Tech

LA JOLLA--(March 13, 2020) Just like humans and other animals, plants have hormones. One role of plant hormones is to perceive trouble--whether an insect attack, drought or intense heat or cold--and then signal to the rest of the plant to respond.

A multicenter team led by current and former investigators from the Salk Institute is reporting new details about how plants respond to a hormone called jasmonic acid, or jasmonate. The findings, which were published in Nature Plants on March 13, 2020, reveal a complex communication network. This knowledge could help researchers, such as members of Salk's Harnessing Plants Initiative, develop crops that are hardier and more able to withstand assault, especially in an era of rapid climate change.

"This research gives us a really detailed picture of how this hormone, jasmonic acid, acts at many different levels," says Professor Joseph Ecker, co-corresponding author and Howard Hughes Medical Institute investigator. "It enables us to understand how environmental information and developmental information is processed, and how it ensures proper growth and development."

The plant used in the study was Arabidopsis thaliana, a small flowering plant in the mustard family. Because its genome has been well characterized, this plant is a popular model system. Scientists can take what they learn in A. thaliana and apply it to other plants, including those grown for food. Jasmonic acid is found not only in A. thaliana but throughout the plant kingdom.

"Jasmonic acid is particularly important for a plant's defense response against fungi and insects," says co-first author Mark Zander, a staff researcher in Ecker's lab. "We wanted to precisely understand what happens after jasmonic acid is perceived by the plant. Which genes are activated and deactivated, which proteins are produced and which factors are in control of these well-orchestrated cellular processes?"

The researchers started with plant seeds grown in petri dishes. They kept the seeds in the dark for three days to mimic the first few days of a seed's life, when it is still underground. "We know this growth stage is super important," says co-first author and co-corresponding author Mathew Lewsey, an associate professor at La Trobe University in Melbourne, Australia, who previously worked in Ecker's lab. The first few days in the soil are a challenging time for seedlings, as they face attacks from insects and fungi. "If your seeds don't germinate and successfully emerge from the soil, then you will have no crop," Lewsey adds.

After three days, the plants were exposed to jasmonic acid. The researchers then extracted the DNA and proteins from the plant cells and employed specific antibodies against their proteins of interest to capture the exact genomic location of these regulators. By using various computational approaches, the team was then able to identify genes that are important for the plant's response to jasmonic acid and, moreover, for the cellular cross-communication with other plant hormone pathways.

Two genes that rose to the top in their degree of importance across the system were MYC2 and MYC3. These genes code for proteins that are transcription factors, which means that they regulate the activity of many other genes--or thousands of other genes in this case.

"In the past, the MYC genes and other transcription factors have been studied in a very linear fashion," Lewsey explains. "Scientists look at how one gene is connected to the next gene, and the next one, and so on. This method is inherently slow because there are a lot of genes and lots of connections. What we've done here is to create a framework by which we can analyze many genes at once."

"By deciphering all of these gene networks and subnetworks, it helps us to understand the architecture of the whole system," Zander says. "We now have this very comprehensive picture of which genes are turned on and off during a plant's defense response. With the availability of CRISPR gene editing, these kinds of details can be useful for breeding crops that are able to better withstand attacks from pests."

Another noteworthy aspect of this work is that all of the data from the research has been made available on Salk's website. Researchers can use the site to search for more information about genes they study and find ways to target them.

Silicon photonics is known as a key technology for modern optical communications at the near infrared wavelength-band, i.e., 1.31/1.55 μm. Currently silicon photonics has been desired to be extended to the wavelength-band beyond 1.55 μm, e.g., 2 μm, for important applications in optical communications, nonlinear photonics, and on-chip sensing. However, the realization of high-performance silicon-based waveguide photodetectors beyond 1.55 μm still faces challenges since there are some fabrication issues as well as wavelength-band limitations. As an alternative, two-dimensional materials (e.g., graphene) provide a promising solution because of the ability for broad operation wavelength-bands and the advantage of avoiding structure mismatch in the design and fabrication.

In the paper published in Light: Science & Applications, scientists from Zhejiang University and Southeast University in China proposed and demonstrated high-performance waveguide photodetectors beyond 1.55 μm by introducing a novel silicon-graphene hybrid plasmonic waveguide. In particular, an ultra-thin wide silicon ridge core region with a metal cap atop is introduced to obtain a unique mode field profile, so that light absorption of graphene is enhanced. Furthermore, the fabrication is easy and the graphene-metal contact resistance is reduced, compared to the previous silicon-graphene hybrid waveguides. For example, the graphene absorption efficiencies are as high as 54.3% and 68.6% for 20 μm-long and 50 μm-long absorption regions, when operating at 1.55 μm and 2 μm, respectively.

For the fabricated photodetectors operating at 2 μm, the measured 3 dB-bandwidths are >20 GHz (limited by the experimental setup), while the responsivities are 30-70 mA/W for 0.28 mW input optical power under -0.3V bias voltage. For the photodetectors operating at 1.55 μm, the 3 dB-bandwidth is >40 GHz (limited by the setup), while the measured responsivity is about 0.4 A/W for 0.16 mW input optical power under -0.3V bias voltage.

In this work, the mechanisms in graphene photodetectors are analyzed carefully, which suggested that the photo-thermoelectric effect is the dominant mechanism for photo-response when operating at zero bias voltage. When the photodetector operates at non-zero bias voltages, the dominant mechanism becomes the bolometric or photoconductive effect. This comprehensive analysis helps better understand the photocurrent generation in the graphene-metal interfaces.

These scientists summarize the highlights of their work:

"We have proposed and demonstrated high-performance silicon-graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm. In particular, a novel silicon-graphene hybrid plasmonic waveguide was used by introducing an ultra-thin wide silicon ridge core region with a metal cap atop. The optical modal filed is manipulated in both vertical and horizontal directions. Thus, the light absorption in graphene is enhanced, meanwhile the metal absorption loss is minimized. This greatly helps achieve sufficient light absorption of graphene within a short absorption region."

"The silicon-graphene waveguide photodetectors operating at 2 μm were demonstrated with a 3 dB-bandwidth over 20 GHz. The measured responsivity is 30-70 mA/W at the bias voltage of -0.3V for input optical power of 0.28 mW. The photodetector at 1.55 μm was also demonstrated with excellent performances. The present work paves the way for achieving high-responsivity and high-speed waveguide photodetectors on silicon for near/mid-infrared wavelength-bands" they added.

"In future works, more efforts should be given to introduce some special junction structures to minimize the dark current and further extend the operation wavelength-band. Graphene waveguide photodetectors may play an important role in mid-infrared silicon photonics, which will play an important role in time resolved spectroscopy, lab-on-chip sensing, nonlinear photonics, as well as optical communication" they said.

University of Massachusetts Amherst food scientists produced a lower-salt processed turkey that consumers in a blind sensory test preferred to a full-salt version, according to a study published in the international journal LWT-Food Science and Technology.

"This isn't the holy grail, but it is one strategy that can help reduce salt content in processed foods," says senior author Amanda Kinchla, extension associate professor of food science.

Researchers like Kinchla and her team are constantly looking for ways to reduce sodium in food products because so many health risks are associated with a diet high in sodium, including high blood pressure, stroke, heart disease and kidney problems. Americans typically consume more than half of their calories from ultra-processed food, which is the top source of sodium in the typical diet. Processed deli meats fall into this high-sodium category.

"The U.S. significantly overconsumes sodium from so many places," Kinchla says. "We know this, but we aren't changing. Consumers don't want to buy food with known reduced salt, because they think it's going to taste yucky."

Processed foods are high in sodium because of the sodium diffusion that takes place inside the food during processing. Food product developers have discovered that they can manipulate the size of salt particles and use less if the salt hits the tongue first and lingers. "That is amazing and clever, but it doesn't work with deli meat or foods with a lot of water. The salt will dissolve; you can't keep it on the surface," Kinchla explains.

Under Kinchla's guidance, food science Ph.D. candidate Janam Pandya and undergraduate student Kelsey Decker tested out a novel way to reduce the excessive amount of sodium in processed turkey meat by using different sodium salt species.

The food scientists used turkey breast meat as a protein model to investigate whether limiting the sodium diffusion rates could reduce overall sodium while maintaining a quality of saltiness that consumers accept. To test this out, they incorporated sodium anionic salts, which held a larger structure or molecular weight than sodium chloride, or table salt.

"We processed a portion of turkey breast in traditional sodium chloride [table salt] and in these other salt species and measured a lot of different things: the morphology, texture and the sodium diffusion rate in the meat with different variables, such as processing time, temperature and salt conditions," lead researcher Pandya explains.

The scientists then recruited 46 people on the UMass Amherst campus to participate in a sensory evaluation experiment of three different turkey samples: the control sample with full salt; and two with reduced sodium, one using disodium phosphate and the other a blend of sodium chloride and disodium phosphate.

The overall favorite was the turkey processed with a 50-50 blend of sodium chloride and disodium phosphate. It had 20% less sodium than the full-salt control, compared to 41% less sodium in the disodium phosphate sample. "Sensory results reported that the turkey prepared in a blend of two sodium salts was perceived to be as salty as the control while providing juiciness and texture scores that were preferred over the control," the study states.

Kinchla explains the results: "In our study, the use of sodium salts with a larger molecular structure, such as disodium phosphate, slowed down the overall sodium diffusion rate inside the turkey meat but left enough sodium on the surface of the meat for people to perceive enough saltiness," she says.

The study's "promising results" suggest this is just one of the potentially successful strategies food scientists can pursue to make processed food healthier. "One approach is to find several small ways across the food supply to lower sodium without compromising the quality of the product," Kinchla says.

A Washington State University research team has found that nanoscale particles of the most commonly used plastics tend to move through the water supply, especially in fresh water, or settle out in wastewater treatment plants, where they end up as sludge, in landfills, and often as fertilizer.

Neither scenario is good.

"We are drinking lots of plastics," said Indranil Chowdhury, an assistant professor in WSU's Department of Civil and Environmental Engineering, who led the research. "We are drinking almost a few grams of plastics every month or so. That is concerning because you don't know what will happen after 20 years." 

The researchers, including graduate students, Mehanz Shams and Iftaykhairul Alam, examined what happens to tiny, nanoscale plastics that are making their way into the aquatic environment. They have published their work in the high-impact journal, Water Research.  
 

It's estimated that every day about eight trillion pieces of microplastics go through wastewater treatment plants and end up in the aquatic environment.

These little bits of plastic can come from the degradation of larger plastics or from microbeads that are used in personal care products.

A recent study showed that more than 90 percent of tap water in the U.S. contains nanoscale plastics that are invisible to the human eye, Chowdury said.

In their study, the researchers studied the fate of nanoparticles of polyethylene and polystyrene, which are used in a huge number of products, including plastic bags, personal care products, kitchen appliances, disposable drinking cups and packaging material. They examined how the tiny plastic particles behaved under various chemistries, ranging from salty seawater to water containing organic material. 

"We're looking at this more in a fundamental way," Chowdury said.  "Why are they becoming stable and remaining in the water? Once they're in different types of water, what makes these plastics remain suspended in the environment?"

The researchers found that while acidity of water has little impact on what happens to nanoscale plastics, salt and natural organic matter are important in determining how the plastics move or settle. What is clear is that tiny plastics are staying in the environment with unknown health and environmental consequences, he said.

"Our drinking water plants are not sufficient at removing these micro and nanoscale plastics," he said. "We're finding these plastics in the drinking water but we don't know why." 

Chowdury and his team are now studying techniques for removing the plastics from water and have recently received a grant from the State of Washington Water Research Center for that work.

In the meantime, he encourages people to lessen the impact of nanoscale plastics by reducing their use of single-use plastics. 

"Reuse plastics as much as possible," he said.  

Transmitted by an insect known as the beet leafhopper, curly top disease is a viral disease affecting many crops, including melons, peppers, sugar beets, and tomatoes. Curly top can kill or stunt the plants or result in poorly developed fruit or no fruit at all.

As virus outbreaks are erratic in southern New Mexico and there is no chemical treatment, chile pepper growers have asked for ways to predict when and if they need to be concerned about the disease. Scientists know that the beet leafhopper hosts on the London rocket, a mustard plant, and that greater London rocket abundance in the fall and winter leads to more curly top diseases in crops in the following growing season.

Rebecca Creamer, a plant pathologist at New Mexico State University in Las Cruces, has been working on curly top virus since the mid-1990s. Understanding that London rocket growth and survival is dependent on fall precipitation, Creamer and her colleague Erik Lehnhoff collected fall precipitation data and counted leafhopper numbers on insect traps at numerous New Mexico sites from 2001 to 2018.

"We determined that beet leafhopper numbers in the spring are strongly related to October and November precipitation - more precipitation in these months led to more beet leafhoppers in the spring," said Creamer. "We also discovered that on a farm where good weed control methods mostly removed London rocket through the fall and winter, beet leafhopper numbers were low."

These results will help growers predict future beet leafhopper abundance based on fall precipitation and make informed decisions about weed management and ultimately improve crop yields. "Observations and leafhopper trapping over the years led to hypotheses about the relationships between weed hosts, the leafhoppers, and weather patterns," Creamer adds. "The only real surprise was how well the numbers in the models backed up the hypotheses."

Researchers at University of California San Diego School of Medicine have discovered differences in brain circuitry that contribute to starvation and weight loss in people with anorexia nervosa (AN).

The findings, published in the March 12, 2020 online issue of The American Journal of Psychiatry, shed new light on the neurobiology of starvation and emaciation -- primary characteristics of AN.

"It has long been puzzling how people with anorexia are able to starve themselves and become emaciated, when most people struggle to lose just a few pounds," said Walter Kaye, MD, Distinguished Professor of Psychiatry and executive director of the Eating Disorder Research and Treatment Program at UC San Diego Health. "Because we lack effective treatments that normalize eating in AN, this illness is often chronic and has the highest death rate of any behavioral disorder."

The National Eating Disorders Association estimates that at any given point in time between 0.3 and 0.4 percent of young women and 0.1 percent of young men suffer from AN. A 2007 study found that 0.9 percent of women and 0.3 percent of men reported anorexia during their lives. Young people between the ages of 15 and 24 with AN are estimated to be at 10 times greater risk of dying compared to same-aged peers.

In their latest study, Kaye and colleagues compared brain responses of two groups of female participants who received tastes of sugar water and plain water after either fasting or after a standardized meal. One group of women had been diagnosed with AN, but were in remission (RAN); the other group did not have AN. Neural responses were observed and measured by functional magnetic resonance imaging.

Hunger in people and animals makes food more rewarding because hunger activates brain circuits that motivate eating. The major finding in this study, said Kaye, was that hunger failed to activate this food reward circuit in people with AN, which raises the possibility that the trait underlies restrictive eating and severe weight loss in persons with a history of AN.

Specifically, data showed that the brain's ventral caudal putamen produced varied responses to hunger within the two study groups. RAN participants and the control group both displayed similar responses to food stimulation when sated, but in the RAN group, response to hunger was abnormal. In addition, the RAN group showed reduced neural activation to taste stimulation in the brain's anterior insula and reduced connectivity between the right anterior and mid-dorsal insula and ventral caudal putamen.

"These findings highlight the specific brain circuitry that may play a key role in unhealthy eating in anorexia," said Kaye. "In part, this circuitry involves connected regions that are important for recognizing the feeling of hunger, motivating us to want to eat when we are deprived of food, and helping to initiate actual eating or to decide to avoid it. This same circuitry has been implicated in appetite changes associated with major depression. The distortion of signals in the brain in both depression and anorexia impact the awareness of hunger, the motivation to eat and food avoidance."

Kaye added that the study is the first to show its dysfunction in anorexia after tasting food, specifically after a period of fasting.

Disturbances of this circuitry may help explain symptoms that often occur in anorexia. Most people report that hunger increases the reward and pleasure of food, and thus drives the motivation to eat. Individuals with AN, however, tend to have a disconnect in this process, Kaye said, noting that individuals with the disorder tend to be obsessed with food, yet do not eat.

Study results support the idea that the brain in anorexia is able to recognize hunger signals, but individuals with the disorder may lack an intuitive drive to consume food because they are not able to convert this hunger signal into the motivation to eat.

In addition, many persons with AN describe increased anxiety when they eat, even when they are famished. Researchers found that those with a history of AN associated higher anxiety with a reduced food reward signal in a part of the brain involved in initiating eating behavior. The finding indicates anxiety may contribute to starvation because it impairs the ability to start eating.

The researchers said the findings suggest a powerful biology contributes to restricted eating behavior in AN, and that the findings provide new answers to how those with anorexia are able to become severely underweight.

"These data open the door to potential new ways of treating this disorder," said co-author Christina E. Wierenga, PhD, associate professor and clinical neuropsychologist in the Department of Psychiatry at UC San Diego School of Medicine. "For example, developing behavioral strategies for enhancing initiation to eat or compensating for altered motivational drives may be helpful. In addition, the brain circuitry implicated in these findings have also been highlighted in other studies and support a fresh look at medications acting on the dopamine system."

Fifty years ago, Monty Python's famous sketch, "The Ministry of Silly Walks," first aired on BBC One. The sketch pokes fun at the inefficiency of government bureaucracy. It opens with the Minister (John Cleese) walking in a rather unusual manner to his work, the Ministry of Silly Walks, where Mr. Pudey (Michael Palin) is waiting to meet with him to apply for a government grant to develop his silly walk. In the spirit of Monty Python's humor, based on an actual gait analysis, a Dartmouth research team finds that the Minister's silly walk is 6.7 times more variable than a normal walk. The findings are published in Gait & Posture.

Although Mr. Pudey's walk was found to be only 3.3 times more variable than a normal walk, the research team agreed with the Minister's decision that he had a promising silly walk that was deserving of a Research Fellowship.

The team points out how bureaucratic inefficiency can be likened to that of the peer-review process associated with academic research in the health sciences, particularly when applying for funding. Applying for a federal grant is extremely time consuming and can take months to prepare. An application may require a 150-page proposal followed by a review by a panel of researchers, who are often flown in for the occasion. Peer review protocols often require that the panelists must reach a consensus of 75 percent or more to approve a proposal.

By contrast, the Dartmouth team points out how the National Health and Medical Research Council of Australia pioneered a streamlined grant application process in 2013, which resulted in an estimated savings in 2015 of $A2.1-$4.9 million per year.

"The peer review research process has become rather unwieldy," said Nathaniel J. Dominy, the Charles Hansen Professor of Anthropology, who co-authored the study with Erin E. Butler, who was a postdoctoral fellow at the Neukom Institute at Dartmouth at the time the research was conducted. "If the process was streamlined and grants were awarded more quickly, researchers could start their work earlier, accelerating the timeline for research. Similarly, grant administrators would recoup time and money, which could potentially free up more money for research funding," explained Dominy.

Butler is available for comment at: erin.elizabeth.butler@gmail.com.

Joana Neves is the 2019 grand prize winner of the Sartorius & Science Prize for Regenerating Medicine & Cell Therapy, for work in mice that offers a promising approach to improve the outcome of regenerative stem cell-based therapies aimed at delaying age-related degenerative diseases. The findings help to address a major roadblock imposed by the natural aging processes, which has limited the clinical application of regenerative medicine approaches to treat those most likely to suffer from chronic and often debilitating degenerative conditions - elderly patients. According to Neves, aging is associated with the loss of ability for many tissues to regenerate, largely due to the inflammatory environment common in aged and diseased tissues. Finding a way to resolve chronic inflammation and promote an environment supportive of repair could provide an efficient and effective way to improve the success of stem cell-based therapies. Using the fruit fly Drosphila as a model organism, Neves found that an evolutionarily conserved mechanism of tissue repair - the immune modulatory molecule MANF - could be harnessed to increase the success of regenerative therapies for retinal disease. The protein MAMF is critical in suppressing age-related inflammation while promoting tissue maintenance in young organisms. Using MAMF intervention alongside stem-cell based photoreceptor replacement therapies, Neves was able to greatly improve the restoration of vision in old, blind mice, highlighting the approaches' clinical utility. "[This] work is the proof of principle demonstration that immune modulatory interventions can be effective strategies to improve the success of regenerative therapies applied to aged and diseased organs," said Neves. Finalists for the prize were Arun Sharma, for his essay "Stem cells to help the heart," and Adam Wilkinson, for his essay "Hope for hematological diseases."

AMHERST, Mass. - Ecologists in England and Scotland, collaborating with ecologists Christopher Sutherland and Joseph Drake at the University of Massachusetts Amherst, report this week on a new method of identifying an "entire community of mammals" - including elusive and endangered species that are otherwise difficult to monitor - by collecting DNA from river water.

"Some mammal species are notoriously difficult to monitor," says environmental conservation Ph.D. student Drake. He adds that traditional survey methods are often tailored to a specific species, and therefore don't guarantee the detection of many other important species that are also present. Camera traps have improved the way conservation scientists study wildlife, but environmental DNA (eDNA) methods may offer a monitoring tool that could revolutionize conservation and ecology research, Sutherland adds, but the method required testing.

He adds, "We knew the potential of eDNA was massive, but when it comes to conservation, it is extremely important that we validate new approaches, and that's what we set out to do in this study." Details of their international collaborative work are in the Journal of Applied Ecology.

Naiara Sales of the University of Salford, U.K. and UMass's Drake led this study, in collaboration with researchers from the University of Tromsø, Norway, the universities of Aberdeen, Hull and Sheffield, and Liverpool John Moores University in the U.K. The research takes advantage of the fact that DNA shed from animals, either directly in the water or washed into the river, provides a snapshot of the local mammal community.

Mammologist Allan McDevitt of the University of Salford points out, "We currently use many ways of detecting and monitoring mammals, from looking for signs such as footprints or feces, to using camera traps to take photos of them over several weeks. Now, we may just simply need to collect a few bottles of water and take it to the laboratory and look at the DNA we find."

To test this, the researchers collected water and sediment from streams and rivers in Scotland and England. They found DNA from over 20 wild British mammals and compared the results to historical records, field signs such as fecal samples and cameras. They report that eDNA "provided a similar or better performance in detecting water voles, for example, when compared to looking for water voles using field signs or cameras."

They add that accurately assessing the conservation status and distribution of mammals is increasingly important as many species' populations decline worldwide. Further, surveys using traps, trail cameras and fields signs are time-consuming and costly.

Collaborators for several studies, McDevitt's group, collaborating with Sutherland's group at UMass Amherst, as well as at the universities of Aberdeen and Hull, now believe that using water bodies is an effective way of capturing all the mammals present within a watershed. McDevitt says, "We are always looking for ways to improve biodiversity assessments and monitoring, and we need to find methods which can be applied universally and cost-effectively."

He adds, "We have demonstrated that environmental DNA collected from water bodies is effective for providing us with information about the presence or absence of mammals of conservation concern. This could be used at national levels for monitoring declining or recovering populations, or the early detection of harmful invasive species."

New research from The University of Texas at Austin has explained an important mystery about natural gas hydrate formations and, in doing so, advanced scientists' understanding of how gas hydrates could contribute to climate change and energy security.

The research used a computer model of gas bubbles flowing through hydrate deposits, a common phenomenon which according to existing models, should not be possible based on physics. The new model helps explain how some deposits grow into massive natural gas hydrate reservoirs, such as those found beneath the Gulf of Mexico.

A paper describing the research was published Feb.16, 2020, in the journal Geophysical Research Letters.

Gas hydrates are an icy substance in which gas molecules, typically methane, become trapped in water-ice cages under high pressure and low temperature. They are found widely in nature, house a substantial fraction of the world's organic carbon and could become a future energy resource. However, many questions remain about how hydrate deposits form and evolve.

One such question was raised by observations in the field which spotted methane flowing freely as a gas through hydrate deposits in the subsurface. What puzzled scientists is that under conditions where hydrates occur, methane should only exist as a hydrate, not as a free gas. To solve the mystery of the free flowing gas, a team of UT researchers led by Dylan Meyer, a graduate student at the UT Jackson School of Geosciences, recreated in the lab what they saw in the field.

Using this data, they hypothesized that as hydrate forms in a deposit it also acts as a barrier between gas and water, restricting the speed at which new hydrate forms, and allowing much of the gas to bubble through the deposit. They developed this idea into a computer model and found that the model matched experimental results. When scaled up, they also matched evidence from field studies, making it the first model of the phenomena to successfully do both. Crucially, the model suggests that gas flowing through the subsurface can accumulate into large, concentrated hydrate reservoirs, which could be suitable targets for future energy sources.

"The model convincingly reproduces a range of independent experimental results, which strongly support the fundamental concepts behind it," said Meyer. "We believe this model will be an essential tool for future studies investigating the evolution of large, highly concentrated hydrate reservoirs that experience relatively rapid gas flow through porous media."

The study is the first time this kind of model has been built using data from experiments designed to mimic the gas flow process. The team produced their own hydrate deposit in the lab using a mixture of sand, water and gas and recreating the extreme conditions found in nature. Their efforts provided them with realistic and relevant data from which to develop their model.

Co-author Peter Flemings, a professor at the Jackson School, said that understanding how methane gas travels through hydrate layers in the subsurface is important for understanding methane's role in the carbon cycle and its potential contribution to global warming.

"The paper gives an elegant and simple model to explain some very challenging experiments," said Flemings.

The study's experiments were conducted in specialized labs at the Jackson School, but the
model was the result of a cross-campus collaboration between two UT schools, the Jackson School and the Cockrell School of Engineering.

Meyer, Flemings and Kehua You, a research scientist at the University of Texas Institute for Geophysics (UTIG), had developed the original computer code to explain their experimental results, but it wasn't until they teamed up with David DiCarlo, an associate professor at the the UT Cockrell School of Engineering, who showed them how the results could be presented using analytical math, that they could successfully tackle the problem in a way that mirrored what they were seeing in nature.

The paper is the culmination of Meyer's graduate research and builds on two previously published papers that focused on the results of his lab experiments. Meyer graduated in 2018 with a doctoral degree from the Jackson School and is now a postdoctoral researcher at Academia Sinica in Taipei.

The research was funded by the U.S. Department of Energy (DOE) and is part of a broader partnership between the DOE and The University of Texas at Austin to investigate methane hydrate deposits in the Gulf of Mexico.

Many of the lab experiments that fed into the current study were performed by Meyer at the UT Pressure Core Center, a laboratory at the Jackson School equipped to store and study pressurized cores taken from natural methane hydrate deposits in 2017 and which remains the only such university-based facility.

As oceans absorb more carbon dioxide, they are becoming increasingly acidic and shifting the delicate balance that supports marine life. How species will cope with ocean acidification and the other consequences of global climate change is still very much unknown and could have sweeping consequences.

Researchers from the University of Washington School of Aquatic and Fishery Sciences have discovered that ocean acidification impacts the ability of some oysters to pass down "memories" of environmental trauma to their offspring.

The two papers were published in December in Ecological Applications and the Journal of Shellfish Research.

"Warming and acidifying oceans negatively influence many marine species. However, some species that live in extreme environments, such as the intertidal, may be more resilient than others to these changes," said Laura Spencer, one of the two lead authors and a graduate student in aquatic and fishery sciences. "Some species may even be able to pass on memories of harsh conditions to their offspring, making them more capable of surviving in similarly harsh environments."

Researchers studied two species of ecologically and commercially valuable oysters found throughout Puget Sound: the Olympia oyster and the Pacific oyster. Although oyster larvae are sensitive to acidifying oceans, adult oysters commonly occur in intertidal areas and estuaries where they must endure constantly fluctuating water conditions.

It is this hardiness that has researchers hopeful that oysters can withstand an increasingly acidic ocean. If their resilience to stressors can be passed down to their offspring, it could promote an increased tolerance among the future population.

In Spencer's study, Olympia oysters were exposed to a combination of elevated temperatures and acidified conditions during winter months, mimicking what might happen under climate change. The higher water temperatures caused the oysters to spawn earlier; however, these effects were canceled out when combined with acidified conditions. Researchers then reared and transplanted the exposed oysters' offspring to four estuaries in Puget Sound. They observed that the offspring whose parents were exposed to acidified conditions in the lab had higher survival rates in two of the four bays.

"We found that Olympia oyster adults were relatively resilient to acidification and warming when exposed during the winter," said Spencer. "Most interestingly, we found evidence that adult exposure to acidified conditions can benefit offspring by improving survival."

This carryover effect demonstrates that the experiences of oyster parents have a direct impact on how their offspring perform, and juvenile oysters may be more resilient in certain environments when their parents have been pre-conditioned by similar stressors.

In the other study, adult Pacific oysters were similarly exposed to acidified conditions in the lab. The oysters were then placed back in ambient water to recover before spawning. Researchers observed that the embryonic and larval offspring of female oysters exposed to these experimental conditions experienced poorer survival than a similar control group.

"The conditions one generation of Pacific oysters experience can affect how their children perform," said lead author Yaamini Venkataraman, a graduate student in aquatic and fishery sciences. "Even if oysters are not in stressful conditions when they reproduce, their previous stressful experiences can impact their offspring."

These two contrasting results are both encouraging and concerning to Washington's shellfish industry, which generates nearly $150 million a year and provides over 2,700 jobs. While one study revealed that juvenile Olympia oysters benefited and experienced a survival advantage due to parental exposure to acidified conditions, the other study showed the embryonic and larval survival of Pacific oysters decreased with parental exposure. The authors believe these differing results could be species-specific or because the experiments focused on different life stages of oysters.

Nevertheless, determining how and why some species, such as the Olympia oyster, tolerate ocean acidification and warming helps inform where to focus conservation resources and how to improve growing methods, said Spencer.

"We needed to broaden our understanding of environmental memory when thinking about how oysters or other organisms will persist in the face of climate change," explained Venkataraman. "The aquaculture industry is part of the fiber of Washington, and understanding how oysters will respond to changes in their environment, like more acidic water conditions, across multiple generations is crucial to sustaining the industry."

This recent research shows that as the world's oceans warm and become more acidic due to climate change, species tolerance or sensitivity can't be defined by looking solely at one generation of oysters.

Groups of western gorillas may defend the centres of their home ranges against neighbouring groups, a study in Scientific Reports suggests. These findings may suggest that western gorillas are territorial.

Gorillas are widely assumed to be non-territorial due to their large home ranges (the areas in which they live and move), extensive overlap between the home ranges of different groups, and limited aggression between groups.

Robin Morrison and colleagues used large-scale camera trapping to monitor eight groups of western gorillas (113 individuals in total) across a 60 km2 area in the Republic of Congo. The authors determined the home ranges of each group and found that, although there is some overlap in the home ranges of different groups, gorillas tended to avoid feeding in areas that had been visited by another group that day. Avoidance was more likely the closer the area was to the central region of another group's home range.

The authors suggest that gorillas may avoid the centres of other groups' home ranges to prevent conflict as these regions may be defended by physical aggression or chest beating. They also suggest that larger groups may find it easier to defend central regions than smaller groups.

The findings contribute to a growing body of evidence suggesting that the social structures of gorillas are more complex than previously thought, as interactions between groups are influenced by social and familial relationships and territoriality.

URBANA, Ill. - Like most invasive species, when the soybean aphid arrived in the Midwest in 2000, it brought none of its natural enemies along for the ride. So, naturally, finding itself in the soybean capital of the world, the tiny insect went bonkers. Taking advantage of a nifty ability to reproduce without mating, populations exploded and the soybean aphid quickly became the number one insect pest affecting the crop.

Scientists from the University of Illinois got to work almost immediately to track the pest's movement. They have been collecting soybean aphids throughout the Midwest for the past 18 years, but along the way, they learned a lot more than they expected. In a new report published in American Entomologist, the researchers share their insights.

In 2001, David Voegtlin of the Illinois Natural History Survey set up the first in what would become a regional network of suction traps: PVC pipes extending 20 feet into the air above agricultural fields. Inside, a fan whirls and directs sucked-in insects down into a solution of water and antifreeze, which turns out to be an excellent preservative for bugs, microbes, and genetic material.

For many of the past 18 years, 30-odd traps across the Midwest have been running continuously during daylight hours. And weekly, the contents of the trap are collected and sent to the USDA research lab at the U of I for analysis. That's where Doris Lagos-Kutz comes in.

"There is so much we have learned about the soybean aphid, including spatial and temporal patterns of migration, and about other bugs found in the traps," says Lagos-Kutz, research associate in the USDA Agricultural Research Service and Department of Crop Sciences at the U of I, suction trap analyst, and co-author on the report. "Ultimately, data from the suction traps will help explain the factors that affect insect population dynamics on a continental scale."

Glen Hartman, report co-author and soybean pathologist for the department and USDA-ARS, adds, "The pattern of aphid outbreaks often differs from year to year. By learning where the aphid outbreaks occur, we can associate that back to weather patterns, which could help us project the distribution of these insects under various weather and climate change scenarios."

Because the traps don't discriminate, the scientists have been able to identify many other insects, including some that appear to be expanding their range due to climate change or habitat suitability. For example, in 2015, the traps allowed Lagos-Kutz to detect sugarcane aphid in Kansas and northern Wisconsin for the first time. Detection of the insect, usually only found in southern coastal regions in the U.S., could signal an early threat to sorghum, Miscanthus, and other economically important crops outside the sugarcane growing region.

The traps have also captured cannabis aphids near industrial hemp operations; thrips, which can be vectors for crop-damaging viruses; and mosquitoes, an important vector of human diseases.

Lagos-Kutz notes that the contents of the traps are preserved and available for investigation by other scientists, and hints that there's an untapped mine of information in the collection. "Using next-generation sequencing, we could potentially discover previously unknown organisms in these samples."

Hartman says the traps could also provide information about the air microbiome and air pollutants. "We have a goldmine here. The traps collect all kind of things in the air, inert and biological. Who knows what other biological and chemical entities could be pulled out of these samples?"

The ultimate aim is to find funding and collaborators to spread the suction trap network nationwide, and keep it going indefinitely. There's already a set of traps in the Pacific Northwest, but the two networks aren't formally linked.

"We'd certainly like to have a bigger footprint. This is an extremely valuable source of information that extends well beyond agriculture," Hartman says. "It's the monitor for life in the air."

NASA's Terra satellite passed over the Southern Indian Ocean and provided forecasters with a visible image of Ex-Tropical Cyclone 21S. Although no longer a tropical cyclone, the system has triggered warnings for heavy rainfall and winds.

Tropical cyclone 21S was along the Pilbara coast. The Pilbara Coast is also known as the northwest coast of Western Australia.

The final warning from the Joint Typhoon Warning Center (JTWC) on 21S as a tropical system came on Mar. 11 at 5 p.m. EDT (2100 UTC). At the time, it had maximum sustained winds near 35 knots (64 kph/40 mph) and was moving to the southwest and toward the coast of Western Australia.

On March 12, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA's Terra satellite provided a visible image of 21S that showed the storm affecting the states of Gascoyne and Pilbara. The image showed the low-level circulation center still offshore and the bulk of clouds and precipitation over Western Australia.

The Australian Bureau of Meteorology (ABM) issued warnings. ABM said, "Severe Weather events are forecast to affect Exmouth, Onslow, Barrow Island and Coral Bay. Along the northwest Pilbara coast between Mardie and Coral Bay, sustained gales are possible from late this evening until Friday morning. The weather system may also cause damaging wind gusts to 100 kilometers per hour that could result in damage to homes and property in or near thunderstorms. Heavy rainfall that may lead to flash flooding is possible with isolated falls of 50 to 100mm [`2 to 4 inches]."

At 4:00 p.m. AWST (4 a.m. EST) on Mar. 12, the ABM said ex-tropical cyclone 21S was located about 150 km (93 miles) north of Onslow, moving south southwest. ABM forecasters indicated the low-pressure area is expected to reach the coast later on Thursday or early Friday and may travel parallel to the Gascoyne coast. The tropical low-pressure area is not expected to intensify into a tropical cyclone but is likely to cause a period of heavy rainfall and squally winds.

NASA's Terra satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

For updated forecasts from ABM, visit: http://www.bom.gov.au/

Person-to-person transmission of SARS-CoV-2 occurred between two people with prolonged, unprotected exposure while the first patient was symptomatic. Despite active monitoring and testing of 372 contacts of both cases, no further transmission was detected

New research published in The Lancet, describes in detail the first locally-transmitted case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, in the USA, from a woman who had recently travelled to China and transmitted the infection to her husband. No further transmission was detected, despite monitoring contacts for symptoms and testing all those who developed fever, cough, or shortness of breath, as well as a sample of asymptomatic healthcare professionals who had come into contact with the patients.

On January 23, 2020, Illinois reported the state's first laboratory-confirmed case (index case) of COVID-19 in a woman in her 60s who returned from Wuhan, China in mid-January, 2020. Subsequently, the first evidence of secondary transmission in the USA was reported on January 30, when her husband, who had not travelled outside the USA but had frequent, close contact with his wife since her return, tested positive for SARS-CoV-2.

Public health authorities conducted an intensive epidemiologic investigation of the two confirmed cases. This study describes the clinical and laboratory features of both patients and the assessment and monitoring of several hundred individuals with potential exposure to SARS-CoV-2.

In total, 372 individuals were identified as potential contacts--347 of these people were actively monitored after confirmation of exposure to the woman or her husband on or after the day of symptom onset (including 152 community contacts and 195 healthcare professionals). There were 25 people that had insufficient contact information to complete active monitoring. A convenience sample of 32 asymptomatic healthcare personnel contacts were also tested.

These 347 contacts underwent active symptom monitoring for 14 days following their last exposure. Of these, 43 contacts who developed fever, cough, or shortness of breath were isolated and tested for SARS-CoV-2, as well as asymptomatic healthcare professionals. All 75 individuals tested negative for SARS-CoV-2.

On December 25, 2019, the female patient travelled to Wuhan where she visited a hospitalised relative and other family members with undiagnosed respiratory illness. On her return to the USA on January 13, 2020, she experienced six days of mild fever, fatigue, and cough before being hospitalised with pneumonia and testing positive for SARS-CoV-2 (figure 1). Prior to hospitalisation she was living with her husband who has chronic obstructive pulmonary disease (COPD) and chronic cough. These conditions made it difficult to determine the timing of his symptom onset related to COVID-19. Eight days after his wife was admitted to hospital, the husband was also hospitalised with worsening shortness of breath and coughing up blood, and also tested positive for SARS-CoV-2.

Both patients recovered and were discharged to home isolation, which was lifted 33 days after the woman returned from Wuhan, following two negative tests for SARS-CoV-2 taken 24 hours apart.

"This report suggests that person-to-person transmission of SARS-CoV-2 might be most likely to occur through unprotected, prolonged exposure to an individual with symptomatic COVID-19", says Dr Jennifer Layden, Chief Medical Officer of the Chicago Department of Public Health, USA, who co-led the research. "Our experience of limited transmission of SARS-CoV-2 differs from Wuhan where transmission has been reported to occur across the wider community and among healthcare professionals, and from experiences of other similar coronaviruses. Nevertheless, healthcare facilities should rapidly triage and isolate individuals suspected of having COVID-19, and notify infection prevention services and local health departments for support in testing, management, and containment efforts." [1]

The authors emphasise that individuals who think they might have been exposed to COVID-19 and experiencing a fever, cough, shortness of breath, or other symptoms consistent with COVID-19 should call their healthcare provider before seeking help so that appropriate preventive actions can be taken.

"Although further detailed reports of contact investigations of COVID-19 cases could improve our understanding of the transmissibility of this novel virus, the absence of COVID-19 among healthcare professionals supports US Centers for Disease Control and Prevention (CDC) recommendations around appropriate infection control", explains co-lead author Dr Isaac Ghinai from the Illinois Department of Public Health, USA. [1]

Co-lead author, Dr Tristan McPherson from the Chicago Department of Public Health, USA adds: "Without using appropriate facemasks or other personal protective equipment, individuals living in the same household as, or providing care in a non-healthcare setting for, a person with symptomatic COVID-19 are likely to be at high risk of infection. Current CDC recommendations for individuals with high-risk exposures to remain quarantined with no public activities might be effective in reducing onward person-to-person transmission of SARS-CoV-2." [1]

The researchers acknowledge that these data are preliminary and note several limitations, including that the report describes only one known transmission event, therefore the findings may not be generalisable or representative of broader transmission patterns. They also point out that this investigation might not have identified all individuals with potential exposure to COVID-19 as it was dependent on the couples' recall of the places they visited, the people they met, and the time of symptom onset. Finally, the investigation into these cases took place prior to updated CDC guidance on classifying exposure risk among contacts of patients with COVID-19. For example, updated guidance suggests that a sore throat should be included as a possible symptom of COVID-19 when evaluating healthcare workers, and indicates that a single PCR test, as used in all the contact tracing in this study, might not be sufficient to definitively rule out infection over a 14-day incubation period, and as a result some cases of COVID-19 might not have been detected.