Humans develop more slowly than mice because our chemistry is different

 Scientists from the RIKEN Center for Biosystems Dynamics Research, European Molecular Biology Laboratory (EMBL) Barcelona, Universitat Pompeu Fabra, and Kyoto University have found that the "segmentation clock" -- a genetic network that governs the body pattern formation of embryos -- progresses more slowly in humans than in mice because the biochemical reactions are slower in human cells. The differences in the speeds of biochemical reactions may underlie differences between species in the tempo of development.

In the early phase of the development of vertebrates, the embryo develops into a series of "segments" that eventually differentiate into different types of tissues, such as muscles or the ribs. This process is known to be governed by an oscillating biochemical process, known as the segmentation clock, which varies between species. For example, it is about two hours in mice, and about five hours in humans. Why the length of this cycle varies between species has remained a mystery, however.

To solve this mystery, the group began experiments using embryonic stem cells for mice and induced pluripotent stem (iPS) cells which they transformed into presomitic mesoderm (PSM) cells, the cells that take part in the segmentation clock.

They began by examining whether something different was happening in the network of cells or whether there was a difference in the process within cells. They found, using experiments that either blocked important signals or put cells in isolation, that the latter is true.

With the understanding that processes within cells were key, they suspected that the difference might be within the master gene -- HES7 -- which controls the process by repressing its own promoter, and did a number of complex experiments where they swapped the genes between the human and mouse cells, but this did not change the cycle.

According to corresponding author Miki Ebisuya, who performed the work both at RIKEN BDR and EMBL Barcelona, "Failing to show a difference in the genes left us with the possibility that the difference was driven by different biochemical reactions within the cells." They looked at whether there were differences in factors such as the degradation rate of the HES7 protein, an important factor in the cycle. They looked at a number of processes including how quickly mouse and human proteins were degraded and found, confirming the hypothesis, that both proteins were degraded more slowly in human cells than in mouse cells. There were also differences in the time it took to transcribe and translate HES7 into proteins, and the time it took for HES7 introns to be spliced. "We could thus show," says Ebisuya, "that it was indeed the cellular environment in human and mouse cells that is the key to the differential biochemical reaction speeds and thus differential time scales."

Read more at Science Daily

Uncovering the clock that sets the speed of embryo development

 Why do pregnancies last longer in some species than others? Researchers at the Francis Crick Institute have found the clock that sets the speed of embryonic development and discovered the mechanism is based on how proteins are made and dismantled. The study, published in Science, could also help us understand how different mammals evolved from one another and help refine methods for regenerative medicine.

Different development time-scales

All mammals follow the same steps to grow from embryo to adult. This involves the same series of events, in the same sequence, using similar genes and molecular signals. However, the speed of progress through these steps differs considerably from one species to another. For instance, motor neurons -- the nerve cells that control muscle movement -- take about three days to develop in mice, but over a week to develop in humans.

To understand what governs this speed in different species, researcher Teresa Rayon and colleagues in James Briscoe's Developmental Dynamics lab at the Crick first grew motor neurons from stem cells in the lab, so they could time the cells' development without any influence from the environment within the embryo.

Using mouse and human stem cells, they saw the same difference in speed between the species. Human motor neurons took more than twice as long as mouse motor neurons to form, so they knew the answer must lie within the cells themselves, not the surrounding environment.

They also checked if the genes were responsible, by introducing human DNA sequences into mouse cells. However, this did not alter the speed of development, so the answer wasn't in the genes either.

Finding an answer in the proteins

Instead, the researchers discovered that differences in the speed at which proteins are broken down and replaced explains the difference in speed between the two species. Proteins are constantly turned over -- made and dismantled -- in cells, and this happens twice as fast in mouse cells compared to human cells. This faster rate of protein turnover in mouse cells accounts for the faster pace of motor neuron formation.

Teresa Rayon explained, "Human and mouse motor neurons use the same genes and molecules for their embryonic development, it just takes longer for the process to play out in humans. Proteins are simply more stable in humans than mouse embryos and this slows the rate of human development."

"It's as if mouse and human embryos are reading the same musical score and playing the same tune but the metronome ticks more slowly in humans than in mice. Now that we've found the metronome, we want to understand how to change its speed."

How this impacts research and treatments

Understanding the mechanisms that control the speed of development has implications for regenerative medicine and for the use of stem cells in understanding disease. Being able to speed up or slow down the development of stem cells could help refine methods for the production of specific types of cells for research and therapeutic applications and it might also provide insight relevant for slowing the growth of cells in diseases such as cancer.

Read more at Science Daily

Climate change impacts astronomical observations

 Climate changes associated with global warming can affect astronomical observations. That is the result of a study involving scientists from the University of Cologne. The international research team investigated a range of climate parameters at the Very Large Telescope (VLT) at the Paranal in the Atacama Desert in Chile, where the European Southern Observatory (ESO) operates its telescopes. Among other things, the team evaluated the data for temperature, wind speed and wind direction, and the water vapour content in the atmosphere over a period of several decades. This revealed an increase in temperatures above the world average and also increasing image blur due to air turbulence -- so-called seeing.

The study 'The impact of climate change on astronomical observations' was published in the current issue of Nature Astronomy and can be viewed online. Its results are not only important for astronomers to adapt their observations to changing environmental conditions, but must also be taken into account when planning new large telescopes -- such as the Extremely Large Telescope (ELT), which is currently being built near the Paranal.

The Cologne-based scientists Professor Dr Susanne Crewell and Christoph Böhm from the Institute of Geophysics and Meteorology were involved in the study. In the past, they had already explored various aspects of the past, present and future climate at the telescope's site in the framework of Collaborative Research Centre 1211 'Earth -- Evolution at the Dry Limit'. The first author of the article is Faustine Cantalloube from the Max Planck Institute for Astronomy in Heidelberg.

The researchers investigated the extent to which climate change affects astronomy and in particular the quality of observations. The team focused on the Paranal Observatory in northern Chile because it has a whole range of environmental sensors that document local meteorological conditions. These measurements yielded one of the most comprehensive data sets over the last three decades at a largely untouched location.

Based on this data set, astronomers, climate researchers, atmosphere scientists, and meteorologists joined forces to identify important meteorological parameters that play a role in the quality of astronomical observations. The data allowed them to analyse long-term trends over a period of more than thirty years to determine the impact of climate change on future observations. Using four examples, they showed how climate change is already affecting, or might affect the operation of an astronomical observatory in future. The VLT, operated by ESO, was served as an example.

'The data showed a 1.5 ° C increase in near-ground temperature over the last four decades at the Paranal Observatory. This is slightly higher than the worldwide average of 1°C since the pre-industrial age,' said Susanne Crewell. Since the original telescope cooling system was not designed for such warm conditions, the quality of observations is increasingly endangered by more frequent turbulences -- a consequence of the rise in temperature. The expected rise of 4° C (the most pessimistic scenario of the ICCP climate simulations) within the next century thus has to be taken into account in the construction of the 39-metre Extremely Large Telescope (ELT) at a nearby site.

In particular, astronomers face the challenge of a reduction in the so-called 'dome seeing', a reduction in resolution due to turbulence within the telescope dome. The researchers furthermore noticed an increase in turbulence in the air layer near the ground, making images blurred since cold and warm air layers with different refractive indices alternate more quickly. However, attributing this to climate change is difficult, since there were also constructional changes. The increase in wind shear in the upper troposphere in connection with the jet stream also leads to a so-called 'wind-driven halo'. This phenomenon appears when atmospheric turbulence conditions vary faster than the telescope's control system can correct them. This limits the contrast capabilities of the instrument and could potentially limit exoplanet studies. An increase in water vapour in the atmosphere moreover could lead to a reduction of the astronomical signal.

Read more at Science Daily

The key to happiness: Friends or family?

 Think spending time with your kids and spouse is the key to your happiness? You may actually be happier getting together with your friends, said SMU psychology professor Nathan Hudson.

Hudson's research finds that people report higher levels of well-being while hanging with their friends than they do with their romantic partner or children. In fact, being around romantic partners predicted the least amount of happiness among these three groups, reveals a study published in the Journal of Personality and Social Psychology.

Hudson stressed, however, that the finding has more to do with the activity than the person it is shared with. That's because people tend to spend more of their time doing enjoyable activities with friends than they do with family members, who occasionally find themselves together doing unpleasant tasks like chores or caretaking duties.

"Our study suggests that this doesn't have to do with the fundamental nature of kith versus kin relationships," he said. "When we statistically controlled for activities, the 'mere presence' of children, romantic partners, and friends predicted similar levels of happiness. Thus, this paper provides an optimistic view of family and suggests that people genuinely enjoy their romantic partners and children."

More than 400 study participants were asked to think back on times with their friends or family -- identify the activity they shared -- and rate whether those experiences left them feeling various emotions, such as happy, satisfied, and with a sense of meaning. Each emotion was rated from 0 (almost never) to 6 (almost always).

This information and other responses about how study participants felt at different times allowed Hudson and his co-authors, Richard E. Lucas and M. Brent Donnellan, to estimate rates of happiness with their friends and family. Lucas and Donnellan are both from Michigan State University.

The activities people most frequently perform while they're with their romantic partners include socializing, relaxing, and eating. People tend to do similar activities when they are with their friends, too. They just do a lot more of these enjoyable tasks while hanging with their friends and a lot less housework, the study found. For instance, 65 percent of experiences with friends involved socializing, but only 28 percent of the time shared with partners.

Spending time with their children also meant more time doing things that had a negative association, such as housework and commuting.

However, the activity that people reported most often with their offspring -- childcare -- was viewed positively. And overall, people report feeling similar levels of well-being while in the presence of friends, partners, and children once the activity was taken out of the equation.

Read more at Science Daily

Researchers develop simple method to 3D print milk products

 Researchers from the Singapore University of Technology and Design (SUTD) developed a method to perform direct ink writing (DIW) 3D printing of milk-based products at room temperature, while maintaining its temperature sensitive nutrients.

3D printing of food has been achieved by different printing methods, including the widely used selective laser sintering (SLS) and hot-melt extrusion methods. However, these methods are not always compatible with temperature-sensitive nutrients found in certain types of food. For instance, milk is rich in both calcium and protein, but as these nutrients are temperature sensitive, milk is unsuitable for 3D printing using the aforementioned printing methods which require high temperature. While the cold-extrusion is a viable alternative, it often requires rheology modifiers or additives to stabilize printed structures. Optimizing these additives is a complex and judicious task.

To tackle these limitations, the research team from SUTD's Soft Fluidics Lab changed the rheological properties of the printing ink and demonstrated DIW 3D printing of milk by cold-extrusion with a single milk product -- powdered milk. The team found that the concentration of milk powder allowed for the simple formulation of 3D-printable milk inks using water to control the rheology. Extensive characterizations of the formulated milk ink were also conducted to analyse their rheological properties and ensure optimal printability.

"This novel yet simple method can be used in formulating various nutritious foods including those served to patients in hospitals for their special dietary needs," said the lead author and Ph.D. candidate from SUTD, Mr Lee Cheng Pau.

"Cold-extrusion does not compromise heat-sensitive nutrients and yet offers vast potential in 3D printing of aesthetically pleasing, nutritionally controlled foods customized for individual requirements," added Assistant Professor Michinao Hashimoto, the principal investigator of the study.

From Science Daily

Engineers produce a fisheye lens that's completely flat

 To capture panoramic views in a single shot, photographers typically use fisheye lenses -- ultra-wide-angle lenses made from multiple pieces of curved glass, which distort incoming light to produce wide, bubble-like images. Their spherical, multipiece design makes fisheye lenses inherently bulky and often costly to produce.

Now engineers at MIT and the University of Massachusetts at Lowell have designed a wide-angle lens that is completely flat. It is the first flat fisheye lens to produce crisp, 180-degree panoramic images. The design is a type of "metalens," a wafer-thin material patterned with microscopic features that work together to manipulate light in a specific way.

In this case, the new fisheye lens consists of a single flat, millimeter-thin piece of glass covered on one side with tiny structures that precisely scatter incoming light to produce panoramic images, just as a conventional curved, multielement fisheye lens assembly would. The lens works in the infrared part of the spectrum, but the researchers say it could be modified to capture images using visible light as well.

The new design could potentially be adapted for a range of applications, with thin, ultra-wide-angle lenses built directly into smartphones and laptops, rather than physically attached as bulky add-ons. The low-profile lenses might also be integrated into medical imaging devices such as endoscopes, as well as in virtual reality glasses, wearable electronics, and other computer vision devices.

"This design comes as somewhat of a surprise, because some have thought it would be impossible to make a metalens with an ultra-wide-field view," says Juejun Hu, associate professor in MIT's Department of Materials Science and Engineering. "The fact that this can actually realize fisheye images is completely outside expectation.

This isn't just light-bending -- it's mind-bending."

Hu and his colleagues have published their results in the journal Nano Letters. Hu's MIT coauthors are Mikhail Shalaginov, Fan Yang, Peter Su, Dominika Lyzwa, Anuradha Agarwal, and Tian Gu, along with Sensong An and Hualiang Zhang of UMass Lowell.

Design on the back side

Metalenses, while still largely at an experimental stage, have the potential to significantly reshape the field of optics. Previously, scientists have designed metalenses that produce high-resolution and relatively wide-angle images of up to 60 degrees. To expand the field of view further would traditionally require additional optical components to correct for aberrations, or blurriness -- a workaround that would add bulk to a metalens design.

Hu and his colleagues instead came up with a simple design that does not require additional components and keeps a minimum element count. Their new metalens is a single transparent piece made from calcium fluoride with a thin film of lead telluride deposited on one side. The team then used lithographic techniques to carve a pattern of optical structures into the film.

Each structure, or "meta-atom," as the team refers to them, is shaped into one of several nanoscale geometries, such as a rectangular or a bone-shaped configuration, that refracts light in a specific way. For instance, light may take longer to scatter, or propagate off one shape versus another -- a phenomenon known as phase delay.

In conventional fisheye lenses, the curvature of the glass naturally creates a distribution of phase delays that ultimately produces a panoramic image. The team determined the corresponding pattern of meta-atoms and carved this pattern into the back side of the flat glass.

'We've designed the back side structures in such a way that each part can produce a perfect focus," Hu says.

On the front side, the team placed an optical aperture, or opening for light.

"When light comes in through this aperture, it will refract at the first surface of the glass, and then will get angularly dispersed," Shalaginov explains. "The light will then hit different parts of the backside, from different and yet continuous angles. As long as you design the back side properly, you can be sure to achieve high-quality imaging across the entire panoramic view."

Across the panorama

In one demonstration, the new lens is tuned to operate in the mid-infrared region of the spectrum. The team used the imaging setup equipped with the metalens to snap pictures of a striped target. They then compared the quality of pictures taken at various angles across the scene, and found the new lens produced images of the stripes that were crisp and clear, even at the edges of the camera's view, spanning nearly 180 degrees.

"It shows we can achieve perfect imaging performance across almost the whole 180-degree view, using our methods," Gu says.

In another study, the team designed the metalens to operate at a near-infrared wavelength using amorphous silicon nanoposts as the meta-atoms. They plugged the metalens into a simulation used to test imaging instruments. Next, they fed the simulation a scene of Paris, composed of black and white images stitched together to make a panoramic view. They then ran the simulation to see what kind of image the new lens would produce.

"The key question was, does the lens cover the entire field of view? And we see that it captures everything across the panorama," Gu says. "You can see buildings and people, and the resolution is very good, regardless of whether you're looking at the center or the edges."

The team says the new lens can be adapted to other wavelengths of light. To make a similar flat fisheye lens for visible light, for instance, Hu says the optical features may have to be made smaller than they are now, to better refract that particular range of wavelengths. The lens material would also have to change. But the general architecture that the team has designed would remain the same.

The researchers are exploring applications for their new lens, not just as compact fisheye cameras, but also as panoramic projectors, as well as depth sensors built directly into smartphones, laptops, and wearable devices.

Read more at Science Daily

Discovery of microbes with mixed membranes sheds new light on early evolution of life

 Current research suggests that more complex life-forms, including humans, evolved from a symbiosis event between bacteria and another single-celled organism known as archaea. However, evidence of a transition period in which the two organisms mixed where nowhere to be found. That is, until now. In the deep waters of the Black Sea, a team of scientists found microbes that can make membrane lipids of unexpected origin.

Cells are surrounded by a layer of membrane lipids that protect them from changes in their environment such as temperature, much in the same way that our skin changes when we are cold or exposed to the sun. Lead author and NIOZ senior scientist Laura Villanueva explains why they make such interesting biomarkers. 'When a cell dies, these lipids preserve like fossils and hold ancient-old information on Earths' early environmental conditions.' Our tree of life includes small and simple cells (Bacteria and Archaea) and more complex cells (Eukaryotes), including animals and humans. Bacteria and Eukaryotes share a similar lipid membrane. Looking at Archaea, their 'skin' or membrane looks very different and is primarily designed to help these microorganisms to survive in extreme environments. Villanueva: 'This "lipid divide," or difference in membranes between Bacteria and Eukaryotes on the one hand and Archaea on the other, is believed to have happened after the emergence of Bacteria and Archaea from the last universal cellular ancestor (LUCA).'

Missing piece hidden in the deep Black Sea

The leading theory is that Eukaryotes evolved from a symbiosis event between archaeal and bacterial cells in which the archaeal cell was the host. But how does this work when their 'skins' are so different and share no sign of common ancestry? Villanueva: 'To explain the creation of more complex life-forms, the archaeal membrane must have made a switch to a bacterial type membrane. Such a switch likely needed a transition period in which the two membrane types were mixed.' However, mixed lipid membranes had never been found in microbes until the team of Villanueva made an unexpected discovery in de deep waters of the Black Sea.

Villanueva: 'We found a possible missing piece of this puzzle in the Black Sea. Here, an abundant group of bacteria thrive in the deep-sea, absent of oxygen and with high sulfide concentration. We discovered that the genetic material of this group did not only carry pathway genes for bacterial lipids but archaeal ones as well.' The peculiarity was also found in the genetic material of other, closely related Bacteria and supports the idea that this ability to create 'mixed' membranes is more widespread than previously thought. This discovery sheds new light on the evolution of all cellular life forms and may have important consequences for the interpretation of archaeal lipid fossils in the geological record and paleoclimate reconstructions.

Read more at Science Daily

Climate change threatens Komodo dragons

 The world's largest lizard, the Komodo dragon, could be driven to extinction by climate change unless significant measures to intervene are taken soon.

A new international study, led by the University of Adelaide and Deakin University, has found that the impact of both global warming and sea-level rise threatens the extinction of Komodo dragons, which already have restricted habitats, and this must be better incorporated into conservation strategies.

"Climate change is likely to cause a sharp decline in the availability of habitat for Komodo dragons, severely reducing their abundance in a matter of decades," says lead author Dr Alice Jones from the University of Adelaide's School of Biological Sciences. "Our models predict local extinction on three of the five island habitats where Komodo dragons are found today."

The Komodo dragon, Varanus komodoensis, is the world's most iconic lizard species which has existed on Earth for more than a million years, but only an estimated 4000 individuals survive in the wild. They are endemic to five islands in southeast Indonesia: Komodo, Rinca, Nusa Kode and Gili Motang which are part of Komodo National Park, and Flores, the fifth and largest island which has three nature reserves.

"Current-day conservation strategies are not enough to avoid species decline in the face of climate change. This is because climate change will compound the negative effects of already small, isolated populations," says Dr Jones.

"Interventions such as establishing new reserves in areas that are predicted to sustain high-quality habitats in the future, despite global warming, could work to lessen the effects of climate change on Komodo dragons.

This study, which is published in the journal Ecology and Evolution, is the result of many years of fieldwork on the ecology and conservation status of Komodo dragons.

"Using this data and knowledge in conservation models has provided a rare opportunity to understand climate change impacts on Indonesia's exceptional but highly vulnerable biodiversity," says co-author Dr Tim Jessop, School of Life and Environmental Sciences, Deakin University.

Importantly, the research project involved close collaboration with the Komodo National Park and the Eastern Lesser Sunda Cen¬tral Bureau for Conservation of Natural Resources.

"The severity and extent of human actions impacting Komodo dragon populations, especially on Flores Island, are only just being realised," says co-author Deni Purwandana, Coordinator of the Komodo Survival Program.

"Having an insight into future impacts of climate change provides new possibilities to work with conservation agencies and local communities to find on-ground solutions that will limit climate and other threats to Komodo dragons and their habitats."

The researchers say climate-change-informed decisions should be a common part of conservation practice.

"Our conservation models show that Komodo dragons on two protected large islands are less vulnerable to climate change. However, even these island habitats might not provide an adequate insurance policy for the survival of the species," says Associate Professor Damien Fordham from the University of Adelaide's Environment Institute.

"Conservation managers in coming decades may need to consider translocating animals to sites where Komodo dragons have not been found for many decades. This scenario can be tested easily using our approach.

Read more at Science Daily

Device could help detect signs of extraterrestrial life

 Although Earth is uniquely situated in the solar system to support creatures that call it home, different forms of life could have once existed, or might still exist, on other planets. But finding traces of past or current lifeforms on other worlds is challenging. Now, researchers reporting in ACS' Analytical Chemistry have developed a fully automated microchip electrophoresis analyzer that, when incorporated into a planetary rover, could someday detect organic biosignatures in extraterrestrial soil.

One critical piece of evidence for life beyond Earth is the presence of certain organic molecules. Previous missions to Mars have relied on gas chromatography coupled to mass spectrometry (GC-MS) to separate and detect compounds. However, the technique has limitations for the analysis of some molecules, such as organic acids, especially when water, minerals or salts are also in the sample. Microchip electrophoresis (ME)-based separations, followed by laser-induced fluorescence (LIF) detection, would be ideal, but current instruments are only partially automated, which wouldn't work for interplanetary missions. Peter Willis and colleagues wanted to develop a portable, battery-powered ME-LIF instrument that could accept a sample and perform labeling, separation and detection of organic molecules, all in a fully automated fashion.

The researchers made a device that included two microchips -- one for processing and labeling a liquid sample, and the other (the ME chip) for separating compounds -- and an LIF detection system. After optimizing the device, the researchers put it to the test in a simulated Mars mission in a Chilean desert. The team coupled the analyzer to a portable subcritical water extractor on a remotely deployed rover system. The rover drilled into the soil to collect samples, which were delivered to the extractor. Then, water was added to the soil samples, and they were heated to extract compounds for analysis. The device detected parts per billion levels of amino acids in soil from three of four drilling locations. Importantly, the sensitivity was three orders of magnitude higher than that reported for GC-MS-based methods. Although more work is needed to ready the instrument for spaceflight and extraterrestrial conditions, this research lays the foundation for developing ME-LIF instruments for missions seeking signs of life beyond Earth, the researchers say.

From Science Daily

Venus' ancient layered, folded rocks point to volcanic origin

 An international team of researchers has found that some of the oldest terrain on Venus, known as tesserae, have layering that seems consistent with volcanic activity. The finding could provide insights into the enigmatic planet's geological history.

Tesserae are tectonically deformed regions on the surface of Venus that are often more elevated than the surrounding landscape. They comprise about 7% of the planet's surface, and are always the oldest feature in their immediate surroundings, dating to about 750 million years old. In a new study appearing in Geology, the researchers show that a significant portion of the tesserae have striations consistent with layering.

"There are generally two explanations for tesserae -- either they are made of volcanic rocks, or they are counterparts of Earth's continental crust," says Paul Byrne, associate professor of planetary science at North Carolina State University and lead author of the study. "But the layering we find on some of the tessera isn't consistent with the continental crust explanation."

The team analyzed images of Venus' surface from NASA's 1989 Magellan mission, which used radar to image 98% of the planet through its dense atmosphere. While researchers have studied the tesserae for decades, prior to this work the layering of the tesserae hasn't been recognized as widespread. And according to Byrne, that layering would not be possible if the tesserae were portions of continental crust.

"Continental crust is composed mainly of granite, an igneous rock formed when tectonic plates move and water is subducted from the surface," Byrne says. "But granite doesn't form layers. If there's continental crust on Venus, then it's below the layered rocks we see.

"Aside from volcanic activity, the other way to make layered rock is through sedimentary deposits, like sandstone or limestone. There isn't a single place today on Venus where these kinds of rocks could form. The surface of Venus is as hot as a self-cleaning oven and the pressure is equivalent to being 900 meters (about 985 yards) underwater. So the evidence right now points to some portions of the tesserae being made up of layered volcanic rock, similar to that found on Earth."

Byrne hopes that the work will help to shed light on more of Venus' complicated geological history.

"While the data we have now point to volcanic origins for the tesserae, if we were one day able to sample them and find that they are sedimentary rocks, then they would have had to have formed when the climate was very different -- perhaps even Earth-like," Byrne says.

Read more at Science Daily

World's oldest animal sperm found in tiny crustaceans trapped in Myanmar amber

 An international collaboration between researchers at Queen Mary University of London and the Chinese Academy of Science in Nanjing has led to the discovery of world's oldest animal sperm inside a tiny crustacean trapped in amber around 100 million years ago in Myanmar.

The research team, led by Dr He Wang of the Chinese Academy of Science in Nanjing, found the sperm in a new species of crustacean they named Myanmarcypris hui. They predict that the animals had sex just before their entrapment in the piece of amber (tree resin), which formed in the Cretaceous period.

Fossilised sperm are exceptionally rare; previously the oldest known examples were only 17 million years old. Myanmarcypris hui is an ostracod, a kind of crustacean that has existed for 500 million years and lives in all kinds of aquatic environments from deep oceans to lakes and rivers. Their fossil shells are common and abundant but finding specimens preserved in ancient amber with their appendages and internal organs intact provides a rare and exciting opportunity to learn more about their evolution.

Professor Dave Horne, Professor of Micropalaeontology at Queen Mary University of London said: "Analyses of fossil ostracod shells are hugely informative about past environments and climates, as well as shedding light on evolutionary puzzles, but exceptional occurrences of fossilised soft parts like this result in remarkable advances in our understanding."

During the Cretaceous period in what is now Myanmar, the ostracods were probably living in a coastal lagoon fringed by trees where they became trapped in a blob of tree resin. The Kachin amber of Myanmar has previously yielded outstanding finds including frogs, snakes and a feathered dinosaur tail. Bo Wang, also of the Chinese Academy of Science in Nanjing added: "Hundreds of new species have been described in the past five years, and many of them have made evolutionary biologists re-consider long-standing hypotheses on how certain lineages developed and how ecological relationships evolved."

The study, published in Royal Society Proceedings B, also has implications for understanding the evolutionary history of an unusual mode of sexual reproduction involving "giant sperm."

The new ostracod finds may be extremely small but in one sense they are giants. Males of most animals (including humans) typically produce tens of millions of really small sperm in very large quantities, but there are exceptions. Some tiny fruit flies (insects) and ostracods (crustaceans) are famous for investing in quality rather than quantity: relatively small numbers of "giant" sperm that are many times longer than the animal itself, a by-product of evolutionary competition for reproductive success. The new discovery is not only by far the oldest example of fossil sperm ever found but also shows that these ostracods had already evolved giant sperm, and specially-adapted organs to transfer them from male to female, 100 million years ago.

Each ostracod is less than a millimetre long. Using X-ray microscopy the team made computer-aided 3-D reconstructions of the ostracods embedded in the amber, revealing incredible detail. "The results were amazing -- not only did we find their tiny appendages to be preserved inside their shells, we could also see their reproductive organs," added He Wang. "But when we identified the sperm inside the female, and knowing the age of the amber, it was one of those special Eureka-moments in a researcher's life."

Wang's team found adult males and females but it was a female specimen that contained the sperm, indicating that it must have had sex shortly before becoming trapped in the amber. The reconstructions also revealed the distinctive muscular sperm pumps and penises (two of each) that male ostracods use to inseminate the females, who store them in bag-like receptacles until eggs are ready to be fertilised.

Such extensive adaptation raises the question of whether reproduction with giant sperms can be an evolutionarily-stable character. "To show that using giant sperms in reproduction is not an extinction-doomed extravagance of evolution, but a serious long-term advantage for the survival of a species, we need to know when they first appeared" says co-author Dr Renate Matzke-Karasz of Ludwig-Maximilians-University in Munich.

Read more at Science Daily

Scientist searches for stellar phosphorus to find potentially habitable exoplanets

 A Southwest Research Institute scientist has identified stellar phosphorus as a probable marker in narrowing the search for life in the cosmos. She has developed techniques to identify stars likely to host exoplanets, based on the composition of stars known to have planets, and proposes that upcoming studies target stellar phosphorus to find systems with the greatest probability for hosting life as we know it.

"When searching for exoplanets and trying to see whether they are habitable, it's important that a planet be alive with active cycles, volcanoes and plate tectonics," said SwRI's Dr. Natalie Hinkel, a planetary astrophysicist and lead author of a new paper about this research in the Astrophysical Research Letters. "My coauthor, Dr. Hilairy Hartnett, is an oceanographer and pointed out that phosphorus is vital for all life on Earth. It is essential for the creation of DNA, cell membranes, bones and teeth in people and animals, and even the sea's microbiome of plankton."

Determining the elemental ratios for exoplanetary ecosystems is not yet possible, but it's generally assumed that planets have compositions similar to those of their host stars. Scientists can measure the abundance of elements in a star spectroscopically, studying how light interacts with the elements in a star's upper layers. Using these data, scientists can infer what a star's orbiting planets are made of, using stellar composition as a proxy for its planets.

On Earth, the key elements for biology are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (or CHNOPS). In today's oceans, phosphorus is considered the ultimate limiting nutrient for life as it's the least available chemical necessary for biochemical reactions.

Hinkel used the Hypatia Catalog, a publicly available stellar database she developed, to assess and compare the carbon, nitrogen, silicon, and phosphorus abundance ratios of nearby stars with those in average marine plankton, the Earth's crust, as well as bulk silicate on Earth and Mars.

"But there's so little phosphorus stellar abundance data," Hinkel said. "Phosphorus data exists for only about 1% of stars. That makes it really difficult to figure out any clear trends in between the stars, let alone the role of phosphorus in the evolution of an exoplanet."

It's not that the stars are necessarily lacking phosphorus, but it's difficult to measure the element because it's detected in a region of the light spectrum not typically observed: at the edge of the optical (or visual) wavelengths of light and infrared light. Most spectroscopic studies are not tuned to find elements in that narrow range.

"Our Sun has relatively high phosphorus and Earth biology requires a small, but noticeable, amount of phosphorus," Hinkel continued. "So, on rocky planets that form around host stars with less phosphorus, it's likely that phosphorus will be unavailable for potential life on that planet's surface. Therefore, we urge the stellar abundance community to make phosphorus observations a priority in future studies and telescope designs."

Read more at Science Daily

Can life survive a star's death? Webb telescope can reveal the answer

 When stars like our sun die, all that remains is an exposed core -- a white dwarf. A planet orbiting a white dwarf presents a promising opportunity to determine if life can survive the death of its star, according to Cornell University researchers.

In a study published in the Astrophysical Journal Letters, they show how NASA's upcoming James Webb Space Telescope could find signatures of life on Earth-like planets orbiting white dwarfs.

A planet orbiting a small star produces strong atmospheric signals when it passes in front, or "transits," its host star. White dwarfs push this to the extreme: They are 100 times smaller than our sun, almost as small as Earth, affording astronomers a rare opportunity to characterize rocky planets.

"If rocky planets exist around white dwarfs, we could spot signs of life on them in the next few years," said corresponding author Lisa Kaltenegger, associate professor of astronomy in the College of Arts and Sciences and director of the Carl Sagan Institute.

Co-lead author Ryan MacDonald, a research associate at the institute, said the James Webb Space Telescope, scheduled to launch in October 2021, is uniquely placed to find signatures of life on rocky exoplanets.

"When observing Earth-like planets orbiting white dwarfs, the James Webb Space Telescope can detect water and carbon dioxide within a matter of hours," MacDonald said. "Two days of observing time with this powerful telescope would allow the discovery of biosignature gases, such as ozone and methane."

The discovery of the first transiting giant planet orbiting a white dwarf (WD 1856+534b), announced in a separate paper -- led by co-author Andrew Vanderburg, assistant professor at the University of Wisconsin, Madison -- proves the existence of planets around white dwarfs. Kaltenegger is a co-author on this paper, as well.

This planet is a gas giant and therefore not able to sustain life. But its existence suggests that smaller rocky planets, which could sustain life, could also exist in the habitable zones of white dwarfs.

"We know now that giant planets can exist around white dwarfs, and evidence stretches back over 100 years showing rocky material polluting light from white dwarfs. There are certainly small rocks in white dwarf systems," MacDonald said. "It's a logical leap to imagine a rocky planet like the Earth orbiting a white dwarf."

The researchers combined state-of-the-art analysis techniques routinely used to detect gases in giant exoplanet atmospheres with the Hubble Space Telescope with model atmospheres of white dwarf planets from previous Cornell research.

NASA's Transiting Exoplanet Survey Satellite is now looking for such rocky planets around white dwarfs. If and when one of these worlds is found, Kaltenegger and her team have developed the models and tools to identify signs of life in the planet's atmosphere. The Webb telescope could soon begin this search.

The implications of finding signatures of life on a planet orbiting a white dwarf are profound, Kaltenegger said. Most stars, including our sun, will one day end up as white dwarfs.

Read more at Science Daily

Liquid water at 170 degrees Celsius

 Using the X-ray laser European XFEL, a research team has investigated how water heats up under extreme conditions. In the process, the scientists were able to observe water that remained liquid even at temperatures of more than 170 degrees Celsius. The investigation revealed an anomalous dynamic behaviour of water under these conditions. The results of the study, which are published in the Proceedings of the National Academy of Sciences (PNAS), are of fundamental importance for the planning and analysis of investigations of sensitive samples using X-ray lasers.

European XFEL, an international research facility, which extends from the DESY site in Hamburg to the neighbouring town of Schenefeld in Schleswig-Holstein, is home to the most powerful X-ray laser in the world. It can generate up to 27,000 intense X-ray flashes per second. For their experiments, the researchers used series of 120 flashes each. The individual flashes were less than a millionth of a second apart (exactly 0.886 microseconds). The scientists sent these pulse trains into a thin, water-filled quartz glass tube and observed the reaction of the water.

"We asked ourselves how long and how strongly water can be heated in the X-ray laser and whether it still behaves like water," explains lead author Felix Lehmkühler from DESY. "For example, does it still function as a coolant at high temperatures?" A detailed understanding of superheated water is also essential for a large number of investigations on heat-sensitive samples, such as polymers or biological samples.

"With the X-ray flashes, we were able to heat the water up to 172 degrees Celsius within a ten thousandth of a second without it evaporating," reports Lehmkühler. Such a boiling delay can normally only be observed up to about 110 degrees Celsius. "But that is not the only anomalous feature," the physicist emphasises. The scientists investigated the movement of silicon nanospheres floating in the water as markers for the dynamics in the sample. "In the extremely overheated water, we observed that the movement of silicon dioxide nanospheres deviated significantly from the expected random Brownian molecular movement. This indicates an uneven heating of the sample," says Lehmkühler. Existing theoretical models cannot yet satisfactorily explain this behaviour because they are not designed for water under these extreme conditions.

Thanks to the rapid flash sequence of the European XFEL, the researchers were able to observe the process in extreme detail. "What makes the European XFEL unique is the high repetition rate, that is, the high number of pulses per second," explains co-author Adrian Mancuso, head of the SPB/SFX instrument at the European XFEL where the experiments took place. "And we have all the instrumentation in place -- such as fast cameras, diagnostics and more -- to make these experiments possible." For instance, the Adaptive Gain Integrating Pixel Detector (AGIPD) developed by a DESY-led consortium can take around 350 serial images at intervals of only 220 billionths of a second (nanoseconds).

This setup not only allowed the superheated water to be generated, but also enabled the scientists to carry out precisely controlled series of experiments with X-ray flashes of reduced intensity. "Using silicon filters, we fine-tuned the energy of the pulses so that we were able to control exactly how much the water was heated," reports Lehmkühler. "For example, we were able to determine how strong the X-ray flashes should be so that the temperature of an aqueous sample remains more or less constant."

This enables researchers to better plan experiments with heat-sensitive samples at the X-ray laser, for example. On the other hand, the heating effect can also be used in a targeted manner if its exact course is known. The team plans to further investigate these effects also within the framework of the Centre for Molecular Water Science (CMWS), which is currently being set up at DESY.

Read more at Science Daily

Climate change triggers migration, particularly in middle-income countries

 Environmental hazards affect populations worldwide and can drive migration under specific conditions. Changes in temperature levels, increased rainfall variability, and rapid-onset disasters, such as tropical storms, are important factors as shown by a new study led by the Potsdam Institute for Climate Impact Research (PIK). Environmental migration is most pronounced in middle-income and agricultural countries but weaker in low-income countries, where populations often lack resources needed for migration. The findings make it possible to identify geographical regions that may be especially susceptible to migration movements in the future.

"Environmental factors can drive migration, but the size of the effects depends on the particular economic and sociopolitical conditions in the countries," says lead author Roman Hoffmann from PIK and the Vienna Institute of Demography of the Austrian Academy of Sciences. "In both low and high income countries environmental impacts on migration are weaker -- presumably because either people are too poor to leave and become basically trapped, or, in wealthy countries, have enough financial means to absorb the consequences. It is mainly in regions with middle incomes and a dependency on agriculture that we see strong effects."

Environmental impacts differ by contexts and types of hazards

The meta-study, which analyzed 30 previously published studies on the topic, reveals a number of fascinating patterns. It shows, for example, that impacts on migration vary by types of environmental hazards and that different hazards can re-inforce each other. "While changing temperatures in a region are found to have the strongest impact on migration, also rapid-onset disasters and changing rainfall variability and anomalies can play a role. Especially smallholder farmers rely on steady climatic conditions and suffer from changes and shocks as they have insufficient capacities to adapt," says co-author Raya Muttarak from the International Institute of Applied Systems Analysis and the Wittgenstein Centre for Demography and Global Human Capital (IIASA, VID/ÖAW, University of Vienna).

The researchers emphasize that there is no automatism at play -- environmental migration always depends on a number of economic and sociopolitical factors. The narrative of climate refugees pushing towards Europe or the US may be too simplistic. For instance, the researchers found compelling evidence that environmental changes in vulnerable countries predominantly lead to internal migration or migration to other low- and middle-income countries, rather than cross-border migration to high-income countries. Affected populations often migrate to places within their own region and eventually return to their homes within a relatively short period of time.

Localizing potential migration hotspots

The findings, published in the latest issue of Nature Climate Change, also hint at regions highly vulnerable to climate change where environmental migration may be particularly prevalent. "Our research suggests that populations in Latin America and the Caribbean, several countries in Sub-Saharan Africa, especially in the Sahel region and East Africa, as well as Western, South and Southeast Asia are particularly at risk," says co-author Anna Dimitrova from the Vienna Institute of Demography, Austrian Academy of Sciences.

Read more at Science Daily

Study reveals impact of centuries of human activity in American tropics

 The devastating effects of human activity on wildlife in the American tropics over the last 500 years are revealed in a new study published today.

More than half of the species in local 'assemblages' -- sets of co-existing species -- of medium and large mammals living in the Neotropics of Meso and South America have died out since the region was first colonised by Europeans in the 1500s.

Researchers at the University of East Anglia (UEA), in the UK, and University of São Paulo (USP), Brazil, found that human activity such as habitat change and overhunting is largely responsible for the overwhelming loss, or 'defaunation', in mammal diversity across Latin America.

The study, published in the journal Scientific Reports, compared all animal inventories at over 1000 Neotropical study sites published over the past 30 years with baseline data going back to the Colonial era.

The findings draw on a compilation of 1,029 separate mammal assemblages -- typically a few kilometres apart from each other -- spanning approximately 10,700 km and 85° of latitude across 23 countries, from Mexico to Argentina and Chile.

They reveal that the dominant cause of local species extinction and assemblage downsizing -- the reduction in body size within each assemblage -- is a direct result of habitat changes such as farming, logging and fires, and aggravated by the chronic process of overhunting.

Dr Juliano André Bogoni, a postdoctoral researcher sponsored by the São Paulo Research Foundation and working at UEA's School of Environmental Sciences, led the study with Prof Carlos Peres, also of UEA, and Prof Katia Ferraz from USP.

Dr Bogoni said: "Our findings can be used to inform international conservation policies to prevent further erosion of, or restore, native biodiversity. Further conservation efforts should be mobilized to prevent the most faunally-intact biomes, such as Amazonia and the Pantanal wetlands, from following in the footsteps of 'empty ecosystems' that are now typical of historically degraded areas such as the Brazilian Atlantic Forest and the Caatinga.

"This includes effective implementation and law enforcement in existing protected areas, and curbing political pressures to either downgrade or downsize these areas. Greater investment should be allocated to more effective control of illegal hunting, particularly commercial hunting, deforestation, and anthropogenic fires, as well as ensure that fully implemented protected areas are working."

Prof Peres said: "Sound resource management should be sensitive to the socioeconomic context, while recruiting rather than antagonizing potential local alliances who can effectively fill the institutional void in low-governance regions.

"Hominins and other mammals have co-existed since the earliest Paleolithic hunters wielding stone tools some three million years ago. Over this long timescale biodiversity losses have only recently accelerated to breakneck speeds since the industrial revolution.

"Let us make sure that this relentless wave of local extinctions is rapidly decelerated, or else the prospects for Neotropical mammals and other vertebrates will look increasingly bleak."

The team looked at 165 species and analysed local losses in more than 1000 sets of medium to large-bodied mammal species that had been surveyed across the Neotropics.

On average more than 56 per cent of the local wildlife within mammal assemblages across the Neotropics were wiped out, with ungulates lowland tapir and white-lipped peccary comprising the most losses. The extent of defaunation was widespread, but increasingly affecting relatively intact major biomes that are rapidly succumbing to encroaching deforestation frontiers.

Read more at Science Daily

Big answers from tiny particles

 A team of scientists led by Kanazawa University proposed a new mathematical framework to understand the properties of the fundamental particles called neutrinos. This work may help cosmologists make progress on the apparent paradox of the existence of matter in the Universe.

The Standard Model of particle physics that outlines the basic constituents of matter and the forces that act between them has seen remarkable experimental success, culminating in the discovery of the last predicted particle, the Higgs boson, in 2012. However, the Standard Model does not resolve some of the long-standing issues in cosmology, such as the identity of "dark matter" that we know must be there but we cannot see, and why there is so much matter in the Universe compared with antimatter. Many scientists believe that the ghost-like particles called neutrinos may be an important part of the answer.

Neutrinos, which hardly interact with other matter, are created by nuclear reactions such as those that power our sun, and trillions of them pass through your body every second. Experiments have shown that, while not massless, neutrinos are much lighter than other particles. This has led physicists to hypothesize that neutrinos get their mass from a different process compared with other particles, called the "Seesaw mechanism."

Now, a research team led by Kanazawa University has developed a new theory to explain the unusual properties of neutrinos.

"We used the seesaw mechanisms with five- or seven-dimensional operators to describe the interaction of a neutrino with two lepton particles and two force-carrying W bosons," explains Mayumi Aoki.

Leptons are a class of elementary particles that include neutrinos, electrons, and so on. Solving these equations showed violations of the Standard Model's prediction that the number of leptons is always conserved.

"To move beyond the Standard Model, we have to explain why lepton conservation is sometimes violated, albeit to a very small degree," says Aoki. "A tiny imbalance of one part in a trillion may explain the why all matter didn't get annihilated by antimatter after the Big Bang."

"Our work explains the origin of the neutrino mass and also provides predictions directly testable by the Large Hadron Collider," says Aoki. The very light masses of neutrinos might hold the key to solving the big questions that have challenged humanity for millennia.

From Science Daily

New study explores if flirting is real and shows it can work

 "She was totally flirting with you," my friend told me after the hosts left our table.

"No, she wasn't. She was just being polite," said another friend.

Misunderstandings about flirting can potentially result in awkwardness or even accusations of sexual harassment. How can we figure out what other people mean when they smile at us? Is there a unique, identifiable facial expression representing flirting -- and if there is, what does it convey, and how effective is it?

Although flirting is mentioned a lot in the general media, and examples are everywhere, there is relatively little scientific work on the topic of flirting, its underlying mechanisms and function.

Now, a new paper by researchers based at the University of Kansas has been published in the Journal of Sex Research examining if flirting has a particular facial cue effectively used by women to indicate interest in a man.

"There are very few scientific articles out there that have systematically studied this well-known phenomenon," said Omri Gillath, professor of psychology at KU, who co-wrote the paper. "None of these studies have identified the flirting facial expression and tested its effects."

Gillath's collaborators were lead author Parnia Haj-Mohamadi, a doctoral student in psychology at KU, and Erika Rosenberg of the University of California-Davis.

The researchers found internal states -- such as being romantically or sexually interested in someone -- can be conveyed to others nonverbally through facial expression.

In other words -- flirting works.

"Across our six studies, we found most men were able to recognize a certain female facial expression as representing flirting," Gillath said. "It has a unique morphology, and it's different from expressions that have similar features -- for example, smiling -- but aren't identified by men as flirting expression."

In the studies, women -- some professional actresses and some volunteers from the community -- were asked either to spontaneously pose a flirting expression (similar to what they'd use at a bar to get attention from a potential mate) or to follow instructions based on existing anthropological literature for what researchers define as flirting.

The team found some women are more effective than others in effectively conveying a flirtatious facial cue, while some men are better at recognizing this cue. Beyond these individual differences, a few expressions were identified by most (if not all) men as flirting.

The researchers used the Facial Action Coding System (FACS) to classify the morphology of highly recognized flirtatious facial expressions. The coding showed the most effective flirting cues include a head turned to one side and tilted down slightly, a slight smile, and eyes turned forward toward the implied target.

After identifying these most recognized expressions of flirting, the researchers used them in experimental studies.

"Our findings support the role of flirtatious expression in communication and mating initiation," Gillath said. "For the first time, not only were we able to isolate and identify the expressions that represent flirting, but we were also able to reveal their function -- to activate associations related with relationships and sex."

Read more at Science Daily

New dopamine sensors could help unlock the mysteries of brain chemistry

 In 2018, Lin Tian and her team at UC Davis Health developed dLight1, a single fluorescent protein-based biosensor. This family of highly specific sensors detects dopamine, a hormone released by neurons to send signals to other nerve cells. When combined with advanced microscopy, dLight1 provides high resolution, real-time imaging of the spatial and temporal release of dopamine in live animals.

Recently, Tian and her team succeeded in expanding the color spectrum of the dLight1 sensor. In an article published Sept. 7 in Nature Methods, they introduced two new spectral variants of dLight1: the yellow YdLight1 and the red RdLight1.

"The new sensors will help researchers to detect and monitor different information processing activities in the brain," said Lin Tian, associate professor of biochemistry and molecular medicine and the lead author on the study. "With the different colors, we will be able to see multiple neurochemical release and neural activities at the same time."

The RdLight1 permits the simultaneous assessment of dopamine, pre- or post-synaptic neuronal activity and the glutamate release in specific types of cells and neuronal projections in animals. Its increased light penetration and imaging depth provide enhanced dopamine signal quality. This allows researchers to optically dissect dopamine's release and model its effects on neural circuits.

As a neurotransmitter, dopamine plays an important role in movement, attention, learning and the brain's pleasure and reward system.

"These exciting new tools opened a new door to developing color-shifted neurochemical indicators. Together with other tools, they have great potential to unlock the mysteries of brain chemistry in health and disease," Tian said. "The knowledge we gain from these sensors will facilitate the development of safer next-generation therapies to neuropsychiatric disorders such as depression, anxiety, schizophrenia and addiction."

From Science Daily

New treatments for deadly lung disease could be revealed by 3D modeling

 A 3D bioengineered model of lung tissue built by University of Michigan researchers is poking holes in decades worth of flat, Petri dish observations into how the deadly disease pulmonary fibrosis progresses.

The causes of pulmonary fibrosis are not fully understood, but the condition is marked by scar tissue that forms inside the lungs. That scar tissue stiffens the walls of the lungs' air sacs, called alveoli, or, at advanced stages, can completely fill the alveolar spaces. Both scenarios make breathing difficult and decrease the amount of oxygen entering the bloodstream. Often the condition is irreversible, eventually causing lung failure and death.

Some clinicians are concerned that critically ill COVID-19 patients may develop a form of pulmonary fibrosis after a long stay in the ICU.

Researchers are searching for better treatments. While they've managed to find some drugs that relieve symptoms or slow the progression in practice, they haven't been able to reliably replicate those results in today's 2D lab models. So they don't understand how or why those drugs are working, and they can't always predict which compounds will make a difference. The new research from U-M takes a step in that direction, and it starkly demonstrates how prior approaches have been ineffective.

The team showed that in some 2D models, drugs that are already known to be effective in treatment do not produce test results that show efficacy. Their 3D tissue engineered model of fibrotic lung tissue, however, shows that those drugs work.

Before their tests on drugs, they first performed studies to understand how tissue stiffness drives the appearance of myofibroblasts -- cells that correlate with the progression of scarring.

"Even in cells from the same patient, we saw different outcomes," said Daniel Matera, a doctoral candidate and research team member. "When we introduced stiffness into the 2D testing environment, it activated myofibroblasts, essentially creating scar tissue. When we introduced that same kind of stiffness into our 3D testing environment, it prevented or slowed the activation of myofibroblasts, stopping or slowing the creation of scar tissue."

With the majority of pulmonary fibrosis research relying on 2D testing, he said, many have believed the high lung stiffness in patients is what should be targeted by treatments. U-M's research indicates that targeting stiffness alone may not hinder disease progression in patients, even if it works in a Petri dish.

To find effective treatments, researchers first screen libraries of pharmaceutical compounds. Today, they typically do that on cells cultured on flat plastic or hydrogel surfaces, but these settings often do a poor job of recreating what happens in the human body.

Brendon Baker, assistant professor in the U-M Department of Biomedical Engineering, and his team took a tissue engineering approach. They reconstructed 3D lung interstitium, or connective tissue, the home of fibroblasts and location where fibrosis begins. Their goal was to understand how mechanical cues from lung tissue affect fibroblast behavior and disease progression.

"Recreating the 3D fibrous structure of the lung interstitium allowed us to confirm effective drugs that wouldn't be identified as hits in traditional screening settings," Baker said.

At the center of the pulmonary fibrosis mystery is the fibroblast, a cell found in the lung interstitium that is crucial to healing but, paradoxically, can also drive disease progression. When activated, after an injury or when disease is present, they become myofibroblasts. Regulated properly, they play an important role in wound healing, but when misregulated, they can drive chronic disease. In the case of pulmonary fibrosis, they cause the stiffening of lung tissue that hampers breathing.

"Our lung tissue model looks and behaves similarly to what we have observed when imaging real lung tissue," Baker said. "Patient cells within our model can actively stiffen, degrade or remodel their own environment just like they do in disease."

 Read more at Science Daily

Dams exacerbate the consequences of climate change on river fish

 A potential response of river fish to environmental changes is to colonize new habitats. But what happens when dams and weirs restrict their movement? And are native and alien species similarly affected? Researchers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) and the Spanish University of Girona (UdG) have addressed these questions in a recent study.

River ecosystems are frequently fragmented by dams and weirs. As a result, native fish are often restricted in their movement along the river course and are unable to colonize new habitats. Thus, barriers impede native species from adjusting their distributions in response to the effects of climate change such as changes in water temperature and quality.

On the other hand, river fragmentation might also limit the further spread of invasive alien species. Using the Ebro River in Spain as an example, the research team has investigated how habitats of native and alien fish species change under different climate scenarios and how dams mediate habitat accessibility.

"The Ebro River is particularly vulnerable and threatened by climate change and species invasions. In addition, the Ebro River is fragmented by over 300 dams and many smaller barriers, which makes it even worse for the native fish species," said Emili García-Berthou, Professor at the University of Girona and co-author of the study.

By applying a spatial modelling framework, the authors showed that losses of native species and gains of alien species and consequentially most pronounced biodiversity changes are particularly expected in the lower and mid reaches of larger Ebro River tributaries. According to their results, the majority of species are projected to shift their range in upstream direction with alien species such as eastern mosquitofish, wels catfish and common carp showing especially large habitat gains.

"The Ebro River system is home to several endemic species that exclusively occur on the Iberian Peninsula. These species are particularly imperilled by barriers that limit movements in response to climate change. Whether dams can effectively prevent the spread of alien species is questionable. In fact, the establishment of alien fishes is often facilitated by the changed flow and habitat conditions that result from damming rivers," said IGB researcher Johannes Radinger, lead author of the study.

Read more at Science Daily

A warm Jupiter orbiting a cool star

 A planet observed crossing in front of, or transiting, a low-mass star has been determined to be about the size of Jupiter. While hundreds of Jupiter-sized planets have been discovered orbiting larger sun-like stars, it is rare to see these planets orbiting low-mass host stars and the discovery could help astronomers to better understand how these giant planets form.

"This is only the fifth Jupiter-sized planet transiting a low-mass star that has been observed and the first with such a long orbital period, which makes this discovery really exciting," said Caleb Cañas, lead author of the paper and a Ph.D. student at Penn State and NASA Earth and Space Science Fellow.

Originally detected by NASA's Transiting Exoplanet Survey Satellite (TESS) spacecraft, astronomers characterized the planet's mass, radius, and its orbital period using the Habitable-zone Planet Finder (HPF), an astronomical spectrograph built by a Penn State team and installed on the 10m Hobby-Eberly Telescope at McDonald Observatory in Texas. A paper describing the research appears in the September 2020 issue of the Astronomical Journal and is publicly accessible on arXiv.

"A transiting Jupiter-sized planet is amenable to further observations to see how well the orbit is aligned with the spin-axis of the host star and to constrain how it could have formed," said Cañas. "Furthermore, the low mass of the host star and the long orbital period result in a Jupiter with a moderate temperature compared to similar planets detected with NASA's Kepler space telescope."

The host star, TOI-1899, is a low-mass (M dwarf) star about 419 light years away from Earth. The planet, TOI-1899 b, is two-thirds the mass of Jupiter, ten percent larger in radius than Jupiter, and is 0.16 astronomical units (AU) -- a measure defined as the distance between the Earth and the sun -- from its host star such that a full year on TOI-1899 takes only 29 Earth days. For comparison, the four other transiting Jupiter-size planets around comparable stars complete their orbits in less than 4 days.

The planet was detected by TESS using the transit method, which searches for stars showing periodic dips in their brightness as a telltale sign of an orbiting object crossing in front of the star and blocking a portion of its light. The signal was later confirmed as a planet using precision observations from the HPF spectrograph that measure the planet's mass by analyzing how it causes its host start to the wobble.

From a formation and orbital evolution perspective, there is not a clear dividing line between warm Jupiters and the large planets even closer to their host stars, the more commonly discovered hot Jupiters.

"Warm Jupiters like TOI-1899 b orbit surprisingly close to their star," said Rebekah Dawson, assistant professor of astronomy and astrophysics at Penn State and an author of the paper. "Even though the planet's orbital period is long compared to many other giant planets detected and characterized through the transit method, it still places the giant planet much closer to its star than we'd expect from classical formation theories. Detailed characterization of their physical and orbital properties, system architecture, and host stars -- as the HPF team has done for TOI-1899 b -- allow us test theories for how giant planets can form or be displaced so close to their star."

The Habitable-zone Planet Finder was delivered to the 10m Hobby Eberly Telescope at McDonald Observatory in late 2017, and started full science operations in late 2018. HPF is designed to detect and characterize planets in the Habitable-zone -- the region around the star where a planet could sustain liquid water on its surface -- around nearby M-dwarf stars, but is also capable of making sensitive measurements for planets outside the habitable zone.

"This warm Jupiter is a compelling target for atmospheric characterization with upcoming missions like the James Webb Space Telescope," said Suvrath Mahadevan, professor of astronomy and astrophysics at Penn State, the principal investigator of the HPF spectrograph, and an author of the paper. "HPF was critical in helping us to confirm this, but detecting a second transit is important to very precisely pin down its period."

Read more at Science Daily

Possible marker of life spotted on venus

 

Planet Venus

An international team of astronomers today announced the discovery of a rare molecule -- phosphine -- in the clouds of Venus. On Earth, this gas is only made industrially or by microbes that thrive in oxygen-free environments. Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes -- floating free of the scorching surface but needing to tolerate very high acidity. The detection of phosphine could point to such extra-terrestrial 'aerial' life.

"When we got the first hints of phosphine in Venus's spectrum, it was a shock!," says team leader Jane Greaves of Cardiff University in the UK, who first spotted signs of phosphine in observations from the James Clerk Maxwell Telescope (JCMT), operated by the East Asian Observatory, in Hawai'i. Confirming their discovery required using 45 antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, a more sensitive telescope in which the European Southern Observatory (ESO) is a partner. Both facilities observed Venus at a wavelength of about 1 millimetre, much longer than the human eye can see -- only telescopes at high altitude can detect it effectively.

The international team, which includes researchers from the UK, US and Japan, estimates that phosphine exists in Venus's clouds at a small concentration, only about twenty molecules in every billion. Following their observations, they ran calculations to see whether these amounts could come from natural non-biological processes on the planet. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. These non-biological sources were found to make at most one ten thousandth of the amount of phosphine that the telescopes saw.

To create the observed quantity of phosphine (which consists of hydrogen and phosphorus) on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity, according to the team. Earth bacteria are known to make phosphine: they take up phosphate from minerals or biological material, add hydrogen, and ultimately expel phosphine. Any organisms on Venus will probably be very different to their Earth cousins, but they too could be the source of phosphine in the atmosphere.

While the discovery of phosphine in Venus's clouds came as a surprise, the researchers are confident in their detection. "To our great relief, the conditions were good at ALMA for follow-up observations while Venus was at a suitable angle to Earth. Processing the data was tricky, though, as ALMA isn't usually looking for very subtle effects in very bright objects like Venus," says team member Anita Richards of the UK ALMA Regional Centre and the University of Manchester. "In the end, we found that both observatories had seen the same thing -- faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below," adds Greaves, who led the study published today in Nature Astronomy.

Another team member, Clara Sousa Silva of the Massachusetts Institute of Technology in the US, has investigated phosphine as a "biosignature" gas of non-oxygen-using life on planets around other stars, because normal chemistry makes so little of it. She comments: "Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment -- but the clouds of Venus are almost entirely made of acid."

The team believes their discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of "life" needs a lot more work. Although the high clouds of Venus have temperatures up to a pleasant 30 degrees Celsius, they are incredibly acidic -- around 90% sulphuric acid -- posing major issues for any microbes trying to survive there.

ESO astronomer and ALMA European Operations Manager Leonardo Testi, who did not participate in the new study, says: "The non-biological production of phosphine on Venus is excluded by our current understanding of phosphine chemistry in rocky planets' atmospheres. Confirming the existence of life on Venus's atmosphere would be a major breakthrough for astrobiology; thus, it is essential to follow-up on this exciting result with theoretical and observational studies to exclude the possibility that phosphine on rocky planets may also have a chemical origin different than on Earth."

More observations of Venus and of rocky planets outside our Solar System, including with ESO's forthcoming Extremely Large Telescope, may help gather clues on how phosphine can originate on them and contribute to the search for signs of life beyond Earth.

Read more at Science Daily

Carbon-rich exoplanets may be made of diamonds

 As missions like NASA's Hubble Space Telescope, TESS and Kepler continue to provide insights into the properties of exoplanets (planets around other stars), scientists are increasingly able to piece together what these planets look like, what they are made of, and if they could be habitable or even inhabited.

In a new study published recently in The Planetary Science Journal, a team of researchers from Arizona State University (ASU) and the University of Chicago have determined that some carbon-rich exoplanets, given the right circumstances, could be made of diamonds and silica.

"These exoplanets are unlike anything in our solar system," says lead author Harrison Allen-Sutter of ASU's School of Earth and Space Exploration.

Diamond exoplanet formation

When stars and planets are formed, they do so from the same cloud of gas, so their bulk compositions are similar. A star with a lower carbon to oxygen ratio will have planets like Earth, comprised of silicates and oxides with a very small diamond content (Earth's diamond content is about 0.001%).

But exoplanets around stars with a higher carbon to oxygen ratio than our sun are more likely to be carbon-rich. Allen-Sutter and co-authors Emily Garhart, Kurt Leinenweber and Dan Shim of ASU, with Vitali Prakapenka and Eran Greenberg of the University of Chicago, hypothesized that these carbon-rich exoplanets could convert to diamond and silicate, if water (which is abundant in the universe) were present, creating a diamond-rich composition.

Diamond-anvils and X-rays

To test this hypothesis, the research team needed to mimic the interior of carbide exoplanets using high heat and high pressure. To do so, they used high pressure diamond-anvil cells at co-author Shim's Lab for Earth and Planetary Materials.

First, they immersed silicon carbide in water and compressed the sample between diamonds to a very high pressure. Then, to monitor the reaction between silicon carbide and water, they conducted laser heating at the Argonne National Laboratory in Illinois, taking X-ray measurements while the laser heated the sample at high pressures.

As they predicted, with high heat and pressure, the silicon carbide reacted with water and turned into diamonds and silica.

Habitability and inhabitability

So far, we have not found life on other planets, but the search continues. Planetary scientists and astrobiologists are using sophisticated instruments in space and on Earth to find planets with the right properties and the right location around their stars where life could exist.

For carbon-rich planets that are the focus of this study, however, they likely do not have the properties needed for life.

While Earth is geologically active (an indicator habitability), the results of this study show that carbon-rich planets are too hard to be geologically active and this lack of geologic activity may make atmospheric composition uninhabitable. Atmospheres are critical for life as it provides us with air to breathe, protection from the harsh environment of space, and even pressure to allow for liquid water.

Read more at Science Daily

How coronavirus took hold in North America and in Europe

 

Global spread of coronavirus, concept illustration

A new study combines evolutionary genomics from coronavirus samples with computer-simulated epidemics and detailed travel records to reconstruct the spread of coronavirus across the world in unprecedented detail.

Published in the journal Science, the results suggest an extended period of missed opportunity when intensive testing and contact tracing might have prevented SARS-CoV-2 from becoming established in North America and Europe.

The paper also challenges suggestions that linked the earliest known cases of COVID-19 on each continent in January to outbreaks detected weeks later, and provides valuable insights that could inform public health response and help with anticipating and preventing future outbreaks of COVID-19 and other zoonotic diseases.

"Our aspiration was to develop and apply powerful new technology to conduct a definitive analysis of how the pandemic unfolded in space and time, across the globe," said University of Arizona researcher Michael Worobey, who led an interdisciplinary team of scientists from 13 research institutions in the U.S., Belgium, Canada and the U.K. "Before, there were lots of possibilities floating around in a mish-mash of science, social media and an unprecedented number of preprint publications still awaiting peer review."

The team based their analysis on results from viral genome sequencing efforts, which began immediately after the virus was identified. These efforts quickly grew into a worldwide effort unprecedented in scale and pace and have yielded tens of thousands of genome sequences, publicly available in databases.

Contrary to widespread narratives, the first documented arrivals of infected individuals traveling from China to the U.S. and Europe did not snowball into continental outbreaks, the researchers found.

Instead, swift and decisive measures aimed at tracing and containing those initial incursions of the virus were successful and should serve as model responses directing future actions and policies by governments and public health agencies, the study's authors conclude.

How the Virus Arrived in the U.S. and Europe

A Chinese national flying into Seattle from Wuhan, China on Jan. 15 became the first patient in the U.S. shown to be infected with the novel coronavirus and the first to have a SARS-CoV-2 genome sequenced. This patient was designated 'WA1.' It was not until six weeks later that several additional cases were detected in Washington state.

"And while all that time goes past, everyone is in the dark and wondering, 'What's happening?'" Worobey said. "We hope we're OK, we hope there are no other cases, and then it becomes clear, from a remarkable community viral sampling program in Seattle, that there are more cases in Washington and they are genetically very similar to WA1's virus."

Worobey and his collaborators tested the prevailing hypothesis suggesting that patient WA1 had established a transmission cluster that went undetected for six weeks. Although the genomes sampled in February and March share similarities with WA1, they are different enough that the idea of WA1 establishing the ensuing outbreak is very unlikely, they determined. The researchers' findings indicate that the jump from China to the U.S. likely occurred on or around Feb. 1 instead.

The results also puts to rest speculation that this outbreak, the earliest substantial transmission cluster in the U.S., may have been initiated indirectly by dispersal of the virus from China to British Columbia, Canada, just north of Washington State, and then spread from Canada to the U.S. Multiple SARS-CoV-2 genomes published by the British Columbia Center for Disease Control appeared to be ancestral to the viral variants sampled in Washington State, strongly suggesting a Canadian origin of the U.S. epidemic. However, the present study revealed sequencing errors in those genomes, thus ruling out this scenario.

Instead, the new study implicates a direct-from-China source of the U.S. outbreak, right around the time the U.S. administration implemented a travel ban for travelers from China in early February. The nationality of the "index case" of the U.S. outbreak cannot be known for certain because tens of thousands of U.S. citizens and visa holders traveled from China to the U.S. even after the ban took effect.

A similar scenario marks the first known introduction of coronavirus into Europe. On Jan. 20, an employee of an automotive supply company in Bavaria, Germany, flew in for a business meeting from Shanghai, China, unknowingly carrying the virus, ultimately leading to infection of 16 co-workers. In that case, too, an impressive response of rapid testing and isolation prevented the outbreak from spreading any further, the study concludes. Contrary to speculation, this German outbreak was not the source of the outbreak in Northern Italy that eventually spread widely across Europe and eventually to New York City and the rest of the U.S.

The authors also show that this China-to-Italy-US dispersal route ignited transmission clusters on the East Coast slightly later in February than the China-to-US movement of the virus that established the Washington State outbreak. The Washington transmission cluster also predated small clusters of community transmission in February in California, making it the earliest anywhere in North America.

Early Containment Works

The authors say intensive interventions, involving testing, contact tracing, isolation measures and a high degree of compliance of infected individuals, who reported their symptoms to health authorities and self-isolated in a timely manner, helped Germany and the Seattle area contain those outbreaks in January.

"We believe that those measures resulted in a situation where the first sparks could successfully be stamped out, preventing further spread into the community," Worobey said. "What this tells us is that the measures taken in those cases are highly effective and should serve as a blueprint for future responses to emerging diseases that have the potential to escalate into worldwide pandemics."

To reconstruct the pandemic's unfolding, the scientists ran computer programs that carefully simulated the epidemiology and evolution of the virus, in other words, how SARS-CoV-2 spread and mutated over time.

"This allowed us to re-run the tape of how the epidemic unfolded, over and over again, and then check the scenarios that emerge in the simulations against the patterns we see in reality," Worobey said.

"In the Washington case, we can ask, 'What if that patient WA1 who arrived in the U.S. on Jan. 15 really did start that outbreak?' Well, if he did, and you re-run that epidemic over and over and over, and then sample infected patients from that epidemic and evolve the virus in that way, do you get a pattern that looks like what we see in reality? And the answer was no," he said.

"If you seed that early Italian outbreak with the one in Germany, do you see the pattern that you get in the evolutionary data? And the answer, again, is no," he said.

"By re-running the introduction of SARS-CoV-2 into the U.S. and Europe through simulations, we showed that it was very unlikely that the first documented viral introductions into these locales led to productive transmission clusters," said co-author Joel Wertheim of the University of California, San Diego. "Molecular epidemiological analyses are incredibly powerful for revealing transmissions patterns of SARS-CoV-2."

Other methods were then combined with the data from the virtual epidemics, yielding exceptionally detailed and quantitative results.

"Fundamental to this work stands our new tool combining detailed travel history information and phylogenetics, which produces a sort of 'family tree' of how the different genomes of virus sampled from infected individuals are related to each other," said co-author Marc Suchard of the University of California, Los Angeles. "The more accurate evolutionary reconstructions from these tools provide a critical step to understand how SARS-CoV-2 spread globally in such a short time."

"We have to keep in mind that we have studied only short-term evolution of this virus, so it hasn't had much time to accumulate many mutations," said co-author Philippe Lemey of the University of Leuven, Belgium. "Add to that the uneven sampling of genomes from different parts of the world, and it becomes clear that there are huge benefits to be gained from integrating various sources of information, combining genomic reconstructions with complementary approaches like flight records and the total number of COVID-19 cases in various global regions in January and February."

Read more at Science Daily