OREGON STATE UNIVERSITY

college of agricultural sciences

Scientists name new species of fish from the Orinoco region after singer Enya

CORVALLIS, Ore. – In 1988, Irish singer and songwriter Enya released a lead single titled “Orinoco Flow” from her second studio album, which went on to become an international hit, earn a Grammy Award nomination, and help launch her wildly successful career.

Now a team of scientists have named a new species of fish from the Orinoco River drainage after her.

Leporinus enyae is a “beautiful little fish,” said Michael Burns, a doctoral candidate at Oregon State University and lead author on the paper describing the new species, as well another from the Xingu River of Brazil. It was published this week in the journal Neotropical Ichthyology by researchers from Oregon State and Brazil.

“Whenever we were in the lab at Oregon State working on the fishes, Ben Frable would always play ‘Orinoco Flow,” said Burns, referring to another graduate student in the lab.

“I heard the song so often in the lab it got stuck in my head,” co-author Marcus Chatfield said. “Then I just started listening to it on purpose when I was taking measurements of the specimens. When the time came around for choosing names, it just felt right to name this new beautiful fish from the Orinoco after the artist who wrote that beautiful song.”

“We’re also big fans of her music,” added co-author Brian Sidlauskas, the curator of fishes at Oregon State University as well as an amateur Celtic harper.

The second newly discovered fish has been named Leporinus villasboasorum, in honor of the pioneering efforts of brothers Orlando, Cláudio and Leonardo Villas-Bôas a half-century ago to protect the Xingu River’s biodiversity and the rights of indigenous peoples there.

Leporinus is the largest and most diverse genus in the characiform family Anostomidae and includes roughly 90 species across most of South America. New species are described yearly and the genus includes many “poorly understood” species complexes, according to Sidlauskas.

“We thought it would be fairly straightforward to look at populations of similar fishes from the Orinoco River basin in Venezuela, the Essequibo River of Guyana, and several of the tributaries of the Amazon River in Brazil and see if they are taxonomically the same or different,” Sidlauskas said. “It turns out that there are at least two new distinct species, and there may be more.”

Both new species are comparatively small – about 8 to 10 inches long – although some members of their family can reach two feet in length. Smaller species are sold as aquarium fish, though in the wild, these omnivores prefer moving water – both for feeding and protection from predators.

The term Leporinus literally means “little hare,” in reference to the large teeth that protrude from the mouth, much like those of a rabbit. The bottom teeth of the two new species are particularly long, and while no one is sure why, the researchers note that it may relate to their foraging on plants, worms and other invertebrates.

It isn’t unusual to discover new fish species, especially in the tropical river basins of South America, the scientists say. The region is vast and the network of rivers and tributaries flows through many different types of terrain and microhabitats, leading to speciation on a fine scale.

To an outsider, the new fish species are not remarkably different from two previously established species, Leporinus desmotes and Leporinus jatuncochi. However, there are significant differences in body shape, coloration, scale counts and genetics, Burns said.

“The differences and divergence between the two new Leporinus species and the established ones may trace back several million years,” Sidlauskas said.

“Preserving these different lineages may be very important because one species may have developed evolutionary traits that the others don’t have,” Burns added.

Sidlauskas said Brazil has recently built the Belo Monte Dam on the Xingu River inside the range of the newly discovered Leporinus villasboasorum. Belo Monte is the fourth-largest dam in the world and has the potential to significantly alter habitats on a huge scale. Such anthropogenic influences can threaten fish species that are geographically distinct and limited in range. The impact of the Belo Monte Dam on the recently named Leporinus villasboasorum has yet to be evaluated.

“There also is a lot of local influence on these major rivers and, in turn, the fish species,” Sidlauskas said.

The study was funded by the National Science Foundation, Fundação Araucária (Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil). Co-author on the study was José Birindelli of Universidade Estadual de Londrina in Brazil. The OSU authors are all affiliated with the Department of Fisheries and Wildlife in the College of Agricultural Sciences. Fish in the study were provided by 28 collections in the United States, South America, Europe and Canada.

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Leporinus enyae

Leporinus enyae

Diatoms have sex after all, and ammonium puts them in the mood

CORVALLIS, Ore. – New research shows a species of diatom, a single-celled algae, thought to be asexual does reproduce sexually, and scientists learned it’s a common compound – ammonium – that puts the ubiquitous organism in the mood.

The findings, published today in PLOS One, may be a key step toward greater understanding of the evolution of sexual behavior and also have important biotechnology implications.

“Our discoveries solve two persistent mysteries that have plagued diatom researchers,” said corresponding author Kimberly Halsey, a microbiologist at Oregon State University. “Yes, they have sex, and yes, we can make them do it.”

Diatoms hold great potential as a bioenergy source and also for biosensing. In addition, their intricate, silica cell walls offer promising nanotechnology applications for materials chemists and drug-delivery researchers.

There are more than 200,000 species of diatoms, and the organisms are abundant nearly everywhere water is found, forming huge blooms in the spring and fall that help drive the marine carbon cycle.

“Diatoms are amazing; their silica frustules are beautiful and exquisite,” Halsey said. “Now that we can control their sexual pathway, that should open the door to being able to make crosses between different diatoms with different characteristics. We should be able to breed them just like we do with corn or rice or strawberries to select for traits that are really desirable.”

Halsey and collaborators in botany and statistics from OSU’s colleges of Science and Agricultural Sciences studied the “centric” Thalassiosira pseudonana species of diatom, a model organism for researchers; it’s one of two diatoms, the other being the “pennate” diatom Phaeodactulum tricornutum, to have had its genome sequenced.

Centric diatoms are radially symmetrical – think of them as shaped like a soup can, Halsey says – and pennate diatoms are bilaterally symmetrical: elongated in the manner of a pea pod.

“Everybody said Thalassiosira pseudonana was asexual, because they’d never seen anything else,” Halsey said. “The general thinking was that it just lost the ability or need to go through sex.”

Other scientists, Halsey notes, had showed T. pseudonana retained genes necessary for meiosis, a type of genetic replication specific to sexual reproduction, and concluded the diatom wasn’t using those genes.

“But we started seeing very different morphologies,” changes in cell structure, Halsey said, in this case related to sexual activity. “We also saw genes expressed that are involved in flagellar structures and assembly, which would only happen with sperm cells.”

Graduate student Eric Moore, lead author on the research, was astonished to learn “these single-celled organisms can differentiate into male and female cells, completely changing their morphologies.”

“In fact, I was convinced my cultures were contaminated before I realized what was actually going on,” he said.

Previous work by other researchers studying different types of centric diatoms showed that growth stress – interruptions of light, changes in salinity, shifts in nutrients – can sometimes, but not reliably, cause cells to become sexual.

“Lab efforts to induce sex in centric diatoms have ranged from sweet talk to torture,” Halsey said.

But manual, microscopic analysis by Halsey’s team found that ammonium, a common compound that’s a metabolic waste product of animals, reliably caused two strains of T. pseudonana and two other centric diatoms to change their cell structures, making eggs and sperm; ammonium caused the diatoms to get ready for sex when at least one other cell growth factor – such as light, phosphorus or silica – was in short supply.

In addition, RNA sequencing showed more than 1,200 diatom genes that changed in activity when ammonium lit the algae’s sexual fires. Halsey suggests that in nature, the protists that graze on the diatom blooms excrete the ammonium that triggers the diatoms’ sexualization.

“The specific collection of environmental factors that make diatoms have sex aren’t yet known,” she said. “But identifying ammonium as a sexuality inducer potentially opens the door to new avenues of research into breeding and genetic modification to control important traits.”

Collaborators also included Brianna Bullington of OSU’s Department of Microbiology, Alexandra Weisberg of the Department of Botany and Plant Pathology, and Yuan Jiang of the Department of Statistics.

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Thalassiosira pseudonana

Northwest researchers map out regional approach to studying food, energy, water nexus

CORVALLIS, Ore. – Natural resource researchers at Oregon State University, Washington State University and the University of Idaho are gearing up for a late-summer summit aimed at addressing food, energy and water challenges as interconnected, regional issues.

The August meeting in Hermiston, Ore. – centrally located to many National Science Foundation-funded research projects – represents the second step of a collaboration that began with an April workshop in Coeur d’Alene, Idaho.

Research offices at the three universities hosted the gathering, where scientists explored ways to partner with each other and with industry to address issues that affect regional economies as well as environmental and human health.

Stephanie Hampton from WSU and Andrew Kliskey from Idaho led the planning of the workshop, at which six teams combined to start five U.S. Department of Agriculture and NSF grant proposals on issues ranging from water conservation to energy infrastructure.

“We’re really building a critical mass of researchers and research experience in the region,” said Chad Higgins, an agricultural engineering professor leading OSU’s role in the partnership. “The workshop was awesome. It exceeded all expectations with mind-blowing scientific discussions, new collaborations formed and new proposals floated. And now we have to keep it going because that was just the opening salvo, not the crescendo.”

Topics for future exploration might be broad – such as, will the region have enough food in 2050? – or narrow, like tracing the impact of a single technology. For example, a more efficient system for irrigation could lead to less energy used for pumping and also result in more food being produced.

“The food, energy, water nexus is so huge that it’s scary, but it’s also exciting,” Higgins said. “There are so many opportunities to look at things either in detail or to try to be broad and think about how the region will be influenced. We can bring each person’s expertise together to predict pain points, like are we going to be scarce in any one resource in the future, and where?”

Janet Nelson, vice president for research and economic development at the University of Idaho, said the tri-state collaboration “will poise us to build relationships among researchers from all three universities with many areas of expertise in order to work toward solutions that improve communities, economies and lives.”

“The University of Idaho is committed to examining issues that are critical not only to the people of Idaho, but also to the entire Northwest region, with rippling effects around the world,” she said.

Those issues include how to best update aging hydropower plants and food production infrastructure.

Cynthia Sagers, vice president for research at Oregon State, notes that when it comes to food, energy and water challenges, a solution in one location can lead to problems hundreds of miles away.

“That’s why this demands regional cooperation,” she said. “I am proud that our three land grant institutions are working together on these issues for a healthy Pacific Northwest." 

Christopher Keane, vice president of research at WSU, echoed the sentiment and said he “looks forward to seeing the results of continued collaboration.”

“Working across disciplines and institutions to ensure a sustainable supply of food, energy and water for future generations is a top research priority for WSU,” he said.

In addition to the August event, the planning team is applying for external funding to support ongoing meetings to help sustain momentum. 

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Sunflowers

Sunflower crop

Engagement with natural environment a significant contributor to life satisfaction

CORVALLIS, Ore. – Looking to improve your overall life satisfaction? Try regularly hiking in a forest or otherwise engaging with the natural environment.

And then, for good measure, look for ways to build your trust in the scientists and policymakers involved in managing the forest where you like to hike.

New research at Oregon State University empirically demonstrates that a variety of mechanisms for engaging nature significantly contribute to a person’s overall well-being.

Chief among those, the study found, was whether people believed their surrounding environments were being managed well – for the earning of income and the underpinning of cultural practices as well as for the pursuit of recreation.

“Whether people feel like things are fair and they have a voice in process of making decisions and whether governance is transparent – those are the foundations of why people even can interact with nature,” said lead author Kelly Biedenweg of OSU’s College of Agricultural Sciences.

Biedenweg, an assistant professor in the Department of Fisheries and Wildlife, and collaborators from Colorado State University and the University of Georgia analyzed results from more than 4,400 respondents to an online survey conducted in the Puget Sound region of Washington state.

The researchers used 13 different metrics to illustrate the relationship between overall life satisfaction and engaging with the natural environment. Among those metrics were community activities, access to wild resources, stress eased by time outdoors, and trust in policymakers.

“Eleven of the 13 had a positive correlation to overall life satisfaction,” said Biedenweg, a social scientist who studies both how humans benefit from the natural environment and the impact human actions have on it. “The links between ecological conditions, like drinking water and air quality, and objective well-being have been studied quite a bit, but the connection between various aspects of engaging the natural environment and overall subjective well-being have rarely been looked at.”

“We wanted to identify the relative importance of diverse, nature-oriented experiences on a person’s overall life satisfaction assessment and statistically prove the relationship between happiness/life satisfaction and engaging with nature in many different ways.”

The researchers quantified the relationship between well-being and six common mechanisms by which nature has effects on well-being: social and cultural events; trust in governance; access to local wild resources; sense of place; outdoor recreation; and psychological benefits from time outdoors.

“Controlling for demographics, all were significantly related to life satisfaction,” Biedenweg said. “The fact that trust in governance was a significant predictor of life satisfaction – in fact, the most statistically significant predictor of the ones we looked at – it was nice to see that come out of the research. The way we manage is the gateway to people being able to get livelihoods and satisfaction from nature.”

Findings were recently published in the Journal of Environmental Psychology. The National Science Foundation and the Environmental Protection Agency supported this research.

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Surf fisherman

New video shows how blue whales employ strategy before feeding

NEWPORT, Ore. – Blue whales didn’t become the largest animals ever to live on Earth by being dainty eaters and new video captured by scientists at Oregon State University shows just how they pick and choose their meals.

There is a reason for their discretion, researchers say. The whales are so massive – sometimes growing to the length of three school buses – that they must carefully balance the energy gained through their food intake with the energetic costs of feeding.

“Modeling studies of blue whales ‘lunge-feeding’ theorize that they will not put energy into feeding on low-reward prey patches,” said Leigh Torres, a principal investigator with the Marine Mammal Institute at Oregon State, who led the expedition studying the blue whales. “Our footage shows this theory in action. We can see the whale making choices, which is really extraordinary because aerial observations of blue whales feeding on krill are rare.”

“The whale bypasses certain krill patches – presumably because the nutritional payoff isn’t sufficient – and targets other krill patches that are more lucrative. We think this is because blue whales are so big, and stopping to lunge-feed and then speeding up again is so energy-intensive, that they try to maximize their effort.”

The video, captured in the Southern Ocean off New Zealand, shows a blue whale cruising toward a large mass of krill – roughly the size of the whale itself. The animal then turns on its side, orients toward the beginning of the krill swarm, and proceeds along its axis through the entire patch, devouring nearly the entire krill mass.

In another vignette, the same whale approaches a smaller mass of krill, which lies more perpendicular to its approach, and blasts through it without feeding.

“We had theorized that blue whales make choices like this and the video makes it clear that they do use such a strategy,” explained Torres, who works out of Oregon State’s Hatfield Marine Science Center in Newport, Oregon. “It certainly appears that the whale determined that amount of krill to be gained, and the effort it would take to consume the meal wasn’t worth the effort of slowing down.

“It would be like me driving a car and braking every 100 yards, then accelerating again. Whales need to be choosy about when to apply the brakes to feed on a patch of krill.”

The researchers analyzed the whale’s lunge-feeding and found that it approached the krill patch at about 6.7 miles per hour. The act of opening its enormous mouth to feed slowed the whale down to 1.1 mph – and getting that big body back up to cruising speed again requires a lot of energy.

The rare footage was possible through the use of small drones. The OSU team is trained to fly them over whales and was able to view blue whales from a unique perspective.

“It’s hard to get good footage from a ship,” Torres said, “and planes or helicopters can be invasive because of their noise. The drone allows us to get new angles on the whales without bothering them.”

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Leigh Torres, 541-867-0895, leigh.torres@oregonstate.edu

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Photo at left: Blue whale feeding on a krill patch.

 

Launching Drone
Launching of the drone.

Flame retardant chemicals may affect social behavior in young children

CORVALLIS, Ore. – Some chemicals added to furniture, electronics and numerous other goods to prevent fires may have unintended developmental consequences for young children, according to a pilot study released today.

Researchers from Oregon State University found a significant relationship between social behaviors among children and their exposure to widely used flame retardants, said Molly Kile, an environmental epidemiologist and associate professor in the College of Public Health and Human Sciences at OSU.

“When we analyzed behavior assessments and exposure levels, we observed that the children who had more exposure to certain types of the flame retardant were more likely to exhibit externalizing behaviors such as aggression, defiance, hyperactivity, inattention and bullying,” said Kile, the corresponding author of the study, which was published today in the journal Environmental Health.

“This is an intriguing finding because no one had previously studied the behavioral effects of organophosphate classes of flame retardants, which have been added to consumer products more recently.”

Flame retardants are found throughout the built environment in furniture, mattresses, carpeting, electronics, vehicles and more. The chemicals are added to the products and are not bound in the material, which causes them to be released into indoor environments.

Manufacturers began adding flame retardants in 1975, in response to new legislation in California designed to reduce flammability in common household items. The state updated its flammability standards in 2014, and now allows furniture manufacturers to meet the standards without adding flame retardant chemicals to their products, but the chemicals are still widely used and they linger in the indoor environment.

There are growing concerns that some flame retardants may have unintended impacts on health and development in children, and this study contributes to that body of research.

The most common types of flame retardants found in the built environment are brominated diphenyl ethers (BDEs) and organophosphate-based flame retardants (OPFRs). OPFRs emerged as an alternative to BDEs in an effort to address some of the environmental health concerns posed by BDEs, which tend to remain in the environment for long periods.

Past research has shown that both BDEs and OPFRs are linked to poorer cognitive function in children. But less is known about the relationship between the flame retardants and children’s social and emotional health, particularly during early childhood, a key developmental period for learning.

“The social skills children learn during preschool set the foundation for their success in school, and also for their social and emotional health and well-being later in life,” said Shannon Lipscomb, an associate professor and lead of the human development and family sciences program at OSU-Cascades and a co-author of the study.

For this study, the OSU research team recruited 92 Oregon children between ages 3-5 to wear a silicone wristband for seven days to measure exposure to flame retardants.

The team included Kile, Lipscomb; Megan McClelland and Megan MacDonald of the OSU College of Public Health and Human Sciences; Kim Anderson of the OSU College of Agricultural Sciences; and Andres Cardenas of the Harvard T.H. Chan School of Public Health and an OSU doctoral graduate. The research was supported by OSU’s Hallie E. Ford Center for Healthy Children and Families and the Environmental Health Science Center at OSU.

The wristbands, developed by Anderson at OSU, have a porous surface that mimics a cell, absorbing chemicals that people are exposed to through their environment. When the wristbands are returned, Anderson can screen for up to 1,200 chemicals that may accumulate. The wristband is an easy and non-invasive way to sample children’s chemical exposure.

The researchers had parents or primary caregivers complete questionnaires about socio-demographics and the home environment, and preschool teachers completed behavior assessments for each participating child. In all, researchers had complete data and wristband results for 69 children.

Their analysis showed that all of the children were exposed to some level of flame retardant. Children who had higher exposure rates of OFPRs showed less responsible behavior and more aggression, defiance, hyperactivity, inattention and bullying behaviors. Children with higher exposure to BDEs were seen as less assertive by their teachers. All of these social skills play an important role in a child’s ability to succeed academically and socially.

“We detected these links between flame retardant and children’s social behaviors while controlling for differences in family demographics, home learning environments and adversity,” Lipscomb said. “This suggests that flame retardants may have a unique effect on development apart from the effects of children’s early social experiences.”

Further study is needed to better understand the links between flame retardants and children’s social skill development, the researchers said. They plan to pursue funding for a new study that continues for a longer period of time and considers how other aspects of children’s lives might affect the impact of flame retardants on their development.

“The results of this research to date have shown potential impacts for child health and warrant a more thorough investigation,” Kile said.

“If scientists find strong evidence that exposure to flame retardants affects children’s behaviors, we can develop strategies that prevent these exposures and help improve children’s lives. This type of public health science is needed to figure out how to address the root causes of behavioral concerns that can affect children’s school readiness and overall well-being.”

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Molly Kile, 541-737-1443, molly.kile@oregonstate.edu; Shannon Lipscomb, 541-322-3137, Shannon.lipscomb@osucascades.edu

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Child wearing a wristband

Keeping Kids Safe

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https://youtu.be/pMvOKVoDA94

 

 

Globe-trotting pollutants raise some cancer risks four times higher than predicted

CORVALLIS, Ore. -- A new way of looking at how pollutants ride through the atmosphere has quadrupled the estimate of global lung cancer risk from a pollutant caused by combustion, to a level that is now double the allowable limit recommended by the World Health Organization.

The findings, published this week in the Proceedings of the National Academy of Sciences Early Edition online, showed that tiny floating particles can grow semi-solid around pollutants, allowing them to last longer and travel much farther than what previous global climate models predicted.

Scientists said the new estimates more closely match actual measurements of the pollutants from more than 300 urban and rural settings.

The study was done by scientists at Oregon State University, the Department of Energy’s Pacific Northwest National Laboratory, or PNNL, and Peking University. The research was primarily supported by PNNL.

"We developed and implemented new modeling approaches based on laboratory measurements to include shielding of toxics by organic aerosols, in a global climate model that resulted in large improvements of model predictions," said PNNL scientist and lead author Manish Shrivastava.

"This work brings together theory, lab experiments and field observations to show how viscous organic aerosols can largely elevate global human exposure to toxic particles, by shielding them from chemical degradation in the atmosphere."

Pollutants from fossil fuel burning, forest fires and biofuel consumption include air-polluting chemicals known as polycyclic aromatic hydrocarbons, or PAHs. In the United States, the Environmental Protection Agency has identified several PAHs as cancer-causing agents.

But PAHs have been difficult to represent in past climate models. Simulations of their degradation process fail to match the amount of PAH that is actually measured in the environment.

To look more closely at how far PAHs can travel while riding shielded on a viscous aerosol, the researchers compared the new model's numbers to PAH concentrations actually measured by Oregon State University scientists at the top of Mount Bachelor in the central Oregon Cascade Range.

“Our team found that the predictions with the new shielded models of PAHs came in at concentrations similar to what we measured on the mountain,” said Staci Simonich, a toxicologist and chemist in the College of Agricultural Sciences and College of Science at OSU, and international expert on the transport of PAHs.

“The level of PAHs we measured on Mount Bachelor was four times higher than previous models had predicted, and there’s evidence the aerosols came all the way from the other side of the Pacific Ocean.”

These tiny airborne particles form clouds, cause precipitation and reduce air quality, yet they are the most poorly understood aspect of the climate system.

A smidge of soot at their core, aerosols are tiny balls of gases, pollutants, and other molecules that coalesce around the core. Many of the molecules that coat the core are what's known as "organics." They arise from living matter such as vegetation -- leaves and branches, for example, or even the molecule responsible for the pine smell that wafts from forests.

Other molecules such as pollutant PAHs also stick to the aerosol. Researchers long thought that PAHs could move freely within the organic coating of an aerosol. This ease of movement allowed the PAH to travel to the surface where ozone -- a common chemical in the atmosphere -- can break it down.

But scientists' understanding of aerosols has changed in the last five years or so.

Recent experiments led by PNNL coauthor Alla Zelenyuk show that, depending on the conditions, the aerosol coatings can actually be quite viscous. If the atmosphere is cool and dry, the coating can become as viscous as tar, trapping PAHs and other chemicals. By preventing their movement, the viscous coating shields the PAHs from degradation.

Researchers developed a new way of representing PAHs in a global climate model, and ran it to simulate PAH concentrations from 2008 to 2010. They examined one of the most carcinogenic PAHs in particular, called BaP. Simulations were compared to data from 69 rural sites and 294 urban sites worldwide, and showed that predictions from shielded PAHs were far more accurate than previous, unshielded ones.

Scientists also analyzed how far the protected PAHs could travel, using both old and new models. In all cases, the shielded PAHs traveled across oceans and continents, whereas in the previous version they barely moved from their country of origin.

To look at the impact globe-trotting PAHs might have on human health, Shrivastava combined a global climate model, running either the shielded PAH scenario or the previous unshielded one, with a lifetime cancer risk assessment model developed by coauthors Huizhong Shen and Shu Tao, both then at Peking University.

Globally, the previous model predicted half a cancer death out of every 100,000 people, which is half the limit outlined by the World Health Organization (WHO) for PAH exposure. But using the new model, which showed that shielded PAHs actually travel great distances, the global risk was four times that, or two cancer deaths per 100,000 people, which exceeds WHO standards.

The WHO standards were not exceeded everywhere. It was higher in China and India and lower in the United States and Western Europe. The extent of shielding was also much lower over the tropics compared to the mid- and high-latitudes. As the aerosols traversed the warm and humid tropics, ozone could get access to the PAHs and oxidize them.

"We don't know what implications more PAH oxidation products over the tropics have for future human or environmental health risk assessments,” said Shrivastava. “We need to better understand how the shielding of PAHs varies with the complexity of aerosol composition, atmospheric chemical aging of aerosols, temperature and relative humidity. I was initially surprised to see so much oxidation over the tropics."

Other supporters of this research included the National Institute of Environmental Health Sciences, the National Science Foundation, the Ministry of Education, Youth and Sports of the Czech Republic, and the Department of Energy Office of Science.

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Staci Simonich, 541-737-9194

staci.simonich@oregonstate.edu

Mary Beckman, 509-375-3688

mary.beckman@pnnl.gov

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Airborne transport

Pollutant transport to regions


Aerosol formation
Aerosol formation and transport

Molecule shows ability to thwart pathogens’ genetic resistance to antibiotic

CORVALLIS, Ore. – Oregon State University researchers have developed a new weapon in the battle against antibiotic-resistant germs - a molecule that neutralizes the bugs’ ability to destroy the antibiotic.

Scientists at OSU were part of an international collaboration that demonstrated the molecule’s ability to inhibit expression of an enzyme that makes bacteria resistant to a wide range of penicillins.

The molecule is a PPMO, short for peptide-conjugated phosphorodiamidate morpholino oligomer. The enzyme it combats is known as New Delhi metallo-beta-lactamase, or NDM-1, and it’s accompanied by additional genes that encode resistance to most if not all antibiotics.

“We’re targeting a resistance mechanism that’s shared by a whole bunch of pathogens,” said Bruce Geller, professor of microbiology in OSU’s College of Science and College of Agricultural Sciences, who’s been researching molecular medicine for more than a decade. “It’s the same gene in different types of bacteria, so you only have to have one PPMO that’s effective for all of them, which is different than other PPMOs that are genus specific.”

The Oregon State study showed that in vitro the new PPMO restored the ability of an antibiotic -- in this case meropenem, an ultra-broad-spectrum drug of the carbapenem class -- to fight three different genera of bacteria that express NDM-1. The research also demonstrated that a combination of the PPMO and meropenem was effective in treating mice infected with a pathogenic strain of E. coli that is NDM-1 positive.

Results of the study, supported by a grant from the National Institutes of Health, were recently published in the Journal of Antimicrobial Chemotherapy.

Geller says the PPMO will likely be ready for testing in humans in about three years.

“We’ve lost the ability to use many of our mainstream antibiotics,” Geller said. “Everything’s resistant to them now. That’s left us to try to develop new drugs to stay one step ahead of the bacteria, but the more we look the more we don’t find anything new. So that’s left us with making modifications to existing antibiotics, but as soon as you make a chemical change, the bugs mutate and now they’re resistant to the new, chemically modified antibiotic.”

That progression, Geller explains, made the carbapenems, the most advanced penicillin-type antibiotic, the last line of defense against bacterial infection.

“The significance of NDM-1 is that it is destroys carbapenems, so doctors have had to pull out an antibiotic, colistin, that hadn’t been used in decades because it’s toxic to the kidneys,” Geller said. “That is literally the last antibiotic that can be used on an NDM-1-expressing organism, and we now have bacteria that are completely resistant to all known antibiotics. But a PPMO can restore susceptibility to antibiotics that have already been approved, so we can get a PPMO approved and then go back and use these antibiotics that had become useless.”

In addition to Geller, the research team included Oregon State postdoctoral scholars Erin Sully and Lixin Li and OSU undergraduate student Christina Moody, as well as scientists from Sarepta Therapeutics, Harvard Medical School, the University of Fribourg, and the University of Texas Southwestern.

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Steve Lundeberg, 541-737-4039

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geller Bruce Geller

Millions of people with metabolic syndrome may need more vitamin E

CORVALLIS, Ore. – New research has shown that people with metabolic syndrome need significantly more vitamin E – which could be a serious public health concern, in light of the millions of people who have this condition that’s often related to obesity.

A study just published in the American Journal of Clinical Nutrition also made it clear that conventional tests to measure vitamin E levels in the blood may have limited accuracy compared to tests made in research laboratories, to the point that conventional tests can actually mask an underlying problem.

Vitamin E – one of the more difficult micronutrients to obtain by dietary means – is an antioxidant important for cell protection. It also affects gene expression, immune function, aids in repair of wounds and the damage of atherosclerosis, is important for vision and neurologic function, and largely prevents fat from going rancid.

Nutrition surveys have estimated that 92 percent of men and 96 percent of women in the United States fail to get an adequate daily intake of vitamin E in their diet. It is found at high levels in almonds, wheat germ, various seeds and oils, and at much lower levels in some vegetables and salad greens, such as spinach and kale.

This study was done by researchers in the Linus Pauling Institute at Oregon State University and the Human Nutrition Program at The Ohio State University, as a double-blind, crossover clinical trial focusing on vitamin E levels in people with metabolic syndrome. It was supported by the National Institutes of Health, the National Dairy Council and DSM Nutrition.

“The research showed that people with metabolic syndrome need about 30-50 percent more vitamin E than those who are generally healthy,” said Maret Traber, a professor in the OSU College of Public Health and Human Sciences, and Ava Helen Pauling Professor in the Linus Pauling Institute.

“In previous work we showed that people with metabolic syndrome had lower bioavailability of vitamin E. Our current work uses a novel approach to measure how much vitamin E the body needs. This study clearly demonstrates that people with metabolic syndrome need a higher intake of this vitamin.”

More than 30 percent of the American public are obese, and more than 25 percent of the adults in the United States meet the criteria for metabolic syndrome, putting them at significantly increased risk for cardiovascular disease and type-2 diabetes – primary causes of death in the developed world.

That syndrome is defined by diagnosis of three or more of several conditions, including abdominal obesity, elevated lipids, high blood pressure, pro-inflammatory state, a pro-thrombotic state and insulin resistance or impaired glucose tolerance.

This research, for the first time, also clearly outlined a flaw with conventional approaches to measuring vitamin E.

By “labeling” vitamin E with deuterium, a stable isotope of hydrogen, scientists were able to measure the amount of the micronutrient that was eliminated by the body, compared to the intake. The advanced research laboratory tests, which are not available to the general public, showed that people with metabolic syndrome retained 30-50 percent more vitamin E than healthy people – showing that they needed it. When the body doesn’t need vitamin E, the excess is excreted.

But in the group with metabolic syndrome, even as their tissues were taking up and retaining the needed vitamin E, their blood levels by conventional measurement appeared about the same as those of a normal, healthy person.

“We’ve discovered that vitamin E levels often look normal in the blood, because this micronutrient is attracted to high cholesterol and fat,” Traber said. “So vitamin E can stay at higher levels in the circulatory system and give the illusion of adequate levels, even as tissues are deficient.

“This basically means that conventional vitamin E blood tests as they are now being done are useless.”

The findings support the conclusion that people with metabolic syndrome have higher levels of oxidative and inflammatory stress, scientists said in their conclusion, and require more antioxidants such as vitamins E as a result.

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Maret Traber, 541-737-7977

maret.traber@oregonstate.edu

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Vitamin E
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Varmint hunters’ ammo selection influences lead exposure in avian scavengers

CORVALLIS, Ore. – Varmint hunters’ choice of ammunition plays a role in the amount of lead that scavengers such as golden eagles could ingest, a new study shows, and offers a way to minimize the lead exposure to wildlife.

Using a new bullet-fragment recovery technique known as “digestion,” the research also suggests that radiographs, or X-rays, a common tool for estimating how much of the toxic metal left is behind in shot pests or game animals, tend to produce low estimates.

A team of researchers that included Oregon State University undergraduate student Mason Wagner and U.S. Geological Survey scientists collected 127 Belding’s ground squirrel carcasses from alfalfa fields in southern Oregon and northern California.

Eleven western states produce roughly 40 percent of the U.S.’s alfalfa, and burrowing mammals such as ground squirrels and prairie dogs can cause significant yield loss. Shooting the rodents is an important form of pest control as well as a popular recreational pastime throughout the West.

The carcasses are typically left on the fields, where avian scavengers like eagles, hawks and kestrels descend upon the carrion to feed both themselves and their nestlings.

This study looked at how much lead remained in the carcasses and how that correlated with the type of bullet used. Models were also created to estimate from radiographs the amount of lead left in a carcass and the potential effect of the lead on nestlings’ mortality, growth and production of an enzyme critical to the blood’s ability to carry oxygen.

Results of the study by Oregon State’s College of Agricultural Sciences and the USGS were recently published in PLOS ONE.

The research found 80 percent of shot carcasses had detectible fragments of lead. The study also found bullet type didn’t have an effect on the number of fragments, but it did influence the mass of the retained fragments. Also, smaller carcasses showed more “pass-through,” i.e. less retained lead.

Squirrels shot with high-velocity, high-mass .17-caliber Super Mag bullets, for example, had 28 times the retained fragment mass of those shot with .22-caliber solid bullets. One percent of the Super Mags’ original mass was left behind, by far the highest percentage of any ammo type, and the Super Mag fragments also dispersed more than two times farther through the carcass – making them more likely to be eaten by a scavenging animal.

Modeling suggested that hawk and eagle nestlings fed regularly with shot ground squirrels could likely lose more than half the production of the key enzyme ALAD throughout the nestling period, though no nestlings would be expected to die of lead poisoning. They could, though, eat enough lead to impair late-nestling-stage growth, but by then they would have done most of their growing anyway.

The digestion procedure for extracting bullet fragments involved processing carcasses into a solution that was run through sieves and a gold-prospecting sluice box. Researchers used digestion on 30 carcasses to determine a relationship between digestion results and radiography results.

“We found that radiographs are not very accurate at estimating how much lead is left in a carcass,” said study co-author Collin Eagles-Smith, a USGS ecologist and OSU courtesy assistant professor of fisheries and wildlife. “They underestimate density when there are more small fragments. Small ones are the pieces that are more digestible and likely to enter the circulatory system.”

Radiography has also been used to estimate how much lead is present in shot game animals such as deer and elk.

In addition to providing a check on the accuracy of estimating via radiography, the research also suggests a way for hunters to minimize the amount of lead left in varmint carcasses.

“The sheer number of carcasses after a hunting session is a challenge to pick up, assuming you can even find all of the carcasses,” said lead author Garth Herring, also a USGS ecologist. “Picking up every last carcass is not realistic, but there are choices people can make regarding ammunition that may result in smaller amounts of lead in the carcasses left behind.”

Eagles-Smith noted that rodenticides, an alternative to shooting, have their own toxicological implications.

“These pests are really an economic threat to farmers, and shooting them is one method to control their numbers,” he said. “Choosing an ammunition type, such as .22-caliber solid bullets, that creates substantially fewer fragments can be a way to minimize lead exposure to scavengers and other wildlife.” 

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Steve Lundeberg, 541-737-4039

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Belding's Ground Squirrel

Belding's ground squirrel