Wednesday, January 8, 2020

'Bilingual' molecule connects two basic codes for life

The new molecule holds the potential for diverse biomedical applications, says Emory chemist Jennifer Heemstra (right), senior author of the paper. She is shown in her lab with graduate student Colin Swenson, first author of the paper. (Photo by Kay Hinton)

By Carol Clark

The nucleic acids of DNA encode genetic information, while the amino acids of proteins contain the code to turn that information into structures and functions. Together, they provide the two fundamental codes underlying all of life.

Now scientists have found a way to combine these two main coding languages into a single “bilingual” molecule.

The Journal of the American Chemical Society published the work by chemists at Emory University. The synthesized molecule could become a powerful tool for applications such as diagnostics, gene therapy and drug delivery targeted to specific cells.

“Much like a translator enables communication between two people from different regions of the world, we envision that our bilingual molecule will enable us to mediate new forms of communications between nucleic acids and proteins in the cellular environment,” says Jennifer Heemstra, associate professor of chemistry at Emory University and senior author of the study. 

Nucleic acids store information in an “alphabet” of four bases, known as nucleotides. Peptides and proteins use an entirely different alphabet, made up of 20 different amino acids.

“The nucleic acid language is easy to speak, but kind of limited,” Heemstra says. “While the protein language is incredibly complex and difficult to predict. Both of these molecules have developed exquisite properties over billions of years of evolution.”

Previously synthesized molecules have focused on the properties of either nucleic acids or amino acids. The Emory researchers wanted to harness the powers of both information systems within a single molecule.

The challenge was enormous, drawing on techniques from organic chemistry, molecular and cellular biology, materials science and analytical chemistry. The researchers built a protein scaffold and then attached functioning fragments of nucleotides and amino acids to this framework.

“The two different codes needed to be synthesized separately and then brought together into the scaffold,” says Colin Swenson, first author of the paper and a graduate student in the Heemstra Lab.

The resulting bilingual molecule is stable, made of inexpensive materials, and highly generalizable, giving it the potential for diverse biomedical and nanotechnology applications. “It’s like a programmable, universal adaptor that brings proteins and nucleic acids together,” Heemstra says. “We hope that other researchers are inspired to think about different ways that it might be applied.” 

The Emory chemists are now exploring using the bilingual molecule for targeted drug delivery to particular cells. “It’s essentially a stimuli-sensitive container,” Heemstra says. “We’ve demonstrated that it can bind to drug molecules. And it’s programmable to fall apart in the presence of specific RNA molecules that are more abundant in cancer cells.”

Related:
Chemists teach old drug new tricks to target deadly staph bacteria
DNA 'origami' takes flight in emerging field of nano machines

Wednesday, December 18, 2019

Dogs process numerical quantities in similar brain region as humans

Emory neuroscientist Gregory Berns is researching how dogs think and view the world. (Photo by Kay Hinton)

Dogs spontaneously process basic numerical quantities, using a distinct part of their brains that corresponds closely to number-responsive neural regions in humans, finds a study at Emory University.

Biology Letters published the results, which suggest that a common neural mechanism has been deeply conserved across mammalian evolution.

“Our work not only shows that dogs use a similar part of their brain to process numbers of objects as humans do — it shows that they don’t need to be trained to do it,” says Gregory Berns, Emory professor of psychology and senior author of the study.

“Understanding neural mechanisms — both in humans and across species — gives us insights into both how our brains evolved over time and how they function now,” says co-author Stella Lourenco, an associate professor of psychology at Emory.

Such insights, Lourenco adds, may one day lead to practical applications such as treating brain abnormalities and improving artificial intelligence systems.

Lauren Aulet, A PhD candidate in Lourenco's lab, is first author of the study.

Read the full story here.

Related:
Scientists chase mystery of how dogs process words
Do dogs prefer praise or food?
Scent of the familiar: You may linger like perfume in your dog's brain

Friday, December 13, 2019

Emory soil analysis project leads to EPA site investigation

Emory professor Eri Saikawa (left) in the field with Historic Westside Gardens member and Westside resident Rosario Hernandez (center) and Xinyi Yao (right), an Emory student pursuing a master's degree in environmental sciences who is involved in the research project. (Photo by Carol Clark)

An Emory University collaboration with members of Atlanta’s Westside community, to test urban soil for contaminants, has led to a site investigation by the U.S. Environmental Protection Agency (EPA). The ongoing community collaboration is funded by Emory’s HERCULES Exposome Research Center, dedicated to understanding how environmental exposures affect health and community well-being.

The EPA told the Atlanta Journal-Constitution that it is continuing to collect samples and has so far identified 64 sites where the soil contains elevated levels of lead — a dangerous neurotoxin. The agency plans to begin decontaminating properties, possibly by removing and replacing soil, in the first quarter of next year, at no expense to residents or homeowners, according to the AJC. The report also appeared in Georgia Health News.

“It’s important for people to know that soil contamination by heavy metals can be serious,” says Eri Saikawa, an associate professor of environmental sciences at Emory and the lead researcher on the original project that sparked the EPA investigation. “If you are thinking about gardening in an urban area, or if children are playing in your yard, it makes sense to test your soil and make sure that it’s not contaminated.”

Read the full story here.

Related:
Creating an atmosphere for change
The growing role of farming and nitrous oxide in climate change

Wednesday, December 4, 2019

What is a scream? The acoustics of a primal human call

Getty Images

Screams are prompted by a variety of emotions — from joyful surprise to abject terror. No matter what sparks them, however, human screams share distinctive acoustic parameters that listeners are attuned to, suggests a new study published by the Journal of Nonverbal Behavior.

“Screams require a lot of vocal force and cause the vocal folds to vibrate in a chaotic, inconsistent way,” says senior author Harold Gouzoules, a professor of psychology at Emory University. “Despite the inherent variation in the way that screams are produced, our findings show that listeners can readily distinguish a scream from other human calls. And we are honing in on how they make that distinction.”

Jay Schwartz is first author of the paper and Jonathan Engleberg is a co-author. They are both Emory PhD candidates in Gouzoules’ Bioacoustics Lab. Gouzoules began researching monkey screams in 1980, before becoming one of the few scientists studying human screams about 10 years ago. He is interested in the origins of screams and the role they played in human development.

“Animal screams occur almost always in the context of a fight or in response to a predator,” Gouzoules says. “Human screams happen in a much broader array of contexts, which makes them much more interesting.”

Gouzoules' Bioacoustics Lab has amassed an impressive library of high-intensity, visceral sounds — from TV and movie performances to the screams of non-actors reacting to actual events posted to online sites such as YouTube.

For the current study, the researchers presented 182 participants with a range of human calls. Some of the calls were screams of aggression, exclamation, excitement, fear or pain. Others calls included cries, laughter and yells.

The participants showed strong agreement for what classified as a scream. An acoustical analysis for the calls the participants classified as screams, compared to those they did not, included a higher pitch and roughness, or harshness, to the sound; a wider variability in frequency; and a higher peak frequency.

The current paper is part of an extensive program of research into screams by Gouzoules. In another recently published article, his lab has found that listeners cannot distinguish acted screams from naturally occurring screams. Listeners can, however, correctly identify whether pairs of screams were produced by the same person or two different people.

Related:
Screams contain a calling card for vocalizer's identity

Thursday, October 24, 2019

The psychology of thrills and chills

Monsters do not thrill psychologist Ken Carter, shown at Netherworld in Stone Mountain. Photo by Kay Hinton.

Psychologist Kenneth Carter is not a fan of Halloween haunted houses. But he has written a book about people who thrive on activities like entering dark passageways, sensing that something unknown and terrifying awaits around the next corner.

“I don’t enjoy having things come out of nowhere,” says Carter, whose long-anticipated book “Buzz! Inside the Minds of Thrill-Seekers, Daredevils and Adrenaline Junkies” comes out October 31. “Buzz!” both educates and entertains with insights from real-life adventurers, such as a scaler of skyscrapers, known as “Spider Man,” who enjoys hanging from great heights suspended by only his fingers.

Cambridge University Press is publishing the book, the culmination of years of research into high sensation-seeking people by Carter, a professor at Oxford College of Emory University and a self-described low sensation-seeking personality type.

“I love Halloween because it brings both extremes together, there’s something for everyone,” Carter says. “For me, it’s candy corn. That’s my second favorite candy, after Smarties. I enjoy the sweet, silly side of Halloween — not the dark, scary side. I don’t want to get lost in a corn maze or watch ‘The Children of the Corn.’”

Read the full story here.