Culture

Every species in nature is equipped with a strategy to survive in response to danger. Plants, too, have innate systems that are triggered in response to threats, such as insects feeding on them. For example, some plants can recognize "herbivore danger signals" (HDS), which are specific chemicals in oral secretions of insects. This activates a cascade of events in the plant's physiological defense machinery, which leads to the plant developing "immunity" against the predator. However, despite considerable research, exactly how plants recognize these signals has remained a bit of a mystery. In a new study, a team of scientists from Tokyo University of Science, led by Prof Gen-ichiro Arimura, attempts to shed light on exactly how plant HDS systems work.

Some people are more sensitive than others - and around half of these differences can be attributed to our genes, new research has found.

The study, led by Queen Mary University of London, compared pairs of identical and non-identical 17-year-old twins to see how strongly they were affected by positive or negative experiences - their 'sensitivity' level. The aim was to tease out how much of the differences in sensitivity could be explained by either genetic or environmental factors during development: nature or nurture.

Twins who are brought up together will mostly experience the same environment. But only identical twins share the same genes: non-identical twins are like any other sibling. If identical twins show no more similarity in their levels of sensitivity than non-identical twins, then genes are unlikely to play a role.

Using this type of analysis, the team found that 47 percent of the differences in sensitivity between individuals were down to genetics, leaving 53 percent accounted for by environmental factors. The research, from Queen Mary University of London and Kings College London, is the first to show this link conclusively in such a large study. The findings are published in Molecular Psychiatry.

Michael Pluess, Professor of Developmental Psychology at Queen Mary University of London and study lead, said: "We are all affected by what we experience - sensitivity is something we all share as a basic human trait. But we also differ in how much of an impact our experiences have on us. Scientists have always thought there was a genetic basis for sensitivity, but this is the first time we've been able to actually quantify how much of these differences in sensitivity are explained by genetic factors."

Over 2800 twins were involved in the study, split between around 1000 identical twins and 1800 non-identical twins, roughly half of whom were same sex. The twins were asked to fill out a questionnaire, developed by Professor Pluess, which has been widely used to test an individual's levels of sensitivity to their environment This test will be made available online later this month so anyone can assess their own sensitivity.

The questionnaire is also able to tease out different types of sensitivity - whether someone is more sensitive to negative experiences or positive experiences - as well as general sensitivity. The analysis by the team suggested that these different sensitivities also have a genetic basis.

Co-researcher Dr Elham Assary said: "If a child is more sensitive to negative experiences, it may be that they become more easily stressed and anxious in challenging situations. On the other hand, if a child has a higher sensitivity to positive experiences, it may be that they are more responsive to good parenting or benefit more from psychological interventions at school. What our study shows is that these different aspects of sensitivity all have a genetic basis."

Finally, the team explored how sensitivity to other common and established personality traits, known as the 'Big Five': openness, conscientiousness, agreeableness, extraversion and neuroticism. They found that there was a shared genetic component between sensitivity, neuroticism and extraversion, but not with any of the other personality traits.

Professor Pluess believes the findings could help us in how we understand and handle sensitivity, in ourselves and others.

"We know from previous research that around a third of people are at the higher end of the sensitivity spectrum. They are generally more strongly affected by their experiences," he said. "This can have both advantages and disadvantages. Because we now know that this sensitivity is as much due to biology as environment, it is important for people to accept their sensitivity as an important part of who they are and consider it as a strength not just as a weakness."

More than 110 million years ago, a lumbering 1,300-kilogram, armour-plated dinosaur ate its last meal, died, and was washed out to sea in what is now northern Alberta. This ancient beast then sank onto its thorny back, churning up mud in the seabed that entombed it--until its fossilized body was discovered in a mine near Fort McMurray in 2011.

Since then, researchers at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alta., Brandon University, and the University of Saskatchewan (USask) have been working to unlock the extremely well-preserved nodosaur's many secrets--including what this large armoured dinosaur (a type of ankylosaur) actually ate for its last meal.

"The finding of the actual preserved stomach contents from a dinosaur is extraordinarily rare, and this stomach recovered from the mummified nodosaur by the museum team is by far the best-preserved dinosaur stomach ever found to date," said USask geologist Jim Basinger, a member of the team that analyzed the dinosaur's stomach contents, a distinct mass about the size of a soccer ball.

"When people see this stunning fossil and are told that we know what its last meal was because its stomach was so well preserved inside the skeleton, it will almost bring the beast back to life for them, providing a glimpse of how the animal actually carried out its daily activities, where it lived, and what its preferred food was."

There has been lots of speculation about what dinosaurs ate, but very little known. In a just-published article in Royal Society Open Science, the team led by Royal Tyrrell Museum palaeontologist Caleb Brown and Brandon University biologist David Greenwood provides detailed and definitive evidence of the diet of large, plant-eating dinosaurs--something that has not been known conclusively for any herbivorous dinosaur until now.

"This new study changes what we know about the diet of large herbivorous dinosaurs," said Brown. "Our findings are also remarkable for what they can tell us about the animal's interaction with its environment, details we don't usually get just from the dinosaur skeleton."

Previous studies had shown evidence of seeds and twigs in the gut but these studies offered no information as to the kinds of plants that had been eaten. While tooth and jaw shape, plant availability and digestibility have fuelled considerable speculation, the specific plants herbivorous dinosaurs consumed has been largely a mystery.

So what was the last meal of Borealopelta markmitchelli (which means "northern shield" and recognizes Mark Mitchell, the museum technician who spent more than five years carefully exposing the skin and bones of the dinosaur from the fossilized marine rock)?

"The last meal of our dinosaur was mostly fern leaves--88 per cent chewed leaf material and seven per cent stems and twigs," said Greenwood, who is also a USask adjunct professor.

"When we examined thin sections of the stomach contents under a microscope, we were shocked to see beautifully preserved and concentrated plant material. In marine rocks we almost never see such superb preservation of leaves, including the microscopic, spore-producing sporangia of ferns."

Team members Basinger, Greenwood and Brandon University graduate student Jessica Kalyniuk compared the stomach contents with food plants known to be available from the study of fossil leaves from the same period in the region. They found that the dinosaur was a picky eater, choosing to eat particular ferns (leptosporangiate, the largest group of ferns today) over others, and not eating many cycad and conifer leaves common to the Early Cretaceous landscape.

Specifically, the team identified 48 palynomorphs (microfossils like pollen and spores) including moss or liverwort, 26 clubmosses and ferns, 13 gymnosperms (mostly conifers), and two angiosperms (flowering plants).

"Also, there is considerable charcoal in the stomach from burnt plant fragments, indicating that the animal was browsing in a recently burned area and was taking advantage of a recent fire and the flush of ferns that frequently emerges on a burned landscape," said Greenwood.

"This adaptation to a fire ecology is new information. Like large herbivores alive today such as moose and deer, and elephants in Africa, these nodosaurs by their feeding would have shaped the vegetation on the landscape, possibly maintaining more open areas by their grazing."

The team also found gastroliths, or gizzard stones, generally swallowed by animals such as herbivorous dinosaurs and today's birds such as geese to aid digestion.

"We also know that based on how well-preserved both the plant fragments and animal itself are, the animal's death and burial must have followed shortly after the last meal," said Brown. "Plants give us a much better idea of season than animals, and they indicate that the last meal and the animal's death and burial all happened in the late spring to mid-summer."

"Taken together, these findings enable us to make inferences about the ecology of the animal, including how selective it was in choosing which plants to eat and how it may have exploited forest fire regrowth. It will also assist in understanding of dinosaur digestion and physiology."

Borealopelta markmitchelli, discovered during mining operations at the Suncor Millennium open pit mine north of Fort McMurray, has been on display at the Royal Tyrrell Museum since 2017. The main chunk of the stomach mass is on display with the skeleton.

Other members of the team include museum scientists Donald Henderson and Dennis Braman, and Brandon University research associate and USask alumna Cathy Greenwood.

Research continues on Borealopelta markmitchelli--the best fossil of a nodosaur ever found--to learn more about its environment and behaviour while it was alive. Student Kalyniuk is currently expanding her work on fossil plants of this age to better understand the composition of the forests in which it lived. Many of the fossils she will examine are in Basinger' collections at USask.

Researchers at Mount Sinai have discovered that human acute myeloid leukemia (AML) stem cells are dependent on a transcription factor known as RUNX1, potentially providing a new therapeutic target to achieve lasting remissions or even cures for a disease in which medical advances have been limited.

In a study published in June in Cell Reports, the team described how they used induced pluripotent stem cells from a patient with AML to recreate leukemia stem cell biology in the lab, revealing that AML leukemia stem cells lose their leukemic properties once the transcription factor is knocked down or deleted. The researchers further showed that AML cells from other patients were RUNX1-dependent.

"Our development of a new leukemia stem cell model for AML allowed us to study these cells in greater detail than ever before, leading to the unexpected finding of specific dependency of leukemia stem cells on the transcription factor RUNX1," says Eirini Papapetrou, MD, PhD, Associate Professor, Oncological Sciences, at Icahn School of Medicine at Mount Sinai, and senior author of the study. "Digging further, we found earlier studies suggesting that RUNX1 expression is a marker of poor prognosis for patients with acute myeloid leukemia. Our work may now provide an explanation, namely that RUNX1 is required to sustain leukemia stem cells and thus propagate the leukemia."

Acute myeloid leukemia is a cancer of the blood and bone marrow, the spongy tissue inside bones where blood cells are made. AML, which primarily affects white blood cells, is one of the most common leukemias in adults, with more than 20,000 newly diagnosed cases each year in the United States. While several new drugs have been introduced in recent years targeting the disease, they have fallen short of significantly changing patient outcomes or survival.

Dr. Papapetrou was one of the first investigators to derive patient-specific induced pluripotent stem cells and use them in disease modeling, with the goal of better understanding the mechanisms of acute myeloid leukemia and identifying promising new therapeutic targets. Induced pluripotent stem cells, which won their developer the Nobel Prize in 2012, are generated from adult cells and can be differentiated into almost any type of cell type in the body, making them different from and in some ways preferable to embryonic stem cells. Through the use of induced pluripotent stem cells, Dr. Papapetrou and her research team were able to recapitulate a leukemia stem cell state that was difficult to capture and study with traditional models. "Our model made it much easier to isolate and culture leukemia stem cells over a long period, which meant we could obtain them in large numbers for ongoing research," she explains.

That work uncovered other intriguing genes that appear to play a role in the mediation of RUNX1 effects in leukemia stem cells. Most prominent is TSPAN 18, which scientists believe could prove to be an even more attractive therapeutic target than RUNX1 since, as a cell surface protein, it can be targeted with antibody or chimeric antigen receptor (CAR) T-cell approaches. TSPAN 18 and other candidate genes that lie downstream of RUNX1 could be future subjects of investigation by Dr. Papapetrou's lab, which is committed to the study of blood disorders, particularly myeloid malignancies.

Indeed, the lab's advances with human leukemia stem cells have broader implications for the entire field around therapeutic targeting of leukemia stem cells. "We're demonstrating that you can't appreciably affect leukemia without addressing leukemia stem cells," Dr. Papapetrou emphasizes, adding that her work has provided datasets and characterized gene signatures of AML leukemia stem cells that will be critical to future studies. "It's impossible to say at this early stage when or if our work will lead to significant improvements or possibly a cure for AML," she says, "but the results we've seen so far are very promising and underscore the tremendous potential in this field."

PITTSBURGH, June 2, 2020 - Using skin cells from human volunteers, researchers at the University of Pittsburgh School of Medicine have created fully functional mini livers, which they then transplanted into rats.

In this proof-of-concept experiment, the lab-made organs survived for four days inside their animal hosts. These results were published today in Cell Reports.

"Seeing that little human organ there inside the animal - brown, looking like a liver - that was pretty cool. This thing that looks like a liver and functions like a liver came from somebody's skin cells," said senior author Alejandro Soto-Gutierrez, M.D., Ph.D., associate professor of pathology at Pitt and faculty member of both the McGowan Institute for Regenerative Medicine and the Pittsburgh Liver Research Center.

These mini livers secrete bile acids and urea, just like a normal liver, except they're made-to-order in the lab using patient cells. And, although liver maturation takes up to two years in a natural environment, Soto-Gutierrez and colleagues did it in under a month.

The researchers created their mini livers by reprogramming human skin cells into stem cells, coaxing those stem cells to become various types of liver cells and, then, seeding those human liver cells into a rat liver with all of its own cells stripped out.

As an ultimate test, the researchers transplanted their lab-grown mini livers into five rats, who were bred to resist organ rejection. Four days after the transplant, researchers investigated how well the implanted organs were faring.

In all cases, blood flow problems had developed within and around the graft, but the transplanted mini livers worked - the rats had human liver proteins in their blood serum.

Soto-Gutierrez is optimistic that this research is not merely a stepping-stone on the path toward growing replacement organs in a lab, but also a useful tool in its own right.

"The long-term goal is to create organs that can replace organ donation, but in the near future, I see this as a bridge to transplant," Soto-Gutierrez said. "For instance, in acute liver failure, you might just need hepatic boost for a while instead of a whole new liver."

But there are significant challenges to overcome, he noted, including long-term survival and safety issues.

Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online today by Royal Society Open Science. The study focuses on the digital genome that uses programmable DNA-based on-off switches to change the readout of genetic information. The digital rewiring of the genome involves switch elements called flipons. Flipons fast track the evolution of multi-cellular organisms. The flipon strategy is less risky evolution based only on mutations.

Dr. Herbert says "Previously coding by DNA was described as analog. Going digital has greatly increased the genome's storage capacity. Different programs can be run by compiling the information differently."

Flipons are DNA sequences capable of adopting different DNA conformations. They act as on-off switches. Each switch alters the program read out from the DNA code. Flipon settings change with context. Each setting leads to a different set of instructions for the cell to follow. Examples of how flipons act are provided by innate immune responses and by DNA damage repair pathways. Flipon conformation determines whether or not these pathways are active.

Flipons fast track the evolution of multi-cellular organisms. They spread through the genome through a copy and paste mechanism. They work as an on-off switch to change how cells compile their operating instructions. Flipons are programmable. Organisms can optimize flipon settings by learning. Those clades that learn best survive better. They adapt and reproduce faster than their competition.

There are different classes of flipon: Z-flipons can form left-handed DNA by flipping over the bases in right handed DNA. The flip happens in active genes and helps localize RNA processing complexes to that region. T-flipons have three strands to form triplexes. They localize the RNAs needed to program a particular outcome. G-flipons are four stranded structures that initiate repair programs after DNA damage.

Flipons enable the compilation of many different messages from a single genomic sequence. They generate more diversity than is possible by mutation or by DNA rearrangements. Flipons elaborate on already successful adaptations without destroying them. The newly compiled transcripts work with the old to enhance survival.

Flipons can be programmed in many different ways. DNA modifications affect how easily they flip from an off-state to an on-state. Proteins also regulate flipon conformation. The programming requires work. Energy is traded for information. The trade-off generates a larger message space to explore and exploit. When flipons freeze in one state of the other, often disease results. Examples of Mendelian disease due to flipons are given in the paper.

The flipon strategy is less risky than other forms of evolution. Previously the focus has been on DNA mutation as the key driver of change. Mutations cause an alteration in the DNA sequence that codes for a protein. The process is random and difficult to reverse. In contrast, flipons are programmable and reversible. Flipons only change how messages are compiled from DNA. They do not alter the DNA coding sequence. They generate variability without the risks associated with mutation. Natural selection depends on variability to find the best way for an organism to survive and reproduce.

The paper focuses on the role of ALU repeat elements in the digital rewiring of the genome. These elements comprise about 11% of the human genome. They spread by a copy and paste that depends on reverse transcription onto their RNA into DNA. They are thought to account for some of the differences between human and apes. Once the invader, these ALU elements now enhance the evolution of their host.

A study in Cell Reports maps genes essential for the metabolic function of M. agalactiae and M. pneumoniae, two common bacteria that infect livestock and humans respectively.

The map of M. agalactiae reveals new insights that unlocks routes to explore new vaccines and antimicrobials for veterinary applications.

The results can also be used to finetune a re-engineered version of M. pneumoniae so that it can treat human lung diseases in the future.

The new methods used in the study are a useful tool for other researchers to quickly evaluate a microorganism's active metabolism, boosting chances of finding new applications using microbes.

Bacteria are versatile living organisms that can colonise a huge range of environments, hosts, or tissues within a host. Much of this success is thanks to their metabolic plasticity, which has been shaped by evolution over millions of years.

Microbial metabolic pathways can be exploited for industrial applications, such as using bacteria to dye jeans with their trademark indigo hue. It is also increasingly important in healthcare, with previous studies linking microbiome metabolism with the human body's ability to absorb therapeutic drugs.

Current approaches to charting microbial metabolic pathways are expensive, tedious and time consuming, hindering the development of new applications such as vaccines or antimicrobial substances. New tools are needed to build an accurate map of all the chemical reactions that take place in a particular strain of bacteria with no dead ends or futile loops.

In a study published today in the journal Cell Reports, researchers at the Centre for Genomic Regulation in Barcelona describe a new method for determining active metabolic pathways in microbes using cutting-edge techniques from genomics and proteomics.

The researchers first tested their methods by mapping the metabolic pathways of Mycoplasma pneumoniae, a bacterium with a small genome that commonly causes mild infections of the respiratory system, and whose metabolism has been comprehensively documented in the past. Its active metabolic pathways agreed with experimental data.

They then used the same methods to document the relatively unknown pathways of Mycoplasma agalactiae, a common source of infections in goats and sheep with significant health and economic ramifications for livestock. Despite M. agalactiae and M. pneumoniae sharing much of each other's genome, their metabolisms took substantially different pathways, highlighting the complexity of predicting metabolic networks based on genomic information alone.

"Microorganisms are a treasure trove for finding new applications for healthcare and industry. Having new tools to capture a global picture of the activity and directionality of microbial metabolic networks is key to making the most of these natural resources," says Ariadna Montero Blay, PhD student at the Centre for Genomic Regulation and first author of the study.

"Our findings for Mycoplasma agalactiae could have a great impact in the veterinary field in the generation of novel antimicrobials based on toxic metabolites or attenuated vaccination strains with knock-down of essential metabolic genes or re-engineered metabolic fluxes."

The results of the study may be used to finetune a re-engineered version of M. pneumoniae so that it may one day be used to treat human lung diseases, a long-term objective of the research group.

"While this is still years away, we can use these methods to identify important metabolic routes and block them, which could increase the specificity and effectiveness of using Mycoplasma as a live pill," says Luis Serrano, ICREA Research Professor, Director of the CRG and last author of the study. "Our study highlights the ingenious new methods in science that are reducing time and costs and accelerating new discoveries."

HOUSTON-(June 2, 2020) - The country's first convalescent plasma transfusion trial results have been peer-reviewed and published, showing 19 out of 25 patients improving with the treatment and 11 discharged from the hospital. On March 28, Houston Methodist became the first academic medical center in the nation to transfuse plasma from recovered COVID-19 patients into two critically ill patients.

With no adverse side effects caused by the plasma transfusion, the study concluded that convalescent plasma is a safe treatment option for patients with severe COVID-19 disease. To date, this is the largest cohort worldwide assessed for outcomes pertaining to convalescent plasma transfusion for COVID-19. The findings are described in a paper appearing in press May 26 (online May 28) in the American Journal of Pathology. This is the first peer-reviewed publication on convalescent plasma use in the U.S.

James M. Musser, M.D., Ph.D., chair of the Department of Pathology and Genomic Medicine at Houston Methodist, is the corresponding author on the study, titled "Treatment of COVID-19 patients with convalescent plasma." Eric Salazar, M.D., Ph.D., assistant professor of pathology and genomic medicine with the Houston Methodist Research Institute, is the principal investigator who led the project to treat critically ill COVID-19 patients with convalescent plasma.

"While physician scientists around the world scrambled to test new drugs and treatments against the COVID-19 virus, convalescent serum therapy emerged as potentially one of the most promising strategies," Musser said. "With no proven treatments or cures for COVID-19 patients, now was the time in our history to move ahead rapidly."

Patients were first treated under emergency use guidelines (eIND) from the U.S. Food and Drug Administration and then received approval April 3 from the FDA to open up the trial to more patients as an investigational new drug (IND). This extraordinarily rapid approval granted by the FDA opened up access to convalescent plasma treatment for COVID-19 patients.

The century-old therapeutic approach dates back to at least as early as 1918 to fight the Spanish Flu and more recently was used with some success during the 2003 SARS pandemic, the 2009 influenza H1N1 pandemic and the 2015 Ebola outbreak in Africa. Following a study early on in the COVID-19 pandemic, where a handful of critically ill patients in China showed improvement, an interdisciplinary team of Houston Methodist physician scientists and health care workers rapidly targeted the COVID-19 virus with convalescent serum therapy.

Additional findings during this trial revealed patient outcomes following plasma therapy were very similar to recently published results of patients treated on a compassionate-use basis with the antiviral drug remdesivir. The research team also concluded that any observed complications were consistent with findings reported for COVID-19 disease progression and did not result from the plasma transfusions. The study's overall findings were consistent with several other small case studies of convalescent plasma use for severe COVID-19 that have been recently reported.

Ultimately, although the convalescent plasma therapy administered on the front lines at Houston Methodist was implemented for emergency treatment, the study's authors recognize the important need for controlled clinical trials to determine its therapeutic efficacy. A randomized controlled trial is currently being considered at Houston Methodist where they would also look more closely at variables such as timing of the transfusion after the onset of symptoms, the number and volume of transfusions adjusted for patient biometrics, antibody levels in donor plasma and numerous other parameters needed to effectively evaluate how to optimize this therapy. This would help address some questions, including whether patients would have better outcomes if plasma transfusions were administered sooner after the onset of symptoms.

Not all plasma recipients transfused so far at Houston Methodist were part of this first trial. Since late March, when the first patients were infused with convalescent plasma, Houston Methodist has treated 74 critically ill COVID-19 patients, 50 of whom have been discharged from the hospital and are recovering. More than 150 recovered COVID-19-infected individuals donated their plasma, many of them continuing to do so frequently.

When it's time to schedule a vacation, most people will do it right away. But when it comes to booking a root canal, some people will procrastinate while others will put it at the top of their to-do list.

New research from the UBC Sauder School of Business may have figured out why. The study, published in the Journal of Consumer Psychology, reveals key insights into how excitement, anticipation and dread factor into people's decision-making.

"This stems from the phenomenon known as 'the sign effect'," says the study's author and UBC Sauder assistant professor, David Hardisty. "A person's desire to get positive things right away is stronger than their desire to put off negative ones. However, the timing of when a person wants to handle negative things is less obvious."

Hardisty and his team found that when people look toward positive events in the future, such as an upcoming vacation, they experience pleasure, but also impatience, which makes for a mixed emotional experience.

When it comes to upcoming losses, however, the emotion tends to be all bad -- even if that root canal is far away and life at this moment is good. So rather than postpone those negative events, many prefer to get them out of the way as soon as possible.

"When you're booking a vacation, you're vicariously enjoying the vacation, which is great, but you're also contrasting it with your current situation, which is bad. So you have that mix," says Hardisty. "And for losses, it's more of a unidimensional bad feeling. When you have a dentist's appointment coming up, you don't like thinking about the pain in the dental chair."

In one experiment, the researchers posted two advertisements on Facebook for retirement planning: one ad read "Looking forward to retirement benefits?", and the other read "Worried about retirement expenses?" The click-through rate for this second ad, focused on reducing worry, was 43 per cent higher.

In a second experiment, to create controlled positive and negative experiences, the researchers used jelly beans which come in flavours ranging from orange sherbet and watermelon to dirt and rotten egg. Participants were given the jelly beans to eat at different times, and rated how they felt about their upcoming gains -- the good-tasting jelly beans -- and losses (the bad ones).

Hardisty says some people procrastinate and put off negative events, but not as much as many would expect, because the negative anticipation is so unpleasant. The researchers' findings also counter earlier research that argued people put off positive events so they can savour the sweet anticipation.

In a separate but related study, Hardisty's team looked at how people feel about past events, both positive and negative, because it removes the effects of anticipation. In other words, how do people feel about that root canal they had a month ago, or that relaxing vacation?

They found that remembering bad events feels bad, and remembering good events feels good, effectively wiping out the sign effect.

The more events recede into the past, adds Hardisty, the more muted our emotional responses to them become.

While the research provides a fascinating look at human behaviour, Hardisty says it also has plenty of practical applications when it comes to everything from contemplating car loans to mapping out retirement plans.

"It's exciting to have an explanation for why people make choices the way we do," he says. "Hopefully it will lead to better interventions that can help people make better long-term choices about their finances and other life events."

Computer simulations conducted by astrophysicists at Tohoku University in Japan, have revealed a new theory for the origin of supermassive black holes. In this theory, the precursors of supermassive black holes grow by swallowing up not only interstellar gas, but also smaller stars as well. This helps to explain the large number of supermassive black holes observed today.

Almost every galaxy in the modern Universe has a supermassive black hole at its center. Their masses can sometimes reach up to 10 billion times the mass of the Sun. However, their origin is still one of the great mysteries of astronomy. A popular theory is the direct collapse model where primordial clouds of interstellar gas collapse under self-gravity to form supermassive stars which then evolve into supermassive black holes. But previous studies have shown that direct collapse only works with pristine gas consisting of only hydrogen and helium. Heavier elements such as carbon and oxygen change the gas dynamics, causing the collapsing gas to fragment into many smaller clouds which form small stars of their own, rather than a few supermassive stars. Direct collapse from pristine gas alone can't explain the large number of supermassive blackholes seen today.

Sunmyon Chon, a postdoctoral fellow at the Japan Society for the Promotion of Science and Tohoku University and his team used the National Astronomical Observatory of Japan's supercomputer "ATERUI II" to perform long-term 3D high-resolution simulations to test the possibility that supermassive stars could form even in heavy-element-enriched gas. Star formation in gas clouds including heavy elements has been difficult to simulate because of the computational cost of simulating the violent splitting of the gas, but advances in computing power, specifically the high calculation speed of "ATERUI II" commissioned in 2018, allowed the team to overcome this challenge. These new simulations make it possible to study the formation of stars from gas clouds in more detail.

Contrary to previous predictions, the research team found that supermassive stars can still form from heavy-element enriched gas clouds. As expected, the gas cloud breaks up violently and many smaller stars form. However, there is a strong gas flow towards the center of the cloud; the smaller stars are dragged by this flow and are swallowed-up by the massive stars in the center. The simulations resulted in the formation of a massive star 10,000 time more massive than the Sun. "This is the first time that we have shown the formation of such a large black hole precursor in clouds enriched in heavy-elements. We believe that the giant star thus formed will continue to grow and evolve into a giant black hole," says Chon.

This new model shows that not only primordial gas, but also gas containing heavy elements can form giant stars, which are the seeds of black holes. "Our new model is able to explain the origin of more black holes than the previous studies, and this result leads to a unified understanding of the origin of supermassive black holes," says Kazuyuki Omukai, a professor at Tohoku University.

Tiger snakes living in Perth's urban wetlands are accumulating toxic heavy metals in their livers, suggesting that their habitats - critical, local ecosystems - are contaminated and the species may be suffering as a result.

Lead researcher PhD Candidate Mr Damian Lettoof, from the Behavioural Ecology Lab in the School of Molecular and Life Sciences at Curtin University, said that not only were the snakes' livers shown to contain moderately high levels of heavy metals, but sediment samples taken from some of the wetlands sites were found to have amounts of arsenic, lead, mercury and selenium that exceed current government guidelines.

"Urban wetlands are almost always polluted, commonly from contaminated storm water, past or present dumping of waste, and spill events," Mr Lettoof said.

"Wetlands areas are usually situated at low points in the landscape, so unfortunately, a lot of urban run-off ends up in them. Generally speaking, the longer the wetland has been urbanised, the higher the levels of pollution.

"It's important to note that many heavy metals exist naturally in the wetlands sediment and surrounding rocks, in low concentrations, which may cause some heavy metals to leach in to the wetlands environment.

"However, the high concentrations of heavy metals we found in the snakes' livers and sediment samples suggest urbanisation and human-induced pollution are the cause, and consequently could be affecting local snake populations," Mr Lettoof said.

The study found the metal concentrations in the snake livers were collectively highest in Perth's most urbanised wetland: Herdsman Lake in the north western suburbs.

"Snakes tested from Herdsman Lake also had the highest concentration of the metal molybdenum ever reported in a terrestrial reptile, in the world," Mr Lettoof said.

"Continuous, chronic exposure to contaminants can have a range of impacts on the health and behaviour of animals. The contaminated populations could be suffering poorer health conditions, leading to shorter lifespans, higher predation, and ultimately, local extinction with cascading consequences such as reduced local biodiversity."

Collectively, Lake Joondalup had the lowest levels of metals. The researchers also analysed samples from Bibra Lake and Loch McNess in Yanchep National Park.

Tiger snakes are a top predator in the wetlands environment, and most likely have bioaccumulated the heavy metals through eating frogs, which are very sensitive to accumulating contaminants.

The Curtin University study was the first of its kind in Australia to show that snakes are a good bio-indicator of wetland contamination, and highlights the use of monitoring snake populations as an important indicator species of environmental health.

The team pre-published their report online in the Journal of Materials Chemistry A on 11 May 2020.

Imitating plants, algae and bacteria

Biosolar cells are an innovative concept for converting sunlight into electrical energy. They are manufactured using biological components from nature. At their core are so-called photosystems: large protein complexes that are responsible for energy conversion in plants, algae and cyanobacteria. Photosystem II, PSII for short, plays a central role in the process, because it can use water as an electron source for the generation of electricity.

Cooperation so far unsuccessful in the test tube

"However, as unique as PSII is, its efficiency is limited, because it can use merely a percentage of the sunlight," explains Professor Marc Nowaczyk, Head of the Molecular Mechanisms of Photosynthesis project group at RUB. When it comes to the so-called green gap in particular, PSII is almost inactive. "Cyanobacteria have solved the problem by forming special light-collecting proteins, i.e. phycobilisomes, which also make use of this light. This cooperation works in nature, but not yet in the test tube."

Super complexes use twice as many photons of the green gap

In collaboration with the research group of Professor Wolfgang Schuhmann at RUB and the Israeli research group of Professor Noam Adir, Nowaczyk's team has succeeded in producing a two-component bioelectrode. The main difficulty was the functional interaction of the multiprotein complexes, some of which were combined across species.

The researchers stabilised these super complexes using short-chain chemical crosslinkers that permanently fix the proteins at a very short distance from each other. In the next step, they inserted them into appropriate electrode structures. "We mastered this challenge by using customised, three-dimensional and transparent electrodes in combination with redox-active hydrogels," says Dr. Volker Hartmann, lead author of the study. This design enabled the researchers to use twice as many photons within the green gap, compared to a system without any light collection complexes.

Promising interim stage

The assembly of protein complexes in the test tube is considered a promising interim stage in the development of biological solar cells. The advantages of different species can thus be functionally combined in semi-artificial systems. In future, the researchers will be mainly focusing on optimising the production and life span of the biological components.

Funding

The research was funded by the Ruhr Explores Solvation Resolv Cluster of Excellence, the GRK 2341 Microbial Substrate Conversion Research School (Micon), which are financed by the German Research Foundation (DFG), and the German-Israeli research project Nano-engineered opto-bioelectronics with biomaterials and bio-inspired assemblies under the auspices of the DFG and the Israel Science Foundation.

Dating cave art is a key issue for understanding human cognitive development. Knowing whether the ability for abstraction and conveying reality involved in artistic development is unique to Homo sapiens or if it was shared with other species, or simply knowing at what moment these abilities developed, is vital in order to understand the complexity of human evolution.

Currently in Spain, for the most part, when trying to find out the age of artistic expressions in caves, dating is done with U-series dating, using the two elements uranium and thorium in the underlying and overlapping layers of calcite in the paint itself.

However, the timeline this system proposes seems to provide evidence for erroneous ages and an inverse relationship between the concentration of uranium and the apparent ages. In order to test the reliability of this dating method, Prehistory Professor at the University of Córdoba, José Luis Sanchidrián Torti and associate researcher in Prehistory at UCO María Ángeles Medina Alcaide, who do not doubt the cognitive abilities of the Neanderthals but rather adhere to scientific rigor, performed a study in which they analyzed the reliability of Uranium-thorium dating and refute Neanderthals being the creators of the Paleolithic art in Spanish caves via the Nerja Cave. The key, according to the Cordoba team, seems to be in the mobility of uranium, which would have assigned older (and inaccurate) ages to the cave art in some Spanish caves, ascribing the art to Homo neanderthalensis.

The research team analyzed several samples of calcite related to the chronometric test of a set of rocks in the Nerja Cave, obtaining proof of the complexity of the dating on calcite for the study of the chronology of cave art. In this way, they directly question the generally accepted conclusions to date about the artistic manifestations in several caves being the work of Neanderthals, which had been determined based solely on the Uranium-thorium dating method.

In order to reconstruct the timeline of the history of cave art, Sanchidrián and Medina's research proposes an action protocol for dating Paleolithic art samples that uses data from three measuring systems: Uranium-thorium testing, Carbon 14 (C14) testing and a second mineralogical study of the sample before dating.

It is essential to study in more detail the evolution of these artistic manifestations in order to establish a rigorous and reliable chronological framework that allows us to understand and comprehend human artistic development.

A new study from researchers at The University of Texas at Austin has found that some antivirals are useful for more than helping sick people get better -- they also can prevent thousands of deaths and hundreds of thousands of virus cases if used in the early stages of infection.

The study, published today in the journal Nature Communications, focused on influenza and has implications for the coronavirus that causes COVID-19. By modeling the impact of a pair of leading flu drugs, the team found significant differences in effects between oseltamivir, an older antiviral treatment for flu that patients know by the name Tamiflu, and a newer one, baloxavir, which is sold under the brand name Xofluza.

The researchers found that the newer treatment -- by effectively and rapidly stopping virus replication -- dramatically reduced the length of time that an infected person is contagious and, therefore, better limited the spread of flu.

"We found that treating even 10% of infected patients with baloxavir shortly after the onset of their symptoms can indirectly prevent millions of infections and save thousands of lives during a typical influenza season," said Robert Krug, a professor emeritus of molecular biosciences, writing for a blog that accompanied the paper.

Early basic research discoveries by Krug informed the development of baloxavir.

Krug and a team of epidemiological modelers headed by Lauren Ancel Meyers, a professor of integrative biology, concluded from the study that having a similarly effective antiviral treatment for the coronavirus would help to prevent thousands of infections and deaths. Creating such an antiviral would take time and new strategies in public health planning, but the benefits for patients, communities and health care settings could be profound.

"Imagine a drug that quashes viral load within a day and thus radically shortens the contagious period," said Meyers, who models the spread of viruses including the virus that causes COVID-19. "Basically, we could isolate COVID-19 cases pharmaceutically rather than physically and disrupt chains of transmission."

To date, most COVID-19 drug research efforts have prioritized existing antivirals that can be deployed quickly to treat the most seriously ill patients coping with life-threatening symptoms. The scientists acknowledge it would represent a shift to develop a new antiviral for the coronavirus, to be used early in an infection with the aim of curtailing viral replication, just as baloxavir does for flu.

"It may seem counterintuitive to focus on treatments, not for the critically ill patient in need of a life-saving intervention, but rather for the seemingly healthy patient shortly after a COVID-19 positive test," Krug said. "Nonetheless, our analysis shows that the right early-stage antiviral treatment can block transmission to others and, in the long run, may well save more lives."

Postdoctoral researcher Zhanwei Du carried out many of the modeling studies. UT graduate student Ciara Nugent and Alison P. Galvani of the Yale School of Public Health co-authored the paper, "Modeling mitigation of influenza epidemics by baloxavir." The team also wrote a companion blog post about the implications for COVID-19.

Cells are a little easier to understand, thanks to improved technology developed by a team of researchers based in China. Using a method called Raman-Activated Cell Ejection and Sequencing (RACE-Seq), the scientists were able to improve the success of identifying and sequencing individual cells from our environments to understand the cells' functions.

They published their results recently in Analytical Chemistry.

"RACE-Seq is a useful technology to identify, isolate and sequence single-cells with particular function from environment," said SU Xiaolu, paper author and a researcher with the Single-Cell Center in Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS). "However, the success rate and quality of RACE-Seq has been quite low for environmental samples."

Single-cell Raman sorting and sequencing tools such as RACE-Seq help researchers understand the mechanistic links between the function and genetic components of individual cells in nature. For genetically varied environments, such as soil found in the environment, RACE-Seq allows the cells to be sorted based on their function roles - without damaging them - and have their genome sequenced to establish those mechanic links between genetics and function.

During RACE-Seq, cells are loaded onto a microchip surface and air-dried immediately before being irradiated with a laser. Cells identified with the function being sorted for are identified and ejected into a receiving well on another chip. The cells are then broken apart and their genetic material processed to determine the underlying mechanical link to the particular function of interest.

Previously, this method can produce about 20% coverage of genome for individual E. coli cells. Now, the researchers have improved the method so the coverage reaches around 50%.

SU and his team found that adjusting the laser's energy input helped protect the cells to have better output. They also found that changing the duration, temperature or other aspects of the other steps did not help improve the output.

To tackle this problem, the researchers added oil before amplifying the DNA of sorted cells. This simple yet elegant operation reduces such harmful effects of Raman irradiation and increases greatly the completeness of the genomes. Moreover, for soil microbiota, which are perhaps the most complex microbial communities in nature, this new protocol dramatically improves experimental success rate of RACE-Seq.

"Our findings provide a practical solution for enhancing RACE-Seq performance, and thus should make this technique more accessible to the many laboratories interested in single-cell sequencing around the globe," said XU Jian, director of the Single-Cell Center.

The researchers also noted that RACE-Seq is still unable to produce good-quality genomes at precisely one-cell resolution from environmental samples. They are introducing novel technologies that can achieve the ultimate goal of functionally sorting and sequencing every microbial cell from natural environments.