Hexbyte Glen Cove NASA finds 2021 Arctic summer sea ice 12th-lowest on record thumbnail

Hexbyte Glen Cove NASA finds 2021 Arctic summer sea ice 12th-lowest on record

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A still image visualizing Arctic sea ice on Sept. 16, 2021, when the ice appeared to reach its yearly minimum extent. On this date, the extent of the ice was 4.72 million square miles (1.82 million square kilometers). Credit: NASA’s Scientific Visualization Studio

Sea ice in the Arctic appears to have hit its annual minimum extent on Sept. 16, after waning in the 2021 Northern Hemisphere spring and summer. The summertime extent is the 12th-lowest in the satellite record, according to scientists at the NASA-supported National Snow and Ice Data Center and NASA.

This year, the minimum extent of Arctic sea ice dropped to 4.72 million square kilometers (1.82 million square miles). Sea ice extent is defined as the total area in which ice concentration is at least 15%.

The average September minimum extent record shows significant declines since satellites began measuring consistently in 1978. The last 15 years (2007 to 2021) are the lowest 15 minimum extents in the 43-year record.






On Sept. 16, 2021, Arctic sea ice reached its minimum summertime extent. Credit: NASA’s Goddard Space Flight Center/Scientific Visualization Studio

This visualization, created at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, shows data provided by the Japan Aerospace Exploration Agency (JAXA), acquired by the Advanced Microwave Scanning Radiometer 2 (AMSR2) instrument aboard JAXA’s Global Change Observation Mission 1st-Water “SHIZUKU” (GCOM-W1) satellite.



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NASA finds 2021 Arctic summer sea ice 12th-lowest on record (2021, September 22)
retrieved 23 September 2021
from https://phys.org/news/2021-09-nasa-arctic-summer-sea-ice.html

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Hexbyte Glen Cove Seeking climate-smart strategies for root, tuber and banana crops in central Africa thumbnail

Hexbyte Glen Cove Seeking climate-smart strategies for root, tuber and banana crops in central Africa

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Modeling showed an encouraging degree of RT&B resilience to future climates; however, targeted strategies would help ensure that crop suitability remains as robust as projections suggest. Credit: APNI/S. Zingore

Root, tuber and banana (RT&B) crops are widely cultivated across the landscapes of sub-Saharan Africa (SSA). These staple food crops play a fundamental role in smallholder farming systems due to their good economic value and high importance within the daily diets of most households. The extensive planting of RT&B crops highlights their adaptive nature, but a team of researchers has identified a need to obtain more specific knowledge on how RT&B crops might respond to long-term changes in climate. Will this resiliency change? Will growing patterns be drastically altered? Given the importance of RT&B crops, significant shifts in the crop performance as a result of climate-induced changes in suitability would have serious implications for food security across SSA.

Researchers focused their study, recently published in Elsevier’s journal Agricultural Systems, on banana, cassava, , and cropping within the Great Lakes Region (GLR) of Central-East Africa—an area that is bordered by the countries of Burundi, the Democratic Republic of the Congo, Kenya, Malawi, Rwanda, Tanzania, and Uganda. The study was a collaborative effort of modeling and crop scientists representing the International Institute of Tropical Agriculture, International Potato Center, CGIAR Research Program on Climate Change, Agriculture and Food Security, International Livestock Research Institute, CGIAR Research Program on Roots, Tubers and Bananas, Bioversity International, and the African Plant Nutrition Institute.

The study used a crop suitability model that analyzed and mapped crop growth under both a historical climatic baseline and a future projection of average climatic conditions influenced by the impacts of greenhouse gas emissions. Researchers selected a potential climate change scenario following the representative concentration pathway (RCP) 6.0 as reported by the IPCC wherein emissions peak in 2080, and average global temperatures increase between 1.4°C to 3.1°C by 2100.

Results indicate that smallholders within the GLR would generally experience warmer and wetter conditions. This scenario was broadly characterized as being mostly favorable to RT&B cropping systems. Cassava, banana, and sweet potato were found to be most adaptable. In contrast, potato growing areas were much more vulnerable. In fact, widespread reduction in potato crop suitability was projected to generate significant shifts away from traditional areas of production and fewer opportunities for suitable potato cropping alternatives across the GLR.

Adaptation is required

Although modeling showed an encouraging degree of RT&B resilience (with the exception of potato) to future climates, an important aspect of the study dealt with the identification of targeted strategies which, if adopted on a large scale, would help ensure that crop suitability remains as robust as projections suggest. Adaptive measures such as planting date shifting to more advantageous months, and increased use of early maturing or drought/heat-tolerant crop varieties will be critical measures for those areas especially prone to the effects of climate change.

The study indicates that most RT&B (particularly cassava, banana, and sweet potato) are quite flexible in terms of their suitable planting date within the GLR. Flexibility towards alternative planting schedules is an advantage that on the surface favors its adoption by . However, the authors stress that more insight is needed on the current “capacity and willingness” of farmers to make such adaptations. Future efforts require a concerted pursuit of more widespread use of climate-smart RT&B varieties (particularly for potato) that also possess consumer-preferred traits. This will better equip these farmers to deal with future climate-related challenges, especially for those farmers situated in regions subjected to the most intense climatic shifts.

More work is also needed to identify the educational channels and techniques that will be most effective in introducing the adaptive strategies needed within these established but vulnerable production systems.



More information:
Rhys Manners et al, Suitability of root, tuber, and banana crops in Central Africa can be favoured under future climates, Agricultural Systems (2021). DOI: 10.1016/j.agsy.2021.103246

Provided by
African Plant Nutrition Institute

Citation:
Seeking climate-smart strategies for root, tuber and banana crops in central Africa (2021, September 22)
retrieved 23 September 2021
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Hexbyte Glen Cove Hoverflies navigate using sun and body clock thumbnail

Hexbyte Glen Cove Hoverflies navigate using sun and body clock

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A pied hoverfly. Credit: Will Hawkes

Hoverflies use a combination of the sun and their body clock to navigate when they fly south for the winter, new research shows.

The insects keep the sun on their left in the morning, then gradually adjust to maintain a southward route as the day goes on.

Pied and yellow-clubbed hoverflies—which are important pollinators—spend their summers in locations such as the UK and Scandinavia, then fly to the Mediterranean and North Africa in autumn.

These migrations are known to happen on sunny days, but the new study—led by the University of Exeter—is the first proof of a “time-compensated sun compass” in hoverflies.

“Simply flying towards the sun would lead them south, but this would create a winding, inefficient route,” said lead author Richard Massy, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“Our study shows that hoverflies account for the sun’s movement using their circadian rhythm.

“Other animals, including certain birds and butterflies, are known to have this ability. Our work suggests that it has independently evolved across multiple insects.”

Researchers caught migrating hoverflies at a mountain pass in the Pyrenees.

Researchers Rich Massy and Karl Wotton in the field. Credit: Will Hawkes

The insects were placed in a ““, which held them in place but allowed them to swivel freely.

The hoverflies could see the sun but not the ground (meaning they could not navigate using landmarks) and the results showed they headed south by adjusting their course based on the sun’s position and the time of day.

This was further tested by placing some hoverflies in an artificial lighting environment for several days to shift their body clocks, then testing their navigation.

With their circadian rhythm disrupted, their direction of flight shifted westward—supporting the conclusion that they navigate using a time-compensated sun compass.

Dr. Karl Wotton, of the University of Exeter, said: “Understanding how these insects navigate can help us predict their movements.

“This could be useful for , such as limiting the at key migration times.

“Hoverflies are also important predators of crop pests such as aphids, so understanding their migrations could help us use them as natural pest controllers.”

The research team included the University of Bristol, and funding came from the Royal Society and the Natural Environment Research Council’s GW4 Doctoral Training Programme.

The paper, published in the journal Proceedings of the Royal Society B, is entitled: “Hoverflies use a time-compensated to orientate during autumn migration.”



More information:
Hoverflies use a time-compensated sun compass to orientate during autumn migration, Proceedings of the Royal Society B, rspb.royalsocietypublishing.or … .1098/rspb.2021.1805

Citation:
Hoverflies navigate using sun and body clock (2021, September 21)
retrieved 22 September 2021
from https://phys.org/news/2021-09-hoverflies-sun-body-clock.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove How proteins help yeast adapt to changing conditions thumbnail

Hexbyte Glen Cove How proteins help yeast adapt to changing conditions

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Credit: CC0 Public Domain

Proteins in the brain called prions are well known for their involvement in causing disease, but a study published today in eLife suggests they may help yeast cope with rapidly changing environmental conditions.

The findings show that prions may be part of an important epigenetic mechanism for controlling in changing conditions. Further insight into this role could aid our understanding of diseases that involve abnormal cell growth or .

Prions are proteins that are abnormally folded into different shapes. Prions can spread or be passed on to new cells. They have famously been linked to two deadly brain diseases, Creutzfeldt-Jakob and Mad Cow disease. But some prions can be helpful. Each shape of prion may perform a different task in the cell, in a similar way to a Swiss Army knife.

“While scientists have known about prions for decades, we don’t yet know what distinguishes beneficial prions from harmful ones,” says co-first author David Garcia, Ph.D., who was a postdoctoral fellow at the Department of Chemical Systems Biology at Stanford University School of Medicine, California, US, and is now Assistant Professor at the Institute of Molecular Biology, University of Oregon, US.

To learn more, Garcia and colleagues studied a yeast enzyme called pseudouridine synthase that can take on two . They found that, in its alter-ego prion form, this enzyme causes yeast to multiply and grow more quickly, although these changes come at the cost of a shorter lifespan for the yeast.

Through computer modelling, the team then showed that the changes brought about by the prion are beneficial when environmental resources are abundant, but harmful when resources are scarce. By reducing a so-called protein ‘chaperone’, they also showed that the prion can revert to its original enzyme shape. Since protein chaperones themselves fluctuate during changing conditions, they propose that this might be a way to turn the prion on or off when desirable.

“We’ve identified a new role for prions in which they can transform cell growth and survival,” says co-first author Edgar Campbell, a Ph.D. student in Chemical and Systems Biology at Stanford Medicine. “These findings suggest that prions may be another form of epigenetic control of cells.”

Epigenetic changes can alter the behaviour of cells without changing their DNA, can be passed on to new generations of cells, and may be turned on or off by environmental conditions. The authors suggest that learning more about the role of prions in epigenetic control may be critical to improving our understanding of prion diseases.

“These types of epigenetic changes are missed when we sequence genomes but can still have a major influence on cell growth,” concludes senior author Daniel Jarosz, Ph.D., Associate Professor of Chemical and Systems Biology and Developmental Biology at Stanford Medicine. “It is critical to learn more about the consequences of -driven epigenetic changes in and find new ways to search for them in yeast and other organisms.”



More information:
David M Garcia et al, A prion accelerates proliferation at the expense of lifespan, eLife (2021). DOI: 10.7554/eLife.60917

Journal information:
eLife



Citation:
How proteins help yeast adapt to changing conditions (2021, September 21)
retrieved 22 September 2021
from https://phys.org/news/2021-09-proteins-yeast-conditions.html

This do

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Hexbyte Glen Cove Soaring high: Pentagon's Space Force gets new uniform thumbnail

Hexbyte Glen Cove Soaring high: Pentagon’s Space Force gets new uniform

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The US Space Force unveiled its new dress uniform design Tuesday, aiming to make a future-forward mark for the Pentagon’s newest uniformed service.

The prototype for the new uniform for the Space Force’s Guardians, as they have been officially designated, is a short navy blue jacket with a large flap over the right breast, secured by a diagonal line of six silver buttons.

It has a standing collar, and the service badge, with a delta-shaped rocket pushing into a star, is worn below the left breast.

The jacket is matched with grey trousers or skirts.

“Modern, distinctive, professional” the Space Force called it in a tweet.

“Every winning team needs a uniform! We started with the female design and then created the male prototype,” wrote Chief of Space Operations General Jay Raymond.

Tested by Guardians, made for #Guardians. #SpaceForce physical training uniforms are currently undergoing wear testing. pic.twitter.com/6agT93uGDH

— United States Space Force (@SpaceForceDoD) September 20, 2021

Launched officially in December 2019, the Space Force was organized to address challenges of fighting war in the exosphere, seen as a distinct theater from the .

Similar designs with diagonal buttons holding down breast flaps have been seen for centuries in European and American uniforms, and are donned with large amounts of braid by marching band drum majors today.

But the designers for the Space Force seemed aware of the sleeker uniforms seen in “Star Trek”, “Battlestar Galactica”—where uniforms also had the diagonal buttons—and “Star Wars”.

Indeed, the force’s service badge and logo are difficult to distinguish from that of the Starfleet Command from Star Trek.



© 2021 AFP

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Soaring high: Pentagon’s Space Force gets new uniform (2021, September 21)
retrieved 22 September 2021
from https://phys.org/news/2021-09-soaring-high-pentagon-space-uniform.html

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Hexbyte Glen Cove Early long-distance trade links shaped Siberian dogs, study finds thumbnail

Hexbyte Glen Cove Early long-distance trade links shaped Siberian dogs, study finds

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Nenets dogs of the Siberian Arctic resting beside a dogsled in the Iamal-Nenets region of Siberia. Credit: Robert J. Losey.

Archeological finds show that people in the Arctic regions of Northwestern Siberia had already established long-range trading links with Eurasian populations some 2000 years ago. The initiation of trading relationships was one of a series of significant social changes that took place during this period. Moreover, these changes even had an impact on the genomes of Siberian dogs, as an international team of researchers led by LMU palaeogeneticist Laurent Frantz has now demonstrated. Based on extensive genetic analyses, the team concludes that dogs were imported into the Siberian Arctic, and that this process ultimately led to the establishment of Siberian breeds such as the samoyed.

Genomes dating from the Stone Age to the Holocene

The researchers analyzed the genomes of 49 dogs from sites in Siberia and Eurasia dating to between 60 and about 11,000 years ago. Four of the dogs originated from Ust-Polui, where Russian and Canadian archeologists have uncovered the remains of more than 100 dogs dating back to about 2000 years ago. Numerous finds indicate that this site on the remote Yamal peninsula in Northwestern Siberia was in use—most probably for ceremonial purposes—over a period of about 400 years.

“Some of the dogs found there appear to have been intentionally buried,” says Dr. Robert Losey, from the University of Alberta, and lead archeologist of the study. “But there is also evidence which suggests that many were eaten. Dogs were used for a variety of purposes—not only as a means of transport, but potentially also hunting partners and as sources of food.”

The artifacts uncovered in Ust-Polui include glass beads and objects made of metal, which cannot have been fabricated locally. They must have been sourced from the steppe zone, the Black Sea region or the Near East. Therefore, the people who lived on the Yamal peninsula must have been integrated into long-range trading networks more than 2000 years ago. This was also a time of significant social and technological change—as indicated by the exploitation of iron ore and artifacts related to reindeer harnessing both being evidenced at the site. Large-scale reindeer pastoralism, now widely practiced by Indigenous people in this region, emerged here only in the last few centuries.

Dogs as trade goods

The new genetic analyses revealed that dogs were also among the goods imported into the Siberian Arctic imported from areas further to the south at this time. “Whereas Arctic dogs evolved in isolation prior to at least 7000 years ago, genomic DNA isolated from Siberian dogs dated to between the Iron Age and medieval times shows that there were increasing portions of genetic material derived from dogs from the Eurasian steppes, as well as Europe,” says Dr. Tatiana Feuerborn, the lead author on the paper based at the University of Copenhagen. Thus, the proportion of non-Siberian ancestry among dogs on the Yamal peninsula increased significantly during this period. “Dogs were potentially valuable possessions, and they were bought and sold,” says Frantz. On the other hand, human genomes in Arctic Siberia remained quite stable over this long stretch of time, and there is little sign of genetic input from non-Arctic populations.

The authors of the new study assume that the import of dogs from farther afield is a reflection of societal transitions in Siberia. “The first dogs domesticated in the Arctic served primarily as sledding dogs,” says Frantz. “When Siberian populations turned to pastoralism, they may well have required dogs that had other useful behavioral traits, which were better suited for reindeer herding. The mixing of Arctic dogs with other populations potentially led to the establishment of dog lineages that were both suited to herding and also adapted to the harsh climatic conditions.”

From working dog to samoyed

This strategy of cross-breeding and selection for improved traits eventually led to the emergence of modern Siberian canine lineages such as the samoyed. “A large fraction of the samoyed genome can be traced back to ancestral Arctic bloodlines,” says Frantz, “but it also shows far more Western influence than the husky, for instance.” Because very little subsequent hybridization with other breeds has occurred in the meantime, yet samoyeds have remained largely unchanged since the Middle Ages. In contrast, most other modern breeds result from the targeted efforts of breeders during the 19th and 20th centuries. Only when polar explorers such as Ernest Shackleton obtained dogs from the Arctic and began to breed from them did the samoyed acquire its modern name. “Prior to that they were simply a population of working ,” says Frantz.

The study is published in the Proceedings of the National Academy of Sciences.



More information:
Modern Siberian dog ancestry was shaped by several thousand years of Eurasian-wide trade and human dispersal, Proceedings of the National Academy of Sciences, 2021. www.pnas.org/cgi/doi/10.1073/pnas.2100338118

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Hexbyte Glen Cove Solar electric propulsion makes NASA's Psyche spacecraft go thumbnail

Hexbyte Glen Cove Solar electric propulsion makes NASA’s Psyche spacecraft go

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NASA’s Psyche spacecraft is photographed in July 2021 during the mission’s assembly, test, and launch operations phase at JPL. Hall thrusters will propel the spececraft to its target in the main asteroid belt. Credit: NASA/JPL-Caltech

When it comes time for NASA’s Psyche spacecraft to power itself through deep space, it’ll be more brain than brawn that does the work. Once the stuff of science fiction, the efficient and quiet power of electric propulsion will provide the force that propels the Psyche spacecraft all the way to the main asteroid belt between Mars and Jupiter. The orbiter’s target: A metal-rich asteroid also called Psyche.

The will launch in August 2022 and travel about 1.5 billion miles (2.4 billion kilometers) over three and a half years to get to the asteroid, which scientists believe may be part of the core of a planetesimal, the building block of an early rocky planet. Once in orbit, the mission team will use the payload of science instruments to investigate what this unique target can reveal about the formation of rocky planets like Earth.

The spacecraft will rely on the large chemical rocket engines of the Falcon Heavy launch vehicle to blast off the launchpad and to escape Earth’s gravity. But the rest of the journey, once Psyche separates from the launch vehicle, will rely on solar electric propulsion. This form of propulsion starts with large solar arrays that convert sunlight into electricity, providing the power source for the spacecraft’s thrusters. They’re known as Hall thrusters, and the Psyche spacecraft will be the first to use them beyond the orbit of our moon.

At left, xenon plasma emits a blue glow from an electric Hall thruster identical to those that will propel NASA’s Psyche spacecraft to the main asteroid belt. On the right is a similar non-operating thruster. Credit: NASA/JPL-Caltech

For propellant, Psyche will carry tanks full of xenon, the same neutral gas used in car headlights and plasma TVs. The spacecraft’s four thrusters will use electromagnetic fields to accelerate and expel charged atoms, or ions, of that xenon. As those ions are expelled, they create thrust that gently propels Psyche through space, emitting blue beams of ionized xenon.

In fact, the thrust is so gentle, it exerts about the same amount of pressure you’d feel holding three quarters in your hand. But it’s enough to accelerate Psyche through deep space. With no atmospheric drag to hold it back, the spacecraft eventually will accelerate to speeds of up to 200,000 miles per hour (320,000 kilometers per hour).

Because they’re so efficient, Psyche’s Hall thrusters could operate nearly nonstop for years without running out of fuel. Psyche will carry 2,030 pounds (922 kilograms) of xenon in its tanks; engineers estimate that the mission would burn through about five times that amount of propellant if it had to use traditional chemical thrusters.

“Even in the beginning, when we were first designing the mission in 2012, we were talking about solar electric propulsion as part of the plan. Without it, we wouldn’t have the Psyche mission,” said Arizona State University’s Lindy Elkins-Tanton, who as principal investigator leads the mission. “And it’s become part of the character of the mission. It takes a specialized team to calculate trajectories and orbits using solar electric propulsion.”

A gentle maneuver

Psyche will launch from the historic Pad 39A at NASA’s Kennedy Space Center. The Falcon Heavy will place the spacecraft on a trajectory to fly by Mars for a gravity assist seven months later, in May 2023. In early 2026, the thrusters will do the delicate work of getting the spacecraft into orbit around asteroid Psyche, using a bit of ballet to back into orbit around its target.

That task will be especially tricky because of how little scientists know about the asteroid, which appears as only a tiny dot of light in telescopes. Ground-based radar suggests it’s about 140 miles (226 kilometers) wide and potato-shaped, which means that scientists won’t know until they get there how exactly its gravity field works. As the mission conducts its science investigation over 21 months, navigation engineers will use the electric propulsion thrusters to fly the spacecraft through a progression of orbits that gradually bring the spacecraft closer and closer to Psyche.

NASA’s Jet Propulsion Laboratory in Southern California, which manages the mission, used a similar propulsion system with the agency’s Deep Space 1, which launched in 1998 and flew by an asteroid and a comet before the mission ended in 2001. Next came Dawn, which used solar electric propulsion to travel to and orbit the Vesta and then the protoplanet Ceres. The first spacecraft ever to orbit two extraterrestrial targets, the Dawn mission lasted 11 years, ending in 2018 when it used up the last of the hydrazine propellant used to maintain its orientation.

Partners in propulsion

Maxar Technologies has been using solar electric propulsion to power commercial communications satellites for decades. But for Psyche, they needed to adapt the superefficient Hall thrusters to fly in deep space, and that’s where JPL engineers came in. Both teams hope that Psyche, by using Hall thrusters for the first time beyond lunar orbit, will help push the limits of solar electric propulsion.

“Solar technology delivers the right mix of cost savings, efficiency, and power and could play an important role in supporting future science missions to Mars and beyond,” said Steven Scott, Maxar’s Psyche program manager.

Along with supplying the thrusters, Maxar’s team in Palo Alto, California, was responsible for building the spacecraft’s van-size chassis, which houses the electrical system, the propulsion systems, the thermal system, and the guidance and navigation system. When fully assembled, Psyche will move into JPL’s huge thermal vacuum chamber for testing that simulates the environment of deep space. By next spring, the spacecraft will ship from JPL to Cape Canaveral for launch.



More information:
For more information about NASA’s Psyche mission, go to:

www.nasa.gov/psyche

psyche.asu.edu/

Citation:
Solar electric propulsion makes NASA’s Psyche spacecraft go (2021, September 20)
retrieved 21 September 2021
from https://phys.org/news/2021-09-solar-electric-propulsion-nasa-psyche.html

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Hexbyte Glen Cove RNA-targeting enzyme expands the CRISPR toolkit thumbnail

Hexbyte Glen Cove RNA-targeting enzyme expands the CRISPR toolkit

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McGovern Fellows Jonathan Gootenberg (left) and Omar Abudayyeh in their lab. Credit: Caitlin Cunningham

Researchers at MIT’s McGovern Institute for Brain Research have discovered a bacterial enzyme that they say could expand scientists’ CRISPR toolkit, making it easy to cut and edit RNA with the kind of precision that, until now, has only been available for DNA editing. The enzyme, called Cas7-11, modifies RNA targets without harming cells, suggesting that in addition to being a valuable research tool, it provides a fertile platform for therapeutic applications.

“This new is like the Cas9 of RNA,” says McGovern Fellow Omar Abudayyeh, referring to the DNA-cutting CRISPR enzyme that has revolutionized modern biology by making DNA editing fast, inexpensive, and exact. “It creates two precise cuts and doesn’t destroy the cell in the process, like other enzymes,” he adds.

Up until now, only one other family of RNA-targeting enzymes, Cas13, has extensively been developed for RNA targeting applications. However, when Cas13 recognizes its target, it shreds any RNAs in the cell, destroying the cell along the way. Like Cas9, Cas7-11 is part of a programmable system; it can be directed at specific RNA targets using a CRISPR guide. Abudayyeh, McGovern Fellow Jonathan Gootenberg, and their colleagues discovered Cas7-11 through a deep exploration of the CRISPR systems found in the microbial world. Their findings were recently reported in the journal Nature.

Exploring natural diversity

Like other CRISPR proteins, Cas7-11 is used by bacteria as a defense mechanism against viruses. After encountering a new virus, bacteria that employ the CRISPR system keep a record of the infection in the form of a small snippet of the pathogen’s . Should that virus reappear, the CRISPR system is activated, guided by a small piece of RNA to destroy the viral genome and eliminate the infection.

These ancient immune systems are widespread and diverse, with different bacteria deploying different proteins to counter their viral invaders.

“Some target DNA, some target RNA. Some are very efficient in cleaving the target but have some toxicity, and others do not. They introduce different types of cuts, they can differ in specificity—and so on,” says Eugene Koonin, an evolutionary biologist at the National Center for Biotechnology Information.

Abudayyeh, Gootenberg, and Koonin have been scouring genome sequences to learn about the natural diversity of CRISPR systems—and to mine them for potential tools. The idea, Abudayyeh says, is to take advantage of the work that evolution has already done in engineering machines.

“We don’t know what we’ll find,” Abudayyeh says, “but let’s just explore and see what’s out there.”

As the team was poring through public databases to examine the components of different bacterial defense systems, a protein from a bacterium that had been isolated from Tokyo Bay caught their attention. Its amino acid sequence indicated that it belonged to a class of CRISPR systems that use large, multiprotein machines to find and cleave their targets. But this protein appeared to have everything it needed to carry out the job on its own. Other known single-protein Cas enzymes, including the Cas9 protein that has been widely adopted for DNA editing, belong to a separate class of CRISPR systems—but Cas7-11 blurs the boundaries of the CRISPR classification system, Koonin says.

The enzyme, which the team eventually named Cas7-11, was attractive from an engineering perspective, because single proteins are easier to deliver to cells and make better tools than their complex counterparts. But its composition also signaled an unexpected evolutionary history. The team found evidence that through evolution, the components of a more complex Cas machine had fused together to make the Cas7-11 protein. Gootenberg equates this to discovering a bat when you had previously assumed that birds are the only animals that fly, thereby recognizing that there are multiple evolutionary paths to flight. “It totally changes the landscape of how these systems are thought about, both functionally and evolutionarily,” he says.

Precision editing

When Gootenberg and Abudayyeh produced the Cas7-11 protein in their lab and began experimenting with it, they realized this unusual enzyme offered a powerful means to manipulate and study RNA. When they introduced it into cells along with an RNA guide, it made remarkably precise cuts, snipping its targets while leaving other RNA undisturbed. This meant they could use Cas7-11 to change specific letters in the RNA code, correcting errors introduced by genetic mutations. They were also able to program Cas7-11 to either stabilize or destroy particular RNA molecules inside cells, which gave them the ability to adjust the levels of the proteins encoded by those RNAs.

Abudayyeh and Gootenberg also found that Cas7-11’s ability to cut RNA could be dampened by a protein that appeared likely to also be involved in triggering programmed cell death, suggesting a possible link between CRISPR defense and a more extreme response to infection.

The team showed that a gene therapy vector can deliver the complete Cas7-11 editing system to cells and that Cas7-11 does not compromise cells’ health. They hope that with further development, the enzyme might one day be used to edit disease-causing sequences out of a patient’s RNA so their cells can produce healthy proteins, or to dial down the level of a protein that is doing harm due to genetic disease.

“We think that the unique way that Cas7-11 cuts enables many interesting and diverse applications,” Gootenberg says, noting that no other CRISPR tool cuts RNA so precisely. “It’s yet another great example of how these basic-biology driven explorations can yield new tools for therapeutics and diagnostics,” he adds. “And we’re certainly still just scratching the surface of what’s out there in natural diversity.”



More information:
Ahsen Özcan et al, Programmable RNA targeting with the single-protein CRISPR effector Cas7-11, Nature (2021). DOI: 10.1038/s41586-021-03886-5

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Hexbyte Glen Cove Faroe Islands mass dolphin slaughter casts shadow over tradition thumbnail

Hexbyte Glen Cove Faroe Islands mass dolphin slaughter casts shadow over tradition

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The ‘grind’ hunt in Torshavn, Faroe Islands, on May 29, 2019.

Every summer in the Faroe Islands hundreds of pilot whales and dolphins are slaughtered in drive hunts known as the “grind” that residents defend as a long-held tradition.

The hunt always sparks fierce criticism abroad, but never so much as last week when a particularly bountiful catch saw 1,428 dolphins massacred in one day, raising questions on the island itself about a practice that activists have long deemed cruel.

Images of hundreds upon hundreds of dolphins lined up on the sand, some of them hacked up by what appeared to be propellers, the water red with blood, shocked some of the staunchest supporters of the “grind” and raised concern in the archipelago’s crucial fishing industry.

For the first time, the local government of the autonomous Danish archipelago located in the depths of the North Atlantic said it would re-evaluate regulations surrounding the killing of dolphins specifically, without considering an outright ban on the tradition.

“I had never seen anything like it before. This is the biggest catch in the Faroes,” Jens Mortan Rasmussen, one of the hunter-fishermen present at the scene in the village of Skala, told AFP.

Open-air slaughterhouse

While used to criticism, he said this time round it was “a little different”.

“Fish exporters are getting quite a lot of furious phone calls from their clients and the salmon industry has NOW mobilised against dolphin-hunting. It’s a first.”

The meat of pilot whales and dolphins is only eaten by the fishermen themselves, but there is concern that news of the massacre will hit the reputation of an archipelago that relies considerably on exporting other fish including salmon.

Traditionally, the Faroe Islands —which have a population of 50,000—hunt pilot whales in a practice known as “grindadrap,” or the “grind.”

Hunters first surround the whales with a wide semi-circle of fishing boats and then drive them into a bay to be beached and slaughtered by fishermen on the beach.

Normally, around 600 pilot whales are hunted every year in this way, while fewer dolphins also get caught.

Defending the hunt, the Faroese point to the abundance of whales, dolphins, and porpoises in their waters (over 100,000, or two per capita).

They see it as an open-air slaughterhouse that isn’t that different to the millions of animals killed behind closed doors all over the world, said Vincent Kelner, the director of a documentary on the “grind”.

And it’s of historical significance for the Faroe Islanders: without this meat from the sea, their people would have disappeared.

The people of Torshavn have long defended the Faroe Islands summer tradition of hunting pilot whales and dolphins.

‘Overwhelmed’

But still, on September 12, the magnitude of the catch in the large fjord came as a shock as fishermen targeted a particularly big school of dolphins.

The sheer number of the mammals that beached slowed down the slaughter which “lasted a lot longer than a normal grind”, said Rasmussen.

“When the dolphins reach the beach, it’s very difficult to send them back to sea, they tend to always return to the beach.”

Kelner said the fishermen were “overwhelmed”.

“It hits their pride because it questions the professionalism they wanted to put in place,” he added.

While defending the practice as sustainable, Bardur a Steig Nielsen, the archipelago’s prime minister, said Thursday the government would re-evaluate “dolphin hunts, and what part they should play in Faroese society.”

Critics say that the Faroese can no longer put forward the argument of sustenance when killing and dolphins.

“For such a hunt to take place in 2021 in a very wealthy European island community… with no need or use for such a vast quantity of contaminated meat is outrageous,” said Rob Read, at marine conservation NGO Sea Shepherd, referring to high levels of mercury in dolphin meat.

The NGO claims the hunt also broke several laws.

“The Grind foreman for the district was never informed and therefore never authorised the hunt,” it said in a statement.

It also claims that many participants had no licence, “which is required in the Faroe Islands, since it involves specific training in how to quickly kill the and dolphins.”

And “photos show many of the dolphins had been run over by motorboats, essentially hacked by propellers, which would have resulted in a slow and painful death.”

Faroese journalist Hallur av Rana said that while a large majority of islanders defend the “grind” itself, 53 percent are opposed to killing .



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Hexbyte Glen Cove The nanophotonics orchestra presents: Twisting to the light of nanoparticles thumbnail

Hexbyte Glen Cove The nanophotonics orchestra presents: Twisting to the light of nanoparticles

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Upon illumination with red light, third harmonic scattered light (in violet) reveals the twist of metal nanoparticles. Credit: Ventsislav Valev and Lukas Ohnoutek

Physics researchers at the University of Bath in the UK discover a new physical effect relating to the interactions between light and twisted materials—an effect that is likely to have implications for emerging new nanotechnologies in communications, nanorobotics and ultra-thin optical components.

In the 17th and 18th centuries, the Italian master craftsman Antonio Stradivari produced musical instruments of legendary quality, and most famous are his (so-called) Stradivarius violins. What makes the musical output of these musical instruments both beautiful and unique is their particular timbre, also known as tone color or tone quality. All instruments have a timbre—when a musical note (sound with frequency fs) is played, the instrument creates harmonics (frequencies that are an integer multiple of the initial frequency, i.e. 2fs, 3fs, 4fs, 5fs, 6fs, etc.).

Similarly, when of a certain color (with frequency fc) shines on materials, these materials can produce harmonics (light frequencies 2fc, 3fc, 4fc, 5fc, 6fc, etc.). The harmonics of light reveal intricate material properties that find applications in medical imaging, communications and .

For instance, virtually every green laser pointer is in fact an infrared laser pointer whose light is invisible to human eyes. The green light that we see is actually the second harmonic (2fc) of the infrared laser pointer and it is produced by a special crystal inside the pointer.

In both musical instruments and shiny materials, some frequencies are ‘forbidden’ – that is, they cannot be heard or seen because the instrument or material actively cancels them. Because the clarinet has a straight, cylindrical shape, it supresses all of the even harmonics (2fs, 4fs, 6fs, etc.) and produces only odd harmonics (3fs, 5fs, 7fs, etc.). By contrast, a saxophone has a conical and curved shape which allows all harmonics and results in a richer, smoother sound. Somewhat similarly, when a specific type of light (circularly polarized) shines on metal nanoparticles dispersed in a liquid, the odd harmonics of light cannot propagate along the direction of light travel and the corresponding colors are forbidden.

Now, an international team of scientists led by researchers from the Department of Physics at the University of Bath have found a way to reveal the forbidden colors, amounting to the discovery of a new physical effect. To achieve this result, they ‘curved’ their experimental equipment.

Professor Ventsislav Valev, who led the research, said: “The idea that the twist of nanoparticles or molecules could be revealed through even harmonics of light was first formulated over 42 years ago, by a young Ph.D. student—David Andrews. David thought his theory was too elusive to ever be validated experimentally but, two years ago, we demonstrated this phenomenon. Now, we discovered that the twist of nanoparticles can be observed in the odd harmonics of light as well. It’s especially gratifying that the relevant theory was provided by none other than our co-author and nowadays well-established professor—David Andrews!

“To take a musical analogy, until now, scientists who study twisted molecules (DNA, amino acids, proteins, sugars, etc) and nanoparticles in water—the element of life—have illuminated them at a given frequency and have either observed that same or its noise (inharmonic partial overtones). Our study opens up the study of the harmonic signatures of these twisted molecules. So, we can appreciate their ‘timbre’ for the first time.

“From a practical point of view, our results offer a straightforward, user-friendly experimental method to achieve an unprecedented understanding of the interactions between light and twisted materials. Such interactions are at the heart of emerging new nanotechnologies in communications, nanorobotics and ultra-thin optical components. For instance, the ‘twist’ of nanoparticles can determine the value of information bits (for left-handed or right-handed twist). It is also present in the propellers for nanorobots and can affect the direction of propagation for a laser beam. Moreover, our method is applicable in tiny volumes of illumination, suitable for the analysis of natural chemical products that are promising for new pharmaceuticals but where the available material is often scarce.

Ph.D. student Lukas Ohnoutek, also involved in the research, said: “We came very close to missing this discovery. Our initial equipment was not ‘tuned’ well and so we kept seeing nothing at the third-. I was starting to lose hope but we had a meeting, identified potential issues and investigated them systematically until we discovered the problem. It is wonderful to experience the at work, especially when it leads to a scientific discovery!”

Professor Andrews added: ”Professor Valev has led an international team to a real first in the applied photonics. When he invited my participation, it led me back to theory work from my doctoral studies. It has been amazing to see it come to fruition so many years later.”

The research is published in the journal Laser & Photonic Reviews.



More information:
Lukas Ohnoutek et al, Optical Activity in Third‐Harmonic Rayleigh Scattering: A New Route for Measuring Chirality, Laser & Photonics Reviews (2021). DOI: 10.1002/lpor.202100235

Citation:

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