Warbler coloration shaped by evolution via distinct paths

Color-related genes help explain how there are so many species of warblers

PENN STATE

Research News

 

IMAGE: ACCORDING TO A NEW STUDY, THE EVOLUTION OF TWO COLOR RELATED GENES HELPS EXPLAIN THE STRIKING DIVERSITY IN COLORS AND PATTERNS AMONG WOOD WARBLERS, LIKE THE BLACKBURNIAN WARBLER PICTURED HERE. view more 

CREDIT: DARRELL COCHRAN

UNIVERSITY PARK, Pa. -- Two genes that are important for the diverse colors and patterns of warbler plumage have evolved through two very different processes, according to a new study led by Penn State researchers. These evolutionary processes could help explain the rapid evolution of these songbirds into so many unique species.

"Wood warblers are an incredibly colorful and diverse group of birds, with more than a hundred species in total," said Marcella Baiz, postdoctoral researcher at Penn State and first author of the paper. "These species arose very quickly in evolutionary time in what biologists call a species radiation. To better understand this radiation, we studied genetic regions related to plumage coloration within a particularly colorful subset of warblers."

The research team sequenced the genomes of all 34 species within the Setophaga genus of wood warblers and created a phylogenetic tree that clarifies how each species is related to one another. Then, they focused on nine closely related pairs of "sister species." Each pair is the result of one species diverging into two. Seeing if similar evolutionary processes are at play in each of the pairs allowed the researchers to gain a better understanding of the overall radiation.

A paper describing their results appears today (Nov 30.) in the journal Current Biology.

"In most cases it is difficult to get at the genes underlying the diversification process because it can be hard to link specific genes to specific traits, like colors," said David Toews, assistant professor of biology at Penn State and leader of the research team. "But many species of warblers readily interbreed, producing hybrid offspring with a mix of the parent species' traits, so we were previously able to link certain color patterns with their underlying genetic regions. In this study, we focused on two coloration genes, but were able to study them across all the species in this large genus, to give us a window into the rest of the radiation."

The first gene, the Agouti-signaling protein (ASIP), is involved in producing the pigment melanin, which underlies brown and black plumage in these warblers. Within each pair of sister species where there were differences in the amount or location of the black or brown in their plumage, the team predictably found genetic differences near ASIP.

"We created an evolutionary tree based solely on the ASIP gene region, which more clearly shows how the gene has changed across the genus," said Baiz. "The patterns in this gene tree mirror patterns in the phylogenetic tree based on what we see across the whole genome. This implies that the differences we see in ASIP resulted from mutations that arose independently in different species. However, the gene tree from the second gene, BCO2, showed a very different pattern that did not match up with the whole genome tree, which suggests different processes are at play."

The second gene, beta-carotene oxygenate 2 (BCO2), is involved in producing carotenoid pigments, which result in bright yellow, red, and orange plumage. The researchers suggest that a process called introgression-- the exchange of genes between species that have evolved separately--may explain why the pattern of genetic changes in BCO2 didn't align with the overall radiation of the group.

"Introgression can occur when two separate species hybridize, and the hybrid offspring go on to mate with one of the original species," said Baiz. "After several generations, genetic material from one species can be incorporated into the other. The signal of this kind of ancient introgression can be maintained in the genomes of living individuals--like how ancestry tests can reveal how many Neanderthal genes you have. In this instance, we unexpectedly found evidence for ancient introgression at BCO2 in two otherwise distantly related warblers in this genus."

The researchers found evidence of introgression involving the yellow warbler and magnolia warbler and involving the prairie warbler and vitelline warbler, all species with colorful carotenoid coloration in their feathers. However, they note that with the current data it is difficult to tell the directionality of the gene transfer.

"One possibility is that the magnolia warbler version of BCO2 introgressed into the yellow warbler, and this 'new to them' version produced a broader deposition of carotenoids in the feathers of the yellow warbler," said Toews. "It is fun to think that ancient introgression is what made the yellow warbler so yellow!"

This is one of the first examples of carotenoid gene transfer among vertebrates. Collectively, the results of this study suggest that both introgression and a more standard mode of evolution, where mutations occur and are passed from parent to offspring, have played a role in generating the diversity of colors in this genus and could have helped enable the extreme diversification of warblers.

In the future, the researchers hope to link specific mutations in these genes to changes in plumage coloration and to map out the molecular pathways involved in pigment production. They would also like to expand their study to all 110 species of warblers.

"There's a possibility that there may be introgression from another genus entirely," said Toews. "Expanding to other warblers would allow us to explore this possibility, and to more broadly understand the radiation of these fascinating birds."

CAPTION

The research team found that one color-related gene has undergone a standard mode of evolution, with mutations arising in separate species. By contrast, portions of the second gene in some cases have been transferred between species through a process known as introgression, where hybrid birds mate with a parent species and, over generations, transfer genetic material.

CREDIT

Todd Fellenbaum

In addition to Baiz and Toews, the research team includes Andrew Wood, a research technologist at Penn State, Alan Brelsford at the University of California Riverside, and Irby Lovette at the Cornell Lab of Ornithology. The Cornell Lab of Ornithology, the Penn State Eberly College of Science, and the Penn State Huck Institutes of the Life Sciences.

Scientists uncover the mysterious origin of canal grass in Panama

SMITHSONIAN TROPICAL RESEARCH INSTITUTE

Research News

 

IMAGE: BECAUSE ITS TINY SEEDS BLOW IN THE WIND, CANAL GRASS READILY INVADES CLEARINGS AND SPREADS TO FORM IMPENETRABLE STANDS. ITS WHITE FLOWERS AND ITS HISTORICAL ASSOCIATION WITH THE PANAMA CANAL... view more 

CREDIT: KRISTIN SALTONSTALL

Urban legends about the origins of canal grass in Panama abound, but the Smithsonian has new evidence that puts the question to rest. Canal grass is an invasive weed, native to Asia. Because its tiny seeds blow in the wind, it readily invades clearings and spreads to form impenetrable stands by budding from tillers and rhizomes. Once established, canal grass is challenging to eliminate. Fire burns the tops and stimulates the roots. Glassy hairs edging its leaf blades cut skin and dull machetes.

The most widespread story is that the Panama Canal Co. imported canal grass (paja canalera or paja blanca in Spanish, Latin name: Saccharum spontaneum L.) for erosion control. In other versions, the U.S. Army brought it to landscape areas for military exercises or it arrived on ships transiting the canal during the 1950s or 1960s. Another study suggested that seeds or fragments of roots may have washed into the canal from a piece of earth-moving equipment from Thailand or Vietnam shipped through the canal in the 1970s.

"These explanations are all unlikely," said Kristin Saltonstall, STRI staff scientist. "The first documentation of its presence in Panama is a report by the Missouri Botanical Gardens from 1948."

A parent of sugarcane, S. spontaneum often arrives in out-of-the-way places as an escapee from breeding collections. Several previous reports from the Tropical Agriculture and Higher Education Research Center suggested that canal grass escaped from a U.S. Department of Agriculture sugarcane breeding program at the Canal Zone Experimental Gardens (now Summit Nature Park) in the early 1940s. Saltonstall's new genetic results support this idea.

In 1939, the U.S. Department of Agriculture sent more than 500 different varieties of sugarcane and close relatives to the Gardens. Breeders may have been concerned that they could be damaged by hurricanes at the sugarcane experimental station in Canal Point, Florida. The plants were allowed to flower in the gardens as part of ongoing sugarcane breeding trials between 1940 and 1945.

CAPTION

Kristin Saltonstall, STRI staff scientist, is fascinated by large, invasive grass species, which often radically change the ecosystems they invade.

Saltonstall compared DNA extracted from leaves of plants she collected in Panama to DNA samples from a large, international collection of sugarcane and sugarcane relatives maintained by colleagues in Australia, including many of the accessions that were likely brought to Panama in 1939.

"The conditions were right, the plants were there and the timing is right," Saltonstall said. "We can never say with 100% certainty that it came from the Gardens, but it certainly looks like it, because DNA from canal grass in Panama is very similar to accessions from Indonesia in the germplasm collection. All of these plants also have high ploidy levels [many copies of the chromosomes in each cell] and come from the same maternal lineage."

Sugarcane is the world's largest crop. In 2018, Panama produced 2.9 million tons of sugarcane. It was first domesticated in Southeast Asia in the eighth millennium B.C. and gradually spread around the world. Today, a hectare of sugarcane (a cross between S. spontaneum and S. officinarum) yields between 30 and 180 tons of sugar. Sugarcane breeders are eager to improve yield by producing hybrids with other species of grasses, but as they continue to experiment, the possibility of escapes like this continues.

"This was not an intentional introduction," Saltonstall said. "No one was thinking about invasive species at that time. More recently there have been escapes in the U.S. in Florida and Louisiana. Germplasm collections need to be monitored and if there is an escape, it needs to be dealt with before it becomes a problem."

Saltonstall will continue to study canal grass, fascinated by the way these large, invasive plants can take over an area and change its whole ecosystem. And as the world's climate changes, Panama may become drier and more subject to fires, which often start in urban patches of canal grass near burning garbage or roads and then burn into the forest and clear new areas for the canal grass to invade. Canal grass can tolerate drier conditions and outcompete other plants that are not resistant to drought, which may give it an advantage if the climate becomes drier.

CAPTION

Its white flowers and its historical association with the Panama Canal area inspired the common names paja blanca or paja canalera for this sugarcane relative, Saccharum spontaneum L..

CREDIT

Kristin Saltonstall

When businesses behave badly

SINGAPORE MANAGMENT UNIVERSITY

Research News

 

IMAGE: WE'VE ALL HEARD OF CORPORATE SOCIAL RESPONSIBILITY, BUT WHAT HAPPENS WHEN COMPANIES DO THE OPPOSITE? THIS WAS THE QUESTION OF THE HOUR AT THE CONFERENCE ON GREEN AND ETHICAL FINANCE,... view more 

CREDIT: SINGAPORE MANAGEMENT UNIVERSITY

SMU Office of Research & Tech Transfer - On a fateful April night ten years ago, the Deepwater Horizon oil rig exploded - taking the lives of 11 crew members and triggering the largest marine oil spill in history. Nearly five million barrels of oil spilled into the Gulf of Mexico, polluting around 2,100 kilometres of shoreline and killing thousands of marine mammals.

A federal probe later pinned the explosion on cost-cutting measures by British oil supermajor BP, owner of the doomed rig. Not only did BP pay US$20 billion in fines to resolve claims from the catastrophic spill, but the company was also blocked for two years from seeking new contracts with the US government owing to their perceived "lack of business integrity".

However, BP is not the only corporation to have landed in hot water for its lapses in judgment. In 2018, US tech giant Google was hit with a US$1.7 billion fine for stifling competition in online advertising. Such negative incidents resulting from the unscrupulous behaviour of corporations can be considered as instances of corporate social irresponsibility (CSI).

Yet, little research has been done on the impacts of CSI on the corporations themselves. To address this gap in literature, Drs Chloe Ho, Thu Ha Nguyen and Van Vu examined how negative environmental and social-related (E&S) incidents affected corporate policies in a study published in SSRN.

As part of the Conference on Green and Ethical Finance held from 16 to 18 September 2020, their findings were tackled in the environmental, social and governance (ESG) session chaired by Professor Dave Fernandez, Director of Singapore Management University's (SMU) Sim Kee Boon Institute for Financial Economics (SKBI). The virtual conference was jointly organised by SKBI, Asian Development Bank Institute and the Journal of Banking and Finance.

A financial trail of misbehaviour

According to Dr Vu, a Lecturer at La Trobe University who presented the paper on behalf of her co-authors, existing studies tend to focus on corporate social responsibility (CSR), but there is still no consensus on how such activities influence corporate policymaking. This is partly because CSR activities are typically disclosed by firms themselves, making their reports prone to greenwashing biases that distort the company's true impact, said Dr Vu.

This limitation can be overcome by examining negative E&S incidents. As these incidents are 'exogenous shocks' - that is, they are covered by external news reports - focusing on them avoids the problem of firms self-reporting. "Instead of looking at CSR performance, we looked at negative events and asked: what would happen to the firm's activities following these events?" explained Dr Vu.

To answer their primary research question, the authors collected data on E&S incidents dating from 2010 to 2018 and obtained the financial information of the firms involved. They found that following such incidents, the cash holdings, net equity issuances and capital expenditure of firms decrease, while their net debt issuances and leverage increase to buffer the negative shock of the incident.

According to Dr Vu, these findings suggest that firms tend to follow the pecking order theory. This means that after such incidents, firms first draw down on their internal funds to pay penalties and other reputational costs, after which they rely on debt financing rather than equity financing to manage the scandal. Further investigation by the authors also revealed that firms rely more heavily on long-term debt after E&S incidents, due to the liquidity risk posed by short-term debt.

However, companies appear to react differently to the incidents depending on their financial constraints. "Financially constrained firms are unable to raise additional equity in the equity market, which is why they have to cut back on their capital expenditure," Dr Vu said. "This is in contrast to non-financially constrained firms, who tend to be able to rely on the debt market to raise additional funds. This could explain why they don't have to cut back on their investment."

Proving that a little goodwill goes a long way, the authors also observed that firms with a high CSR reputation were more capable of cushioning the impacts of E&S incidents. This was reflected in the fact that firms with high reputational capital do not change their investment and financing decisions compared to low-reputation firms. "CSR is important in a sense that when the firm experiences a negative incident, there are less adverse effects on their business," Dr Vu said.

Zooming out from firm to industry

While the study of Dr Vu and her colleagues certainly addressed a gap in literature, SMU Associate Professor Liang Hao, who was the discussant of the Dr Vu's paper, suggested that their arguments could have been strengthened by the presence of an overarching theory. "We know that CSR affects corporate policies. What's the one story that can expand the results across five dimensions - cash holdings, net equity issuance, capital expenditure, net debt issuance and leverage?" asked Professor Liang.

For instance, CSR could be framed as a risk-management tool. "You do CSR in advance such that after negative shocks, firms and stakeholders will still view you positively and are less likely to punish you," he explained. Alternatively, CSR could also be used as a strategic signalling tool. "Some firms use CSR as a public-relations strategy to signal that they are actually good firms, even though they experience negative shocks." Regardless of which narrative the authors would have chosen, linking the findings to a particular mechanism would have benefitted the paper, Professor Liang said.

Though the authors report on exogenous shocks, Professor Liang argued that E&S incidents are a wider reflection of the firm's corporate governance quality. "There's a high correlation between E&S and governance. This means that well-governed firms have certain patterns of corporate policies," he explained. "What you're probably capturing is a governance effect rather than an E&S effect. Therefore, the results could be driven by poor governance."

Some firm-level E&S incidents may also be emblematic of wider industry-level issues, Professor Liang suggested. Hence, future research could examine the policies of peer firms that did not experience negative shocks following the E&S incidents of other firms. Incidents at the firm level and at the industry level could also be separately analysed, as the latter are considered more exogenous compared to firm-level incidents, Professor Liang noted.

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By Kami Navarro

Flashy lizards are more attractive to mates and to predators

BINGHAMTON UNIVERSITY

Research News

 

IMAGE: A WATER ANOLE WITH A COLORFUL DEWLAP. view more 

CREDIT: J. MONTEMARANO.

BINGHAMTON, NY -- In the lizard world, flashy colors attract the interest of females looking for mates. But they can make colorful males desirable to other eyes, too -- as lunch.

Assistant Research Professor of Biological Sciences Lindsey Swierk is the first author of an article in the journal Evolutionary Ecology on the topic. Called "Intrasexual variability of a conspicuous social signal influences attach rate of lizard models in an experimental test," the article details an experiment involving clay models of water anoles (Anolis aquaticus), a species of lizard only found in Costa Rica and a small slice of Panama. The researchers conducted the experiment at the Las Cruces Biological Station in Costa Rica, which is one of the Organization for Tropical Studies' field stations.

To attract females' notice, male anoles have dewlaps: colorful extendable flaps of skin under their chins. In most species of anole, dewlaps evolved to be as noticeable as possible within the environment, given an environment's predominant colors and lighting conditions.

"Even so, we see a lot of variation within a species in just how bright dewlaps are," Swierk said.

While some water anoles have dramatic red-orange flaps, others have more muted colors, more of a dull brownish-red. Researchers wanted to determine the effect these color variations had on their risk of predation.

While it's widely assumed that flashier males will attract more attention from predators, few studies actually test this assumption. Logistics may be a factor: Researchers have to separate the effects of sexual colors from other aspects of a creature's body and behavior, a difficult task when using real animals. As a result, many studies show correlation but not causation.

To prove that flashier males face greater risks of being attacked, the researchers created clay models with colored dewlaps -- some bright, some more muted. Many visual predators use a stereotyped "search image" to identify prey, so the models only had to approximate anoles' general size, color and shape. The dewlap color, however, required special attention.

"Because different animals have different visual sensitivities than we do as humans, getting the colors right was an important consideration in our model design," Swierk explained. "We ran some pilot trials before this experiment to make sure our models were convincing as 'lizards' -- and they certainly seemed to be, as many birds and other lizards took bites out of them!"

Researchers were able to identity predators from bite marks in the clay models. They included many species of bird, including the strikingly beautiful motmot with its serrated beak. Basilisks and whiptail lizards were also among the likely attackers. The results proved that flashier lizards really do end up as lunch more often.

If bright colors have deadly consequences, why do female anoles prefer them? One answer is that brighter males have either high-quality genetic material or resources that allow them to handle the risk of getting eaten, Swierk explained.

"Because every individual's evolutionary 'mission' in life is to pass on as many copies of its genes as it can, conspicuous traits like these can evolve if they give an individual a high level of reproductive success -- even if the flashy trait ends up killing them in the end," Swierk said.

Tomato's wild ancestor is a genomic reservoir for plant breeders

Humans turned a weedy plant with tiny fruit into the tomato that we know today. That wild ancestor could lead to tomatoes that taste better, are more nutritious and more resilient.

BOYCE THOMPSON INSTITUTE

Research News

 

IMAGE: THE FRUITS OF SOLANUM PIMPINELLIFOLIUM, THE WILD ANCESTOR OF MODERN CULTIVATED TOMATOES, ARE ABOUT THE SIZE OF BLUEBERRIES. view more 

CREDIT: SCOTT PEACOCK AND THE C.M. RICK TOMATO GENETICS RESOURCE CENTER.

ITHACA, NY, December 1, 2020 -- Thousands of years ago, people in South America began domesticating Solanum pimpinellifolium, a weedy plant with small, intensely flavored fruit. Over time, the plant evolved into S. lycopersicum - the modern cultivated tomato.

Although today's tomatoes are larger and easier to farm compared with their wild ancestor, they also are less resistant to disease and environmental stresses like drought and salty soil.

Researchers from Boyce Thompson Institute, led by Zhangjun Fei, created a high-quality reference genome for S. pimpinellifolium and discovered sections of the genome that underlie fruit flavor, size and ripening, stress tolerance and disease resistance. The results were published in Nature Communications on November 16.

"This reference genome will allow researchers and plant breeders to improve traits like fruit quality and stress tolerance in the tomato," said Fei, "for example, by helping them discover new genes in the modern tomato as well as by reintroducing genes from S. pimpinellifolium that were lost over time as S. lycopersicum was domesticated."

Fei is a BTI faculty member and co-corresponding author on the paper, as well as an adjunct professor in Cornell University's School of Integrative Plant Science (SIPS).

Although other groups had previously sequenced S. pimpinellifolium, Fei said this reference genome is more complete and accurate, thanks in part to cutting-edge sequencing technologies that are able to read very long pieces of DNA.

"Older sequencing technologies that read short pieces of DNA can identify mutations at the single-base level," said Shan Wu, a postdoctoral scientist in Fei's lab and co-corresponding author on the paper. "But they aren't good at finding structural variants, like insertions, deletions, inversions or duplications of large chunks of DNA."

"Many known traits of the tomato are caused by structural variants, so that is why we focused on them," Fei said. "Structural variants also are understudied because they are more difficult to identify."

Fei's group compared their S. pimpinellifolium reference genome to that of the cultivated tomato, called Heinz 1706, and found more than 92,000 structural variants.

The researchers then combed the tomato pan-genome, a database with the genomes of more than 725 cultivated and closely related wild tomatoes, and discovered structural variants related to many important traits. For example, the modern cultivated tomato has some genomic deletions that reduce their levels of lycopene, a red pigment with nutritional value, and an insertion that reduces their sucrose content.

Jim Giovannoni, BTI faculty member and co-author of the study, notes that many consumers are disappointed in the quality and flavor of modern production tomatoes because past breeding efforts ignored those traits in favor of performance and yield.

"Identification of the additional genetic diversity captured in the S. pimpinellifolium genome provides breeders with opportunities to bring some of these important features back to store-bought tomatoes," said Giovannoni, who is also an adjunct professor in SIPS and a scientist with the U.S. Department of Agriculture's Agricultural Research Service.

The researchers found many other structural variants that could be of interest to plant breeders, including variants in numerous disease-resistance genes and in genes involved in fruit size, ripening, hormonal regulation, metabolism, and the development of flowers, seeds and leaves.

The group also found structural variants associated with regulating the expression of genes involved in the biosynthesis of lipids in fruit skin, which could help improve the fruit's post-harvest performance.

"So much genetic diversity was lost during tomato domestication," Fei said. "These data could help bring some of that diversity back and result in tomatoes that taste better, are more nutritious and more resilient."

CAPTION

The fruits of Solanum pimpinellifolium, the wild ancestor of modern cultivated tomatoes, are about the size of blueberries.

CREDIT

Scott Peacock and the C.M. Rick Tomato Genetics Resource Center.

Other BTI faculty members who co-authored the paper include Carmen Catalá, who is also an adjunct assistant professor in SIPS, Gregory Martin, who is also a professor in SIPS, and Lukas Mueller, who is also an adjunct professor in SIPS. Susan Strickler, Director of the BTI Computational Biology Center (BCBC), also was a co-author.

The team sequenced the LA2093 accession of S. pimpinellifolium using plant material provided by the C.M. Rick Tomato Genetics Resource Center at the University of California, Davis.

About Boyce Thompson Institute:

Boyce Thompson Institute is a premier life sciences research institution located in Ithaca, New York. BTI scientists conduct investigations into fundamental plant and life sciences research with the goals of increasing food security, improving environmental sustainability in agriculture, and making basic discoveries that will enhance human health. Throughout this work, BTI is committed to inspiring and educating students and to providing advanced training for the next generation of scientists. BTI is an independent nonprofit research institute that is also affiliated with Cornell University. For more information, please visit BTIscience.org

Tweaking carotenoid genes helps 

tomatoes bring their a-game

A research team led by the University of Tsukuba shows that modern gene editing techniques can help tomato breeders introduce diversity and improve the nutrition and environmental impact of tomato crops

UNIVERSITY OF TSUKUBA

Research News

 

IMAGE: TOMATOES USED IN THE EXPERIMENT view more 

CREDIT: UNIVERSITY OF TSUKUBA

Tsukuba, Japan - Cooked, fresh, sun-dried, or juiced, whichever way you prefer them, tomatoes are arguably one of the most versatile fruits on the planet--and yes, despite mainly being used in savory dishes, tomatoes really are a fruit.

The popularity of tomatoes has led to the development of more than 10,000 cultivars of various sizes, shapes, and hues. Interestingly though, there is little genetic diversity among modern tomato varieties. This lack of diversity, coupled with the fact that many traits are controlled by multiple genes, makes improving plant yield and quality a major challenge for tomato breeders.

But in a study published this week in Scientific Reports, researchers led by the University of Tsukuba explain how modern gene editing technology may be able to give tomato breeders a helping hand.

"The tomato was the first genetically modified food to be approved for human consumption," says senior author of the study Professor Hiroshi Ezura. "However, many early transgenic varieties contained genes derived from other species, raising safety concerns among consumers. Therefore, coupled with the fact that most transgenic varieties showed only moderate improvements in quality, tomato breeding has, for the most part, moved away from transgenics."

Unlike traditional genetic modification, modern gene editing techniques leave no trace in the genome and can introduce small changes within a native gene, mimicking natural variation.

Tomatoes contain relatively high levels of carotenoids, the yellow, red, and orange pigments found in many plants. Carotenoids are precursors to vitamin A and demonstrate antioxidant and anti-cancer properties, making them hugely important to human nutrition. Several natural mutations that enhance carotenoid accumulation in tomatoes have been documented, but their introduction into commercial varieties is a complicated and time-consuming prospect.

The University of Tsukuba-led team therefore set about reproducing carotenoid accumulation mutations in tomatoes using gene editing technology.

"Single nucleotide changes in individual tomato genes had previously been achieved using Target-AID gene editing technology," explains Professor Ezura. "However, we designed a system whereby changes were simultaneously introduced into three genes associated with carotenoid accumulation."

Among 12 resulting tomato lines, 10 contained mutations in all three target genes. Further examination of two lines with the dark green fruit and purple roots of natural carotenoid accumulation mutants revealed high levels of carotenoids, particularly lycopene, in the gene-edited plants.

Professor Ezura explains, "This shows that it is possible to improve multigenic plant quality traits using gene editing technology, and opens up a whole range of options for improving the yield, shelf-life, nutrient content, and disease resistance of different crop plants, which has obvious benefits for both human health and the environment."

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Bleach-alternative COVID-19 surface disinfectants may pollute indoor air: USask research

UNIVERSITY OF SASKATCHEWAN

Research News

 

IMAGE: LEFT TO RIGHT, YORK UNIVERSITY CHEMISTRY RESEARCHER CORA YOUNG, USASK CANADA RESEARCH CHAIR TARA KAHAN, SYRACUSE UNIVERSITY POST-DOCTORAL FELLOW SHAN ZHOU MEASURE AIR QUALITY IN A SIMULATED ROOM IN A... view more 

CREDIT: TREVOR VANDENBOER

Cleaning surfaces with hydrogen peroxide-based disinfectants has the potential to pollute the air and pose a health risk, according to research led by University of Saskatchewan (USask).

The research team found that mopping a floor with a commercially available hydrogen peroxide-based disinfectant raised the level of airborne hydrogen peroxide to more than 600 parts per billion--about 60 per cent of the maximum level permitted for exposure over eight hours, and 600 times the level naturally occurring in the air. The results were just published in the journal Environmental Science & Technology.

"When you're washing surfaces, you are also changing the air you are breathing," said USask chemistry researcher Tara Kahan, senior author of the study and Canada Research Chair in Environmental Analytical Chemistry. "Poor indoor air quality is associated with respiratory issues such as asthma."

Too much exposure to hydrogen peroxide could lead to respiratory, skin, and eye irritation, according to the U.S. Centres for Disease Control.

The COVID-19 pandemic has led to increased cleaning and demand for all types of cleaning products, including bleach alternatives that contain hydrogen peroxide.

"At the beginning of the pandemic, we couldn't do research on this topic because hydrogen peroxide solutions were out of stock," Kahan said.

Kahan's team, which also included researchers from Syracuse University, York University (Toronto), and University of York (England), sprayed the vinyl floor in a simulated room environment with 0.88 per cent hydrogen peroxide disinfectant and wiped it dry with paper towel either immediately or after letting it soak in for an hour. The team then tested the air at human head height.

"The real risk is for people who get repeatedly exposed, such as janitors and house cleaners," Kahan said. "We washed the floor and collected measurements at face height--the concentrations will be even stronger at the floor or at the level of a countertop."

Kahan said that the impact on children and pets--those physically closer to the disinfected surfaces--is not yet known.

More than 10 per cent of disinfectants approved by Health Canada that are deemed likely to be effective against SARS-CoV-2 use hydrogen peroxide as the active ingredient. A total of 168 disinfecting products containing hydrogen peroxide as the active ingredient are approved or marketed in Canada.

There are a few ways to reduce risks while disinfecting your home, Kahan says:

• Consider using soap and water instead of a disinfectant--soap and water are known to kill the virus that causes COVID-19.
• Consider opening a window, turning on a range hood, or using your central air system--ventilation can dramatically reduce levels of pollutants circulating in the air and is one of the most effective methods of removing particles that can carry the virus.
• Opt for hydrogen peroxide-based disinfectants over bleach, as Kahan notes "Hydrogen peroxide is still much less potentially harmful than bleach."

Funded by the Canada Research Chairs program and the Alfred P. Sloan Foundation, Kahan's team--mostly women in a discipline which tends to be male-dominated--is currently repeating the experiment in a house and apartment in Saskatoon to determine whether the high numbers occur in a real world environment and to find practical ways to mitigate exposure risks.

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Forearm fractures may signal intimate partner violence

RADIOLOGICAL SOCIETY OF NORTH AMERICA

Research News

 

IMAGE: X-RAY SHOWS FRACTURE TO THE ULNA BONE OF THE FOREARM. view more 

CREDIT: RADIOLOGICAL SOCIETY OF NORTH AMERICA

OAK BROOK, Ill. - Up to one-third of adult women who sustain a non-displaced fracture to the ulna bone of the forearm may be victims of intimate partner violence, according to a study being presented at the annual meeting of the Radiological Society of North America (RSNA). The findings underscore the need to screen for intimate partner violence in women with these types of injuries, researchers said.

Fractures to the ulna, the bone on the pinkie side of the forearm, often occur when people hold up their hands to protect their faces from being struck with an object. These breaks are referred to as "nightstick fractures," because they are frequently seen in people who try to block blows from nightsticks wielded by police officers.

Bharti Khurana, M.D., a radiologist at Brigham and Women's Hospital in Boston and senior author of the study, had observed these fractures in her practice for years, mostly in men. But it was the occasional woman she saw that raised questions.

"I would see these types of injuries in men, but once in a while I would see them in women," Dr. Khurana said. "I never correlated it with intimate partner violence until recently. I shared my thoughts with our orthopedic surgeons and, with their interest and support, decided to pursue the study."

For the study, Dr. Khurana and colleagues searched electronic medical records from six hospitals for isolated ulnar fractures in women ages 18 to 50. They identified 62 patients, average age 31. Of those, 12 were confirmed for intimate partner violence and another eight were suspected of intimate partner violence.

Analysis of the radiographs demonstrated that intimate partner violence was strongly associated with minimally displaced fractures.

"The radiological characteristics we were looking at were the location of the fracture, the pattern of the fracture in terms of how it broke, and the displacement of the fracture," said study lead author David Sing, M.D., an orthopedic surgery resident at Boston Medical Center. "Out of all those things, what we usually saw was a minimally displaced fracture, meaning the bone is broken all the way through but has not shifted significantly."

Confirmed cases were also linked with homelessness and previous visits to the emergency department with musculoskeletal injuries.

Women with ulnar fractures from intimate partner violence who are reluctant to report the crime will often attribute their injuries to a fall, Dr. Khurana said. However, she noted, falls are much more likely to result in a fracture of the radius, the other bone of the forearm.

This observation was supported by the study, as all the patients who were not victims of intimate partner violence had ulnar fractures from motor vehicle accidents or accidental striking, such as from crashing into a tree while skiing. Of the eight patients where intimate partner violence was suspected, four reported a fall.

"It's actually rare to break your ulna in a fall," Dr. Khurana said. "If a radiologist is seeing an ulnar fracture that is non-displaced, and the woman says she had a fall, it's actually quite concerning for intimate partner violence."

The study results suggest that intimate partner violence screening may be underutilized. Formal documentation of intimate partner violence evaluation or screening was completed in only 40% of confirmed/suspected intimate partner violence cases in the study. According to the researchers, radiologists who observe non-displaced ulnar fractures can help close that shortfall by letting the emergency department physician or orthopedic surgeon know that the fracture is often seen in intimate partner violence. The ordering physician can then look at the patient's clinical history to see if there is anything suspicious.

"Careful analysis of previous imaging exams may also help radiologists confirm their suspicion of intimate partner violence," said study co-author Rahul Gujrathi, M.D., a radiology fellow at Brigham and Women's Hospital.

In the study, for instance, historical imaging analysis alone was able to raise suspicion in 75% of clinically confirmed intimate partner violence patients.

"We have resources that we can provide to the patients who are stuck in that situation," Dr. Sing said. "It's especially important during COVID-19, where we've seen the rate of intimate partner violence go up with people trapped at home with their abusers."

Dr. Khurana, who devotes much of her research to identifying radiological signs of intimate partner violence, believes that a more widespread awareness of the association between ulnar fractures and intimate partner violence will help provide earlier detection and intervention.

"The sooner we can address and change the behavior, the better," she said. "Just like radiologists want to diagnose cancer as early as possible, it's the same thing with this. If we diagnose early, we have a better chance to break the cycle of violence."

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This research was partially funded by a Gillian Reny Stepping Strong Innovator Award, Brigham Health. Co-authors are George Dyer, M.D., Mitchel B. Harris, M.D., Camden Bay, Ph.D., Irene Chen, Steven E. Seltzer, M.D., Giles W. Boland M.D., and Paul Tornetta, III, M.D.

For more information and images, visit RSNA.org/press20. Press account required to view embargoed materials.

RSNA is an association of radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Illinois. (RSNA.org)

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Forest fires, cars, power plants join list of risk factors for Alzheimer's disease

Airborne pollution implicated in amyloid plaques, UCSF-led study shows

UNIVERSITY OF CALIFORNIA - SAN FRANCISCO

Research News

 

A new study led by researchers at UC San Francisco has found that among older Americans with cognitive impairment, the greater the air pollution in their neighborhood, the higher the likelihood of amyloid plaques - a hallmark of Alzheimer's disease. The study adds to a body of evidence indicating that pollution from cars, factories, power plants and forest fires joins established dementia risk factors like smoking and diabetes.

In the study, which appears in JAMA Neurology on Nov.30, 2020, the researchers looked at the PET scans of more than 18,000 seniors whose average age was 75. The participants had dementia or mild cognitive impairment and lived in zip codes dotted throughout the nation. The researchers found that those in the most polluted areas had a 10 percent increased probability of a PET scan showing amyloid plaques, compared to those in the least polluted areas.

When applied to the U.S. population, with an estimated 5.8 million people over 65 with Alzheimer's disease, high exposure to microscopic airborne particles may be implicated in tens of thousands of cases.

"This study provides additional evidence to a growing and convergent literature, ranging from animal models to epidemiological studies, that suggests air pollution is a significant risk factor for Alzheimer's disease and dementia," said senior author Gil Rabinovici, MD, of the UCSF Memory and Aging Center, Department of Neurology and the Weill Institute for Neurosciences.

Amyloid Plaques Not Indicative of All Dementias

The 18,178 participants had been recruited for the IDEAS study (Imaging Dementia - Evidence for Amyloid Scanning), which had enrolled Medicare beneficiaries whose mild cognitive impairment or dementia had been diagnosed following comprehensive evaluation. Not all of the participants were later found to have positive PET scans - 40 percent showed no evidence of plaques on the scan, suggesting non-Alzheimer's diagnoses like frontotemporal or vascular dementias, which are not associated with the telltale amyloid plaques.

Air pollution in the neighborhood of each participant was estimated with Environmental Protection Agency data that measured ground-level ozone and PM2.5, atmospheric particulate matter that has a diameter of less than 2.5 micrometers. The researchers also divided locations into quartiles according to the concentration of PM2.5. They found that the probability of a positive PET scan rose progressively as concentrations of pollutants increased, and predicted a difference of 10 percent probability between the least and most polluted areas.

"Exposure in our daily lives to PM2.5, even at levels that would be considered normal, could contribute to induce a chronic inflammatory response," said first author Leonardo Iaccarino, PhD, also of the UCSF Memory and Aging Center, Department of Neurology and the Weill Institute of Neurosciences. "Over time, this could impact brain health in a number of ways, including contributing to an accumulation of amyloid plaques."

Overall concentrations of PM2.5 would not be considered very high for it to have a significant association with amyloid plaques, amounting to annual averages in San Francisco during the study time, added Rabinovici.

"I think it's very appropriate that air pollution has been added to the modifiable risk factors highlighted by the Lancet Commission on dementia," he said, referring to the journal's decision this year to include air pollution, together with excessive alcohol intake and traumatic brain injury, to their list of risk factors.

The study complements previous large-scale studies that tie air pollution to dementia and Parkinson's disease, and adds novel findings by including a cohort with mild cognitive impairment - a frequent precursor to dementia - and using amyloid plaques as a biomarker of disease. Other studies have linked air pollution to adverse effects on cognitive, behavioral and psychomotor development in children, including a UCSF-University of Washington study that looked at its impact on the IQ of the offspring of pregnant women.

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Co-Authors:
Renaud La Joie, PhD, Eunice Lee, PhD, and Isabel Allen, PhD, of UCSF; Orit Lesman-Segev, MD, of UCSF and Sheba Medical Center, Israel; Lucy Hanna and Constantine Gatsonis, PhD, of Brown University School of Public Health; Bruce Hillner, MD, of Virginia Commonwealth University; Barry Siegel, MD, of Washington University School of Medicine; Rachel Whitmer, PhD, of Kaiser Permanente, Oakland, and UC Davis; Maria Carrillo, PhD, of the Alzheimer's Association.

Funding:
The IDEAS study was funded by the Alzheimer's Association, the American College of Radiology, Avid Radiopharmaceuticals, Inc, GE Healthcare and Life Molecular Imaging.

Conflicts of Interest:
Disclosures are listed in the paper in JAMA Neurology.

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