cancer, by starving the nutrient supply to a tumor, Lippert said.

“When tumors grow they need a lot of blood support because they need the nutrients to support their rapid growth,” he said. “If you can stop blood vessel formation you could starve the tumor and the tumor will die. So inhibiting H2S formation might be a way to treat cancer using this method.” — Margaret Allen