Monday, November 30, 2020

Chemical Compounds in These Foods Can Inhibit a Key SARS-CoV-2 Enzyme



Chemical compounds in foods or beverages like green tea, muscadine grapes and dark chocolate can bind to and block the function of a particular enzyme, or protease, in the SARS-CoV-2 virus, according to a new study by plant biologists at North Carolina State University.

Chemical compounds in muscadine grapes effectively inhibit an important SARS-CoV-2 protease



Credit: De-Yu Xie, NC State University

Proteases are important to the health and viability of cells and viruses, says De-Yu Xie, professor of plant and microbial biology at NC State and the corresponding author of the study. If proteases are inhibited, cells cannot perform many important functions - like replication, for example.

"One of our lab's focuses is to find nutraceuticals in food or medicinal plants that inhibit either how a virus attaches to human cells or the propagation of a virus in human cells," Xie said.

In the study, the NC State researchers performed both computer simulations and lab studies showing how the so-called "main protease" (Mpro) in the SARS-CoV-2 virus reacted when confronted with a number of different plant chemical compounds already known for their potent anti-inflammatory and antioxidant properties.

"Mpro in SARS-CoV-2 is required for the virus to replicate and assemble itself," Xie said. "If we can inhibit or deactivate this protease, the virus will die."

Computer simulations showed that the studied chemical compounds from green tea, two varieties of muscadine grapes, cacao powder and dark chocolate were able to bind to different portions of Mpro.

"Mpro has a portion that is like a 'pocket' that was 'filled' by the chemical compounds," Xie said. "When this pocket was filled, the protease lost its important function."

In vitro lab experiments completed by Yue Zhu, an NC State Ph.D. student in Xie's lab, showed similar results. The chemical compounds in green tea and muscadine grapes were very successful at inhibiting Mpro's function; chemical compounds in cacao powder and dark chocolate reduced Mpro activity by about half.

"Green tea has five tested chemical compounds that bind to different sites in the pocket on Mpro, essentially overwhelming it to inhibit its function," Xie said. "Muscadine grapes contain these inhibitory chemicals in their skins and seeds. Plants use these compounds to protect themselves, so it is not surprising that plant leaves and skins contain these beneficial compounds."
 


Contacts and sources: 
De-Yu Xie,
 NC State University





Publication: Docking characterization and in vitro inhibitory activity of flavan-3-ols and dimeric proanthocyanidins against the main protease activity of SARS-Cov-2

Authors: Yue Zhu and De-Yu Xie, NC State University

Published: Nov. 30, 2020 in Frontiers in Plant Science

DOI: 10.3389/fpls.2020.601316

New Hubble Data Explains Missing Dark Matter

In 2018 an international team of researchers using the NASA/ESA Hubble Space Telescope and several other observatories uncovered, for the first time, a galaxy in our cosmic neighborhood that is missing most of its dark matter. This discovery of the galaxy NGC 1052-DF2 was a surprise to astronomers, as it was understood that dark matter is a key constituent in current models of galaxy formation and evolution. In fact, without the presence of dark matter, the primordial gas would lack enough gravitational pull to start collapsing and forming new galaxies. A year later, another galaxy that misses dark matter was discovered, NGC 1052-DF4, which further triggered intense debates among astronomers about the nature of these objects.

New data from the NASA/ESA Hubble Space Telescope provides further evidence for tidal disruption in the galaxy NGC 1052-DF4. This result explains a previous finding that this galaxy is missing most of its dark matter. By studying the galaxy’s light and globular cluster distribution, astronomers have concluded that the gravitational forces of the neighboring galaxy NGC 1035 stripped the dark matter from NGC 1052-DF4 and are now tearing the galaxy apart. This image, created from images forming part of the Digitized Sky Survey 2, shows the sky around NGC 1052-DF4.


Credits: ESA/Hubble, NASA, Digitized Sky Survey 2; Acknowledgment: Davide de Martin


Now, new Hubble data have been used to explain the reason behind the missing dark matter in NGC 1052-DF4, which resides 45 million light-years away. Mireia Montes of the University of New South Wales in Australia led an international team of astronomers to study the galaxy using deep optical imaging. They discovered that the missing dark matter can be explained by the effects of tidal disruption. The gravity forces of the neighboring massive galaxy NGC 1035 are tearing NGC 1052-DF4 apart. During this process, the dark matter is removed, while the stars feel the effects of the interaction with another galaxy at a later stage.

Until now, the removal of dark matter in this way has remained hidden from astronomers as it can only be observed using extremely deep images that can reveal extremely faint features. “We used Hubble in two ways to discover that NGC 1052-DF4 is experiencing an interaction,” explained Montes. “This includes studying the galaxy’s light and the galaxy’s distribution of globular clusters.” 

This image presents the region around the galaxy NGC 1052-DF4, taken by the IAC80 telescope at the Teide Observatory in Tenerife, Spain. The figure highlights the main galaxies in the field of view, including NGC 1052-DF4 (center of the image) and its neighbor NGC 1035 (center left).


Credits: M. Montes et al.


Thanks to Hubble’s high resolution, the astronomers could identify the galaxy’s globular cluster population. The 10.4-meter Gran Telescopio Canarias (GTC) telescope and the IAC80 telescope in the Canary Islands of Spain were also used to complement Hubble’s observations by further studying the data.

“It is not enough just to spend a lot of time observing the object, but a careful treatment of the data is vital,” explained team member Raúl Infante-Sainz of the Instituto de Astrofísica de Canarias in Spain. “It was therefore important that we use not just one telescope/instrument, but several (both ground- and space-based) to conduct this research. With the high resolution of Hubble, we can identify the globular clusters, and then with GTC photometry we obtain the physical properties.”

Globular clusters are thought to form in the episodes of intense star formation that shaped galaxies. Their compact sizes and luminosity make them easily observable, and they are therefore good tracers of the properties of their host galaxy. In this way, by studying and characterizing the spatial distribution of the clusters in NGC 1052-DF4, astronomers can develop insight into the present state of the galaxy itself. The alignment of these clusters suggests they are being “stripped” from their host galaxy, and this supports the conclusion that tidal disruption is occurring.

By studying the galaxy’s light, the astronomers also found evidence of tidal tails, which are formed of material moving away from NGC 1052-DF4. This further supports the conclusion that this is a disruption event. Additional analysis concluded that the central parts of the galaxy remain untouched and only about 7% of the stellar mass of the galaxy is hosted in these tidal tails. This means that dark matter, which is less concentrated than stars, was previously and preferentially stripped from the galaxy, and now the outer stellar component is starting to be stripped as well.

“This result is a good indicator that, while the dark matter of the galaxy was evaporated from the system, the stars are only now starting to suffer the disruption mechanism,” explained team member Ignacio Trujillo of the Instituto de Astrofísica de Canarias in Spain. “In time, NGC 1052-DF4 will be cannibalized by the large system around NGC 1035, with at least some of their stars floating free in deep space.”

The discovery of evidence to support the mechanism of tidal disruption as the explanation for the galaxy’s missing dark matter has not only solved an astronomical conundrum, but has also brought a sigh of relief to astronomers. Without it, scientists would be faced with having to revise our understanding of the laws of gravity.

“This discovery reconciles existing knowledge of how galaxies form and evolve with the most favorable cosmological model,” added Montes.



Contacts and sources:
Claire Andreoli
NASA/Goddard Space Flight Center





 

Friday, November 27, 2020

Ancient Banket Made with 11,500 Turkey Feathers



The ancient inhabitants of the American Southwest used around 11,500 feathers to make a turkey feather blanket, according to a new paper in the Journal of Archaeological Science: Reports. The people who made such blankets were ancestors of present-day Pueblo Indians such as the Hopi, Zuni and Rio Grande Pueblos.

A team led by Washington State University archaeologists analyzed an approximately 800-year-old, 99 x 108 cm (about 39 x 42.5 inches) turkey feather blanket from southeastern Utah to get a better idea of how it was made. Their work revealed thousands of downy body feathers were wrapped around 180 meters (nearly 200 yards) of yucca fiber cord to make the blanket, which is currently on display at the Edge of the Cedars State Park Museum in Blanding, Utah.

A segment of fiber cord that has been wrapped with turkey feathers, along with a single downy feather.


Credit: WSU

The researchers also counted body feathers from the pelts of wild turkeys purchased from ethically and legally compliant dealers in Idaho to get an estimate of how many turkeys would have been needed to provide feathers for the blanket. Their efforts show it would have taken feathers from between four to 10 turkeys to make the blanket, depending on the length of feathers selected.

“Blankets or robes made with turkey feathers as the insulating medium were widely used by Ancestral Pueblo people in what is now the Upland Southwest, but little is known about how they were made because so few such textiles have survived due to their perishable nature,” said Bill Lipe, emeritus professor of anthropology at WSU and lead author of the paper. “The goal of this study was to shed new light on the production of turkey feather blankets and explore the economic and cultural aspects of raising turkeys to supply the feathers.”

Clothing and blankets made of animal hides, furs or feathers are widely assumed to have been innovations critical to the expansion of humans into cold, higher latitude and higher elevation environments, such as the Upland Southwest of the United States where most of the early settlements were at elevations above 5,000 feet.

Previous work by Lipe and others shows turkey feathers began to replace strips of rabbit skin in construction of twined blankets in the region during the first two centuries C.E. Ethnographic data suggest the blankets were made by women and were used as cloaks in cold weather, blankets for sleeping and ultimately as funerary wrappings.

Bill Lipe and Shannon Tushingham collect feathers from a wild turkey pelt in Tushingham’s lab at WSU.

Credit: WSU

“As ancestral Pueblo farming populations flourished, many thousands of feather blankets would likely have been in circulation at any one time,” said Shannon Tushingham, a co-author on the study and assistant professor of anthropology at WSU. “It is likely that every member of an ancestral Pueblo community, from infants to adults, possessed one.”

Another interesting finding of the study was the turkey feathers used by the ancestral Pueblo people to make garments were most likely painlessly harvested from live birds during natural molting periods. This would have allowed sustainable collection of feathers several times a year over a bird’s lifetime, which could have exceeded 10 years. Archeological evidence indicates turkeys were generally not used as a food source from the time of their domestication in the early centuries C.E. until the 1100s and 1200s C.E., when the supply of wild game in the region had become depleted by over-hunting.

Prior to this period, most turkey bones reported from archaeological sites are whole skeletons from mature birds that were intentionally buried, indicating ritual or cultural significance. Such burials continued to occur even after more turkeys began to be raised for food.

“When the blanket we analyzed for our study was made, we think in the early 1200s C.E., the birds that supplied the feathers were likely being treated as individuals important to the household and would have been buried complete,” Lipe said. “This reverence for turkeys and their feathers is still evident today in Pueblo dances and rituals. They are right up there with eagle feathers as being symbolically and culturally important.”

In the long run, the researchers said their hope is the study will help people appreciate the importance of turkeys to Native American cultures across the Southwest.

“Turkeys were one of the very few domesticated animals in North America until Europeans arrived in the 1500s and 1600s,” Tushingham said. “They had and continue to have a very culturally significant role in the lives of Pueblo people, and our hope is this research helps shed light on this important relationship.”



Contacts and sources:
Bill Lipe/ Will Ferguson
Washington State University





Publication: http://dx.doi.org/10.1016/j.jasrep.2020.102604

Microvehicle Ferries Drugs Though the Blood Stream, Unloads Medicinal Cargo Where It Needs To Go



Robots so tiny that they can manoeuvre through our blood vessels and deliver medications to certain points in the body - researchers have been pursuing this goal for years. Now, scientists at ETH Zurich have succeeded for the first time in building such "micromachines" out of metal and plastic, in which these two materials are interlocked as closely as links in a chain. This is possible thanks to a new manufacturing technique they have devised.

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Credit: ETH Zurich

"Metals and polymers have different properties, and both materials offer certain advantages in building micromachines. Our goal was to benefit from all these properties simultaneously by combining the two," explains Carlos Alcântara, formerly a doctoral student in Salvador Pané's group at the Institute of Robotics and Intelligent Systems and one of the two lead authors of the paper. As a rule, micromachines are powered from outside the body using magnetic fields, which means they must have magnetic metal parts installed. Polymers, in contrast, have the advantage that they can be used to construct soft, flexible components as well as parts that dissolve inside the body. If medication is embedded in this kind of soluble polymer, it is possible to selectively supply active substances to certain points in the body.

High-tech production method

Underpinning the new manufacturing method is the expertise of ETH Professor Salvador Pané. For years, he has been working with a high-precision 3D printing technique that produces complex objects on the micrometre level, a technique known as 3D lithography. The ETH scientists applied this method to produce a kind of mould or template for their micromachines. These templates have narrow grooves that serve as a "negative" and can be filled with the chosen materials.
Credit: ETH Zurich

Using electrochemical deposition, the scientists fill some of the grooves with metal and others with polymers before ultimately dissolving the template away with solvents. "Our interdisciplinary group consists of electrical engineers, mechanical engineers, chemists, and materials scientists who all work closely together. That was the key to developing this method," says Fabian Landers, a doctoral student in Pané's group. He is the other lead author of the paper, which has been published in the journal Nature Communications.

Vehicle with tiny magnetic wheels

As a proof of principle for making micromachines by interlocking materials, the ETH scientists created various miniscule vehicles with plastic chassis and magnetic metal wheels powered by means of a rotating magnetic field. Some of the vehicles can be propelled across a glass surface, while others - depending on the polymer used - can float in liquid or on a liquid surface.

The scientists are now planning to refine their two-component micromachines and experiment with other materials. In addition, they will attempt to create more complex shapes and machines, including some that can fold and unfold themselves. Besides serving as "ferries" that distribute active substances, future applications of micromachines include treating aneurysms (bulges in blood vessels) or performing other surgical procedures. Another research goal is to make stents (tube shaped vessel supports) that unfold themselves and can be positioned at a specific place in the body using magnetic fields.



Contacts and sources:
Salvador Pané
ETH Zurich


Publication: Mechanically interlocked 3D multi-material micromachines C. C. J. Alcântara, F. C. Landers, S. Kim, C. De Marco, D. Ahmed, B. J. Nelson & S. Pané Nature Communications volume 11, Article number: 5957 (2020) https://www.nature.com/articles/s41467-020-19725-6 http://dx.doi.org/10.1038/s41467-020-19725-6 

World’s Smallest Atom-Memory Unit Created

Faster, smaller, smarter and more energy-efficient chips for everything from consumer electronics to big data to brain-inspired computing could soon be on the way after engineers at The University of Texas at Austin created the smallest memory device yet. And in the process, they figured out the physics dynamic that unlocks dense memory storage capabilities for these tiny devices.

The research published recently in Nature Nanotechnology builds on a discovery from two years ago, when the researchers created what was then the thinnest memory storage device. In this new work, the researchers reduced the size even further, shrinking the cross section area down to just a single square nanometer.

Credit: University of Texas Austin

Getting a handle on the physics that pack dense memory storage capability into these devices enabled the ability to make them much smaller. Defects, or holes in the material, provide the key to unlocking the high-density memory storage capability.

“When a single additional metal atom goes into that nanoscale hole and fills it, it confers some of its conductivity into the material, and this leads to a change or memory effect,” said Deji Akinwande, professor in the Department of Electrical and Computer Engineering.

Though they used molybdenum disulfide – also known as MoS2 – as the primary nanomaterial in their study, the researchers think the discovery could apply to hundreds of related atomically thin materials.

The race to make smaller chips and components is all about power and convenience. With smaller processors, you can make more compact computers and phones. But shrinking down chips also decreases their energy demands and increases capacity, which means faster, smarter devices that take less power to operate.

“The results obtained in this work pave the way for developing future generation applications that are of interest to the Department of Defense, such as ultra-dense storage, neuromorphic computing systems, radio-frequency communication systems and more,” said Pani Varanasi, program manager for the U.S. Army Research Office, which funded the research.

The original device – dubbed “atomristor” by the research team – was at the time the thinnest memory storage device ever recorded, with a single atomic layer of thickness. But shrinking a memory device is not just about making it thinner but also building it with a smaller cross-sectional area.

“The scientific holy grail for scaling is going down to a level where a single atom controls the memory function, and this is what we accomplished in the new study,” Akinwande said.

Akinwande’s device falls under the category of memristors, a popular area of memory research, centered around electrical components with the ability to modify resistance between its two terminals without a need for a third terminal in the middle known as the gate. That means they can be smaller than today’s memory devices and boast more storage capacity.

This version of the memristor – developed using the advanced facilities at the Oak Ridge National Laboratory – promises capacity of about 25 terabits per square centimeter. That is 100 times higher memory density per layer compared with commercially available flash memory devices.



Contacts and sources:
Nat Levy
Cockrell School of Engineering
University of Texas Austin


Publication: Observation of single-defect memristor in an MoS2 atomic sheet Saban M. Hus, Ruijing Ge, Po-An Chen, Liangbo Liang, Gavin E. Donnelly, Wonhee Ko, Fumin Huang, Meng-Hsueh Chiang, An-Ping Li & Deji Akinwande Nature Nanotechnology (2020) https://www.nature.com/articles/s41565-020-00789-w http://dx.doi.org/10.1038/s41565-020-00789-w



Think Better with Chocolate: Cocoa Flavanols Boost Brain Oxygenation, Cognition in Healthy Adults

The brains of healthy adults recovered faster from a mild vascular challenge and performed better on complex tests if the participants consumed cocoa flavanols beforehand, researchers report in the journal Scientific Reports. In the study, 14 of 18 participants saw these improvements after ingesting the flavanols.

Previous studies have shown that eating foods rich in flavanols can benefit vascular function, but this is the first to find a positive effect on brain vascular function and cognitive performance in young healthy adults, said Catarina Rendeiro, a researcher and lecturer in nutritional sciences at the University of Birmingham who led the research with University of Illinois at Urbana-Champaign psychology professors Monica Fabiani and Gabriele Gratton.

Cocoa pod growing at the trunk of a cocoa tree at the Maison du cacao, Guadeloupe
Credit: Pkraemer / Wikimedia Commons


“Flavanols are small molecules found in many fruits and vegetables, and cocoa, too,” Rendeiro said. “They give fruits and vegetables their bright colors, and they are known to benefit vascular function. We wanted to know whether flavanols also benefit the brain vasculature, and whether that could have a positive impact on cognitive function.”

The team recruited adult nonsmokers with no known brain, heart, vascular or respiratory disease, reasoning that any effects seen in this population would provide robust evidence that dietary flavanols can improve brain function in healthy people.

The team tested the 18 participants before their intake of cocoa flavanols and in two separate trials, one in which the subjects received flavanol-rich cocoa and another during which they consumed processed cocoa with very low levels of flavanols. Neither the participants nor researchers knew which type of cocoa was consumed in each of the trials. This double-blind study design prevents researchers’ or participants’ expectations from affecting the results.


With their colleagues, U. of I. psychology professors Gabriele Gratton, left, and Monica Fabiani found evidence that ingesting flavanols can positively influence neurovascular health and brain function.

Photo courtesy Beckman Institute


About two hours after consuming the cocoa, participants breathed air with 5% carbon dioxide – about 100 times the normal concentration in air. This is a standard method for challenging brain vasculature to determine how well it responds, Gratton said.

The body typically reacts by increasing blood flow to the brain, he said.

“This brings in more oxygen and also allows the brain to eliminate more carbon dioxide,” he said.

With functional near-infrared spectroscopy, a technique that uses light to capture changes in blood flow to the brain, the team measured oxygenation in the frontal cortex, a brain region that plays a key role in planning, regulating behavior and decision-making.

“This allows you to measure how well the brain defends itself from the excess carbon dioxide,” Fabiani said.

Researchers also challenged participants with complex tasks that required them to manage sometimes contradictory or competing demands.

Most of the participants had a stronger and faster brain oxygenation response after exposure to cocoa flavanols than they did at baseline or after consuming cocoa lacking flavanols, the researchers found.

“The levels of maximal oxygenation were more than three times higher in the high-flavanol cocoa versus the low-flavanol cocoa, and the oxygenation response was about one minute faster,” Rendeiro said.

After ingesting the cocoa flavanols, participants also performed better on the most challenging cognitive tests, correctly solving problems 11% faster than they did at baseline or when they consumed cocoa with reduced flavanols. There was no measurable difference in performance on the easier tasks, however.

University of Birmingham lecturer in nutritional sciences Catarina Rendeiro found that cocoa flavanols improve brain oxygenation and cognition in healthy adults.


Credit: Catarina Rendeiro

“This suggests that flavanols might only be beneficial during cognitive tasks that are more challenging,” Rendeiro said.

Participants varied in their responses to cocoa flavanols, the researchers found.

“Although most people benefited from flavanol intake, there was a small group that did not,” Rendeiro said. Four of the 18 study subjects had no meaningful differences in brain oxygenation response after consuming flavanols, nor did their performance on the tests improve.

“Because these four participants already had the highest oxygenation responses at baseline, this may indicate that those who are already quite fit have little room for improvement,” Rendeiro said. “Overall, the findings suggest that the improvements in vascular activity after exposure to flavanols are connected to the improvement in cognitive function.”

Fabiani and Gratton are affiliates of the Beckman Institute for Advanced Science and Technology at the U. of I.

A Birmingham-Illinois Seed Grant and the National Institute on Aging supported this research.



Contacts and sources:
Diana Yates






Publication: "Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults"




Which Approaches Are Most Effective at Reducing COVID-19 Spread Examined

Researchers developed a model to test the effectiveness of measures such as physical distancing, masks or social bubbles when used in various settings. 

Their paper was published Nov. 19 in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).



Credit: Mayor Marty Walsh / Wikimedia Commmons

They introduce the concept of “event R,” which is the expected number of people who become infected with COVID-19 from one individual at an event. 

Tupper and Colijn look at factors such as transmission intensity, duration of exposure, the proximity of individuals and degree of mixing – then examine what methods are most effective at preventing transmission in each circumstance. 

The researchers incorporated data from reports of outbreaks at a range of events, such as parties, meals, nightclubs, public transit and restaurants. The researchers say that an individual’s chances of becoming infected with COVID-19 depend heavily on the transmission rate and the duration - the amount of time spent in a particular setting.

Events were categorized as saturating (high transmission probability) or linear (low transmission probability). Examples of high transmission settings include bars, nightclubs and overcrowded workplaces while low transmission settings include public transit with masks, distancing in restaurants and outdoor activities. 

The model suggests that physical distancing was effective at reducing COVID-19 transmission in all settings but the effectiveness of social bubbles depends on whether chances of transmission are high or low.

In settings where there is mixing and the probability of transmission is high, such as crowded indoor workplaces, bars and nightclubs and high schools, having strict social bubbles can help reduce the spread of COVID-19.

The researchers found that social bubbles are less effective in low transmission settings or activities where there is mixing, such as engaging in outdoor activities, working in spaced offices or travelling on public transportation wearing masks. 

They note that masks and other physical barriers may be less effective in saturating, high transmission settings (parties, choirs, restaurant kitchens, crowded offices, nightclubs and bars) because even if masks halve the transmission rates that may not have much impact on the transmission probability (and so on the number of infections).

The novel coronavirus is relatively new but the science continues to evolve and increase our knowledge of how to effectively treat and prevent this highly contagious virus. There is still much that we do not know and many areas requiring further study. 

“It would be great to start collecting information from exposures and outbreaks: the number of attendees, the amount of mixing, the levels of crowding, the noise level and the duration of the event,” says Colijn, who holds a Canada Research Chair in Mathematics for Evolution, Infection and Public Health.





Contacts and sources: 
Melissa Shaw
Simon Fraser University

 


Publication: Event-specific interventions to minimize COVID-19 transmission.
Paul Tupper, Himani Boury, Madi Yerlanov, Caroline Colijn. Proceedings of the National Academy of Sciences, 2020; 202019324 DOI: 10.1073/pnas.2019324117


Monday, November 23, 2020

COVID Shocks to Seafood Market

Research shows that typical seafood distribution in the United States dropped steeply at the start of the global pandemic.


Credit: UCSB/iStock


The United States’ seafood industry declined precipitously in the months following the emergence of the COVID-19 pandemic, and research shows that targeted federal assistance will be necessary to bring it back.

UC Santa Barbara aquaculture and fisheries professor Halley Froehlich and colleagues suspected as much early on in the pandemic, but for something as large and complex as the seafood industry, the trends were not so obvious. As a result, financial assistance in that direction has been slow.

“Seafood is part of the narrative that I would say doesn’t get as much attention as something like agriculture,” said Froehlich, an author of a study published in the journal Fish and Fisheries. “And that certainly appears to be the case when we’re looking at something like the CARES Act, the federal funding source specifically passed to provide economic relief in the U.S.”

That is, in large part, due to the fact that policymakers lack sufficient real-time data to see how the seafood industry is faring in the time of lockdowns and social distancing, said the study’s lead author, University of Vermont ecologist Easton White.

“One difficulty is that a lot of this data isn’t released until months and years later,” he said. From the boat to the table, data is generated that must be gathered and processed before it gets released, he explained.

The pandemic is a rapidly evolving situation and the seafood industry can’t afford to wait. So, to get a big-picture look at the early effects of COVID-19 on U.S. fisheries and seafood consumption, Froehlich, White and fellow fisheries data experts synthesized multiple sources from across the seafood supply chain, including some unconventional real-time data sets.

“We looked for different indicators of the effects of COVID on seafood and fisheries in general,” White said. In addition to federal fisheries reports and customs data, the researchers looked to news reports and Google search trends for seafood and seafood market foot traffic.

Lessons Learned
As had happened for virtually every industry at the start of the pandemic, the lockdowns and closures caused a huge drop in economic activity for the seafood sector, from which many still struggle to recover. Using data from January to September 2020, the researchers calculated a 40% decline in fresh seafood catches, a 37% decline in imports and a 43% drop in exports relative to the same time last year. These impacts are expected to reverberate across the globe, as the U.S. is one of the top exporters and importers of seafood.

Closer to home, demand from restaurants — the main driver of seafood spending in the U.S. — virtually disappeared as establishments locked down. Seafood market foot traffic declined steeply as well.

The effects were uneven across fisheries and aquaculture operations.

“Large-scale production systems that have large networks were able to pivot really fast,” Froehlich said. “And so if they couldn’t sell in one location, they were more easily able to sell to a different location. They felt the impacts, but not as much as the small scale fisheries that then had to depend on looking for local buyers.”

Frozen seafood products, according to the paper, “were generally less affected.”

One interesting development has been the uptick in seafood delivery and takeout, which has been picking up some — but not all — of the slack in restaurant demand.

“It’s unclear to us the level of substitution and what it means in the long term, especially how people are consuming seafood at home,” said Froehlich, who is interested in how this consumption pattern might influence the demand for certain species over time.

Because of COVID-19’s variable effects across the entire seafood industry, according to the researchers, future federal support should be aimed at locations and sub-sectors “most affected by the pandemic: fishery-dependent communities, processors and fisheries and aquaculture that focus on fresh products.”

“A lot of communities are dependent on fisheries,” White said. “There are fisheries for tourism, for livelihoods, and a lot of indigenous communities focus on fishing. And it’s not just fishing but also fish processing, all the different people that are involved. If you have COVID popping up just when you’re about to go fishing and make all the money you’re going to have for the year, now you can’t make any of that.”

The pandemic has highlighted some of the stress points in the U.S.’s seafood supply chain, the researchers said. Preserving a diversity of the sub-sectors within the seafood industry — for instance, small local operations as well as large fisheries — will keep the entire system resilient to shocks.

“If you have locally-sourced seafood, if you have aquaculture and fisheries, if you have small-scale and large-scale, this is a little more robust,” White said.

This study is the first to be produced from the wealth of data the researchers gathered. A parallel study will publish in the journal Marine Policy that examines how policy, particularly the new federal seafood acts and executive orders, can support more integrated management and diversification of the US seafood sector. The researchers hope the information will help guide the rebuilding of the flagging U.S. seafood industry to be more resilient to future shocks, including climate change impacts.

“As new mandates and legislation around fisheries and aquaculture are being rolled out during COVID-19 at the national and state levels, we have an opportunity to really think about what the actual targets and goals are. How do we build in more resilience now, instead of retroactively, when the system gets disrupted again,” Froehlich said. “Because it will.”

Research in this study was conducted also by Richard S. Cottrell at UCSB; Jessica A. Gephart at American University, Trevor A. Branch at University of Washington, Rahul Agrawal Bejarano at University of Michingan and Julia K. Baum at University of Victoria

The study is available at: https://onlinelibrary.wiley.com/doi/10.1111/faf.12525

Contacts and sources:
Sonia Fernandez
University of California Santa Barbara 



 





COVID-19 Cases Could Nearly Double to 20 Million before Biden Takes Office

President-elect Joe Biden has signaled that fighting the COVID-19 pandemic will be an immediate priority for his administration. He recently announced a coronavirus advisory board of infectious disease researchers and former public health advisers along with an updated strategy that will include increases in testing and contact tracing, as well as transparent communication.

But Inauguration Day is still two months away. The number of confirmed COVID-19 cases are likely to increase to 20 million by the end of January, nearly doubling the current level of 11.4 million cases, predicts a Washington University in St. Louis COVID-19 forecasting model.

The model, which accurately forecasted the rate of COVID-19 growth over the summer of 2020, was developed by Olin Business School’s Meng Liu, Raphael Thomadsen and Song Yao. Their paper presenting the model and its forecasts was published Nov. 23 by Scientific Reports.

“One of the key reasons for the increased accuracy of this model over other COVID-19 forecasts is that this model accounts for the fact that people live in interconnected social networks rather than interacting mostly with random groups of strangers,” said Thomadsen, professor of marketing. “This allows the model to forecast that growth will not continue at exponential rates for long periods of time, as classic COVID-19 forecasts predict.”

The evolution of COVID-19 depends on how much we, as a country, continue to social distance or return back to normal levels of interaction. This chart shows forecasted cases in the U.S. through the end of January 2021 based on our current social distancing levels, as well as less and more social distancing.

Credit: Washington University in St Louis


An interactive online version of the model also allows users to observe the impact different levels of social distancing will have on the spread of COVID-19. The current social distancing reflects an approximate 60% return to normalcy, as compared with the level of social distancing before the pandemic. If we continue, as a nation, at the current level of social distancing, the model forecasts that we are likely to reach 20 million cases before the end of January 2021.

“Even small increases in social distancing can have a large effect on the number of cases we observe in the next two and a half months,” Thomadsen said. “Going back to a 50% return to normalcy, which was the average level of distancing in early August, would likely result in 5 million fewer cases by the end of January.

“We could effectively squash out the COVID growth within a few weeks if we went back to the levels of social distancing we experienced in April,” he added.

However, the researchers caution that this is likely a conservative estimate due to increased testing and the upcoming holidays.

“In our model, we assume that only 10% of cases are ever diagnosed, meaning that we will start to hit saturation,” said Song Yao, associate professor of marketing and study co-author. “However, more recently, testing has increased, and probably more like 25% of cases are diagnosed. In that case, total COVID cases would increase beyond 20 million in the next few months unless we, as a society, engage in more social distancing.”

“The upcoming holiday seasons will present a great deal of uncertainty to the outlook of the pandemic as people travel more at the end of the year. This will likely make our forecast an optimistic one,” said Meng Liu, assistant professor of marketing and study co-author.




Contacts and sources:
Sara Savat
Washington University in St Louis


Publication: Forecasting the spread of COVID-19 under different reopening strategies
Meng Liu, Raphael Thomadsen & Song Yao
Scientific Reports volume 10, Article number: 20367 (2020) http://dx.doi.org/10.1038/s41598-020-77292-8




The Drug Aprotinin Inhibits Entry of SARS-CoV2 in Host Cells

In order for the SARS-CoV2 virus to enter host cells, its “spike” protein has to be cleaved by the cell's own enzymes - proteases. The protease inhibitor aprotinin can prevent cell infection, as scientists at Goethe University, the University of Kent and the Hannover Medical School have now discovered. An aprotinin aerosol is already approved in Russia for the treatment of influenza and could readily be tested for the treatment of COVID-19.

Credit: Goethe University Frankfurt

The surface of the SARS-CoV-2 virus is studded with spike proteins. The virus needs these in order to dock onto proteins (ACE2 receptors) on the surface of the host cell. Before this docking is possible, parts of the spike protein have to be cleaved by the host cell's enzymes - proteases.

In cell culture experiments with various cell types, the international scientific team led by Professor Jindrich Cinatl, Institute for Medical Virology at the University Hospital Frankfurt), Professor Martin Michaelis, and Dr Mark Wass (both University of Kent) demonstrated that the protease inhibitor aprotinin can inhibit virus replication by preventing SARS-CoV2 entry into host cells. Moreover, aproticin appears to compensate for a SARS-CoV2-induced reduction of endogenous protease inhibitors in virus-infected cells.

Influenza viruses require host cell proteases for cell entry in a similar way as coronaviruses. Hence, an aprotinin aerosol is already approved in Russia for the treatment of influenza.

Professor Jindrich Cinatl said: “Our findings show that aprotinin is effective against SARS-CoV2 in concentrations that can be achieved in patients. In aprotinin we have a drug candidate for the treatment of COVID-19 that is already approved for other indications and could readily be tested in patients. "








Contacts and sources:
Jindrich Cinatl
Goethe University Frankfurt

Publication: Denisa Bojkova, Marco Bechtel, Katie-May McLaughlin, Jake E. McGreig, Kevin Klann, Carla Bellinghausen, Gernot Rohde, Danny Jonigk, Peter Braubach, Sandra Ciesek, Christian Münch, Mark N. Wass, Martin Michaelis, Jindrich Cinatl jr . Aprotinin inhibits SARS-CoV-2 replication . Cells 2020, https://www.mdpi.com/2073-4409/9/11/2377





Features That Could Make Someone a Virus Super-Spreader



New research from the University of Central Florida has identified physiological features that could make people super-spreaders of viruses such as COVID-19.

Sneeze velocity for four different nose and mouth types is shown. A is open nasal passage with teeth, B is open nasal passage without teeth, C is blocked nasal passage without teeth, and D is blocked nasal passage with teeth.
Credit: UCF


In a study appearing this month in the journal Physics of Fluids, researchers in UCF’s Department of Mechanical and Aerospace Engineering used computer-generated models to numerically simulate sneezes in different types of people and determine associations between people’s physiological features and how far their sneeze droplets travel and linger in the air.

They found that people’s features, like a stopped-up nose or a full set of teeth, could increase their potential to spread viruses by affecting how far droplets travel when they sneeze.

According to the U.S. Centers for Disease Control and Prevention, the main way people are infected by the virus that causes COVID-19 is through exposure to respiratory droplets, such as from sneezes and coughs that are carrying infectious virus.

Knowing more about factors affecting how far these droplets travel can inform efforts to control their spread, says Michael Kinzel, an assistant professor with UCF’s Department of Mechanical Engineering and study co-author.

“This is the first study that aims to understand the underlying ‘why’ of how far sneezes travel,” Kinzel says. “We show that the human body has influencers, such as a complex duct system associated with the nasal flow that actually disrupts the jet from your mouth and prevents it from dispersing droplets far distances.”

For instance, when people have a clear nose, such as from blowing it into a tissue, the speed and distance sneeze droplets travel decrease, according to the study.

This is because a clear nose provides a path in addition to the mouth for the sneeze to exit. But when people’s noses are congested, the area that the sneeze can exit is restricted, thus causing sneeze droplets expelled from the mouth to increase in velocity.

Similarly, teeth also restrict the sneeze’s exit area and cause droplets to increase in velocity.

“Teeth create a narrowing effect in the jet that makes it stronger and more turbulent,” Kinzel says. “They actually appear to drive transmission. So, if you see someone without teeth, you can actually expect a weaker jet from the sneeze from them.”

To perform the study, the researchers used 3D modeling and numerical simulations to recreate four mouth and nose types: a person with teeth and a clear nose; a person with no teeth and a clear nose; a person with no teeth and a congested nose; and a person with teeth and a congested nose.

When they simulated sneezes in the different models, they found that the spray distance of droplets expelled when a person has a congested nose and a full set of teeth is about 60 percent greater than when they do not.

The results indicate that when someone keeps their nose clear, such as by blowing it into a tissue, that they could be reducing the distance their germs travel.

The researchers also simulated three types of saliva: thin, medium and thick.

They found that thinner saliva resulted in sneezes comprised of smaller droplets, which created a spray and stayed in the air longer than medium and thick saliva.

For instance, three seconds after a sneeze, when thick saliva was reaching the ground and thus diminishing its threat, the thinner saliva was still floating in the air as a potential disease transmitter.

The work ties back to the researchers’ project to create a COVID-19 cough drop that would give people thicker saliva to reduce the distance droplets from a sneeze or cough would travel, and thus decrease disease-transmission likelihood.

The findings yield novel insight into variability of exposure distance and indicate how physiological factors affect transmissibility rates, says Kareem Ahmed, an associate professor in UCF’s Department of Mechanical and Aerospace Engineering and study co-author.

“The results show exposure levels are highly dependent on the fluid dynamics that can vary depending on several human features,” Ahmed says. “Such features may be underlying factors driving superspreading events in the COVID-19 pandemic.”

The researchers say they hope to move the work toward clinical studies next to compare their simulation findings with those from real people from varied backgrounds.

Study co-authors were Douglas Fontes, a postdoctoral researcher with the Florida Space Institute and the study’s lead author, and Jonathan Reyes, a postdoctoral researcher in UCF’s Department of Mechanical and Aerospace Engineering.

Fontes says to advance the findings of the study, the research team wants to investigate the interactions between gas flow, mucus film and tissue structures within the upper respiratory tract during respiratory events.

“Numerical models and experimental techniques should work side by side to provide accurate predictions of the primary breakup inside the upper respiratory tract during those events,” he says.

“This research potentially will provide information for more accurate safety measures and solutions to reduce pathogen transmission, giving better conditions to deal with the usual diseases or with pandemics in the future,” he says.

The work was funded by the National Science Foundation.

Kinzel received his doctorate in aerospace engineering from Pennsylvania State University and joined UCF in 2018. In addition to being a member of UCF’s Department of Mechanical and Aerospace engineering, a part of UCF’s College of Engineering and Computer Science, he also works with UCF’s Center for Advanced Turbomachinery and Energy Research.

Ahmed is an associate professor in UCF’s Department of Mechanical and Aerospace Engineering, a faculty member of the Center for Advanced Turbomachinery and Energy Research, and the Florida Center for Advanced Aero-Propulsion. He served more than three years as a senior aero/thermo engineer at Pratt & Whitney military engines working on advanced engine programs and technologies. He also served as a faculty member at Old Dominion University and Florida State University. At UCF, he is leading research in propulsion and energy with applications for power generation and gas-turbine engines, propulsion-jet engines, hypersonics and fire safety, as well as research related to supernova science and COVID-19 transmission control. He earned his doctoral degree in mechanical engineering from the State University of New York at Buffalo. He is an American Institute of Aeronautics and Astronautics associate fellow and a U.S. Air Force Research Laboratory and Office of Naval Research faculty fellow.






Contacts and sources:
Robert Wells
University of Central Florida

Publication: A study of fluid dynamics and human physiology factors driving droplet dispersion from a human sneeze. D. Fontes, J. Reyes, K. Ahmed, M. Kinzel. Physics of Fluids, 2020; 32 (11): 111904 DOI: 10.1063/5.0032006




Very Hungry And Angry, Caterpillars Head-Butt To Get What They Want

Inspired by his own butterfly garden at home, a Florida Atlantic University neuroscientist got a unique look at how monarch butterfly (Danaus plexippus) caterpillars behave when food is scarce. The results look something like a combination of boxing and “bumper” cars. With less access to their favorite food – milkweed – they go from docile to domineering, aggressively head-butting, lunging and knocking aside other caterpillars to ensure their own survival. And, they are most aggressive right before the final stages of their metamorphosis. A lack of nutrition during larval stages has been shown to delay larval development as well as reduce adult body size, reproductive performance and lifespan.

The less food, the more likely caterpillars were to try to head-butt each other out of the way to get their fill, lunging and knocking aside other caterpillars to ensure their own survival. And, they are most aggressive right before the final stages of their metamorphosis.

Credit: Florida Atlantic University

“Aggression is common in insects, including fruit flies, where single-pheromone receptors or single genes have been shown to trigger their aggression,” said Alex Keene, Ph.D., lead author and a professor of biological sciences, FAU’s Charles E. Schmidt College of Science. “I decided to investigate monarch caterpillars because I was intrigued by their combative behavior, which I observed first-hand in my own garden. They are large and easily recognizable compared to many other insects. These are charismatic animals that everyone loves, and there’s a growing appreciation for their potential to tell us about how the brain controls behavior.”

For the study, published in the journal iScience, researchers faced a number of challenges maintaining a population of monarchs while trying to model resource limitation. To encounter these challenges, Keene and his team built an open milkweed garden behind their Boca Raton-based lab and let nature do the work of collecting caterpillars. Back in the lab, the researchers placed caterpillars into groups with different amounts of milkweed. The results were clear – the less food, the more likely caterpillars were to try to head-butt each other out of the way to get their fill.

The process of getting to that result also was challenging. The researchers had difficulty breeding the monarchs in the lab, and found that almost every nursery sells their milkweed with pesticides. That’s why they ended up growing their own milkweed.

To examine whether caterpillars display aggressive behavior, Keene and collaborators quantified the presence of aggressive lunges under a number of conditions, as well as the effect of attacks on target conspecifics. Monarch caterpillars predominantly feed on milkweed and often strip entire plants bare of leaves over a two-week period. In many locations, milkweed is only available for part of the year, placing a significant constraint on monarch development. Monarchs also impact the milkweed plants they consume – at their largest and hungriest phase, a single caterpillar may devour an entire milkweed leaf in under five minutes.

“If you compare a monarch caterpillar to a fruit fly where there are lot of larvae on one piece of rotting fruit, you’ll find that they feed socially with little evidence of territoriality,” said Keene. “But each of these caterpillars will at some point in their developmental cycle encounter resource limitation because they can strip an entire milkweed of leaves.”

Credit: Florida Atlantic University

While observing the caterpillars, researchers noticed that the monarch’s tentacles, large mechanosensory appendages, were not utilized when they were being combative. This finding suggests that alternative sensory modalities, such as pheromonal, olfactory or tactile cues that are independent of the tentacles initiate aggression. The researchers believe that aggression induced by limited food availability in monarch caterpillars are likely present in many different species throughout the animal kingdom.

“While our research showed that the caterpillars respond aggressively to limited food, we still hope to learn more about what drives this response in their brains, which is important for learning more about how these responses work outside the lab,” said Keene. “One of the fundamental problems with work like this is that we’re testing animals in a very derived setting. And that’s not what brains evolved to do. So now that we have this invertebrate model in a relatively controlled setting, but doing an ecologically relevant behavior, that becomes important in terms of looking at the mechanism and function of this behavior in more complex organisms.”

Beyond the study of aggression in caterpillars, monarchs present an emerging model for studying the molecular mechanisms underlying behavior and set the stage for future investigations into the neuroethology of aggression in this system.

Study co-authors are Joseph Collie, Odelvys Granela, and Elizabeth B. Brown, Ph.D., all within FAU’s Department of Biological Sciences and the program in neurogenetics.

The research was supported by the National Science Foundation.



Contacts and sources: 
Gisele Galoustian
Florida Atlantic University


Publication: Aggression is induced by resource limitation in the monarch caterpillar.
Keene et al. iScience, 2020 DOI: 10.1016/j.isci.2020.101791






Giant Poisonous Rats So Lethal They Can Kill Elephants and Humans

The African crested rat (Lophiomys imhausi) is hardly the continent’s most fearsome-looking creature—the rabbit-sized rodent resembles a gray puffball crossed with a skunk—yet its fur is packed with a poison so lethal it can fell an elephant and just a few milligrams can kill a human
Credit: University of Utah 

In a Journal of Mammology paper published today, Smithsonian Conservation Biology Institute, University of Utah and National Museums of Kenya researchers found the African crested rat is the only mammal known to sequester plant toxins for chemical defense and uncovered an unexpected social life—the rats appear to be monogamous and may even form small family units with their offspring.

“It’s considered a ‘black box’ of a rodent,” said Sara Weinstein, lead author and Smithsonian-Mpala postdoctoral fellow and postdoctoral researcher at the University of Utah. “We initially wanted to confirm the toxin sequestration behavior was real and along the way discovered something completely unknown about social behavior. Our findings have conservation implications for this mysterious and elusive rat.”


An African crested rat is a rabbit-sized rodent that is the only known mammal to sequester plant toxins as a chemical defense 



Credit: Stephanie Higgins


People in East Africa have long suspected the rat to be poisonous. A 2011 paper proposed these large rodents sequester toxins from the poison arrow tree (Acokanthera schimperi). A source of traditional arrow poisons, Acokanthera contains cardenolides, compounds similar to those found in monarch butterflies, cane toads and some human heart medications. Cardenolides, particularly the ones in Acokanthera, are highly toxic to most animals.

“The initial 2011 study observed this behavior in only a single individual. A main goal of our study was to determine how common this exceptional behavior was,” said co-author Denise Dearing from the University of Utah.

When threatened, the African crested rat lives up to its name and erects a crest of hair on its back to reveal a warning on its flanks—black and white stripes running from neck-to-tail on each side of its body. The 2011 study hypothesized that the rats chew the Acokanthera bark and lick the plant toxins into specialized hairs at the center of these stripes.

In the new study, researchers trapped 25 African crested rats, the largest sample size of the species ever trapped. Using motion-activated cameras, they documented nearly 1,000 hours of rat behavior. For the first time, they recorded multiple rats sequestering Acokanthera toxins and discovered many traits that suggest they are social, and likely monogamous.

“Everyone thought it was a solitary animal. I’ve been researching this rat for more than ten years, so you would expect there to be fewer surprises,” said Bernard Agwanda, curator of Mammals at the Museums of Kenya, co-author of this study and the 2011 paper. “This can carry over into conservation policy.”

A rich social life

As a postdoctoral fellow at the Mpala Research Centre, Weinstein first searched for the rats with camera traps, but found that they rarely triggered the cameras. Weinstein was then joined by Katrina Nyawira, the paper’s second author and now a graduate student at Oxford Brookes University. Together, they spent months experimenting with live traps to capture the elusive rodents.

“We talked to rangers and ranchers to ask whether they’d seen anything.” said Nyawira. Eventually they figured out that loading the traps with smelly foods like fish, peanut butter and vanilla, did the trick. “Out of 30 traps, we finally got two animals. That was a win. This thing is really rare.”


Sara B. Weinstein (left), Katrina Nyawira (right) stand in front of Acokanthera schimperi, also known as the poison arrow tree. 


Credit:: Stephanie Higgins


Those two animals changed the course of the study. They first caught an individual female, then caught a male at the same site two days later.

“We put these two rats together in the enclosure and they started purring and grooming each other. Which was a big surprise, since everyone we talked to thought that they were solitary,” Weinstein said. “I realized that we had a chance to study their social interactions.”

Weinstein and Nyawira transformed an abandoned cow shed into a research station, constructing stalls equipped with ladders and nest boxes to simulate their habitat in tree cavities. They placed cameras in strategic spots of each pen and then analyzed every second of their footage, tracking the total activity, movement and feeding behavior. The aim was to build a baseline of normal behavior before testing whether behavior changed after the rats chewed the toxin cardenolides from the poison arrow tree.

“They’re herbivores, essentially rat-shaped little cows,” Weinstein said. “They spend a lot of time eating, but we also see them walk around, mate, groom, climb up the walls, sleep in the nest box.”

The footage and behavioral observations strongly support a monogamous lifestyle. They share many of the traits common among monogamous animals: large size, a long life span and a slow reproductive rate. Additionally, the researchers trapped a few large juveniles in the same location as adult pairs, suggesting that offspring spend an extended period of time with their parents. In the pens, the paired rats spent more than half of their time near each other, and frequently followed each other around. The researchers also recorded special squeaks, purrs and other communicative noises making up a wide vocal repertoire. Further behavioral studies and field observation would uncover more insights into their reproductive and family life.

A close up of a branch from Acokanthera schimperi. 



Credit: Sara B. Weinstein



After the researchers established a baseline of behavior, they offered rats branches from the poison arrow tree. Although rats did not sequester every time the plant was offered, 10 rats did at least once. They chewed it, mixed it with spit, and licked and chewed it into their specialized hairs. Exposure to the Acokanthera toxins did not alter rat behavior, and neither did eating milkweed, the same cardenolide-enriched plant used as chemical defense by monarch butterflies. Combined, these observations suggest that crested rats are uniquely resistant to these toxins.

“Most people think that it was a myth because of the potency of the tree,” said Nyawira. “But we caught it on video! It was very crazy.”

The rats were selective about using Acokanthera cardenolides, suggesting that rats may be picky about their toxin source, or that anointed toxins remain potent on the fur a long time, just like traditional arrow poisons from the same source.

African crested rat conservation

The African crested rat is listed as IUCN species of least concern, but there’s little actual data on the animals. Agwanda has studied African crested rats for more than a decade—and sees indications that they’re in trouble.

“We don’t have accurate numbers, but we have inferences. There was a time in Nairobi when cars would hit them and there was roadkill everywhere,” said Agwanda, who continues to monitor the populations. “Now encountering them is difficult. Our trapping rate is low. Their population is declining.”

The research team is planning future studies to better understand their physiology and behavior. “We are particularly interested in exploring the genetic mechanisms that allow the crested rats and their parasites to withstand the toxic cardenolides” said co-author Jesús Maldonado of the Smithsonian Conservation Biology Institute and Weinstein’s Smithsonian-Mpala Postdoctoral fellowship co-advisor.

“We are looking at a broad range of questions influenced by habitat change. Humans have cleared forests to make farms and roads. We need to understand how that impacts their survival,” Agwanda said. Additionally, Agwanda is building an exhibit at the Museums of Kenya to raise awareness about this unique poisonous animal.

Microscopic image of the specialized hairs that the African crested rat anoints with poison from Acokanthera schimperi 



PHOTO CREDIT: Sara B. Weinstein


About the Smithsonian’s National Zoo and Conservation Biology Institute

The Smithsonian’s National Zoo and Conservation Biology Institute leads the Smithsonian’s global effort to save species, better understand ecosystems and train future generations of conservationists. As Washington, D.C.’s favorite destination for families, the Zoo connects visitors to amazing animals and the people working to save them. In Front Royal, Virginia, across the United States and in more than 30 countries worldwide, Smithsonian Conservation Biology Institute scientists and animal care experts tackle some of today’s most complex conservation challenges by applying and sharing what they learn about animal behavior and reproduction, ecology, genetics, migration and conservation sustainability to save wildlife and habitats. Follow the Zoo on Facebook, Twitter and Instagram.

About the National Museums of Kenya
National Museums of Kenya (NMK) is a state corporation established by an Act of Parliament, the Museums and Heritage Act 2006. NMK is a multi-disciplinary institution whose role is to collect, preserve, study, document and present Kenya’s past and present cultural and natural heritage. This is for the purposes of enhancing knowledge, appreciation, respect and sustainable utilization of these resources for the benefit of Kenya and the world, for now and posterity. NMK’s mutual concern for the welfare of mankind and the conservation of the biological diversity of the East African region and that of the entire planet demands success in such efforts. In addition, NMK manages many Regional Museums, Sites and Monuments of national and international importance alongside priceless collections of Kenya’s living cultural and natural heritage. As an institution that must respond to the growing needs of the society, NMK is striving to contribute in a unique way to the task of national development.


Contacts and sources:
Lisa Potter
University of Utah



Publication: The secret social lives of African crested rats, Lophiomys imhausi.
Sara B Weinstein, Katrina Nyawira Malanga, Bernard Agwanda, Jesús E Maldonado, M Denise Dearing. Journal of Mammalogy, 2020 DOI: 10.1093/jmammal/gyaa127



Middle Stone Age Populations Repeatedly Occupied West African Coast



Excavations at Tiémassas, Senegal, indicate roughly 40,000 years of behavioural continuity, in contrast to other African regions over this period
 

In a study published in the Journal of Archaeological Science Reports, researchers from the Université Cheikh Anta Diop de Dakar, Senegal, the Max Planck Institute for the Science of Human History (MPI-SHH), and the University of Sheffield, reveal evidence of Middle Stone Age occupations of the West African coast. Ranging from 62 to 25 thousand years ago, the largest well-dated assemblages from the region clearly document technological continuity across almost 40,000 years in West Africa.


Lead author Khady Niang exploring the interface of forest, savannah and mangrove habitats close to Tiémassas

Credit: © J. Blinkhorn

Although coastlines have widely been proposed as potential corridors of past migration, the occupation of Africa’s tropical coasts during the Stone Age is poorly known, particularly in contrast to the temperate coasts of northern and southern Africa. Recent studies in eastern Africa have begun to resolve this, detailing dynamic behavioural changes near the coast of Kenya during the last glacial phase, but studies of Stone Age occupations along western Africa’s coasts are still lacking.

In recent years, anthropological research has begun to investigate the relationship between demographic diversity and patterns of behavioural change. A range of genetic and palaeoanthropological studies have begun to highlight the considerable demographic diversity present in West Africa in the recent past, but archaeological studies of Stone Age sites are still needed to understand how this diversity relates to patterns of behaviour shown in the archaeological record.

"There are plenty of surface sites that have demonstrated the wealth of Stone Age archaeology in West Africa," says Jimbob Blinkhorn of MPI-SHH, "but to characterise patterns of changing behaviour, we need large, excavated stone tool assemblages that we can clearly date to specific periods."


The excavation site at Tiémassas, which preserves evidence for Middle Stone Age occupations spanning 62-25 thousand years ago

Credit: © K. Niang

Tiémassas is a Stone Age site with a notable history of research, including surface surveys and early excavations in the mid-20th century, but the lack of systematic study meant it was mired in controversy.

"In the past, Tiémassas has been described as a Middle Stone Age, Later Stone Age or Neolithic site, and resolving between these alternatives has important implications for our understanding of behaviour at the site," says lead author Khady Niang of Université Cheikh Anta Diop de Dakar. "We've reviewed previously collected material from the site, conducted new excavations and analysis of stone tools and combined this with dating studies that make Tiémassas a benchmark example of the Middle Stone Age of West Africa."

Previous research by the team dated a Middle Stone Age occupation at Tiémassas to 45 thousand years ago. The new research extends the timeframe of occupations at the site, with further stone tool assemblages recovered dating to 62 thousand and 25 thousand years ago. Critically, these stone tool assemblages contain technologically distinct types that help to characterise the nature of stone tool production during each occupation phase.



A Levallois core recovered from excavations at Tiémassas, part of a common, persistent suite of stone tool technologies employed at the site between 62-25 thousand years ago[less]

Credit: © K. Niang

"The Middle Stone Age occupants of Tiémassas employed two distinct technologies - centripetal Levallois and discoidal reduction systems," says Niang. "What is really notable is that the stone tool assemblages are really consistent with one another and form a pattern we can match up with the results of earlier excavations too. Pulled together, the site tells a clear story of startling technological continuity for nearly 40 thousand years."

The results of this new research at Tiémassas consolidate the sparse record of Middle Stone Age occupations of West Africa. Yet, the site’s location is distinct from others dated to the Middle Stone Age in the region as it is located close to the coast and at the interface of three ecozones: savannahs, forests and mangroves.

"Our new work at Tiémassas offers a neat comparison to recent work on coastal occupations in eastern Africa. They span roughly the same timeframe, have similar ecological characteristics, and are found along tropical coasts," says Blinkhorn. "But the continuity in behaviour we see at Tiémassas stands in stark contrast to the technological changes observed in eastern Africa, and this reflects a similar pattern seen in genetic and palaeoanthropological studies of enduring population structure in West Africa."

As director of fieldwork for the ‘Lise Meitner’ Pan-African Evolution research group’s aWARE project, Blinkhorn is conducting research in Senegal, Ivory Coast, Benin, and Nigeria, looking for connections between the environments of the past and recent human evolution.



Contacts and sources:
Jimbob Blinkhorn
Max Planck Institute for the Science of Human History



Publication: The Middle Stone Age occupations of Tiémassas, coastal West Africa, between 62-25 thousand years ago
Khady Niang, James Blinkhorn, Matar Ndiaye, Mark Bateman, Birame Seck, Gora Sawaré
Journal of Archaeological Science: Reports http://dx.doi.org/10.1016/j.jasrep.2020.102658
Source

Geology at Mars’ Equator Points to Ancient Megaflood



Floods of unimaginable magnitude once washed through Gale Crater on Mars’ equator around 4 billion years ago – a finding that hints at the possibility that life may have existed there, according to data collected by NASA’s Curiosity rover and analyzed in joint project by scientists from Jackson State University, Cornell, the Jet Propulsion Laboratory and the University of Hawaii.

This composite, false-color image of Mount Sharp inside Gale crater on Mars shows geologists a changing planetary environment. On Mars, the sky is not blue, but the image was made to resemble Earth so that scientists could distinguish stratification layers.


Credit: NASA/JPL
 
The research, “Deposits from Giant Floods in Gale Crater and Their Implications for the Climate of Early Mars,” was published Nov. 5 in Nature Scientific Reports.

The raging megaflood – likely touched off by the heat of a meteoritic impact, which unleashed ice stored on the Martian surface – set up gigantic ripples that are tell-tale geologic structures familiar to scientists on Earth.

“We identified megafloods for the first time using detailed sedimentological data observed by the rover Curiosity,” said co-author Alberto G. Fairén, a visiting astrobiologist in the College of Arts and Sciences. “Deposits left behind by megafloods had not been previously identified with orbiter data.”

As is the case on Earth, geological features including the work of water and wind have been frozen in time on Mars for about 4 billion years. These features convey processes that shaped the surface of both planets in the past.

This case includes the occurrence of giant wave-shaped features in sedimentary layers of Gale crater, often called “megaripples” or antidunes that are about 30-feet high and spaced about 450 feet apart, according to lead author Ezat Heydari, a professor of physics at Jackson State University.

The antidunes are indicative of flowing megafloods at the bottom of Mars’ Gale Crater about 4 billion years ago, which are identical to the features formed by melting ice on Earth about 2 million years ago, Heydari said.

The most likely cause of the Mars flooding was the melting of ice from heat generated by a large impact, which released carbon dioxide and methane from the planet’s frozen reservoirs. The water vapor and release of gases combined to produce a short period of warm and wet conditions on the red planet.

Condensation formed water vapor clouds, which in turn created torrential rain, possibly planetwide. That water entered Gale Crater, then combined with water coming down from Mount Sharp (in Gale Crater) to produce gigantic flash floods that deposited the gravel ridges in the Hummocky Plains Unit and the ridge-and-trough band formations in the Striated Unit.

The Curiosity rover science team has already established that Gale Crater once had persistent lakes and streams in the ancient past. These long-lived bodies of water are good indicators that the crater, as well as Mount Sharp within it, were capable of supporting microbial life.

“Early Mars was an extremely active planet from a geological point of view,” Fairén said. “The planet had the conditions needed to support the presence of liquid water on the surface – and on Earth, where there’s water, there’s life.

“So early Mars was a habitable planet,” he said. “Was it inhabited? That’s a question that the next rover Perseverance … will help to answer.”

Perseverance, which launched from Cape Canaveral on July 30, is scheduled to reach Mars on Feb. 18, 2021.

Joining Fairén and Heydari on the paper are Jeffrey F. Schroeder, Fred J. Calef, Jason Van Beek and Timothy J. Parker, of NASA’s Jet Propulsion Laboratory; and Scott K. Rowland, University of Hawaii.

Data and funding were provided by NASA, Malin Space Science Systems, the Jet Propulsion Laboratory and the European Research Council.




Contacts and sources:
Blaine Friedlander
Cornell University
 




Publication: Deposits from giant floods in Gale crater and their implications for the climate of early Mars. E. Heydari, J. F. Schroeder, F. J. Calef, J. Van Beek, S. K. Rowland, T. J. Parker, A. G. Fairén.  Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-75665-7




Saturday, November 21, 2020

Water Has Multiple Liquid States Proved


Water is a ubiquitous liquid with many highly unique properties. The way it responds to changes in pressure and temperature can be completely different from other liquids that we know, and these properties are essential to many practical applications and particularly to life as we know it

What causes these anomalies has long been a source of scientific inspiration with various theoretical explanations, but now an international team of researchers, which includes Nicolas Giovambattista, a professor at The Graduate Center, CUNY and chair for the Department of Physics at Brooklyn College, has proved that water can exist in two different liquid states -- a finding that can explain many of water's anomalous properties. Their research appears in a paper published in the November 20 issue of the journal Science. 

The above graphic offers a conceptual view of how water can exist in two liquid states separated by a thin interface. The bottom liquid is more dense than the one on top, because it is composed of water molecules that are more cosely packed. 
Credit:  Jerker Lokrantz and Anders Nilsson


The possibility that water could exist in two different liquid states was proposed approximately 30 years ago, based on results obtained from computer simulations," Giovambattista said. "This counterintuitive hypothesis has been one of the most important questions in the chemistry and physics of water, and a controversial scenario since its beginnings. This is because experiments that can access the two liquid states in water have been very challenging due to the apparently unavoidable ice formation at the conditions where the two liquids should exist."

The usual "liquid" state of water that we are all familiar with corresponds to liquid water at normal temperatures (approximately 25 centigrade). However, the paper shows that water at low temperatures (approximately -63 centigrade) exists in two different liquid states, a low-density liquid at low pressures and a high-density liquid at high pressures. These two liquids have noticeably different properties and differ by 20% in density. The results imply that at appropriate conditions, water should exist as two immiscible liquids separated by a thin interface similar to the coexistence of oil and water.

Because water is one of the most important substances on Earth -- the solvent of life as we know it -- its phase behavior plays a fundamental role in different fields, including biochemistry, climate, cryopreservation, cryobiology, material science, and in many industrial processes where water acts as a solvent, product, reactant, or impurity. It follows that unusual characteristics in the phase behavior of water, such as the presence of two liquid states, can affect numerous scientific and engineering applications.

"It remains an open question how the presence of two liquids may affect the behavior of aqueous solutions in general, and in particular, how the two liquids may affect biomolecules in aqueous environments," Giovambattista said. "This motivates further studies in the search for potential applications."

Giovambattista is a member of the Physics and Chemistry Ph.D. programs at The Graduate Center of The City University of New York (CUNY).

The international team, led by Anders Nilsson, professor of chemical physics at Stockholm University, used complex experiments and computer simulations to prove this theory. The experiments, described as "science-fiction-like" by Giovambattista, were performed by colleagues at Stockholm University in Sweden, POSTECH University in Korea, PAL-XFEL in Korea, and SLAC national accelerator laboratory in California. The computer simulations were performed by Giovambattista and Peter H. Poole, professor at St. Francis Xavier University in Canada. The computer simulations played an important role in the interpretation of the experiments since these experiments are extremely complex and some observables are not accessible during the experiments.




Contacts and sources:
Shawn Rhea
The Graduate Center of The City University of New York