Hornbills join toucans in the cool beak club

In the scorching heat of the Kalahari Desert, some birds still manage to keep their cool.

Thermal imaging reveals that the southern yellow-billed hornbill (Tockus leucomelas) vents heat from its beak, a phenomenon previously observed in toco toucans (Ramphastos toco). A team of South African researchers snapped infrared photos of 18 hornbills on a farm in the southern edge of the desert at temperatures from 15° to 45° Celsius.

When air temperatures hit 30.7° Celsius, the difference between beak surface temperature and air temperature spikes — indicating the birds were actively radiating heat through their beaks. At most, the birds lost about 25.1 watts per square meter through their beaks. Hornbills probably manage this cool trick by dilating the blood vessels to increase flow in their uninsulated beaks, the team writes May 18 in PLOS ONE.

Toucans lose about 60 percent of their total heat loss through their beaks, but hornbills only shed up to 20 percent of their heat loss through this method. The researchers chalk that difference up to larger beak-to-body-size in toucans.

Bacteria resistant to last-resort antibiotic appears in U.S.

A last-ditch weapon against drug-resistant bacteria has met its match in Pennsylvania.

A 49-year-old woman has tested positive for a strain of Escherichia coli resistant to the antibiotic colistin, researchers report May 26 in Antimicrobial Agents and Chemotherapy.

It’s the first time in the United States that scientists have found bacteria carrying a gene for colistin resistance known as mrc-1, write study coauthor Patrick McGann of Walter Reed Army Institute of Research in Silver Spring, Md., and colleagues.
But perhaps even more alarming is that the gene rides on a transferable loop of DNA called a plasmid.

“That means we now see a possibility of spread,” says physician and clinical microbiologist Robert Skov. And not just from mother cell to daughter cell, he says, but to neighboring strains of bacteria, too.

Bacteria carry most of their genetic information in a tangle of DNA contained in chromosomes inside the cell. But tiny loops of DNA called plasmids hang around outside of the tangle. These loops carry extra information that bacteria can use, like how to protect themselves from antibiotics. Bacteria can swap plasmids like trading cards, effectively spreading instructions for antibiotic resistance.

In December, Skov and colleagues discovered a Danish patient carrying bacteria with mcr-1 plasmid DNA, like the woman in Pennsylvania. And in November of 2015, researchers reported something similar in China.

Until then, all known colistin resistance was due to tweaks in chromosomal DNA (which, unlike plasmid DNA, isn’t easily spread among bacteria), says Skov, of the Statens Serum Institut in Copenhagen, who was not involved with the new work.

Colistin, a 50-year-old drug that doctors largely stopped prescribing in the 1970s because of its side effects, has made a comeback in the last five to 10 years. It’s used when other antibiotics fail; it’s a treatment option for people infected with multidrug-resistant bacteria. Now, with colistin-resistant bacteria, Skov says, antibiotic treatment options are becoming more and more limited.

The problem, scientists have been pointing out for years, is that people are taking antibiotics too frequently. More use means more opportunity for bacteria to develop resistance.

Still, even with colistin-resistant bacteria emerging all over the world, Skov says he doesn’t expect thousands of people to become infected.

“The scenario now is that once in a while, we’ll see a patient carrying bacteria that we don’t have any good antibiotics left for.” But that, he adds “is dreadful enough.”

Refined ‘three-parent-baby’ procedure improves chances for healthy infant

Improvements in a technique for making “three-parent babies” could reduce the risk of passing on faulty mitochondria, the energy-producing organelles in cells.

Less than 2 percent of mitochondria were defective in most human embryos created from this refined “pronuclear transplantation” procedure, researchers report online June 8 in Nature.

Pronuclear transplantation is one of two ways to transfer nuclear DNA from a mother’s egg that has faulty mitochondria to a donor egg with healthy mitochondria. After fertilization, the mother’s and father’s chromosomes don’t merge but are encased in separate membranes inside the mother’s egg. In pronuclear transplantation, researchers remove both of these DNA packages, known as pronuclei, and inject them into an empty donor egg.
Any resulting children would inherit DNA from three parents: most from their mother and father, with a small amount of mitochondrial DNA from the egg donor. DNA transplant techniques may prevent mothers from passing mitochondrial diseases to their children. Such diseases, which result from mutations in mitochondrial DNA, particularly affect energy-hungry organs, including the brain and muscles.

Last month, researchers reported that even small amounts of defective mitochondria carried into the healthy egg might propagate and negate the effect of the therapy (SN Online: 5/19/16).

In the new study, flash-freezing the mother’s egg, removing pronuclei soon after they form (about eight hours after fertilization) and other refinements greatly reduced the amount of defective mitochondria transplanted into donor eggs. Of embryos created, 79 percent carried less than 2 percent of defective mitochondria, report reproductive biologist Mary Herbert of the Wellcome Trust Centre for Mitochondrial Research in Newcastle upon Tyne, England, and colleagues.

That decrease in defective mitochondria doesn’t eliminate the risk of disease resurgence, but greatly reduces it, says Herbert. “The focus of our current research is to get that carryover as close to zero as we possibly can.”

Molecular handedness found in space

SAN DIEGO — A clue about why life on Earth chooses only one mirror-image form of certain molecules might lie in a gas cloud tens of thousands of light-years away.

For the first time, researchers have detected a chiral molecule, propylene oxide, in interstellar space. Chiral molecules, which come in two mirror-image versions, show up in many of life’s building blocks, such as the amino acids that make up proteins as well as sugars. The finding may be a step toward understanding why life prefers one of these versions over another.
The results were presented June 14 at a meeting of the American Astronomical Society and published online the same day in Science.

Chiral molecules are like opposing hands. Left hands and right hands mirror each other, but no amount of turning will get them to match when overlaid. Matching configurations of a chiral molecule are labeled as either left-handed or right-handed.

Amino acids and sugars come in both styles of handedness. But life on Earth exclusively uses left-handed amino acids and right-handed sugars. “This is one of the longest standing mysteries in the origin of life,” Brett McGuire, a chemist at Caltech, said at a news briefing.

Chiral molecules have shown up in meteorites with a slight preference for one configuration. McGuire and colleagues went looking for chiral molecules in space to see whether some interstellar intervention could preferentially seed a solar system with one handedness. The researchers sifted through radio observations from the Green Bank Telescope in West Virginia of a gas cloud dubbed Sagittarius B2. The nebula sits near the center of the galaxy and has historically been a rich hunting ground for interstellar molecules.

McGuire and colleagues found that the cloud was loaded with the chiral molecule propylene oxide. The stockpile has a mass equal to about 80 percent of Earth’s mass, said McGuire, and if compressed into a liquid blob, it would occupy a volume over five times that of our planet. The observations don’t reveal whether the cloud has a preference for one handedness over another; that will have to wait for future observations. But “we’re in the best position we could possibly be,” said McGuire, to figure out if life’s chiral exclusivity has an interstellar origin.

Earth has a tiny tagalong, and no, it’s not a moon

KWAH-zee-SAT-ah-lite n.
A body that orbits the sun and appears to orbit Earth.

Asteroid 2016 HO3 appears to orbit Earth, but that’s just an illusion. As the space rock loops around the sun, it plays leapfrog with our planet, sometimes speeding ahead sometimes falling behind. The asteroid’s suncentric orbit keeps it from qualifying as a full-fledged moon of Earth, but its constant proximity to us is enough to make it the only known “quasisatellite” of our world.
This temporary tagalong was discovered on April 27 in images from the Pan-STARRS observatory in Hawaii. The asteroid’s orbit around the sun is similar to Earth’s — one year on 2016 HO3 is just about 16 hours longer than an Earth year. Earth’s gravity keeps the asteroid from wandering; it never strays farther than about 400 million kilometers from Earth and never comes closer than about 14 million kilometers (38 times Earth’s distance to the moon).

The tiny rock — no more than about 100 meters across — has probably tagged along with Earth for about a century, and orbital calculations suggest that it will continue to do so for several centuries to come.

Nuclear bomb debris can reveal blast size, even decades later

A new type of fallout forensics can reconstruct nuclear blasts decades after detonation. By measuring the relative abundance of various elements in debris left over from nuclear explosions, researchers say they can accurately estimate the amount of energy released during the initial blast.

As proof of concept, the researchers estimated the yield of the 1945 Trinity nuclear test in New Mexico — the world’s first detonation of a nuclear device. The work pegged the explosion as equivalent to 22.1 kilotons of TNT, close to the official estimate of 21 kilotons. Applying the method to modern blasts could help regulators identify nuclear tests long after the fact and better enforce nonproliferation treaties, the researchers propose in a paper to appear in the Proceedings of the National Academy of Sciences the week of July 4.
Regulators currently monitor nuclear tests by detecting tremors and radioactive material emanating from blasts. Those effects are short-lived, however, so the techniques can only be used within a few days or weeks of a test.

Chemist Susan Hanson and colleagues at New Mexico’s Los Alamos National Laboratory looked at the element molybdenum in glassy debris created by the Trinity test. Stable molybdenum forms when zirconium from the bomb’s fireball radioactively decays. The relative abundance of different molybdenum isotopes created from this process differs from that found naturally. By measuring the overabundance of certain molybdenum isotopes, researchers can determine the original amount of zirconium created by the explosion. Pairing the amount of remnant plutonium in the debris with the zirconium estimate, the researchers can estimate a blast’s explosive yield.

The Los Alamos group declined to comment on the method’s usefulness for measuring the yield of more recent nuclear tests, such as the test North Korea conducted in January (SN Online: 1/6/16).

Black hole born without stellar parent, evidence suggests

A remote galaxy might harbor a type of black hole that arises directly from a massive cloud of gas rather than forming after the death of a star. This rare specimen could explain how some galaxies built gargantuan black holes in the first billion years or so after the Big Bang.

The galaxy, known as CR7, is unusual (SN: 7/25/2015, p. 8). It blasts out more ultraviolet radiation than other galaxies that lived at the same time, roughly 13 billion years ago (about 800 million years after the Big Bang). The gas in CR7 also appears to lack elements such as carbon and oxygen, which are forged within stars and then ejected into space. One idea is that CR7 is giving birth to first-generation stars, similar to the first stars ever created in the universe. Another hypothesis is that CR7 harbors the first known “direct collapse” black hole, one that forms when a blob of interstellar gas collapses under its own weight without first forming stars.
A black hole is more likely, suggest Aaron Smith of the University of Texas at Austin and colleagues in the Aug. 11 Monthly Notices of the Royal Astronomical Society. The researchers developed computer simulations that explore how interstellar gas interacts with the harsh radiation from primordial stars or a large black hole. Smith and colleagues find that the light from a cache of hot, young stars can’t explain why a parcel of gas is racing away from CR7 at about 580,000 kilometers per hour. What can push the gas, they report, is radiation from a superheated disk of debris swirling around a black hole roughly 100,000 times as massive as the sun.

If CR7 does host a black hole, it would be the first evidence of one forming out of clouds that haven’t given birth to stars yet. Astronomers struggle to explain how some supermassive black holes could form in about 1 billion years out of just smaller black holes merging together. “There’s just not enough time to do that,” Smith says. A direct collapse black hole, however, creates a massive seed all in one go, jump-starting the growth of a behemoth that will eventually weigh as much as several billion suns.

“This is definitely a good step forward,” says David Sobral, an astrophysicist at Lancaster University in England who discovered CR7 in 2015. But it’s too early to say whether a black hole or a group of stars is powering CR7, he says. “I’ve tried to stay a bit away from it and argue that what we need is new observations instead of taking sides.”

With the data that are available, it’s hard to distinguish between stars or a black hole, says Sobral. That’s why he and colleagues have reserved time with the Hubble Space Telescope in January and are awaiting new data from the Atacama Large Millimeter/submillimeter Array in Chile. Data from both observatories will help researchers look for traces of heavy elements in CR7. If these more sensitive data still show no sign of atoms such as carbon, says Sobral, then CR7 probably hosts a nest of first-generation stars. A black hole, on the other hand, probably would have formed long enough ago that there would be enough time for stars to form and pollute CR7 with a smidgen of heavy elements, he says.

A growing census of similar locales will help as well. “We’re now finding that CR7 is not alone,” Sobral says. He and his colleagues have since found four other galaxies comparable to CR7 in the early universe, results presented June 27 at the National Astronomy Meeting in Nottingham, England. “We don’t have to discuss one single thing,” he says, “but we can put [CR7] into a broader picture.”

Website tests predictive powers of the hive mind

As the saying goes, “It’s difficult to make predictions, especially about the future.” The website Metaculus.com aims to make this challenging task easier by harnessing collective wisdom.

Metaculus solicits answers to questions about the future — on topics spanning science, politics and economics — and combines these predictions to infer the likely outcomes. Will 2016 be the hottest year yet recorded? Will we find evidence for aliens soon? Will we hail self-driving taxis in the next few years? The hive mind might provide answers.
The website, created by physicists Anthony Aguirre and Gregory Laughlin of the University of California, Santa Cruz, along with former postdoc Max Wainwright, is an experiment to test whether our pooled instincts can produce reliable predictions. The site may also help scientists make informed decisions about which research to prioritize. Organizations funding research on pandemics, for instance, might want to know whether people are more concerned about bioterrorism, powerful germs escaping laboratories or naturally circulating diseases like the flu.

There’s a precedent for successful crowdsourcing of predictions. A U.S. government–funded geopolitical forecasting effort, the Good Judgment Project, has found that collective predictions can be remarkably accurate, and that prediction is a skill that can be honed.

After completing a free sign-up process, Metaculus users click through yes-or-no questions and make predictions, moving a slider from zero to 100 percent to indicate their level of certainty. The site provides relevant background information on each question, and additional research is encouraged. Prognosticators can hash things out in the comments section and share resources to help others make their predictions. Users rack up points — and bragging rights — when their predictions turn out to be correct.

The hive mind isn’t perfect — Metaculus users pegged the probability that the United Kingdom would vote to leave the European Union at just 32 percent. The United Kingdom did vote to leave, but that doesn’t mean the method is flawed. “The point of this is not to get a ‘yes’ or ‘no,’ ” Aguirre says, “but to get what is the probability.” Most events aren’t predictable with complete certainty, he says, but attaching a probability to such events can be useful in planning for the future.

So far, Metaculus has about 1,300 registered participants. In a review of more than 2,000 user predictions, the results were about as expected. When users predicted an event would happen with 80 percent certainty, they were correct about eight times out of 10. When many minds join forces, even nonexperts may collectively become capable guesstimators.

Smart mice have better odds of survival

Pinky and The Brain‘s smarts might not be so far-fetched. Some mice are quicker on the uptake than others. While it might not lead to world domination, wits have their upside: a better shot at staying alive.

Biologists Audrey Maille and Carsten Schradin of the University of Strasbourg in France tested reaction time and spatial memory in 90 African striped mice (Rhabdomys pumilio) over the course of a summer. For this particular wild rodent, surviving harsh summer droughts means making it to mating season in the early fall.

The team saw some overall trends: Females were more likely to survive if they had quick reflexes, and males were more likely to survive if they had good spatial memory. Cognitive traits like reacting quickly and remembering the best places to hide are key to eluding predators during these tough times but may come with trade-offs for males and females. The results show that an individual mouse’s cognitive strengths are linked to its survival odds, suggesting that the pressure to survive can shape basic cognition, Maille and Schradin write August 3 in Biology Letters.

Mix of brain training, physical therapy can help paralyzed patients

Training the brain could give paraplegics more control over their bodies.

After a year working with devices that link machine to brain, people paralyzed by spinal cord injuries were able to regain some movement and feeling in their legs, Miguel Nicolelis and colleagues report August 11 in Scientific Reports.

The training included an assortment of therapies with futuristic-looking gizmos, including virtual reality goggles and robotic exoskeletons that fasten over the body. All patients were better able to sense pain and touch, and half had their diagnosis upgraded from complete to partial paralysis.
“This is a very key milestone in the field of brain-machine interfaces,” Nicolelis said in a news briefing August 9.

But some scientists aren’t convinced that it’s such an advance.

Researchers have already proposed (and demonstrated) the benefits of brain-machine interface technology before, says Brendan Allison, a neuroscientist at the University of California, San Diego. While the new work is impressive and stands out for such long-term brain training, he says, “it’s simply not a breakthrough.”

Paralyzing spinal cord injuries can sever the bundle of nerves that carries messages from the brain to the body. So even if the brain tells the toes to move, the message dead-ends when it hits the injury site. For people with these severe injuries, there’s not much doctors can do to help, said Nicolelis, of Duke University. “They basically just try to get you adapted to life in a wheelchair.”

In 2012, he and colleagues started a project to help paraplegics walk, with assistance. With a stretchy cap placed over their heads to capture brain signals, patients would use their thoughts to control an exoskeleton, a robotic walker that held their bodies upright. The device would give paraplegics some mobility again — at least that was the goal. What the team found was far more exciting, Nicolelis said.
For one year, Nicolelis’ team worked with eight people who had been paralyzed for between three and 13 years. Twice a week for one hour, patients trained on a variety of rehabilitation tools. They learned how to control an avatar in virtual reality by imagining moving their legs, and later, how to use the brain-controlled exoskeleton. Patients also did hours of traditional physical therapy, including strengthening and stretching exercises.
About seven months into the project, the researchers noticed that all patients were beginning to regain control of one or more muscles below their spinal cord injury. And after 12 months, all patients experienced improvements in sensing touch and pain. One woman even gave birth to a child, and could feel the contractions during the delivery, Nicolelis said.

Though all patients had severe spinal cord injuries, he thinks some nerve cells must have survived and that the training rekindled their activity.

The amount of clinical recovery “is almost like a dream,” Nicolelis said. It may be enough to upgrade brain-machine interfaces, he said, from an assistive therapy (something that helps people walk — like crutches or a cane) to something that actually that helps people recover.

Again, that’s not a new idea, says Donatella Mattia, a neurophysiologist at the Institute for Research and Health Care in Rome. Other scientists working with paralyzed stroke patients have already shown improvements in arm mobility after using brain-machine interfaces.

What’s more, teasing out cause and effect in the new study isn’t easy, says University of Houston neural engineer José Contreras-Vidal. Patients underwent a complicated blend of therapies, with different lengths of training. Despite the caveats, though, he thinks the work is a step forward. And in clinical research, he says, “even incremental is good.”