The pale arch of light from the plane of our galaxy can be a humbling sight on a clear, dark night. But it’s just a sliver of all the treasures lurking in the Milky Way. Dense clouds of interstellar dust block visible light from remote regions of the galaxy but allow longer wavelengths to pass through. In February, astronomers completed a new map of our galaxy as seen in submillimeter light, which is shorter than radio waves but longer than infrared waves.
Submillimeter light can penetrate dust clouds, revealing details at the center of the galaxy and in stellar nurseries not visible at other wavelengths. The map was produced by ATLASGAL, a project using the APEX telescope in northern Chile to map part of the Milky Way. The project charted one-third of the band of galactic light that encircles our solar system; the images below show a narrow slice toward the constellation Sagittarius. Combined with images from the Spitzer and Planck satellites, the ATLASGAL map (top row) creates a detailed atlas of some of the cold structures in our galaxy. Dust clouds in places like the Trifid and Lagoon nebulas (circled, left), both a few thousand light-years away, glow faintly, as do filaments of detritus in the center of the galaxy (circled, right), 28,000 light-years from Earth. At near-infrared wave-lengths (center row), these regions nearly vanish behind obscuring curtains of dust. The galactic center remains hidden in visible light (bottom row) as well, though hot stars in Trifid and Lagoon radiate pools of hydrogen gas, making them glow.
A sugar that freshens air in rooms may also clean cholesterol out of hardened arteries.
The sugar, cyclodextrin, removed cholesterol that had built up in the arteries of mice fed a high-fat diet, researchers report April 6 in Science Translational Medicine. The sugar enhances a natural cholesterol-removal process and persuades immune cells to soothe inflammation instead of provoking it, say immunologist Eicke Latz and colleagues.
Cyclodextrin, more formally known as 2-hydroxypropyl-beta-cyclodextrin, is the active ingredient in the air freshener Febreze. It is also used in a wide variety of drugs; it helps make hormones, antifungal chemicals, steroids and other compounds soluble. If the new results hold up in human studies, the sugar may also one day be used to liquefy cholesterol that clogs arteries. Other researchers say the approach is promising, but must be tested in clinical trials. The sweet molecule is generally considered safe, but injecting it may raise the risk of liver damage or hearing loss, says Elena Aikawa, a vascular biologist at Brigham and Women’s Hospital in Boston.
Mice taking cyclodextrin in the study did not exhibit side effects from the treatment, but previous work has indicated that the sugar may damage hearing in mice and cats. The molecule shunts cholesterol through the liver, so large cholesterol influxes might cause fat to build up in the liver, impairing its function. “Overall, cyclodextrin seems worth exploring as a therapeutic, although caution should be taken,” Aikawa says.
Cyclodextrin works by flipping a master switch, a gene called LXR, Latz and colleagues found. LXR’s protein turns on other genes involved in processing cholesterol and ushering it out of the body. The sugar also activated the LXR genes in human arteries examined in the lab and turned on inflammation-calming processes, Latz’s team discovered.
Latz, of the University Hospital Bonn in Germany, credits Nevada businesswoman Chris Hempel with the idea to use cyclodextrin to treat atherosclerosis. In people with the condition, cholesterol, calcium, immune cells and other substances form plaques inside arteries, hardening them. Plaques block blood flow and can break away and cause heart attacks and strokes (SN: 2/20/16, p. 32).
Hempel has twin daughters with a rare genetic disease known as Niemann-Pick Type C, in which cholesterol crystals clog organs, especially the brain. In 2009, the girls got special permission from the Food and Drug Administration for their doctor to give them infusions of cyclodextrin to dissolve the cholesterol crystals. Hempel later read a paper by Latz and colleagues in which the researchers described how cholesterol crystals irritate macrophages and provoke them to cause inflammation and heart disease. Macrophages normally patrol the body and help kill invading bacteria, viruses and other pathogens. The immune cells also gobble up cholesterol and deliver it to the liver where it can be made into bile and escorted out of the body in feces.
Hempel e-mailed Latz and suggested that cyclodextrin might melt the cholesterol crystals in arteries. Latz and his colleagues tested the idea by feeding mice genetically prone to atherosclerosis a high-fat diet and giving the animals regular injections of cyclodextrin under the skin. The sugar kept cholesterol plaques from building up in the rodents’ arteries. The scientists also found that cyclodextrin reduced already established plaques in mice by about 45 percent, even though the animals were still eating a high-fat diet.
Cyclodextrin could be used in combination with other drugs, such as statins, says Eran Elinav, an immunologist at the Weizmann Institute of Science in Rehovot, Israel. Statins and other drugs inhibit cholesterol production. “Potentially, combining cholesterol lowering with dissolution of preformed cholesterol in plaques could be additive,” Elinav says, “but this option needs to be explored in clinical trials.”
Although cyclodextrin is already approved by the FDA for use in people, it may be years before it’s known whether injecting the sugar will soften people’s hardened arteries. The sugar is not patentable, so no pharmaceutical companies have come forward to sponsor expensive clinical trials needed to get approval for this specific use, Latz says.
All across the wrinkly expanse of the brain’s outer layer, a constellation of different regions handle the meaning of language, scientists report online April 27 in Nature.
One region that responds to “family,” “home” and “mother,” for example, rests in a tiny chunk of tissue on the right side of the brain, above and behind the ear. That region and others were revealed by an intricate new map that charts the location of hundreds of areas that respond to words with related meanings. Such a detailed map hints that humans comprehend language in a way that’s much more complicated — and involves many more brain areas — than scientists previously thought, says Stanford University neuroscientist Russell Poldrack, who was not involved in the work.
In fact, he says, “these data suggest we need to rethink how the brain organizes meaning.”
Scientists knew that different concepts roused action in different parts of the brain, says study coauthor Jack Gallant, a computational neuroscientist at the University of California, Berkeley. But people generally thought that big hunks of the brain each dealt with different concepts separately: one region for concepts related to vision, for example, another for concepts related to emotion. And conventional wisdom said the left hemisphere was most important.
Previous studies, though, tested just single words or sentences, and made only rough estimates of where meaning showed up in the brain, Gallant says. That’s like looking at the world’s countries in Google maps, instead of zooming in to the street view.
So he and colleagues mapped the activity of some 60,000 to 80,000 pea-sized regions across the brain’s outer layer, or cerebral cortex, as people lay in a functional MRI machine and listened to stories from The Moth Radio Hour. (The program features people telling personal, narrative tales to a live audience.) “People actually love this experiment,” Gallant says.
It stands out from others because the authors use “real life, complicated stories,” says Princeton University neuroscientist Uri Hasson. “That’s really meaningful to see how the brain operates.”
Gallant’s team used a computer program to decipher the meaning of every 1- to 2-second snippet of the stories and then cataloged where 985 concepts showed up in the brain. Meanings conveyed by different words didn’t just engage the left hemisphere, the team found, but instead switched on groups of nerve cells spread broadly across the brain’s surface. After mapping where meaning, or semantic content, was represented in the brain, the researchers figured out where individual words might show up. Often, the same word appeared in different locations. For instance, the word “top” turned up in a spot with clothing words, as well as in an area related to numbers and measurements.
The brain maps of the seven participants in the study looked remarkably similar, Gallant says. That could be due to common life experiences: All seven were raised and educated in Western societies. With so few people, the researchers can’t pick out any gender differences, he says, but ideally he’d like to repeat the experiment with 50 or 100 people.
For now, Gallant hopes the map can serve as a resource for other researchers. One day, the work could potentially help those with ALS or locked-in syndrome communicate — by decoding the words in a person’s thoughts. But that’s just one piece of the puzzle, Gallant says. Researchers would also need to devise a method for measuring brain activity that’s portable, unlike MRI machines.
Between around 6,000 and 4,000 years ago, skilled surgeons in southwestern Russia cut holes the size of silver dollars, or larger, out of the backs of people’s skulls. But the risky procedure wasn’t performed for medical reasons: These skull surgeries fulfilled purely ritual needs, a new study suggests. And those on the cutting end of the procedure usually lived.
Skulls of 13 people previously excavated at seven ancient sites in this region contain surgical holes in the same spot, in the middle of the back of the head, say archaeologist Julia Gresky of the German Archaeological Institute in Berlin and her colleagues. That’s a particularly dangerous location for this kind of skull surgery, also known as trepanation, the scientists report online April 21 in the American Journal of Physical Anthropology. It’s not an area of the skull typically targeted in ancient trepanations, which go back roughly 11,000 years in West Asia. “There may have been an original medical purpose for these trepanations, which over time changed to a symbolic treatment,” Gresky says.
Archaeologist Maria Mednikova of the Russian Academy of Sciences in Moscow agrees that skulls in Gresky’s new study probably represent cases of ritual trepanation. She previously examined some of the same skulls. Trepanation may have been used in some ancient cultures as part of a rite of passage for people taking on new social roles, Mednikova speculates.
Carving a center hole in the back of peoples’ heads was a potentially fatal procedure. Surgeons would have needed to know precisely how deep to scrape or grind bone to avoid penetrating a blood-drainage cavity for the brain. They also had to know how to stop potentially fatal bleeding of veins nicked during surgery. The procedure must have been performed as fast as possible to minimize bleeding, the researchers suspect.
Yet 11 of 13 skull openings show signs of healing and bone regrowth, indicating that these individuals survived the operation and often lived for years after. The researchers identify six males and six females in the skull sample. One specimen’s sex couldn’t be determined from skull features.
Most individuals died between ages 20 and 40. One female with a layer of bone that had regrown from the inside border of a trepanation hole died between ages 14 and 16, suggesting her skull surgery had occurred as young as age 10, the researchers estimate.
CT scans, X-rays and analyses of bone surfaces produced no evidence of injuries or brain tumors that could have motivated surgery. Ancient skull surgery intended as a medical treatment often involved holes on the side of the head, near fractures from some type of blow to the head (SN Online: 4/25/08). It’s impossible to determine from bones whether trepanations were aimed at treating chronic headaches, epilepsy, psychological problems or difficulties attributed to evil spirits.
Other evidence, in addition to the risky and unusual location of trepanation holes, points to ritual skull surgeries in southern Russia, Gresky says. Many of these individuals were interred according to special customs, suggesting they ranked high in their societies. For instance, the skulls of seven people buried in a pit at one site had been grouped together near bundled fragments of limb bones in a special display. Incisions on the limb bones indicate that bodies had been dismembered after death before being ritually buried. Of the seven skulls, five display surgical openings at the back of the head. Another contains scrapes from a partial trepanation. Partial trepanations were probably intentional rather than unfinished, with their own cultural significance, Mednikova says.
Trepanation holes on the sides of another six skulls found at the same southern Russian sites were probably made to treat medical conditions, Gresky says. Surgical openings on several of these skulls are located near bone fractures.
Rituals and meanings attached to ancient trepanations in southern Russia will remain mysterious, Mednikova predicts. “We don’t know the myths and religions of tribes that lived there 6,000 years ago.”
Physicists of all stripes seem to have one thing in common: They love smashing things together. This time-honored tradition has now been expanded from familiar particles like electrons, protons, and atomic nuclei to quasiparticles, which act like particles, but aren’t.
Quasiparticles are formed from groups of particles in a solid material that collectively behave like a unified particle (SN: 10/18/14, p. 22). The first quasiparticle collider, described May 11 in Nature, allows scientists to probe the faux-particles’ behavior. It’s a tool that could potentially lead researchers to improved materials for solar cells and electronics applications. “Colliding particles is really something that has taught us so much,” says physicist Peter Hommelhoff of the University of Erlangen-Nuremberg in Germany, who was not involved with the research. Colliding quasiparticles “is really interesting and it’s really new and pretty fantastic.”
It’s a challenge to control these fleeting faux-particles. “They are very short-lived and you cannot take them out of their natural habitat,” says physicist Rupert Huber of University of Regensburg in Germany, a coauthor of the study. But quasiparticles are a useful way for physicists to understand how large numbers of particles interact in a solid.
One quasiparticle, known as a hole, results from a missing electron that produces a void in a sea of electrons. The hole moves around the material, behaving like a positively charged particle. Its apparent movement is the result of many jostling electrons.
The new quasiparticle collider works by slamming holes into electrons. Using a short pulse of light, the researchers created pairs of electrons and holes in a material called tungsten diselenide. Then, using an infrared pulse of light to produce an oscillating electric field, the researchers ripped the electrons and holes apart and slammed them back together again at speeds of thousands of kilometers per second — all within about 10 millionths of a billionth of a second.
The smashup left its imprint in light emitted in the aftermath, which researchers analyzed to study the properties of the collision. For example, when holes get together with electrons, they can bind into an atomlike state known as an exciton. The researchers used their collider to estimate the excitons’ binding energy — a measure of the effort required to separate the pair. The collider could be useful for understanding how quasiparticles behave in materials — how they move, interact and collide. Such quasiparticle properties are particularly pertinent for materials used in solar cells, Huber says. When sunlight is absorbed in solar cells, it produces pairs of electrons and holes that must be separated and harvested to produce electricity.
The researchers also hope to study quasiparticles in other materials, like graphene, a sheet of carbon one atom thick (SN: 08/13/11, p. 26). Scientists hope to use graphene to create superthin, flexible electronics, among other applications. Graphene has a wealth of unusual properties, not least of which is that its electrons can be thought of as quasiparticles; unlike typical electrons, they behave like they are massless.
Obliterating bacteria in the gut may hurt the brain, too.
In mice, a long course of antibiotics that wiped out gut bacteria slowed the birth of new brain cells and impaired memory, scientists write May 19 in Cell Reports. The results reinforce evidence for a powerful connection between bacteria in the gut and the brain (SN: 4/2/16, p. 23).
After seven weeks of drinking water spiked with a cocktail of antibiotics, mice had fewer newborn nerve cells in a part of the hippocampus, a brain structure important for memory. The mice’s ability to remember previously seen objects also suffered. Further experiments revealed one way bacteria can influence brain cell growth and memory. Injections of immune cells called Ly6Chi monocytes boosted the number of new nerve cells. Themonocytes appear to carry messages from gut to brain, Susanne Wolf of the Max Delbrück Center for Molecular Medicine in Berlin and colleagues found.
Exercise and probiotic treatment with eight types of live bacteria also increased the number of newborn nerve cells and improved memory in mice treated with antibiotics. The results help clarify the toll of prolonged antibiotic treatment, and hint at ways to fight back, the authors write.
When molecular biologist Kate Rubins blasts off from Kazakhstan on June 24, strapped into the Soyuz spacecraft bound for the International Space Station, the trip will cap off seven years of preparing — and 30 years of hoping.
As a child, Rubins plastered her Napa, Calif., bedroom with pictures of the space shuttle, proudly announcing her intention to be an astronaut. A week at Space Camp in Huntsville, Ala., in seventh grade cemented her vision. But by high school, she concluded that astronaut wasn’t “a realistic job,” she says. Flash forward to 2009: Rubins is running a lab at the Whitehead Institute for Biomedical Research in Cambridge, Mass., focusing on virus-host interactions and viral genomics. A friend points out a NASA ad seeking astronaut candidates, and Rubins’ long-dormant obsession awakens. Since then, she has learned how to fly a T-38 jet, speak Russian to communicate with her cosmo-naut crewmates, conduct a spacewalk, operate the robotic arm on the ISS and even fix the habitable satellite’s toilet.
Joining NASA meant leaving her 14-person lab behind. But Rubins gained the rare opportunity to collaborate with dozens of scientists in fields as diverse as cell biology and astrophysics. On the space station, she’ll be “their hands, eyes and ears,” conducting about 100 experiments over five months.
She will, for instance, probe how heart cells behave when gravity doesn’t get in the way. And she’ll test a hand-held DNA sequencer, which reads out the genetic information stored in DNA and will be important to future missions looking for signatures of life on Mars.
At times, Rubins will be both experimenter and subject. In one study, she will observe bone cells in a lab dish, comparing their behavior with what happens in a simulated gravity-free environment on the ground. Because astronauts in space are vulnerable to rapid bone loss, CT scanning before and after the mission will also document changes in Rubins’ own hip bone.
Rubins is particularly eager to examine how liquid behaves in microgravity on a molecular scale. In 2013, Canadian astronaut Chris Hadfield created an Internet sensation when he demonstrated that wringing out a wet washcloth in space caused water to form a bubble that enveloped the cloth and his hands. “It’s incredibly bizarre,” Rubins says. Understanding how fluids move in test tubes in space will help NASA plan for Mars exploration, among other applications. Before any of the research can begin, Rubins has to get off the ground. As treacherous as accelerating to 17,500 miles per hour may sound, she’s not worried.
“An important part of the training experience is making all the information and skills routine,” she says. She predicts that sitting down in the Soyuz spacecraft, pulling out her procedures and getting ready to launch will feel a lot like going into the lab and picking up a pipette — “a normal day at the office.”
Until the engines turn on, anyway. “I think it’s going to feel different when there’s a rocket underneath.”
Hair, scales and feathers arose from one ancestral structure, a new study finds.
Studies in fetal Nile crocodiles, bearded dragon lizards and corn snakes appear to have settled a long-standing debate on the rise of skin coverings. Special skin bumps long known to direct the development of hair in mammals and feathers in birds also turn out to signal scale growth in reptiles, implying all three structures evolved from a shared ancestor, scientists report online June 24 in Science Advances. In embryonic birds and mammals, some areas of the skin thicken into raised bumps. Since birds evolved from ancient reptiles, scientists expected that modern snakes, lizards and crocodiles would have the same structures. A study at Yale University last year found that one protein already known to be important in hair and feather development is also active in the skin of developing alligators. But the team did not find the telltale skin thickening. Without that evidence from modern reptiles, scientists weren’t sure if the bumps had been lost in reptiles, or if birds and mammals had evolved them independently, using the same set of genes. The new results are “a relief,” says Michel Milinkovitch, whose lab led the new study at the University of Geneva. Scientists had come up with a variety of complicated ideas to explain how birds and mammals could share a structure that reptiles lack. But, he says, “the reality is much simpler.”
Clues from a mutant lizard inspired Milinkovitch’s team to probe the mystery. Nicolas Di-Poï, a coauthor of the new study who is now at the University of Helsinki, found that a hair-development gene called EDA was present, but disrupted, in scaleless, or “silky,” bearded dragons. Di-Poï and Milinkovitch searched for similar molecular signals in normal reptile embryos and found genes and proteins associated with hair and feather growth studding the skin. Cell staining revealed characteristic skin thickening at those signal centers.
Reptilian skin bumps eluded previous researchers because they are tiny, appear briefly and don’t all come in at once as they do in mammals, Milinkovitch speculates. “You have to look in the right place at the right time to see them,” he says. “Then boom, you see them, and you’re like, ‘Whoa, they are exactly the same.’”
This study “addresses a fundamental question about identity for skin structures,” says paleontologist Marcelo Sánchez of the University of Zurich, who was not involved in the new research. It’s especially important that the team used crocodiles, lizards and snakes, which are far from typical lab animals, he says. Using nonmodel organisms “gives new insight into evolution we wouldn’t get otherwise.”
The next step is to understand how hairs, feathers and scales diversified from the same ancestral structure. That primordial body covering wasn’t necessarily a scale, says evolutionary biologist Günter Wagner, an author of the 2015 Yale study. “Even though intuitively you would think reptilian-like skin is ancestral, compared to mammals,” he says “it’s entirely unclear what kind of structure the scales and feathers on the one side and hair on the other has evolved from.”
A gaping wound in Earth’s atmosphere is definitively healing. Since 2000, the average size of the Antarctic ozone hole in September has shrunk by about 4.5 million square kilometers, an area larger than India, researchers report online June 30 in Science. While the hole won’t close completely until at least midcentury, the researchers say the results are a testament to the success of the Montreal Protocol. That international treaty, implemented in 1989, banned ozone-depleting chemicals called chlorofluorocarbons worldwide.
Ozone helps shield life on Earth from hazardous ultraviolet radiation. Tracking the ozone layer’s recovery process is tricky because natural phenomena such as volcanic eruptions and weather variations can alter the size of the ozone hole. While some earlier studies suggested that the ozone had already begun healing (SN: 6/4/11, p. 15), many scientists questioned whether the work had been detailed enough to separate out the effects of natural variability.
MIT atmospheric scientist Susan Solomon and colleagues used a sophisticated 3-D atmospheric simulation to distinguish between the forces acting on atmospheric ozone. The work suggests that about half of the ozone hole’s recent shrinkage resulted from a drop in chlorofluorocarbons in the atmosphere; the remainder stemmed from weather changes.
Volcanic eruptions obscure healing signs. Last October, the ozone hole reached a record-setting average size of 25.3 million square kilometers — an area larger than Russia — thanks to the April 2015 eruption of Chile’s Calbuco volcano. That large size doesn’t disprove that the ozone hole is healing in the long run, though. Without the temporary 4.2-million-square-kilometer boost from the volcano, the hole’s average size would have peaked at a more modest 21.1 million square kilometers, the researchers estimate.
For a “three-parent baby,” getting disease-free mitochondrial DNA from a surrogate may do more than just avert disease: For better or for worse, a donor’s mitochondria could also affect the course of aging, new research shows.
Two strains of mice – genetically identical except for the source of their mitochondria, the energy centers of cells – aged very differently, researchers report online July 6 in Nature. Even though both mouse strains had healthy mitochondrial DNA, the mice with mitochondria that did not come from the same source as the rest of their DNA fared better later in life: After two years, these mice showed fewer signs of aging and had a lower incidence of tumors. The results don’t necessarily mean that a mitochondria transplant leads to a healthier life. This is just one case, researchers caution. Other DNA mixes and matches could turn out differently. But the study’s finding does point to a larger relationship between mitochondrial DNA and aging and raises new questions about the long-term effects of creating three-parent babies.
What the new results mean for people is still unclear, says Michio Hirano, a neurologist at Columbia University who was not involved in the study. But if the findings do apply to humans, he says, “you can blame your mother for how you age.”
Mitochondrial DNA is passed down from mother to child. Three-parent babies are created through an in-vitro fertilization technique that substitutes a mother’s diseased mitochondria for the healthy mitochondria of a surrogate (SN: 11/17/12, p. 5). In the procedure, which is legal in the United Kingdom and deemed ethical by a U.S. panel of experts this year (SN Online: 2/3/16), a baby inherits its nuclear DNA — the majority of its genetic fingerprint — from mom and dad. But a small amount of DNA — just 37 genes — comes from the mitochondria of a second, healthy woman.
Mitochondria do more than just power cells; they also play big roles in cell-to-cell communication and metabolism. Over the last two decades, mitochondria have also been implicated in aging but without conclusive evidence. The new research, Hirano says, “adds fuel to this debate.”
In the study, José Enríquez of the Spanish National Center for Cardiovascular Research in Madrid and colleagues bred two strains of mice. The original strain was called C57/Black 6. A second strain of C57/Black 6 carried mitochondria from another kind of mouse called NZB. This mismatch mimicked the effects of a mitochondrial transplant. Early in life, normal C57 mice bulked up faster than those carrying NZB mitochondria and had 11 percent longer telomeres (protective caps at the ends of chromosomes that get shorter over time, so are used as a proxy for aging). But later in life, the mice with NZB mitochondria had longer telomeres, less fat in their muscles and lower risk of having liver tumors at the end of their lives. Young C57 mice “tend to be stronger,” Enríquez says, probably because their mitochondrial and nuclear DNA are a good match and make efficient mitochondria. The weaker batteries in the mice with mismatched mitochondria may cause more cellular stress early on, he says, which may toughen up these mice to age more gracefully.
Since the study was done in mice, researchers don’t know how mitochondrial substitution would affect aging in humans. To avoid unforeseen and unwanted consequences, Enríquez urges caution. “Before we understand it better,” a mitochondrial transplant should mimic natural conditions, he says: “Why don’t we match the mitochondrial DNA of the donor and receptor?”
