Direct-to-consumer genetic testing first came on the market about a decade ago, but I resisted the temptation to see what health information is hidden in my DNA — until now.
As a molecular biology writer, I’ve been skeptical that the field of genetics is mature enough to accurately predict health (see related article). What finally motivated me to send away my DNA in the mail was the fact that companies are now offering much more genetic information. Is more better? Would an expensive test that deciphered my entire genetic instruction manual, or genome, reveal more about me than more limited tests? That’s what I wanted to find out.
For health testing, I sent spit samples to 23andMe, Genos and Veritas Genetics, three companies that represent the various levels of DNA testing available to consumers. (I did ancestry testing, too; you can read about my experiences with that in June.) These companies all analyze natural spelling variations in the string of letters that make up DNA. Where most people have, say, a “G,” some might have an “A.” Most of these genetic variants are harmless, but some raise the risk for certain diseases.
Where these companies differ is in how much of the genome they assess and whether they look for only a limited set of known variants or can uncover new ones specific to an individual. Getting started The DNA-testing process starts off the same for all of the companies I tried: ordering a kit online. Genos and Veritas both require a doctor to sign off on the test. 23andMe doesn’t, and as a result, the U.S. Food and Drug Administration limits the medical information the company can report. My doctor reluctantly agreed, but only because I was exploring DNA testing as part of my job. She said there was nothing in my personal health records or family history that would normally lead her to order a genetic test.
The kits all contained the same type of saliva-collection tubes. Sample prep was easy — register the kit’s number online, spit in a tube, mail in the sample. I also opted to let each company use my DNA in research studies, which required an extra step of answering a questionnaire about myself.
Within a couple of months, 23andMe and Genos emailed to tell me my results were available online. Because of a technical glitch, it took about seven months to get results from Veritas. The company says the typical wait time is closer to 12 weeks. Veritas also sent a copy of its report to my doctor.
23andMe 23andMe uses the oldest technology, called SNP genotype testing. SNPs, short for single nucleotide polymorphisms, are the spelling variations in DNA. For $199, 23andMe examines about 690,000 predetermined SNPs. That may sound like a lot, but it’s only 0.01 percent of the 6 billion DNA letters in the human genome. It’s the genetic equivalent of spot-checking a few letters in each chapter of War and Peace and trying to decipher the plot. Still, the company can tell you interesting things about some physical and physiological traits, like cleft chins, dimples or the ability to taste bitter flavors. And 23andMe has FDA approval to report on a few health conditions linked to specific genetic variants, such as celiac disease and macular degeneration.
The problem is, the company tests only a small subset of all potential SNPs. Getting a report of “variants not detected” doesn’t mean you don’t have any variants related to a particular medical condition. It just means you don’t have the ones tested for.
On the plus side, 23andMe provides clear explanations of what it does and doesn’t test for, and lists other factors that contribute to disease risk. In fact, 23andMe does a far better job than Genos or Veritas of explaining what having specific genetic variants means.
Genos Genos offers broader testing, for $499. It reads, or “sequences,” every letter in a person’s protein-producing genes. By deciphering this Cliffs Notes version of the genome, called the exome, Genos can theoretically find genetic changes that are unique to an individual, though the significance of these finds for health isn’t always clear. Compared with the other two services, Genos gave me the most data but the least useful information. The company found 44,225 variants in my exome and showed me how many are on each chromosome. But Genos provided information for just 4,294 of them because those variants are in ClinVar, the publicly available database that Genos draws information from.
And even for these variants, Genos gave few details — like how common the variants are and whether they change one of my proteins. The company offered almost no interpretation of what the variants mean for my health, other than to classify how harmful they might be: pathogenic, likely pathogenic, likely benign, benign or unknown significance. Most frustrating, Genos didn’t tell me which diseases these variants are associated with. I would need to explore the scientific literature myself to figure this out. So for most people, Genos’ report wouldn’t be that useful.
The company did, however, have more to say about how my variants influence a variety of my traits, such as hair and eye color, freckling, several characteristics of my ears and my ability to smell cut grass, roses and sweat. Genos also reports how genetics can affect a few behavioral characteristics, such as a tendency to overeat and the propensity to worry.
Veritas Genetics Finally, Veritas charged $999 to read nearly every letter in my genome, including portions in between genes that regulate gene activity and parts containing noncoding RNAs, which do a variety of cellular jobs. Those sections between genes are proving to be lush territory for discovering health risks. Not surprisingly, Veritas gave me the most wide-ranging report. For instance, only Veritas shared “pharmacogenomic” information — how my genetic variants could influence how certain drugs affect me. The list of drugs my genes may or may not play well with is long. I take only one drug on the list, but I’m glad to have all of this information in case it becomes relevant in the future.
While Veritas has nearly the entirety of my genetic information in its data banks, the company told me surprisingly little. Turns out, I’m just not that interesting, genetically speaking. The company screened more than 40,000 genes (including the noncoding RNAs) but found no big health risks — at least, none that scientists can reliably predict today.
The company did cover a more extensive list of physical and physiological traits than either Genos or 23andMe did. Veritas’ focus is on medically relevant information, though, so the traits tended to be practical: for instance, how prone someone might be to tendon injuries, how muscles would respond to exercise, and how one’s genes might affect blood sugar and cholesterol levels.
Final assessment One thing I discovered from all this testing is that the companies don’t necessarily tell you everything they find in your DNA. Veritas, for instance, sometimes doesn’t report certain information that it doesn’t consider medically relevant. But that decision could have medical consequences.
I learned from 23andMe, for example, that I carry a variant linked to hemochromatosis, a disorder in which excess iron in the blood can build up and damage organs. My variant is unlikely to cause me harm, but it could be a problem for any future children if they also inherited a different harmful variant of the gene from their father. So that’s useful information to have if planning a family. (And indeed, my husband carries this variant, though the odds of us having a child with this disorder are still low.) My Veritas report did not mention the variant. When I checked with the company, Veritas said it chose not to report this variant because of its low likelihood of causing me trouble. But I would prefer to have that information.
Overall, none of these genetic testing companies give you complete information about your health and genetics. Veritas may give you the most bang for your health care dollar, but its report is definitely not as user-friendly as 23andMe’s. Unless you’re a hard-core genetics nerd like me, Genos in its current form could be a frustrating experience.
Before you decide to get your DNA tested for medical reasons, talk to a genetic counselor to see which level of sequencing best suits your needs. If testing uncovers something worrisome, the result should be confirmed by a doctor. Keep in mind that genetics is an inexact science. Someday it will be better. If you can wait for that day, you may have a more satisfying experience. If you just can’t wait, take the results with a grain of salt and keep an open mind. As scientists learn more, interpretations may change.
In 1918, a pandemic of Spanish flu killed as much as 5 percent of the world’s population. A hundred years later, scientists know much more about how to prevent and treat such diseases. But in some ways, the threat of a global outbreak is greater than ever. All it takes is one plane ride for a few localized cases of a disease to become an epidemic.
A new exhibit at the Smithsonian National Museum of Natural History in Washington, D.C., traces the way infectious diseases still shape our world. The exhibit, called “Outbreak: Epidemics in a Connected World,” is centered around the concept of One Health — the idea that the health of humans, other animals and the environment are all intertwined, so protecting one requires protecting all (SN: 3/31/18, p. 20). News coverage of disease outbreaks often focuses on the deaths they cause, notes Jonathan Epstein of EcoHealth Alliance, the exhibit’s chief science adviser. One goal of the exhibit, he says, is “to give the public a look at how these things get started.” With that in mind, “Outbreak” highlights a handful of epidemics that have occurred in the last century, using each as a jumping off point to explore different aspects of preventing, tracing, treating and containing infectious diseases. In addition to zeroing in on epidemics that have made international headlines, including Ebola and SARS, the exhibit features lesser-known diseases. Nipah virus, for instance, has infected people in Bangladesh who have drunk sweet date palm sap contaminated by infected bats. Simple preventive measures like encouraging people not to drink the raw sap or to filter it, so far, have prevented the virus from sparking an epidemic.
“Outbreak” is more focused on text and interactive screens than on artifacts, which makes sense given the microscopic subjects. But the exhibit does draw on the Smithsonian’s extensive collections, showcasing arrays of preserved infectious disease vectors, such as ticks and mosquitoes, as well as bat and macaque specimens. As these display cases explain, monitoring the health of animal populations helps researchers put preventive measures in place before emerging infectious diseases can jump to humans. As an entry point for discussing the social side of disease and the stigma that infected people can face, a collection of buttons and signs from AIDS activists recalls the fight for public recognition and government action in the 1980s and ’90s. The content on display might not be a good fit for very young children, but interactive games and activities throughout increase the exhibit’s overall kid appeal. In one game, played on touch screens, players each pick from a variety of roles — such as epidemiologist, wildlife biologist or community worker — and then cooperate to complete tasks that stem the tide of a fictional outbreak. (It’s a good example of the broader message that stopping infectious diseases requires collaboration from many different kinds of experts.)
In case Washington isn’t on your travel agenda, the Smithsonian is translating the content into multiple languages and sharing it with libraries, community centers and other institutions around the world to help them create their own pared-down versions of the exhibit.
If you’re looking for starry skies, exotic plant life and extreme weather on your summer vacation, NASA’s Exoplanet Travel Bureau has just the spot. Consider a trip to Kepler 186f.
This extrasolar planet is nearly 558 light-years away, so a real trip may be out of your budget — and astronomers aren’t sure if the sphere even has a life-sustaining atmosphere. But NASA’s Exoplanet Exploration website offers a virtual tour of what visiting the alien world might be like. No one has taken a real photo of the surface of any exoplanet (yet). But artists have generated possible landscapes based on what astronomers know, including the planets’ sizes, masses and temperatures, as well as the sizes and temperatures of their stars.
For instance, Kepler 186f, discovered in 2014, orbits at a distance from its small dim star that would allow temperatures to sustain liquid water at the surface, if the planet has an atmosphere. The interactive website lets you scroll around the landscape (with and without an atmosphere) and view “hypothetical” water, plant life and clouds. Don’t forget to look up.
If that’s not your idea of paradise, you (and your shadows) could check out Kepler 16b or do a little planet-gazing from TRAPPIST-1d, which has six sibling worlds in such close orbits that the orbs would all be visible in the sky.
On a warm summer evening, a visitor to 1920s Göttingen, Germany, might have heard the hubbub of a party from an apartment on Friedländer Way. A glimpse through the window would reveal a gathering of scholars. The wine would be flowing and the air buzzing with conversations centered on mathematical problems of the day. The eavesdropper might eventually pick up a woman’s laugh cutting through the din: the hostess, Emmy Noether, a creative genius of mathematics.
At a time when women were considered intellectually inferior to men, Noether (pronounced NUR-ter) won the admiration of her male colleagues. She resolved a nagging puzzle in Albert Einstein’s newfound theory of gravity, the general theory of relativity. And in the process, she proved a revolutionary mathematical theorem that changed the way physicists study the universe.
It’s been a century since the July 23, 1918, unveiling of Noether’s famous theorem. Yet its importance persists today. “That theorem has been a guiding star to 20th and 21st century physics,” says theoretical physicist Frank Wilczek of MIT.
Noether was a leading mathematician of her day. In addition to her theorem, now simply called “Noether’s theorem,” she kick-started an entire discipline of mathematics called abstract algebra. But in her career, Noether couldn’t catch a break. She labored unpaid for years after earning her Ph.D. Although she started working at the University of Göttingen in 1915, she was at first permitted to lecture only as an “assistant” under a male colleague’s name. She didn’t receive a salary until 1923. Ten years later, Noether was forced out of the job by the Nazi-led government: She was Jewish and was suspected of holding leftist political beliefs. Noether’s joyful mathematical soirees were extinguished.
She left for the United States to work at Bryn Mawr College in Pennsylvania. Less than two years later, she died of complications from surgery — before the importance of her theorem was fully recognized. She was 53. Although most people have never heard of Noether, physicists sing her theorem’s praises. The theorem is “pervasive in everything we do,” says theoretical physicist Ruth Gregory of Durham University in England. Gregory, who has lectured on the importance of Noether’s work, studies gravity, a field in which Noether’s legacy looms large.
Making connections Noether divined a link between two important concepts in physics: conservation laws and symmetries. A conservation law — conservation of energy, for example — states that a particular quantity must remain constant. No matter how hard we try, energy can’t be created or destroyed. The certainty of energy conservation helps physicists solve many problems, from calculating the speed of a ball rolling down a hill to understanding the processes of nuclear fusion.
Symmetries describe changes that can be made without altering how an object looks or acts. A sphere is perfectly symmetric: Rotate it any direction and it appears the same. Likewise, symmetries pervade the laws of physics: Equations don’t change in different places in time or space. Noether’s theorem proclaims that every such symmetry has an associated conservation law, and vice versa — for every conservation law, there’s an associated symmetry.
Conservation of energy is tied to the fact that physics is the same today as it was yesterday. Likewise, conservation of momentum, the theorem says, is associated with the fact that physics is the same here as it is anywhere else in the universe. These connections reveal a rhyme and reason behind properties of the universe that seemed arbitrary before that relationship was known. During the second half of the 20th century, Noether’s theorem became a foundation of the standard model of particle physics, which describes nature on tiny scales and predicted the existence of the Higgs boson, a particle discovered to much fanfare in 2012 (SN: 7/28/12, p. 5). Today, physicists are still formulating new theories that rely on Noether’s work.
When Noether died, Einstein wrote in the New York Times: “Noether was the most significant creative mathematical genius thus far produced since the higher education of women began.” It’s a hearty compliment. But Einstein’s praise alluded to Noether’s gender instead of recognizing that she also stood out among her male colleagues. Likewise, several mathematicians who eulogized her remarked on her “heavy build,” and one even commented on her sex life. Even those who admired Noether judged her by different standards than they judged men.
Symmetry leads the way There’s something inherently appealing about symmetry (SN Online: 4/12/07). Some studies report that humans find symmetrical faces more beautiful than asymmetrical ones. The two halves of a face are nearly mirror images of each other, a property known as reflection symmetry. Art often exhibits symmetry, especially mosaics, textiles and stained-glass windows. Nature does, too: A typical snowflake, when rotated by 60 degrees, looks the same. Similar rotational symmetries appear in flowers, spider webs and sea urchins, to name a few. But Noether’s theorem doesn’t directly apply to these familiar examples. That’s because the symmetries we see and admire around us are discrete; they hold only for certain values, for example, rotation by exactly 60 degrees for a snowflake. The symmetries relevant for Noether’s theorem, on the other hand, are continuous: They hold no matter how far you move in space or time.
One kind of continuous symmetry, known as translation symmetry, means that the laws of physics remain the same as we move about the cosmos.
The conservation laws that relate to each continuous symmetry are basic tools of physics. In physics classes, students are taught that energy is always conserved. When a billiard ball thwacks another, the energy of that first ball’s motion is divvied up. Some goes into the second ball’s motion, some generates sound or heat, and some energy remains with the first ball. But the total amount of energy remains the same — no matter what. Same goes for momentum.
These rules are taught as rote facts, but there’s a mathematical reason behind their existence. Energy conservation, according to Noether, comes from translation symmetry in time. Similarly, momentum conservation is due to translation symmetry in space. And conservation of angular momentum, the property that allows ice skaters to speed up their spins by hugging their arms close to their bodies, emerges from rotational symmetry, the idea that physics stays the same as we spin around in space.
In Einstein’s general theory of relativity, there is no absolute sense of time or space, and conservation laws become more difficult to comprehend. It’s that complexity that brought Noether to the topic in the first place.
Gravity gets Noether’d In 1915, general relativity was a fascinating new theory. German mathematicians David Hilbert and Felix Klein, both at the University of Göttingen, were immersed in the new theory’s quirks. Hilbert had been competing with Einstein to develop the mathematically complex theory, which describes gravity as the result of matter curving spacetime (SN: 10/17/15, p. 16).
But Hilbert and Klein stumbled on a puzzle. Attempts to use the framework of general relativity to write an equation for conservation of energy resulted in a tautology: Like writing “0 equals 0,” the equation had no physical significance. This situation was a surprise to the pair; no previously accepted theories had energy conservation laws like this. The duo wanted to understand why general relativity had this peculiar feature.
The two recruited Noether, who had expertise in relevant areas of mathematics, to join them in Göttingen and help them solve the riddle.
Noether showed that the seemingly strange type of conservation law was inherent to a certain class of theories known as “generally covariant.” In such theories, the equations associated with the theory hold whether you’re moving steadily or accelerating wildly, because both sides of the theory’s equations change in sync. The result is that generally covariant theories — including general relativity — will always have these nontraditional conservation laws. This discovery is known as Noether’s second theorem.
This is what Noether did best: fitting specific concepts into their broader mathematical context. “She was just able to see what’s right at the heart of what’s going on and to generalize it,” says philosopher of science Katherine Brading of Duke University, who has studied Noether’s theorems.
On her way to proving the second theorem, Noether proved her first theorem, about the connection between symmetries and conservation laws. She presented both results in a July 23, 1918, lecture to the Göttingen Mathematical Society, and in a paper published in Göttinger Nachrichten.
It’s not easy to find quotes of Noether reflecting on the significance of her work. Once she made a discovery, she seemed to move on to the next thing. She referred to her own Ph.D. thesis as “crap,” or “Mist” in her native German. But Noether recognized that she changed mathematics: “My methods are really methods of working and thinking; this is why they have crept in everywhere anonymously,” she wrote to a colleague in 1931.
“Warm like a loaf of bread” Born in 1882, Noether (her full name was Amalie Emmy Noether) was the daughter of mathematician Max Noether and Ida Amalia Noether. Growing up with three brothers in Erlangen, Germany, young Emmy’s mathematical talent was not obvious. However, she was known to solve puzzles that stumped other children.
At the University of Erlangen, where her father taught, women weren’t officially allowed as students, though they could audit classes with the permission of the professor. When the rule changed in 1904, Emmy Noether was quick to take advantage. She enrolled and earned her Ph.D. in 1907. As a woman, Noether struggled to find a paid academic position, even after being recruited to the University of Göttingen. Her supporters there argued that her sex was irrelevant. “After all, we are a university and not a bathing establishment,” Hilbert reportedly quipped. But that wasn’t enough to get her a salary.
Although Göttingen finally began paying Noether in 1923, she never became a full-fledged professor. Hermann Weyl, a prominent mathematician at the university, said, “I was ashamed to occupy such a preferred position beside her whom I knew to be my superior as a mathematician in many respects.”
Noether took these knocks in stride. She was beloved for her buoyant personality. Weyl described her demeanor as “warm like a loaf of bread.”
She made a habit of taking long walks in the countryside with her students and colleagues, holding lengthy, math-fueled debates. When legs began to ache, Noether and company would plop down in a meadow and continue chatting. Sometimes she’d take students to her apartment for homemade “pudding à la Noether,” conversing until remnants of the dessert had dried on the dishes, according to a 1970 biography, Emmy Noether 1882–1935, by mathematical historian Auguste Dick.
When she landed at Bryn Mawr, Noether continued her research and taught classes of women — a change of pace from her previous students, who were known as “the Noether boys.” She also lectured at the Institute for Advanced Study in Princeton, N.J. Her death, less than two years after her 1935 arrival, left the academic community grieving.
Russian mathematician Pavel Aleksandrov called Noether “one of the most captivating human beings I have ever known,” and lamented the unfortunate circumstances of her employment. “Emmy Noether’s career was full of paradoxes, and will always stand as an example of shocking stagnancy and inability to overcome prejudice,” he said in 1935 at a meeting of the Moscow Mathematical Society.
Elusive partners But Noether’s theorems remained relevant, particularly within particle physics. In the minute, enigmatic world of fundamental particles, teasing out what’s going on is difficult. “We have to rely on theoretical insight and concepts of beauty and aesthetics and symmetry to make guesses about how things might work,” Wilczek says. Noether’s theorems are a big help.
In particle physics, the relevant symmetries are hidden kinds known as gauge symmetries. One such symmetry is found in electromagnetism and results in the conservation of electric charge.
Gauge symmetry appears in the definition of electric voltage. A voltage — between two ends of a battery, for example — is the result of a difference in electric potential. The actual value of the electric potential itself doesn’t matter, only the difference.
This creates a symmetry in electric potential: Its overall value can be changed without affecting the voltage. This property explains why a bird can sit on a single power line without getting electrocuted, but if it simultaneously touches two wires at different electric potentials — bye-bye, birdie.
In the 1960s and ’70s, physicists extended this idea, finding other hidden symmetries associated with conservation laws to develop the standard model of particle physics.
“There’s this conceptual link that — once you realize it — you have a hammer and you go in search of nails to use it on,” Wilczek says. Anywhere they found a conservation law, physicists looked for a symmetry, and vice versa. The standard model, which Wilczek shared a 2004 Nobel Prize for his role in developing, explains a plethora of particles and their interactions. It is now considered by many physicists to be one of the most successful scientific theories ever, in terms of its ability to precisely predict the results of experiments. At the Large Hadron Collider, at CERN in Geneva, physicists are still searching for new particles predicted using Noether’s insights. A hypothetical hidden symmetry, dubbed supersymmetry because it proposes another level of symmetry in particle physics, posits that each known particle has an elusive heavier partner.
So far, no such particles have been found, despite high hopes for their detection (SN: 10/1/16, p. 12). Some physicists are beginning to ask if supersymmetry is correct. Perhaps symmetry can only take physicists so far.
That notion is leaving some physicists in a bit of a lurch: “If that’s not going to be your guiding motto all the time — that more symmetry is better — then what will be your guiding motto?” asks mathematical physicist John Baez of the University of California, Riverside.
Holograms get symmetric Despite such disappointments, symmetry maintains its luster in physics at large. Noether’s theorems are essential tools for developing potential theories of quantum gravity, which would unite two disparate theories: general relativity and quantum mechanics. Noether’s work helps scientists understand what kinds of symmetries can appear in such a unified theory.
One candidate relies on a proposed connection between two types of complementary theories: A quantum theory of particles on a two-dimensional surface without gravity can act as a hologram for a three-dimensional theory of quantum gravity in curved spacetime. That means the information contained in the 3-D universe can be imprinted on a surrounding 2-D surface (SN: 10/17/15, p. 28).
Picture a soda can with a label that describes the size and location of each bubble inside. The label catalogs how those bubbles merge and pop. A curious researcher could use the behavior of the can’s surface to understand goings-on inside the can, for example, calculating what might happen upon shaking it. For physicists, understanding a simpler, 2-D theory can help them comprehend a more complicated mess — namely, quantum gravity — going on inside. (The theory of quantum gravity for which this holographic principle holds is string theory, in which particles are described by wiggling strings.) “Noether’s theorem is a very important part of that story,” says theoretical physicist Daniel Harlow of MIT. Symmetries in the 2-D quantum theory show up in the 3-D quantum gravity theory in a different context. In a satisfying twist, Noether’s first and second theorems become linked: Noether’s first theorem in the 2-D picture makes the same statement as Noether’s second theorem in 3-D. It’s like taking two sentences, one in Japanese and one in English, and realizing upon translating them that both say the same thing in different ways.
New directions for Noether Everyday physics relies on Noether’s theorem as well. The conservation laws it implies help to explain waves on the surface of the ocean and air flowing over an airplane wing.
Simulating such systems helps scientists make predictions — about weather patterns, vibrations of bridges or the effects of a nuclear blast, for example. Noether’s theorem doesn’t automatically apply in computer simulations, which simplify the world by slicing it up into small chunks of space and time. So programmers have to manually add in conservation laws for energy and momentum.
“They throw away all of the physics, and then they have to try and force it all back in somehow,” says mathematician Elizabeth Mansfield of the University of Kent in England. But Mansfield has found new ways to make Noether’s theorem apply in simulations. She and colleagues have simulated a person beating a drum inside a simplified Stonehenge, determining how sound waves would wrap around the stone — while automatically conserving energy. Mansfield says her method, which she will present in September in London at a Noether celebration, could eventually be used to create simulations that behave more like the real world.
In addition to Noether’s importance in physics, in mathematics her ideas are so prominent that her name has become an adjective. References to Noetherian rings, Noetherian groups and Noetherian modules are sprinkled throughout current mathematical literature.
Noether’s work “should have been a wake-up call to society that women could do mathematics,” Gregory says. Eventually, society did awaken. In a 2015 lecture she gave about Noether at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, Gregory showed a slide of herself with five female colleagues, then at the center for particle theory at Durham University. While women in science still face challenges, no one in the group had to struggle to get paid for her work. “That is Noether’s legacy, and I honestly think she would have been really jazzed,” Gregory says. “I think this would have been her real … vindication.”
A heavy element’s nucleus is all bent out of shape.
Nobelium — element number 102 on the periodic table — has an atomic nucleus that is deformed into the shape of an American football, scientists report in the June 8 Physical Review Letters. The element is the heaviest yet to have its nucleus sized up.
By probing individual nobelium atoms with a laser, the team gauged the oblong shape of three nobelium isotopes: nobelium-252, -253 and -254. These different forms of the element each contain 102 protons, but varying numbers of neutrons. The shape is not uncommon for nuclei, but the researchers also determined that nobelium-252 and -254 contain fewer protons in the center of the nucleus than the outer regions — a weird configuration known as a “bubble nucleus” (SN: 11/26/16, p. 11). The measurements are in agreement with previous theoretical predictions. “It nicely confirms what we believe,” says study coauthor Witold Nazarewicz, a theoretical nuclear physicist at Michigan State University in East Lansing.
Elements heavier than uranium, number 92, aren’t found in significant quantities in nature, and must be created artificially. Currently, the heaviest element on the periodic table is number 118, oganesson (SN Online: 2/12/18). But scientists hope to go even bigger, in search of a potential “island of stability,” a proposed realm in which elements are more stable than other heavy elements.
While many superheavy elements decay in just fractions of a second, some theoretical calculations suggest that elements inhabiting this proposed hinterland might persist longer, making them easier to study. Better understanding the heaviest known elements, including the shape of their atomic nuclei, could help scientists gauge what lies just out of reach.
New tech is revealing how young stars have an outsized influence on their environment. In this image from the Very Large Telescope in Chile, hundreds of newborn stars sculpt and illuminate gas and dust in their stellar nursery.
Released July 11 by the European Southern Observatory, the image shows star cluster RCW 38, which is located about 5,500 light-years from Earth toward the constellation Vela, in infrared light. Bright young stars shine in blue, while streams of cooler dust glow in darker red and orange. The stars are so bright and hot that their radiation pushes the dust and gas around them into intricate lacelike webs. Previous pictures of this cluster taken in visible light were far less detailed, as the dust and gas blocked the stars’ light. But longer-wavelength infrared light can shine through the fog.
This image was taken while astronomers were testing a new observation system on the Chilean telescope, including an infrared imager called HAWK-I and a method to reduce blurriness called GRAAL. GRAAL projects four lasers onto the sky to act as artificial stars (SN: 6/14/03, p. 373), letting astronomers focus on a “star” of known brightness and subtract the fuzziness of Earth’s atmosphere. That adjustment lets astronomers bring the real star cluster into sharper focus.
When invasive rats chow down on island seabirds, coral reefs suffer.
Researchers studied islands with and without the rodents in the Chagos Archipelago in the Indian Ocean. On rat-free isles, there were on average 1,243 birds per hectare compared with about two birds per hectare on rat-infested islands, the team found. And these rodentless islands had healthier coral reef ecosystems. The secret: Bird poop, naturally rich in nitrogen, washes into the ocean and helps keep reefs productive, the scientists report in the July 12 Nature. “We’re essentially linking three ecosystems in this study,” says study coauthor Nick Graham, an ecologist at Lancaster University in England. The rats affect the seabirds, which affect the reefs.
Introduced by humans to the Chagos Archipelago in the late 18th century, rats have since devastated native seabird populations, including red-footed boobies and terns. The rodents will eat seabird eggs, chicks and even the brains of adult birds, says Holly Jones, a restoration ecologist at Northern Illinois University in DeKalb who was not involved in the study. Rats are a major problem, Jones says, because seabirds are “ecosystem engineers.” When they’re gone, the environment on land and in the water changes dramatically. Bird poop, or guano, is rich in certain heavy nitrogen isotopes — different forms of the element with the same amount of protons but varying numbers of neutrons — which come from the animals’ diet. Graham and his colleagues tested for these isotopes on 12 islands, six with rat infestations and six that had no rats, and in nearby coral reefs. Compared with rat-infested islands, the team found much more of the heavy nitrogen in the soil of rat-free islands, where bird populations still thrived, and in the algae, sponges and fish in reefs that surrounded those islands. Bird guano is known to leach into the sea in rainwater or lapping waves, but its effects on reefs has been unclear. The researchers now suspect the reefs around rat-free islands are healthier in part because nitrogen can act as a fertilizer for ocean plants and algae. More algae grow, leading to more fish grazing on the reefs and helping clear out dead corals, essential processes for a healthy reef. The fish that lived near reefs with more nitrogen also grew larger and faster, the scientists showed.
In addition to these indirect effects on reefs, nitrogen may also directly help the corals, says David Gillikin, a biogeochemist at Union College in Schenectady, N.Y., who was not involved in the study. Between 15 and 50 percent of nitrogen found in corals comes directly from seabird guano, he says. Eradicating invasive rats from the islands will help preserve reefs, Graham says. Rat extermination has been done on 580 islands worldwide, with a success rate of about 85 percent.
Still, many coral reefs have been in trouble for decades and face various threats, including bleaching and ocean acidification, both consequences of climate change (SN: 5/12/18, p. 20). The UNESCO’s World Heritage Centre estimates that large coral reefs could be gone by the end of this century. “We’re constantly looking for solutions for the coral reef crisis,” Graham says.
Protecting seabirds to save coral reefs is one solution that doesn’t stink.
Painkillers crafted with a part of the wrinkle-smoothing drug Botox provide long-term pain relief in mice.
Researchers added the modified Botox to molecules that target pain-messaging nerve cells. Mice given a single spinal injection of the new drugs showed signs of pain relief for the full duration of the experiments, around three weeks, researchers report online July 18 in Science Translational Medicine. Such painkillers could potentially one day be developed for humans as alternatives to more addictive drugs, such as opioids. Created by the bacterium Clostridium botulinum, botulinum toxin causes the food poisoning disease botulism. Botox, which is made from the toxin, is often injected into people to iron out worry lines and has been used to treat conditions that involve overactive muscles, such as repetitive neck spasms or overactive bladder (SN: 4/5/08, p. 213). The toxin has also been used to reduce the frequency of migraines.
Biochemist Bazbek Davletov of the University of Sheffield in England and colleagues focused on botulinum toxin because it can stop certain nerve cells from communicating with one another for up to five months with each injection. And “you locally inject less than a millionth of a gram, which is helpful to avoid any immune response,” he says.
Davletov and colleagues created their new drugs with a process he describes as a “molecular Lego system.” Taking the part of the botulinum toxin that blocks nerve cells from sending messages, the team attached the piece to one of two molecules that target neurons that relay pain information. The researchers removed the part of the toxin, found in Botox, that binds to muscle-controlling nerve cells.
In the new study, the scientists injected SP-BOT, a botulinum toxin-based pain reliever they’d made previously, into the spinal fluid of male mice with pain due to nerve damage. SP-BOT provided pain relief starting around three days after the injection and lasted through the rest of the experiment. In another experiment, SP-BOT also mollified pain from inflammation due to a different injury. The researchers also created a new formula, called DERM-BOT, which targets nerve cell opioid receptors with dermorphin, a natural opioid secreted from the skin of a South American tree frog. DERM-BOT injected in mice with nerve damage kicked in right away and then provided pain relief to the rodents for over three weeks. The drug was also likewise effective in lessening pain from injuries that produced inflammation.
The team gauged the painkillers’ effectiveness by poking the animals’ paws with plastic filaments of different diameters. Mice in pain withdrew their paws from the finer filaments, Davletov says, while mice with pain relief didn’t withdraw until prodded by the thicker filaments, the same behavior seen in healthy mice.
Injecting the drugs into healthy mice caused no mobility issues, the researchers found, indicating that the drugs did not target muscle-controlling nerve cells as Botox does.
Neuroscientist Luana Colloca of the University of Maryland, Baltimore, who was not part of the study, says the drugs are promising candidates for further research in humans. Short-term painkillers, including morphine, may require multiple daily doses, and a body can build up tolerance and require higher doses for relief, she says. “One single administration lasting for several months can reduce the risk of dependence and addiction.”
But the drugs should be tested in female animals, Colloca adds. “We truly need to know if this data apply also to women in pain.”
An intergalactic race between light and a bizarre subatomic particle called a neutrino has ended in a draw.
The tie suggests that high-energy neutrinos, which are so lightweight they behave as if they’re massless, adhere to a basic rule of physics: Massless particles travel at the speed of light.
Comparing the arrival times of a neutrino and an associated blaze of high-energy light emitted from a bright, flaring galaxy (SN Online: 7/12/18) showed that the neutrino and light differed in speed by less than a billionth of a percent, physicists report in a paper posted July 13 at arXiv.org. Massless particles — including the particles of light known as photons — consistently move about 300,000 kilometers per second, while massive particles move more slowly. Although neutrinos have mass, their heft is so infinitesimal that high-energy neutrinos travel at a rate effectively indistinguishable from that of light.
Some theories propose that a “spacetime foam” might slow particles of very high energies. The idea is that spacetime on extremely small scales is not smooth, but foamy. As a result, high-energy particles could get bogged down, as if moving through molasses. That effect could cause a significant difference between the speeds of the neutrino and the associated light, which would build up into a delay over the 4-billion-light-year trip from the neutrino’s home galaxy to Earth. But since the flare of light was spotted around the same time as the neutrino, there’s no evidence for such a discrepancy.
The result once again refutes a 2011 claim that neutrinos might travel faster than light. That measurement, made by a particle detector known as OPERA, was eventually determined to have been distorted by a loose cable (SN: 4/7/12, p. 9).
In the final frenzy of reproduction and death, social amoebas secrete proteins that help preserve a starter kit of food for its offspring.
Dictyostelium discoideum, a type of slime mold in soil, eats bacteria. Some wild forms of this species essentially farm the microbes, passing them along in spore cases that give the next generation of amoebas the beginnings of a fine local patch of prey. Tests find that the trick to keeping the parental immune system from killing this starter crop of bacteria is a surge of proteins called lectins, researchers say in the July 27 Science. Lectins create a different way for the amoebas to treat bacteria: as actual symbionts inside cells, instead of as prey or infections, says study coauthor Adam Kuspa, a molecular cell biologist at Baylor College of Medicine in Houston. In a lab test of this ability, coating other bacteria with lectin derived from a plant allowed bacteria to slip inside cells from mice and survive as symbiotic residents.
The findings mark another chapter in a story that has been upending decades of what people thought they knew about social amoebas eating bacteria. The basic, almost alien, scenario is still true: D. discoideum amoebas, nicknamed Dicty, start life as single cells. When food dwindles, cells come together into a much bigger, multicellular slug-shaped creature with eight to 10 types of cells and the power to crawl. It then develops into something more like a fungus with a stalk holding up a case of spores, which start the next generation of amoebas. Those casings, scientists once believed, held only spores. “For 70 years, we all thought that Dictyostelium development was sterile,” meaning no bacteria survived among spores, Kuspa says. “If you were not a very good microbiologist and contaminated your amoeba sample, one way to cure them of bacteria was to put them through a cycle of development.” Then in 2011, researchers discovered that some Dicty strains are “farmers,” routinely packing live bacteria into spore cases, and jump-starting new bacterial livestock with each generation (SN: 2/12/11, p. 11). “That was a shock,” Kuspa says.
Researchers also discovered that the Dicty animal-like slug phase forms an immune system that kills bacteria, even as evidence grew that some bacteria had uses beyond food, such as providing defense chemistry. But how the slug avoided killing its own helpful bacteria was a mystery.
Comparing secretions of Dicty strains carrying bacteria versus strains that don’t showed a “dead-obvious” difference, Kuspa says: more lectins called discoidin A and discoidin C in the carrier forms. A series of tests supplying and withholding the proteins showed big effects on the fates of bacteria. The researchers found that the lectins raise the chances that bacteria can slip inside an amoeba cell and live hidden from immune-system sentinels that purge free-living intruders. That gives the bacteria a chance to end up in the spore case.
Lectins’ powers help make sense of how the startling discovery of bacterial farming fits with the revelation of social amoebas’ bacteria-killing immune systems. “Outstanding” work, says Debra Brock of Washington University in St. Louis, who studies both phenomena. “I love mechanisms.”
