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  • TRAPPIST-1 planets provide clues to the nature of habitable worlds
    21.03.2018 02:09:10
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    TRAPPIST-1 planets provide clues to the nature of habitable worlds Tempe AZ (SPX) Mar 21, 2018 -
    TRAPPIST-1 is an ultra-cool red dwarf star that is slightly larger, but much more massive, than the planet Jupiter, located about 40 light-years from the Sun in the constellation Aquarius.Among planetary systems, TRAPPIST-1 is of particular interest because seven planets have been detected orbiting this star, a larger number of planets than have been than detected in any other exoplanetary system. In addition, all of the TRAPPIST-1 planets are Earth-sized and terrestrial, making them an ideal focus of study for planet formation and potential habitability.ASU scientists Cayman Unterborn, Steven Desch, and Alejandro Lorenzo of the School of Earth and Space Exploration, with Natalie Hinkel of Vanderbilt University, have been studying these planets for habitability, specifically related to water composition. Their findings have been recently published in Nature Astronomy.Water on the TRAPPIST-1 Planets
    The TRAPPIST-1 planets are curiously light. From their measured mass and volume, all of this system's planets are less dense than rock. On many other, similarly low-density worlds, it is thought that this less-dense component consists of atmospheric gasses."But the TRAPPIST-1 planets are too small in mass to hold onto enough gas to make up the density deficit," explains geoscientist Unterborn. "Even if they were able to hold onto the gas, the amount needed to make up the density deficit would make the planet much puffier than we see."So scientists studying this planetary system have determined that the low-density component must be something else that is abundant: water. This has been predicted before, and possibly even seen on larger planets like GJ1214b, so the interdisciplinary ASU-Vanderbilt team, comprised of geoscientists and astrophysicists, set out to determine just how much water could be present on these Earth-sized planets and how and where the planets may have formed.Calculating water amounts on TRAPPIST-1 planets
    To determine the composition of the TRAPPIST-1 planets, the team used a unique software package, developed by Unterborn and Lorenzo, that uses state-of-the-art mineral physics calculators. The software, called ExoPlex, allowed the team to combine all of the available information about the TRAPPIST-1 system, including the chemical makeup of the star, rather than being limited to just the mass and radius of individual planets.Much of the data used by the team to determine composition was collected from a dataset called the Hypatia Catalog, developed by contributing author Hinkel. This catalog merges data on the stellar abundances of stars near to our Sun, from over 150 literature sources, into a massive repository.What they found through their analyses was that the relatively "dry" inner planets (labeled "b" and "c" on this image) were consistent with having less than 15 percent water by mass (for comparison, Earth is 0.02 percent water by mass). The outer planets (labeled "f" and "g" on this image) were consistent with having more than 50 percent water by mass. This equates to the water of hundreds of Earth-oceans. The masses of the TRAPPIST-1 planets continue to be refined, so these proportions must be considered estimates for now, but the general trends seem clear."What we are seeing for the first time are Earth-sized planets that have a lot of water or ice on them," says ASU astrophysicist and contributing author, Steven Desch.But the researchers also found that the ice-rich TRAPPIST-1 planets are much closer to their host star than the ice line. The "ice line" in any solar system, including TRAPPIST-1's, is the distance from the star beyond which water exists as ice and can be accreted into a planet; inside the ice line water exists as vapor and will not be accreted. Through their analyses, the team determined that the TRAPPIST-1 planets must have formed much farther from their star, beyond the ice line, and migrated in to their current orbits close to the host star.There are many clues that planets in this system and others have undergone substantial inward migration, but this study is the first to use composition to bolster the case for migration. What's more, knowing which planets formed inside and outside of the ice line allowed the team to quantify for the first time how much migration took place.Because stars like TRAPPIST-1 are brightest right after they form and gradually dim thereafter, the ice line tends to move in over time, like the boundary between dry ground and snow-covered ground around a dying campfire on a snowy night. The exact distances the planets migrated inward depends on when they formed. "The earlier the planets formed," says Desch, "the further away from the star they needed to have formed to have so much ice." But for reasonable assumptions about how long planets take to form, the TRAPPIST-1 planets must have migrated inward from at least twice as far away as they are now.Too much of a good thing
    Interestingly, while we think of water as vital for life, the TRAPPIST-1 planets may have too much water to support life."We typically think having liquid water on a planet as a way to start life, since life, as we know it on Earth, is composed mostly of water and requires it to live," explains Hinkel. "However, a planet that is a water world, or one that doesn't have any surface above the water, does not have the important geochemical or elemental cycles that are absolutely necessary for life."Ultimately, this means that while M-dwarf stars, like TRAPPIST-1, are the most common stars in the universe (and while it's likely that there are planets orbiting these stars), the huge amount of water they are likely to have makes them unfavorable for life to exist, especially enough life to create a detectable signal in the atmosphere that can be observed. "It's a classic scenario of 'too much of a good thing,'" says Hinkel.So, while we're unlikely to find evidence of life on the TRAPPIST-1 planets, through this research we may gain a better understanding of how icy planets form and what kinds of stars and planets we should be looking for in our continued search for life.Research paper
  • ESA's next science mission to focus on nature of exoplanets
    21.03.2018 02:09:10
    ESA's next science mission to focus on nature of exoplanets Paris (ESA) Mar 21, 2018 -
    The nature of planets orbiting stars in other systems will be the focus for ESA's fourth medium-class science mission, to be launched in mid 2028.ARIEL, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey mission, was selected by ESA as part of its Cosmic Vision plan.The mission addresses one of the key themes of Cosmic Vision: What are the conditions for planet formation and the emergence of life?Thousands of exoplanets have already been discovered with a huge range of masses, sizes and orbits, but there is no apparent pattern linking these characteristics to the nature of the parent star. In particular, there is a gap in our knowledge of how the planet's chemistry is linked to the environment where it formed, or whether the type of host star drives the physics and chemistry of the planet's evolution.ARIEL will address fundamental questions on what exoplanets are made of and how planetary systems form and evolve by investigating the atmospheres of hundreds of planets orbiting different types of stars, enabling the diversity of properties of both individual planets as well as within populations to be assessed.Observations of these worlds will give insights into the early stages of planetary and atmospheric formation, and their subsequent evolution, in turn contributing to put our own Solar System in context."ARIEL is a logical next step in exoplanet science, allowing us to progress on key science questions regarding their formation and evolution, while also helping us to understand Earth's place in the Universe," says Gunther Hasinger, ESA Director of Science."ARIEL will allow European scientists to maintain competitiveness in this dynamic field. It will build on the experiences and knowledge gained from previous exoplanet missions."The mission will focus on warm and hot planets, ranging from super-Earths to gas giants orbiting close to their parent stars, taking advantage of their well-mixed atmospheres to decipher their bulk composition.ARIEL will measure the chemical fingerprints of the atmospheres as the planet crosses in front of its host star, observing the amount of dimming at a precision level of 10-100 parts per million relative to the star.As well as detecting signs of well-known ingredients such as water vapour, carbon dioxide and methane, it will also be able to measure more exotic metallic compounds, putting the planet in context of the chemical environment of the host star.For a select number of planets, ARIEL will also perform a deep survey of their cloud systems and study seasonal and daily atmospheric variations.ARIEL's metre-class telescope will operate at visible and infrared wavelengths. It will be launched on ESA's new Ariane 6 rocket from Europe's spaceport in Kourou in mid 2028. It will operate from an orbit around the second Lagrange point, L2, 1.5 million kilometres directly 'behind' Earth as viewed from the Sun, on an initial four-year mission.Following its selection by ESA's Science Programme Committee, the mission will continue into another round of detailed mission study to define the satellite's design. This would lead to the 'adoption' of the mission - presently planned for 2020 - following which an industrial contractor will be selected to build it.ARIEL was chosen from three candidates, competing against the space plasma physics mission THOR (Turbulence Heating ObserveR) and the high-energy astrophysics mission XIPE (X-ray Imaging Polarimetry Explorer).Solar Orbiter, Euclid and PLATO have already been selected as medium-class missions.
  • 'Oumuamua likely came from a binary star system
    21.03.2018 02:09:10
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    'Oumuamua likely came from a binary star system London, UK (SPX) Mar 20, 2018 -
    New research finds that 'Oumuamua, the rocky object identified as the first confirmed interstellar asteroid, very likely came from a binary star system."It's remarkable that we've now seen for the first time a physical object from outside our Solar System," says lead author Dr Alan Jackson, a postdoc at the Centre for Planetary Sciences at the University of Toronto Scarborough in Ontario, Canada.A binary star system, unlike our Sun, is one with two stars orbiting a common centre.For the new study, published in the journal Monthly Notices of the Royal Astronomical Society, Jackson and his co-authors set about testing how efficient binary star systems are at ejecting objects. They also looked at how common these star systems are in the Galaxy.They found that rocky objects like 'Oumuamua are far more likely to come from binary than single star systems. They were also able to determine that rocky objects are ejected from binary systems in comparable numbers to icy objects."It's really odd that the first object we would see from outside our system would be an asteroid, because a comet would be a lot easier to spot and the Solar System ejects many more comets than asteroids," says Jackson, who specializes in planet and solar system formation.Once they determined that binary systems are very efficient at ejecting rocky objects, and that a sufficient number of them exist, they were satisfied that 'Oumuamua very likely came from a binary system. They also concluded that it probably came from a system with a relatively hot, high mass star since such a system would have a greater number of rocky objects closer in.The team suggest that the asteroid was very likely to have been ejected from its binary system sometime during the formation of planets.'Oumuamua, which is Hawaiian for 'scout', was first spotted by the Haleakala Observatory in Hawaii on 19 October 2017. With a radius of 200 metres and travelling at a blistering speed of 30 kilometres per second, at its closest it was about 33,000,000 km from Earth.When it was first discovered researchers initially assumed the object was a comet, one of countless icy objects that release gas when they warm up on approaching the Sun. But it didn't show any comet-like activity as it neared the Sun, and was quickly reclassified as an asteroid, meaning it was rocky.Researchers were also fairly sure it was from outside our Solar System, based on its trajectory and speed. An eccentricity of 1.2 - which classifies its path as an open-ended hyperbolic orbit - and such a high speed meant it was not bound by the gravity of the Sun.In fact, as Jackson points out, 'Oumuamua's orbit has the highest eccentricity ever observed in an object passing through our Solar System.Major questions about 'Oumuamua remain. For planetary scientists like Jackson, being able to observe objects like these may yield important clues about how planet formation works in other star systems."The same way we use comets to better understand planet formation in our own Solar System, maybe this curious object can tell us more about how planets form in other systems."Research paper
  • UK team to lead European mission to study new planets
    21.03.2018 02:09:10
    UK team to lead European mission to study new planets London, UK (SPX) Mar 21, 2018 -
    The ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) mission was selected as the next European Space Agency (ESA) science mission, putting UK leadership at the heart of research into planets that lie outside our solar system - exoplanets.Thousands of exoplanets have now been discovered with a huge diversity of masses, sizes and orbits, but very little is known about their chemical composition, formation, or their evolutionary links to their host stars.ARIEL will carry out the first ever large-scale survey of exoplanets specifically to examine their atmospheres. It will study hot, Jupiter-size planets close to their stars, and so will help scientists understand the key processes which form planetary systems and affect how they evolve.Science Minister Sam Gyimah said: "Space is our final frontier and, working with UCL, we want to be at the forefront of discovering new planets. British involvement in this incredibly exciting new mission demonstrates how integral our world-leading scientific expertise is in solving some of space's greatest mysteries."The UK is a go-to destination for research and discovery, being home to some of the brightest and best talent. Through our modern Industrial Strategy and record funding for R and D, increasing investment to around Pounds 12 billion by 2021, we will continue to do all we can to boost our world-leading science sector and build a Britain fit for the future."ESA's Science Programme Committee chose ARIEL for the fourth medium class science mission (M4) in its Cosmic Vision Programme. Subject to further review, the UK Space Agency will provide a multi-million pound investment package to support UK leadership of the project.Dr. Graham Turnock, Chief Executive of the UK Space Agency, said: "It is thanks to the world-leading skills of our innovative space community that a UK-led consortium has been chosen to take forward the next ESA science mission. This demonstrates what a vital role we continue to play in European collaboration on research in space."The ARIEL mission is a prime example of the scientific innovation underpinning the wider economy. It relies on the UK's science and engineering expertise, which are at the forefront of the Government's Industrial Strategy."The mission's Principal Investigator is Professor Giovanna Tinetti, from University College London, who will lead the mission science. STFC RAL Space will manage the overall European consortium building the payload, which will be assembled and tested in Harwell, Oxfordshire. Other UK involvement will come from Cardiff University, Oxford University and the UK Astronomy Technology Centre. UK industry can also expect to be involved in the satellite's construction and operations.Prof. Giovanna Tinetti of UCL said: "Although we've now discovered around 3,800 planets orbiting other stars, the nature of these exoplanets remains largely mysterious. ARIEL will study a statistically large sample of exoplanets to give us a truly representative picture of what these planets are like. This will enable us to answer questions about how the chemistry of a planet links to the environment in which it forms, and how its birth and evolution are affected by its parent star."The ARIEL Consortium Project Manager, Paul Eccleston, of STFC RAL Space, said:"It is wonderful news that ESA have selected ARIEL for the next medium class science mission. The team are very excited to have the opportunity to realise the mission we've been developing for the last two years. ARIEL will revolutionise our understanding of how planetary systems form and evolve, helping us put our own solar system into context and compare it to our neighbours in the galaxy."The UK's central roles in ARIEL build on our international leadership in astronomy and planetary science, and will complement the science being delivered by the European Space Agency's Gaia and PLATO missions, and by the NASA-led James Webb Space Telescope, all missions with major UK involvement.
  • Team discovers that wind moves microinvertebrates across desert
    21.03.2018 02:09:10
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    Team discovers that wind moves microinvertebrates across desert El Paso TX (SPX) Mar 19, 2018 -
    The work of faculty and students from The University of Texas at El Paso (UTEP) has yielded the first evidence of how waterborne microinvertebrates move across vast expanses of arid desert.An article published March 13, 2018 in Limnology and Oceanography Letters, a publication of the Association for the Sciences of Limnology and Oceanography, details for the first time how high desert winds disperse small invertebrates and how they colonize hydrologically disconnected basins throughout the region."These novel findings might have large implications for freshwater systems," said Elizabeth J. Walsh, Ph.D., professor in UTEP's Department of Biological Sciences and director of the doctoral program in Ecology and Evolutionary Biology. "As climate changes and water patterns shift, our work might help others understand the intricacies of the wind-aided dispersal of freshwater organisms. It's important because these organisms are the base of the food web. How they move will affect the movement of the biological communities that are built up around them."Walsh added that the impetus for the research grew out of a previous five-year study of Chihuahuan Desert aquatic environments funded by the National Science Foundation. Part of that project involved characterizing the biodiversity of microinvertebrates at 300 sites. Researchers wanted to better understand how organisms were colonizing these bodies of water that were separated by vast distances of desert and not tied together by hydrological links such as drainage routes."If they weren't being moved by water, and they weren't being moved by other animals, then the next thing we thought is, 'It has to be the wind,'" Walsh said.Enter Thomas E. Gill, Ph.D., UTEP professor in the Department of Geological Sciences and Environmental Science and Engineering Program, who while conducting concurrent studies on Chihuahuan Desert wind storms, pondered, "What kinds of living things are being carried along with the dust?"What followed was a multi-year interdisciplinary research effort that collected dust samples; confirming those samples contained microinvertebrates in dormant, developmental stages; rehydrating them in laboratory settings; and utilizing next-generation sequencing to determine which organisms were present in the dust.The last step involved moving the dust through a simulated storm to determine if the organisms could survive being blasted through the air across lengthy distances. Doctoral student Jose A. Rivas Jr. and Gill worked with Scott Van Pelt, Ph.D., a soil science researcher with the U.S. Department of Agriculture, to conduct such a test at the USDA Agricultural Research Service's wind tunnel facility in Big Spring, Texas."We basically simulated a wind storm," Gill said. "We took the clean desert soil, in which we mixed microinvertebrates, and blew it into the air. After this energetic, turbulent journey through the wind tunnel, our team showed that those organisms, which are about the size of grains of sand in their dormant stage in their development, survived getting sandblasted into the air. They can fly through the atmosphere, maybe hundreds of miles in viable conditions, and still wake up."Gill said the group's findings will help inspire further research on the movement of organisms. He added that the effort that took place at UTEP was a successful collaboration because of support from the UTEP Interdisciplinary Research (IDR) program, the National Institutes of Health, the National Science Foundation and the National Oceanic and Atmospheric Administration Center for Atmospheric Sciences (NCAS). He also said the work conducted by doctoral students Rivas and Jon Mohl - who served as the study's lead and second authors - was vital to the effort."It's a very exciting and unique project," said Rivas, who was the study's lead author. "Dust storms are a huge part of the Southwest. We interact with them every spring. What's interesting is not only learning about dust storms but finding out what exactly is being transported, what's in the dust? This is especially important in understanding the diversity of our Chihuahuan Desert ecosystem. Learning how small, aquatic animals are transported and colonize new areas will lead to insights into how communities in temResearch paper
  • Yale's Expres Instrument ready to find the next Earth Analog
    21.03.2018 02:09:10
    Yale's Expres Instrument ready to find the next Earth Analog New Haven, CT (SPX) Mar 14, 2018 -
    A new, ground-based spectrometer designed and built at Yale represents the most powerful step yet in the effort to identify Earth-sized planets in neighboring solar systems.The new instrument, the Extreme Precision Spectrometer (EXPRES), is now operational and collecting data at the Lowell Observatory Discovery Channel Telescope in Arizona. EXPRES will improve measurement precision by a factor of 10, enabling the detection of small, rocky planets around nearby stars."Up until now, the only planets we could detect with ground-based spectrographs were the bigger ones, the Saturns and Jupiters," said Yale professor Debra Fischer, whose team designed EXPRES."We know the smaller planets are out there, but they've slipped through our nets."Better data is particularly important, Fischer noted, because although astronomers have identified thousands of new planets in the past few years, none are analogs of Earth.Understanding which planets are similar in size to Earth and orbiting at distances from their host stars where water is likely to pool into lakes or oceans will be essential in the search for life elsewhere in the cosmos, she added.Fischer announced initial details about the installation of EXPRES at the 2018 annual meeting of the American Association for the Advancement of Science in Austin, Texas."The future trajectory of exoplanet research depends critically on how well we improve radial velocity precision in spectrometers today," Fischer said.Spectrometers are instruments astronomers use to study light that is emitted by planets, stars, and galaxies. They are used in tandem with either a ground-based or orbital telescope.Spectrometers stretch out a beam of light into a spectrum of frequencies - which is then analyzed to determine an object's speed, direction, chemical composition, or mass. The gravity of a star holds a planet in its orbit, but the planet also tugs on the star. Radial velocity refers to the motion of the star along our line of sight.The challenge for astronomers has been designing spectrometers with enough stability and fidelity to measure tiny wobbles from Earth-like planets. For EXPRES, Fischer worked with Jessi Cisewski, an assistant professor of statistics and data science at Yale, to develop software that disentangles subtle noise sources in the stellar spectrum.Fischer said the result should be quite telling. "It's equivalent to the difference between early digital cameras from 10 years ago and the latest smartphone photography," she said.With EXPRES up and running in Arizona, and the similarly advanced ESPRESSO spectrometer built by Swiss astronomers in Chile, Fischer and other exoplanet researchers are preparing for a wealth of new data that might dramatically advance the search for extrasolar life."We've designed some very clever tests," she explained. "It's going to be amazing."
  • NASA's Kepler Spacecraft Nearing the End as Fuel Runs Low
    21.03.2018 02:09:10
    NASA's Kepler Spacecraft Nearing the End as Fuel Runs Low Washington DC (SPX) Mar 15, 2018 -
    Trailing Earth's orbit at 94 million miles away, the Kepler space telescope has survived many potential knock-outs during its nine years in flight, from mechanical failures to being blasted by cosmic rays. At this rate, the hardy spacecraft may reach its finish line in a manner we will consider a wonderful success. With nary a gas station to be found in deep space, the spacecraft is going to run out of fuel. We expect to reach that moment within several months.In 2013, Kepler's primary mission ended when a second reaction wheel broke, rendering it unable to hold its gaze steady at the original field of view. The spacecraft was given a new lease on life by using the pressure of sunlight to maintain its pointing, like a kayak steering into the current.Reborn as "K2," this extended mission requires the spacecraft to shift its field of view to new portions of the sky roughly every three months in what we refer to as a "campaign." Initially, the Kepler team estimated that the K2 mission could conduct 10 campaigns with the remaining fuel. It turns out we were overly conservative. The mission has already completed 16 campaigns, and this month entered its 17th.Our current estimates are that Kepler's tank will run dry within several months - but we've been surprised by its performance before! So, while we anticipate flight operations ending soon, we are prepared to continue as long as the fuel allows.The Kepler team is planning to collect as much science data as possible in its remaining time and beam it back to Earth before the loss of the fuel-powered thrusters means that we can't aim the spacecraft for data transfer. We even have plans to take some final calibration data with the last bit of fuel, if the opportunity presents itself.Without a gas gauge, we have been monitoring the spacecraft for warning signs of low fuel- such as a drop in the fuel tank's pressure and changes in the performance of the thrusters. But in the end, we only have an estimate - not precise knowledge. Taking these measurements helps us decide how long we can comfortably keep collecting scientific data.It's like trying to decide when to gas up your car. Do you stop now? Or try to make it to the next station? In our case, there is no next station, so we want to stop collecting data while we're still comfortable that we can aim the spacecraft to bring it back to Earth. We will continue to provide updates on the science and the spacecraft, which has yet to show warning signs.Many NASA missions must set a course for a clear-cut ending and reserve enough fuel for one last maneuver. For example, Earth-orbiting spacecraft must avoid collisions with other satellites or an uncontrolled fall to the ground, while planetary missions like Cassini have to reserve fuel to avoid contamination of a potentially life-bearing environment.In Cassini's case, NASA sent the spacecraft into Saturn rather than risk it falling into one of the planet's moons. Deep space missions like Kepler are nowhere near Earth or sensitive environments, which means we can afford to squeeze every last drop of data from the spacecraft - and ultimately that means bringing home even more data for science. Who knows what surprises about our universe will be in that final downlink to Earth?While Kepler continues to bring us exciting data as it draws close the finish line, the Transiting Exoplanet Survey Satellite (TESS) will be launching on April 16 from Cape Canaveral, Florida. TESS will search nearly the entire sky for planets outside our solar system, focusing on the brightest stars less than 300 light-years away, and adding to Kepler's treasure trove of planet discoveries.
  • Heat shock system helps bug come back to life after drying up
    21.03.2018 02:09:10
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    Heat shock system helps bug come back to life after drying up Tokyo, Japan (SPX) Mar 12, 2018 -
    The larva of the sleeping chironomid, Polypedilum vanderplanki - a mosquito-like insect that inhabits semi-arid areas of Africa - is well known for being able to come back to life after being nearly completely desiccated, losing up to 97 percent of its body's water content. However, the genetic mechanisms the insects use to achieve this feat, and, especially is the identity of the master gene that induces desiccation tolerance have remained largely elusive.Now, researchers from an international collaboration including Oleg Gusev of the RIKEN Innovation Center and collaborators from NARO, Kazan Federal University (Russia) and Skoltech University (Russia) have discovered that a gene called heat shock factor - which is present in some form in nearly all living organisms on earth - has been coopted by the species to survive desiccation.Heat shock factor - which exists in a single form in invertebrates but multiple forms in vertebrates - is an essential part of the ability of living cells to survive stressful conditions such as heat, cold, radiation, and, it turns out, desiccation. In desert insects, the researchers found, the gene is able in certain conditions to upregulate itself, and this upregulation leads to a number of downstream processes, including the synthesis of heat shock proteins that are able to protect proteins in the cell from misfolding.To perform the research, published in the Proceedings of the National Academy of Sciences, the researchers compared data on RNA expression in the sleeping chironomid with a closely related species, Polypedilum nubifer, which is not capable of surviving desiccation. They found that in the sleeping chironomid, hundreds of genes, including genes known to be involved in forming a "molecular shield" against damage due to dehydration, were already expressed during the early stages of desiccation.They discovered that a certain DNA motif, TCTAGAA, which is the binding site for HSF, was strongly enriched around the transcription start site of the genes activated by desiccation in the sleeping chironomid, but not the other species. Intriguingly, they found that in the desiccation-tolerant species, but not the other, genes responsible for the synthesis of trehalose - a sugar that can stabilize cells in a dry state - contained the TCTAGAA motif.To shed further light on the role of trehalose, they treated a cultured cell line from the sleeping chironomid with the sugar, and found that many of the genes activated by desiccation were also activated, and further, that the trehalose treatment led to the activation of the HSF gene. This effect of trehalose was prevented by knocking down the HSF gene, showing the HSF was clearly involved in the response.According to Oleg Gusev, who led the group, "The discovery that heat shock factor is an important regulator of gene expression in response to desiccation was very interesting for us. It seems that these extremophilic insects in the process of evolution have coopted a very conservative transcription factor and its action for their own needs to survive without water by evolving a special gene structure and "adjusting" their genome sequence for these "needs".Our data suggests the following story: HSF is activated during dehydration, and then HSF actually self-activates by binding to the upstream region of its own gene. This leads to the activation of the downstream genes that allow the insects to survive desiccation. What was very surprising to us was the finding that trehalose itself can activate HSF."Looking to the future, he continues, "One potential application of this finding will be in preserving cells outside the body in a dry state, if we can active the HSF gene. We now have a good understanding of how it works in this insect, so we will want to investigate if this is true for other organisms as well."Research paper
  • Can Space Junk Help Us Find Aliens?
    21.03.2018 02:09:10
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    Can Space Junk Help Us Find Aliens? Moscow (Sputnik) Mar 12, 2018 -
    Astrophysicists came up with an unusual idea to detect sentient life-forms in the distant parts of the universe, with the possibility to become a major breakthrough.Humanity has left significant amounts of junk floating in Earth's orbit since it began to explore space. However, astrophysicists from the Canary Islands Institute of Astrophysics have found something positive about it - it is an indication that a lifeform intelligent enough to at least launch satellites inhabits the planet.This means that if we can see similar "space trash" orbiting some distant planet, it may be a pretty powerful clue that the planet is also inhabited with intelligent lifeforms, or at least has been at some point.Skeptics, however, point out a significant flaw in the theory - from distances that far away, natural planetary satellites, like small moons or asteroid rings, may very well resemble space junk left by an advanced civilization during its conquest of space.Professor Hector Socas-Navarro from the Canary Islands Institute of Astrophysics discarded the criticism by noting that an artificial satellite can be mistaken for natural one, and that while looking for the latter you may by chance find the former.Source: Sputnik News
  • Study sheds light on the genetic origins of the two sexes
    21.03.2018 02:09:10
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    Study sheds light on the genetic origins of the two sexes St Louis, MO (SPX) Mar 14, 2018 -
    A new study published in the journal Communications Biology has shed light on the earliest stages in the evolution of male-female differentiation and sex chromosomes--and found the genetic origins of the two sexes to be unexpectedly modest.James Umen, Ph.D., member, Enterprise Rent-a-Car Institute for Renewable Fuels and Joseph Varner Distinguished Investigator at the Donald Danforth Plant Science Center was part of a research team led by Dr. Hisayoshi Nozaki at the University of Tokyo who have been investigating the evolution of male and female sexes in a group of freshwater photosynthetic protists called volvocine green algae, a group that is well-known to scientists for capturing early stages in the evolution of sexes and multicellularity.Previous studies in animals and plants identified a general trend of expansion and differentiation between male and female sex chromosomes, often leading to large genetic differences between them; but these studies could not capture the earliest stages of evolution where distinct sperm and egg cell types first evolved from a simpler ancestral mating system with equal-sized gametes, known as isogamy.The research team focused on two especially informative and closely-related multicellular volvocine species from the genera Yamagishiella and Eudorina which bracket the transition from isogamy to male/female sexes. While 32-celled Yamagishiella and Eudorina colonies look very similar to each other, the former is isogamous while the latter produces small male gametes and large female gametes. The team used high-throughput genome sequencing of the chromosomal regions that specify mating type in Yamagishiella and male-female differentiation in Eudorina, and then compared these regions.While evolutionary theory predicted an expansion and/or increased genetic complexity of the sex determining region associated with the evolution of sexes in Eudorina, the results of the study showed the opposite, with Eudorina having the most diminutive and genetically least complex sex-determining region found to date found among all volvocine species. In essence, the major difference between males and females in Eudorina could be reduced to the presence or absence of a single gene called MID that resides in a tiny chromosomal region."This new study punches a hole in the idea that increased genetic complexity of sex chromosomes accompanied the origin of sexes," said Umen. "Moreover, the work also has practical implications since it expands our understanding of how to identify mating types and sexes in new species of algae that we might want to breed as crops for improved traits relating to biofuel or biotechnology applications."Research paper
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