Japanese scientists are shedding new light on the importance of light-sensing cells in the retina that process visual information. The researchers isolated the functions of melanopsin cells and demonstrated their crucial role in the perception of visual environment. This ushers in a new understanding of the biology of the eye and how visual information is processed.
The findings could contribute to more effective therapies for complications that relate to the eye. They can also serve as the basis for developing lighting and display systems.
The research was published in Scientific Reports on May 20th, 2019.
The back of the human eye is lined with the retina, a layer of various types of cells, called photoreceptors, that respond to different amounts of light. The cells that process a lot of light are called cones and those that process lower levels of light are named rods.
Up until recently, researchers have thought that when light struck the retina, rods and cones were the only two kinds of cells that react. Recent discoveries have revealed an entirely new type of cells, called intrinsically photosensitive retinal ganglion cells (ipRGCs). Unlike rods and cones, ipRGCs contain melanopsin, a photopigment that is sensitive to light. While it has been established that ipRGCs are involved in keeping the brain's internal clock in sync with changes in daylight, their importance in the detection of the amount of light had not yet been well understood.
"Until now, the role of retinal melanopsin cells and how they contribute to the perception of the brightness of light have been unclear," said Katsunori Okajima, a professor at the Faculty of Environment and Information Sciences, Yokohama National University and one of the authors of the study.
"We've found that melanopsin plays a crucial role on the human ability to see how well-lit the environment is. These findings are redefining the conventional system of light detection that so far has only taken into consideration two variables, namely brightness and the amount of incoming light. Our results suggest that brightness perception should rely on a third variable -- the intensity of a stimulus that targets melanopsin."
In the study, the authors showed how cones and melanopsin combine to allow the perception of brightness. In order to better assess the contribution of melanopsin to the detection of light, the melanopsin's signals were isolated from cones and rods. This separation allowed for more accurate observation of the melanopsin signal alone. Visual stimuli were carefully designed and positioned in order to specifically stimulate the light-sensitive chemical. Also, the researchers used tracking software to measure study participants' pupil diameters under each visual stimulus. This served as a way to determine the relationship between brightness perception and the actual visual stimulus intensity on the retina.
Read more at Science Daily
Aug 18, 2019
Schrödinger's cat with 20 qubits
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| Cat in box. |
Since the early 1980s, researchers have been able to realize this superposition of quantum states experimentally in the laboratory using various approaches. "However, these cat states are extremely sensitive. Even the smallest thermal interactions with the environment cause them to collapse," explains Tommaso Calarco from Forschungszentrum Jülich. Among other things, he plays a leading role in Europe's major quantum initiative, the EU's Quantum Flagship programme. "For this reason, it is only possible to realize significantly fewer quantum bits in Schrödinger cat states than those that exist independently of each other."
Of the latter states, scientists can now control more than 50 in laboratory experiments. However, these quantum bits, or qubits for short, do not display the special characteristics of Schrödinger's cat in contrast to the 20 qubits that the team of researchers have now created using a programmable quantum simulator thus establishing a new record that is still valid even if other physical approaches with optical photons, trapped ions or superconducting quantum circuits are taken into account.
Experts from several of the world's most renowned institutions joined forces to develop the experiment. In addition to the Jülich researchers, scientists from numerous top American universities -- Harvard, Berkeley, MIT and Caltech -- as well as the Italian University of Padua were involved.
"Qubits in the cat state are considered extremely important for the development of quantum technologies," explains Jian Cui. "The secret of the enormous efficiency and performance expected of future quantum computers is to be found in this superposition of states," says the physicist from the Peter Grünberg Institute at Jülich (PGI-8).
Classical bits in a conventional computer always only have one certain value, which is composed of 0 and 1, for example. Therefore, these values can only be processed bit by bit one after the other. Qubits, which have several states simultaneously due to the superposition principle, can store and process several values in parallel in one step. The number of qubits is crucial here. You don't get far with just a handful of qubits. But with 20 qubits, the number of superimposed states already exceeds one million. And 300 qubits can store more numbers simultaneously than there are particles in the universe.
The new result of 20 qubits now comes a little closer to this value, after the old record of 14 qubits remained unchanged since 2011. For their experiment, the researchers used a programmable quantum simulator based on Rydberg atom arrays. In this approach, individual atoms, in this case rubidium atoms, are captured by laser beams and held in place side by side in a row. The technique is also known as optical tweezers. An additional laser excites the atoms until they reach the Rydberg state, in which the electrons are located far beyond the nucleus.
This process is rather complicated and usually takes too much time, such that the delicate cat state is destroyed before it can even be measured. The group in Jülich contributed their expertise in Quantum Optimal Control to solve this issue. By cleverly switching the lasers off and on at the right rate, they achieved a speed up in the preparation process which made this new record possible.
"We practically inflated some atoms to such an extent that their atomic shells merge with the adjacent atoms to simultaneously form two opposite configurations, namely excitations occupying all even or odd sites," explains Jian Cui. "This goes so far that the wave functions overlap as in the analogy of Schrödinger's cat and we were able to create the superposition of the opposite configurations which is also known as the Greenberger-Horne-Zeilinger state."
Read more at Science Daily
Aug 17, 2019
Researcher decodes the brain to help patients with mental illnesses
Approximately 1 in 5 adults in the United States experience mental illness in a given year. Severe mental illnesses cause the brain to have trouble dealing with cognitively effortful states, like focusing attention over long periods of time, discriminating between two things that are difficult to tell apart, and responding quickly to information that is coming in fast.
A new study, published in the Journal of Neural Engineering, could improve patients' abilities to manage symptoms of mental illness.
Previous research demonstrated that applying electrical stimulation at just the right time helps the brain of a patient with a severe mental illness work through difficult cognitive tasks. However, it was done in a laboratory setting, free from the complexities of real-world activities of daily living.
Senior author Alik Widge, MD, Ph.D, Assistant Professor of Psychiatry at the University of Minnesota Medical School, and investigators at Massachusetts General Hospital (MGH), consisting of researchers from Brown University and MGH, including co-senior author David Borton, PhD, Assistant Professor of Engineering at Brown University, were the first to analyze patients' brain activity to detect precisely when a patient is focused and their attention is fully devoted, compared to when he or she is 'at rest'. They studied patients who were undergoing surgery for severe epilepsy, who already had measurement electrodes in the relevant brain areas.
The study, which was part of DARPA's SUBNETS program, found that specific signatures and algorithms can be used to tell when someone is focused and really trying to do a task that is hard for them, indicating that they could benefit from an electrical stimulation to get an extra push.
The study also demonstrates that there is no single region of the brain that can tell when someone is in this focused, effortful state. In order to detect when the patient started to focus on a cognitive task, the researchers had to analyze the information at the network level. It was essential to look at how the activity of one region coordinated with the activity of another.
"Using the same neural signals that could drive adaptive deep brain stimulation, we have shown that it is possible to detect mental states that might be amenable to closed-loop control," said lead author Nicole Provenza, MS, PhD candidate, Brown University. "While further research is necessary to generalize our findings to real-world applications, we hope that this work will ultimately contribute to the development of more effective brain stimulation therapies for mental illness."
"We want to take a patient-centered approach to treating mental illness," explained Widge. "The job of a stimulator is not to take away the symptoms; its job is to help the patient manage his or her symptoms. It gives the power back to the individual and just gives them a little extra help when they need it."
Read more at Science Daily
A new study, published in the Journal of Neural Engineering, could improve patients' abilities to manage symptoms of mental illness.
Previous research demonstrated that applying electrical stimulation at just the right time helps the brain of a patient with a severe mental illness work through difficult cognitive tasks. However, it was done in a laboratory setting, free from the complexities of real-world activities of daily living.
Senior author Alik Widge, MD, Ph.D, Assistant Professor of Psychiatry at the University of Minnesota Medical School, and investigators at Massachusetts General Hospital (MGH), consisting of researchers from Brown University and MGH, including co-senior author David Borton, PhD, Assistant Professor of Engineering at Brown University, were the first to analyze patients' brain activity to detect precisely when a patient is focused and their attention is fully devoted, compared to when he or she is 'at rest'. They studied patients who were undergoing surgery for severe epilepsy, who already had measurement electrodes in the relevant brain areas.
The study, which was part of DARPA's SUBNETS program, found that specific signatures and algorithms can be used to tell when someone is focused and really trying to do a task that is hard for them, indicating that they could benefit from an electrical stimulation to get an extra push.
The study also demonstrates that there is no single region of the brain that can tell when someone is in this focused, effortful state. In order to detect when the patient started to focus on a cognitive task, the researchers had to analyze the information at the network level. It was essential to look at how the activity of one region coordinated with the activity of another.
"Using the same neural signals that could drive adaptive deep brain stimulation, we have shown that it is possible to detect mental states that might be amenable to closed-loop control," said lead author Nicole Provenza, MS, PhD candidate, Brown University. "While further research is necessary to generalize our findings to real-world applications, we hope that this work will ultimately contribute to the development of more effective brain stimulation therapies for mental illness."
"We want to take a patient-centered approach to treating mental illness," explained Widge. "The job of a stimulator is not to take away the symptoms; its job is to help the patient manage his or her symptoms. It gives the power back to the individual and just gives them a little extra help when they need it."
Read more at Science Daily
How stress can curb the desire to eat in an animal model
Eating disorder researchers at The University of Texas Health Science Center at Houston (UTHealth) have discovered a neurocircuit in mice that, when activated, increased their stress levels while decreasing their desire to eat. Findings appear in Nature Communications.
The scientists believe their research could aid efforts to develop treatments for a serious eating disorder called anorexia nervosa, which has the highest mortality rate of any mental disorder, according to the National Institute of Mental Health. People with anorexia nervosa avoid food, severely restrict food, or eat very small quantities of only certain foods. Even when they are dangerously underweight, they may see themselves as overweight.
"We have identified a part of the brain in a mouse model that controls the impact of emotions on eating," said Qingchun Tong, PhD, the study's senior author and an associate professor in the Center for Metabolic and Degenerative Disease at McGovern Medical School at UTHealth.
Because mice and humans have similar nervous systems, Tong, the Cullen Chair in Molecular Medicine at UTHealth, believes their findings could shed light on the part of the human brain that regulates hunger.
The investigators believe they are among the first to demonstrate the role of this neurocircuit in the regulation of both stress and hunger.
While previous research has established that stress can both reduce and increase a person's desire to eat, the neural mechanisms that act on the regulation of eating by stress-related responses largely remain a mystery.
Tong's team focused on a neurocircuit connecting two parts of the mouse brain: the paraventricular hypothalamus, an eating-related zone in the brain, and the ventral lateral septum, an emotional zone in the brain. The neurocircuit acts as an on/off switch.
When researchers activated the neurocircuit, there was an increase in anxiety levels and a decrease in appetite. Conversely, when the investigators inhibited the neurocircuit, anxiety levels dropped and hunger increased.
The scientists used a research technique called optogenetics to turn the neurons in question on and off.
Yuanzhong Xu, PhD, the study's lead author and an instructor at McGovern Medical School, said additional preclinical tests are needed to confirm their findings.
Coauthors from UTHealth include Yungang Lu, PhD; Ryan Cassidy; Leandra Mangieri, PhD; Canjun Zhu, PhD; Zhiying Jiang, PhD; Xugen Huang, PhD; and Nicholas Justice, PhD. Also contributing to the paper were Yong Xu, MD, PhD, and Benjamin Arenkiel, PhD, of Baylor College of Medicine.
Read more at Science Daily
The scientists believe their research could aid efforts to develop treatments for a serious eating disorder called anorexia nervosa, which has the highest mortality rate of any mental disorder, according to the National Institute of Mental Health. People with anorexia nervosa avoid food, severely restrict food, or eat very small quantities of only certain foods. Even when they are dangerously underweight, they may see themselves as overweight.
"We have identified a part of the brain in a mouse model that controls the impact of emotions on eating," said Qingchun Tong, PhD, the study's senior author and an associate professor in the Center for Metabolic and Degenerative Disease at McGovern Medical School at UTHealth.
Because mice and humans have similar nervous systems, Tong, the Cullen Chair in Molecular Medicine at UTHealth, believes their findings could shed light on the part of the human brain that regulates hunger.
The investigators believe they are among the first to demonstrate the role of this neurocircuit in the regulation of both stress and hunger.
While previous research has established that stress can both reduce and increase a person's desire to eat, the neural mechanisms that act on the regulation of eating by stress-related responses largely remain a mystery.
Tong's team focused on a neurocircuit connecting two parts of the mouse brain: the paraventricular hypothalamus, an eating-related zone in the brain, and the ventral lateral septum, an emotional zone in the brain. The neurocircuit acts as an on/off switch.
When researchers activated the neurocircuit, there was an increase in anxiety levels and a decrease in appetite. Conversely, when the investigators inhibited the neurocircuit, anxiety levels dropped and hunger increased.
The scientists used a research technique called optogenetics to turn the neurons in question on and off.
Yuanzhong Xu, PhD, the study's lead author and an instructor at McGovern Medical School, said additional preclinical tests are needed to confirm their findings.
Coauthors from UTHealth include Yungang Lu, PhD; Ryan Cassidy; Leandra Mangieri, PhD; Canjun Zhu, PhD; Zhiying Jiang, PhD; Xugen Huang, PhD; and Nicholas Justice, PhD. Also contributing to the paper were Yong Xu, MD, PhD, and Benjamin Arenkiel, PhD, of Baylor College of Medicine.
Read more at Science Daily
Aug 16, 2019
Ancient feces reveal how 'marsh diet' left Bronze Age Fen folk infected with parasites
New research published today in the journal Parasitology shows how the prehistoric inhabitants of a settlement in the freshwater marshes of eastern England were infected by intestinal worms caught from foraging for food in the lakes and waterways around their homes.
The Bronze Age settlement at Must Farm, located near what is now the fenland city of Peterborough, consisted of wooden houses built on stilts above the water. Wooden causeways connected islands in the marsh, and dugout canoes were used to travel along water channels.
The village burnt down in a catastrophic fire around 3,000 years ago, with artefacts from the houses preserved in mud below the waterline, including food, cloth, and jewellery. The site has been called "Britain's Pompeii."
Also preserved in the surrounding mud were waterlogged "coprolites" -- pieces of human faeces -- that have now been collected and analysed by archaeologists at the University of Cambridge. They used microscopy techniques to detect ancient parasite eggs within the faeces and surrounding sediment.
Very little is known about the intestinal diseases of Bronze Age Britain. The one previous study, of a farming village in Somerset, found evidence of roundworm and whipworm: parasites spread through contamination of food by human faeces.
The ancient excrement of the Anglian marshes tells a different story. "We have found the earliest evidence for fish tapeworm, Echinostoma worm, and giant kidney worm in Britain," said study lead author Dr Piers Mitchell of Cambridge's Department of Archaeology.
"These parasites are spread by eating raw aquatic animals such as fish, amphibians and molluscs. Living over slow-moving water may have protected the inhabitants from some parasites, but put them at risk of others if they ate fish or frogs."
Disposal of human and animal waste into the water around the settlement likely prevented direct faecal pollution of the fenlanders' food, and so prevented infection from roundworm -- the eggs of which have been found at Bronze Age sites across Europe.
However, water in the fens would have been quite stagnant, due in part to thick reed beds, leaving waste accumulating in the surrounding channels. Researchers say this likely provided fertile ground for other parasites to infect local wildlife, which -- if eaten raw or poorly cooked -- then spread to village residents.
"The dumping of excrement into the freshwater channel in which the settlement was built, and consumption of aquatic organisms from the surrounding area, created an ideal nexus for infection with various species of intestinal parasite," said study first author Marissa Ledger, also from Cambridge's Department of Archaeology.
Fish tapeworms can reach 10m in length, and live coiled up in the intestines. Heavy infection can lead to anemia. Giant kidney worms can reach up to a metre in length. They gradually destroy the organ as they become larger, leading to kidney failure. Echinostoma worms are much smaller, up to 1cm in length. Heavy infection can lead to inflammation of the intestinal lining.
"As writing was only introduced to Britain centuries later with the Romans, these people were unable to record what happened to them during their lives. This research enables us for the first time to clearly understand the infectious diseases experienced by prehistoric people living in the Fens," said Ledger.
The Cambridge team worked with colleagues at the University of Bristol's Organic Chemistry Unit to determine whether coprolites excavated from around the houses were human or animal. While some were human, others were from dogs.
"Both humans and dogs were infected by similar parasitic worms, which suggests the humans were sharing their food or leftovers with their dogs," said Ledger.
Other parasites that infect animals were also found at the site, including pig whipworm and Capillaria worm. It is thought that they originated from the butchery and consumption of the intestines of farmed or hunted animals, but probably did not cause humans any harm.
The researchers compared their latest data with previous studies on ancient parasites from both the Bronze Age and Neolithic. Must Farm tallies with the trend of fewer parasite species found at Bronze Age compared with Neolithic sites.
"Our study fits with the broader pattern of a shrinking of the parasite ecosystem through time," said Mitchell. "Changes in diet, sanitation and human-animal relationships over millennia have affected rates of parasitic infection." Although he points out that infections from the fish tapeworm found at Must Farm have seen a recent resurgence due to the popularity of sushi, smoked salmon and ceviche.
Read more at Science Daily
The Bronze Age settlement at Must Farm, located near what is now the fenland city of Peterborough, consisted of wooden houses built on stilts above the water. Wooden causeways connected islands in the marsh, and dugout canoes were used to travel along water channels.
The village burnt down in a catastrophic fire around 3,000 years ago, with artefacts from the houses preserved in mud below the waterline, including food, cloth, and jewellery. The site has been called "Britain's Pompeii."
Also preserved in the surrounding mud were waterlogged "coprolites" -- pieces of human faeces -- that have now been collected and analysed by archaeologists at the University of Cambridge. They used microscopy techniques to detect ancient parasite eggs within the faeces and surrounding sediment.
Very little is known about the intestinal diseases of Bronze Age Britain. The one previous study, of a farming village in Somerset, found evidence of roundworm and whipworm: parasites spread through contamination of food by human faeces.
The ancient excrement of the Anglian marshes tells a different story. "We have found the earliest evidence for fish tapeworm, Echinostoma worm, and giant kidney worm in Britain," said study lead author Dr Piers Mitchell of Cambridge's Department of Archaeology.
"These parasites are spread by eating raw aquatic animals such as fish, amphibians and molluscs. Living over slow-moving water may have protected the inhabitants from some parasites, but put them at risk of others if they ate fish or frogs."
Disposal of human and animal waste into the water around the settlement likely prevented direct faecal pollution of the fenlanders' food, and so prevented infection from roundworm -- the eggs of which have been found at Bronze Age sites across Europe.
However, water in the fens would have been quite stagnant, due in part to thick reed beds, leaving waste accumulating in the surrounding channels. Researchers say this likely provided fertile ground for other parasites to infect local wildlife, which -- if eaten raw or poorly cooked -- then spread to village residents.
"The dumping of excrement into the freshwater channel in which the settlement was built, and consumption of aquatic organisms from the surrounding area, created an ideal nexus for infection with various species of intestinal parasite," said study first author Marissa Ledger, also from Cambridge's Department of Archaeology.
Fish tapeworms can reach 10m in length, and live coiled up in the intestines. Heavy infection can lead to anemia. Giant kidney worms can reach up to a metre in length. They gradually destroy the organ as they become larger, leading to kidney failure. Echinostoma worms are much smaller, up to 1cm in length. Heavy infection can lead to inflammation of the intestinal lining.
"As writing was only introduced to Britain centuries later with the Romans, these people were unable to record what happened to them during their lives. This research enables us for the first time to clearly understand the infectious diseases experienced by prehistoric people living in the Fens," said Ledger.
The Cambridge team worked with colleagues at the University of Bristol's Organic Chemistry Unit to determine whether coprolites excavated from around the houses were human or animal. While some were human, others were from dogs.
"Both humans and dogs were infected by similar parasitic worms, which suggests the humans were sharing their food or leftovers with their dogs," said Ledger.
Other parasites that infect animals were also found at the site, including pig whipworm and Capillaria worm. It is thought that they originated from the butchery and consumption of the intestines of farmed or hunted animals, but probably did not cause humans any harm.
The researchers compared their latest data with previous studies on ancient parasites from both the Bronze Age and Neolithic. Must Farm tallies with the trend of fewer parasite species found at Bronze Age compared with Neolithic sites.
"Our study fits with the broader pattern of a shrinking of the parasite ecosystem through time," said Mitchell. "Changes in diet, sanitation and human-animal relationships over millennia have affected rates of parasitic infection." Although he points out that infections from the fish tapeworm found at Must Farm have seen a recent resurgence due to the popularity of sushi, smoked salmon and ceviche.
Read more at Science Daily
Discovery of a bottleneck relief in photosynthesis may have a major impact on food crops
Scientists have found how to relieve a bottleneck in the process by which plants transform sunlight into food, which may lead to an increase in crop production. They discovered that producing more of a protein that controls the rate in which electrons flow during photosynthesis, accelerates the whole process.
"We tested the effect of increasing the production of the Rieske FeS protein, and found it increases photosynthesis by 10 percent," said lead researcher Dr Maria Ermakova from the ARC Centre of Excellence for Translational Photosynthesis (CoETP).
"The Rieske FeS protein belongs to a complex which is like a hose through which electrons flow, so the energy can be used by the carbon engine of the plant. By overexpressing this protein, we have discovered how to release the pressure of the hose, so more electrons can flow, accelerating the photosynthetic process," said Dr Ermakova, who works at The Australian National University (ANU) Centre Node.
Dr Ermakova, the lead author of the paper published this week in the journal Communications Biology, said that this is the first time that scientists have generated more of the Rieske FeS protein inside plants that use the C4 photosynthesis pathway.
Until now, the majority of efforts to improve photosynthesis have been done in species that use C3 photosynthesis, such as wheat and rice, but not a lot has been done in enhancing C4 photosynthesis.
This is despite the fact that C4 crop species -- like maize and sorghum -- play a key role in world agriculture, and are already some of the most productive crops in the world.
"These results demonstrate that changing the rate of electron transport enhances photosynthesis in the C4 model species, Setaria viridis, a close relative of maize and sorghum. It is an important proof of concept that helps us enormously to understand more about how C4 photosynthesis works," said CoETP's Deputy Director Professor Susanne von Caemmerer, one of the co-authors of this study.
The Rieske protein is particularly important in environments with high radiance, where C4 plants grow. Previous research has shown that overexpressing the Rieske protein in C3 plants improves photosynthesis, but more research was needed in C4 plants.
"It is really exciting, as we are now ready to transform this into sorghum and test the effect it has on biomass in a food crop," Professor von Caemmerer says.
The research is the result of an international collaboration with researchers from the University of Essex in the UK, who are part of the Realizing Increased Photosynthetic Efficiency (RIPE) project.
"This is a great example that we need international collaborations to solve the complex challenges faced in trying to improve crop production," said University of Essex researcher Patricia Lopez-Calcagno, who was involved in producing some of the essential genetic components for the plant transformation.
"In the last 30 years, we have learnt a lot about how C4 plants work by making them worse -- by breaking them as part of the process of discovery. However, this is the first example in which we have actually improved the plants," says Professor Robert Furbank, Director of the ARC Centre of Excellence for Translational Photosynthesis and one of the authors of the study.
"Our next steps are to assemble the whole protein FeS complex, which has many other components. There is a lot more to do and lots of things about this protein complex we still don't understand. We have reached 10 percent enhancement by overexpressing the Rieske FeS component, but we know we can do better than that," says Professor Furbank.
Read more at Science Daily
"We tested the effect of increasing the production of the Rieske FeS protein, and found it increases photosynthesis by 10 percent," said lead researcher Dr Maria Ermakova from the ARC Centre of Excellence for Translational Photosynthesis (CoETP).
"The Rieske FeS protein belongs to a complex which is like a hose through which electrons flow, so the energy can be used by the carbon engine of the plant. By overexpressing this protein, we have discovered how to release the pressure of the hose, so more electrons can flow, accelerating the photosynthetic process," said Dr Ermakova, who works at The Australian National University (ANU) Centre Node.
Dr Ermakova, the lead author of the paper published this week in the journal Communications Biology, said that this is the first time that scientists have generated more of the Rieske FeS protein inside plants that use the C4 photosynthesis pathway.
Until now, the majority of efforts to improve photosynthesis have been done in species that use C3 photosynthesis, such as wheat and rice, but not a lot has been done in enhancing C4 photosynthesis.
This is despite the fact that C4 crop species -- like maize and sorghum -- play a key role in world agriculture, and are already some of the most productive crops in the world.
"These results demonstrate that changing the rate of electron transport enhances photosynthesis in the C4 model species, Setaria viridis, a close relative of maize and sorghum. It is an important proof of concept that helps us enormously to understand more about how C4 photosynthesis works," said CoETP's Deputy Director Professor Susanne von Caemmerer, one of the co-authors of this study.
The Rieske protein is particularly important in environments with high radiance, where C4 plants grow. Previous research has shown that overexpressing the Rieske protein in C3 plants improves photosynthesis, but more research was needed in C4 plants.
"It is really exciting, as we are now ready to transform this into sorghum and test the effect it has on biomass in a food crop," Professor von Caemmerer says.
The research is the result of an international collaboration with researchers from the University of Essex in the UK, who are part of the Realizing Increased Photosynthetic Efficiency (RIPE) project.
"This is a great example that we need international collaborations to solve the complex challenges faced in trying to improve crop production," said University of Essex researcher Patricia Lopez-Calcagno, who was involved in producing some of the essential genetic components for the plant transformation.
"In the last 30 years, we have learnt a lot about how C4 plants work by making them worse -- by breaking them as part of the process of discovery. However, this is the first example in which we have actually improved the plants," says Professor Robert Furbank, Director of the ARC Centre of Excellence for Translational Photosynthesis and one of the authors of the study.
"Our next steps are to assemble the whole protein FeS complex, which has many other components. There is a lot more to do and lots of things about this protein complex we still don't understand. We have reached 10 percent enhancement by overexpressing the Rieske FeS component, but we know we can do better than that," says Professor Furbank.
Read more at Science Daily
Best of both worlds: Asteroids and massive mergers
The race is on. Since the construction of technology able to detect the ripples in space and time triggered by collisions from massive objects in the universe, astronomers around the world have been searching for the bursts of light that could accompany such collisions, which are thought to be the sources of rare heavy elements.
The University of Arizona's Steward Observatory has partnered with the Catalina Sky Survey, which searches for near-Earth asteroids from atop Mount Lemmon, in an effort dubbed Searches after Gravitational Waves Using ARizona Observatories, or SAGUARO, to find optical counterparts to massive mergers.
"Catalina Sky Survey has all of this infrastructure for their asteroid survey. So we have deployed additional software to take gravitational wave alerts from LIGO (the Laser Interferometer Gravitational-Wave Observatory) and the Virgo interferometer then notify the survey to search an area of sky most likely to contain the optical counterpart," said Michael Lundquist, postdoctoral research associate and lead author on the study published today in the Astrophysical Journal Letters.
"Essentially, instead of searching the next section of sky that we would normally, we go off and observe some other area that has a higher probability of containing an optical counterpart of a gravitational wave event," said Eric Christensen, Catalina Sky Survey director and Lunar and Planetary Laboratory senior staff scientist. "The main idea is we can run this system while still maintaining the asteroid search."
The ongoing campaign began in April, and in that month alone, the team was notified of three massive collisions. Because it is difficult to tell the precise location from which the gravitational wave originated, locating optical counterparts can be difficult.
According to Lundquist, two strategies are being employed. In the first, teams with small telescopes target galaxies that are at the right approximate distance, according to the gravitational wave signal. Catalina Sky Survey, on the other hand, utilizes a 60-inch telescope with a wide field of view to scan large swaths of sky in 30 minutes.
Three alerts, on April 9, 25 and 26, triggered the team's software to search nearly 20,000 objects. Machine learning software then trimmed down the total number of potential optical counterparts to five.
The first gravitational wave event was a merger of two black holes, Lundquist said.
"There are some people who think you can get an optical counterpart to those, but it's definitely inconclusive," he said.
The second event was a merger of two neutron stars, the incredibly dense core of a collapsed giant star. The third is thought to be a merger between a neutron star and a black hole, Lundquist said.
While no teams confirmed optical counterparts, the UA team did find several supernovae. They also used the Large Binocular Telescope Observatory to spectroscopically classify one promising target from another group. It was determined to be a supernova and not associated with the gravitational wave event.
"We also found a near-Earth object in the search field on April 25," Christensen said. "That proves right there we can do both things at the same time."
They were able to do this because Catalina Sky Survey has observations of the same swaths of sky going back many years. Many other groups don't have easy access to past photos for comparison, offering the UA team a leg up.
"We have really nice references," Lundquist said. "We subtract the new image from the old image and use that difference to look for anything new in the sky."
"The process Michael described," Christensen said, "starting with a large number of candidate detections and filtering down to whatever the true detections are, is very familiar. We do that with near-Earth objects, as well."
The team is planning on deploying a second telescope in the hunt for optical counterparts: Catalina Sky Survey's 0.7-meter Schmidt telescope. While the telescope is smaller than the 60-inch telescope, it has an even wider field of view, which allows astronomers to quickly search an even larger chunk of sky. They've also improved their machine learning software to filter out stars that regularly change in brightness.
Read more at Science Daily
The University of Arizona's Steward Observatory has partnered with the Catalina Sky Survey, which searches for near-Earth asteroids from atop Mount Lemmon, in an effort dubbed Searches after Gravitational Waves Using ARizona Observatories, or SAGUARO, to find optical counterparts to massive mergers.
"Catalina Sky Survey has all of this infrastructure for their asteroid survey. So we have deployed additional software to take gravitational wave alerts from LIGO (the Laser Interferometer Gravitational-Wave Observatory) and the Virgo interferometer then notify the survey to search an area of sky most likely to contain the optical counterpart," said Michael Lundquist, postdoctoral research associate and lead author on the study published today in the Astrophysical Journal Letters.
"Essentially, instead of searching the next section of sky that we would normally, we go off and observe some other area that has a higher probability of containing an optical counterpart of a gravitational wave event," said Eric Christensen, Catalina Sky Survey director and Lunar and Planetary Laboratory senior staff scientist. "The main idea is we can run this system while still maintaining the asteroid search."
The ongoing campaign began in April, and in that month alone, the team was notified of three massive collisions. Because it is difficult to tell the precise location from which the gravitational wave originated, locating optical counterparts can be difficult.
According to Lundquist, two strategies are being employed. In the first, teams with small telescopes target galaxies that are at the right approximate distance, according to the gravitational wave signal. Catalina Sky Survey, on the other hand, utilizes a 60-inch telescope with a wide field of view to scan large swaths of sky in 30 minutes.
Three alerts, on April 9, 25 and 26, triggered the team's software to search nearly 20,000 objects. Machine learning software then trimmed down the total number of potential optical counterparts to five.
The first gravitational wave event was a merger of two black holes, Lundquist said.
"There are some people who think you can get an optical counterpart to those, but it's definitely inconclusive," he said.
The second event was a merger of two neutron stars, the incredibly dense core of a collapsed giant star. The third is thought to be a merger between a neutron star and a black hole, Lundquist said.
While no teams confirmed optical counterparts, the UA team did find several supernovae. They also used the Large Binocular Telescope Observatory to spectroscopically classify one promising target from another group. It was determined to be a supernova and not associated with the gravitational wave event.
"We also found a near-Earth object in the search field on April 25," Christensen said. "That proves right there we can do both things at the same time."
They were able to do this because Catalina Sky Survey has observations of the same swaths of sky going back many years. Many other groups don't have easy access to past photos for comparison, offering the UA team a leg up.
"We have really nice references," Lundquist said. "We subtract the new image from the old image and use that difference to look for anything new in the sky."
"The process Michael described," Christensen said, "starting with a large number of candidate detections and filtering down to whatever the true detections are, is very familiar. We do that with near-Earth objects, as well."
The team is planning on deploying a second telescope in the hunt for optical counterparts: Catalina Sky Survey's 0.7-meter Schmidt telescope. While the telescope is smaller than the 60-inch telescope, it has an even wider field of view, which allows astronomers to quickly search an even larger chunk of sky. They've also improved their machine learning software to filter out stars that regularly change in brightness.
Read more at Science Daily
How E. coli knows how to cause the worst possible infection
A pair of University of Virginia School of Medicine scientists have revealed how E. coli seeks out the most oxygen-free crevices of your colon to cause the worst infection possible. The discovery could one day let doctors prevent the infection by allowing E. coli to pass harmlessly through the body.
The new discovery shows just how the foodborne pathogen knows where and when to begin colonizing the colon on its way to making you sick. By recognizing the low-oxygen environment of the large intestine, the dangerous bacterium gives itself the best odds of establishing a robust infection -- one that is punishing for the host.
"Bacterial pathogens typically colonize a specific tissue in the host. Therefore, as part of their infection strategies, bacterial pathogens precisely time deployment of proteins and toxins to these specific colonization niches in the human host. This allows the pathogens to save energy and avoid detection by our immune systems and ultimately cause disease," said researcher Melissa Kendall, PhD, of UVA's Department of Microbiology, Immunology and Cancer Biology. "By knowing how bacterial pathogens sense where they are in the body, we may one day be able to prevent E. coli, as well as other pathogens, from knowing where it is inside a human host and allow it to pass through the body without causing an infection."
A Bacterial Goldilocks
E. coli naturally lives in our colons, and most strains do us no harm. But there are several strains that can cause cramps, diarrhea, vomiting, even kidney failure and death. Children are at particular risk. As such, E. coli outbreaks appear periodically in the news. In July, for example, people in several states were sickened by E. coli linked to ground bison meat.
Kendall and graduate student Elizabeth M. Melson have shed important light on how harmful E. coli infections establish themselves in the body. The researchers outlined a process the bacteria use to detect low oxygen levels in the large intestine and then produce proteins that allow E. coli to attach to host cells and establish infection.
Oxygen actually diffuses from the intestinal tissue into the gut, and there are comparably higher levels in the small intestine than the large. E. coli specifically waits until it has reached the-low oxygen large intestine before striking.
E. coli's vital asset is a small form of RNA that activates particular genes when oxygen levels are low enough, the researchers reveal. It's at this point that the infection really gets established. Thanks to this natural sensing process, the bacteria are able to establish infection and begin to manufacture harmful Shiga toxins.
The researchers believe that other bacterial pathogens, such as Shigella and Salmonella, likely employ a similar control mechanism, though more work needs to be done to establish that.
Read more at Science Daily
The new discovery shows just how the foodborne pathogen knows where and when to begin colonizing the colon on its way to making you sick. By recognizing the low-oxygen environment of the large intestine, the dangerous bacterium gives itself the best odds of establishing a robust infection -- one that is punishing for the host.
"Bacterial pathogens typically colonize a specific tissue in the host. Therefore, as part of their infection strategies, bacterial pathogens precisely time deployment of proteins and toxins to these specific colonization niches in the human host. This allows the pathogens to save energy and avoid detection by our immune systems and ultimately cause disease," said researcher Melissa Kendall, PhD, of UVA's Department of Microbiology, Immunology and Cancer Biology. "By knowing how bacterial pathogens sense where they are in the body, we may one day be able to prevent E. coli, as well as other pathogens, from knowing where it is inside a human host and allow it to pass through the body without causing an infection."
A Bacterial Goldilocks
E. coli naturally lives in our colons, and most strains do us no harm. But there are several strains that can cause cramps, diarrhea, vomiting, even kidney failure and death. Children are at particular risk. As such, E. coli outbreaks appear periodically in the news. In July, for example, people in several states were sickened by E. coli linked to ground bison meat.
Kendall and graduate student Elizabeth M. Melson have shed important light on how harmful E. coli infections establish themselves in the body. The researchers outlined a process the bacteria use to detect low oxygen levels in the large intestine and then produce proteins that allow E. coli to attach to host cells and establish infection.
Oxygen actually diffuses from the intestinal tissue into the gut, and there are comparably higher levels in the small intestine than the large. E. coli specifically waits until it has reached the-low oxygen large intestine before striking.
E. coli's vital asset is a small form of RNA that activates particular genes when oxygen levels are low enough, the researchers reveal. It's at this point that the infection really gets established. Thanks to this natural sensing process, the bacteria are able to establish infection and begin to manufacture harmful Shiga toxins.
The researchers believe that other bacterial pathogens, such as Shigella and Salmonella, likely employ a similar control mechanism, though more work needs to be done to establish that.
Read more at Science Daily
Aug 15, 2019
July 2019 was hottest month on record for the planet
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| Thermometer showing high temperature in summer |
Here's a closer look into NOAA's latest monthly global climate report:
Climate by the numbers: July 2019
The average global temperature in July was 1.71 degrees F above the 20th-century average of 60.4 degrees, making it the hottest July in the 140-year record, according to scientists at NOAA's National Centers for Environmental Information. The previous hottest month on record was July 2016.
Nine of the 10 hottest Julys have occurred since 2005 -- with the last five years ranking as the five hottest. Last month was also the 43rd consecutive July and 415th consecutive month with above-average global temperatures.
Year to date: January through July
The period from January through July produced a global temperature that was 1.71 degrees F above the 20th-century average of 56.9 degrees, tying with 2017 as the second-hottest year to date on record.
It was the hottest year to date for parts of North and South America, Asia, Australia, New Zealand, the southern half of Africa, portions of the western Pacific Ocean, western Indian Ocean and the Atlantic Ocean.
More notable stats and facts
Record-low sea ice: Average Arctic sea ice set a record low for July, running 19.8% below average -- surpassing the previous historic low of July 2012.
Average Antarctic sea-ice coverage was 4.3% below the 1981-2010 average, making it the smallest for July in the 41-year record.
Some cool spots: Parts of Scandinavia and western and eastern Russia had temperatures at least 2.7 degrees F below average.
NOAA's full climate report is available at: https://www.ncdc.noaa.gov/sotc/global/201907
From Science Daily
Moon glows brighter than sun in images from NASA's Fermi
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| These images show the steadily improving view of the Moon’s gamma-ray glow from NASA’s Fermi Gamma-ray Space Telescope. Each 5-by-5-degree image is centered on the Moon and shows gamma rays with energies above 31 million electron volts, or tens of millions of times that of visible light. At these energies, the Moon is actually brighter than the Sun. Brighter colors indicate greater numbers of gamma rays. This image sequence shows how longer exposure, ranging from two to 128 months (10.7 years), improved the view. |
Gamma-ray observations are not sensitive enough to clearly see the shape of the Moon's disk or any surface features. Instead, Fermi's Large Area Telescope (LAT) detects a prominent glow centered on the Moon's position in the sky.
Mario Nicola Mazziotta and Francesco Loparco, both at Italy's National Institute of Nuclear Physics in Bari, have been analyzing the Moon's gamma-ray glow as a way of better understanding another type of radiation from space: fast-moving particles called cosmic rays.
"Cosmic rays are mostly protons accelerated by some of the most energetic phenomena in the universe, like the blast waves of exploding stars and jets produced when matter falls into black holes," explained Mazziotta.
Because the particles are electrically charged, they're strongly affected by magnetic fields, which the Moon lacks. As a result, even low-energy cosmic rays can reach the surface, turning the Moon into a handy space-based particle detector. When cosmic rays strike, they interact with the powdery surface of the Moon, called the regolith, to produce gamma-ray emission. The Moon absorbs most of these gamma rays, but some of them escape.
Mazziotta and Loparco analyzed Fermi LAT lunar observations to show how the view has improved during the mission. They rounded up data for gamma rays with energies above 31 million electron volts -- more than 10 million times greater than the energy of visible light -- and organized them over time, showing how longer exposures improve the view.
"Seen at these energies, the Moon would never go through its monthly cycle of phases and would always look full," said Loparco.
As NASA sets its sights on sending humans to the Moon by 2024 through the Artemis program, with the eventual goal of sending astronauts to Mars, understanding various aspects of the lunar environment take on new importance. These gamma-ray observations are a reminder that astronauts on the Moon will require protection from the same cosmic rays that produce this high-energy gamma radiation.
While the Moon's gamma-ray glow is surprising and impressive, the Sun does shine brighter in gamma rays with energies higher than 1 billion electron volts. Cosmic rays with lower energies do not reach the Sun because its powerful magnetic field screens them out. But much more energetic cosmic rays can penetrate this magnetic shield and strike the Sun's denser atmosphere, producing gamma rays that can reach Fermi.
Read more at Science Daily
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