Culture

A team of scientists, led by the University of Bristol, has developed a new photosynthetic protein system enabling an enhanced and more sustainable approach to solar-powered technological devices.

The initiative is part of a broader effort in the field of synthetic biology to use proteins in place of man-made materials which are often scarce, expensive and can be harmful to the environment when the device becomes obsolete.

The aim of the study, published today in Nature Communications, was the development of "chimera" photosynthetic complexes that display poly-chromatic solar energy harvesting.

For the first time, the scientists were able to build a single protein system that uses both chlorophyll and bacteriochlorophyll, and in doing so have demonstrated the two pigment systems can work together to achieve solar energy conversion.

Lead author of the study and Reader in Biochemistry at the University of Bristol, Dr Mike Jones, said:

"In the past, two main types of protein have been used for solar energy conversion in technological devices. The first are from 'oxygenic' photosynthetic organisms -plants, algae and cyanobacteria - that contain chlorophyll as their main photosynthetic pigment and produce oxygen as a waste product of the process. The second are from 'anoxygenic' organisms, bacteria that contain bacteriochlorophyll as their primary photosynthetic pigment.

"We have assembled these two proteins, from very different parts of the photosynthetic world, into a single biological photosystem that enables expanded solar energy harvesting. We have also demonstrated that this system can be interfaced with man-made electrodes to achieve expanded solar-to-electric conversion."

The scientists, from the University's BrisSynBio Institute, in collaboration with photoelectrochemistry colleagues at the Free University Amsterdam, purified a 'reaction centre' protein from a purple-coloured photosynthetic bacterium and a light-harvesting protein from a green plant (actually made recombinantly in E. coli) and locked them permanently together using a linking domain taken from a second bacterium. The result is the first single complex with a well-defined protein and pigment composition that shows expanded solar energy conversion.

The BBSRC and EPSRC-funded study was largely the work of Dr Juntai Liu, a PhD student in the University of Bristol's Centre for Doctoral Training in Synthetic Biology. This breakthrough is an example of a synthetic biology approach, treating proteins as components that can be assembled in new and interesting ways using a common and predictable interface.

"This work shows that it is possible to diversify the protein systems which can be built into devices beyond those which nature supplies, using a simple approach achieved purely through genetic encoding," said Dr Jones.

Dr Jones said the next step was to expand the palette of photosynthetic pigments, using proteins from cyanobacteria that contain bilin pigments that absorb yellow and orange light, and to explore linking enzymes to these novel photosystems in order to use sunlight to power catalysis.

Osaka, Japan - Despite its small size relative to the rest of the body, the eye is one of the most complex organs of the human body and has been difficult to study in a lab. Now, researchers from Osaka University have developed a novel method to model eye development and disease using human induced pluripotent stem cells (hiPSCs). In a new study published in Journal of Biological Chemistry, they showed how tracking the expression of PITX2, a key protein during eye development, in developing hiPSCs enables the isolation of a certain group of cells that play important roles in eye development, biology and disease.

Ever since their discovery over a decade ago, hiPSCs have continued to be used to replicate human biology and disease in a lab without the need for animals. Their streamlined use is accompanied by the possibility of easily genetically altering the cells to study the function of proteins. Although to date several cellular models of multiple organs have been developed using hiPSC, due to its complex and heterogeneous nature, the eye has been more difficult to recreate using these cells.

"Unlike other organs, the eye is more difficult to recreate in the lab due to the presence of heterogeneous cells in the eye," says corresponding author of the study, Ryuhei Hayashi. "The goal of our study was to develop a novel human cellular eye model using hiPSCs that will help improve our understanding of how these different cell types develop to form the eye."

To achieve their goal, the researchers established a reporter cell line by modifying hiPSCs using genome editing technology, such that the cells express the fluorescent protein eGFP whenever they express the protein PITX2. PITX2 is a transcriptional factor protein that plays a key role during embryonic development of several organs, including the eyes. In the eye, PITX2 is specifically expressed in what is called periocular mesenchyme (POM), a collection of cells that give rise to the cornea, as well as muscle cells and connective tissue within the eye. As a result, by using the genetically modified cells, the researchers were able to fluorescently label POM cells.

"We wanted to know whether our new cellular model was able to recreate elements of normal eye development and isolated POM cells for characterization," says lead author of the study Toru Okubo.

The researchers first showed that the modified hiPSCs remained pluripotent after genome editing, so they still maintained the properties of pluripotent stem cells in the same way as unchanged hiPSCs. They then induced the development of POM cells from hiPSCs and showed that they formed so-called self-formed ectodermal autonomous multi-zones (SEAM), which are two-dimensional tissues consisting of different eye cells that form during normal eye development (first reported by Hayashi's group in 2016). Previously, there were no methods to isolate POM cells, but this new generation of gene-edited iPSCs enables the team to isolate POM cells selectively from the SEAM. By isolating the fluorescent POM cells from other, non-fluorescent cells, the researchers were then able to show that POM cells maintained known molecular markers during further cell culture, validating the recreation of eye development using their hiPSC reporter cell line.

"These are striking results that show how human stem cells can be used to study development and disease processes," says Hayashi. "Our model could offer a new opportunity to understand how different aspects of eye development happen."

Researchers from Curtin University have used next generation DNA sequencing to learn more about the different species of plants, insects and animals present in the Pilbara and Perth regions of Western Australia.

Lead researcher Curtin PhD candidate Mieke van der Heyde, from the ARC Centre for Mine Site Restoration said that DNA metabarcoding is a growing field in the biological monitoring space, with the potential to provide fast, accurate, and cost effective assessments of biodiversity.

"Traditionally, biomonitoring has relied on scientists setting traps and visually monitoring a certain area, counting the number of species, and then extrapolating that data to come up with regional analysis," Ms van der Heyde said.

"Understandably, that method of data collecting is expensive, time consuming and challenging, especially when looking into remote areas of Australia, which often present a harsh climate.

"As animals and organisms interact with their environment, they leave behind traces of their DNA through things like droppings, skin cells, saliva, and pollen. When this DNA is found in the environment, it's known as environmental DNA, or eDNA.

"Our research looked in to the feasibility of using this eDNA as an additional tool for biomonitoring. Not only to see if this type of analysis could potentially make things a bit easier for biologists out in the field, but as well as providing researchers with more accurate field information then what they can visually identify."

The study analysed samples of soil, animal droppings, plant and insect material, collectively known as 'substrates,' taken from two different areas of Western Australia: The Pilbara, a hot desert climate, and the Swan Coastal Plain, a hot Mediterranean-type climate.

"We tested common environmental substrates including soil, bulk scat, bulk plant material, and bulk arthropods from pitfall traps and vane traps, using four eDNA barcoding assessments to detect a wide range of plants, vertebrates and arthropods," Ms van der Heyde said

"This study was the first of its kind to systematically test terrestrial substrates for eDNA, and it also was the first time that some of these particular substrates were analysed.

"Results show that bulk arthropods and animal droppings detected the most biodiversity, with at least a third of the biodiversity detected in only one substrate. Soil samples detected the least, and fewer samples had usable DNA, especially in the Pilbara. We believe this is most likely due to the hot climate, which potentially degraded the eDNA.

"Biomonitoring is necessary for effective ecosystem management. Our study shows that eDNA can detect biodiversity in an area, and collecting more substrates will increase the breadth of biodiversity detected.

"However, surveys must be carefully considered, as DNA may come from organisms outside the study area," Ms van der Heyde said.

In the production of compounds, chemists have the fundamental goal of finding strategies that are most selective and avoid waste products. Breakthroughs in this area serve, among other things, to drive industrial innovation and drug development. In this context, allylic substitution reactions using catalysts made of so-called transition metals have already led to significant advances in science. The catalysts cause that in a molecule a functional group is replaced by another group in allylic position, i.e. in direct proximity to a carbon-carbon double bond.

In particular, the so-called allylic functionalization by means of a catalyst based on the transition metal palladium has become a well-established strategy for constructing carbon-carbon or carbon-heteroatom bonds, and its utility has been demonstrated in natural product synthesis, drug discovery and materials science. Nevertheless, there are still considerable challenges in practice, especially with regard to the sustainability of the substances and their ability to undergo chemical reactions.

Now a team of researchers led by Prof. Frank Glorius from the University of Münster (Germany) has developed a new approach to allyl functionalization and generated π-allylpalladium complexes using radical chemistry. The study has been published in the journal "Nature Catalysis".

Several methods had been developed to generate π-allylpalladium complexes through ionic mechanisms before; however, these methods typically require either prefunctionalized starting materials or stoichiometric oxidants, which naturally limits their scope. "This is the first time to achieve the π-allylpalladium complexes using a radical strategy. We hope that this radical strategy will be quickly adopted by the synthetic community and used as a complementary method to enable a number of other related reactions," Prof. Frank Glorius states.

This is how the new method functions: A commercially available palladium catalyst is photoexcited by visible light, merging N-hydroxyphthalimide esters derived from inexpensive and abundant aliphatic carboxylic acids and feedstock butadiene, enabling to generate π-allylpalladium complexes. This leads to a so-called 1,4-aminoalkylation of the dienes, which the scientists were able to show across more than 60 examples. Moreover, they could demonstrate the utility of this strategy in radical cascade reactions and in the modification of drugs and natural products.

"This is an innovation in Palladium chemistry, we taught this old transition metal catalyst new tricks. Additionally, readily available N-hydroxyphthalimide esters were employed as bifunctional reagents, killing two birds using one stone," says Dr. Huan-Ming Huang, first author of the study.

A team of neuroscientists at Max Delbrueck Center for Molecular Medicine in the Helmholtz Association (MDC) have made an unexpected discovery about the way mice perceive warming sensations. It's counterintuitive: cooling receptors in the skin are critical for the perception of warmth.

The finding, recently published in the journal Neuron, challenges the predominant model of non-painful temperature perception, and provides clues about the way not just mice, but also humans, consciously detect warmth.

"When we grab a cup of coffee with our hands, and we can quickly feel its warmth, this is happening because not only neurons activated by warming are at play, but also neurons inactivated by it," said Ricardo Paricio-Montesinos, co-first paper author and neuroscientist from the MDC. "Without the second type, our data from mice suggest that we would either need much longer to feel it or perhaps we wouldn't even sense warming at all."

A mysterious sensation

Since the late 1800s, neuroscientists have theorized that dedicated pathways or "labeled lines" convey only warm or only cool sensations from the skin to the brain. While there has been some evidence of this in humans and primates, it has been difficult to prove.

Professor Gary Lewin, who heads MDC's Molecular Physiology of Somatic Sensation Lab teamed up with Dr. James Poulet, who heads MDC's Neural Circuits and Behavior Lab to study non-painful temperature perception in mice. "Temperature is still a mysterious sensation," Poulet said. "It is very understudied, especially compared to vision, touch or hearing."

The mouse's ability to perceive non-painful temperature changes has not been closely investigated. Through a series of behavioral studies, they discovered that mice detect temperature changes with same high level of acuity as humans - licking a water dispenser in response to 1ºC of warming and 0.5ºC of cooling.

"For the first time, we could show that mice basically feel warmth and cooling just exactly the same as we do," Lewin said. "They have the exact same thresholds as humans."

A bigger surprise

When neural pathways thought to be associated with warming were blocked, the mice would lick the dispenser in response to 2ºC of warming, revealing perception was diminished but not gone. This indicates those pathways are helpful, but not essential to perceive warmth. In contrast, when the pathway associated with cooling was blocked by turning off the trmp8 gene, the mice could not perceive warmth at all.

"We were really surprised," said Dr. Frederick Schwaller, co-first author and post-doc in the Lewin Lab. "We initially tried to train these mice to detect skin warming as a control, but we stumbled on the most important finding in the paper sort of by chance."

Upon closer inspection of nerve cells in the forepaw, the researchers observed two things. First, no nerve cells were solely dedicated to warming. Rather, they found most nerve cells fired an electrical signal in response to temperature and blunt pressure.

"That is puzzling," Lewin said, "How does the nervous system figure out if the neuron's activity is because of warm, cold or mechanical force?"

The answer lies in the second thing the team found: a population of nerve cells that are always firing at the forepaw baseline temperature of 27ºC. As the temperature rises, these cells decrease their activity. That decrease appears to be the key.

Compared, not labelled

The team theorizes that the mouse is able to detect warmth because one population of neurons increases activity, while the cool neurons decrease activity. Two signals going in opposite directions generates a pattern that conveys "warm" to the brain. This is distinct from cooling, in which all the neurons increase activity, so the pattern is all going in the same direction.

"The use of two populations makes it much easier for the mouse to unambiguously say that's warming, that's cooling," Lewin said.

When the cooling pathway was blocked, the cool cells were silent and no activity was transmitted to the brain. Without that contributing to an opposite signal pattern, the mice did not perceive warmth, the researchers conclude.

The researchers anticipate the mouse's sensations reflect what is happening in humans because we have the same receptors and nerves that convey information from the skin to the spinal cord and brain. Further studies will be required to confirm humans exhibit the same pattern, and to determine where and how the signals are compared in the brain or spinal cord.

Scientists have revealed an important mechanism in the repair of DNA double-strand breaks, according to new research published today in eLife.

The discovery will help our understanding of why DNA repair processes do not work properly in some people, causing inherited diseases and cancer.

One of the main DNA repair processes is called homologous recombination (HR). This repairs a severe form of DNA damage where both strands of DNA are broken. A protein called Rad51 orchestrates HR, and Rad51 itself is supported by several 'helper' proteins.

"We already know that a group of helper proteins can be sub-grouped into two modules, and that each module has a different role," says lead author Bilge Argunhan, a researcher in senior author Hiroshi Iwasaki's lab at the Tokyo Institute of Technology, Japan. "In this study, we aimed to understand exactly how Module 1 interacts with Rad51 and how the two modules cooperate to switch on Rad51."

The researchers started by using yeast cells to study Rad51 and its helper proteins, called Swi5-Sfr1. They genetically engineered yeast cells so that they lacked either Module 1 or Module 2 of Swi5-Sfr1 and found that this prevented DNA repair by HR. This shows that both modules are needed for Rad51 to switch on HR repair.

Next, they purified the Swi5-Sfr1 helper proteins from cells to identify the precise regions within Module 1 that attach to Rad51. Then, by mutating the protein sequence, they were able to modify these regions in a way that prevents Swi5-Sfr1 from attaching to Rad51. Surprisingly, they found that although the mutated helper proteins could not switch on Rad51 in a test tube, yeast cells with these mutations were still able to repair their DNA without problems. This led the team to speculate that another group of helper proteins, which are present in the cell but absent in the test tube, was rescuing the DNA repair process.

Previous genetic studies have shown that there are two HR sub-pathways in yeast - one that depends on Swi5-Sfr1 and another that relies on molecules called Rad51 paralogs. To test whether it was this other HR pathway that was rescuing DNA repair, the team used yeast that lacked the Rad51 paralogs. The results were striking: in yeast with mutant Swi5-Sfr1 and no Rad51 paralogs, the DNA damage was much more severe. This suggests that the damaging effects of mutations to the Swi5-Sfr1 helper complex are suppressed by a second group of helper proteins.

"Although these two groups of helper proteins were previously thought to function independently, our study shows that they actually work together to activate Rad51 in DNA repair," explains senior author Hiroshi Iwasaki, Professor at the Tokyo Institute of Technology. "The fundamental mechanisms of DNA repair are highly conserved from yeast to humans. Our new insight into DNA repair in yeast may serve as a template for understanding why DNA repair processes do not function properly in human disease."

The former coalfield of Geiseltal in Saxony-Anhalt has yielded large numbers of exceptionally preserved fossil animals, giving palaeontologists a unique window into the evolution of mammals 47 million years ago. A team led by the University of Tübingen and the Martin Luther University Halle-Wittenberg (MLU) has shown that the body size of two species of mammals developed in opposite directions. The study was published in "Scientific Reports".

47 million years ago - the middle Eocene - the Earth was much warmer and the area of Geiseltal was a swampy subtropical forest whose inhabitants included ancestors of the horse, ancient tapirs, large terrestrial crocodiles, as well as giant tortoises, lizards and ground-dwelling birds. So rich are the Geiseltal finds that they give researchers an unprecedented high-resolution picture of evolutionary dynamics at the population level.

A team led by Dr Márton Rabi from the University of Tübingen and the Martin Luther University Halle-Wittenberg (MLU) has shown that the body size of two species of mammals developed in opposite directions. The study, published in Scientific Reports, was carried out with Simon Ring and Professor Hervé Bocherens at the Senckenberg Centre for Human Evolution and Palaeoenvironment and the University of Tübingen in cooperation with Dr Oliver Wings from the MLU.

"We were initially interested in the evolution of the ancient horses, which were about the size of a Labrador dog. These animals are particularly abundant in the Geiseltal fossil record," Rabi says. Researchers initially believed they had several species of early horse. "However, we found that here, there was only one species, whose body size shrank significantly with time," Rabi explains. The team wanted to test whether this body size shift was climate-induced, since past global warming caused body-size reduction in ancient mammals.

Carbon and oxygen isotope studies on fossil teeth provided the scientists with information about the local middle Eocene climate. "They indicate a humid tropical climate. However, we didn't find any evidence for climatic changes in Geiseltal over the period investigated," says Bocherens. To further test the data, the team sought to discover whether the dwarfing process was unique to the horses. For comparison, they examined the evolution of the tapir ancestor called Lophiodon. "We had reason to question the Geiseltal's constant-climate data; so we expected that other mammals would show the same body-size trends as the horses," Simon Ring explains. In a surprising result, the tapirs - also a single species - revealed the opposite trend. They grew larger instead of shrinking. While the ancestors of the horse shrank from an average body weight of 39 kilograms to around 26 kilograms over about a million years, the tapirs increased from 124 kilograms to an average body weight of 223 kilograms.

Differing survival strategies

"All the data indicate that the body size of the horses and tapirs developed differently not because of the climate, but because of different life cycles," explains Bocherens. Small animals reproduce faster and die younger: Relative to their size, they don't have to eat as much to maintain their body mass and can devote more resources to having young. Larger animals live longer and have lower reproduction rates. They have to eat more and therefore have fewer resources for reproduction - but, being large, face fewer predators and can range further to get better food. That extends their lives and gives them more time to breed. The Geiseltal tapirs and the horses therefore likely maximized the different advantages of their respective life cycle strategies, which caused divergent body size evolution.

Exceptional fossil deposits

The Geiseltal fossil site is located in the eastern state of Saxony-Anhalt. In the course of open-cast brown coal mining between 1933 and 1993, tens of thousands of fossil specimens of more than one hundred species were discovered there. Many were the ancestors of modern vertebrates. "The Geiseltal is as important a fossil site as the Messel Pit near Darmstadt, which is a UNESCO World Heritage Site," says Dr. Rabi. "But because the Geiseltal collection was hardly accessible during East German times, it kind of went off the radar."

With 3,000 known species and thousands more left to describe, the wasps of the subfamily Microgastrinae are the single most important group of parasitoids attacking the larvae of butterflies and moths, many of which are economically important pests. Consequently, these wasps have a significant impact on both the world's economy and biodiversity.

Due to their affinities, these wasps are widely used in biological control programs to manage agricultural and forestry pests around the globe. Further, they have also been prominently featured in many basic and applied scientific research (e.g. chemical ecology, biodiversity studies, conservation biology, genomics, behavioural ecology). However, the information about Microgastrinae species is scattered across hundreds of papers, some of which are difficult to find. To make matters worse, there has never been an authoritative checklist of the group at a planetary scale.

All currently available information about the group is now brought together in a large monograph of 1,089 pages, published in the open-access, peer-reviewed journal ZooKeys. The publication presents a total of 2,999 valid extant species belonging to 82 genera. On top of that, the monograph features fossil species and genera, unavailable names and the institutions that store the primary types of all listed species.

Moreover, the researchers have included extensive colour illustrations of all genera and many species (thousands of images in 250 image plates); brief characterisation and diagnosis of all genera; detailed species distributions (within biogeographical regions and per individual country); synopsis of what is known on host-parasitoid associations; summary of available DNA barcodes; estimations of the group diversity at world and regional levels; as well as notes on individual species upon request.

"Compiling this annotated checklist was, more than anything, a labour of love," says Dr. Jose Fernandez-Triana of the Canadian National Collection of Insects, lead author of the paper.

"For the past six or seven years, we have spent thousands of hours pouring through hundreds of publications, reading original descriptions in old manuscripts, checking type specimens in many collections worldwide, exchanging information with colleagues from all continents. For the past year or so, I basically stopped all other ongoing research projects I was involved with, to focus solely (almost obsessively!) on finishing this manuscript. The work was often tedious and mind-numbing, and many times I had the temptation to delay the completion of the paper for a later time. However, I was lucky that the other co-authors were just as passionate as myself, and we all pushed each other to finish the task when energy ran low," comments Dr. Fernandez-Triana.

"For the past few years, the Microgastrinae wasps have been one of the most intensively studied groups of insects, at least from a taxonomic perspective," he adds. "Just to give you an idea: between 2014 and 2019 a total of 720 new species of Microgastrinae were described worldwide. That is an average of one new species every three days, sustained over a six-year period and showing no signs of slowing down."

He also points out that many scientists from many different countries and biogeographical regions have been involved in the description of the new species. The paper recognises them all and their contributions in the Acknowledgements section.

"You could even say that we are witnessing a renaissance in the study of this group of wasps. However, even then, what has been done is only the tip of the iceberg, as we estimated that only 5 to 10% of all Microgastrinae species have been described. That means that we do not have a name, let alone detailed knowledge, for 90-95% of the remaining species out there. Perhaps, there could be up to 50,000 Microgastrinae wasp species worldwide. It is truly humbling when you consider the magnitude of the work that lies ahead."

Yet, it is not only a matter of counting huge numbers of species. More importantly, many of those species either have already been put in use as biocontrol agents against a wide range of agricultural and forestry pests, or have the potential to be in the future.

For applied scientists, working with hyperdiverse and poorly known groups such as Microgastrinae is even more perplexing. Navigating the maze of old names, synonyms (species described more than one time under different names), homonyms (same names applied to different species), or unavailable names (names that do not conform to the rules of the International Commission of Zoological Nomenclature) is a daunting task. Often, that results in the same species being referred to in several different ways by different authors and academic works. Consequently, many historical references are full of misleading or even plainly wrong information. Meanwhile, it is very difficult to seek out the useful and correct information.

The present annotated checklist could work as a basic reference for anyone working with or interested in the parasitoid wasps of the subfamily Microgastrinae. In the future, the authors hope to produce revised editions, thus continuing to incorporate new information as it is generated, and to also correct possible mistakes.

"We welcome all kinds of criticisms and suggestions," concludes Dr. Fernandez-Triana. "And we hope that biocontrol practitioners will also help us, the taxonomists, to improve future versions of this work. However, for the time being, let me say that it is a tremendous relief to get this first version out!"

DURHAM, N.C. -- A professor at Duke University says that the way spilled milk spreads across the floor can explain why economic downturns regularly occur.

In a paper published online on March 5 in the International Journal of Energy Research, Adrian Bejan, the J.A. Jones Distinguished Professor of Mechanical Engineering at Duke, posits that recessions emerge as a natural feature of physics, rooted in the time-dependent movement of spreading over an area.

"This theory sheds light on common questions such as whether or not history repeats itself or if the economy is stable or not," said Bejan. "These are questions that can find answers from physics. There exist universal mechanisms that give rise to laws governing the growth of economics. And the answer to sustaining that growth lies in innovation."

Bejan's conclusion combines the ideas behind two previous papers detailing the prevalence of S-curves in all corners of life and the direct link between economics and fuel consumption.

In 2011, Bejan predicted that the growth of innumerable spreading phenomena over time follows the shape of an "S curve" otherwise known as the sigmoid function, and that this phenomena is a result of the constructal law that he penned in 1996. For example, a bottle of milk spilled on the floor will have a small initial footprint, followed by a rapid finger-shaped expansion across the kitchen's tiles, followed by a final phase of slow creep. This same history of slow, fast, slow can be seen in chemical reactions, population growth, the adoption of new technology and even the spreading of new ideas.

Several years later, Bejan tied together economics and physics, showing that physics accounts for the proportionality between a nation's gross domestic product and its annual consumption of fuel. "Pushing requires power, and power requires fuel, whether it is food that powers the human body or gasoline that powers cars," said Bejan. "And the amount of fuel consumed by a nation is directly related to its economic growth. So really, physics and economics are two sides of the same coin."

In his new work, Bejan replaces the concepts of power with the concepts of economics including money, savings, time and bubbles. He shows that, given the ability to produce excess power and lend it to others as money, the flow of money being spent to push things around a given area looks exactly like the flow of power being used for the same purpose.

"The ability to save and lend, for money to flow between neighbors across the globe, is a chain reaction," said Bejan. "Thus economic development as a whole is a chain reaction, and the physics of that phenomenon is detailed in this paper."

Putting the two concepts together, Bejan shows that the "S" curve of the economic productivity of a commodity clashes with the linear curve of investment. At first, the S curve is below the line, and the investment is a speculative ray of hope. After time, the S curve moves above the investment line and generates prosperity and promise. But as the adoption or usefulness of that commodity, idea or invention wanes, the S curve reaches its plateau and it inevitably crosses back to the wrong side of the investment line.

This is when economic downturns strike. But while Bejan says this event is inevitable for anything and everything that is bought and sold, it doesn't mean that the entire economy has to take a nosedive.

"Everything that spreads has a finite life, and if you don't do something to postpone that precipice, then you will fall over the cliff," said Bejan. "But a market that is free is capable of generating new S curves on top of new S curves. So as long as people are being innovative and creative and bringing large enough new S curves to the picture, the general trend of economic growth can continue."

Since the discovery of penicillin in 1928 by Sir Alexander Fleming, antibiotics have saved millions of lives from fatal infections world-wide. However, with time bacteria have developed mechanisms to escape the effects of antibiotics - they have become resistant.

With fewer antibiotics available to treat resistant bacterial infections, the possibility of entering a pre-antibiotic era is looming ahead.

Alternative strategies are being explored and helper compounds are attracting attention. Helper compounds are non-antibiotic compounds with the capability of enhancing the efficacy of antibiotics.

How to boost antibiotics

One such helper compound has been suspected to be cannabidiol (CBD); a cannabinoid from the cannabis plant. Now a research team from University of Southern Denmark, has published a scientific study proving the effect of CBD.

Janne Kudsk Klitgaard is Principal Investigator and corresponding author. First author is PhD student Claes Søndergaard Wassmann. The study is published in the journal Scientific Reports.

When we combined CBD and antibiotics, we saw a more powerful effect than when treating with antibiotics alone. So, in order to kill a certain number of bacteria, we needed less antibiotics, they say.

Bacteria clones spread globally

In the study, CBD was used to enhance the effect of the antibiotic bacitracin against Staphylococcus aureus bacteria; a major human pathogen that frequently causes community- and hospital-acquired disease.

Multidrug-resistant clones of this pathogen have spread globally. In some countries, treatment of bacterial infections with these resistant bacteria are difficult and the problem is projected to be an ever-larger problem in the future.

According to the researchers, the combination of CBD and antibiotics may be a novel treatment of infections with antibiotic resistant bacteria.

How do the bacteria die?

Three things happened with the Staphylococcus aureus bacteria, when the researchers treated them with the combination in their study:

The bacteria could no longer divide normally.

The expression of certain key genes (cell division and autolysis genes) in the bacteria was lowered.

The bacterial membrane became unstable.

Anti-resistance must be stopped

According to the researchers, overuse of antibiotics is the main cause of antibiotic resistance.

If we combine an antibiotic with a helper compound, that enhances the effect of the antibiotic, we need less antibiotic to achieve the same effect. This may contribute to the development of fewer resistant bacteria, says Janne Kudsk Klitgaard.

An international team of scientists studying lifespans of wild mammals have found that, just like humans, females tend to live significantly longer than their male counterparts.

The researchers looked at the lifespans of 101 different species, from sheep to elephants, and found that females lived an average of 18% longer than males for more than 60% of the species studies. In humans, females tend to live around 7.8% longer.

The study, led by scientists at University Lyon 1 and published in the prestigious journal, Proceedings of the National Academy of Sciences, found this was not due to the sexes aging at different rates but that females had an average lower risk of mortality in adulthood than males.

It was unclear from the data as to why females survive longer than males, however the authors suggest that it could be due to complex interactions between the local environmental conditions and sex-specific costs of reproduction.

Professor Tamás Székely, from the Milner Centre for Evolution at the University of Bath, was one of the authors of the study. He said: 'We've known for a long time that women generally live longer than men, but were surprised to find that the differences in lifespan between the sexes was even more pronounced in wild mammals than in humans.

"This could be either because females are naturally able to live longer, or that female mortality drops compared with males.

"For example, lionesses live at least 50% longer in the wild than male lions. We previously thought this was mostly due to sexual selection - because males fight with each other to overtake a pride and thus have access to females, however our data do not support this. Therefore there must be other, more complex factors at play.

"Female lions live together in a pride, where sisters, mothers and daughters hunt together and look after each other, whereas adult male lions often live alone or with their brother and therefore don't have the same support network.

"Another possible explanation for the sex difference is that female survival increases when males provide some or all of the parental care. This is also true in birds. Giving birth and caring for young becomes a significant health cost for females and so this cost is reduced if both parents work together to bring up their offspring."

The researchers plan to compare the data on wild animals with that of captive zoo animals, which do not have to deal with predators or competition for food or mates. This will allow them to measure the extent to which biological differences between the sexes have an effect on life expectancy.

"By affecting males and females differently, harsh environmental conditions such as a high prevalence in pathogens, is likely to cause sex-differences in lifespan.

"Comparing the sex gap in lifespan and aging across several populations of the same species is definitely full of promises," said Jean-François Lemaître from the National Centre for Scientific Research (University Lyon 1, France) and coordinator of this study.

Nearly all older Americans support adding a dental benefit to the Medicare program that covers most people over age 65, according to a new national poll that also reveals how often costs get in the way of oral health for older adults.

Ninety-three percent of people between the ages of 65 and 80 favor including dental coverage in traditional Medicare, though the percentage dropped to 59% when they were asked if they'd favor it even if they had to pay more for their Medicare benefits.

Just over half of the older adults polled (53%) said they currently have dental coverage. Half of this group are covered as employees or retirees, or spouses of employees.

Another quarter said they have dental coverage because they've chosen to get their Medicare coverage through a Medicare Advantage plan offered by a commercial insurance company. In fact, 72% of those with Medicare Advantage coverage said they'd chosen their plan in part because it covered dental care.

Whether they had insurance or not, cost plays a role in dental decisions, the poll finds. One in five of the older adults polled said they had delayed getting dental care, or gone without it, in the past two years.

The majority of these respondents said cost, or insurance problems, played a role in this decision. Those without dental insurance, and those with lower incomes, were more likely to say they'd delayed or gone without oral care.

The new results come from the National Poll on Healthy Aging, carried out by the University of Michigan Institute for Healthcare Policy and Innovation with support from AARP and Michigan Medicine, U-M's academic medical center. It involved a national sample of more than 1,030 adults aged 65 to 80 who answered a range of questions about their own oral health and dental health policy.

"These results suggest that health care providers and policymakers should seek solutions to better identify and address how cost and other factors act as barriers to dental care among older adults," says Domenica Sweier, Ph.D., D.D.S.

Sweier, a clinical associate professor at the U-M School of Dentistry, helped develop the poll questions and analyze the results. She adds that as providers and policy makers continue to seek solutions, "This will be important to preventing health and social consequences of unmet oral health needs in this population."

Differences across the over-50 age range

A previous National Poll on Healthy Aging report looked at dental health, including insurance and cost factors, among people in their 50s and early 60s. Only one in four of those polled said they lacked dental insurance, but half said they did not know how they would get dental coverage after they retired and some assumed that traditional Medicare would cover their dental care needs.

"Across the spectrum of ages, dental care and coverage vary, and cost plays a major role," says Preeti Malani, M.D., director of the poll and a professor of internal medicine at U-M with special training in the care of older adults. "We know that poor oral health can affect everything from social interactions to eligibility for surgery, so it's important for health professionals as well as policymakers to understand what older adults are experiencing."

One in four of the adults over 65 polled (27%) said they were embarassed by the condition of the teeth, and about the same percentage rated their overall dental health as fair or poor.

The role of dental care costs

One in three hadn't been to the dentist for preventive care such as a cleaning in at least a year. When the research team cross-referenced this with household income, they found that those with incomes over $60,000 were nearly twice as likely as those with incomes less than $30,000 to have gone to the dentist in the past year.

Nearly half of the poll sample (46%) said they were missing teeth but didn't have a denture or implant to fill the gap.

"Coverage of dental care, as well as vision and hearing care, is critical for the long-term health of our population" says Alison Bryant, Ph.D., senior vice president of research for AARP. "Even simple teeth cleanings may not be affordable to seniors living on fixed incomes, so having coverage for dental benefits may help address that problem."

The poll also shines additional light on the growing body of evidence linking oral health and overall health and wellbeing.

Those who said their overall physical or mental health were fair or poor also visited the dentist's office less often, and were more likely to say their oral health was poor. Problems with dry mouth related to medication use, and challenges eating a healthy diet because of untreated dental problems, could make these issue worse, says Malani.

The National Poll on Healthy Aging results are based on responses from a nationally representative sample of 1,039 adults aged 65 to 80 who answered a wide range of questions online. Questions were written, and data interpreted and compiled, by the IHPI team. Laptops and Internet access were provided to poll respondents who did not already have them.

In recent years, the development of CRISPR technologies and gene-editing scissors in particular have taken the world by storm. Indeed, scientists have learned how to harness these clever natural systems in the biotech and pharmaceutical industries, among other areas.

New research from the University of Copenhagen shows that we are not the first to find a way to exploit the benefits of the CRISPR technique. Apparently, primitive bacterial parasites have been doing so for millions of years.

The researchers studied the least described and most enigmatic of the six CRISPR-Cas systems found in nature -- Type IV CRISPR-Cas. Here, they uncovered characteristics that differ entirely from those in other systems.

Redefining CRISPR

"Until recently, CRISPR-Cas was believed to be a defense system used by bacteria to protect themselves against invading parasites such as viruses, much like our very own immune system protects us. However, it appears that CRISPR is a tool that can be used for different purposes by diverse biological entities," according to 28-year-old Rafael Pinilla-Redondo, a PhD at UCPH's Department of Biology who led the research.

One of these biological entities are plasmids - small DNA molecules that often behave like parasites and, like viruses, require a host bacterium to survive.

"Here we found evidence that certain plasmids use type IV CRISPR-Cas systems to fight other plasmids competing over the same bacterial host. This is remarkable because, in doing so, plasmids have managed to turn the system around. Instead of protecting bacteria from their parasites, CRISPR is exploited to perform another task," says Pinilla-Redondo, adding:

"This is similar to how some birds compete for the best nesting site in a tree, or how hermit crabs fight for ownership of a shell."

"A humbling realization"

The discovery challenges the notion that CRISPR-Cas systems have only one purpose in nature, that is, acting as immune systems in bacteria. According to Rafael Pinilla-Redondo, the discovery gives some additional perspective:

"We humans have only recently begun to exploit nature's CRISPR-Cas systems, but as it turns out, we are not the first. These 'primitive parasites' have been using them for millions of years, long before humans. It is quite a humbling realization"

What can we use it for?

The researchers speculate that these systems could be used to combat one of the greatest threats to humanity: multi-drug resistant bacteria. Hundreds of thousands of people die from MDR bacteria every year.

Bacteria become resistant to antibiotics by acquiring genes that make them resistant to antibiotic treatment. Very frequently, this occurs when plasmids transport antibiotic resistant genes from one bacterium to another.

"As this system appears to have evolved to specifically attack plasmids, it is plausible that we could repurpose it to fight plasmids carrying antibiotic resistant genes. This could be achieved because it is possible to program CRISPR to target what one wants" says Pinilla-Redondo.

Researchers from the University of Nebraska, University of Missouri, and Case Western Reserve University published a new paper in the Journal of Marketing that analyzes B2B e-negotiation communications in order to provide sellers with insights into buyers' behavioral responses to salespersons' communications.

The study, forthcoming in the March issue of the Journal of Marketing, is titled "B2B E-Negotiations and Influence Tactics" and is authored by Sunil Singh, Detelina Marinova, and Jagdip Singh.

Advances in digital technologies motivate firms to adopt technology-mediated channels for business interactions. According to reports, 77% of customers prefer e-communications over other formats. For B2B selling, this trend manifests in a 75% increase in e-negotiations and, by one estimate, 80% of U.S. sales negotiations are conducted online. Despite this increase in B2B e-negotiations, little is known about its effectiveness. Compared to face-to-face (F2F) communications, e-communications offer fewer contextual cues and less interactivity and flexibility, but they benefit from easy accessibility, transparency, and ability to deliver diverse materials via attachments and links.

A new study in the Journal of Marketing analyzes e-communications to provide sellers with greater insights about buyers' needs and behaviors. The research team worked with a B2B firm to collect e-negotiation communication data for more than 40 e-negotiations over a two year-period. Using these data, they identified influence tactics, such as textual cues, used by salespeople in day-to-day interactions with buyers during the e-negotiation sales process. Specifically, they identified information sharing, recommendation, promise, and assertiveness as four distinct influence tactics. The research also analyzed buyers' emails to develop a corpus of textual cues that reflect buyers' attention, which is the degree to which a buyer displays behavioral responses to a salesperson's e-communications.

This research revealed that after accounting for known salesperson and customer factors, buyer attention is positively associated with contract award. Furthermore, no individual influence tactic is sufficient to hold a buyer's attention or win the contract award. Effective use of influence tactics requires the concurrent use of complementary tactics that prompt either internalization (internal analyzing) or compliance (risk-shifting) but not both. Information sharing and recommendation work by persuading the receiver to focus on the merit of the argument (internal-analyzing). On the contrary, promise and assertiveness work by obtaining the compliance of the receiver without attempting to persuade the receiver of the appropriateness of the decision. Thus, promise and assertiveness are known to mitigate decision risk, simplify information processing, and/or reduce uncertainty (risk-shifting). If the salesperson uses any other combination of influence tactics (referred to as competitive combination), such as information sharing used with promise or assertiveness or recommendation used with promise or assertiveness, buyer attention decreases.

These results hold several important implications for salespeople and those who manage them. First, the study recommends that sales organizations incorporate into their training programs guidelines that build buyer attention during sales e-negotiations. A 30% increase in buyer attention increases the likelihood of a contract award seven-fold. Sales managers should specify buyer attention as a key process metric. By measuring buyer attention for each e-negotiation on an ongoing basis, the manager can establish a new performance indicator and identify skill gaps that require more directed coaching.

Second, by isolating the benefits of using complementary (internal-analyzing or risk-shifting) influence tactics together, this research suggests a different path to winning contracts. For instance, the concurrent use of assertiveness and promise tactics evoke compliance during e-negotiations and boost buyer attention by 14% on average. Likewise, the concurrent use of information sharing and recommendation tactics evokes internalization during e-negotiations and results in a 15% increase in buyer attention. On the other hand, competitive combinations that are concurrently deployed invite losses in buyer attention (30% on average) and significantly diminish the likelihood of contract award.

A research team consisting of Ryota Kondo (Ph.D. candidate), Yamato Tani (Graduate student), and Professor Michiteru Kitazaki from Toyohashi University of Technology; Associate Professor Maki Sugimoto from Keio University; and Professor Masahiko Inami from The University of Tokyo investigated the difference between the sense of ownership of the whole body and the sense of ownership of body parts using scrambled body stimulation. Only the observer's hands and feet were presented, and their spatial arrangement was randomized. It was found that observing the scrambled body stimulus while moving the whole body produces a sense of possession of the body part with respect to the hands and feet, but cannot sense possession of the whole body. This result suggests that spatial arrangement is important for the illusion of whole-body ownership. In addition, a person's bodily self-consciousness may be affected by the spatial arrangement of one's own body. The results of this study were published in the open access journal Scientific Reports in 24th March 2020.

Whole body ownership is an important phenomenon to examine bodily self-consciousness. However, differences between ownership in body parts and ownership in the whole body are not completely understood as there is no effective method to separate these senses of ownership.

Therefore, the research team aimed to develop a method to separate the ownership of body parts from the ownership of whole body. Based on their previous study (Kondo et al., Scientific Reports, 2018) on transparent body stimulation, a scrambled body stimulation that randomly rearranges the positions of hands and feet was conducted. Then, in order to compare it with the stimulus of the same arrangement as the normal body, synchronization with the physical movement was controlled.

In Experiment 1, 16 volunteers observed limb-only stimuli from a third-person perspective (2 m behind the stimuli) on a head-mounted display. As a result, when vision and physical movement were synchronized, scrambled body stimulation produced only body part ownership (It felt as if the virtual limbs were of their body), whereas normal placement body stimulation produced both body part ownership and whole body ownership (it felt as if the space between the limbs was their body). Similar results were obtained in Experiment 2, in which 16 participants observed the stimulus from a first-person perspective. Thus, humans can have ownership of body parts even if the body parts are scrambled, but cannot have the whole-body ownership. However, there was no significant difference in any of the skin conductance response measurement experiments for threat stimuli in Experiment 3, conducted on 20 participants.

These results suggest that a spatial placement is necessary for whole-body ownership, but not necessarily for body-part ownership. Therefore, a person's bodily self-consciousness might be restricted by the spatial arrangement of normal body parts. However, the limitation of this study was that there was no difference in skin conductance (physiological) response to a threat stimulus.

Scrambled body stimulation provides a method to systematically examine the sense of ownership of the whole body and body parts. Moreover, it helps explore the limitations of the illusion of how much we can change our body scheme while retaining whole-body ownership.