Science’s inconvenient (but interesting) uncertainties

Earth sciences reporter Thomas Sumner recalls seeing the documentary film An Inconvenient Truth when he was in high school. The climate science presented in the movie didn’t surprise him too much — a science-minded student, he had already read about many of the issues. But, he says, the film started a broader dialog about global warming.
“People started caring,” he says, noting that he remembers his own family talking about it (and not always harmoniously) at the time. Revisiting the dramatic predictions made in the film proved an interesting journey for Sumner.
“The main criticism I heard was that the film had watered down the science,” he says. Climate science is amazingly complex, and so is modeling effects of change — from how much sea level might rise to how a warming climate could alter hurricane patterns. Even more striking to Sumner were the sheer number of uncertainties that remain. Those uncertainties are not about whether the climate is changing, but about the details of what such changes will mean for the oceans, the atmosphere and the living things on land — and when the various dominoes might fall. Telling the future is hard, especially about interrelated complex systems, but as Sumner reveals in his story, scientists have made steady progress in the last decade.

Another interesting point is the documentary’s (and Al Gore’s) role in politicizing climate science, which is fair to assume was one of the aims. “Gore was polarizing,” Sumner says. “He created a conversation about global warming, but he also cemented it as a political issue.”

Teeth and gums are neither political nor talked much about. But, as contributing correspondent Laura Beil reports, scientists studying a possible role for gum disease in what ails the body must contend with a slew of uncertainties, not unlike those faced by climate scientists. The bacteria that cause gum disease, some studies find, can travel to the arteries, heart, brain and other sites where they can cause havoc. Not all studies agree, and proving the oral bacteria–disease link beyond a doubt may not yet be within scientists’ grasp. But the fix is relatively simple, even if avoided by many: frequent flossing and regular visits to the dentist.

Keeping things simple was the underlying goal of the team of scientists attempting to build, from scratch, a synthetic organism with the least possible number of genes, as Tina Hesman Saey reports. After many tries, the effort succeeded, but not without first humbling the researchers involved. In the initial attempts, their computer-designed minimal genomes didn’t take. What ultimately worked was putting back some of the unknowns — genes with no known cellular job to do. Only then did the DNA inserted into the shell of a microbial cell yield a synthetic microbe capable of growing and reproducing.

Telling a good story about complex science, whether in a film or in a report on the latest research, requires some simplification. But sometimes the most interesting part lies in the uncertainty.

A weasel has shut down the Large Hadron Collider

CERN’s Large Hadron Collider is in standby mode after a 66-kilovolt/18-kilovolt electrical transformer suffered a short circuit April 29 at 5:30 a.m. Central European Time. The culprit: A small wild animal, believed to be a weasel, gnawing on a power cable.

“The concerned part of the LHC stopped immediately and safely, though some connections were slightly damaged due to an electrical arc,” Arnaud Marsollier, who leads CERN’s press office, wrote in an e-mail to Science News.

Sadly, the weasel did not survive the event, but the LHC should be back online soon. “It may take a few days to repair but such events happened a few times in the past and are part of the life of such a large installation,” Marsollier writes. The power outage comes just as the LHC is preparing to resume collecting data.

This isn’t the the first time an odd event has stalled operations at the particle collider outside Geneva on the Swiss-French border. In 2009, a piece of bread (supposedly a baguette dropped by a bird or from an airplane) interrupted a power installation for an LHC cooling unit.

Heartburn drugs can damage cells that line blood vessels

A popular type of heartburn medicine could hasten wear and tear of blood vessels.

Proton pump inhibitors, or PPIs, gunk up cells that typically line the veins and arteries like a slick coat of Teflon, researchers report May 10 in Circulation Research. Excess cellular junk ages the cells, which could make blood vessels work less smoothly.

The results, though controversial, are the first inkling of evidence that might explain why PPIs have recently been linked to so many different health problems, from heart attacks to dementia.
“The authors present a compelling story,” says Ziyad Al-Aly, a nephrologist at the Veterans Affairs Saint Louis Health Care System in Missouri. It begins to outline how using PPIs could spell trouble later on, he says. But Al-Aly notes that the study has one big limitation: It was done in cells, not people.

Gastroenterologist Ian Forgacs from King’s College Hospital in London agrees. Drawing conclusions about humans from cells grown in the lab requires “a huge leap of faith,” he says. So far, scientists have found only correlations between PPIs and their alleged side effects. “We need to know whether these drugs really do cause dementia and coronary disease and renal disease,” he says.

In the last few decades, proton pump inhibitors have emerged as a kind of wonder drug for heartburn. The drugs switch off molecular machines that pump acid into the stomach. So less acid surges up to burn the esophagus.

In 2012, nearly 8 percent of U.S. adults were taking prescription PPIs, according to a survey published last year in JAMA. (Some PPIs are also available over-the-counter.) Many people use PPIs for longer than they’re supposed to, says study coauthor John Cooke, a cardiologist at Houston Methodist Research Institute in Texas. “These are very powerful drugs­ — they’re not Tums,” he says. “They have side effects.”

Several of these side effects are still under debate. And if PPIs do increase the risk of dementia, say, or kidney disease, no one knows how. So Cooke and colleagues explored what chronic exposure to the drugs, which travel through the bloodstream, does to cells lining the blood vessels.
Human cells treated with a PPI called esomeprazole (sold as Nexium) seemed to age faster than untreated cells, the researchers found. The cells lost their youthful shape and instead “looked kind of like a fried egg,” Cooke says. They also lost the ability to split into new cells, among other signs of aging.

Cooke traced the rapid aging to mishaps in acid-filled cellular chambers called lysosomes. These chambers act as tiny garbage disposals; they get rid of junk like broken-down proteins. But PPIs, which work so well at shutting down acid production in the stomach, also seemed to shut down the acidic garbage disposals, too, the researchers found. That caused proteins to pile up, forming “little heaps of rubbish,” Cooke says.

Mucking with blood vessels’ lining could trigger all sorts of problems. For instance, instead of gliding easily through, platelets and white blood cells could get hung up, sticking to vessel walls like Velcro. “That’s how hardening of the arteries starts,” Cooke says.

The next step is to see if similar damage occurs in people. Doctors and regulatory agencies should take a second look at the widespread use of PPIs, too, Cooke says. “There’s enough data now that we have to be very cautious in our use of these agents.”

But some researchers think PPIs are getting a bum rap. “Everybody and their mother now want to hammer PPIs,” says gastroenterologist David Metz of the University of Pennsylvania. “It’s unfortunate because they’re spectacular drugs and they save people’s lives.”

The real question, Al-Aly says, is whether the benefits outweigh the risks.

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.”

Bacteria-sized molecules created in lab

Scientists have created giant molecules — the size of bacteria — that may be useful in future quantum computers.

The molecules of unusual size are formed from pairs of Rydberg atoms — atoms with an electron that has been boosted into a high-energy state. Such electrons orbit far from their atom’s nucleus and, as a result, can feel the influence of faraway atoms.

To create the molecules, researchers cooled cesium atoms nearly to absolute zero, hitting them with lasers to form Rydberg atoms that bound together in pairs. These molecules are about one thousandth of a millimeter in size — a thousand times the size of a typical molecule — scientists report August 19 in Physical Review Letters.
“I think it’s fundamentally interesting and important because it’s such a curious thing,” says physicist David Petrosyan of the Institute of Electronic Structure & Laser at the Foundation for Research and Technology–Hellas in Heraklion, Greece. “The size of these molecules is huge.”

This is not the first time such molecules have been created, but the previous evidence was not clear-cut. “Before, maybe it wasn’t clear if this is really a molecule in the sense that it’s vibrating and rotating. It could have been just two atoms sitting therewith very weak interactions or no interactions,” says Johannes Deiglmayr, a physicist at ETH Zürich and a coauthor of the study.

Deiglmayr and collaborators measured the molecules’ binding energies — the energy that holds the two atoms together. Additionally, the scientists made detailed calculations to predict the molecules’ properties. These calculations were “extensive and seemed to match really well with their measurements,” says physicist Phillip Gould of the University of Connecticut in Storrs.

The result has practical implications, Petrosyan notes. In quantum computers that use atoms as quantum bits, scientists perform computations by allowing atoms to interact. Rydberg atoms can interact with their neighbors over long distances, and when bound together, the atoms stay put at a consistent distance from one another — a feature that may improve the accuracy of calculations.

Previously, researchers have used rubidium atoms to make another type of large molecule, formed from Rydberg atoms bonded with normal atoms. But these wouldn’t be useful for quantum computation, Petrosyan says, as they rely on a different type of bonding mechanism.

How one scientist’s gut microbes changed over a year

Where you live and what you eat can rapidly affect the types of friendly bacteria inhabiting your body. To see how the microbes that inhabit the mouth and intestines change over time, Duke University computational biologist Lawrence David zealously chronicled his microbiome for an entire year. (For more on David and this experiment, see “Lawrence David’s gut check gets personal.”)

A stream plot (below, top graph) shows the ebb and flow of phyla of bacteria in his gut over time. The thickness of each stream indicates a bacterial group’s relative abundance in daily fecal samples.
David peered closer at the data in a horizon plot (above, bottom graph; colored squares at left indicate the phylum of the bacteria represented in each row). He first determined each type of bacteria’s normal abundance in his gut, then calculated how much they differed from the median abundance. Warmer colors (red, orange, yellow) indicate that bacteria in that group increased in abundance, and cooler colors (blue, green) indicate a decrease in abundance. Living abroad from day 71 to day 122 had a dramatic — but short-lived — effect on David’s microbiome.

Sugar industry sought to sugarcoat causes of heart disease

Using records unearthed from library storage vaults, researchers recently revealed that the sugar industry paid nutrition experts from Harvard University to downplay studies linking sugar and heart disease. Although the incident happened in the 1960s, it appears to have helped redirect the scientific narrative for decades.

The documents — which include correspondence, symposium programs and annual reports — show that the Sugar Research Foundation (as it was named at the time) paid professors who wrote a two-part review in 1967 in the New England Journal of Medicine. That report was highly skeptical of the evidence linking sugar to cardiovascular problems but accepting of the role of fat. The now-deceased professors’ overall conclusion left “no doubt” that reducing the risk of heart disease was a matter of reducing saturated fat and cholesterol, according to researchers from the University of California, San Francisco, who published their report online September 12 in JAMA Internal Medicine.

“Why does it matter today? The sugar industry helped deflect the way the research was developing,” says study coauthor Cristin Kearns, a dentist at UCSF’s Institute for Health Policy Studies. The Harvard team’s scientific favoritism had a role in directing research and policy attention toward fat and cholesterol. And in fact, the first dietary guidelines published by the federal government in 1980 said there was no convincing evidence that sugar causes heart disease, stating “the major health hazard from too much sugar is tooth decay.”
Following the publication of the Harvard report, fat and cholesterol went on to hijack the scientific agenda for decades, and even led to a craze of low-fat foods that often added sugar. Kearns points out that it was only in 2015 that dietary guidelines finally made a strong statement to limit sugar. Researchers writing this year in Progress in Cardiovascular Diseases note that current studies estimate that diets high in added sugars carry a three times higher risk of death from cardiovascular disease. (For its part, the Sugar Association says in a statement on its website that “the last several decades of research have concluded that sugar does not have a unique role in heart disease.”)

The level at which the food industry continues to influence nutrition research is still a much-debated topic. The Sugar Association’s statement acknowledged the secret deal occurred, but pointed out that “when the studies in question were published, funding disclosures and transparency standards were not the norm they are today.” Journals now require all authors to list conflicts of interest, especially funding from a source has a vested interest in the outcome.

That doesn’t mean that trade groups and industry associations no longer have an influence on scientists, says Andy Bellatti, cofounder and strategic director of Dietitians for Professional Integrity, which has campaigned to push the Academy of Nutrition and Dietetics to sever its ties with industry, While a modern researcher could not take corporate money, even for speaking fees, without disclosure, the influences may be more subtle, he says. “We’re not talking about making up data, but perhaps influencing how a research question is framed.”

In a commentary published with the JAMA study, Marion Nestle, a nutrition researcher at New York University, wrote that industry influence has not disappeared. She cited recent New York Times investigations of Coca-Cola–sponsored research and Associated Press stories revealing that a candy trade group sponsored research attempting to show that children who eat sweets have a healthy body weight.

Bellatti says that researchers don’t necessarily want to be cozy with industry, but sometimes turn to commercial sources because non-biased research money is lacking. “The reason the food industry is able to do this is because there is such little public funding for nutrition and disease,” Bellatti says.
For that reason, the scientific community should not reject industry money wholesale, says John Sievenpiper, a physician and nutrition researcher at the University of Toronto. A study of his was once ridiculed on Nestle’s blog because the disclosures covered two full pages. He believes that any scientist who takes industry money should adhere to an even higher standard of openness, including releasing study protocols ahead of time so reviewers can make sure the research question was not changed midstream to favor a certain conclusion.

While many parallels have been made between the food and tobacco industries, Sievenpiper believes those comparisons miss the complicated nature of the human diet. Tobacco is always bad, never good. Sugar, fat, cholesterol and other components of diet are some of both, making research into their effects much more nuanced, he says. And unlike with tobacco, the solution can’t be to never eat them. He believes solutions won’t involve turning single nutrients like fat or sugar into villains, but promoting better overall patterns of eating, like the Mediterranean diet.

Kearns, who has spent the past 10 years looking into the sugar industry’s influence on science, isn’t finished yet. She says her curiosity first arose during a conference on gum disease and diabetes in 2007, when she noticed a lack of scientific discussion of sugar. She started out simply Googling industry influences. The trail eventually led her to scour library archives, until she came across dusty boxes of records from a closed sugar company in Colorado. “The first page I looked at in that archive had a confidential memo,” she says. “I knew I had something no one else had never talked about before.”

She doesn’t see the research going sour any time soon. “This was their 226th project in 1965,” she says. “There’s a lot more to the story.”

There’s a new way to stop an earthquake: put a volcano in its path

Editor’s note: Science has retracted the study described in this article. The May 3, 2019, issue of the journal notes that a panel of outside experts convened by Kyoto University in Japan concluded in March 2019 that the paper contained falsified data, manipulated images and instances of plagiarism, and that these were the responsibility of lead author Aiming Lin, a geophysicist at Kyoto University. In agreement with the investigation’s recommendation, the authors withdrew the report.

A titanic volcano stopped a mega-sized earthquake in its tracks.

In April, pent-up stress along the Futagawa-Hinagu Fault Zone in Japan began to unleash a magnitude 7.1 earthquake. The rupture traveled about 30 kilometers along the fault until it reached Mount Aso, one of Earth’s largest active volcanoes. That’s where the quake met its demise, geophysicist Aiming Lin of Kyoto University in Japan and colleagues report online October 20 in Science. The quake moved across the volcano’s caldronlike crater and abruptly stopped, the researchers found.

Geophysical evidence suggests that a region of rising magma lurks beneath the volcano. This magma chamber created upward pressure plus horizontal stresses that acted as an impassable roadblock for the seismic slip powering the quake, the researchers propose. This rare meetup, the researchers warn, may have undermined the structural integrity surrounding the magma chamber, increasing the likelihood of an eruption at Aso.

Young planets carve rings and spirals in the gas around their suns

Growing planets carve rings and spiral arms out of the gas and dust surrounding their young stars, researchers report in three papers to be published in Astronomy & Astrophysics. And dark streaks radiating away from the star in one of the planet nurseries appear to be shadows cast onto the disk by the clumps of planet-building material close to the star. This isn’t the first time that astronomers have spied rings around young stars, but the new images provide a peek at what goes into building diverse planetary systems.

The three stars — HD 97048, HD 135344B and RX J1615.3-3255 — are all youthful locals in our galaxy. They sit between 460 and 600 light-years away; the oldest is roughly a mere 8 million years old. All the stars have been studied before. But now three teams of researchers have used a new instrument at the Very Large Telescope in Chile to see extra-sharp details in the planet construction zone around each star.

The new instrument, named SPHERE, was designed to record images, spectra and polarimetry (the orientations of light waves) of young exoplanet families. Flexible mirrors within the instrument adapt to atmospheric turbulence above the telescope, and a tiny disk blocks light from the star, allowing faint details around the star to come into view.