Culture

The balance between weight gain and weight gain loss is predominantly determined by what you eat, how much you eat, and by how much exercise you get. But another important factor is often neglected... Published February 27 in the open-access journal PLOS Biology, research conducted by Kevin Kelly, Owen McGuinness, Carl Johnson and colleagues of Vanderbilt University, USA shows that it's not just how many calories you eat, but WHEN you eat them that will determine how well you burn those calories.

Your daily biological clock and sleep regulate how the food you eat is metabolized; thus the choice of burning fats or carbohydrates changes depending on the time of day or night. Your body's circadian rhythm has programmed your body to burn fat when you sleep, so when you skip breakfast and then snack at night you delay burning the fat.

The researchers monitored the metabolism of mid-aged and older subjects in a whole-room respiratory chamber over two separate 56-hour sessions, using a "random crossover" experimental design. In each session, lunch and dinner were presented at the same times (12:30 and 17:45, respectively), but the timing of the third meal differed between the two halves of the study. Thus in one of the 56-hour bouts, the additional daily meal was presented as breakfast (8:00) whereas in the other session, a nutritionally equivalent meal was presented to the same subjects as a late-evening snack (22:00). The duration of the overnight fast was the same for both sessions.

Whereas the two sessions did not differ in the amount or type of food eaten or in the subjects' activity levels, the daily timing of nutrient availability, coupled with clock/sleep control of metabolism, flipped a switch in the subjects' fat/carbohydrate preference such that the late-evening snack session resulted in less fat burned when compared to the breakfast session. The timing of meals during the day/night cycle therefore affects the extent to which ingested food is used versus stored.

This study has important implications for eating habits, suggesting that a daily fast between the evening meal and breakfast will optimize weight management.

Like many poisonous animals, the African monarch butterfly's orange, white and black pattern warns predators that it is toxic. Warning patterns like this are usually consistent across individuals to help predators learn to avoid them. However, a recent study, published February 27 in the open-access journal PLOS Biology, shows how a population of African monarch butterflies (Danaus chrysippus) breaks this rule and has highly variable warning patterns. The study, by Simon Martin of the University of Edinburgh, UK and colleagues shows that the unlikely answer lies in the interaction with a bacterium that specifically kills male butterflies.

Previous research had shown that all female butterflies in this East African population have two unusual features: Firstly, they have a new arrangement of their chromosomes where the chromosome containing genes that control color patterns is fused to their one of their sex chromosomes (called the W chromosome). This new chromosome is called the neo-W. Secondly, they are all infected with a bacterium called Spiroplasma that kills all of their sons. What was not clear, however, was whether these two features were linked, and whether they could explain the highly variable color patterns that changed from season to season.

To answer this, the researchers analyzed the entire DNA sequence of the bacteria and the female butterflies' chromosomes. This showed that the neo-W chromosome alters color patterns and has spread rapidly through the population, aided by the male-killing bacteria. However, because the bacterium only allows female offspring, it promotes the survival of one particular color pattern gene that is always passed from mother to daughter. This left one puzzle for the scientists still to solve - if the females all carried the same color gene, then why was the East African population so variable?

The study found that this female color gene has only a weak effect that is overridden by color genes from the father. Therefore, fathers with different patterns will produce daughters with different patterns. Seasonal fluctuations in wind patterns are thought to affect which subspecies of male immigrants end up in this region, leading to seasonal changes in female color patterns. Even though they always resemble their father, the infected hybrid daughters, unable to produce sons, represent a genetic dead-end for fathers, whose color pattern genes only survive for one generation before being wiped out.

Dr. Simon Martin said, "The relatively fast emergence and spread of a new chromosome, combined with the short life cycle of the butterfly, allows us to study how the microbe is altering the evolution of the butterfly, almost in real-time. We are continually discovering new ways in which microbes manipulate their hosts, and male-killing is just one example of this. It makes you wonder to what extent the evolution of other organisms - even humans - is affected by such unseen forces."

New research suggests that companies looking to promote their latest environmentally friendly product should downplay its green credentials if they want consumers to buy it.

By highlighting green attributes through advertising, in some situations firms risk generating associations with weak product performance, say researchers from the University of East Anglia (UEA) and University of Leeds. This is because of the performance ability sometimes associated with green products, whereby consumers perceive them as being less effective.

Instead, by downplaying the product's greenness firms may be more likely to persuade consumers to buy it, if it is promoted on more traditional, rather than performance, aspects.

Green products usually include environmentally friendly features that are less harmful to the planet and population, such as biodegradable and nontoxic ingredients, that enhance energy efficiency and include recycled components.

However, while it has been suggested that consumers are willing to buy such products, these attitudes rarely result in purchases and they often buy the conventional alternatives.

Previous research has found that consumers tend to choose products with superior functional performance over products with superior sustainability characteristics, and indicates that this choice is often related to assumptions about the performance ability of green products.

This new study, led by Dr Bryan Ursey of UEA's Norwich Business School, shows that the product category can influence the effect of a green product advertising strategy on performance assessments, and that subtle, or 'implicit' messaging is more effective in conditions under which consumers have more concerns about the product's performance or have lower expectations about its greenness.

Published in the Journal of Advertising, the findings suggest that when product-related attributes are prominent, or 'explicit', in advertising, if consumers perceive them as being at odds with the benefits associated with the product category, the resulting incompatibility will further reduce their performance evaluations.

Dr Ursey, a lecturer in marketing, said: "Given consumers' perceptions of poorly performing green products, persuading them to alter their consumption habits remains a difficult task for marketers.

"While firms have often attempted to enhance their environmental credentials by emphasizing a new product's green attributes, we show that this may in fact have negative consequences.

"Our findings show that it would be sensible to match the advertisement and its information to the product being marketed, in terms of both its associated category and the optionality of the attribute. In addition, as green products are often associated with poorer performance, firms would do well to tailor their advertising to meet the expected benefits associated with a given product category."

The most prominent advertising strategy used by firms includes products' environmental characteristics. For example, car manufacturer Toyota makes the Prius's low emissions and fuel consumption prominent, clearly stating that the product has environmental benefits. By contrast, Tesla and BMW reduce the prominence of such information, focusing instead on products' performance-related characteristics, such as, acceleration time, handling ability.

These examples represent two distinct advertising strategies - namely, green emphasis and understatement. The former aims to make products' green characteristics clear, employing what the researchers term as 'explicit signals'. The latter strategy reduces this prominence; the 'implicit signals' approach.

The researchers examined whether, why, and when an implicit (green understatement) versus explicit (green emphasis) advertising strategy leads to higher performance evaluation for green products.

They conducted two experiments, one with an advertisement for a new laundry detergent and the other using an advert for a washing machine that featured a new eco-mode, which reduces power and water usage.

They found that implicit, rather than explicit, communication about greenness leads to higher performance evaluations and purchase intent for products that are less commonly green (the detergent) and for products that have an optional green mode (the washing machine).

The authors says the findings have important implications for public policy makers and support the notion that consumers are more likely to engage in prosocial actions when the request for help is accompanied by some form of personal benefit. In the area of energy conservation, for example, a benefit appeal might emphasize money savings to the homeowner or, in the case of this research, highlight performance aspects.

"When encouraging consumers to act in a more sustainable manner, downplaying the environmental aspects of the behavior may further increase evaluations and intent to buy," said Dr Ursey. "Our results also suggest that optionality could play a role in determining green behaviour. Informing consumers about and providing them with reasonable options may do more to encourage green behaviour, as they would be acting out of their own volition, rather than being forced to."

Leesburg, VA, February 28, 2020--Although the imaging features of novel coronavirus disease 2019 (COVID-19) are variable and nonspecific, the findings reported thus far do show "significant overlap" with those of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), according to an ahead-of-print article in the American Journal of Roentgenology (AJR).

COVID-19 is diagnosed on the presence of pneumonia symptoms (e.g., dry cough, fatigue, myalgia, fever, dyspnea), as well as recent travel to China or known exposure, and chest imaging plays a vital role in both assessment of disease extent and follow-up.

As per her review of the present clinical literature concerning COVID-19, Melina Hosseiny of the University of California at Los Angeles concluded: "Early evidence suggests that initial chest imaging will show abnormality in at least 85% of patients, with 75% of patients having bilateral lung involvement initially that most often manifests as subpleural and peripheral areas of ground-glass opacity and consolidation."

Furthermore, "older age and progressive consolidation" may imply an overall poorer prognosis.

Unlike SARS and MERS--where initial chest imaging abnormalities are more frequently unilateral--COVID-19 is more likely to involve both lungs on initial imaging.

"To our knowledge," Hosseiny et al. continued, "pleural effusion, cavitation, pulmonary nodules, and lymphadenopathy have not been reported in patients with COVID-19."

Ultimately, the authors of this AJR article recommended CT for follow-up in patients recovering from COVID-19 to evaluate long-term or even permanent pulmonary damage, including fibrosis--as seen in SARS and MERS infections.

WHAT:
The emergence and rapid increase in cases of coronavirus disease 2019 (COVID-19), a respiratory illness caused by a novel coronavirus, pose complex challenges to the global public health, research and medical communities, write federal scientists from NIH's National Institute of Allergy and Infectious Diseases (NIAID) and from the Centers for Disease Control and Prevention (CDC). Their commentary appears in The New England Journal of Medicine.

NIAID Director Anthony S. Fauci, M.D., NIAID Deputy Director for Clinical Research and Special Projects H. Clifford Lane, M.D., and CDC Director Robert R. Redfield, M.D., shared their observations in the context of a recently published report on the early transmission dynamics of COVID-19. The report provided detailed clinical and epidemiological information about the first 425 cases to arise in Wuhan, Hubei Province, China.

In response to the outbreak, the United States and other countries instituted temporary travel restrictions, which may have slowed the spread of COVID-19 somewhat, the authors note. However, given the apparent efficiency of virus transmission, everyone should be prepared for COVID-19 to gain a foothold throughout the world, including in the United States, they add. If the disease begins to spread in U.S. communities, containment may no longer be a realistic goal and response efforts likely will need to transition to various mitigation strategies, which could include isolating ill people at home, closing schools and encouraging telework, the officials write.

Drs. Fauci, Lane and Redfield point to the many research efforts now underway to address COVID-19. These include numerous vaccine candidates proceeding toward early-stage clinical trials as well as clinical trials already underway to test candidate therapeutics, including an NIAID-sponsored trial of the experimental antiviral drug remdesivir that began enrolling participants on February 21, 2020.

"The COVID-19 outbreak is a stark reminder of the ongoing challenge of emerging and re-emerging infectious pathogens and the need for constant surveillance, prompt diagnosis and robust research to understand the basic biology of new organisms and our susceptibilities to them, as well as to develop effective countermeasures," the authors conclude.

Scientists at the University of Sussex have measured a property of the neutron - a fundamental particle in the universe - more precisely than ever before. Their research is part of an investigation into why there is matter left over in the universe, that is, why all the antimatter created in the Big Bang didn't just cancel out the matter.

The team - which included the Science and Technology Facilities Council's (STFC) Rutherford Appleton Laboratory in the UK, the Paul Scherrer Institute (PSI) in Switzerland, and a number of other institutions - was looking into whether or not the neutron acts like an "electric compass". Neutrons are believed to be slightly asymmetrical in shape, being slightly positive at one end and slightly negative at the other - a bit like the electrical equivalent of a bar magnet. This is the so-called "electric dipole moment" (EDM), and is what the team was looking for.

This is an important piece of the puzzle in the mystery of why matter remains in the Universe, because scientific theories about why there is matter left over also predict that neutrons have the "electric compass" property, to a greater or lesser extent. Measuring it then it helps scientists to get closer to the truth about why matter remains.

The team of physicists found that the neutron has a significantly smaller EDM than predicted by various theories about why matter remains in the universe; this makes these theories less likely to be correct, so they have to be altered, or new theories found. In fact it's been said in the literature that over the years, these EDM measurements, considered as a set, have probably disproved more theories than any other experiment in the history of physics. The results are reported today, Friday 28 February 2020, in the journal Physical Review Letters.

Professor Philip Harris, Head of the School of Mathematical and Physical Sciences and leader of the EDM group at the University of Sussex, said:

"After more than two decades of work by researchers at the University of Sussex and elsewhere, a final result has emerged from an experiment designed to address one of the most profound problems in cosmology for the last fifty years: namely, the question of why the Universe contains so much more matter than antimatter, and, indeed, why it now contains any matter at all. Why didn't the antimatter cancel out all the matter? Why is there any matter left?

"The answer relates to a structural asymmetry that should appear in fundamental particles like neutrons. This is what we've been looking for. We've found that the "electric dipole moment" is smaller than previously believed. This helps us to rule out theories about why there is matter left over - because the theories governing the two things are linked.

"We have set a new international standard for the sensitivity of this experiment. What we're searching for in the neutron - the asymmetry which shows that it is positive at one end and negative at the other - is incredibly tiny. Our experiment was able to measure this in such detail that if the asymmetry could be scaled up to the size of a football, then a football scaled up by the same amount would fill the visible Universe".

The experiment is an upgraded version of apparatus originally designed by researchers at the University of Sussex and the Rutherford Appleton Laboratory (RAL), and which has held the world sensitivity record continuously from 1999 until now.

Dr Maurits van der Grinten, from the neutron EDM group at the Rutherford Appleton Laboratory (RAL), said:

"The experiment combines various state of the art technologies that all need to perform simultaneously. We're pleased that the equipment, technology and expertise developed by scientists from RAL has contributed to the work to push the limit on this important parameter"

Dr Clark Griffith, Lecturer in Physics from the School of Mathematical and Physical Sciences at the University of Sussex, said:

"This experiment brings together techniques from atomic and low energy nuclear physics, including laser-based optical magnetometry and quantum-spin manipulation. By using these multi-disciplinary tools to measure the properties of the neutron extremely precisely, we are able to probe questions relevant to high-energy particle physics and the fundamental nature of the symmetries underlying the universe. "

50,000 measurements

Any electric dipole moment that a neutron may have is tiny, and so is extremely difficult to measure. Previous measurements by other researchers have borne this out. In particular, the team had to go to great lengths to keep the local magnetic field very constant during their latest measurement. For example, every truck that drove by on the road next to the institute disturbed the magnetic field on a scale that would have been significant for the experiment, so this effect had to be compensated for during the measurement.

Also, the number of neutrons observed needed to be large enough to provide a chance to measure the electric dipole moment. The measurements ran over a period of two years. So-called ultracold neutrons, that is, neutrons with a comparatively slow speed, were measured. Every 300 seconds, a bunch of more than 10,000 neutrons was directed to the experiment and examined in detail. The researchers measured a total of 50,000 such bunches.

A new international standard is set

The researchers' latest results supported and enhanced those of their predecessors: a new international standard has been set. The size of the EDM is still too small to measure with the instruments that have been used up until now, so some theories that attempted to explain the excess of matter have become less likely. The mystery therefore remains, for the time being.

The next, more precise, measurement is already being constructed at PSI. The PSI collaboration expects to start their next series of measurements by 2021.

Search for "new physics"

The new result was determined by a group of researchers at 18 institutes and universities in Europe and the USA on the basis of data collected at PSI's ultracold neutron source. The researchers collected measurement data there over a period of two years, evaluated it very carefully in two separate teams, and were then able to obtain a more accurate result than ever before.

The research project is part of the search for "new physics" that would go beyond the so-called Standard Model of Physics, which sets out the properties of all known particles. This is also a major goal of experiments at larger facilities such as the Large Hadron Collider (LHC) at CERN.

The techniques originally developed for the first EDM measurement in the 1950s led to world-changing developments such as atomic clocks and MRI scanners, and to this day it retains its huge and ongoing impact in the field of particle physics.

A new compound has the potential to bind to DNA and activate genes, which could lead to new treatments for cancers and hereditary diseases. Zutao Yu, Ganesh Pandian Namasivayam, and Hiroshi Sugiyama of Kyoto University's Integrated Cell-Material Sciences (iCeMS) collaborated with colleagues in Japan and the USA to design and test a compound that could target specific DNA sequences and recruit gene-modifying molecules. Their findings were published in the journal ChemComm.

Scientists have long worked with small molecules called pyrrole-imidazole polyamides (PIPs) that have the ability to bind to minor grooves found in the DNA helix. They have been experimenting with PIPs as a drug-delivery mode that can switch genes on and off.

One such system involves combining a PIP with a 'host-guest assembly' (HoGu) that can strongly bind to DNA and act similarly to proteins, called transcription factors, that target and bind to specific genes to signal for them to turn on or off.

These PIP-HoGu systems can successfully mimic and disrupt transcription factor pairs from binding to DNA, resulting in a variety of biological effects. But they don't have the ability to specifically activate genes.

Sugiyama and colleagues experimented with the idea of combining a PIP-HoGu system with an epigenetic drug, which can bind to and affect gene activation.

First, they improved the design of PIP-HoGu by selecting molecules that can strongly bind to DNA, while also being non-toxic, cell-permeable, water-soluble, and chemically stable. They then fine-tuned the molecules so that they targeted specific DNA nucleic acid sequences with flexible gap spacings.

The team next attached their new PIP-HoGu system to an epigenetic regulator molecule, forming what they refer to as 'ePIP-HoGu'. They found that it more specifically bound to the targeted nucleic acid sequences and efficiently marked them for epigenetic modification.

"Our ePIP-HoGu is formed of three main components: a DNA-binding PIP, a cooperation domain, and an epigenetic modulator. Fine-tuning each of the three parts led to positive activity. Further optimization is required to explore its full potential and expand its biological and therapeutic applications," says Yu.

This study builds on previous research to help advance PIPs as potential therapeutic drugs to address unmet needs in cancer treatment, rare hereditary diseases and in regenerative medicine, adds Namasivayam.

Biofuel is often touted as a clean fuel, but the fact that it is made using food sources is a major drawback. To address this issue, there has been continuous research on the development of second-generation biofuels using lignocellulosic biomass.

The Korea Institute of Science and Technology (KIST, President Lee Byung-Gwon) recently announces that it has developed an effective biofuel production process through the KIST-UBC (University of British Colombia) lab program in Vancouver, Canada. The process leverages the genetic engineering of *lignin and **bio-derived deep eutectic solvents (DESs)

Lignin makes up 20% to 30% of lignocellulosic biomass but also hinders the production of biofuel, so it is usually separated and discarded or simply burned. The efficient removal of lignin and valorization of lignin are of critical importance to the economic feasibility and commercialization of second-generation biofuels.

A lignin genetic engineering that can separate lignin more effectively was developed by researchers from the ***Joint BioEnergy Institute. Using this new technology, a part of lignin's structure was altered and made shorter, requiring only a small amount of energy or chemicals to remove the lignin.

A bio-derived deep eutectic solvent (DES), developed by Dr. Kwang Ho Kim (PNAS July 9, 2019 116 (28) 13816-13824) was later added to this process. Finally, an analysis technology developed by UBC was used to complete the biofuel production process and ensure the process's economic feasibility.

A wide array of knowledge and skills in biology, analytical chemistry, and chemical engineering were required to develop the technology and its related processes. Over the past several years, many different types of biofuel research have been conducted in several different fields. However, there have been only a few works to connect the different research studies and their resulting technologies. To solve this issue, Dr. Kim Kwang Ho from KIST proposed and carried out joint research with the University of British Columbia in Canada and the State University of New York (College of Environmental Science and Forestry) in the United States. Together, the researchers were able to maximize and combine the potential of several different fields, including genetic engineering, process technology, and analysis technology.

"This research has produced results by maximizing the core competencies of each field represented by the participating Korean, U.S., and Canadian researchers in a bid to address an international agenda--namely, the development of climate change response technology," said Dr. Kim. "We will continue to develop Korea's fundamental technology and tackle climate change and global warming by playing a leading role in the convergence research we are conducting in collaboration with the outstanding research teams based in North America, to develop a sustainable bioenergy production technology."

The study, led by the University of York, found evidence for a period of enhanced pre-industrial sea-level rise of about two to three millimetres per year in three locations: Nova Scotia, Maine and Connecticut.

The researchers say that the large rises at these three locations were natural, and partly related to the North Atlantic Oscillation - a large-scale atmospheric pressure see-saw over the North Atlantic region - and to periods of enhanced ice melt in the Arctic.

The authors of the study say cities like New York and Boston will have to take into account this natural variability in planning for future sea level rise.

The findings are based on sea level reconstructions derived from salt-marsh sediments from the Atlantic coast and from microscopic salt-marsh fossils.

Previous studies have shown that, since the 1950s, rates of sea level rise along the Atlantic coast of North America were faster than the global average - leading to this region coming to be known as a sea level rise "hotspot."

However, lead author Prof Roland Gehrels, from the University of York's Department of Environment and Geography, said this earlier rapid episode of sea level rise in the 18th Century wasn't known before.

"To find out what global warming is doing to sea levels today we need that base level from historical times.

"In the 20th Century we see rates of up to three or four millimetres per year, faster than in any century in at least the last 3000 years.

"In the 18th Century they were slightly slower, but still much quicker than you would expect for the Little Ice Age, partly because the Arctic was relatively warm during the 18th Century.

"It is pre-industrial so there are no anthropogenic forces - or human influences - at play, but in the 20th Century there may well have been.

"This means that those rapid episodes of sea level rise on the north east coast of North America in the 18th Century have a natural cause."

Scientists say salt-marshes are good "archives" of sea levels as they contain several metres of sediment which contains data going back hundreds of years.

Prof Gehrels added: "The high rates in this "hotspot" could present significant coastal risks for large population centres if they are a persistent and recurring feature.

"The likely future sea level rise in places like New York City is expected to be considerably greater than the global average by the end of the 21st century."

"Our findings suggest that enhanced rates of sea level rise along eastern North America are not only symptomatic of human activity, but might additionally arise from natural processes in the climate system."

The findings are published in Geophysical Research Letters and involved collaboration with the University of Leeds; Durham University; Bangor University; the National Oceanography Centre, Liverpool; Woods Hole Oceanographic Institution, Massachusetts, USA; Old Dominion University, Virginia, USA; and the University of Siegen, Germany.

Using microscopic video analysis, a research group from Kumamoto University, Japan has provided deeper insight into the mechanics of plant cell division. The video reveals that the shape of phragmoplasts--cell structures that create the partition between two dividing plant cells--is controlled by actin filaments.

The discovery was made while the researchers were analyzing phragmoplast behavior during cytokinesis: the point in cell division where daughter cells physically separate. They noticed a change in the phragmoplast shape that could only be seen for about 30 seconds in the video. Even though plant cell division mechanisms have been thoroughly studied, the role that actin filaments play in the process appears to have been previously overlooked.

During plant cell division, a partition called a cell plate appears between two chromosomes and expands to divide the cell into two. This cell plate is created by the phragmoplast, which appears only during cell division and contains microtubules and actin filaments. Microtubules were known to play a major role in the formation of the phragmoplast, as destroying them with chemicals results in non-formation of the cell plate. On the other hand, the role of actin filaments was not well understood, since their destruction does not cause any noticeable change in phragmoplasts or cell plates.

Using microscopic video analysis to examine the changes that occur in the phragmoplast and cell plate when actin filaments are disrupted, Dr. Takumi Higaki and graduate student Mr. Keisho Maeda noticed that the phragmoplast became abnormally wide immediately after it was created. (Normal phragmoplasts are constricted toward the center of the cell.) Interestingly, this change was observed for as little as 30 seconds immediately its creation, after which the effects of the disrupted actin filaments became less apparent. Furthermore, the shape of the cell plate changed only when the shape of the phragmoplast changed. These findings indicate that actin filaments are involved in the formation of cell plates through control of new phragmoplast development.

Additionally, the researchers examined the behavior of several proteins thought to be carried by phragmoplasts to cell plates and are responsible for phragmoplast expansion. Some proteins were found to accelerate the timing of transport to the cell plate when actin filaments are disrupted. It is thought that the phragmoplast has two stages, a "childhood" and an "adolescence." Actin filaments are necessary for shaping its childhood, but are not necessary during adolescence. Apparently, cells will eventually divide normally without actin filaments, but it remains to be determined whether the absence of actin filaments does not have an effect on cells after their "adolescence."

"This discovery has shed some light on the role of actin filaments during plant cytokinesis. Actin filaments were found to be present in phragmoplasts about 35 years ago, and a lot of research has been done since then, but there appears to be no report on this phenomenon," said Dr. Higaki. "This is probably because recent time-lapse image analysis technology has improved and is now able to capture subtle differences in a short time; these were very difficult to notice with conventional observation methods. We advocate 'imaging biology' that utilizes image analysis technology in biology, and we hope to keep finding new phenomena with a similar research approach."

Freising/Germany - Researchers at the Leibniz-Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM) have confirmed the presence of the rare amino acid ethionine in a plant - or more precisely, in the fruit of the durian tree. Despite its pungent odor, durian is very popular in Southeast Asia. As the team of scientists has shown, the amino acid plays a key role in the formation of the characteristic durian odor.

The pulp of a ripe durian emits an unusually potent and very persistent smell that is reminiscent of rotten onions. That is why the fruit has been banned on local public transportation in Singapore and at numerous hotels in Thailand. Nevertheless, different varieties of durian are highly valued in many Asian countries. Durian pulp has a high nutritional value, a distinctly sweet taste, and a pleasantly creamy consistency.

Enzyme releases odorant from amino acid

Previous research conducted at the Leibniz-LSB@TUM had already shown that the fruit's stench is essentially due to the odorant ethanethiol and its derivatives. However, the biochemical pathway by which the plant produces ethanethiol remained unclear. As Nadine S. Fischer and Martin Steinhaus of the Leibniz-LSB@TUM have now demonstrated for the first time in their new study, ethionine is the precursor of the foul-smelling substance.

"Our findings suggest that as the fruit ripens, a plant-specific enzyme releases the odorant from ethionine," says lead author Nadine Fischer. "This is consistent with our observation that during fruit ripening not only the ethionine concentration in the pulp increases, but also at the same time that of the ethanethiol. The latter explains why a ripe durian emits an extremely strong smell."

Relevant not only from an olfactory aspect

"Knowing exactly how much ethionine the durian fruit contains is interesting not only because of its significance for the odor," says principle investigator Martin Steinhaus. The food chemist adds that animal tests and cell culture studies have verified that the amino acid is not harmless. Rats that incorporated high doses of the amino acid together with their food developed liver damage and cancer of the liver. A newer study, however, suggests that low concentrations of ethionine may even have positive immunomodulatory effects.

"This raises the question of whether eating the fruit entails health risks," says Steinhaus. "Further studies certainly need to be conducted." The expert reassures us, however, by noting that "in order to consume a comparable dose of ethionine that had toxic effects in animal tests, a person weighing 70 kilograms would in one day have to eat 580 kilograms of fruit pulp of the Krathum variety which is especially rich in ethionine."

A research team has uncovered a genetic signature that enables cells to adapt their protein production according to their state. The researchers of the University of Basel's Biozentrum report in Genome Biology that this newly discovered mechanism plays a role in the regulation of protein production during cell division.

The production of proteins is the most energy-consuming activity of cells. It needs to be tightly regulated, to ensure efficient use of cellular resources. Researchers led by Prof. Mihaela Zavolan at the Biozentrum of the University of Basel have now discovered how the genetic code is used to adjust the protein production depending on the cell growth and division. This mechanism may also be involved in uncontrolled cell division.

Several codons for one amino acid

The genetic code is like a language consisting solely of three letter words, known as 'codons'. Each codon stands for an amino acid, the building blocks of proteins. As there are 64 codons for the 20 amino acids, most amino acids are encoded by more than one codon.

The multiple codons that represent one and the same amino acid are not equally frequent in the genome. Some occur frequently while others are rare. "Previously it was assumed that rare codons generally reduce the rate of protein synthesis," says Zavolan. "Our findings, however, provide a more subtle picture. We could show that rare codons allow the production of specific proteins to be boosted during cell division."

Rare codons regulate protein synthesis

To synthesize a protein, the gene that encodes that protein must first be copied. This copy, called mRNA, is then decoded into a sequence of amino acids by specific molecules in the cell's protein factories. In proliferation-related mRNAs, amino acids tend to be encoded by rare codons, which leads to relatively inefficient protein synthesis when the cells are in resting state. This is because rare codons take longer to be 'read' due to the low availability of decoding molecules.

"The situation changes when the cell switches to division. In this case, more decoding molecules are available to 'read' the rare codons," explains Joao Guimaraes, the first author of the study. "The mRNAs enriched in such codons, which turn out to be important for cell proliferation, are more efficiently translated and thus, experience a boost in protein synthesis." In this way, rare codons help to control the production of a particular class of proteins and to adapt it to the needs of the cell.

Genetic signature for cell proliferation

"Our study challenges the current view that the rare codons are simply detrimental for protein production," says Guimaraes. "We have demonstrated that rare codons are involved in specifically boosting the production of proteins necessary for cell division." The findings on the genetic signature may have implications for understanding the dysregulation of protein synthesis during tumor development, which is caused by uncontrolled cell growth and proliferation.

The spatial arrangement of genetic material within the cell nucleus plays an important role in the development of an organism. A research team from the University of Basel, in collaboration with scientists from Harvard University, has developed a method to trace the chromosomes in individual cells. Using this method, they have now been able to demonstrate that chromosomes reorganize during embryonic development. The study has recently been published in Molecular Cell.

Our body is made up of a wide variety of cells with the most diverse functions. Irrespective of being heart, liver or nerve cells, however, they all contain the same genetic information. The reason why cells develop differently is that only parts of their chromosomes are read. This results in some genes being active while others, in contrast, are silent.

For gene activation, both the way the genes are packaged as well as their spatial organization in the cell nucleus play a decisive role. Prof. Susan Mango's team at the Biozentrum of the University of Basel has now investigated this 3D architecture more closely. Using a novel technique, they were able to trace individual chromosomes during embryonic development in nematodes and show that they rearrange themselves during the early phase.

Chromosome arrangement is not random

If stretched out, all the DNA molecules of a cell would reach about two meters in length. So the DNA must be densely packed to fit into a cell nucleus of only few micrometers in size. The DNA strands are very tightly coiled and twisted to form space-saving structures, called chromosomes. The packaging and the arrangement of the DNA of the chromosomes determines the activity of genes.

In their study, the researchers led by Prof. Susan Mango traced individual chromosomes and investigated their organization during early embryonic development. Embryonic cells of the nematode C. elegans served as a model. "Using a novel technique, we were able to follow the spatial rearrangement of chromosomes in single cells at the beginning of embryogenesis," says Mango. "The advantage of this method is that the cells and tissue remain completely intact."

Early chromosomes resemble a barbell

It is well know that chromosome regions with similar functional properties contact each other and interact. This means that chromosome domains segregated into two compartments, active and inactive. "During early embryogenesis, however, the chromosomes are organized differently," says Ahilya Sawh, first author of the study. "In the early embryo, they are organized into an unconventional barbell-like structure, with inactive compartments separated by a central active region." The researchers discovered that the nuclear lamina - a protein mesh lining the inner surface of the cell nucleus - is required to achieve this barbell arrangement. The lamina is attached to the inactive sections and stretches the chromosome.

Chromosomes reorganize during embryogenesis

"Only at a later stage of embryonic development, when the germ layers develop, we actually see the well-known segregation into an active and inactive region," explains Mango. "Using chromosome tracing, we were able to map the whole 3D chromosome architecture and could show for the first time that chromosomes rearrange during early development, a maturation process that requires the nuclear lamina."

The reorganization of the chromosomes accompanies cell maturation and represents a milestone in the development of a complex organism. The correct chromosomal architecture is crucial to prevent developmental disorders.

A new study in the journal Science has given insight into why the world's oceans are full of more species than ever before - a question that has long been a focus of paleontological research.

The most diverse kinds of animals in the modern oceans, such as fish, mollusks, and crustaceans, diversified slowly and steadily for long periods of time, and were buffered against extinction.

Andrew Bush, an author on the paper and associate professor of Geosciences and Ecology & Evolutionary Biology in the College of Liberal Arts and Sciences, says that knowing how biodiversity evolved over Earth's history can help humans think about future issues with environmental disruptions, like climate change.

"Paleontology can help us identify traits that helped species survive and thrive in the past, including during mass extinctions," Bush says. "Hopefully, research like this can help us plan for the effects of environmental disruption in the coming decades."

The study examined approximately 20,000 genera (groups of related species) of fossil marine animals across the past 500 million years, and approximately 30,000 genera of living marine animals.

The findings clearly show that the species in the most diverse animal groups also tend to be more mobile and more varied in how they feed and live, notes lead study author Matthew Knope, assistant professor of biology at the University of Hawai`i at Hilo.

"Being a member of an ecologically flexible group makes you resistant to extinction, particularly during mass extinctions," he says. "The oceans we see today are filled with a dizzying array of species in groups like fishes, arthropods, and mollusks, not because they had higher origination rates than groups that are less common, but because they had lower extinction rates over very long intervals of time."

The "slow and steady" development of lineages through time has been a key factor in dictating which lineages have achieved the highest diversity.

Michal Kowalewski, professor of invertebrate paleontology at the University of Florida, who was not involved with the study, said the study highlights "the value of paleontological data for assessing core questions of biology."

"Perhaps the fable of the tortoise and the hare is apt in explaining marine animal diversification: some groups jumped out to an early diversity lead only to be surpassed by other groups that were more ecologically diverse and less evolutionarily volatile, with steady diversification rates and strong resistance to mass extinctions," adds Knope.

Please Note: The 2020 American Physical Society (APS) March Meeting that was to be held in Denver, Colorado from March 2 through March 6 has been canceled. The decision was made late Saturday (February 29), out of an abundance of caution and based on the latest scientific data available regarding the transmission of the coronavirus disease (COVID-19). See our official release on the cancelation for more details.

DENVER, COLO., FEBRUARY 28, 2020--Physics is more than black holes, quarks and dark matter. It plays an integral role in our daily lives, from understanding election interference to how we cook spaghetti. Although public trust in science is growing, a recent survey indicates that people are skeptical when it comes to research integrity and tend to trust practitioners more than research scientists.

To bridge this divide, science communicators at the 2020 American Physical Society March Meeting in Denver will present unique and engaging approaches to leverage popular culture to bring physics to life in a way that intrigues, fascinates, and mobilizes the general public.

Need for Speed

The author of The Physics of Nascar, former nanomaterials researcher Diandra Leslie-Pelecky, will deliver a public lecture on Tuesday, March 3, titled "From Nanomaterials to NASCAR: Materials at 200 Miles per Hour." Then, in a talk during the Physics for Everyone session on March 5, she will share from her experience from the science communication trenches and advise March Meeting scientists on how they can help broaden the public's perception of physics.

"People are hard-wired to learn from story, so scientists should learn the basics of storytelling," said Leslie-Pelecky. "Understand your audience and what motivates them, find the overlap between your passions and theirs, because outreach to the public is not about you, the scientist, but about them."

In her public lecture, Leslie-Pelecky will discuss how materials contribute to speed and safety, including how technology developed by NASA has been incorporated into race cars, and how safety innovations in NASCAR impact the roads everyone drivers.

Science Goes to the Movies

The cultural phenomenon of Star Wars has entranced and captivated movie-goers for several generations. Patrick Johnson, assistant teaching professor in the Department of Physics at Georgetown University, will share his love of this classic movie. His presentation will examine the various theories behind the science of Star Wars. His talk will be a treat for science fiction and physics fans alike.

Star Wars has paved the way for the Marvel and DC universe to take over the summer blockbuster movie schedule. Both superheroes and supervillains possess powers that defy nature. James Kakalios will explain the links between superpowers and modern technologies. His presentation will explore how concepts in comics are now appearing as new technologies in the marketplace, from Spiderman's webbing and carbon nanotubes to Black Panther's Vibranium suit and the conservation of energy.

"There is a growing appreciation by the physics community that outreach to the general public, communicating the principles, findings and benefits of physics research, is an important activity," said James Kakalios, professor of physics and astronomy at the University of Minnesota. "I hope that this session can help inspire other physicists to combine their passion for physics with their other interests [to demonstrate] that science is not an esoteric subject, but is the basis for our modern lifestyles."

Anissa Ramirez, professor, inventor and science evangelist with Science Underground, will round out the session by discussing how to leverage popular culture to bring scientific ideas to life for the general public. Ramirez will explore topics from her forthcoming book, "The Alchemy of Us," on ways to embed science into stories that will appeal to the broadest audience, like drawing the link between the gas laws and 'deflate-gate' in American football.

Chocolate Covered Physics

Wilson Poon, professor of physics at the University of Edinburgh, will explore the physics responsible for the smooth, velvety texture of chocolate during the Flow and Structure in Dense Suspensions session on March 2. His presentation will examine how mixing (the conching process) affects the physical properties of chocolate during processing. Poon believes the results of the study could be used to reduce the fat content and energy needed to produce this delightful confection.