Bacteria can multiply disease-inducing genes to rapidly cause infection

Illustration of the discovery by Umeå researchers. To the left: inactive Yersinia bacteria with just one ring-shaped DNA strand cannot cause infection. To the right: active Yersinia bacteria with multiple DNA plasmids which can cause intestinal disease in the mouse.

Researchers at Umeå University in Sweden are first to discover that bacteria can multiply disease-inducing genes which are needed to rapidly cause infection. The results were published in Science on June 30, 2016.

More than 22 years ago, researchers at Umeå University were first to discover an infection strategy of human pathogenic Yersinia bacteria -- a protein structure in bacterial cell-walls that resembled a syringe. The structure, named "Type III secretion system" or T3SS, makes it possible to transfer bacterial proteins into the host cell and destroy its metabolism.

After the discovery, researchers have found T3SS in several other bacteria species and T3SS has proven to be a common infection mechanism that pathogens, i.e. an infectious agent such as a virus or bacterium, use to destroy host cells. Now, Umeå researchers are again first to find a link between infection and rapid production of the essential proteins needed to form "the poisonous syringe."

Together with researchers at the Helmholtz Centre for Infection Research in Braunschweig, Germany, the Umeå researchers investigated the virulence strategy of Yersinia pseudotuberculosis. This bacterium can cause acute diarrhea, vomiting and stomach pains, and is closely related to the deadly plague bacterium, which it shares many infection mechanisms with. The genes that these bacteria need for infection are located on a circular extra chromosome, called the virulence plasmid.

Researchers at Umeå Centre for Microbial Research (UCMR), The Laboratory for Molecular Infection Medicine Sweden (MIMS) at the Department of Molecular Biology first performed infection experiments in cell cultures with human cells and then confirmed their findings using animal models. It turned out that a single copy of the virulence plasmid was not sufficient to induce infection, but the researchers discovered that when Yersinia came in contact with host cells, it triggered a "copying machine" that increased the number of plasmids.

"Yersinia has developed a very clever strategy," says postdoctoral fellow Helen Wang who carried out a large portion of the experiments. "To carry a great number of plasmids, the bacteria need a lot of energy and it negatively affects the bacteria's metabolism and growth. But having one copy of the plasmid as a blueprint that can be rapidly amplified in case of infection is a very clever solution. Many copies of the plasmids give bacteria the opportunity to build up many T3SS and all the proteins needed to quickly knock out host cells during an infection," continues Helen Wang.

It is the first time researchers can demonstrate that an increased number of plasmid-encoded genes is necessary for successful infection by pathogenic bacteria.

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In the blink of a cosmic eye: Chance microlensing events probe galactic cores

Artist's rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun.

Some galaxies pump out vast amounts of energy from a very small volume of space, typically not much bigger than our own solar system. The cores of these galaxies, so called Active Galactic Nuclei or AGNs, are often hundreds of millions or even billions of light years away, so are difficult to study in any detail. Natural gravitational 'microlenses' can provide a way to probe these objects, and now a team of astronomers have seen hints of the extreme AGN brightness changes that hint at their presence. Leading the microlensing work, PhD student Alastair Bruce of the University of Edinburgh presents their work today (Friday 1 July) at the National Astronomy Meeting in Nottingham.

The energy output of an AGN is often equivalent to that of a whole galaxy of stars. This is an output so intense that most astronomers believe only gas falling in towards a supermassive black hole -- an object with many millions of times the mass of the Sun -- can generate it. As the gas spirals towards the black hole it speeds up and forms a disc, which heats up and releases energy before the gas meets its demise.

Scientists are particularly interested in seeing what happens to the gas as it approaches the black hole. But studying such small objects at such large distances is tricky, as they simply look like points of light in even the best telescopes. Observations with spectroscopy (where light from an object is dispersed into its component colours) show that fast moving clouds of emitting material surround the disc but the true size of the disc and exact location of the clouds are very difficult to pin down.

Bruce will describe how astronomers can make use of cosmic coincidences, and benefit from a phenomenon described by Einstein's general theory of relativity more than a century ago. In his seminal theory, Einstein described how light travels in curved paths under the influence of a gravitational field. So massive objects like black holes, but also planets and stars, can act to bend light from a more distant object, effectively becoming a lens.

This means that if a planet or star in an intervening galaxy passes directly between the Earth and a more distant AGN, over a few years or so they act as a lens, focusing and intensifying the signal coming from near the black hole. This type of lensing, due to a single star, is termed microlensing. As the lensing object travels across the AGN, emitting regions are amplified to an extent that depends on their size, providing astronomers with valuable clues.

Bruce and his team believe they have already seen evidence for two microlensing events associated with AGN. These are well described by a simple model, displaying a single peak and a tenfold increase in brightness over several years. MIcrolensing in AGNs has been seen before, but only where the presence of the galaxy was already known. Now Bruce and his team are seeing the extreme changes in brightness that signifies the discovery of both previously unknown microlenses and AGNs.

Bruce says: "Every so often, nature lends astronomers a helping hand and we see a very rare event. It's remarkable that an unpredictable alignment of objects billions of light years away could help us probe the surroundings of black holes. In theory, microlensing could even let us see detail in accretion discs and the clouds in their vicinity. We really need to take advantage of these opportunities whenever they arise."

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Jupiter on a bench: Spacecraft Juno nears planet orbit

Harvard researchers observed evidence of the transition of hydrogen to metallic hydrogen by squeezing a sample of liquid hydrogen between two diamond tips.

In less than a week, the spacecraft Juno will arrive at Jupiter, the culmination of a five-year, billion-dollar journey. It's mission: to peer deep inside the gas giant and unravel its origin and evolution. One of the biggest mysteries surrounding Jupiter is how it generates its powerful magnetic field, the strongest in the solar system.

One theory is that about halfway to Jupiter's core, the pressures and temperatures become so intense that the hydrogen that makes up 90 percent of the planet -- molecular gas on Earth -- looses hold of its electrons and begins behaving like a liquid metal. Oceans of liquid metallic hydrogen surrounding Jupiter's core would explain its powerful magnetic field.

But how and when does this transition from gas to liquid metal occur? How does it behave? Researchers hope that Juno will shed some light on this exotic state of hydrogen -- but one doesn't need to travel all the way to Jupiter to study it.

Four hundred million miles away, in a small, windowless room in the basement of Lyman Laboratory on Oxford Street in Cambridge, Massachusetts, there was, for a fraction of a fraction of a second, a small piece of Jupiter.

Earlier this year, in an experiment about five-feet long, Harvard University researchers say they observed evidence of the abrupt transition of hydrogen from liquid insulator to liquid metal. It is one of the first times such a transition has ever been observed in any experiment.

They published their research in Physical Review B.

"This is planetary science on the bench," said Mohamed Zaghoo, the NASA Earth & Space Science Fellow at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS). "The question of how hydrogen transitions into a metallic state -- whether that is an abrupt transition or not -- has huge implications for planetary science. How hydrogen transitions inside Jupiter, for example, says a lot about the evolution, the temperature and the structure of these gas giants interiors."

In the experiment, Zaghoo, Ashkan Salamat, and senior author Isaac Silvera, the Thomas D. Cabot Professor of the Natural Sciences, recreated the extreme pressures and temperatures of Jupiter by squeezing a sample of hydrogen between two diamond tips, about 100 microns wide, and firing short bursts of lasers of increasing intensity to raise the temperature.

This experimental setup is significantly smaller and cheaper than other current techniques to generate metallic hydrogen, most of which rely on huge guns or lasers that generate shock waves to heat and pressurize hydrogen.

The transition of the liquid to metallic hydrogen happens too quickly for human eyes to observe and the sample lasts only a fraction of a second before it deteriorates. So, instead of watching the sample itself for evidence of the transition, the team watched lasers pointed at the sample. When the phase transition occurred, the lasers abruptly reflected.

"At some point, the hydrogen abruptly transitioned from an insulating, transparent state, like glass, to a shiny metallic state that reflected light, like copper, gold or any other metal," Zaghoo said. "Because this experiment, unlike shock wave experiments, isn't destructive, we could run the experiment continuously, doing measurements and monitoring for weeks and months to learn about the transition."

"This is the simplest and most fundamental atomic system, yet modern theory has large variances in predictions for the transition pressure," Silvera said. "Our observation serves as a crucial guide to modern theory."

The results represent a culmination of decades of research by the Silvera group. The data collected could begin to answer some of the fundamental questions about the origins of solar systems.

Metallic hydrogen also has important ramifications here on Earth, especially in energy and materials science.

"A lot of people are talking about the hydrogen economy because hydrogen is combustibly clean and it's very abundant," said Zaghoo. "If you can compress hydrogen into high density, it has a lot of energy compacted into it."

"As a rocket fuel, metallic hydrogen would revolutionize rocketry as propellant an order of magnitude more powerful than any known chemical," said Silvera. "This could cut down the time it takes to get to Mars from nine months to about two months, transforming prospects of human space endeavors."

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Gelatin instead of the gym to grow stronger muscles

Skeletal myotubes grown for three weeks on gelatin hydrogel.

USC researcher Megan L. McCain and colleagues have devised a way to develop bigger, stronger muscle fibers. But instead of popping up on the bicep of a bodybuilder, these muscles grow on a tiny scaffold or "chip" molded from a type of water-logged gel made from gelatin.

First authors Archana Bettadapur and Gio C. Suh describe these muscles-on-a-chip in a new study published in Scientific Reports.

During normal embryonic development, skeletal muscles form when cells called myoblasts fuse to form muscle fibers, known as myotubes.

In past experiments, mouse myotubes have detached or delaminated from protein-coated plastic scaffolds after approximately one week and failed to thrive.

In this experiment, the researchers fabricated a gel scaffold from gelatin, a derivative of the naturally occurring muscle protein collagen, and achieved much better results. After three weeks, many of the mouse myotubes were still adhering to these gelatin chips, and they were longer, wider and more developed as a result.

The researchers anticipate that human myotubes would thrive equally well on gelatin chips. These new and improved "muscles-on-a-chip" could then be used to study human muscle development and disease, as well as provide a relevant testing ground for new potential drugs.

"Disease and disorders involving skeletal muscle -- ranging from severe muscular dystrophies to the gradual decrease in muscle mass with aging -- dramatically reduce the quality of life for millions of people," said McCain, assistant professor of biomedical engineering at the USC Viterbi School of Engineering, and stem cell biology and regenerative medicine at the Keck School of Medicine of USC. "By creating an inexpensive and accessible platform for studying skeletal muscle in the laboratory, we hope to enable research that will usher in new treatments for these patients."

McCain is already putting the gelatin chips into action as the winner of an Eli and Edythe Broad Innovation Awards in Stem Cell Biology and Regenerative Medicine at USC. The award provides $120,000 to McCain and her two collaborators: Justin Ichida, assistant professor of stem cell biology and regenerative medicine; and Dion Dickman, assistant professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences. In their project, they will use the gelatin chips for studying amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, which damages the intersections between motor nerve cells and muscle cells, called neuromuscular junctions (NMJs). McCain, Ichida and Dickman will use skin or blood cells from patients with ALS to generate and study NMJs on gelatin chips.

From Science Daily

Spiderweb galaxy: Watery dew drops surrounding dusty spider’s web

Astronomers have spotted glowing droplets of condensed water in the distant Spiderweb Galaxy -- but not where they expected to find them. Detections with the Atacama Large Millimeter/submillimeter Array (ALMA) show that the water is located far out in the galaxy and therefore cannot be associated with central, dusty, star-forming regions, as previously thought.

"Observations of light emitted by water and by dust often go hand-in-hand. We usually interpret them as an insight into star-forming regions, with the illumination from young stars warming dust particles and water molecules until they start to glow. Now, thanks to the power of ALMA, we can -- for the first time -- separate out the emissions from the dust and water populations, and pinpoint their exact origins in the galaxy. The results are quite unexpected in that we've found that the water is located nowhere near the dusty stellar nurseries," explained Dr Gullberg, of the Centre for Extragalactic Astronomy, Durham University, UK.

The Spiderweb Galaxy is one of the most massive galaxies known. It lies 10 billion light-years away and is made up of dozens of star-forming galaxies in the process of merging together. The ALMA observations show that the light from the dust originates in the Spiderweb Galaxy itself. However, the light from the water is concentrated in two regions far to the east and west of the galaxy core.

Gullberg and her colleagues believe that the explanation lies with powerful jets of radio waves that are ejected from a supermassive black hole at the centre of the Spiderweb Galaxy. The radio jets compress clouds of gas along their path and heat up water molecules contained within the clouds until they emit radiation.

"Our results show how important it is to pinpoint the exact locations and origins for light in galaxies. We may also have new clues to the processes that trigger star formation in interstellar clouds," said Gullberg. "Stars are born out of cold, dense molecular gas. The regions in the Spiderweb where we've detected water are currently too hot for stars to form. But the interaction with the radio jets changes the composition of the gas clouds. When the molecules have cooled down again, it will be possible for the seeds of new stars to form. These "dew drop" regions could become the next stellar nurseries in this massive, complex galaxy."

The results will be presented at the National Astronomy Meeting 2016 in Nottingham by Dr Bitten Gullberg on Friday 1st July.

From Science Daily

Shape-changing 'smart' material: Heat, light stimulate self-assembly

A smart new material reacts to light, can remember its shape as it folds and unfolds and can heal itself when damaged.

Washington State University researchers have developed a unique, multifunctional smart material that can change shape from heat or light and assemble and disassemble itself. They have filed a provisional patent on the work.

This is the first time researchers have been able to combine several smart abilities, including shape memory behavior, light-activated movement and self-healing behavior, into one material. They have published their work in ACS Applied Materials & Interfaces.

The work is led by Michael Kessler, professor and Berry Family director and in the WSU School of Mechanical and Materials Engineering (MME), and Yuzhan Li, MME staff scientist, in collaboration with Orlando Rios, a researcher at Oak Ridge National Laboratory.

Adding functional versatility

Smart materials that can react to external stimuli, like light or heat, have been an interesting novelty and look almost magical as they mysteriously fold and unfold themselves. They have a variety of potential applications, such as for actuators, drug delivery systems and self-assembling devices. For instance, smart materials could change shape to unfold a solar panel on a space satellite without need of a battery-powered mechanical device.

But smart materials haven't come into widespread use because they are difficult to make and often can only perform one function at a time. Researchers also have struggled to reprocess the material so its special properties can continually repeat themselves.

The WSU research team developed a material that allows multiple functions at once with potential to add more.

Fold and unfold, remember and heal

The team worked with a class of long-chain molecules, called liquid crystalline networks (LCNs), which provide order in one direction and give material unique properties. The researchers took advantage of the way the material changes in response to heat to induce a unique three-way shape shifting behavior. They added groups of atoms that react to polarized light and used dynamic chemical bonds to improve the material's reprocessing abilities.

"We knew these different technologies worked independently and tried to combine them in a way that would be compatible,'' said Kessler.

The resulting material reacts to light, can remember its shape as it folds and unfolds and can heal itself when damaged. For instance, a razor blade scratch in the material can be fixed by applying ultraviolet light. The material's movements can be preprogrammed and its properties tailored.

The Oak Ridge National Laboratory researchers used facilities at their Center for Nanophase Materials Sciences to study the mechanisms responsible for the material's unique abilities.

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A 6,000 year old telescope without a lens: Prehistoric tombs enhanced astronomical viewing

a) Dolmen da Orca, a typical dolmenic structure in western Iberia; b) view of the passage and entrance while standing within the dolmens' chamber: the 'window of visibility'; c) Orca de Santo Tisco, a dolmen with a much smaller passage or corridor.

Astronomers are exploring what might be described as the first astronomical observing tool, potentially used by prehistoric humans 6,000 years ago. They suggest that the long, narrow entrance passages to ancient stone, or 'megalithic', tombs may have enhanced what early human cultures could see in the night sky, an effect that could have been interpreted as the ancestors granting special power to the initiated. The team present their study at the National Astronomy Meeting, being held this week in Nottingham.

The team's idea is to investigate how a simple aperture, for example an opening or doorway, affects the observation of slightly fainter stars. They focus this study on passage graves, which are a type of megalithic tomb composed of a chamber of large interlocking stones and a long narrow entrance. These spaces are thought to have been sacred, and the sites may have been used for rites of passage, where the initiate would spend the night inside the tomb, with no natural light apart from that shining down the narrow entrance lined with the remains of the tribe's ancestors.

These structures could therefore have been the first astronomical tools to support the watching of the skies, millennia before telescopes were invented. Kieran Simcox, a student at Nottingham Trent University, and leading the project, comments: "It is quite a surprise that no one has thoroughly investigated how for example the colour of the night sky impacts on what can be seen with the naked eye."

The project targets how the human eye, without the aid of any telescopic device, can see stars given sky brightness and colour. The team intend to apply these ideas to the case of passage graves, such as the 6,000 year old Seven-Stone Antas in central Portugal. Dr Fabio Silva, of the University of Wales Trinity Saint David, explains that, "the orientations of the tombs may be in alignment with Aldebaran, the brightest star in the constellation of Taurus. To accurately time the first appearance of this star in the season, it is vital to be able to detect stars during twilight."

The first sighting in the year of a star after its long absence from the night sky might have been used as a seasonal marker, and could indicate for example the start of a migration to summer grazing grounds. The timing of this could have been seen as secret knowledge or foresight, only obtained after a night spent in contact with the ancestors in the depths of a passage grave, since the star may not have been observable from outside. However, the team suggest it could actually have been the result of the ability of the human eye to spot stars in such twilight conditions, given the small entrance passages of the tombs.

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It's not easy being green: What colors tell us about galaxy evolution

The green galaxy is caught in the act of transforming from blue to red as its gas supply runs out.

An international team of scientists, led from Durham's Institute for Computational Cosmology (ICC), used new computer modelling of the Universe to investigate the colours that galaxies have and what those colours might tell us about how galaxies evolve.

Using the state-of-the-art EAGLE simulations, the researchers modelled how both the ages of stars in galaxies and what those stars are made from translate into the colour of light that they produce.

The research team said its simulations showed that colours of galaxies can also help diagnose how they evolve.

While red and blue galaxies are relatively common, rare green galaxies are likely to be at an important stage in their evolution, when they are rapidly turning from blue -- when new stars and planets are being born -- to red as stars begin to burn themselves out.

The research funded by the Science and Technology Facilities Council (STFC) and the European Research Council (ERC) is being presented today (Thursday 30 June) at the Royal Astronomical Society's National Astronomy Meeting in Nottingham, UK.

Lead researcher James Trayford, PhD student in the ICC at Durham University, said: "Galaxies emit a healthy blue glow while new stars and planets are being born. However, if the formation of stars is halted galaxies turn red as stars begin to age and die.

"In the real Universe we see many blue and red galaxies, but these intermediate 'green' galaxies are more rare.

"This suggests that the few green galaxies we catch are likely to be at a critical stage in their evolution; rapidly turning from blue to red."

Because stars form from dense gas, a powerful process is needed to rapidly destroy their gas supply and cause such dramatic changes in colour, the research found.

James added: "In a recent study we followed simulated galaxies as they changed colour, and investigated what processes caused them to change.

"We typically find that smaller green galaxies are being violently tossed around by the gravitational pull of a massive neighbour, causing their gas supply to be stripped away.

"Meanwhile, bigger green galaxies may self-destruct as immense explosions triggered by super-massive black holes at their centres can blow dense gas away."

However, the research found that there was some hope for green galaxies as a lucky few might absorb a fresh supply of gas from their surroundings.

This can revive the formation of stars and planets, and restore galaxies to a healthy blue state.

James said: "By using simulations to study how galaxy colours change, we can speed up the process of galaxy evolution from the billions of years it takes in the real Universe to just a matter of days in a computer.

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Hubble captures vivid auroras in Jupiter’s atmosphere

This image combines an image taken with Hubble Space Telescope in the optical (taken in spring 2014) and observat ions of its auroras in the ultraviolet, taken in 2016.

Astronomers are using the NASA/ESA Hubble Space Telescope to study auroras -- stunning light shows in a planet's atmosphere -- on the poles of the largest planet in the Solar System, Jupiter. This observation programme is supported by measurements made by NASA's Juno spacecraft, currently on its way to Jupiter.

Jupiter, the largest planet in the Solar System, is best known for its colourful storms, the most famous being the Great Red Spot. Now astronomers have focused on another beautiful feature of the planet, using the ultraviolet capabilities of the NASA/ESA Hubble Space Telescope.

The extraordinary vivid glows shown in the new observations are known as auroras. They are created when high energy particles enter a planet's atmosphere near its magnetic poles and collide with atoms of gas. As well as producing beautiful images, this programme aims to determine how various components of Jupiter's auroras respond to different conditions in the solar wind, a stream of charged particles ejected from the Sun.

This observation programme is perfectly timed as NASA's Juno spacecraft is currently in the solar wind near Jupiter and will enter the orbit of the planet in early July 2016. While Hubble is observing and measuring the auroras on Jupiter, Juno is measuring the properties of the solar wind itself; a perfect collaboration between a telescope and a space probe.

"These auroras are very dramatic and among the most active I have ever seen," says Jonathan Nichols from the University of Leicester, UK, and principal investigator of the study. "It almost seems as if Jupiter is throwing a firework party for the imminent arrival of Juno."

To highlight changes in the auroras Hubble is observing Jupiter daily for around one month. Using this series of images it is possible for scientists to create videos that demonstrate the movement of the vivid auroras, which cover areas bigger than the Earth.

Not only are the auroras huge, they are also hundreds of times more energetic than auroras on Earth. And, unlike those on Earth, they never cease. Whilst on Earth the most intense auroras are caused by solar storms -- when charged particles rain down on the upper atmosphere, excite gases, and cause them to glow red, green and purple -- Jupiter has an additional source for its auroras.

The strong magnetic field of the gas giant grabs charged particles from its surroundings. This includes not only the charged particles within the solar wind but also the particles thrown into space by its orbiting moon Io, known for its numerous and large volcanos.

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It's not just a grunt: Pigs really do have something to say

The study indicated that pigs with more proactive personality types produced grunts at a higher rate than the more reactive animals.

The grunts made by pigs vary depending on the pig's personality and can convey important information about the welfare of this highly social species, new research has found.

Scientists specialising in animal behaviour and welfare devised an experiment to investigate the relationship between personality and the rate of grunting in pigs. They also examined the effect different quality living conditions had on these vocalisations.

Findings from the study, carried out by researchers from the University of Lincoln, UK, and Queens University Belfast, are published in the Royal Society journal Open Science.

The study involved 72 male and female juvenile pigs. Half were housed in spacious 'enriched' pens with straw bedding, while the other half were kept in more compact 'barren' pens with partially slatted concrete floors, which adhered to UK welfare requirements.

To get a measure of the pigs' personalities, the researchers conducted two tests: a social isolation test and a novel object test. Each pig spent three minutes in social isolation, and five minutes in a pen with a large white bucket or an orange traffic cone they had not previously encountered. Their behaviour, including vocalisations, were observed. These tests were repeated two weeks later, allowing the researchers to determine if the pigs' responses were repeatable -- the defining characteristic of personality (also known as 'coping style' in animals).

They also recorded the frequency of grunts they made by counting the number of grunts produced per minute of the test, and investigated the effect different quality environments had on the sounds made.

The study indicated that pigs with more proactive personality types produced grunts at a higher rate than the more reactive animals. The study also found that male pigs (but not females) kept in the lower-quality conditions made fewer grunts compared with those housed in the enriched environment, suggesting greater susceptibility among male pigs to environmental factors.

The results add to evidence that acoustic signalling indicates personality in pigs. This may have had far reaching consequences in shaping the evolution of social behaviours, the researchers believe. The findings also suggest personality needs to be kept in mind when using vocalisation as a measure of the animals' welfare status.

Principal investigator, Dr Lisa Collins, a specialist in animal health, behaviour and welfare epidemiology in the School of Life Sciences at the University of Lincoln, said: "The domestic pig is a highly social and vocal species which uses acoustic signals in a variety of ways; maintaining contact with other group members while foraging, parent-offspring communication, or to signal if they are distressed.

"The sounds they make convey a wide range of information such as the emotional, motivational and physiological state of the animal. For example, squeals are produced when pigs feel fear, and may be either alerting others to their situation or offering assurance. Grunts occur in all contexts, but are typical of foraging to let other members of the group know where they are."

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