Ancient amphibian had mouthful of teeth ready to grab you

A thematic diagram showing a cut across the skull showing the position of the denticulate plates that covered the soft palate. On the left is at resting stage, on the right, ventral movement of the soft palate by retraction of the eyeballs, during feeding

The idea of being bitten by a nearly toothless modern frog or salamander sounds laughable, but their ancient ancestors had a full array of teeth, large fangs and thousands of tiny hook-like structures called denticles on the roofs of their mouths that would snare prey, according to new research by paleontologists at the University of Toronto Mississauga (UTM).

In research published online in a recent issue of PeerJ, an open access journal, Professor Robert Reisz, Distinguished Professor of Paleontology at UTM, explains that the presence of such an extensive field of teeth provides clues to how the intriguing feeding mechanism seen in modern amphibians was also likely used by their ancient ancestors.

They believe that the tooth-bearing plates "were ideally suited for holding on to prey, such as insects or smaller tetrapods, may have facilitated a method of swallowing prey items via retraction of the eyeballs into the mouth, as some amphibians do today.

In many vertebrates, ranging from fish to early synapsids (ancestors of mammals), denticles are commonly found in dense concentrations on the bones of the hard palate (roof of the mouth). However, in one group of tetrapods, temnospondyls (which are thought to be the ancestors of modern amphibians) these denticles were also found on small, bony plates that filled the large soft part of the palate. The entire roof of the mouth was covered with literally thousands of these tiny teeth that they used to grab prey. Since these toothy plates were suspended in soft tissue, they are often lost or scattered during fossilization.

Denticles are significantly smaller than the teeth around the margin of the mouth -- on the order of dozens to a couple hundred microns in length. They are actually true teeth, rather than just protrusions in the mouths of these tetrapods, says Reisz and his colleagues, Bryan Gee and Yara Haridy, both graduate students in paleontology.

"Denticles have all of the features of the large teeth that are found on the margin of the mouth," says Reisz. "In examining tetrapod specimens dating back ~289 million years, we discovered that the denticles display essentially all of the main features that are considered to define teeth, including enamel and dentine, pulp cavity and peridontia."

In reaching these conclusions, the researchers analyzed specimens unearthed from the fossil-rich Dolese Brothers Limestone Quarry near Richards Spur, Oklahoma. They were extraordinarily well preserved, making them ideal candidates for study.

The researchers extracted and isolated the denticle-bearing plates, created thin section slides and examined them under the microscope -- no small feat since denticles on this animal were only about 100 microns long.

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Why we did not evolve to live forever: Unveiling the mystery of why we age

C. elegans.

Researchers at the Institute of Molecular Biology (IMB) in Mainz, Germany, have made a breakthrough in understanding the origin of the ageing process. They have identified that genes belonging to a process called autophagy -- one of the cells most critical survival processes -- promote health and fitness in young worms but drive the process of ageing later in life. This research published in the journal Genes & Development gives some of the first clear evidence for how the ageing process arises as a quirk of evolution. These findings may also have broader implications for the treatment of neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's disease where autophagy is implicated. The researchers show that by promoting longevity through shutting down autophagy in old worms there is a strong improvement in neuronal and subsequent whole body health.

Getting old, it's something that happens to everyone and nearly every species on this planet, but the question is, should it? In a recent publication in the journal Genes & Development titled "Neuronal inhibition of the autophagy nucleation complex extends lifespan in post-reproductive C. elegans," the laboratory of Dr Holger Richly at IMB, has found some of the first genetic evidence that may put this question to rest.

As Charles Darwin explained, natural selection results in the fittest individuals for a given environment surviving to breed and pass on their genes to the next generation. The more fruitful a trait is at promoting reproductive success, the stronger the selection for that trait will be. In theory, this should give rise to individuals with traits which prevent ageing as their genes could be passed on nearly continuously. Thus, despite the obvious facts to the contrary, from the point of evolution ageing should never have happened. This evolutionary contradiction has been debated and theorised on since the 1800s. It was only in 1953 with his hypothesis of antagonistic pleiotropy (AP) that George C. Williams gave us a rational explanation for how ageing can arise in a population through evolution. Williams proposed that natural selection enriches genes promoting reproductive success but consequently ignores their negative effects on longevity. Importantly, this is only true when those negative effects occur after the onset of reproduction. Essentially, if a gene mutation results in more offspring but shortens life that's fine. This is because there can be more descendants carrying on the parent's genes in a shorter time to compensate. Accordingly, over time, these pro-fitness, pro-ageing mutations are actively selected for and the ageing process becomes hard-wired into our DNA. While this theory has been proven mathematically and its implications demonstrated in the real world, actual evidence for genes behaving in such as fashion has been lacking.

This evidence has now arrived according to the co-lead author of the paper Jonathan Byrne, "The evolutionary theory of ageing just explains everything so nicely but it lacked real evidence that it was happening in nature. Evolution becomes blind to the effects of mutations that promote ageing as long as those effects only kick in after reproduction has started. Really, ageing is an evolutionary oversight." Jonathan continues "These AP genes haven't been found before because it's incredibly difficult to work with already old animals, we were the first to figure out how to do this on a large scale." He explains further "From a relatively small screen, we found a surprisingly large number of genes [30] that seem to operate in an antagonistic fashion." Previous studies had found genes that encourage ageing while still being essential for development, but these 30 genes represent some of the first found promoting ageing specifically only in old worms. "Considering we tested only 0.05% of all the genes in a worm this suggests there could be many more of these genes out there to find," says Jonathan.

The evidence for ageing driven by evolution was not the only surprise the paper had in store, according to Thomas Wilhelm, the other co-lead author on the paper. "What was most surprising was what processes those genes were involved in." Not content to provide just the missing evidence for a 60-year-old puzzle, Wilhelm and his colleagues went on to describe what a subset of these genes do in C. elegans and how they might be driving the ageing process. "This is where the results really get fascinating," says Dr Holger Richly, the principal investigator of the study. "We found a series of genes involved in regulating autophagy, which accelerate the ageing process." These results are surprising indeed, the process of autophagy is a critical recycling process in the cell, and is usually required to live a normal full lifetime. Autophagy is known to become slower with age and the authors of this paper show that it appears to completely deteriorate in older worms. They demonstrate that shutting down key genes in the initiation of the process allows the worms to live longer compared with leaving it running crippled. "This could force us to rethink our ideas about one of the most fundamental processes that exist in a cell," Holger explains. "Autophagy is nearly always thought of as beneficial even if it's barely working. We instead show that there are severe negative consequences when it breaks down and then you are better off bypassing it all together." "It's classic AP," he continues, "In young worms, autophagy is working properly and is essential to reach maturity but after reproduction, it starts to malfunction causing the worms to age."

In a final revelation, Richly and his team were able to track the source of the pro longevity signals to a specific tissue, namely the neurons. By inactivating autophagy in the neurons of old worms they were not only able to prolong the worms life but they increased the total health of the worms dramatically. "Imagine reaching the halfway point in your life and getting a drug that leaves you as fit and mobile as someone half your age who you then live longer than, that's what it's like for the worms," says Thomas Wilhelm. "We turn autophagy off only in one tissue and the whole animal gets a boost. The neurons are much healthier in the treated worms and we think this is what keeps the muscles and the rest of the body in good shape. The net result is a 50% extension of life."

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Evolution of 'true frogs' defies long-held expectations of science

Ranidae family are most diverse frog group in the world, found on all the world's continents except Antarctica.

Evolutionary biologists long have supposed that when species colonize new geographic regions they often develop new traits and adaptations to deal with their fresh surroundings. They branch from their ancestors and multiply in numbers of species.

Apparently, this isn't the story of "true frogs." The frog family scientists call Ranidae are found nearly everywhere in the world, and their family includes familiar amphibians like the American Bullfrog and the European common frog.

New research from the University of Kansas appearing in Royal Society Biology Letters shows, in contrast to expectations, "the rapid global range expansion of true frogs was not associated with increased net-diversification."

"First, we had to identify where these true frogs came from and when they started their dispersal all over the world," said lead author Chan Kin Onn, a doctoral student at KU's Biodiversity Institute. "We found a distinct pattern. The origin of these frogs was Indochina -- on the map today, it's most of mainland Asia, including Thailand, Vietnam, Cambodia and Burma. True frogs dispersed throughout every continent except Antarctica from there. That's not a new idea. But we found that a lot of this dispersal happened during a short period of time -- it was during the late Eocene, about 40 million years ago. That hadn't really been identified, until now."

Next, Chan and co-author Rafe Brown, curator-in-charge of the KU Biodiversity Institute's Herpetology Division, looked to see if this rapid dispersal of true frogs worldwide triggered a matching eruption of speciation.

"That was our expectation," Chan said. "We thought they'd take off into all this new habitat and resources, with no competition -- and boom, you'd have a lot of new species. But we found the exact opposite was true. In most of the groups, nothing happened. There was no increase in speciation. In one of the groups, diversification significantly slowed down. That was the reverse of what was expected."

To establish the actual timing of true frogs' diversification, Chan and Brown performed phylogenetic analysis of 402 genetic samples obtained from an online database called GenBank. These samples represented 292 of the known 380 true frog species in the world.

"We mined all of these sequences and combined them into a giant analysis of the whole family," Chain said. "It is to my knowledge the most comprehensive Ranidae phylogenetic analysis ever performed that included most of the representative species from the family."

Chan and Brown focused on four genes that would help to establish the family tree of true frogs.

"It's a genealogical pedigree of specimens, a family tree of species," Chan said. "Normally, you think of family tree as everyone in one family and how the various people are related. But this is more expanded where we look at how species are related to each other, so you can trace ancestry back in time."

After completing the phylogenetic analysis, the KU researchers used several frog fossils to "time calibrate" the history of the frogs' global dispersal.

"We use fossil frogs because we can accurately date the fossils," Chan said. "We know we found the fossil in a certain rock deposit, and we know with confidence how old the deposit is, so then we can estimate the age of the fossil."

After Chan and Brown deduced similarities between fossilized true frogs as reported by paleontologists and contemporary true frogs, they placed fossils into groups of closely related species, which scientists call genera.

"Using data from paleontological studies, we can loosely place a fossil where in the phylogeny it belongs and can put a time stamp on that point," Chan said. "That's where calibration happens, each fossil is sort of like an anchor point. You can imagine with a really big phylogeny, the more anchor points or calibration points the better your time estimate."

Through this process, the KU researchers concluded true frogs didn't become one of the most biodiverse frog families due to dispersing into new ranges, or due to filling a gap created by a catastrophic die-off (such as the Eocene-Oligocene Extinction Event that triggered widespread extinctions from marine invertebrates to mammals in Asia and Europe).

Rather, the rich diversity of species in the Ranidae family comes from millions of years' worth of continual evolution influenced by a host of different environs.

Read more at Science Daily

A one-of-a-kind star found to change over decades

AR Scorpii consists of a rapidly spinning, magnetized white dwarf star that mysteriously interacts with its companion star.

Astronomers studying the unique binary star system AR Scorpii have discovered the brightness of the system has changed over the past decade. The new evidence lends support to an existing theory of how the unusual star emits energy. AR Scorpii consists of a rapidly spinning, magnetized white dwarf star that mysteriously interacts with its companion star. The system was recently found to more than double in brightness on timescales of minutes and hours, but research recently published in The Astrophysical Journal Letters found variability on a timescale of decades.

Researchers at the University of Notre Dame analyzed data on the unique system from the Kepler Space Telescope's K2 mission taken in 2014 before the star was known to be unusual. The data was then compared with archival sky survey images going back to 2004 to look for long-term changes in the light curve of AR Scorpii. The binary's light curve is unique, in that it exhibits a spike in emission every two minutes as well as a major brightness variation over the approximately 3.5-hour orbital period of the two stars.

"One model of this system predicts long-term variations in the way the two stars interact. It was not known what the time scale of these changes might be -- whether 20 to 200 years. By looking at the K2 and archival data, we were able to show that in addition to hourly changes in the system, there are variations occurring over decades," said Peter Garnavich, professor and department chair of astrophysics and cosmology physics at Notre Dame.

A white dwarf is a very dense remnant of a star like the sun. When a solar-like star runs out of energy, gravity compresses its core to about the size of the Earth but with a mass 300,000 times higher. A teaspoon-sized piece of a white dwarf would weigh about 15 tons. The compression of the star can also amplify its magnetic field strength and its spin rate.

The unique system became famous in 2016 when researchers in England discovered that AR Scorpii, believed to be a mundane solitary star, was actually a rapidly varying binary. The system is remarkable as the white dwarf spins on its axis at an incredibly fast rate, causing flashes in luminosity every two minutes. The amplitude of the flashes varies over the 3.5-hour orbital period, something no other white dwarf binary system is known to do.

"We found that back 12 years ago, AR Scorpii's peak brightness came a bit later in its orbit than it does now," said Colin Littlefield, research associate working with Garnavich. "This does not solve the mystery, but it is another piece to the puzzle that is AR Scorpii."

The team at Notre Dame has been observing the system with the Sarah L. Krizmanich Telescope at the University's Jordan Hall of Science, and they plan to publish those results in an upcoming paper.

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Skin patch dissolves 'love handles' in mice

Microneedle patch.

Researchers have devised a medicated skin patch that can turn energy-storing white fat into energy-burning brown fat locally while raising the body's overall metabolism. The patch could be used to burn off pockets of unwanted fat such as "love handles" and treat metabolic disorders like obesity and diabetes, according to researchers at Columbia University Medical Center (CUMC) and the University of North Carolina.

The findings, from experiments in mice, were published online in ACS Nano.

Humans have two types of fat. White fat stores excess energy in large triglyceride droplets. Brown fat has smaller droplets and a high number of mitochondria that burn fat to produce heat. Newborns have a relative abundance of brown fat, which protects against exposure to cold temperatures. But by adulthood, most brown fat is lost.

For years, researchers have been searching for therapies that can transform an adult's white fat into brown fat -- a process named browning -- which can happen naturally when the body is exposed to cold temperatures -- as a treatment for obesity and diabetes.

"There are several clinically available drugs that promote browning, but all must be given as pills or injections," said study co-leader Li Qiang, PhD, assistant professor of pathology and cell biology at CUMC. "This exposes the whole body to the drugs, which can lead to side effects such as stomach upset, weight gain, and bone fractures. Our skin patch appears to alleviate these complications by delivering most drugs directly to fat tissue."

To apply the treatment, the drugs are first encased in nanoparticles, each roughly 250 nanometers (nm) in diameter -- too small to be seen by the naked eye. (In comparison, a human hair is about 100,000 nm wide.) The nanoparticles are then loaded into a centimeter-square skin patch containing dozens of microscopic needles. When applied to skin, the needles painlessly pierce the skin and gradually release the drug from nanoparticles into underlying tissue.

"The nanoparticles were designed to effectively hold the drug and then gradually collapse, releasing it into nearby tissue in a sustained way instead of spreading the drug throughout the body quickly," said patch designer and study co-leader Zhen Gu, PhD, associate professor of joint biomedical engineering at the University of North Carolina at Chapel Hill and North Carolina State University.

The new treatment approach was tested in obese mice by loading the nanoparticles with one of two compounds known to promote browning: rosiglitazone (Avandia) or beta-adrenergic receptor agonist (CL 316243) that works well in mice but not in humans. Each mouse was given two patches -- one loaded with drug-containing nanoparticles and another without drug -- that were placed on either side of the lower abdomen. New patches were applied every three days for a total of four weeks. Control mice were also given two empty patches.

Mice treated with either of the two drugs had a 20 percent reduction in fat on the treated side compared to the untreated side. They also had significantly lower fasting blood glucose levels than untreated mice.

Tests in normal, lean mice revealed that treatment with either of the two drugs increased the animals' oxygen consumption (a measure of overall metabolic activity) by about 20 percent compared to untreated controls.

Genetic analyses revealed that the treated side contained more genes associated with brown fat than on the untreated side, suggesting that the observed metabolic changes and fat reduction were due to an increase in browning in the treated mice.

"Many people will no doubt be excited to learn that we may be able to offer a noninvasive alternative to liposuction for reducing love handles," says Dr. Qiang. "What's much more important is that our patch may provide a safe and effective means of treating obesity and related metabolic disorders such as diabetes."

Read more at Science Daily

NASA’s Cassini Spacecraft Signs Off After Marathon of Scientific Discovery

A model of the Cassini spacecraft is seen at NASA's Jet Propulsion Laboratory (JPL) September 13, 2017 in Pasadena, California.

After 20 years in space, NASA's famed Cassini spacecraft made its final death plunge into Saturn on Friday, ending a storied mission that scientists say taught us nearly everything we know about Saturn today and transformed the way we think about life elsewhere in the solar system.

Cassini, an international project that cost $3.9 billion and included scientists from 27 nations, disintegrated as it dove into Saturn's atmosphere at a speed of 75,000 miles (120,700 kilometers) per hour.

"The signal from the spacecraft is gone," said Cassini program manager Earl Maize of NASA's Jet Propulsion Laboratory.

"I hope you are all as deeply proud of this amazing accomplishment," he told colleagues at mission control. "This has been an incredible mission, an incredible spacecraft and you are all an incredible team."

Cassini's final contact with Earth came at 7:55 am EDT (1155 GMT). Its descent into Saturn's atmosphere began about an hour and a half earlier, but the signal took that long to reach Earth because of the vast distance.

Cassini's plunge into the ringed gas giant — the furthest planet visible from Earth with the naked eye — came after the spacecraft ran out of rocket fuel after a journey of some 4.9 billion miles (7.9 billion kilometers).

Its well-planned demise was a way to prevent any damage to Saturn's ocean-bearing moons Titan and Enceladus, which scientists want to keep pristine for future exploration because they may contain some form of life.

"There are international treaties that require that we can't just leave a derelict spacecraft in orbit around a planet like Saturn, which has prebiotic moons," said Maize.

Cassini science team members await the final loss of signal from the Cassini spacecraft, indicating Cassini's destruction in Saturn's atmosphere and the end of Cassini's 20-year mission to gain a better understanding of the ringed planet and its icy moons, at the Jet Propulsion Laboratory in Pasadena, California on September 15, 2017.

Three other spacecraft have flown by Saturn — Pioneer 11 in 1979, followed by Voyager 1 and 2 in the 1980s.

But none have studied Saturn in such detail as Cassini, named after the French-Italian astronomer Giovanni Domenico Cassini, who discovered in the 17th century that Saturn had several moons and a gap between its rings.

"This is the final chapter of an amazing mission, but it's also a new beginning,” said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate. "Cassini's discovery of ocean worlds at Titan and Enceladus changed everything, shaking our views to the core about surprising places to search for potential life beyond Earth."

Discoveries

Cassini launched from Cape Canaveral, Florida in 1997, then spent seven years in transit followed by 13 years orbiting Saturn.

In that time, it discovered six more moons around Saturn, three-dimensional structures towering above Saturn's rings, and a giant storm that raged across the planet for nearly a year.

The 22-by-13-foot (6.7-by-4 meter) spacecraft is also credited with discovering icy geysers erupting from Enceladus, and eerie hydrocarbon lakes made of ethane and methane on Saturn's largest moon, Titan.

In 2005, the Cassini orbiter released a lander called Huygens on Titan, marking the first and only such landing in the outer solar system, on a celestial body beyond the asteroid belt.

Huygens was a joint project of the European Space Agency, Italian Space Agency, and NASA.

"The mission has changed the way we think of where life may have developed beyond our Earth," said Andrew Coates, head of the Planetary Science Group at Mullard Space Science Laboratory at University College London.

"As well as Mars, outer planet moons like Enceladus, Europa, and even Titan are now top contenders for life elsewhere," he added. "We've completely rewritten the textbooks about Saturn."

Linda Spilker, Cassini project scientist, likened Cassini's mission to a marathon.

"For 13 years we have been running a marathon of scientific discovery, and we are on the last lap," she said early Friday.

Eight of the spacecraft 12 scientific instruments were on, capturing data, in Cassini's last moments, before it disintegrates like a meteor, she said.

"We are flying more deeply into Saturn than we have ever flown before," she said. "Who knows how many Ph.D. theses might be in just those final seconds of data?"

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Pitch Black Exoplanet That Reflects No Light Spotted by Hubble Telescope

Artist’s impression of the pitch-black planet exoplanet WASP-12b in orbit around its sun.

A distant planet outside of our solar system is not only being eaten alive, but it also reflects almost no light.

New observations from the Hubble Space Telescope have revealed that the well-studied exoplanet WASP-12b — which is located about 1,400 light-years away from Earth — has an albedo, or reflectiveness, that is “darker than fresh asphalt,” according to principal investigator Taylor Bell, an astronomy master’s student at McGill University in Canada.

WASP-12b was discovered in 2008 and remains a subject of intrigue for astronomers. The planet, called a “hot Jupiter” because it is huge and very close to its star, has an egg shape due to the star’s gravity. The star also tugs on the planet’s atmosphere, stripping away the gas giant’s outer layers. Astronomers made the new observations to learn more about the composition of the atmosphere.

“There are other hot Jupiters that have been found to be remarkably black, but they are much cooler than WASP-12b,” said Bell in a statement on the European Space Agency’s Hubble Space Telescope website. “For those planets, it is suggested that things like clouds and alkali metals [such as sodium or potassium] are the reason for the absorption of light, but those don’t work for WASP-12b because it is so incredibly hot.”

Specifically, the team found that WASP-12b is made up mostly of helium and atomic hydrogen. On the day side of WASP-12b, it’s too hot to form clouds and alkali metals become ionized, meaning they gain or lose electrons. The heat also breaks apart hydrogen molecules into atomic hydrogen, a common element in low-mass stars. It’s the hydrogen, in combination with WASP-12b’s temperature, that makes the albedo of the exoplanet so low.

WASP-12b’s albedo is only 0.064. By comparison, Earth’s albedo is about 0.37 and Enceladus – an icy Saturn moon that has the highest reflectivity of the solar system – has an albedo of 1.4.

The researchers measured WASP-12b’s albedo during an eclipse, when the planet went behind its host star. Scientists looked at the amount of light being reflected using Hubble’s Space Telescope Imaging Spectrograph and compared their observations of the planet to previous atmospheric models. What they saw didn’t match either of the proposed models.

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Mammoth Tooth Discovery Suggests Ancient Beast Was Feeding Just West of Austin

Mammoth remains at the Waco Mammoth National Monument.

CALGARY, Alberta — About 67,000 years ago, a gigantic mammoth chowed down on enormous mouthfuls of grass in Texas, just west of where modern-day Austin is located, according to new research.

The finding is surprising, given that the beast's remains were discovered in Waco, Texas, more than 120 miles (200 kilometers) away from the Columbian mammoth's (Mammuthus columbi) ancient picnic spot near Austin, the researchers said. 

"They really weren't in the Waco area until right before they died, which is a little unexpected," the study's lead researcher, Don Esker, a doctoral candidate in the Department of Geosciences at Baylor University in Waco, told Live Science. "Two hundred kilometers is within the largest distance that we've known Columbian mammoths to travel, but only just."

Esker and his colleagues made this discovery by studying the isotopes (an isotope is a variation of an element that has a different number of neutrons in its nucleus) in the mammoth's teeth. So far, Esker has studied just one tooth, but he has plans to examine more teeth from different mammoths in the coming months.

Esker could have a lot of work in front of him. There are remains from at least 23 mammoths dating to the late Pleistocene in Waco. The prehistoric graveyard was found in 1978 by two local youngsters, Paul Barron and Eddie Bufkin, who were searching for fossils and arrowheads when they discovered the fossilized mammoth bones. In 2015, President Barack Obama issued a presidential proclamation, with bipartisan support, that made the site a national monument, according to the National Park Service.

This map shows the strontium isotope landscape around Texas. The only area that matched the strontium ratios in the mammoth’s tooth was the purple area, which sits just west of Austin.

It's likely, but not certain, that these fossils are from the same mammoth nursey herd, Esker said. His goal is to confirm whether these mammoths traveled together as a social group, and to learn where they traveled and what they ate, he said.

If his research reveals these mammoths gulped down the same kind of water and gobbled up the same types of food, then it's likely they did travel as a herd, he told Live Science here at the 2017 Society of Vertebrate Paleontology meeting.

Mammoth menu

To get started, Esker analyzed the carbon, oxygen and strontium ratios in a single mammoth tooth, which helped him reconstruct "an itinerary and menu for the mammoth over the last six years of its life," he said.

When mammoths dined on vegetation, the plants' nutrients eventually ended up in their teeth. This information can reveal what types of plants the mammoths ate, because the way plants photosynthesize energy from the sun governs what type of carbon isotopes they produce: Carbon 4 (C4) indicates that the beasts ate grasses and sedges, and carbon 3 (C3) shows that they ate most other vegetation, including honey locust, Osage orange and mesquite.

Researchers took 27 samples from this mammoth tooth so they could test the isotopes within it.

"The carbon told us that the mammoth in question ate 65 percent to 75 percent warm season C4 grasses year-round," Esker said. This supports evidence from mammoth fossilized poop, or coprolites, that also revealed that Columbian mammoths ate plants containing C4.

Meanwhile, the oxygen isotopes in the mammoth's tooth showed that conditions "may have been a good deal more arid than [they are] today," Esker said.

Finally, the strontium isotopes revealed that the mammoths "spent a good deal of time eating grass growing on granite-derived soil," Esker said. The only place Esker could find with this type of soil was west of Austin, he said.

In addition to studying mammoth teeth, Esker and his colleagues plan to analyze chompers from a horse, camel and pronghorn that also perished at the Waco site. The results will show whether these animals' ranges overlapped with the mammoths' stomping grounds, Esker said.

Read more at Seeker

Cassini Prepares to Crash Into Saturn as NASA Reflects on Mission's Discoveries

Saturn and its rings.

After 14 years of exploration, the Cassini spacecraft is preparing to write its final chapter on the Saturn system.

No other spacecraft in history has come to know a single planetary system as intimately as Cassini knows Saturn: Cassini is the first spacecraft to visit Saturn up close since the Voyager probes flew by in 1980 and 1981, and the mission has given scientists their best-ever views of the gas giant.

The probe has spent more than a decade observing Saturn, studying storms in its cloud tops, learning about its strange, striped atmosphere, probing its cloaked interior and zipping through its more than 60 moons and a ring system stretching more than eight times the planet's radius.

"The mission has exceeded all of our expectations, done better than we could have ever dreamed," Curt Niebur, Cassini's program scientist from NASA headquarters in Houston, said during a press teleconference in August. "The Saturn system is absolutely chock-full of amazing worlds of all sizes, and Cassini has been exploring them for the past 13 years.

"Since our arrival in 2004, we've watched the seasons change on Saturn, which is just an incredible opportunity, considering a year on Saturn lasts 29 Earth years," he added. "We've watched the particles and the rings around Saturn collide and glide during their gravitational dance, and we've confirmed things that we suspected might exist in the Saturn system, but even more pleasantly, we've been shocked by things that we never predicted we would find."

Cassini's scientists have watched a Saturn storm erupt and run over its own tail after circling the entire planet. They've probed the mysteries of the Earth-size, hexagonal jet stream on the planet's pole that persists in all seasons, but changes color over time. Researchers have sent a probe down to Saturn's largest moon, Titan, to see the lakes, seas and rivers of methane on its surface, and have flown Cassini through the geyser jets of the tiny moon Enceladus to probe its newfound ice-covered ocean.

"These two new worlds, Titan and Enceladus, which were so completely revealed to us by Cassini, have changed the idea that ocean worlds like Earth and [Jupiter's moon] Europa are rare in the universe," Niebur said. "And this in turn is changing our views about finding [habitable worlds] and about how prevalent and common habitable environments and even life beyond Earth might truly be."

The mission has continually adapted to the mysteries it uncovered in Saturn's system. The probe used flybys of Titan to adjust its orbit and perform 162 targeted flybys of Saturn's many moons, including 127 of Titan itself.

Saturn's moons Enceladus and Tethys line up above Saturn's rings in this 2015 photo from the Cassini spacecraft, which has been exploring Saturn's system since 2004.

"Cassini's had a long-distance, you might say, long-term relationship with Titan," Earl Maize, Cassini's project manager at NASA's Jet Propulsion Laboratory in California, said during the teleconference. "[During] each of these flybys, Titan has shared some of its secrets with us, and at the same time shaped Cassini's trajectory."

Via an international collaboration, Cassini brought Europe's Huygens lander to the Saturn system and dropped it down on Titan, giving Earthlings a stunning view of the moon's liquid oceans and complex organic atmosphere. Maize said that moment is his pick for the most amazing part of the Cassini mission.

"The collaboration… between three space agencies and all these thousands of people on the ground… [to] put a probe onto Titan, capture signal on the way down, land it softly on the surface and play those images back — I still give myself goose bumps just seeing that first image," Maize said. The Cassini mission is a cooperative project between NASA, the European Space Agency (ESA) and the Italian Space Agency.

For Linda Spilker, a Cassini project scientist at JPL, the probe's investigation of the tiny moon Enceladus was the most exciting part of the mission.

"To actually see this plume of water vapor and waterized particles coming out of the south pole of a moon that's only 300 miles [480 kilometers] across was absolutely astonishing," Spilker said at the teleconference. "And then to take instruments built for other purposes and turn them toward sampling and flying through the plumes and actually measuring the constituents — finding a salty global ocean containing organics, the possibility of hydrothermal ventsand just revealing a world that we thought was completely frozen solid when we first got to Saturn."

"Enceladus has no business existing," Niebur added, "and yet there it is — practically screaming at us, 'Look at me! I completely invalidate all of your assumptions about the solar system!'"

To protect those Enceladus and Titan from contamination with Earth life, Cassini is going to dive down into Saturn's atmosphere before the probe runs out of fuel, which could have left it drifting on a collision course with the planet's moons. Although the Huygens mission met planetary-protection requirements back in 2005, when it landed on Titan, scientists' new information about that moon's potential habitability has made researchers keen to protect it from further exposure, Cassini research scientists have said. Saturn's "Grand Finale" dive is primarily aimed to protect Enceladus, which has a higher planetary-protection standard — Titan is just a bonus, the scientists said.

For the final dive, researchers will turn their focus back to the planet itself and its rings for a dramatic, fact-finding atmospheric crash.

"The mission has been insanely, wildly, beautifully successful," Niebur said. "But Cassini will not go quietly."

The spacecraft's Grand Finale orbits have brought it closer to the gas giant than any spacecraft has traveled, traversing the gap between the planet and its rings and diving into the unknown to learn as much as possible about the planet.

"Some of our key science goals during the Grand Finale are trying to understand Saturn from the inside out, to figure out the length of a Saturn day and to determine the mass of the rings and the composition of Saturn's atmosphere," Spilker said. "Our understanding of this fascinating new data is still evolving for me and the science team. There are so many puzzles at Saturn.

"Scientists love mysteries, and the Grand Finale is providing mysteries for everyone," she added. And surely that will continue with its final dive, she said.

At the briefing, researchers described how the probe would eventually stop sending photos, but would be sending back data gathered with its instruments right up until the end. The probe's first protective blankets will burn off first as it pierced the planet's upper atmosphere — "just like you see when you re-enter the atmosphere on Earth," Julie Webster, a Cassini operations manager at JPL, said at the conference — and then the craft will reach the aluminum melting point within about 20 seconds. The probe's iridium will be the last to melt, occurring about 30 seconds after the aluminum; everything will be melted away within a minute.

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Objects Destabilized by Jupiter or Saturn May Have First Brought Water to Earth

A lingering question among researchers is: How did water first appear on Earth?

Earth's neighborhood was quite dry during to the early moments of the universe, according to some studies, which means that somehow, water was brought from other parts of the solar system, such as the outer areas of the asteroid belt lying between Mars and Jupiter. Other studies have found that water on Earth matches the water found in the asteroid belt. But debate remains about how that water was delivered to Earth.

A new paper published in the journal Icarus suggests Earth's water indeed came from small bodies called planetesimals, which formed in the asteroid belt and the regions around Jupiter and Saturn that lie beyond the belt. The findings were based on computer simulations of the early universe.

"In simple terms, the growing giant planets are like toddlers throwing their food on the walls and the floor," Sean Raymond, lead author of the study and an astronomer at the University of Bourdeaux, told Seeker.

As planets formed during the early moments of our solar system, Raymond explained, the gas giants destabilized the orbits of nearby planetesimals, stretching their paths from circles to ellipses, which eventually pushes them across the orbits of Jupiter or Saturn.

"The planetesimals rarely collide with the giant planets, but they do come pretty close and get huge gravitational kicks,” Raymond said. “They are flung all over the solar system, and a fraction are deposited on new, stable orbits in the asteroid belt, preferentially in the outer [region of the] belt. Some of them are kicked inward past the asteroid belt to where the rocky planets are growing, seeding them with water."

A model of how our solar system could have looked early in its formation. At left is the young sun (a protosun), with particles of gas (the nebula) and chunks of rock (the planetesimals) nearby. This zone is approximately where the inner solar system exists today. Most of the water in the solar system lay beyond the "frost line."

Raymond acknowledged that estimates of the exact amount of water delivered to Earth vary, depending on variations in the structure of the disk of planet-building material surrounding the sun. He said, though, the process of water-rich planetesimals migrating near Earth is "unavoidable."

Raymond said there is ongoing work to determine why the Earth's solar system looks so different from other solar systems. For example, elsewhere large gas giants orbit very close to their parent star. Imagine Jupiter or Saturn right next door to the sun. And other systems host "super-Earths," or planets that are between the size of Earth and Neptune. These findings suggest that giant planets may migrate positions over time and affect the orbits of other planets, perhaps kicking out Earth-sized planets from a solar system altogether, in some cases.

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Enhanced NASA Images Show Potential for Buried Ice Near the Martian Equator

Recurring slope lineae in Mars's Juventae Chasma

NASA made headlines around the world back in 2015 when it discovered evidence of briny water flowing on the surface of Mars. The agency detected hydrated salts flowing within recurring slope lineae, or RSLs, which are streaks that appear on the sides of craters. RSLs are more prominent when the weather is warm, implying that sunlight might be enabling the features to flow in the warmer weather.

It remains unclear whether or not RSLs are salts. Some studies suggest the water comes from trace amounts available in the Red Planet's atmosphere, while others say the streaks appear to be dry sand, especially because the streaks are straight, not wavy like one would expect from water. But if RSLs come from water, what is the source, and how substantial is the supply? And is it enough to sustain life?

Researchers writing in the journal Icarus analyzed observations from NASA's Mars Odyssey spacecraft to learn more about RSLs. The images, sharpened by half from their original resolution of about 550 kilometers (340 miles), showed an abundance of hydrogen, which is an indication of water.

"In bringing the lower-resolution compositional data into sharper focus, we saw unexpectedly high amounts of hydrogen — a potential sign of buried water ice or very hydrated salts — around sections of the Martian equator," Jack Wilson, principal author and a planetary scientist at the Johns Hopkins Applied Physics Laboratory, told Seeker in an email.

He acknowledged that we can't know for sure how much water is inside of an RSL unless we sent a rover to excavate. That's certainly possible, but if there is life within an RSL, a rover could contaminate the area with microbes from Earth.

What Wilson's study reveals is the presence of the same amount of water in the regions with RSLs as those without the features. This means that RSLs can't be fed from water in the near subsurface, at least according to the data he gathered. A limitation, however, is the resolution of the neutron data is a few hundred kilometers, and RSLs are only 100 meters in length at the most. This means that something could be going on that Mars Odyssey could not see, perhaps greater amounts of water available near the RSLs than what the spacecraft spotted.

The study raises interesting questions about what feeds the RSLs, such as an underground source. Wilson said the most interesting part of the study was seeing so much water is contained in the subsurface near the equator.

"Where this water came from and why it is still present near the surface are interesting questions," he said.

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Earthquake faults may have played key role in shaping the culture of ancient Greece

The Ancient Greeks may have built sacred or treasured sites deliberately on land previously affected by earthquake activity, according to a new study by the University of Plymouth.

Professor of Geoscience Communication Iain Stewart MBE, Director of the University's Sustainable Earth Institute, has presented several BBC documentaries about the power of earthquakes in shaping landscapes and communities.

Now he believes fault lines created by seismic activity in the Aegean region may have caused areas to be afforded special cultural status and, as such, led to them becoming sites of much celebrated temples and great cities.

Scientists have previously suggested Delphi, a mountainside complex once home to a legendary oracle, gained its position in Classical Greek society largely as a result of a sacred spring and intoxicating gases which emanated from a fault line caused by an earthquake.

But Professor Stewart believes Delphi may not be alone in this regard, and that other cities including Mycenae, Ephesus, Cnidus and Hierapolis may have been constructed specifically because of the presence of fault lines.

Professor Stewart said: "Earthquake faulting is endemic to the Aegean world, and for more than 30 years, I have been fascinated by the role earthquakes played in shaping its landscape. But I have always thought it more than a coincidence that many important sites are located directly on top of fault lines created by seismic activity. The Ancient Greeks placed great value on hot springs unlocked by earthquakes, but perhaps the building of temples and cities close to these sites was more systematic than has previously been thought."

In the study, published in Proceedings of the Geologists' Association, Professor Stewart says a correspondence of active faults and ancient cities in parts of Greece and western Turkey might not seem unduly surprising given the Aegean region is riddled with seismic faults and littered with ruined settlements.

But, he adds, many seismic fault traces in the region do not simply disrupt the fabric of buildings and streets, but run straight through the heart of the ancient settlements' most sacred structures.

There are prominent examples to support the theory, such as in Delphi itself where a sanctuary was destroyed by an earthquake in 373BC only for its temple to be rebuilt directly on the same fault line.

There are also many tales of individuals who attained oracular status by descending into the underworld, with some commentators arguing that such cave systems or grottoes caused by seismic activity may have formed the backdrop for these stories.

Read more at Science Daily

Cold region 'tipping point' now inevitable

This photo shows intense soil frost churning in Kilpisjärvi, northwestern most Finland, at 800 metres above sea level.

The decline of cold regions called periglacial zones is now inevitable due to climate change, researchers say.

Periglacial zones, where there is often a layer of frozen ground known as permafrost, make up about a quarter of Earth's land surface and are mostly found in the far north and south, and at high altitudes.

Scientists from the universities of Exeter and Helsinki and the Finnish Meteorological Institute examined natural processes caused by frost and snow which take place in these zones.

Their findings suggest that -- even with optimistic estimates of future carbon emissions -- areas covered by periglacial zones will reduce dramatically by 2050, and they will "almost disappear" by 2100.

This would have a major impact on landscapes and biodiversity, and could trigger climate "feedbacks" -- processes that can amplify or diminish the effects of climate change.

"The results suggest that profound changes can be expected in current periglacial zones regardless of climate change mitigation policies," said Dr Juha Aalto, of the University of Helsinki and the Finnish Meteorological Institute.

"Unfortunately, it seems that many of the frost-driven processes we studied are already at the margin of the climate in which they can exist."

The scientists studied four processes which take place in periglacial zones, including snow accumulation sites and "frost churning" -- which refers to mixing of materials caused by freezing and thawing.

"Our results forecast a future tipping point in the operation of these processes, and predict fundamental changes in ground conditions and related atmospheric feedbacks," Dr Aalto added.

Dr Stephan Harrison, of the University of Exeter's Penryn Campus in Cornwall, said: "The project used very high-resolution climate and land surface models to demonstrate that geological processes and ecosystems in high latitudes (the far north and south) will be fundamentally altered by climate change during this century."

Even based on the optimistic RCP2.6 estimate for future carbon emissions, the researchers predict a 72% reduction in the current periglacial zone in the area of northern Europe they studied.

By 2100, periglacial zones in will only exist in high mountain regions, they say.

Professor Miska Luoto, of the University of Helsinki, said: "The anticipated changes in land surface processes can feedback to the regional climate system via alterations in carbon cycle and ground surface reflectance (light reflected by snow and ice) caused by the increase of shrub vegetation to alpine tundra.

Read more at Science Dialy

Coffee and bees: New model of climate change effects

Areas in Latin America suitable for growing coffee face predicted declines of 73-88 percent by 2050. However, diversity in bee species may save the day, even if many species in cool highland regions are lost as the climate warms. The research, co-authored by David Roubik, senior scientist at the Smithsonian Tropical Research Institute, will be published in an early online Proceedings of the National Academy of Sciences edition between Sept. 11-15.

"For my money, we do a far superior job of predicting the future when we consider both plants and animals (or in this case the bees) and their biology," Roubik said. "Traditional models don't build in the ability of organisms to change. They're based on the world as we know it now, not on the way it could be as people and other organisms adapt."

A research team modeled impacts for Latin America, the largest coffee-growing region under several global-warming scenarios -- considering both the plants and the bees. The team consisted of experts from the Smithsonian in Panama; the International Center for Tropical Agriculture in Vietnam; the Tropical Agricultural Research and Higher Education Center in Costa Rica; Conservation International and the University of Vermont in the U.S.; CIRAD in France; and CIFOR in Peru.

Despite predicted declines in total bee species, in all scenarios at least five bee species were left in future coffee-suitable areas; in about half of the areas, 10 bee species were left.

For land no longer suitable for coffee production, the team recommended management strategies to help farmers switch to other crops or production systems. In areas where bee diversity is expected to decrease, but coffee can still be grown, adaptation strategies may include increasing bee habitat and maintaining native bees. Many coffee types prefer to grow in the shade of tall trees. Choosing tree species that favor bees is a win-win strategy, according to the authors.

Roubik's favorite example of a potentially huge environmental change that did not play out as predicted is the case of Africanized honey bees, which were accidentally released in Brazil in 1957. Roubik's studies in Panama of coffee pollination taking native rainforest bees into consideration began in the 1970s as the aggressive non-native Africanized honey bees swarmed north through Latin America. Doomsayers predicted the worst: that the killer bees would disrupt the delicate balance between tropical forest species and their native pollinators. Roubik discovered the opposite to be true. In lowland tropical forests in Mexico, plants pollinated by very busy Africanized bees ended up producing more flowers, thus making more pollen and nectar available to native bees.

"Africanized honey bees in the Western Hemisphere both regulate their nest temperature and their own body temperature using water," Roubik said. "When the climate is hotter -- unless it's too dry -- they're better adapted to endure climate change and pollinate coffee -- an African plant."

Read more at Science Daily

This Flesh-Eating Parasite Might Soon Be Thwarted by a New Vaccine

An Afghan mother holds her son who has Leishmaniasis as they wait for treatment at the Health Net Clinic October 23, 2002 in Kabul, Afghanistan.

US and Brazilian researchers say they’ve taken a big step toward a vaccine that could stop a flesh-eating parasite that’s moving northward due to climate change.

Leishmaniasis is a disfiguring condition that causes skin ulcers and boils and sometimes launches potentially life-threatening attacks on the digestive system. It’s caused by a single-celled pest that’s passed to humans by the bite of the sand fly, sickening as many as 1 million people a year and killing up to 30,000, according to the World Health Organization.

But scientists may have found a way to disrupt the Leishmania parasite using a bioengineered, virus-like particle and a compound that unmasks the parasite and opens it up to attack from the body’s own defenses.

“It can help the whole immune system to target this parasite,” said Alexandre Marques, a microbiologist who studies parasites at Brazil’s Federal University of Minas Gerais. “It won’t allow this parasite to reproduce inside your cells or reach different organs to cause different symptoms.”

In study results published Tuesday, Marques and Georgia Tech chemist MG Finn found their potential vaccine effectively eliminated the parasite in mice whose immune systems had been genetically modified to mimic human defenses. It targets a carbohydrate found on the parasite that helps the organism evade detection and hole up inside the body.

The process uses an artificially generated, virus-like particle developed at Georgia Tech to boost the body’s production of antibodies. Once activated, the antibodies seek out and destroy the parasite. All of the mice who received the vaccine had extremely low or non-detectable levels of Leishmania afterward, Marques said.

Using a virus-like particle allows scientists to trick the immune system into reacting, Finn said. It’s safer than other vaccines that use a weakened or inert form of a disease, but are not always as effective, he said.

Of 15 mice that received vaccinations, none showed any signs of the parasite. Autopsies on six of those mice confirmed they were Leishmania-free, Marques said.

Most of the time, leishmaniasis causes skin lesions that leave permanent scars — but it can spread to the liver and spleen, causing fever and anemia. The more serious form is called visceral leishmaniasis, often known as kala azar. There is no vaccine, and treatments can involve side effects ranging from nausea to pancreatic and heart conditions.

Leishmaniasis is already in about 90 countries Southern Europe, Central America, and Mexico. A few cases of cutaneous leishmaniasis — the kind that causes skin sores — have turned up in Texas and Oklahoma, according to the US Centers for Disease Control and Prevention.

But the sand flies that carry the parasite can thrive in rainy environments with temperatures above 30 degrees Celsius (86 degrees Fahrenheit), Marques said — conditions that are expected to become more common in North America in an era of warming temperatures.

“This facilitates the conditions for the sand fly to survive because they have the rain, temperature, and humidity that are perfect for them to survive, reproduce, and pass the parasite to new hosts,” he said.

Read more at Seeker

Does the organic material of comets predate our solar system?

The nucleus of comet 67P Churyumov-Gerasimenko (“Chury") as seen by the European Rosetta space probe.

The ESA's Rosetta mission, which ended in September 2016, found that organic matter made up 40% (by mass) of the nucleus of comet 67P Churyumov-Gerasimenko, a.k.a. Chury. Organic compounds, combining carbon, hydrogen, nitrogen, and oxygen, are building blocks of life on Earth. Yet, according to Jean-Loup Bertaux and Rosine Lallement -- from the Laboratoire Atmosphères, Milieux, Observations Spatiales (CNRS / UPMC / Université de Versailles Saint-Quentin-en-Yvelines) and the Galaxies, Étoiles, Physique et Instrumentation department of the Paris Observatory (Observatoire de Paris / CNRS / Université Paris Diderot), respectively -- these organic molecules were produced in interstellar space, well before the formation of the Solar System. Bertaux and Lallement further assert that astronomers are already familiar with much of this matter.

For 70 years, scientists have known that analysis of stellar spectra indicates unknown absorptions, throughout interstellar space, at specific wavelengths called the diffuse interstellar bands (DIBs). DIBs are attributed to complex organic molecules that US astrophysicist Theodore Snow believes may constitute the largest known reservoir of organic matter in the Universe. This interstellar organic material is usually found in the same proportions. However, very dense clouds of matter like presolar nebulae are exceptions. In the middle of these nebulae, where matter is even denser, DIB absorptions plateau or even drop. This is because the organic molecules responsible for DIBs clump together there. The clumped matter absorbs less radiation than when it floated freely in space.

Such primitive nebulae end up contracting to form a solar system like our own, with planets . . . and comets. The Rosetta mission taught us that comet nuclei form by gentle accretion of grains progressively greater in size. First, small particles stick together into larger grains. These in turn combine into larger chunks, and so on, until they form a comet nucleus a few kilometers wide.

Thus, the organic molecules that formerly populated the primitive nebulae -- and that are responsible for DIBs -- were probably not destroyed, but instead incorporated into the grains making up cometary nuclei. And there they have remained for 4.6 billion years. A sample-return mission would allow laboratory analysis of cometary organic material and finally reveal the identity of the mysterious interstellar matter underlying observed absorption lines in stellar spectra.

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When ancient fossil DNA isn't available, ancient glycans may help trace human evolution

Partial upper jaw of Australopithecus anamensis, a primitive hominin, recovered from the bone bed excavated at the Allia Bay site.

Ancient DNA recovered from fossils is a valuable tool to study evolution and anthropology. Yet ancient fossil DNA from earlier geological ages has not been found yet in any part of Africa, where it's destroyed by extreme heat and humidity. In a potential first step at overcoming this hurdle, researchers at University of California San Diego School of Medicine and Turkana Basin Institute in Kenya have discovered a new kind of glycan -- a type of sugar chain -- that survives even in a 4 million-year-old animal fossil from Kenya, under conditions where ancient DNA does not.

While ancient fossils from hominins (human ancestors and extinct relatives) are not yet available for glycan analysis, this proof-of-concept study, published September 11 in Proceedings of the National Academy of Sciences, may set the stage for unprecedented explorations of human origins and diet.

"In recent decades, many new hominin fossils were discovered and considered to be the ancestors of humans," said Ajit Varki, MD, Distinguished Professor of Medicine and Cellular and Molecular Medicine at UC San Diego School of Medicine. "But it's not possible that all gave rise to modern humans -- it's more likely that there were many human-like species over time, only one from which we descended. This new type of glycan we found may give us a better way to investigate which lineage is ours, as well as answer many other questions about our evolution, and our propensity to consume red meat."

Glycans are complex sugar chains on the surfaces of all cells. They mediate interaction between cells and the environment, and often serve as docking sites for pathogens. For millions of years, the common ancestors of humans and other apes shared a particular glycan known as Neu5Gc. Then, for reasons possibly linked to a malarial parasite that exploited Neu5Gc as a means to establish infection, a mutation that probably occurred between 2 and 3 million years ago inactivated the human gene encoding the enzyme that makes the molecule. The loss of Neu5Gc amounted to a radical molecular makeover of human ancestral cell surfaces and might have created a fertility barrier that expedited the divergence of the lineage leading to humans.

Today, chimpanzees and most other mammals still produce Neu5Gc. In contrast, only trace amounts can be detected in human blood and tissue -- not because we make Neu5Gc, but, according to a previous study by Varki's team, because we accumulate the glycan when eating Neu5Gc rich red meat. Humans mount an immune response to this non-native Neu5Gc, possibly aggravating diseases such as cancer.

In their latest study, Varki and team found that, as part of its natural breakdown, a signature part of Neu5Gc is also incorporated into chondroitin sulfate (CS), an abundant component in bone. They detected this newly discovered molecule, called Gc-CS, in a variety of mammalian samples, including easily detectable amounts in chimpanzee bones and mouse tissues.

Like Neu5Gc, they found that human cells and serum have only trace amounts of Gc-CS -- again, likely from red meat consumption. The researchers backed up that assumption with the finding that mice engineered to lack Neu5Gc and Gc-Cs (similar to humans) had detectable Gc-CS only when fed Neu5Gc-containing chow.

Curious to see how stable and long-lasting Gc-CS might be, Varki bought a relatively inexpensive 50,000-year-old cave bear fossil at a public fossil show and took it back to the lab. Despite its age, the fossil indeed contained Gc-CS.

That's when Varki turned to a long-time collaborator -- paleoanthropologist and famed fossil hunter Meave Leakey, PhD, of Turkana Basin Institute of Kenya and Stony Brook University. Knowing that researchers need to make a very strong case before they are given precious ancient hominin fossil samples, even for DNA analysis, Leakey recommended that the researchers first prove their method by detecting Gc-CS in even older animal fossils. To that end, with the permission of the National Museums of Kenya, she gave them a fragment of a 4-million-year-old fossil from a buffalo-like animal recovered in the excavation of a bone bed at Allia Bay, in the Turkana Basin of northern Kenya. Hominin fossils were also recovered from the same horizon in this bone bed.

Varki and team were still able to recover Gc-CS in these much older fossils. If they eventually find Gc-Cs in ancient hominin fossils as well, the researchers say it could open up all kinds of interesting possibilities.

"Once we've refined our technique to the point that we need smaller sample amounts and are able to obtain ancient hominin fossils from Africa, we may eventually be able to classify them into two groups -- those that have Gc-CS and those that do not. Those that lack the molecule would mostly likely belong to the lineage that led to modern humans," said Varki, who is also adjunct professor at the Salk Institute for Biological Studies and co-director of the UC San Diego/Salk Center for Academic Research and Training in Anthropogeny (CARTA).

In a parallel line of inquiry, Varki hopes Gc-CS detection will also reveal the point in evolution when humans began consuming large amounts of red meat.

"It's possible we'll one day find three groups of hominin fossils -- those with Gc-CS before the human lineage branched off, those without Gc-CS in our direct lineage, and then more recent fossils in which trace amounts of Gc-CS began to reappear when our ancestors began eating red meat," Varki said. "Or maybe our ancestors lost Gc-CS more gradually, or only after we began eating red meat. It will be interesting to see, and we can begin asking these questions now that we know we can reliably find Gc-CS in ancient fossils in Africa."

Read more at Science Daily

Why your ancestors would have aced the long jump

This tiny ankle bone belonged to one of the earliest members of the primate family tree. The 52-million-year-old fossil suggests that the first primates were expert leapers. Discovered more than 30 years ago by paleontologist Marc Godinot, the fossil is now housed at the Muséum National d'Histoire Naturelle in Paris.

A 52-million-year-old ankle fossil suggests our prehuman ancestors were high-flying acrobats.

These first primates spent most of their time in the trees rather than on the ground, but just how nimble they were as they moved around in the treetops has been a topic of dispute.

For years, scientists thought the ancestors of today's humans, monkeys, lemurs and apes were relatively slow and deliberate animals, using their grasping hands and feet to creep along small twigs and branches to stalk insects or find flowers and fruits.

But a fossil study published in the October 2017 issue of the Journal of Human Evolution suggests the first primates were masters at leaping through the trees.

Paleontologists working in a quarry in southeastern France uncovered the quarter-inch-long bone, the lower part of the ankle joint.

The fossil matched up best with a chipmunk-sized creature called Donrussellia provincialis.

Previously only known from jaws and teeth, Donrussellia is thought be one of the earliest members of the primate family tree, on the branch leading to lemurs, lorises and bush babies.

Duke University assistant professor Doug Boyer and colleagues studied scans of Donrussellia's ankle and compared it to other animals, using computer algorithms to analyze the 3-D digital shape of each tiny bone.

They were surprised to find that Donrussellia's ankle was not like those of other primates, but was more similar to those of treeshrews and other nonprimate species.

The team's analyses also suggest the animal didn't just clamber or scurry along small branches. Instead, it may have been able to bound between trunks and branches, using its grasping feet to stick the landing.

The researchers say that -- contrary to what many scientists thought -- the first primates may have evolved their acrobatic leaping skills first, while anatomical changes that allowed them to cling to slender branch tips and creep from tree to tree came later.

Read more at Science Daily

Peculiar Waves in Saturn's Rings Spotted by NASA's Cassini Probe

Wave-like images captured by Cassini as it orbits Saturn.

NASA's Cassini spacecraft has captured a spectacular photo of a perplexing wave structure in one of Saturn's rings as the probe heads into its final days at the gas giant.

The rings of Saturn are embedded with billions of water-ice particles ranging in size from grains of sand to monstrous chunks. Saturn's rings also feature waves that propagate outward in spiral patterns.

The new image from Cassini captures an up-close view of a spiral density wave visible in Saturn's B ring. The wave structure is a buildup of material that has formed from the gravitational pull of Saturn's moons, NASA officials said.

The density wave visible in Saturn's B ring originates 59,796 miles (96,233 kilometers) from the planet, where the "ring particles orbit Saturn twice for every time the moon Janus orbits once, creating an orbital resonance," according to a statement from NASA.

In the new image, the wave structure — aptly named the Janus 2:1 spiral density wave — appears to ricochet outward, away from Saturn and toward the upper-left corner of the photo, creating hundreds of bright wave crests.

The density wave is generated by the gravitational pull of Saturn's moon Janus. However, Janus and one of Saturn's other moons, Epimetheus, share practically the same orbit and swap places every four years, creating a new crest in the wave, according to the statement.

As a result, the distance between any pair of crests corresponds to four years' worth of wave oscillations. This pattern represents the orbital history of Janus and Epimetheus, much like the rings of a tree reveal information about its growth.

Based on this idea, the crests of the wave at the very upper left of the new Cassini image correspond to the positions of Janus and Epimetheus during the Saturn flybys of NASA's twin Voyager probes in 1980 and 1981, according to the statement.

Read more at Seeker

Children Exposed to Toxic 9/11 Dust Show Signs of Heart Disease as Young Adults

Dust swirls around south Manhattan after a tower of the World Trade Center collapses September 11, 2001 in New York City after two airplanes slammed into the twin towers in a terrorist attack.

Americans still contend year-to-year with the legacy of the 2001 terror attack that destroyed the World Trade Center in New York. According to a recent study, several hundred young adults who were exposed to toxic dust and debris on 9/11 as children are now showing early signs of risk for heart disease.

Researchers at NYU Langone Health examined the blood of 308 people who had either lived or studied in Lower Manhattan as children on the day of the attacks. Nearly half of the participants came into direct contact with dust and debris from ground zero.

The analysis, which was conducted by a team led by Dr. Leonardo Trasande, a health epidemiologist and associate professor at NYU School of Medicine, found that those with higher levels of the chemicals known to be in debris from the World Trade Center also had greater levels of artery-hardening fats in their blood.

Several studies have examined the mental health effects of witnessing the tragedy on 9/11 and studied the toxic impact on the health of first responders, but according to Trasande, this is the first study to look at the long-term cardiovascular health risks of children exposed to chemicals when the World Trade Center was attacked.

“Children are a vulnerable population that was unfortunately exposed to the debris and dust from ground zero on 9/11,” Dr. Trasande told Seeker. “There is still a big gap of research when it comes to the potential risks that may have an impact on their physical health.”

The study participants are part of the World Trade Center Health Registry (WTCHR), which is tracking both the physical and mental health effects of 2,900 children who lived or went to school in Lower Manhattan on 9/11.

Children cover their mouths in the SoHo neighborhood of New York on September 12, 2001. Smoke filled the air all over lower Manhattan in the aftermath of Tuesday's terrorist attack and destruction of the World Trade Center.

In January, a Langone analysis of several WTCHR participants showed that those who were present near ground zero on 9/11 had higher levels of PFAS (perfluoroalkyl substances) in their blood than the participants who were not in the city on that day.

“We found that higher serum levels of PFAS are associated with increased blood lipids,” Trasande said. “Blood lipids are an early marker of cardiovascular risk, and if ignored may lead to adverse outcomes later in life like coronary artery disease or stroke.”

Luckily, these risk factors “can be avoided if identified earlier on,” Trasande noted, explaining that they can be somewhat controlled with diet and exercise.

“Understanding these risks is essential for continuous monitoring and early interventions to prevent adverse cardio-metabolic outcomes in the future,” he said.

The presence of PFAS in the air on the day of the attacks came from the many electronics and furniture that burned in the World Trade Center after terrorists flew airliners into the two towers. PFAS was once widely used in the US to make plastics more flexible but the government discontinued it after learning its many adverse health effects, including lower-than-normal birth weights and brain damage.

“Our study showed that there was an association with PFAS and increased blood lipid levels in children exposed to WTC debris and dust,” Trasande said. “During this unfortunate tragedy it was nearly impossible to avoid the chemicals that were being released into the environment, however, there were various chemical pollutants that were released that day. Further studies are clearly needed to identify which other pollutants or collection of pollutants may have affected physical health.”

Another study from the Journal of Psychiatric Research found that people exposed to dust on 9/11 also had raised blood levels of C-reactive protein (CRP). CRP can cause inflammation and is linked to higher rates of post-traumatic stress disorder. It was discovered that people with high levels of CRP had a 12 percent greater risk of PTSD than people whose CRP was not elevated.

Since the World Trade Center collapse 16 years ago, thousands of firefighters, emergency personnel, and other first responders have suffered illnesses related to 9/11. More than 5,400 people have been diagnosed with cancer caused by breathing in the toxic chemicals in the air during the hours and days after the attacks. On Monday’s anniversary, 32 FDNY firefighters, whose deaths were caused by 9/11-related illnesses, will be added to the list of the fallen.

Payouts by the 9/11 Victim Compensation Fund have reached nearly $3 billion since it was reopened. The VCF was created in 2001 to support families of those injured and killed on 9/11 and paid out $7 billion before it was closed in 2004. Due to the abundance of illnesses related to the attacks, it reopened in 2011 to provide additional financial support for victims and their loved ones.

From Seeker

USA threatened by more frequent flooding

Street flooding in Miami

The East Coast of the United States is threatened by more frequent flooding in the future. This is shown by a recent study by the Universities of Bonn, South Florida, and Rhode Island. According to this, the states of Virginia, North Carolina, and South Carolina are most at risk. Their coastal regions are being immersed by up to three millimeters per year -- among other things, due to human intervention. The work is published in the journal Scientific Reports by the Nature Publishing Group.

Cities such as Miami on the East Coast of the USA are being affected by flooding more and more frequently. The causes are often not hurricanes with devastating rainfall such as Katrina, or the recent hurricanes Harvey or Irma. On the contrary: flooding even occurs on sunny, relatively calm days. It causes damage to houses and roads and disrupts traffic, yet does not cost any people their lives. It is thus also known as 'nuisance flooding'.

And this nuisance is set to occur much more frequently in the future. At least researchers from the Universities of Bonn, South Florida, and Rhode Island are convinced of this. The international team evaluated data from the East Coast of America, including GPS and satellite measurements. These show that large parts of the coastal region are slowly yet steadily sinking into the Atlantic Ocean.

"There are primarily two reasons for this phenomenon," explains Makan A. Karegar from the University of South Florida, currently a guest researcher at the Institute of Geodesy and Geoinformation at the University of Bonn. "During the last ice age around 20,000 years ago, large parts of Canada were covered by an ice sheet. This tremendous mass pressed down on the continent." Some areas of Earth's mantle were thus pressed sideways under the ice, causing the coastal regions that were free of ice to be raised. "When the ice sheet then melted, this process was reversed," explains Karegar. "The East Coast has thus been sinking back down for the last few thousand years."

This geological effect explains the submerging of the coastal regions, but only in part. In the last decade, the area between 32 and 38 degrees latitude has been sinking more quickly than in the previous millennia -- in some cases, by more than three millimeters a year. The melting of the ice sheet is responsible for a maximum of a third of this.

The researchers assume that it is caused by the significant use of groundwater in the corresponding region. Water allows the land mass to swell up to some degree -- similar to carbon dioxide bubbles in cake mix. "When groundwater is removed, the land mass can be compressed more greatly," says Karegar. "It practically collapses into itself and thus sinks even more."

"Depending on the distance from the sea, the creation of reservoirs can also contribute to the sinking or even the raising of the coastal region," says Prof. Jürgen Kusche from the Institute of Geodesy and Geoinformation. "This effect was taken into account with the help of satellite measurements, which were evaluated in our working group."

60 centimeters in 300 years

Many cities on the East Coast of America were founded at the end of the 16th or start of the 17th centuries. The researchers have calculated that these cities lie at least 45 centimeters lower today than back then, solely due to the glacier effect. In recent years, they have even been sinking much more rapidly in some places due to the removal of groundwater. A further factor is the rising sea level due to global warming, an effect that now also totals more than three millimeters per year and is responsible for another 15 centimeters of submerged land.

Read more at Science Daily

The evolutionary origin of the gut

Early embryonic stage of Nematostella vectensis.

How did the gut, the skin and musculature evolve? This question concerns scientists for more than a century. Through the investigation of the embryonic development of sea anemones, a very old animal lineage, researchers from the University of Vienna have now come to conclusions which challenge the 150 year-old hypothesis of the homology (common evolutionary origin) of the germ layers that form all later organs and tissues.

According to a 150 year-old hypothesis, all tissues and organs in our body derive from one of three germ layers that are established during early embryogenesis. This "germ layer hypothesis" states that skin and nervous system derive from the outer ectoderm layer, the gut and some inner organs, like the pancreas, derive from the inner endoderm layer, while muscles and gonads stem from the middle layer, the mesoderm. Early on, researchers noted a fundamental difference in the number of germ layers in different animal groups.

While most animals, like humans, insects and worms, develop from three germ layers, the cnidarians (corals, sea anemones or jellyfish) lack the intermediate layer and present only two cell layers during development and throughout life. The emergence of mesoderm as the third intermediate germ layer is considered a key event during the evolution of complex animals. So far, however, it was controversial how mesoderm has evolved, and how the two cnidarian germ layers relate to the three layers in most other animals. A new publication from the laboratory of Ulrich Technau at the Department for Molecular Evolution and Development of the University of Vienna presents a fundamentally new view of the evolution of germ layers.

The inner-most, gut-forming endoderm has always been considered as evolutionary related between cnidarians and other animals. In their study, Technau and colleagues have now tested this hypothesis by tracing the embryonic origin of digestive enzyme-producing cells as well as their developmental regulator genes typical of the gut and pancreas in a sea anemone. The authors show that in sea anemones, against all previous beliefs, digestive enzyme- and insulin-producing gland cells do not develop from endoderm but from the ectodermal part of the mouth, the pharynx. "I was puzzled when I first saw that all endoderm derivatives of sea anemones are totally devoid of digestive gland cells. That was not what is taught in biology textbooks" explains Patrick Steinmetz, who contributed most of the experiments and is now a group leader at the University of Bergen in Norway.

"The results completely change the way we think of the origin of germ layers. It means that 'endoderm' in sea anemones and vertebrates, although they are called the same, are actually not evolutionary related" adds Ulrich Technau. If the mouth ectoderm of the sea anemone and not the endoderm corresponds to the vertebrate gut and pancreas, then what is the vertebrate correlate of the sea anemone endoderm? When Steinmetz and Technau dwelled deeper into this question, they found strong similarities between the cnidarian endoderm and the intermediate mesoderm layer: both share a large number of regulatory genes, and both give rise to similar cell types such as muscle or gonad cells. The sea anemone thus shows a clear correlate of mesoderm, but not in an intermediate position as found in three-layered animals. Positioning, and not novel emergence, of tissue in-between the gut and skin was thus the key event that led to the evolution of three-layered animals.

Read more at Science Daily