Culture

Amyloids, abnormal fibrillar aggregates of proteins, are associated with various disorders such as Alzheimer's disease. Therefore, an in-depth understanding of the mechanisms of amyloid formation is critical for developing clinical strategies and drugs against these diseases. However, accumulating evidence suggests that amyloid formation processes and the consequent morphology of fibrils can be affected by various environmental factors. This is an obstacle for the integrative understanding of the mechanisms underlying amyloid formations. As gravity causes convectional perturbations in the microenvironments surrounding amyloid fibrils in solution, it may unavoidably affect the processes of molecular assembling. To test this possibility, the collaborative research team of Japan, involving Exploratory Research Center on Life and Living Systems (ExCELLS), Institute for Molecular Science (IMS), and National Institute for Physiological Sciences (NIPS) of National Institutes of Natural Sciences, Nagoya City University (NCU), and Japan Aerospace Exploration Agency (JAXA), characterized amyloid formation under microgravity conditions using the International Space Station (ISS). They compared the fibril formation of Alzheimer's disease-related amyloid β (Aβ) proteins on the ISS with that on the Earth and found that the process of Aβ fibrillization significantly slowed down in the microgravity environment. Furthermore, distinct morphologies of Aβ fibrils were formed on the ISS. Therefore, the project highlights the utility of the ISS as an ideal experimental environment for investigating the mechanisms of amyloid formation without uncontrollable perturbations caused by gravity, thereby providing fundamental insights into the pathological amyloid formation.

In an unprecedented first, scientists at Seattle Children's Research Institute have developed a genetically attenuated parasite (GAP) that arrests late in the liver stage of human malaria. Their findings published in JCI Insight pave the way for a novel, next generation vaccine against Plasmodium falciparum, the parasite that causes the deadliest form of malaria in humans.

According to Dr. Debashree Goswami, a fellow in the Kappe Lab at the research institute's Center for Global Infectious Disease Research and lead author of the paper, a vaccine candidate based on their findings has the potential to offer protection to those living in regions where the transmission of malaria is widespread throughout the population.

More effective vaccines are needed to successfully eradicate malaria, a disease that results in more than 228 million cases and 400,000 deaths annually. A vaccine that targets the clinically silent phase of parasite infection in the liver and prevents blood stage infection, would not only decrease mortality in especially vulnerable groups like children under age 5, but also block the cycle of transmission.

"Even the most promising experimental vaccine candidates, which can offer up to 52% protection in areas with intense malaria transmission, need to be improved upon to eliminate malaria," Goswami said. "We must strive for 100% protection."

Pioneer in GAP vaccines for malaria

The Kappe Lab is pioneering the development of GAP vaccines for malaria. To engineer a GAP, scientists select genes to delete from the parasite's DNA. This approach allows the GAPs to stop in the liver without ever reaching the dangerous blood stage of infection.

The arrest of these GAPs in the liver exposes them to the immune system and engenders a powerful and effective immune response that can block a new malaria infection from the moment a person receives an infectious mosquito bite.

A first-generation GAP vaccine, called GAP3KO, has successfully completed the first safety phase of clinical trials and is in continuing clinical development.

Late liver stage-arresting GAPs aim to be the gold standard in vaccine development

To improve upon first generation GAPs, Goswami and her colleagues sought to engineer a GAP that develops in the liver stage for as long as possible before arresting.

Laboratory studies in rodent malaria found late liver stage-arresting GAPs are far superior in generating robust immune responses when compared to early arresting GAPs like GAP3KO. However, translating their results to the human malaria parasite proved challenging.

"A late liver stage-arresting P. falciparum GAP would give us a new gold standard for a malaria vaccine," Goswami said.

Research generates promising late-arresting GAP

Still encouraged by their earlier findings, Goswami continued the search for a gene target that when deleted would allow the human malaria parasite to develop normally in the mosquito, undergo significant replication in liver cells and then arrest late in the liver stage.

In the newly published paper, she and her co-authors describe the results of their search based on a gene they identified in P. falciparum called Mei2.

"Deletion of Mei2 in both the rodent and human malaria strains caused the parasite to arrest very late in liver development," Goswami said. "Importantly, we were still able to produce large numbers of sporozoites, the parasite stage that is at when transmitted from mosquito to human."

The team then tested clones of P. falciparum with the Mei2 GAP in human liver-chimeric mice, a model used to study the human liver in the lab. They found that these GAPs replicated as expected and arrested very late during liver stage development and did not transition to the blood stage, like wild-type parasites without the genetic modification do.

"It's promising to see the sustained prevention of transition to blood stage infection in the lab," Goswami said. "For the first time, we have a viable P. falciparum late liver stage-arresting GAP we hope to advance for malaria vaccine development."

Pursuing a next generation vaccine

Although Goswami cautions that the models used in their studies can't fully mimic how the GAP might behave in an actual human liver, she believes there is sufficient evidence to move the Mei2 GAP vaccine candidate into early phase clinical trials.

"Our research provides the foundation from which we can build a next generation GAP vaccine with potentially increased potency against malaria," she said. "Achieving a higher level of protection while blocking transmission will likely be essential for the ultimate goal of malaria eradication."

Wheat, in its own right, is one of the most important foods in the world. It is a staple food for more than 2.5 billion people, it provides 20% of the protein consumed worldwide and, according to the FAO, supplies more calories than any other grain. Its long-term productivity, however, is threatened by rising temperatures, among other factors. Stress from heat, an increasing trend due to climate change, affects its performance, a fact that needs urgent solutions bearing in mind that, according to some estimates, the world's population will reach 9 billion by the year 2050.

In search of solutions that guarantee this grain's sustainability, an international study, in which the University of Cordoba (UCO) participated, analyzed 54 kinds of wheat made by the International Maize and Wheat Improvement Center (abbreviated to CIMMYT in Spanish), an international research organization located in Mexico. This organization has spent over 60 years developing genetically improved genotypes of wheat and maize.

This research aimed to establish which of the 54 kinds of wheat under analysis responded best to high temperatures. Specifically, according to Carlos Guzmán, lead researcher of the study at UCO, the study revealed that 10 of these genotypes tolerate stress caused by heat better. "Most of them are kinds that have been recently produced by the improvement program, demonstrating the effectiveness of genetic improvement when dealing with this issue if the necessary investment is made", points out the author of the study.

The varieties were grown in the CENEB experimental research station (Sonora, Mexico), cradle of the Green Revolution, where a desert climate prevails. The grain genotypes were planted in February, three months later than normal, in order to have their flowering and grain filling coincide with the hottest months. According to the results, the genotypes that responded best to high temperatures were able to produce 2.4 tons of wheat per hectare, "a farily reasonable amount in this kind of environment and this could help maintain an acceptable rate of productivity under these conditions," says Carlos Guzmán.

This research was not only focused on the amount of wheat the varieties could produce but also on the quality of grain, a factor that very much depends on the quantity and quality of protein and is a key element when marketing the grain to be used in making products such as bread and pasta.

According to the study's results, "the grain quality has not decreased due to stress in any of the ten genotypes that resist heat the best", making these varieties candidates to be used frequently in improvement programs or to be released as varieties in regions and countries where heat stress is common. This is all being done with an aim to generate heat-resistant wheat that can guarantee the sustainability of a staple food that needs to keep on feeding the world.

In collaboration with experimentalists from Ghent University, Belgium and Utrecht University, Netherlands, researchers at the Nanoscience Center (NSC) at the University of Jyväskylä, have recently discovered that the choice of a support material for model catalysts, made from gold nanoclusters protected by organic molecules, may have drastic effects on the structure of the catalyst. On certain supports, the clusters completely disintegrate, while on others, the organic protective layer peels away leaving behind the intact metallic nanoclusters that can act as catalysts for a desired reaction. The research was published in Chemistry-A European Journal (2020).

Catalysts are important to produce chemicals used in our daily lives. They save a lot of energy and make chemical reactions faster as compared to their uncatalysed counterparts.

Nanomaterials, especially metallic nanoclusters are widely used owing to their high efficiency and are generally placed on an inactive oxide support for these applications. However, these nanoclusters are at times less stable, and are protected hence with a layer of organic molecules. The present study is an important step towards the design, control, and synthesis of atomically precise supported catalysts with tailored physical and chemical properties.

Gold nanoclusters (Aun) of different sizes protected by phosphine organic molecules were deposited on four different supports and their properties were measured using X-ray absorption spectroscopy. On Bronsted acid supports (surfaces that have the tendency to give away protons), the clusters were completely fragmented breaking up the Au cluster, while on Lewis acid supports (surfaces that have the tendency to gain electrons) the phosphine organic layer peeled away leaving the metallic Aun cluster preserving the original size of the cluster.

The theoretical models developed in Jyväskylä explained the experimental observations by studying the charge transfer between the support and the clusters.

This study was published in the international publication series Chemistry-A European Journal and recognized as a "hot" paper. An image describing the work was also selected as a cover feature in the journal's recent issue of June 2, 2020.

In Jyväskylä, post doctoral researcher Nisha Mammen, Professor Karoliina Honkala, and Academy Professor Hannu Häkkinen were responsible for the theoretical part of the work. The research was supported by the Academy of Finland. The computer simulations in the study were carried out in the local university supercomputers as well as those of the CSC - IT Center for Science.

Cholesterol levels are declining sharply in western nations, but rising in low- and middle-income nations - particularly in Asia, according to a study of global cholesterol levels, which involve researchers at the University of Gothenburg.

The new study, by hundreds of researchers from across the world was led by Imperial College London and published in the journal Nature. One of the authors is Annika Rosengren, Professor in Medicine at Sahlgrenska Academy, University of Gothenburg.

The research used data from 102.6 million individuals and examined cholesterol levels in 200 countries, across a 39-year time period, from 1980 to 2018.

The work, which was funded by the Wellcome Trust and the British Heart Foundation, revealed that high cholesterol is responsible for about 3.9 million worldwide deaths. Half of these deaths happen in East, South and Southeast Asia.

Cholesterol is a waxy substance found in the blood. The body needs cholesterol to build healthy cells, but too much can lead to a build-up in the blood vessels. Cholesterol comes in different types. High-density lipoprotein (HDL) 'good' cholesterol, which should be 1mmol/L or above, is thought to have a protective effect against heart attack and stroke, by mopping up excess 'bad' cholesterol.

Non-HDL 'bad' cholesterol, which should be as low as possible, can block blood supply and lead to heart attacks and strokes. This type of cholesterol is usually raised by diets high in saturated and trans fats, which is found in many processed foods, instead of healthier unsaturated fats. It can be lowered effectively through the use of statins.

The results of the new study revealed total and non-HDL cholesterol levels have fallen sharply in high income nations, particularly those in North-western Europe, North America and Australasia. Some of the countries where the situation has improved are Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta.

At the same time the levels of non-HDL have been rising in low- and middle-income nations, particularly in East and Southeast Asia. China, which had some of the lowest levels of non-HDL cholesterol in 1980, had one of the largest rates of increase in non-HDL over the 39 year study period. Countries with similar developments are Malaysia, Philippines and Thailand.

The researchers mean that we now need to set into place throughout the world pricing and regulatory policies that shift diets from saturated to non-saturated fats, and to prepare health systems to treat those in needs with effective medicines. This will help save millions of deaths from high non-HDL cholesterol in these regions, they say.

In Sweden the levels of non-HDL in blood decreased by about a third from 1980 to 2018. The average man went from 4.8 mmol/L to 3.5, and the average woman from 4.8 to 3.3. The reduction among women in Sweden was the third largest in the world.

- Non-HDL is a very important risk factor for heart attack, and the strong reduction of non-HDL, together with decreased tobacco smoking, is an important factor for the reduced mortality in heart attack. Between 1987 och 2018 we have seen the mortality in heart attack reduced by 80 percent, Annika Rosengren says.

Despite the active ongoing taxonomic progress on Madagascar's frogs, the amphibian inventory of this hyper-diverse island is still very far from being complete. The known diversity of the diamond frog genus Rhombophryne in Madagascar has increased significantly (more than doubled!) over the last 10 years, but still there are several undescribed candidate species awaiting description. New species are constantly being discovered in Madagascar, often even within already well-studied areas. One such place is the Montagne d'Ambre National Park in northern Madagascar.

Montagne d'Ambre National Park is widely known for its endemic flora and fauna, waterfalls and crater lakes, and considered to be a relatively well-studied area. Yet, only two studies have been published so far on the reptiles and amphibians of the Park.

Serving the pursuit of knowledge of the herpetofauna in the region, Germany-based herpetologist Dr. Mark D. Scherz (Bavarian State Collection of Zoology, Technical University of Braunschweig, University of Konstanz) published a description of a new diamond frog species: Rhombophryne ellae, in the open-access journal Zoosystematics and Evolution.

"As soon as I saw this frog, I knew it was a new species," shares Dr. Scherz, "The orange flash-markings on the legs and the large black spots on the hip made it immediately obvious to me. During my Master's and PhD research, I studied this genus and described several species, and there are no described species with such orange legs, and only few species have these black markings on the hip. It's rare that we find a frog and are immediately able to recognise that it is a new species without having to wait for the DNA sequence results to come back, so this was elating."

The new species is most closely related to a poorly-known and still undescribed species from Tsaratanana in northern Madagascar, but is otherwise quite different from all other diamond frogs. With the orange colouration on its legs, Rhombophryne ellae joins the growing list of frogs that have red to orange flash-markings. The function of this striking colouration remains unknown, despite having evolved repeatedly in frogs, including numerous times in Madagascar's narrow-mouthed frogs alone.

"The discovery of such a distinctive species within a comparatively well-studied park points towards the gaps in our knowledge of the amphibians of the tropics. It also highlights the role that bad weather, especially cyclones, can play in bringing otherwise hidden frogs out of hiding--Rhombophryne ellae was caught just as Cyclone Ava was moving in on Madagascar, and several other species my colleagues and I have recently described were also caught under similar cyclonic conditions", says Dr. Scherz.

The species is known so far only from a single specimen, making it difficult to estimate its conservation status. Yet, based on the status of other, related frogs from the same area, it will probably be Red-listed as Near Threatened due to its presumably small range and micro-endemicity.

As lockdown requirements ease, COVID-19 is changing the way we use indoor spaces. That presents challenges for those who manage those spaces, from homes to offices and factories.

Not least among these challenges is heating and cooling, which is the largest consumer of energy in American homes and commercial buildings. There's a need for smarter, more flexible climate control that keeps us comfortable without heating and cooling entire empty buildings.

Now, a group of researchers at the University of Michigan has developed a solution that could provide more efficient, more personalized comfort, completely doing away with the wall-mounted thermostats we're accustomed to. Human Embodied Autonomous Thermostat, or "HEAT," is detailed in a study published in the July 2020 issue of Building and Environment.

The system pairs thermal cameras with three-dimensional video cameras to measure whether occupants are hot or cold by tracking their facial temperature. It then feeds the temperature data to a predictive model, which compares it with information about occupants' thermal preferences.

Finally, the system determines the temperature that will keep the largest number of occupants comfortable with minimum energy expenditure. The new study shows how the system can effectively and efficiently maintain the comfort of 10 occupants in a lab setting.

"COVID presents a variety of new climate control challenges, as buildings are occupied less consistently and people struggle to stay comfortable while wearing masks and other protective gear," said project principal investigator and study co-author Carol Menassa, associate professor of civil and environmental engineering.

"HEAT could provide an unobtrusive way to maximize comfort while using less energy. The key innovation here is that we're able to measure comfort without requiring users to wear any detection devices and without the need for a separate camera for each occupant."

HEAT works a bit like today's internet-enabled learning thermostats. When it's newly installed, occupants teach the system about their preferences by periodically giving it feedback from their smartphones on a three-point scale: "too hot," "too cold" or "comfortable." After a few days, HEAT learns their preferences and operates independently.

The research team is working with power company Southern Power to begin testing HEAT in its Alabama offices, where test cameras will be mounted on tripods in the corners of rooms. Menassa explains that cameras would be placed less obtrusively in a permanent installation. The cameras collect temperature data without identifying individuals, and all footage is deleted immediately after processing, usually within a few seconds.

A second test, also with Southern Power, will place the system in an Alabama community of newly constructed smart homes. The team estimates that they could have a residential system on the market within the next five years.

Facial temperature is a good predictor of comfort, Menassa said. When we're too hot, the blood vessels expand to radiate additional heat, raising facial temperature; when we're too cold, they constrict, cooling the face. While earlier iterations of the system also used body temperature to predict comfort, they required users to wear wristbands that measured body temperature directly, and to provide frequent feedback about their comfort level.

"The cameras we're using are common and inexpensive, and the model works very well in a residential context," said study co-author Vineet Kamat, U-M professor of civil and environmental engineering, and electrical engineering and computer science. "Internet-enabled thermostats that detect you and learn from you have sort of built a platform for the next phase, where there's no visible thermostat at all."

HEAT's predictive model was built by U-M industrial operations and engineering associate professor Eunshin Byon, who is also an author on the study. She believes that tweaks to the model could make the system useful in applications beyond homes and offices--in hospitals, for example, where care providers struggle to stay comfortable under masks and other protective equipment.

"The COVID-19 pandemic requires nurses and other hospital workers to wear a lot of protective gear, and they've struggled to stay comfortable in the fast-faced hospital environment," Byon said. "The HEAT system could be adapted to help them stay comfortable by adjusting room temperature or even by signaling to them when they need to take a break."

In partnership with the U-M school of nursing, Menassa's research group has already conducted a pilot study that explored how the system can be used to provide personalized thermal comfort for nurses working in healthcare environments such as chemotherapy administration units.

Bloomington, Ind. and Chicago, Ill. -- Results from a new study show that risk factors for cardiovascular disease and diabetes were similar when participants consumed a healthy US-style eating pattern with and without an additional 5.3 ounces of lean beef. The added beef replaced carbohydrates, primarily refined starches. All participants were considered at risk for type 2 diabetes and followed a healthy diet as outlined by the 2015 U.S. Dietary Guidelines for Americans, and separately a similar diet modified to have a larger portion of calories from lean beef in random order.

"Most indicators of metabolic and cardiovascular health, such as insulin sensitivity and LDL cholesterol, did not differ between the two diets. The only significant difference observed was a shift toward a greater percentage of cholesterol carried in larger, more buoyant LDL particles during the higher beef condition. This difference is potentially important because larger, more buoyant LDL particles may be less likely to promote atherosclerosis," said Kevin C. Maki, Ph.D., who was the Study Director and is Adjunct Professor in Applied Health Science at the Indiana University School of Public Health-Bloomington.

"This study is important because it shows that red meat can be part of a healthy eating pattern," said Dr. Maki, "Our study compared US-style healthy eating patterns with red meat intake that was below-average for the United States (about 1.2 ounces per day), versus a similar diet that contained an additional 5.3 ounces per day of unprocessed, lean beef. All foods consumed by the subjects during each diet period were provided by the research team." The 33 study participants (26 women and 7 men) completed the crossover, controlled-feeding trial, where each subject was randomly assigned to follow one eating pattern for 4 weeks, followed by a washout of 2 weeks, then consumption of other diet for 4 weeks.

Beef is a nutrient-dense food with high quality protein, iron and zinc, but results from some observational studies have suggested that red meat consumption is associated with increased type 2 diabetes and cardiovascular disease incidence. "Our study showed that increasing intake of lean beef, as a replacement for refined starches in a healthy diet, did not worsen cardiometabolic risk factors. While this research is important for those who choose to include red meat in healthy diets, we are not encouraging people to increase red meat consumption or advocate that those who would otherwise consume a vegetarian-style eating pattern to begin eating red meat."

Social media sites aren't the only things that keep track of your social network -- your brain does, too. But loneliness alters how the brain represents relationships, according to new research published in JNeurosci.

A brain region called the medial prefrontal cortex (mPFC) maintains a structured map of a person's social circles, based on closeness. People that struggle with loneliness often perceive a gap between themselves and others. This gap is reflected by the activity patterns of the mPFC.

Courtney and Meyer used functional magnetic resonance imaging to examine participants' brain activity while they thought about the self, close friends, acquaintances, and celebrities. Thinking about someone from each category corresponded to a different activity pattern in the mPFC: one for the self, one for the social network (both friends and acquaintances), and one for celebrities. The closer the relationship, the more the pattern resembled the pattern seen when thinking about the self.

These brain patterns differed for lonelier individuals. Activity related to thinking about the self was more different from activity related to thinking about others, while the activity from thinking about others was more similar across social categories. In other words, lonelier people have a "lonelier" neural representation of their relationships.

What The Study Did: This is a quality improvement study that examines the effects of sterilization with hydrogen peroxide and chlorine dioxide on the filtration efficiency of N95, KN95 and surgical face masks.

Authors: Changjie Cai, Ph.D., of the University of Oklahoma Health Sciences Center in Oklahoma City, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2020.12099)

Editor's Note: The article includes funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflicts of interest and financial disclosures, and funding and support.

Boston, MA - Greater adherence to a variety of healthy eating patterns was associated with a lower risk of cardiovascular disease (CVD), according to new research led by Harvard T.H. Chan School of Public Health. The findings add support for the 2015-2020 Dietary Guidelines for Americans, which focus on healthy eating patterns rather than individual ingredients and nutrients to better account for diverse cultural and personal food traditions and preferences.

"Although each healthy eating pattern represents a different combination of dietary constituents, our study indicates that greater adherence to any of the four healthy eating patterns we looked at is associated with lower risk of cardiovascular disease and the health benefits persist across racial and ethnic groups," said Zhilei Shan, first author on the paper and a research associate in the Department of Nutrition.

The study will be published online in JAMA Internal Medicine on June 15, 2020.

Few studies have examined how adhering to recommended healthy eating patterns influence long-term risk of CVD. For this study, researchers focused on dietary scores for four healthy eating patterns: Healthy Eating Index-2015 (HEI-2015); Alternate Mediterranean Diet Score (AMED); Healthful Plant-Based Diet Index (HPDI); and Alternate Healthy Eating Index (AHEI). Despite different scoring methods, each of these patterns emphasizes higher intake of whole grains, vegetables, fruits, legumes, and nuts, and lower intakes of red and processed meats and sugar-sweetened beverages.

To assess the associations of each pattern with CVD risk, the researchers looked at data from 74,930 women enrolled in the Nurses' Health Study, 90,864 women in the Nurses' Health Study II, and 43,339 men in the Health Professionals Follow-Up Study. Participants in each study were asked every two to four years about their dietary habits, including how often, on average, they consumed a standard portion size of various foods.

Using the dietary data, which was collected over several decades via validated dietary questionnaires, the researchers created four dietary scores for each participant. Higher dietary scores represented greater adherence to healthy eating patterns. After adjusting for numerous factors, including age, BMI, and smoking status, the analysis found that greater adherence to any of the healthy eating patterns was consistently associated with lower risk of CVD. The study found that participants who adhered most to healthy eating patterns (those in the top quartile of the scores) had a 14% to 21% lower risk of CVD when compared with those who adhered least (in the bottom quartile of the scores).

The findings also showed that these different healthy eating patterns were similarly effective at lowering CVD risk across racial and ethnic groups and other subgroups studied, and that they were statistically significantly associated with lower risk of both coronary heart disease and stroke.

"These data provide further evidence to support current dietary guidelines that following healthy eating patterns confers long-term health benefits on cardiovascular disease prevention," said corresponding author Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition. "There is no one-size-fits-all diet that is best for everyone. One can combine foods in a variety of flexible ways to achieve healthy eating patterns according to individuals' health needs, food preferences, and cultural traditions."

By analysing the different layers of bacterial gene expression during pathogen infection of a plant host, Kenichi Tsuda and colleagues from the Max Planck Institute for Plant Breeding Research in Cologne, Germany and Huazhong Agricultural University in Wuhan, China have revealed new insights into bacterial gene regulation as well as the strategies employed by plants to target key bacterial processes.

Bacterial pathogens and their plant hosts engage in complex interactions mediated by changes in the expression of bacterial virulence and plant immune components. Understanding this interplay is critical for an integrated understanding of how bacteria cause disease and how plants protect themselves from infection. However, studies examining the response of pathogenic bacteria to plant immune activation have been few and far between owing to two main bottlenecks. One challenge with profiling bacterial responses inside their plant hosts is isolating bacterial RNA, the molecule that transfers the genetic information from the DNA blueprint to active proteins, from the large sea of plant material. To overcome this obstacle, first authors Tatsuya Nobori, Yiming Wang and colleagues made use of their own previously established method for enriching bacterial RNA from plant leaves. However, levels of RNA are often poor predictors of protein levels, and to tackle this problem, Nobori, Wang, and co-workers analysed both the expression of RNA as well as protein and correlated these with each other.

To analyse bacterial gene expression patterns during infection, the authors used the well-characterised bacterial pathogen Pseudomonas syringae and the model plant Arabidopsis thaliana. Nobori, Wang, and co-workers found large differences between both RNA and protein levels of P. syringae when they were inoculated into plants compared with bacteria grown in the lab, particularly early during the plant-bacterial interaction, which suggests that these early patterns of bacterial gene expression are crucial for the outcome of infection.

To determine the role of plant immunity in shaping bacterial gene expression, the authors made use of mutant plants in which specific branches of the immune system were compromised and analysed the different categories of genes whose expression was affected. This analysis showed that plant immune signalling controlled by the hormone salicylic acid (SA) suppresses bacterial mRNAs and proteins that promote pathogenesis.

The authors' collection of bacterial RNA and protein expression data allowed them to determine the impact of the SA pathway on bacterial mRNAs and/or proteins during bacterial infection. They observed a generally high level of agreement, which suggests that the SA pathway targets bacterial mRNA expression. Notably, they also found that the SA-mediated arm of plant immunity specifically targets proteins that form the tip of an 'injector' used by bacteria to deliver their virulence proteins inside host cells and that the same branch of plant immunity also highly suppresses protein but not mRNA expression of factors related to bacterial movement.

The wealth of expression data generated by the Tsuda and his team also allowed them to address how individual bacterial genes are regulated during infection. To do this, they correlated the expression of over 4,500 genes with each other and clustered together those genes that exhibit similar patterns of expression. This approach yielded two important insights: first, the co-expression analysis allowed them to identify previously unknown bacterial gene clusters that contribute to bacterial growth; second, by observing that groups of highly co-expressed genes also contained known transcriptional regulators of these clusters, the authors could successfully predict previously unknown transcriptional regulators and validate that these did in fact control bacterial gene expression and virulence.

Co-first author Nobori emphasises that the authors' approach for analysing the flow of bacterial genetic information during plant infection can potentially also be applied to the interactions of crop species with pathogenic bacteria: "Identifying the tactics used by bacteria to establish infection as well as plant counterstrategies would suggest interventions for optimizing crop breeding."

New research published in the journal Coral Reefs revealed unexpectedly high growth rates for deep water photosynthetic corals. The study, led by Samuel Kahng, affiliate graduate faculty in the University of Hawai'i at Mānoa School of Ocean and Earth Science and Technology (SOEST), alters the assumption that deep corals living on the brink of darkness grow extremely slowly.

Leptoseris is a group of zooxanthellate coral species which dominate the coral community near the deepest reaches of the sun's light throughout the Indo-Pacific. Symbiotic microalgae (called zooxanthellae) live within the transparent tissues some coral--giving corals their primary color and providing the machinery for photosynthesis, and in turn, energy.

Deeper in the ocean, less light is available. At the lower end of their depth range, the sunlight available to the Leptoseris species examined in the recent study is less than 0.2% of surface light levels. Less light dictates a general trend of slower growth among species that rely on light for photosynthesis.

Previous studies suggested that photosynthetic corals at the bottom of the ocean's sunlit layer grow extremely slowly - about 0.04 inch per year for one species of Leptoseris. Until recently, there were very few data on growth rates of corals at depths greater than about 225 feet given the logistical challenges of performing traditional time series growth measurements at these depths.

Kahng, who is also an associate professor at Hawai'i Pacific University, collaborated with SOEST's Hawai'i Undersea Research Laboratory (HURL), the Waikiki Aquarium, National Taiwan University and Hokkaido University to collected colonies of Leptoseris at depths between 225 and 360 feet in the Au'au Channel, Hawai'i using HURL's Pisces IV/V submersibles. The research team used uranium-thorium radiometric dating to accurately determine the age of the coral skeletons at multiple points along its radial growth axis - much like one might determine the age of tree rings within a tree trunk.

"Considering the low light environment, the previous assumption was that large corals at these extreme depths should be very old due to extremely slow growth rates," said Kahng. "Surprisingly, the corals were found to be relatively young with growth rates comparable to that of many non-branching shallow water corals. Growth rates were measured to be between nearly 1 inch per year at 225 feet depth and 0.3 inches per year at 360 feet depth."

The research team found that these low light, deep water specialists employ an interesting strategy to dominate their preferred habitat. Their thin skeletons and plate-like shape allow for an efficient use of calcium carbonate to maximize surface area for light absorption while using minimal resources to form their skeleton. These thin corals only grow radially outward, not upward, and do not thicken over time like encrusting or massive corals.

"Additionally, the optical geometry of their thin, flat, white skeletons form fine parallel ridges that grow outward from a central origin," said Kahng. "In some cases, these ridges form convex spaces between them which effectively trap light in reflective chambers and cause light to pass repeatedly through the coral tissue until it is absorbed by the photosynthetic machinery."

The strategic efficiency of Leptoseris enabling its robust growth rates in such low light has important implications for its ability to compete for space and over-shade slower growing organisms.

"It also illustrates the flexibility of reef building corals and suggests that these communities may be able to develop and recover from mortality events much faster than previously thought," said Kahng.

Polarization, conspiracy theories, fake news: What people see on the Internet is largely determined by the opaque algorithms of just a few corporations. That's a worrying development for democratic societies. But online environments could be designed in ways that promote autonomy and transparency, thereby fostering the positive potential of the Internet. A team of researchers from the Max Planck Institute for Human Development in Berlin, the University of Bristol, and Harvard Law School has approached this debate from the behavioral science perspective and proposed interventions capable of promoting a more democratic Internet. Their findings have been published in Nature Human Behaviour.

You're scrolling through your YouTube, Facebook, or Twitter feed when a video appears: a report on secret political deals, media conspiracies, or fake scientific studies. Everything seems to be backed up by facts. The video has hundreds of thousands of clicks and appears to be gaining traction worldwide. And plenty of viewers seem to agree with it, having given it a "thumbs up." But what exactly does all this mean? Does it make the video credible? How many viewers watched the video to the end; how many left midway? And why did the video appear in your feed in the first place? The online platform knows many of the answers, but it doesn't share that information. And no other cues are provided that could help you to assess the content, quality, or credibility of the video.

According to the Reuters Institute Digital News Report 2019, more than half (55%) of the world's Internet users now use social media or search engines to keep up with the news. In other words, public opinion is shaped largely by online content, which is in turn curated by algorithms. "The aim is to keep users happy for as long as possible so that they stay on the platform. That's achieved by providing entertainment and establishing a feeling of well-being -- which probably explains why many platforms don't have 'dislike' buttons that allow users to downvote content. The feeling being conveyed is: You're right. That may be harmless when we share private content such as holiday photos, but it distorts the picture when what's being spread are radical opinions and untruths," says co-author Stephan Lewandowsky, Professor of Cognitive Psychology at the University of Bristol.

Another problem is that newsfeed algorithms only show users content thatbased on their previous online behavior -- they are likely to agree with. Other points of view tend not to be shown at all. This creates networks of like-minded users, which reinforce shared opinions and create the illusion of broad support, even if an opinion is actually not widely held. But how can users distinguish fake news from facts? And how do online environments need to be designed to support these efforts? "The interventions we propose are aimed at empowering individual users to make informed and autonomous decisions in online environments --- ideally, without having to rely on independent fact checkers. The architecture of online environments influences users' behavior. To change that environment for the better, we need to understand human behavior and take that behavior into account in design choices," says Philipp Lorenz-Spreen, lead author of the study and researcher at the Max Planck Institute for Human Development.

The research team has identified a number of ways to help users evaluate the quality of Internet content and to understand the mechanisms behind algorithms -- without curtailing the freedoms central to the original philosophy of the Internet. These possibilities are technologically feasible but so far largely untapped. The research team has developed specific recommendations to empower individuals online, drawing on two approaches from the behavioral sciences: nudging and boosting.

Nudging aims to steer people's behavior by highlighting important information without imposing rules or bans. Boosting aims to enhance people's decision-making competence, enabling them to navigate situations autonomously and make better decisions. According to the researchers, it is important to take a multi-pronged approach to reach as many people as possible. Nudging could be used, for example, to indicate whether content meets certain quality criteria -- such as whether it stems from trustworthy sources. This would both prompt users to check content thoroughly and create an incentive structure for content producers to meet the required criteria. Including hyperlinks to verified sources would be another step. Wikipedia could serve as a model here: The references and cross-references it provides help to contextualize the information presented. Twitter recently took a step in this direction and started flagging some tweets with a fact-check warning -- including a tweet by Donald Trump on the subject of postal voting.

Nudges could also communicate additional information about other users' online behavior, giving further context on how others evaluate content. For example, the number of likes could be set in relation to the total number of readers: "4,287 out of 1.5 million readers liked this article." The information that there were 44,000 clicks on an article, but that only 3,000 users read it to the end could be a better indicator of quality than numbers of clicks and likes alone. It has been shown that transparent numerical formats can improve medical decisions. Why shouldn't the same apply to the Internet? This approach could prevent the formation of echo chambers in which groups of people wrongly believe that their opinion is widespread and accepted.

Another possibility might be to make it slightly more difficult for users to share information when an article fails to cite external references. For example, users might be required to click past a pop-up window containing a warning that references are missing. Another type of nudge might target how content is arranged in browsers -- that is, the way a newsfeed sorts content. Clearly differentiating between types of content, such as opinions, news, or posts by friends, can make newsfeeds more transparent.

Boosting, in contrast, aims to enhance user competence in the long term. This could, for instance, mean enabling people to adjust how their newsfeeds are sorted--letting them change their settings to reflect which factors are most important to them and which content they want to see first. Social networks could be obliged to indicate why some content is weighted more heavily and shown first, while other content is given lower priority. Another example of a boost would be to present the original source of a piece of information and the route by which it reached a user. Simple decision trees could guide users through a step-by-step process of checking the origin, context, and quality of online content. In other words, users would be given the tools to become fact checkers themselves. In the long term, they would learn to recognize patterns, to critically assess content, and to identify manipulation more quickly.

"The interactive nature of social media could be harnessed to promote diverse democratic dialogue and foster collective intelligence. Our aim is to find ways to strengthen the Internet's potential to inform decision-making processes in democratic societies, bolstering them rather than undermining them. Global problems like climate change and the coronavirus pandemic require coordinated, collective solutions. And that makes a democratically interconnected online world crucial," says Ralph Hertwig, Director of the Center for Adaptive Rationality at the Max Planck Institute for Human Development.

Researchers discover what's behind nature's perhaps largest erection - which is not that big
PLANT BIOLOGY In the plant kingdom, the sexual organ of a male pollen grain grows up to a thousand times its own length as it sniffs its way forth to a female egg cell to deliver its two sperm cells. Now researchers at the University of Copenhagen have advanced the understanding of what makes pollen 'penises', called pollen tubes, grow. The newfound knowledge may prove valuable to understanding human nerve cells.

Pollenrube

Microscopic photo of a normal pollentube and a pollentube with essential growth-genes turned off. The black line is a scale for 0.1 mm.

There's no need for Viagra among 'males' in the plant kingdom. When a male pollen grain, transferred by wind or insects, reaches the female part of a flower, a long, sperm cell-containing tube grows out of it. This tube, known as a pollen tube, can extend several thousand times its own length.

Exactly how this erection works has been unclear for more than 100 years. But now, researchers at the Department of Plant and Environmental Sciences at the University of Copenhagen have learned what drives pollen tube growth: an electrical circuit, powered by microscopic pumps known as 'proton pumps'. The study has just been published in Nature Communications.

"We were taken aback by how extremely advanced the plant's fertilisation mechanism really is. From textbooks, we understand that pollen tubes grow and push forth by continually building additional floors upon the cell skeleton, like a growing scaffold. However, very little was known about the underlying mechanisms of this enormous growth. Our work has made the world a bit wiser," says Professor Michael Broberg Palmgren from the Department of Plant and Environmental Sciences.

Sniffing its way, up to three millimetres a day

Like a sniffer dog, the pollen tube smells its way to an egg cell buried within the female structure, that will eventually become a seed. Tube growth occurs as it continuously extends its tip, a process called 'tip growth'. Pollen tube growth reached roughly three millimeters a day in the thale cress, a weed plant, used in the study.

"The pollen tube is not a rigid tube. It is dynamic and can redirect as it searches for an egg," explains Michael Broberg Palmgren.

Watch video (not from this study) of a pollentube searching for the female pollen.

The researchers discovery was made by manipulating a group of genes called AHA in the small plant. These genes are what make it possible for plants to produce the so-called 'proton pumps' that control a pulsed acid-base balance in the pollen tube and generate electrical voltage across its cell membrane. Suspecting that these genes played a role in pollen tube growth, the researchers began 'switching off' some of the genes in various combinations.

"In experiments, we were able to see that the 'mutant pollen tubes', in which we had switched off the genes, were dramatically delayed in their growth and had difficulty finding their way," explains Professor Palmgren.

Result could apply to human nerve growth

Being fundamental research, concrete applications of the result remain unclear. But the new knowledge of how pollen tubes grow by prolonging their tips - 'tip growth' - could be transferable to humans.

"Very little is known about what controls nerve growth -- which is hugely important for recovery from nerve or brain damage. Here, our result might prove useful for better understanding the process of 'tip growth', which is how the human nervous system grows as well," says Palmgren.

The professor points out that plant fertilization - and plants in general -- are still not entirely understood by researchers.

"The more we investigate, the more advanced plants turn out to be. There are no arguments to suggest that plants are any less than us humans."

The research was funded with funding from the Center for Membrane Pumps in Cells and Disease (PumpKin), as part of a larger grant for broad basic research on pumps from the Danish National Research Foundation.