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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The mystery of why life uses molecules with specific orientations has deepened with a NASA-funded discovery that RNA — a key molecule thought to have potentially held the instructions for life before DNA emerged — can favor making the building blocks of proteins in either the left-hand or the right-hand orientation. Resolving this mystery could provide clues to the origin of life. The findings appear in research recently published in Nature Communications.
Proteins are the workhorse molecules of life, used in everything from structures like hair to enzymes (catalysts that speed up or regulate chemical reactions). Just as the 26 letters of the alphabet are arranged in limitless combinations to make words, life uses 20 different amino acid building blocks in a huge variety of arrangements to make millions of different proteins. Some amino acid molecules can be built in two ways, such that mirror-image versions exist, like your hands, and life uses the left-handed variety of these amino acids. Although life based on right-handed amino acids would presumably work fine, the two mirror images are rarely mixed in biology, a characteristic of life called homochirality. It is a mystery to scientists why life chose the left-handed variety over the right-handed one.
A diagram of left-handed and right-handed versions of the amino acid isovaline, found in the Murchison meteorite.NASA DNA (deoxyribonucleic acid) is the molecule that holds the instructions for building and running a living organism. However, DNA is complex and specialized; it “subcontracts” the work of reading the instructions to RNA (ribonucleic acid) molecules and building proteins to ribosome molecules. DNA’s specialization and complexity lead scientists to think that something simpler should have preceded it billions of years ago during the early evolution of life. A leading candidate for this is RNA, which can both store genetic information and build proteins. The hypothesis that RNA may have preceded DNA is called the “RNA world” hypothesis.
If the RNA world proposition is correct, then perhaps something about RNA caused it to favor building left-handed proteins over right-handed ones. However, the new work did not support this idea, deepening the mystery of why life went with left-handed proteins.
The experiment tested RNA molecules that act like enzymes to build proteins, called ribozymes. “The experiment demonstrated that ribozymes can favor either left- or right-handed amino acids, indicating that RNA worlds, in general, would not necessarily have a strong bias for the form of amino acids we observe in biology now,” said Irene Chen, of the University of California, Los Angeles (UCLA) Samueli School of Engineering, corresponding author of the Nature Communications paper.
In the experiment, the researchers simulated what could have been early-Earth conditions of the RNA world. They incubated a solution containing ribozymes and amino acid precursors to see the relative percentages of the right-handed and left-handed amino acid, phenylalanine, that it would help produce. They tested 15 different ribozyme combinations and found that ribozymes can favor either left-handed or right-handed amino acids. This suggested that RNA did not initially have a predisposed chemical bias for one form of amino acids. This lack of preference challenges the notion that early life was predisposed to select left-handed-amino acids, which dominate in modern proteins.
“The findings suggest that life’s eventual homochirality might not be a result of chemical determinism but could have emerged through later evolutionary pressures,” said co-author Alberto Vázquez-Salazar, a UCLA postdoctoral scholar and member of Chen’s research group.
Earth’s prebiotic history lies beyond the oldest part of the fossil record, which has been erased by plate tectonics, the slow churning of Earth’s crust. During that time, the planet was likely bombarded by asteroids, which may have delivered some of life’s building blocks, such as amino acids. In parallel to chemical experiments, other origin-of-life researchers have been looking at molecular evidence from meteorites and asteroids.
“Understanding the chemical properties of life helps us know what to look for in our search for life across the solar system,” said co-author Jason Dworkin, senior scientist for astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and director of Goddard’s Astrobiology Analytical Laboratory.
Dworkin is the project scientist on NASA’s OSIRIS-REx mission, which extracted samples from the asteroid Bennu and delivered them to Earth last year for further study.
“We are analyzing OSIRIS-REx samples for the chirality (handedness) of individual amino acids, and in the future, samples from Mars will also be tested in laboratories for evidence of life including ribozymes and proteins,” said Dworkin.
The research was supported by grants from NASA, the Simons Foundation Collaboration on the Origin of Life, and the National Science Foundation. Vázquez-Salazar acknowledges support through the NASA Postdoctoral Program, which is administered by Oak Ridge Associated Universities under contract with NASA.
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Last Updated Nov 21, 2024 EditorWilliam SteigerwaldContactNancy N. Jonesnancy.n.jones@nasa.govLocationGoddard Space Flight Center Related Terms
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By NASA
Linda Spuler, emergency manager at NASA’s Johnson Space Center in Houston, believes that everyone has a story. “Our stories highlight what we have in common, but they also make us each unique,” she said.
Spuler has worked at Johnson for over 32 years, spending most of her career in Center Operations. Her story has involved helping to coordinate emergency response teams at Johnson in preparation for natural disasters. “Since Johnson is situated on the coast, a good portion of my job revolves around planning for hurricanes,” she said.
Spuler has dealt with natural disasters at Johnson from Tropical Storm Allison in 2001 to Hurricane Beryl in 2024, but none had a greater personal impact than Hurricane Ike, which wrought havoc in Texas in September 2008. “Participating in the response to Hurricane Ike was a proud moment for me,” she said. “We worked from sunup to sundown restoring the center. Civil servants and contractors from various organizations came together, and for those two weeks, our differences didn’t matter.”
NASA’s Johnson Space Center Emergency Manager Linda Spuler, front, leads an emergency exercise for first responders. Image courtesy of Linda Spuler Spuler believes that NASA’s mission unites everyone – team members, astronauts, and support teams alike. “Remembering why we are all here energizes us and gets us excited about working for NASA,” she said.
Spuler’s journey at NASA began as a dream not originally her own. Her path was shaped by the aspirations of her mother, who was born on an Ojibwe (Chippewa) reservation in Ashland, Wisconsin.
“Although my grandmother lived in Chicago, she returned to the reservation to have her children. My mom is still a voting member of the Bad River Tribe,” said Spuler.
“My mom was studying aerospace engineering at the University of Chicago when she met my dad, a fun-loving electrical engineering major who traced his lineage back to Davy Crockett on his father’s side and Ireland on his mother’s,” said Spuler. “She chose to abandon aerospace to marry my dad, whose degree and love for space brought him to work at Johnson.”
Linda Spuler accepts the Thirty-Year Service Award from Johnson Director Vanessa Wyche to commemorate her service at NASA. NASA/David DeHoyos Spuler said her mother was very proud that her father worked for NASA. “She was very happy when I chose to work here, too,” she said. “She taught me the value and reward of working hard. My mom is proud of her heritage but she is cautious of sharing her story.”
Linda Spuler at an Easter egg hunt at NASA’s Johnson Space Center in 1971. Image courtesy of Linda Spuler Spuler enjoys learning about Ojibwe culture from her mother. “Every Thanksgiving, we enjoy wild rice from the Bad River sent from the “aunties” that still live on the reservation,” Spuler shared. She also represents her culture and pride through her work, honoring the legacy of those who came before her and sharing the story of her mother, her father, and now herself.
Linda Spuler receives the 2019 Furlough Heroes Awards alongside her son, Logan. NASA/James Blair “I celebrate the unique story that makes me part Ojibwe, part Polish, part Texas revolutionary, part Irish, part English, and all me,” she said.
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By NASA
Citizen science projects enabled by data from the WISE and NEOWISE missions have given hundreds of thousands around the world the opportunity to make new discoveries. The projects can be done by anyone with a laptop and internet access and are available in fifteen languages. No U.S. citizenship required. NASA’s NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) spacecraft re-entered and burned up in Earth’s atmosphere on Friday night, as expected. Launched in 2009 as the WISE mission, the spacecraft has been mapping the entire sky at infrared wavelengths over and over for nearly fifteen years. During that time, more than one hundred thousand amateur scientists have used these data in citizen science projects like the Milky Way Project, Disk Detective, Backyard Worlds: Planet 9, Backyard Worlds: Cool Neighbors, and Exoasteroids.
This citizen science work has led to more than 55 scientific publications. Highlights include:
The discovery of Yellowballs, a kind of compact star-forming region. The discovery of Peter Pan Disks, long lived accretion disks around low-mass stars. The discovery of the first extreme T subdwarfs. The likely discovery of an aurora on a brown dwarf. Measurement of the field substellar mass function down to effective temperature ~400 K. The discovery of the oldest known white dwarf with a disk. Detection of a possible collision between planets. The discovery of the lowest-mass hypervelocity star. Although the spacecraft is no longer in orbit, there is plenty of work to do. The WISE/NEOWISE data contain trillions of detections of astronomical sources – enough to keep projects like Disk Detective, Backyard Worlds: Planet 9, Backyard Worlds: Cool Neighbors, and Exoasteroids busy making new discoveries for years to come. Join one of these projects today to help unravel the mysteries of the infrared universe!
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Last Updated Nov 04, 2024 Related Terms
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By NASA
Flight Engineer Joe Acaba holds a children’s book that he is reading from as part of the Story Time From Space program. Astronauts read aloud from a STEM-related children’s book while being videotaped and demonstrate simple science concepts and experiments aboard the International Space Station. Stories open up new worlds and spark curiosity in readers of all ages – and NASA is using the power of storytelling to encourage the Artemis Generation to explore STEM (science, technology, engineering, and mathematics). Through the below list of reading resources – books, comics, and graphic novels written and illustrated by NASA experts, and video read-alongs by astronauts – students will find themselves exploring the Moon, piloting a cutting-edge aircraft, searching for life among the stars, and more.
Come along with NASA on a journey of discovery!
Story Time With NASA Astronauts (Grades Pre-K to 4)
Take your reading adventure out of this world! In this video playlist, astronauts read storybooks aloud from aboard the International Space Station and other locations around NASA.
Kids Club Picture Show (Grades Pre-K to 4)
View cool pictures from NASA missions and more! This curated collection of fascinating photos introduces young explorers to a variety of topics across NASA. Each photo includes a short description with the option to hear it read aloud.
Astro-Not-Yet Storybooks (Grades K-4)
These storybooks follow along as an ambitious classroom of students learn about the International Space Station, NASA’s Commercial Crew Program, and important STEM concepts such as microgravity and sound waves. The books are available in English and Spanish.
The Adventures of Kennedy and Duke Storybook (Grades K-4)
This book follows the experiences of Kennedy, a fictional young girl who discovers an amateur radio during a visit to her grandfather’s farm. While learning to use the radio, she communicates with Duke, an astronaut living and working aboard the International Space Station. Also available in Spanish.
You Are Going, illustrated by former NASA intern Shane Tolentino, shares a glimpse into future Artemis missions. You Are Going (Grades K-4 and 5-8)
Through “You Are Going,” readers get a glimpse into NASA’s Artemis campaign. Learn about NASA’s powerful megarocket, the SLS (Space Launch System), as well as the Orion spacecraft, the Gateway, and other important elements that will help make these pioneering flights possible. Also available in Spanish and French.
Hooray For SLS (Grades K-4)
NASA is working to send humans back to the Moon to live, learn, and explore through the Artemis campaign – and as members of the Artemis Generation, today’s students are invited to be part of the story. “Hooray for SLS!” is the first in a series of children’s books introducing young explorers ages 3 to 8 to the SLS rocket and other components of the Artemis missions.
The Adventures of Commander Moonikin Campos and Friends Comics (Grades K-4 and 5-8)
Although no astronauts flew around the Moon on the Artemis I mission, the mission included a crew of manikins – Commander Moonikin Campos and two identical manikin torsos – outfitted with sensors to capture data during the flight. This webcomic explains what the manikins experienced on the Artemis I mission around the Moon. Also available in Spanish.
During World War II the United States Army Air Corps created the first fighter squadron in its history made up of Black military pilots. They became known as the Tuskegee Airmen. Their success in war overseas, and challenges faced at home, helped light the path toward equal rights for all. Aeronautics Leveled Readers (Grades K-4, 5-8, and 9-12)
The history of American aviation comes to life through these stories written at elementary, middle school, and high school levels. Students will read about important figures in aviation such as Amelia Earhart and the Tuskegee Airmen, as well as mini biographies of NASA employees Danielle Koch, Maria Cabellero, and Red Jensen.
Ruby Flottum reads the first issue of NASA’s “First Woman” graphic novel, entitled “Dream to Reality,” on Monday, July 25, 2022 at AirVenture at Oshkosh. First Woman Graphic Novels (Grades 5-8, 9-12, and Higher Education)
This graphic novel series takes readers into the world of fictional astronaut Callie Rodriguez, the first woman to explore the Moon. Build on the story’s lessons with the accompanying hands-on activities and videos designed for use in K-12 informal education settings. Also available in Spanish.
Astrobiology Graphic Novels (Grades 5-12)
Produced within NASA’s Astrobiology Program, “Astrobiology” is a graphic novel series that explores the many facets of astrobiology: the study of the origin, evolution, and distribution of life in the universe. Some novels are also available in Japanese, Korean, or Spanish editions.
Explore Further
There’s more to explore! Check out NASA’s STEM Search for additional resources for each grade level, including hands-on activities, games, educator guides, and more. Visit NASA’s Learning Resources for the latest news and resources from the agency’s Office of STEM Engagement.
Keep Exploring Discover More STEM Topics From NASA
Outside the Classroom
For Educators
For Kids and Students
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