Global air pollution shortens lifespan by average of three years

Air pollution shortens the average human lifespan by three years, according to new models. Photo by PublicDomainPictures/Pixabay

March 3 (UPI) -- Air pollution is a greater drag on the average human lifespan than war, malaria, HIV/AIDS, smoking and more.

In a new study, published Tuesday in the journal Cardiovascular Research, an international team of scientists used a novel modelling technique to estimate the effects of different types of air pollution on death rates around the world.

Simulations showed global air pollution was responsible for 8.8 million premature deaths in 2015, shortening human life expectancy an average of three years. By comparison, smoking tobacco shortened life expectancy by 2.2 years. Diseases spread by parasites or insects like mosquitoes, ticks and fleas shortened life expectancy by a little more than half a year.

Using the results of previous scientific studies as their guide, the creators of the new model tabulated the impacts of air pollution on six different types of disease: lower respiratory tract infection, chronic obstructive pulmonary disease, lung cancer, heart disease, stroke-causing cerebrovascular disease and other non-communicable diseases like high blood pressure and diabetes.


The data showed the effects of air pollution on cardiovascular diseases -- heart disease and cerebrovascular disease -- is responsible for 43 percent of the reduction in global life expectancy.

"Air pollution causes damage to the blood vessels through increased oxidative stress, which then leads to increases in blood pressure, diabetes, stroke, heart attacks and heart failure," lead study author Jos Lelieveld, climate scientist at the Max Planck Institute for Chemistry in Germany, said in a news release.

The new models also revealed 75 percent of the premature deaths caused by air pollution occurred in people over the age of 60.

"It is remarkable that both the number of deaths and the loss in life expectancy from air pollution rival the effect of tobacco smoking and are much higher than other causes of death," said Lelieveld. "Air pollution exceeds malaria as a global cause of premature death by a factor of 19, it exceeds violence by a factor of 16, HIV/AIDS by a factor of 9, alcohol by a factor of 45, and drug abuse by a factor of 60."

Authors of the new study argued air pollution -- and its significant negative impacts on human health -- warrants the term "pandemic."

"Since the impact of air pollution on public health overall is much larger than expected, and is a worldwide phenomenon, we believe our results show there is an 'air pollution pandemic,'" said Thomas Münzel, cardiovascular researcher at the University Medical Center of the Johannes Gutenberg University in Germany. "Policy-makers and the medical community should be paying much more attention to this. Both air pollution and smoking are preventable, but over the past decades much less attention has been paid to air pollution than to smoking, especially among cardiologists."

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The research distinguished between air pollution caused by human activities and air pollution caused by natural phenomena, like wildfire emissions and dust blown into the air by desert winds.

Around the world, human-caused pollution, mostly from the burning of fossil fuels, accounted for two-thirds of premature deaths. In the wealthiest countries, human-caused pollution accounted for 80 percent of premature deaths.

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New drug prevents bacteria from acquiring antibiotic resistance genes

Postdoctoral researcher Arnau Domenech and his colleagues identified a new pathway for disrupting the ability of bacteria cells to develop antibiotic resistance. Photo by Veening Lab

March 3 (UPI) -- According to a new study, scientists have developed a drug that prevents bacteria from acquiring the genes needed to develop antibiotic resistance.

Bacteria evolve resistance to antibiotics by acquiring DNA fragments from their environs and incorporating them into their genomes. This ability is referred to as "competence."

Through a series of observations and lab tests, scientists were able to identify the chain of events that allow bacteria cells to become competent. Once they identified what competence looked like, scientists were able to identify drugs that interfered with the process.

"We collaborated with scientists from Heidelberg, who developed a high-throughput assay to simultaneously test cells for competence and growth," lead study author Arnau Domenech, postdoctoral researcher at the University of Groningen in the Netherlands, said in a news release. "In this assay, 1,366 approved drugs were screened. It turned out that 46 of them blocked the induction of competence, without negatively affecting growth."

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Cells can become motivated to evolve defenses against drugs if the drugs cause growth stress. Because the 46 drugs don't negatively impact cell growth, cells of the bacterium Streptococcus pneumoniae didn't develop resistance.

The drugs that prevented competence and didn't inhibit cell growth belonged to two different categories: drugs affecting ion homeostasis and antipsychotics. Further investigation showed that all of the drugs block competence by disrupting the proton-motive force, the electrochemical gradient that propels protons cellular membranes and fuels a variety of cellular processes.

"The result is that the cells fail to secrete a peptide called CSP," said Domenech.

When enough cells secrete CSP, competence genes get activated -- a process known as quorum sensing. By disrupting the proton-motive force, the 46 drugs prevented CSP secretion from crossing the necessary threshold and turning on the competence genes.

"In the lab, we observed that our competence-blocking drugs could prevent the transfer of antibiotic resistance genes to susceptible strains of Streptococcus pneumoniae and we obtained the same results in cultures of human lung epithelial cells," Domenech said.

Scientists got the same promising results when they repeated the lab tests using a mouse model. The research team published the results of their tests this week in the journal Cell Host and Microbe.

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Because the proton-motive force is necessary for some vital functions in humans, scientists aren't certain whether drugs are safe for humans. Further testing is needed to determine whether these anti-evolution drugs can help

ULTIMATE BREEDER
Swamp wallaby never stops being pregnant

Female swamp wallabies are constantly pregnant during adulthood.

Photo by Wikimedia/CC

March 4 (UPI) -- The female swamp wallaby, native to eastern Australia, is the only mammal that remains pregnant for the entirety of adulthood, according to a new study.

Like kangaroos, wallabies have two uteri. During the later stages of a swamp wallaby's most immediate pregnancy, a new embryo forms in the unused uterus. When the wallaby gives birth and the newborn joey starts suckling milk, the new embryo enters a long period of developmental arrest called embryonic diapause.

When the young wallaby's appetite for milk starts to wane, the embryo begins growing once more and the pregnancy cycle starts anew. The female wallaby becomes fertile and she seeks out a new mate to form a second embryo.

"Thus, females are permanently pregnant their whole lives," lead researcher Brandon Menzies, geneticist and marsupial expert at the University of Melbourne, said in a news release.

Most mammals need a break in between pregnancies to help raise newborns or avoid seasonal dips in food resources, but the latest research -- published this week in the journal PNAS -- suggests the female swamp wallaby never takes a day off from being pregnant.

"We used high resolution ultrasound to track pregnancy and mating in 10 female swamp wallabies," said Menzies. "What we found amazed us: the females come into oestrus, mate and form a new embryo 1 to 2 days before the end of their existing pregnancy. The swamp wallaby is the only mammal known to be continuously pregnant in this way."

Because the swamp wallaby is always pregnant, moms are always supporting three different stages of development: an embryo in the uterus, a young joey in the pouch and a semi-dependent young still suckling milk. Despite these heavy demands on female swamp wallabies, surveys suggest the species is doing well.

"Whatever the reason, the swamp wallaby is an incredibly successful and ubiquitous species in Australia, occupying a range that stretches from the Western Victoria/South Australian border all the way up the eastern seaboard to cape York in far north Queensland," said Menzies.


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Sex chromosomes explain shorter lifespans of male mammals

Male mammals tend to lead shorter lives than their female

counterparts, at least in part due to their Y chromosome. 

Photo by Piqsels/CC

March 4 (UPI) -- According to a new study, male mammals live shorter lives than their female peers as a result of sex chromosomes, not because of their risky behavior.

When an international team of researchers surveyed the scientific literature for links between sex chromosomes and lifespan across the animal kingdom, they found evidence supporting the "unguarded X hypothesis."

The unguarded X hypothesis supposes that males, because they have an X and Y chromosome, are less able to avoid harmful genes expressed on the X chromosome. Because the Y chromosome is often smaller than the X, it can's hide the flaws in the X chromosome.

Having two X chromosomes is beneficial because the homogametic chromosomes can be interchanged, with a healthy X chromosome taking the place of an X that has damaging genes.

Researchers found broad support for the hypothesis in available scientific literature. They published findings Wednesday in the journal Biology Letters.

"We looked at lifespan data in not just primates, other mammals and birds, but also reptiles, fish, amphibians, arachnids, cockroaches, grasshoppers, beetles, butterflies and moths among others," lead study author Zoe Xirocostas, doctoral student at the University of New South Wales, said in a news release. "And we found that across that broad range of species, the heterogametic sex does tend to die earlier than the homogametic sex, and it's 17.6 percent earlier on average."

Male animals don't always carry heterogametic sex chromosomes. Female birds, butterflies and moths carry ZW chromosomes, while the males carry homogametic ZZ sex chromosomes. Data analyzed by Xirocostas and her colleagues showed female birds, butterflies and moths tend to die sooner than their male counterparts.

The difference in lifespans between the carriers of ZW and ZZ chromosomes wasn't as great, however.

"We found a smaller difference in lifespan between the males and females in the female heterogametic species compared to males and females in the male heterogametic species," Xirocostas said. "In species where males are heterogametic (XY), females live almost 21 percent longer than males. But in the species of birds, butterflies and moths, where females are heterogametic (ZW), males only outlive females by 7 percent."

The findings suggest chromosomal differences help explain some of differences in lifespan between male and female mammals, but it's possible that differences in behavior further shrink the male mammal's already shorter lifespan.

Farming encouraged cooperation and violence among early humans

Farming brought people together in larger concentrations,

 encouraging cooperation -- but also violence. 

Photo by Pexels from Pixabay

March 4 (UPI) -- As hunter-gatherers settled down and took to farming the land, groups of people began gathering in larger numbers and cooperating. But new research suggests the adoption of agriculture encouraged violence between humans populations, too.

"We were interested in understanding why people would make the shift from hunting and gathering to farming," Elic Weitzel, doctoral student in anthropology at the University of Connecticut, said in a news release. "Then I started to get interested in what happened in society after they made that shift and started farming on a larger scale."

Weitzel and his colleagues used "ideal free distribution" to simulate the distribution of farmers in in eastern North America between 7,500 and 5,000 years ago, as well as to locate the most coveted land -- the acreage with the most food, water, raw materials and shelter.

Scientists graded different land parcels with a "net primary productivity" score. The most productive pieces of land tended to host the largest concentration of people, and thus, host the greatest amount of conflict and violence.

"If you are living in a suitable area, you can lay claim and keep others from accessing what you have," Weitzel said. "That becomes a cooperative process, because one person is not as effective as a whole group is at defending a territory."

But scientists also found evidence of the so-called Allee's Principle, which posits increases in individual fitness boost the density of the population through cooperation.

"The transition from a hunting and gathering society to an agricultural society is dependent on collaboration," said co-author Stephen Carmody, an anthropologist at Troy University. "The development of agriculture appears to only have happened in nine places around the world so Eastern North America is a unique part of the world to study. Agriculture was one of the most consequential transitions that happened in the past. It changed our whole economic situation."

The concentration of valuable resources could only be accessed via cooperation and coordinated protection, but coveted land and resources also inspired jealousy and violence.

"When a resource like domesticated crops is dense and predictable, that is when we expect that it would be defendable," Weitzel said. "Other groups may want access to your crop in case their crop failed, for example. There is cooperation and there are aspects of competition. Harvesting and defending."

During the time period studied, scientists identified archaeological evidence of larger, more dense population centers, a sign of growing levels of cooperation among groups of humans. But researchers also found evidence of increased violence and trophy taking in the archaeological record.

"Of course there are signs of violence throughout history, but trophy-taking is a different type of violence," Weitzel said. "The victor removes a part of the loser as a signal they won. They took scalps, hands, feet, heads -- that first evidence appears to have happened at the same time as plant management."

Scientists were also able to see patterns predicted by Allee's Principle playing out in the archaeological record. As concentrations of humans grew, the land's suitability declined and groups began to disperse once more. A decline in trophy-taking violence declined during the period of dispersal.

Researchers suggest their findings -- published this week in the journal Environmental Archaeology -- could be used to better understand the effects of modern pressures, like climate change and economic inequality, on human behavior.

"This is one of the ways archaeology is relevant to contemporary and future society," Weitzel said. "The modeling of human behaviors in society and our relationships can help us overcome current collective action problems. We are all better off if we cooperate."

Light-activated coating kills bacteria

Scientists have developed a new coating that kills bacteria under ambient light conditions. Photo courtesy of University College London

March 5 (UPI) -- Scientists have developed a new light-activated coating that kills bacteria. The coating could be applied to phone screens and keyboards to curb the spread of harmful bacteria.

More importantly, the coating could be used on medical equipment like catheters and breathing tubes, the main sources of of healthcare-associated infections. The most common healthcare-associated infections are caused by Clostridioides difficile, methicillin-resistant Staphylococcus aureus, or MRSA, and E. coli.

In lab tests, the new antimicrobial coating successfully killed bacteria when exposed to low intensity, ambient light, the kind of light commonly found in hospital wards. The coating's antibacterial properties were activated by light levels as low as 300 Lux. Most light-activated antimicrobial coatings require lights as bright as 3,000 Lux.

Researchers created the coating by embedding chemically modified gold in a polymer with crystal violet, a medical dye boasting antibacterial and antifungal properties. The dye is also antihelmintic, which means it is hostile to small parasites.

Scientists described the novel coating Thursday in the journal Nature Communications.

"Dyes such as crystal violet are promising candidates for killing bacteria and keeping surfaces sterile as they are widely used to disinfect wounds," first author Gi Byoung Hwang, a chemist at University College London, said in a news release. "When exposed to bright light, they create reactive oxygen species, which in turn kill bacteria by damaging their protective membranes and DNA. This is amplified when they are paired with metals such as silver, gold and zinc oxide."

During the initial test phases, scientists found a control coating of crystal violet in a polymer was not enough to kill either S. aureus or E. coli bacteria under ambient light. However, the new bactericidal coating slowed the proliferation of each bacteria. Tests showed the coating took longer to curb E. coli growth.

"E. coli was more resistant to the bactericidal coating than S. aureus as it took longer to achieve a significant reduction in the number of viable bacteria on the surface," said Elaine Allan, UCL researcher and study co-author. "This is presumably because E. coli has a cell wall with a double membrane structure, whereas S. aureus only has a single membrane barrier."

The tests results showed the coating's production of hydrogen peroxide was responsible for killing the bacteria.

"The gold clusters in our coating are key to generating the hydrogen peroxide, through the action of light and humidity," said senior study author Asterios Gavriilidis, professor of chemical engineering at UCL. "Given the clusters contain only 25 atoms of gold, very little of this precious metal is required compared to similar coatings, making our coating attractive for wider use."

Researchers suggest the new coating could be incorporated into a variety of healthcare environments in the near future.

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Study confirms space-grown lettuce nutritious, safe

The crew aboard the International Space Station has grown batches of mixed greens -- mizuna, red romaine lettuce and Tokyo bekana cabbage -- and further research has found it is safe to eat, even though astronauts have already used it for salads. Photo by NASA/UPI | License Photo

March 6 (UPI) -- Astronauts onboard the International Space Station have successfully cultivated lettuce and, according to a study published Friday, the red romaine lettuce -- a Lactuca sativa variety known as 'Outredgeous' -- is disease-free and safe to eat.

Currently, astronauts must go without fresh produce. All of their meals are sterilized for the trip to space by heating, freeze drying or irradiation. Nutrients tend to degrade during long-term storage.

In addition to offering a reprieve from the monotony of freeze-dried meals, fresh lettuce would provide a nutritional boost. The red romaine lettuce contains potassium as well as vitamins K, B1, and C.

NASA officials have previously pinpointed growing crops in space as an essential part of long-term space missions, such as a human outpost on the moon or a trip to Mars.

"The ability to grow food in a sustainable system that is safe for crew consumption will become critical as NASA moves toward longer missions," lead study author Christina Khodadad, researcher at the Kennedy Space Center, said in a news release. "Salad-type, leafy greens can be grown and consumed fresh with few resources."

The lettuce was grown from surface-sterilized seeds inside a chamber specifically designed for space-based crops. Scientists outfitted the Vegetable Production Systems, dubbed "Veggie," with LED lighting and a watering system. The lettuce was allowed to grow undisturbed for 33 to 56 days before being deep-frozen and readied for shipment back to Earth.

Scientists grew a control crop at Kennedy Space Center's laboratories under conditions similar to those found inside the space station.

When they compared the harvests, scientists found the space lettuce was similar in composition. However, some of the space lettuce boasted higher concentrations of vitamins and other compounds, including potassium, sodium, phosphorus, sulphur and zinc. Researchers also measured elevated levels of phenolics in the space lettuce, molecules that boast antiviral, anticancer, and anti-inflammatory properties.

Researchers also used next-generation DNA sequencing technology to identify the communities of fungi and bacteria living on the space lettuce. They found the 15 most abundant microbial genera on the space lettuce leaves were similar to those living on the control crop. Fungi and bacteria living on the roots of the two crops were also similar. The sequencing revealed no bacteria genera known to cause disease in humans.

As scientists confirmed in the paper, published in the journal Frontiers in Plant Science, the red romaine lettuce grown on the International Space Station is safe to eat.

Astronauts already knew as much, anecdotally, as several space station crew members ate a salad before sending the rest of the harvest back to Earth for study. There were no ill effects. But the official findings bode well for the future of crop cultivation in space.

"The International Space Station is serving as a test bed for future long-duration missions, and these types of crop growth tests are helping to expand the suite of candidates that can be effectively grown in microgravity," said study co-author Gioia Massa, project scientist at Kennedy Space Center. "Future tests will study other types of leafy crops as well as small fruits like pepper and tomatoes, to help provide supplemental fresh produce for the astronaut diet."

Plastic found in amphipods in Earth's deepest ocean trench

Scientists found plastic fragments inside amphipods living between 3.7 and 4.3 miles beneath the ocean surface. Photo by Newcastle University

March 6 (UPI) -- Plastics are being ingested by amphipods living in one of the deepest places on Earth, the Pacific Ocean's Mariana Trench.

Amphipods, sometimes called hoppers, are tiny shrimp-like crustaceans. Though they are found in all aquatic environs, the majority of the roughly 9,900 known species are found in the ocean.

Recently, scientists found a new species living in the Mariana Trench, between Japan and the Philippines -- the ninth species in a genus of deep-sea amphipods. Scientists named the new species, Eurythenes plasticus, for the the contents of its digestive tract.

Inside the amphipod's body, scientists found polyethylene terephthalate, a synthetic compound used to make water bottles and workout attire. The plastic-eating amphipods were caught on baited lines between 3.7 and 4.3 miles beneath the ocean surface.

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The discovery, described this week in the journal Zootaxa, confirms what other studies have suggested, that plastics pollution has made its way to the deepest parts of the ocean.

"We decided on the name Eurythenes plasticus as we wanted to highlight the fact that we need to take immediate action to stop the deluge of plastic waste into our oceans," lead researcher Alan Jamieson, senior lecturer in marine ecology at Newcastle University in Britain, said in a news release.

Much of the world's plastic waste gets exported to Southeast Asia, where recycling efforts are often lackluster. Lots of the plastic gets burned or dumped at repositories, and some of that waste ends up washed into the ocean. Over time, big pieces of plastic get broken down into smaller bits.

Marine animals ingest plastic particles on accident or mistake pieces of plastic for food. Previous studies suggest some animals, including certain coral species, seem to prefer plastic to real food.

As the latest research proves, some of the plastic particles filter down to the deepest parts of the ocean, where it gets ingested by amphipods and other miniature organisms.

"The newly discovered species Eurythenes plasticus shows us how far-reaching the consequences of our inadequate handling of plastic waste truly is," said Heike Vesper, director of the marine program at the World Wildlife Fund in Germany. "There are species living in the deepest, most remote places on earth which have already ingested plastic before they are even known about by humankind. Plastics are in the air that we breathe, in the water that we drink and now also in animals that live far away from human civilization."

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Last year, the World Wildlife Fund initiated an international campaign for a global, legally binding treaty aimed at stopping plastic pollution from ending up the ocean.


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NASA: Boeing software team had too much power over Starliner capsule

The Boeing Starliner spacecraft was returned to Kennedy Space Center in Florida for refurbishment. File Photo by Joe Marino/UPI | License Photo

March 6 (UPI) -- Boeing's software team had too much influence over final decisions regarding the company's Starliner capsule, a top NASA administrator said Friday.

The finding was among 61 corrective actions NASA and Boeing have agreed to make before moving ahead with another Starliner mission. A test flight in December failed to reach the International Space Station, but landed successfully in New Mexico after two days in space.

NASA has not decided if it will require another test flight before sending astronauts aloft.

"We had delegated too much authority to the software board to approve changes and to approve actions as it applied to software," said Douglas Loverro, NASA's associate administrator for human exploration. "Those changes should have been brought up to the overall engineering review board."
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For example, software experts made a decision not to test all possible ways the software could respond to a given condition, Loverro said.

He also said Friday he had decided to formally classify the Boeing flight failure as a "high visibility close call," the lowest category NASA uses for serious mission problems.

Boeing and SpaceX are competing to become the first private company to fly astronauts on NASA missions. Boeing previously revealed that it had failed to detect problems with the capsule mission clock because it hadn't run full-length mission tests from launch to docking at the space station.

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The Starliner problems come as Boeing struggles to overcome serious safety issues with its Boeing 737 Max aircraft. Jim Chilton, senior vice president at Boeing Space and Launch, said he wasn't aware of any issues in common between Starliner and 737 Max.

However, Chilton added that the lessons learned from Starliner "are being applied across our enterprise."

Soldier ants prove evolution sometimes works in reverse

Turtle ant soldiers have evolved a variety of head shapes to block the entrance to their tunneled tree nests. Photo by Scott Powell/George Washington University

March 10 (UPI) -- Turtle ant soldiers have evolved a unique defensive strategy. These gate guards use their comically large heads to block entrances to their nests.

Some ants have round heads, like a manhole cover, ideal for blocking a small round entrance. Other ants, with square heads, congregate to form a blockade, like the wall of overlapping shields formed by Spartan armies.

Turtle ant soldiers seem like a perfect example of evolutionary specialization. The many species of the turtle ant genus occupy specific niches. But a new study of turtle ant soldiers suggests evolution doesn't only encourage specialization.

Instead, scientists uncovered evidence that evolution can promote regression toward a more generalist approach.

"Usually, you would think that once a species is specialized, it's stuck in that very narrow niche," Daniel Kronauer, head of the Laboratory of Social Evolution and Behavior at Rockefeller University, said in a news release. "But turtle ants are an interesting case of a very dynamic evolutionary trajectory, with a lot of back and forth."

Turtle ants make their homes in abandoned tunnels that were carved by wood-boring beetles. Different turtle ant species have evolved to occupy and defend different sized tunnels.

"There's a whopping four-fold difference between the smallest and largest turtle ant soldier heads," said Scott Powell, a biologist at George Washington University. "To help people picture this, I often say that the smallest species is able to sit comfortably on the head of the largest species."

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To better understand how turtle ants diversify to fill the various niches of uniquely sized tree tunnels, scientists classified different turtle ant species by the shapes of their soldiers' heads: square, dome, disc or dish-shaped. Next, scientist used genetic data to untangle the evolutionary relationship between different species.

If evolution moved in just one direction, turtle ants should have started out without specialized soldier. And the earliest soldiers should have boasted simple square heads. Highly specialized shapes should have come only later.

Scientists found the oldest turtle ant ancestor did have square-headed soldiers. As well, turtle ants and their soldiers quickly diversified to adapt to variety of tunnels with unusually shaped heads. However, many newer species have since reversed course, having evolved more generalized head shapes, allowing them to occupy a variety of tunnels.

The new research, published this week in the journal PNAS, suggests evolution is a two-way street.

"The space that evolution has to play with is actually quite a bit larger than previously thought," Kronauer adds.