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Remoras are among the most successful marine hitchhikers, thanks to powerful suction discs that allow them to stay tightly fastened to the bodies of sharks, whales and other hosts despite incredible drag forces while traveling through the ocean. But how do these suckerfish sense the exact moment when they must "stick their landing" and board their speedy hosts in the first place?

A team of biologists at New Jersey Institute of Technology (NJIT), Friday Harbor Labs at University of Washington (FHL-UW) and The George Washington University (GWU) now offers an answer.

In findings published in the Journal of the Royal Society Open Science, researchers have detailed the discovery of a tactile-sensory system stowed within the suction disc of remora, believed to enable the fish to acutely sense contact pressure with host surfaces and gauge ocean forces in order to determine when to initiate their attachment, as well as adjust their hold on hosts while traversing long distances.

Specifically, the study describes the discovery of groupings of push-rod-like touch receptors, or mechanoreceptor complexes, embedded in the outer lip of the remora adhesive disc, which have been known to aid other organisms in responding to touch and shear forces.

Researchers say the finding marks the first time such touch-sensory complexes have been described in fishes, as the structure was previously only known in extant monotremes-- platypus and echidnas.

"One of the wildest things about this work was not only finding a mechanoreceptor complex not previously known to fishes, but that the only other organisms known to possess them are monotremes," said Brooke Flammang, NJIT professor of biological sciences and lead author of the study. "This is exciting because it shows how much we as integrative comparative biologists still have to learn about the sensory world of organisms."

"When I was in graduate school, conventional wisdom was that fishes did not have such mechanoreceptors," said Patricia Hernandez, one of the study's authors at The George Washington University. "The discovery that these fishes share convergent receptors with echidnas is really exciting and points us in the right direction for discovering similar convergence in other fishes."

While conducting various imaging studies to examine the head and disc of Echeneis naucrates, a common sharksucker remora, the team successfully identified the complexes: dome-like protrusions along the surface of the soft tissue lip surrounding the remora's adhesive disc. Each dome packs below it a column of cells with three vesicle chains containing sensory nerves that stretch from the disc's epidermal layer down to its dermal layer. In addition to sensing contact, these complexes are thought to respond to shear stress, which would provide feedback information to the remora if it was losing its grip and sliding backward on its host.

"When we first noticed these structures we were a little thrown off," said Karly Cohen, a Ph.D. biology student at FHL-UW and an author on the study. "We knew they had to be sensory because of the plethora of nerves, but they didn't look like lateral line structures, which are one of the main ways fishes sense their environment. We dove into the literature to try and find structures that fit the morphology of those we saw in the remora histology. Finally landing on the push-rod receptors known in echidnas was so exciting. ... It was validation of the morphology we were seeing and it took us into a realm of mechnosensation that we were not necessarily considering when thinking about how the remora stick."

Notably, in further examining seven other remora species, the team found that those species known to frequently piggyback on larger and faster hosts, like pelagic billfish, are equipped with nearly double the mechanoreceptor complexes of remora species that typically hitchhike on slower swimmers, such as reef fishes.

"On animals swimming very fast where the remora may be under increased drag conditions, the need to recognize loss of contact and make an instant correction is more crucial than on slower swimming hosts," noted Flammang.

Flammang and colleagues say that the touch-signaling complexes found in remoras suggest not only that fishes may be able to sense their environment in ways not previously realized, but that specialized mechanoreceptors may also be a much more common feature among basal vertebrates than was previously thought as well.

"The interesting aspect here is that push-rods are only otherwise known in platypus and echidnas," said Flammang. "Obviously, there is no close phylogenetic relationship between remoras and monotremes, so this likely means that there are a lot of mechanoreceptors in vertebrates that just haven't been found in a wide breadth of organisms. We hope this paper brings this structure to the attention of other researchers for comparative study on how their organisms sense the environment."

Cambridge, Massachusetts - In today's world, most workers are highly specialized, but this specialization can come at a cost - especially for those on the wrong team. New research by Harvard's Growth Lab uncovers the importance of teams and coworkers when it comes to one's productivity, earning potential, and stays of employment.

The research - recently published in the journal Science Advances - analyzed administrative data on the 9 million inhabitants of Sweden. By constructing networks of complementarity and substitutability among specific educational tracks, the research assessed the importance of the skills of coworkers. It found that to earn high wages and returns on education, workers must find coworkers who complement, but not substitute, them. The returns to having complementary coworkers are large: the impact is comparable to having a college degree.

The research offers a tool to assess the right and wrong coworkers in fields of expertise. The right coworkers are those with skills you lack, yet needed to complete a team. The wrong coworkers are those who replicate your skillset and ultimately lower your value to the employer. For example, those with a degree in Architecture are best complemented by workers with engineering, construction, or surveying degrees, and negatively impacted by those with landscape or interior design degrees.

"We tend to think of skills as being something personal that individuals can market to a company,' said Frank Neffke, Growth Lab Research Director. "However, this vision of skills is too simplistic. One person's skills connect to another person's skills, etc., and the better these connections, the more productive workers will be, and the more they will earn."

Complementarity also drives careers. The research shows that people tend to stay longer in organizations with many complementary workers and tend to leave those with many workers who substitute them. These results hold true for up to 20 years of one's career.

The research also supports several well-known facts, such as cities and large firms pay higher wages. Workers are more likely to find better fitting teams in cities, and large firms often allow workers to specialize.

Neffke adds that the benefits of working with complementary coworkers are not the same for all workers. Those with higher levels of education seem to benefit much more from working in complementary teams than workers with lower levels. Over the past 20 years, workers with college degrees or higher have been increasingly able to find better matching coworkers.

Scientists have transferred a collection of genes into plant-colonizing bacteria that let them draw nitrogen from the air and turn it into ammonia, a natural fertilizer.

The work could help farmers around the world use less man-made fertilizers to grow important food crops like wheat, corn, and soybeans.

The group of scientists, including two from Washington State University, published the study "Control of nitrogen fixation in bacteria that associate with cereals" late last month in Nature Microbiology.

"There's a growing interest in reducing the amount of fertilizer used in agriculture because it's expensive, has negative environmental impacts, and takes a lot of energy to make," said John Peters, Director of WSU's Institute of Biological Chemistry and a co-author on the paper. "There's a huge benefit to developing ways to increase the contributions of biological nitrogen fixation for crop production around the world."

How legumes get nitrogen

The team's research helps share a symbiotic benefit found in legume crops, which farmers have relied on for centuries to naturally enrich the soil.

Legume crops, such as chickpeas and lentils, require significantly less fertilizer than other crops, because they've developed a symbiotic relationship with bacteria that grow within their root tissues. These bacteria convert nitrogen gas to ammonia through a process called biological nitrogen fixation.

Bacteria take nitrogen from the air and convert it into ammonia for the plants, which use it for energy to grow. The plants in turn provide carbon and other nutrients to the microbes.

To work symbiotically, legumes and microbes have evolved to release signals that each can understand. The plants give off chemicals that signal to the bacteria when they need fixed nitrogen. The bacteria produce similar signals to let the plants know when they need carbon.

Fertilizer reduction

To develop a synthetic method for this symbiosis between other bacteria and crops, scientists worked to determine the groups of genes in bacteria that enable nitrogen fixing, then add those gene groups into other bacteria.

"This is just one step, although a large step, on the road to figuring out how to promote increasing contribution of biological nitrogen fixation for crop production," Peters said.

Peters and WSU are co-leads on the overall project with his colleague Philip Poole at the University of Oxford in the UK.

Reducing fertilizer requirements could have massive impacts on food availability, energy use and agriculture costs all over the world.

Fertilizers are too expensive for many farmers around the world. Without them, many nutritionally valuable foods won't grow in many areas due to nitrogen-poor soil.

"This project is aimed at increasing food production and helping feed the world," Peters said. "Transforming food production to work without nitrogen-based fertilizers could be a huge development in underdeveloped countries. Adding these microbes would be like pouring kombucha on roots."

Complex challenge

Peters' lab specializes in studying metabolic processes in bacteria, or how they create and use energy. His lab provided a blueprint for how nitrogen fixation works in different organisms. Then his co-authors, synthetic biologists at the Massachusetts Institute of Technology, can create the mechanisms that microbes and plants will need.

"This is such a complex and wide-spread challenge it really takes a large team with varied areas of expertise to solve," Peters said. "But if we succeed, the reward could be huge for the entire planet."

Robots are becoming an increasingly important part of human care, according to researchers based in Japan. To help improve the safety and efficacy of robotic care, the scientists have developed a control method that could help robots better replicate human movement when lifting and moving a patient. They published their results in IEEE/CAA Journal of Automatica Sinica.

"In recent years, shortage of caregivers has become a serious social problem as the result of a falling birth rate and an aging population," said Changan Jiang, paper author and assistant professor of mechanical engineering at Ritsumeikan University.

Nursing care robots are already in use in several care facilities, but come with limitations. For example, robots responsible for lifting a patient from a bed to a chair must be heavily supervised by a human care provider. The control method the robot uses to lift and hold a person must also contend with the issue of friction. The weight of a human could cause the robot's arms to stall out in mid-movement.

In Jiang's paper, the researchers report the development of a method to control the movement of a nursing care robot's arm to make a safe and comfortable posture without having to compensate for the friction between care-receivers and the robot's arms in a computer simulation.

"In a real-world application, the friction cannot be ignored, and it will affect the arms' performance of holding and the lifting-up motion," Jiang said. "In our research, instead of compensating the friction, we utilize static friction reasonably during holding and lifting up of an object. This is the most important idea of our research."

Static friction keeps an object at rest. For example, a truck climbing a steep ramp must have enough force to propel itself upwards, otherwise static friction between the truck and the road will grind the movement to a halt and keep the truck still. With nursing care robots, the researchers made the static friction work for them by applying it to a two-link object--the robot's equivalent of a human arm. By assuming the arm is working from a state of static friction, with the care-receiver's body acting as the thing that keeps the arms from moving, the researchers programmed the arm to keep the body at rest. As such, the care receiver has a safe and comfortable experience, and the robot's arm doesn't need to work to compensate whatever friction is introduced.

Next, the researchers plan to add a third link to the control method, which will represent a torso.

"We plan to extend the two-link object to a three-link one, which is more similar to a human's body and to design a new control method to realize a safe and comfortable holding and lifting-up motion," Jiang said.

Satoshi Ueno, also with the Department of Mechanical Engineering at Ritsumeiken University, co-authored the paper.

During the past decade, our human evolutionary tree has turned into something more resembling an unwieldy bush. Scientists have discovered swapped segments of DNA that we shared from mating between two other hominids, Neanderthals and Denisovans, which were first sequenced in 2010 and 2014, respectively.

How much of our hominid cousins remains in each of us today, and whether or not the presence of ancient hominid DNA has conferred any adaptation advantages or disadvantages has been a prime area of exploration.

Scientists have shown that single hominid genes can convey advantages, including a famous case of high-altitude adaption, which was the result of DNA swapping, otherwise known as genomic introgression, of a Denisovan for the gene EPAS1. That discovery may help explain why Tibetans are uniquely adapted to high-altitude living.

But since most diseases are likely are result of multiple genes and often exhibit complex traits, unpacking ancient hominid contributions to our genomes has been a difficult task.

Now, in a new study published in the advanced online edition of Molecular Biology and Evolution, scientists Alexandre Gouy and Laurent Excoffier have developed new computational tools to better analyze human genome datasets, and found more evidence of a legacy of ancient hominid adaptation, particularly to help fight off infectious diseases like malaria.

"Our results confirm that archaic introgression is widespread in immunity-related genes and that pathogens represent a strong selective pressure which could be one of the major causes of adaptive evolution in humans," said the authors. "Overall, our results suggest that archaic introgression has affected human metabolism and response to different types of pathogens (bacteria, virus and protists), which have been critically determinant during human adaptive history," said Excoffier.

In this study, the duo analyzed the latest archaic introgression maps that have been recently made available for 35 Melanesian individuals as well as samples from the 1000 Genomes project.

"Our results show not only that introgression is found at many genes involved in the same functions, but also that some of these interacting genes carrying archaic DNA have been co-selected," said Gouy.

Rather than analyze individual genes, they set about focusing on methods to detect patterns of introgression based on biological pathway analysis and data sets of connected genes and subnetworks.

They were able to identify highly introgressed subnetworks among three primary biological pathway databases (KEGG, NCI and Reactome), and among each of the three populations they looked at, including East Asians, Europeans and Papua New Guineans.

One of the more striking areas of evidence of possible resistance to malaria among the Papua New Guineans.

"One of the most striking areas of evidence of adaptive introgression is a possible resistance to malaria among Papua New Guineans," said Excoffier.

Also, beyond infectious disease, they also found evidence of introgression in genes related to porphyrins that are involved in energy metabolism (respiratory chain) and iron and oxygen binding in red blood cells (hemoglobin) and muscles (myoglobin), as well as in olfactory receptors showing signals of Neandertal introgression among modern European populations.

One of the more strongly controversial areas is the development of modern human behavior and cognition. Though the authors caution the work is still very preliminary, they did find evidence of introgression among gene networks involved in such functions.

"These results suggest that archaic introgression might have also affected behavioral/neuronal traits, even though it is difficult to link these phenotypes to a precise selective pressure."

Their results build on other studies that have identified Neanderthal variants at two SLC loci (SLC6A11, SLC6A13) that have previously been associated with behavioral traits (depression, mood disorders, smoking behavior) and some gene variants that have been shown to be preferentially expressed in the brain.

"In Papuans, we also found genes showing a significant excess of introgression that have been respectively associated to autism susceptibility and attention deficit/hyperactivity disorder, e.g. SLC9A9," said Gouy. They also reported on other genes from the same family that have a brain-biased expression and show an excess of introgressed segments in East Asians and Europeans, including SLC6A1 (a GABA transporter), SLC6A5 (a neurotransmitter transporter) and SLC28A1, as well as in Papua New Guineans, with SLC4A10 (controlling intracellular pH of neurons and brain extracellular fluid).

Further explorations of these areas of influence will be needed to tease out their contributions to human health and disease.

Even though the overall amount of Neandertal and Denisovan introgression is quite low in modern humans (typically 1-3%), their evidence continues to build the scientific case that the hominid DNA that remains has helped shaped modern human adaptation. It also suggests that these hominid windows into the past have a strong impact and continue to exert their influence on the present fitness of modern humans.

Researchers at Princeton University have successfully recreated a key process involved in cell division in a test tube, uncovering the vital role played by a protein that is elevated in over 25% of all cancers. The researchers' findings, described in a pair of papers published in the journals eLife and Nature Communications, are a key step toward recreating the entire cell division machinery and could lead to new therapies aimed at preventing the growth of cancer cells.

When cells divide, a spindle-like structure composed of thousands of filaments called microtubules attaches to chromosomes and pulls equal numbers of them into each newly forming cell. Each microtubule is assembled from individual tubulin molecules and, because errors in chromosome segregation can lead to cancer, it is vital that they assemble into microtubules at the right time and place to form a functional spindle apparatus. Branching microtubule nucleation, in which a new microtubule forms from the side of an existing one, is crucial to this process because it allows the cell to form large numbers of microtubules that all point toward chromosomes, enabling their capture by the spindle.

Branching microtubule nucleation depends on several pieces of molecular machinery. One piece, called the gamma-tubulin ring complex (γ-TuRC), initiates the assembly of tubulin molecules into microtubules, while another, known as the augmin complex, recruits γ-TuRC to the side of existing microtubules. A protein called TPX2, whose levels are elevated in over 25% of all cancers, is also involved in branching microtubule nucleation. Elevated TPX2 levels lead to both aberrant microtubule assembly in cells and poor outcomes in cancer patients. But how TPX2 works with augmin and γ-TuRC to mediate branching microtubule nucleation and spindle assembly has remained unknown.

"To better understand the mechanism of branching microtubule nucleation, we set out to reconstitute the process outside of the cell using purified proteins," said Sabine Petry, assistant professor of molecular biology at Princeton.

In the eLife study, graduate students Raymundo Alfaro-Aco and Akanksha Thawani describe how they recreated branching microtubule nucleation in a test tube. One key finding from the study is that, like augmin, TPX2 can bind to microtubules and recruit γ-TuRC to initiate branching microtubule nucleation. Another surprising finding was that TPX2 also helps recruit augmin to microtubules, further enhancing the recruitment of γ-TuRC.

"Branching microtubule nucleation therefore occurs most efficiently when augmin, TPX2, and γ-TuRC are all present," Alfaro-Aco said. "Surprisingly, TPX2 lies at the very heart of controlling this reaction, despite being only a single protein amongst the large multi-subunit complexes augmin and γ-TuRC."

In the Nature Communications paper, Petry and her former graduate student Matthew King further reveal that TPX2 behaves like a liquid in promoting branching microtubule nucleation. Specifically, TPX2 forms a liquid layer on the surface of existing microtubules that beads up into tubulin-containing droplets, much like morning dew on spider webs. The researchers found that TPX2 and tubulin can condense together to form liquid-like droplets through a phase-separation mechanism identical to the one that causes oil droplets to form in water. New microtubules can form from these TPX2-tubulin droplets and, because the droplets condense on the surface of existing microtubules, this results in the formation of branched microtubule structures.

"The study suggests that the co-condensation of TPX2 and tubulin creates a local reservoir of tubulin on a pre-existing microtubule that may be necessary to efficiently promote branching microtubule nucleation," King said.

Together, both studies reveal that TPX2, somewhat overlooked before, is the lynchpin of branching microtubule nucleation. It travels to microtubules first to assemble all of the other components that ultimately give rise to a branching microtubule, and it does this while behaving like a liquid. Petry and colleagues think that cellular signals may regulate TPX2 condensation to ensure that it only occurs when a cell is dividing and needs to form a spindle. "Our findings on the behavior of TPX2 may guide future therapeutic efforts aimed at modulating cell division," Petry said. "In addition, our reconstitution of branching microtubule nucleation is an important step toward reconstituting the entire spindle apparatus, as well as other cellular structures that depend on this microtubule assembly pathway."

Employing advanced technologies that allow whole brain imaging at single-cell resolution, researchers at University of California San Diego School of Medicine report that in an alcohol-dependent mouse model, the rodent brain's functional architecture is substantially remodeled. But when deprived of alcohol, the mice displayed increased coordinated brain activity and reduced modularity compared to nondrinker or casual drinker mice.

The findings, published in the January 14, 2020 online issue of PNAS, also identified several previously unsuspected regions of the brain relevant to alcohol consumption, providing new research targets for better understanding and treatment of alcohol dependence in humans.

"The neuroscience of addiction has made tremendous progress, but the focus has always been on a limited number of brain circuits and neurotransmitters, primarily dopaminergic neurons, the amygdala and the prefrontal cortex," said senior author Olivier George, PhD, associate professor in the Department of Psychiatry at UC San Diego School of Medicine.

"Research groups have been fighting for years about whether 'their' brain circuit is the key to addiction. Our results confirm these regions are important, but the fact that we see such a massive remodeling of the functional brain architecture was a real shock. It's like studying the solar system and then discovering that there is an entire universe behind it. It shows that if you really want to understand the neurobiological mechanisms leading to addiction, you can't just look at a handful of brain regions, you need to look at the entire brain, you need to take a step back and consider the whole organ."

George said the findings further undermine the idea that addiction is simply a psychological condition or consequence of lifestyle. "You would be surprised at how prevalent this view remains," he said. "The brain-wide remodeling of the functional architecture observed here is not 'normal.' It is not observed in a naïve animal. It is not observed in an animal that drinks recreationally. It is only observed in animals with a history of alcohol dependence and it is massive. Such a decrease in brain modularity has been observed in numerous brain disorders, including Alzheimer's disease, traumatic brain injury and seizure disorders."

Brain modularity is the theory that there are functionally specialized regions in the brain responsible for different, specific cognitive processes. For example, the frontal lobes of the human brain are involved in executive functions, such as reasoning and planning, while the fusiform face area located in the lower rear of the brain is involved in recognizing faces.

Reduced modularity, said George, likely interferes with "normal neuronal activity and information processing and contributes to cognitive impairment, emotional distress and intense craving observed in mice during abstinence from alcohol."

Due to the format of the testing, George said it was not clear if the reduced modularity was permanent. "So far, we only know that it lasts at least one week into abstinence. We have not tested longer durations of abstinence, but it's one of our goals."

George and colleagues used multiple new and emerging imaging technologies to create their whole-brain atlas of mouse brains, capable of being viewed at the level of single cells. The result was a first, they said, providing unprecedented data and insights.

"This new approach allows us to explore an entirely new universe. It can answer so many questions. What I am most interested in now is figuring out how early these brain changes start and how long do they last for. This would be critical to understanding when the switch to addiction happens and when does your brain come back to normal, if it ever does. We are also very interested in comparing the brain network of alcohol dependence with other drugs, such as cocaine, nicotine and methamphetamines."

The imaging approach cannot yet be used with human brains, which are far larger and more complex. "I don't think that it is possible to do it in humans now, the technology is just not there," said George. "But when I started doing this research 15 years ago, this technique didn't exist at all and I never ever imagined it would be possible, so who knows what the future will bring."

The cat parasite Toxoplasma gondii is known to cause infected rodents to lose their fear of feline predators, which makes the mice easier to catch. Predators then spread the parasites through their feces. But this so-called fatal feline attraction theory is flawed, suggests a study publishing January 14 in the journal Cell Reports. Rather than exhibiting a loss of feline-specific fear, infected rodents actually show a decrease in general anxiety and reduced aversion to a wide range of threats.

"For 20 years, T. gondii has served as a textbook example for a parasitic adaptive manipulation, mainly because of the specificity of this manipulation," says co-senior study author Ivan Rodriguez of the University of Geneva. "We now show that the behavioral alteration does not only affect fear of feline predators but that major changes occur in the brain of infected mice, affecting various behaviors and neural function in general."

T. gondii is a single-celled parasite that infects most species of warm-blooded animals, including humans, and causes the disease toxoplasmosis. Toxoplasma can persist for long periods of time in the body, possibly even for a lifetime. More than 40 million people in the United States may carry the parasite.

While very few infected humans have symptoms, toxoplasmosis is considered to be a leading cause of death attributed to foodborne illness in the United States. Infection during pregnancy can result in fetal death, and toxoplasmosis is also a threat in individuals with compromised immune systems, such as HIV-infected individuals. With a worldwide prevalence of about 30% in the human population, latent toxoplasmosis is a risk factor for several mental illnesses, including schizophrenia, Parkinson's disease, and bipolar disorder, as well as traffic accidents and suicide attempts.

Past studies have also shown that T. gondii causes a phenomenon known as fatal feline attraction--a decrease in aversion to cat odors in infected rodents. After infected rodents are eaten by feline predators, the parasite is passed through cat feces to various hosts, facilitating parasite spreading.

"It was particularly intriguing for us to understand how the parasite achieves a specific alteration of the neural circuits involved in the fear responses toward feline predators, something that has never been elucidated," says co-senior study author Dominique Soldati-Favre of the University of Geneva. "Our initial idea was to investigate the molecular mechanisms behind this behavioral manipulation. But considering that many contradictory or inconsistent results have been reported regarding the effects of T. gondii infection on rodent behavior, we later decided to reappraise the dogma."

In the new study, the researchers found that T. gondii infection does not selectively reduce fear of feline predators. Mice infected with the parasite for five to 10 weeks spent more time in the open arms of an elevated plus maze and showed more exploratory behaviors in novel environments compared to uninfected mice. In addition, infected mice did not show the normal preference for interacting with a nonaggressive male mouse compared with objects such as a metallic cube and an apple.

While uninfected mice showed avoidant, defensive, and anxiety-related behavioral responses to a potential threat--the hand of an experimenter--infected mice quickly touched the hand and thoroughly interacted with it. "Taken together, these findings suggest that chronic T. gondii infection reduces anxiety and risk aversion while increasing curiosity and exploratory behavior," says co-first author Madlaina Boillat of the University of Geneva.

Another set of experiments showed that T. gondii infection reduces fear of various animals, including non-predators. Consistent with previous studies, infected mice, but not uninfected mice, were clearly attracted to bobcat urine. But infected mice also spent more time investigating guinea pig and fox odors compared with uninfected mice, showing no particular preference for bobcat odor. While uninfected mice froze in fear in the presence of an anesthetized rat, infected mice boldly walked over the rat. "These results contrast with the prevailing idea that the parasite's manipulation of host behavior specifically targets neural circuits responding to feline predators," says co-first author Pierre-Mehdi Hammoudi of the University of Geneva.

To further examine this question, the researchers used light-sheet microscopy to accurately map the brain-wide distribution, size, and number of cysts at unprecedented resolution in 3D. Analysis of the whole brains of mice 10 to 12 weeks after infection showed that the density of parasite-filled tissue cysts was especially high in the cerebral cortex--the outer tissue layer in the brain--especially brain regions involved in processing visual information. However, cyst localization was widespread, and cyst number and distribution varied widely across mice, suggesting a random infection and dissemination process.

Importantly, additional analyses showed that the severity of T. gondii-induced behavioral changes was associated with cyst load and neuroinflammation. "Taken together, the findings point toward behavioral manipulation mediated by neuronal inflammation rather than direct interference of the parasite itself with specific neuronal populations," Rodriguez says. "It is not a simple on/off system. In the future, the level of chronic infection should therefore always be taken into account when studying effects of T. gondii on its host."

Even though the behavioral effects induced by T. gondii infection are not specific, they are still adaptive for the parasite. Infected rodents are presumably easier to catch by various predators, facilitating parasite spreading. On the other hand, research on the protozoan parasite Eimeria vermiformis, which also reduces predator fear in infected mice, suggests that the behavioral effects of infection are not adaptive in all cases.

Moving forward, the researchers plan to examine in more detail how neuroinflammation can alter behavioral traits such as anxiety, sociability, or curiosity. In the meantime, they urge caution in translating the findings more broadly, noting that humans generally exhibit fewer symptoms than rodents following T. gondii infection. "We hope that people understand that they will not get the 'crazy cat lady syndrome' if they are infected with T. gondii," Soldati-Favre says. "Although it seems that subtle behavioral changes may occur in humans, the inflammation in the human brain might never reach the same level as laboratory infected mice."

The sex life of hermaphroditic animals is determined by one fundamental question: Who assumes the female role and produces the costly eggs? Hamlets avoid this dilemma by engaging in reciprocal egg trading. Scientists have now used microeconomic models to analyze the circumstances required for this complex system of trading to work. Their results have been published in The American Naturalist.

The hamlets that live in coral reefs in the Caribbean are hermaphrodites. One of their mating strategies is to pass eggs on to each other. Here, the role of the sperm donor is preferable because producing eggs requires more energy. If both animals adopt the two roles successively when mating with the same partner, neither is at a disadvantage - it's a fair deal.

Traders, providers, and cheaters

Other populations from the Serranidae family do not engage in trading of this kind. Instead, they pass their eggs on unconditionally when they encounter an individual of the same species who is available for mating.

Reciprocal egg trading is presumably not an original evolutionary strategy, as the exchange is reliant on complex reciprocal behavior. An interdisciplinary team of researchers has now investigated the factors that could be responsible for the evolution of egg trading in hamlets - but not in other Serranidae.

For this, the researchers developed a model that takes account of a third type of behavior that can undermine the success of the egg trading strategy: one of the two fish - the "cheater" - pretends to want to reciprocate by providing eggs of their own, but then withdraws from the trade after fertilizing their partner's eggs.

Biology and game theory

Professor Georg Noeldeke, an economist at the University of Basel, is an expert in game theory. "Game theory asks how decision behavior can best be adapted to situations that are primarily determined by the decision behavior of other individuals," he says. "In principle, it doesn't make much difference whether this is animal behavior or the behavior of humans."

In collaboration with the marine biologist Oscar Puebla and the behavioral ecologist Jorge Peña, the microeconomist Noeldeke therefore believed he could design a game-theoretic model of the mating behavior of hermaphrodites that explained both the emergence of egg trading and the prevalence of this strategy over other possibilities.

Four necessary conditions

The results reveal restrictive conditions that must be met in order for reciprocal trading to invade and be maintained in a population. First, eggs must be relatively costly to produce. Second, it must not be too difficult to find a partner. "It only makes sense to wait for someone with whom a fair trade is possible if there's a relatively high probability that I'll encounter someone like that in the first place," explains Noeldeke.

Third, it mustn't be too easy to find a partner either, as otherwise the possibility of cheating is too attractive. Last of all, it must be possible to identify cheaters prior to fertilization and hence avoid mating with them. This is the only way that the trading strategy is worth pursuing, says the researcher.

"This model has enabled us to demonstrate theoretically, for the first time, which factors hold the key to explaining the egg trading system," says Noeldeke, describing the significance of the findings. "We now hope that other biologists will gather the necessary data to test our theory, and we can't wait to see the results."

Lithium nitride is a well-known positive pre-lithiation additive that can be used to compensate for the irreversible lithium loss that occurs on the negative side during the first charge, thereby increasing the specific energy of the energy storage device. However, in the electrode manufacturing process, lithium nitride would react with the most commonly used solvent, such as N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), acetonitrile (ACN) and N,N-dimethylacetamide (DMAC). The side reactions make it difficult to manufacture the lithium nitride containing electrode in scale. In this work, it was found that N,N-dimethylformamide (DMF) can be used as a homogenizing solvent to prepare a stable lithium nitride-containing slurry and electrode. Then the problem is solved.

The electrode can realize pre-lithiation of the lithium ion supercapacitor negative electrode, greatly improve the specific energy of the device, and maintain excellent rate performance and cycle stability. The energy retention remains 90% after 10,000 cycles. This technology is expected to find application in other battery systems with low initial efficiency in anode (hard carbon, silicon, etc.)

This work was reported in Science Bulletin, entitled "DMF stabilized Li3N slurry for manufacturing self-prelithiatable lithium-ion capacitor" by Prof. Zhang Hongzhang and Li Xianfeng's group in Dalian Institute of Chemical Physics, Chinese Academy of Sciences. The researchers studied the common polar solvents and found that the presence of α-H is the main factor affecting the instability of the solvent on the surface of lithium nitride.

Those nice new clothes you got for Christmas or in the new year sales might just last longer, thanks to advice from scientists researching the impact washing machines have on clothes and the environment.

Academics from the University of Leeds and specialists from Procter & Gamble, makers of Ariel, Daz, Bold, Fairy and Lenor, have wrung out new insight into how laundering clothing affects fading, colour runs and microfibre release.

Every load of washing releases hundreds of thousands of microfibres - tiny strands that are flushed down the drain.
Many reach beaches and oceans where they can remain for many years and be swallowed by sea creatures.

In what is the first research into wash cycle duration that used both laboratory and real consumer testing, they found that reducing both washing cycle length and water temperature can significantly extend the life of garments and reduce the quantity of dye and microfibres shed into the environment.

Report lead author Lucy Cotton, from the University's School of Design, said: "We are increasingly familiar with the environmental threat posed by throwaway fast fashion, but we also know that consumers claim their clothes can lose their fit, softness and colour after fewer than five washes - this means it's more likely they will ditch them long before they are worn out.

"Using shorter, cooler washes is a simple way everyone can make their clothes last longer and keep them out of landfill."

Dr Cotton worked with Dr Adam Hayward and Dr Neil Lant from P&G's Newcastle Innovation Centre, as well as Leeds colleague Dr Richard Blackburn. Their findings are published today in the journal Dyes and Pigments.

Mimicking average household loads, they washed 12 dark and eight brightly-coloured t-shirts, together with white fabric squares to test colour-fastness.

Conventional domestic washing machines and Ariel pods of biological detergent were used, comparing 30 minute cycles at 25°C, and 85 minute cycles at 40°C (both with 1,600rpm spins) for 16 cycles each. The research was repeated and validated with authentic loads of dirty laundry provided by UK consumers.

A series of tests were carried out on the garments and fabric squares, and the washing machine waste water analysed. Chemical analysis distinguished individual dyes washed out of the clothing, and microfibres were collected and weighed.

The tests established:

There was significantly less colour loss in the t-shirts that were washed using the cooler, quicker cycle;

Quicker, cooler washes decreased dye transfer from coloured washing;

Significantly less microfibres were released into wastewater during the quicker, cooler wash.

The researchers found washing with a quicker, cooler cycle reduced the amount of microfibre release into the environment by up to 52%, and cut dye release by up to 74%.

Dr Blackburn, who heads the Sustainable Materials Research Group at Leeds, said: "Our findings can help tackle the issue of 'invisible' plastics in the environment.

"Synthetic microfibres are released every time textiles are washed and account for more than a third of all plastic reaching the ocean. But microfibres from cotton and other natural sources are found in even greater numbers in the sea, and we're worried about their impact too.

"Our research shows that consumers can actively reduce the number of microfibres released from their own clothing simply by washing in quicker, cooler cycles."

What is more, washing clothes at 20°C rather than 40°C saves approximately 66% of the energy used per load - according to the Energy Saving Trust, providing even more reason to use quicker, cooler cycles to reduce energy use and CO2 emissions.

Dr Lant, a Procter & Gamble Research Fellow, added: "Advances in detergent technology, especially in sustainable ingredients such as enzymes, are allowing consumers to get excellent cleaning results in colder and quicker washes.

"It's well known that these cycles reduce our energy bills and carbon footprint, but our partnership with the University of Leeds is helping us understand how they also slow down the ageing of clothes - keeping us looking smart, saving us money replacing garments and helping the environment. It's a real win win win."

Further information:

"Improved garment longevity and reduced microfibre release are important sustainability benefits of laundering in colder and quicker washing machine cycles" is published on 14 January 2019 in Dyes and Pigments.

The recent progress on two-dimensional (2D) van der Waals ferroelectrics may revolutionize the applications of ferroelectric (FE) materials in nanoelectronics. Their atomic-thickness renders high-density integration; their clean van der Waals interfaces allow for lattice mismatch, facilitating the epitaxial growth on various substrates including silicon; meanwhile many 2D materials are also high-mobility low-bandgap semiconductors. Predictions of intrinsic FE in several 2D materials have been experimentally confirmed, such as IV-VI group compound, In2Se3, van der Waals bilayer, Bi2O2Se, etc..

2D multiferroics with magnetoelectric (ME) couplings have also been explored, which are highly desirable for realizing efficient "magnetic reading + electric writing". Multiferroic materials which are both FE and magnetic are rare in nature due to the mutual exclusive origins of the two orders (empty d shell for conventional FE order and partially filled d shell for magnetic order). Meanwhile, for traditional multiferroics, the ME coupling is weak in type-I multiferroics with ferroelectricity and magnetism arising respectively from different mechanisms, while for type-II multiferroics where ferroelectricity is induced by magnetic ordering their spin-driven FE polarizations (mostly

In a new article published in the Beijing-based National Science Review, scientists at Huazhong University of Science and Technology and at the Nanjing University, China present a first-principles predictions of 2D multiferroics with robust and diversified magnetoelectric couplings: thin-layer CuCrX2 (X=S or Se).

"Theoretically, the mutual exclusion between ferroelectricity and magnetism or between high Curie temperature and strong magnetoelectricity in traditional multiferroics can be avoided here." they state in an article titled "Room-Temperature Multiferroicity and Diversified Magnetoelectric Couplings in Two-Dimensional Materials." "The vertical ferroelectricity is neither induced by empty d-shell nor spin-driven, giving rise to an alternative possibility of resolving those intrinsic exclusions and contradictions."

"Tri-layer Cu-intercalated CrX2, denoted as Cu2(CrX2)3, is still completely FM for X=Se while Cu2(CrS2)3 possesses much more complex spin configurations. Although the magnetic coupling is FM in-plane for Cu2(CrS2)3, we still need to check various possible configurations of interlayer coupling as listed in Table. S3. The FM state is higher in energy compared with three ferrimagnetic states, and the ground state turns out to be the configuration in Fig. 4(a), with a total magnetization of 2.62 μB/f.u.. When the polarization is aligned downwards, the middle layer is FM coupled with the top layer while AFM coupled with the down layer; as the polarization is reversed, according to the symmetry, the middle layer should be AFM coupled with the top layer and FM coupled with the down layer in the ground state. The energy will be lowered by 16.4 meV with the magnetization reversal of the middle layer, which should take place spontaneously considering the small barrier of spin switching equivalent to the spin anisotropy energy (

"Their ferromagnetism can be stabilized due to enhanced carrier density and orbital shifting by the vertical polarization, and the Curie temperature of both ferromagnetism and ferroelectricity can be above room-temperature. Layers with different thickness may exhibit diversified types of magnetoelectrics for efficient magnetic reading + electrical writing due to the gradient of interlayer coupling parameter, where a considerable net magnetization can be reversed upon FE switching." they add. "Our prediction does not only exploit new types of multiferroic couplings in 2D, but also propose a way of constructing robust multiferroics for practical applications, which may stimulate experimental efforts concerning the recent synthesis of previously predicted intrinsic 2D ferroelectrics."

In school buildings with indoor air quality related problems, such as moisture damage, temperature problems or poor ventilation, pupils experience slightly more symptoms than in buildings in which conditions are stated to be good based on expert evaluation.

However, the association between indoor air quality of the school building and the pupils' symptoms was so weak that it is not possible to reliably assess the quality of the indoor air based on the amount of reported symptoms. This was found in a recent study, by the Finnish Institute for Health and Welfare and the University of Helsinki, which was published in the scientific journal Environmental Health.

The researchers found that inadequate indoor air quality was connected to the pupils' respiratory and general symptoms, such as colds, coughs and headaches. Some link to lower airway or skin symptoms was also found, but not to eye symptoms.

It is worth maintaining and investigating buildings

Earlier research also suggests that symptoms are not a good marker of the indoor air quality of a building.

"We need more research on how much indoor air impurities explain the differences in symptoms between schools, in comparison to other factors that influence symptoms. To date, these other factors have been remarkably little researched," said Professor Juha Pekkanen.

Besides indoor air, other factors that influence symptoms include the age of the person, their health and stress levels, including how well they are doing and feeling at work and school, and beliefs and concerns about the risks of poor indoor air. The fact that many issues influence people's symptoms in indoor environments needs to be considered when interpreting the results of indoor air questionnaires.

"Questionnaires aimed at building users provide valuable additional information for the management of indoor air quality problems. However, the decisions on renovations should be based primarily on data obtained by investigating the building," said Chief Physician Jussi Lampi.

The study included 129 lower and upper primary school buildings in the Helsinki area. The building conditions were assessed based on the City of Helsinki's evaluations. The Finnish Institute of Health and Welfare's indoor air questionnaire was used to gather data about pupils' symptoms. More than 12,000 pupils responded to the questionnaire. The response rate was 60%.

Superfluids were first discovered as a special quantum state of liquid helium, later dubbed as "Superfluid helium" once chilled past -269 degree celsius, starts to manifest properties that do not occur in other fluids. Penetration through a solid with nano-pores is one of the three fascinating macroscopic phenomena that are well known in superfluids such as liquid helium. It is zero viscosity that endows the liquid helium superfluid with zero flow resistance or frictionless flow, leading to the amazing property. Nevertheless, the superfluid penetration effect emerges only in the so-called quantum states or quantum fluids at extremely low temperatures of almost zero Kelvin. In contrast, conventional liquid droplets such as water and oils can diffuse into a solid with macro-pores at room temperature as a result of the capillary effect, but their surface tension makes them unable to penetrate through the porous material.

Room-temperature liquid metals, such as liquid gallium and its eutectic alloys, have attracted a great deal of attention in many research fields due to their unique properties. In recent years, liquid metal has attracted the attention of scientists with its low-temperature liquid state, high surface tension, electricity, and heat conductivity characteristics, and provided new ideas for the development of flexible electronic devices and software robots.

One particular noteworthy property is its ability to change its surface tension through the application of a voltage in a solution coupled with the fact that the surface tension of liquid gallium and its alloys is quite high, which makes it an ideal platform to study surface tension effects. As an important member of the liquid metal family, the gallium indium tin alloy droplet itself has great surface tension and exhibits the shape of the sphere in air or solution of NaOH. However, if a positive voltage is applied to the droplet while immersed in NaOH solution, the droplets rapidly form a surface oxide under the action of the electrochemical reaction, so that the surface tension is reduced to almost zero. Because of this, the droplets will spread along the surface.

Inspired by the near-zero surface tension, a team led by Professor Xiaolin Wang at the Institute of Superconducting and Electronic Materials, Australian Research Council Centre of Excellence in Future Low Energy Electronics Technologies, University of Wollongong, Australia, has discovered a voltage induced "superfluid" like penetration effect in Galium based liquid metals at room temperature for the first time. Prof Wang's team demonstrated the liquid metal penetration effect in various porous materials such as tissue paper, thick and fine sponges, fabrics, and meshes. The penetration effect mimics one of the three well-known superfluid properties of liquid helium superfluid that only occur at near-zero Kelvin. The underlying mechanism is that the high surface tension of liquid metal can be significantly reduced to near-zero due to the voltage induced oxidation of the liquid metal surface in a solution. It is the extremely low surface tension and gravity that cause the liquid metal to superwet the solid surface, leading to the penetration phenomena.

The team has demonstrated two possible applications such as healing and the cutting off of electrical wiring using liquid metal in a sealed environment.

The related results are published in the National Science Review (NSR) with the title of "Voltage Induced Penetration Effect in Liquid Metals at Room Temperature".

The penetration phenomena is another important finding for the team following the discovery of other liquid metal phenomena such as non-contact patterning, simultaneous deformation, and solidification of supercooled liquid metal, and heart beating. These findings offer new opportunities for novel microfluidic applications and could promote further exploration for more exotic fluidic states of liquid metals.

Engineered ingestible molecular traps created from mesoporous silica particles (MSPs) introduced to the gut can have an effect on food efficiency and metabolic risk factors. The results from studies on mice, published in Nanomedicine, demonstrate the potential to reduce the energy uptake into the body and could lead to new treatments for obesity and diabetes.

So far there are no effective treatments for obesity that hinder weight gain or promote weight loss without problematic side effects. Many of the current medications use small pharmacological agents that can affect the body negatively in multiple ways.

"We chose an innovative alternative approach. Mesoporous silica particles (MSP) are a type of ingestible synthetic silica particles that can be produced with a large surface area and a range of pore sizes", says professor Tore Bengtsson at the Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University and the one heading the research team behind the study.

The team hypothesised that the particles could be used as "molecular sieves" in the intestine to trap and block digestive enzymes that break down food and thus reduce the energy uptake into the body (measured as food efficiency).

In the study reported in Nanomedicine, mice were fed high fat, high calorific diets, to induce weight gain, mixed with specially engineered MSPs. The results showed that MSPs reduced food efficiency by 33 percent leading to a lower weight gain, and a positive effect on the metabolic profile, as well as significant lower levels of adipose tissue formation and leptin, together with lower levels of circulating insulin.

"The data presented in this study suggest that tailored MSPs could be used to treat obesity and diabetes in humans, especially when taking into account their excellent safety profiles. Since we completed this work, clinical trials have been devised and are now underway," says professor Tore Bengtsson.