environment and natural resources

Chemical discovered that causes plant tumors

CORVALLIS, Ore. - Researchers in Oregon and elsewhere have discovered a new class of chemicals they call "bruchins" which, even at extraordinarily low levels of exposure, signal a plant to form a benign tumor, apparently as part of the plant's defensive mechanism against an insect pest.

The study, done by scientists from Oregon State University, the U.S. Department of Agriculture and a private company, will be published Tuesday in the Proceedings of the National Academy of Sciences. There is no immediate commercial application that's apparent about this discovery, the researchers said, but the unusual capabilities of this group of chemicals is highly interesting. It's also the first chemical of this type ever identified that can induce tumor formation in plants, they said.

"This is an extremely active new class of chemicals that has a clear impact on plant growth regulation," said William Proebsting, a professor of horticulture at OSU. "We could observe its biological impact on the plant at levels so low we couldn't even physically detect the chemical. Whenever you find a new group of chemicals with this level of activity you get a little excited. And this is also the type of basic discovery that often sets the stage for later applications."

In this research, the scientists studied the interaction of pea plants with pea weevils, a tiny insect that's smaller than a ladybug but is one of the worst insect pests of peas. In order to reproduce, the pea weevil needs to lay its eggs on a pea pod. But the pea plant has apparently developed an innovative and effective response to this insect attack.

When the egg is laid, the pea plant detects in the pea weevil a type of chemical, which the Oregon researchers identified and are calling bruchins (in reference to the scientific classification, bruchid) to which pea weevils belong.

This chemical triggers the pea pod to begin a process of cellular division that actually forms a small tumor, lifting the pea weevil egg up and away from the pea pod. In this position it helps to prevent the emerging weevil larvae from burrowing into the pea pod. It may also fall off, dry out or be eaten by predators, the researchers said, and it reduces the chance that the pea weevil will actually succeed in infesting a pea.

"It's pretty obvious this is a natural defense mechanism that the pea plants have developed, and for purposes of survival in nature, it works pretty well," said Robert Doss, a plant physiologist with the USDA Agricultural Research Service and OSU Department of Horticulture. Doss was a co-principal investigator on the study along with Proebsting and James Oliver, a chemist with the Agricultural Research Service in Beltsville, Md.

All practical applications aside, the scientists said, a chemical such as this is a wonder of nature.

"This may or may not lead to something that is useful in agriculture or elsewhere, but it always helps to understand the relationship between organisms," Doss said. "And anything we find that relates to the control of cell division is pretty important."

The new bruchin chemicals not only are active at extremely low levels, the researchers found, but the reaction of the pea plants to them is highly precise. When artificially applied to pea plants, tumors began to form almost immediately on the pea pods - where they would have a useful role in nature in repelling pea weevils - but there was no effect on most other parts of the same plant.

Earlier researchers had identified a gene in the pea plant that is required for formation of these tumors. Now the Oregon researchers and their collaborators have discovered the key chemical produced by an insect pest that triggers the process.

A number of other plants have similar "galls," or plant tumors on them, the researchers said. The round scabs often found on oak leaves are one example. But this process often actually works to the benefit of the insects that interact with these plants, Doss said, so in various natural systems it's not clear that there is any single evolutionary explanation for the formation of these tumors.

The discovery of basic plant growth mechanisms can have important implications, the scientists said. When a type of plant hormone called "auxin" was first identified years ago that played a role in cell elongation, there was no obvious use for the findings. Later, this basic information led to the creation of root-stimulating hormones, new types of herbicides and other products.

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William Proebsting, 541-737-5454

Volunteers, experts tracking down Oregon plants

CORVALLIS - A grass-roots collaboration of scientists, college students, and everyone from teenagers to senior citizens is working in Oregon to produce something you would think the state has, but it actually doesn't - a modern, complete manual to identify all of the plants in the state.

Called the Oregon Flora Project, the effort is already six years old and may continue for another decade. It's no small task, considering that Oregon has the fourth largest plant species diversity of any state in the nation - 4,430 species, subspecies and varieties known and probably more yet to be discovered. But this information is critical for studying everything from rare plant conservation to the potential effects of climate change or invasions of foreign species, say experts at Oregon State University who are coordinating this project.

"The last manual of this type was produced in 1961 with data mostly from the 1950s and before," said Scott Sundberg, an OSU research assistant professor and coordinator of the project. "Since then probably one-third of the plant names have changed based on extensive botanical research. We really need this information, and almost anyone can contribute if they are willing to volunteer their time."

So far, 230 volunteers around the state have helped in the project, many of them OSU faculty or members of the Native Plant Society of Oregon, a partner and financial supporter of this project. People interested in contributing to the project can do so in many ways, from providing lists of plant species for an area to entering information into databases.

The state has been divided into 174 "blocks" of 576 square miles each, Sundberg said, and volunteers can "adopt" a block to observe and list the plant species found there.

Eventually, the project hopes to produce a checklist that catalogues the plants growing throughout the state; an atlas that maps information about plant distribution on top of such data as precipitation or elevation; and a flora, which is a manual, in both printed and electronic form, for identifying plants.

"These books are as essential as a dictionary for identifying plants," said Linda Hardison, an OSU research associate. "With Oregon's rich and unique habitats, from coastal dunes to mountain and desert, the sheer volume of information can be overwhelming. But this is how people can identify the plants of the state and measure our biodiversity. It's difficult to study anything if you don't know what's out there."

Sundberg says eventually the project may cost $2 million and take up to 15 years. So far, it's been operated on a shoestring budget with free volunteer help, and even small donations are welcome.

It received one substantial boost when Kenton Chambers, professor emeritus at OSU and former director of the OSU Herbarium, started an endowment for the project by selling his 40-year stamp collection for $28,000 and donating the proceeds.

Persons interested in volunteering their help for this project may contact Sundberg at Oregon Flora Project, OSU Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, Ore., 97331-2902, or sundbers@bcc.orst.edu. Tax-deductible donations to support the work can be made by sending checks to Sundberg, made out to the OSU Foundation.

A similar flora project that was done in California took 15 years and yielded a 1,400-page book. The data includes such information as species name, habitat, morphological characteristics, distribution, rarity of the plant, elevation range, horticultural value, and whether the plant is native or exotic.

Scientists involved in this project include taxonomists, biogeographers, computer programmers, statisticians, ecologists, cartographers and geoscientists. Individuals helping out range from professional botanists to high school students and retirees looking for a good excuse to take a nature hike.

Among other things, there is always the chance of discovering a new plant species that no one ever knew existed in Oregon. Large areas of the state have never been adequately explored, Sundberg said, especially some of the remote parts of eastern and southwestern Oregon.

From 1975 to 1994, 58 new species, subspecies or varieties of plants were found in the state - one of the newest is calochortus umpquaensis, or the Umpqua mariposa lily. Or, you can look for plants that may be extinct - Clarkia heterandra, the small-fruited clarkia, hasn't been found in the state since 1888. More information about the Oregon Flora Project can be found at its Web site.

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Scott Sundberg, 541-737-4338

Program to address biotechnology controversies

CORVALLIS - Oregon State University is beginning a new "Program for the Analysis of Biotechnology Issues" that will try to provide impartial and scientifically accurate information to the public about some of the most pressing issues surrounding biotechnology.

Terri Lomax, an OSU professor of botany and plant pathology, has been appointed to a part-time Extension position as the temporary director of this innovative new program, which will be supported by the OSU College of Agricultural Sciences. It will begin immediately.

Combining science and public communication, this will be one of only three university outreach efforts of its type in the nation. It will try to inject scientific accuracy and public education into a field that is increasingly controversial, officials say, and hopefully provide consumers a more balanced option to the often-conflicting viewpoints of private industry or social activists.

"As a public university, we're going to examine the many issues surrounding biotechnology, the real science that is being done, and communicate those findings to the public, whatever they may be," Lomax said. "The citizens, consumers and farmers of America increasingly are asking for a source they can trust for information about biotechnology, and we think OSU has the resources to meet that need."

Lomax said she plans to draw upon a wealth of expertise at OSU in developing the new program, including gene researchers, ecologists, economists, philosophers, and science communicators, in addition to input from an external advisory board. A web site, public speaking engagements, interaction with the news media, and education of county Extension agents are all planned in the new program.

As it evolves, officials in the College of Agricultural Sciences said they eventually hope to expand programs in this area.

"This field is complicated and we need people who can understand both the science and the social concerns," said Mike Burke, associate dean of the OSU College of Agricultural Sciences. "As an accomplished scientist and excellent communicator, we believe Terri Lomax is the ideal person to get this program moving and tap into the other outstanding faculty here at OSU.

"Biotechnology is a field of great social, scientific and economic significance to the world, and OSU is now going to make a serious commitment to improving communication in this area," Burke said. "We think this new program can perform a valuable, even unique service to the public."

As a growing, global industry, the fruits of gene research are now in the commercial marketplace everywhere from the grocery store to the doctor's office. But as this multi-billion dollar revolution in science has evolved, critics have raised many concerns and legitimate questions, Lomax said.

How is this science controlled and regulated? How can researchers make sure there will be no unwanted or uncontrolled transfer of new genetic traits from one organism to another? Are there any human health risks from bioengineered products? Is biotechnology really needed to meet our food, fiber, medical and other needs? What are the alternatives, and what are their relative costs and risks, if society chooses not to use biotechnology?

How is genetic engineering similar to or different from traditional plant breeding techniques? Should the products that have been created with biotechnology be labeled as such in the marketplace? And what are the philosophical or ethical implications of biotechnology?

Sometimes these concerns have been voiced in regulatory hearings or social protests, Lomax said. Other times they have taken the form of violence and vandalism. In Europe, progress in developing or marketing new genetically modified products has ground almost to a halt. In the United States, many companies are reluctant to make a major commitment to the field in light of the uncertainties.

And many consumers, Lomax said, simply aren't sure what to think or whom to believe.

"We'd like to see this program help to answer many of these questions with an approach that people can trust," Lomax said. "At first we'll act primarily as a clearinghouse, helping to find accurate information, interpret it in ways people can understand and pass it along. Later on, we hope to do more original study right here at OSU on both the scientific and social issues."

Lomax is an educator and plant molecular biologist who, in her research work, has used genetic techniques as a tool to understand how plants grow. OSU has many other scientists who work in different aspects of gene research, from crop agriculture to animal science, biomedicine, forestry, pollution control and even the molecular basis of aging. Altogether, about 90 faculty from six colleges work at least partly with biotechnology. The state of Oregon is looking to biotechnology as a major part of its economic growth. And on Wall Street, it's one of the huge growth industries of recent years.

But the new program at OSU will be designed to be neither a proponent of the biotechnology industry, university officials say, nor a forum for unsubstantiated charges. Rather, they say, it will try to identify, interpret and present to the public scientific information on biotechnology as accurately as possible, and let the facts fall where they may.

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Terri Lomax, 541-737-5278

Naturally occurring toxin cause of death in Oregon dog

CORVALLIS, Ore. – A dog that died suddenly after being in the water near Elk Creek in southern Oregon late last month has tested positive for anatoxin-a, a neurotoxin released by naturally occurring blue-green algae, Oregon State University technicians have confirmed.

The dog was tested at OSU’s Veterinary Diagnostic Laboratory, which confirmed the cause of death. At least two other dogs in the same area have died recently under similar circumstances, presumably from the same cause.

“Blue-green algae, or Cyanobacteria, produce toxins that can result in illness and death,” said OSU’s Jerry Heidel, director of the state’s only accredited veterinary diagnostic lab. “A ‘bloom’ or rapid increase in the growth of these algae results in a large number of these organisms in the water. Algae ingested with this water are rapidly broken down in the stomach and potent toxins are released, which can be fatal.”

Heidel said anatoxin-a is a strong neurotoxin that causes almost immediate clinical signs, including muscle tremors, respiratory disease and convulsions. Respiratory paralysis can lead to death within 20 to 30 minutes, he added.

“Once ingested, there isn’t a lot a person can do,” Heidel said. “Diluting the toxins by drinking clean water probably won’t even help. Immediate treatment by a veterinarian is essential, but the prognosis once clinical signs begin is poor. The real key is prevention – and that can be difficult to do.”

Heidel said these naturally occurring neurotoxins also can harm humans, which is why some Oregon lakes have closed in recent years during algal blooms. Livestock also are susceptible to anatoxin-a, and several cows die each year after ingesting stagnant pond water.

Heidel said algal blooms occur in standing, or slow-moving water, during warm temperatures – usually in summer – when there is a good nutrient source to promote growth. Winds can concentrate the algae along shorelines, he added, increasing opportunities for people and animals to contact and ingest the organisms.

“Oregon agencies monitor popular bodies of water frequented by the public for the presence of algae blooms and do a good job of issuing alerts when those waters are potentially dangerous,” Heidel pointed out. “But the public needs to be aware that these potentially fatal blooms can occur in any body of standing or slow-moving water.

“If you take your dog for a walk in the woods, or along a drying creek or lake bed, watch for stagnant, often cloudy water that appears to have algal growth,” he added.

OSU’s Veterinary Diagnostic Laboratory provides the state with a range of animal disease diagnostic services to veterinarians, livestock producers, pet owners, biomedical researchers, and state and federal agencies. More than 16,000 animal tissue and fluid specimens are received annually by the laboratory for diagnostic evaluation. The laboratory also provides a variety of diagnostic procedures, including necropsy, histopathology, virology, bacteriology, clinical pathology, serology and toxicology.

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Jerry Heidel, 541-737-6964

Genome of “potato famine” pathogen sequenced

CORVALLIS, Ore. – A large team of researchers has successfully sequenced the entire genome of one of the most famous pathogens in world history – which caused the Irish potato famine in the 1840s – in work that could ultimately help address a resurgence of this pathogen that is still causing almost $7 billion dollars of agricultural losses annually around the world.

Completion of the project, announced today in the journal Nature, is an important advance that could lead to new avenues of attack on this destructive pathogen, experts say. The work was led by the Broad Institute of Harvard University and MIT, and included collaborators from dozens of other institutions to make a task of this magnitude possible.

“Scientists have studied this pathogen for 150 years and there’s still a great deal we don’t know about it,” said James Carrington, professor and director of the Center for Genome Research and Biocomputing at Oregon State University and collaborator on the project. “It caused one of the most important famines in history and is still a major problem that costs billions of dollars to fight.”

In the short term, Carrington said, studies based on the new genetic “map” may help explain why the pathogen has been so aggressive, virulent and persistent, despite efforts to breed resistance to it. In the long run, the ability to breed far better plants and reduce use of chemicals will benefit from knowing exactly what genetic traits to look for and where they may be found on the huge genome of this pathogen, which has 240 million “base pairs” of DNA.

The pathogen, Phytophthora infestans, is commonly known as “late blight” and can infect potatoes, tomatoes and some other plants. Through its history it has been responsible for many crop epidemics, not the least of which was the Irish potato famine that led to the death of more than one million people in Ireland and a huge wave of immigration to the United States.

“This is probably the most costly plant pathogen, per acre, that we’ve ever had to deal with,” said Nik Grunwald, a plant pathologist with the USDA’s Agricultural Research Service and a courtesy associate professor of plant pathology at OSU. “Part of the problem is that we’ve identified and can grow potatoes with resistance to late blight, but they aren’t the varieties that the marketplace expects.”

The vast majority of potatoes consumed around the world are still russet potatoes that are inexpensive and highly popular, prized for the long, golden french fries they can produce – and extremely vulnerable to this pathogen, Grunwald said. But even with this pathogen to battle, potatoes are an important alternative to cereal crops and the fourth largest food crop in the world.

“We have some potato varieties that are completely resistant to late blight,” Grunwald said, “but most farmers are still growing russets because that’s where the demand is, even if they have to use up to 15 chemical sprays a season to produce them.”

According to Carrington, the genome of P. infestans is unusual, with long stretches of “repetitive DNA” that comprise almost 75 percent of its genome and play some role in its virulence and ability to adapt so rapidly to new environments. Many plants have evolved mechanisms for pathogen resistance, but this pathogen appears to tap into this odd, but massive collage of highly-repeated genome segments to overwhelm those defenses.

“These long sequences of repeating DNA contain virulence determinants, and those provide the ability for Phytophthora to change and adapt so readily to plant defenses,” Carrington said. “We believe it’s the key to the pathogen’s virulence.”

Researchers in Oregon, at both OSU and the USDA, will use their expertise in gene “silencing” – understanding what controls the genes that are activated and what turns them off - as a key part of their effort to decipher the secrets of this pathogen. Other researchers around the nation will continue work to learn about the basic biology and pathology of late blight.

“We’ve made great strides in recent years to do genome sequencing, it’s now becoming almost routine,” Carrington said. “But for these large projects we’re combining the use of powerful computers with teams of chemists, computational scientists, plant pathologists and many other experts to accomplish something that would take a smaller research group a lifetime.”

The researchers said in their report that “P. infestans remains a critical threat to world food security, and the genome sequence is a key tool to understanding its pathogenic success.”

Just this year, an outbreak of late blight has caused unusually early and severe damage to tomato and potato crops in the eastern United States. It’s difficult to control even with applications of fungicides, experts say, and can kill plants faster than almost any other disease.

In the mid-1990s, new and exotic strains of P. infestans made news headlines around the world. Particularly in the U.S. and Canada, the new strains appeared to be as or more pathogenic than any known previous strains, including those that caused the Irish potato famine.

Additional chemical treatments were routinely used and made it clear that, after more than a century, this pathogen has lost none of its virulence. The Oregon researchers believe that the new genome knowledge will accelerate development of chemical-free control methods.

This research was supported by the USDA and the National Science Foundation.

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James Carrington, 541-737-3347

Public interest growing in safety of well water

CORVALLIS - An outpouring of public interest at some recent informational forums about well water suggests there are a lot of Oregonians who are concerned - often with good reason - that their drinking water is not safe, and want to find out what they can do about it.

Several "Well Water Clinics" operated by the Home-A-Syst program at Oregon State University recently concluded in the central Willamette Valley. About 1,000 concerned residents attended those and other sessions. This was "a level of interest that was far more than we had anticipated," said Gail Glick Andrews, an Extension water quality educator with the OSU Department of Bioresource Engineering.

"What this indicates to me is that people are really craving information and want to protect their home water supply," Andrews said. "The odd thing is that many of them thought they were the only ones who didn't know much about this issue. The reality is that many or most people are poorly informed."

One major step that could help address that problem, Andrews said, is new information available on the Internet that will help people learn what they can do to protect their well water supplies. The web address is http://osu.orst.edu/extension/wellwater.

According to Andrews, as many as one-fourth to one-half of the private wells in the state have surface contaminants in them. In some areas, up to three wells out of four may have problems or the users have concerns about nitrate levels.

And with summer approaching, Andrews said, the time is ideal for people to inspect their well systems, have the water tested and make any necessary changes or repairs while the weather cooperates.

"The most basic thing that people don't understand about private water supply is that they personally are the regulator, inspector, maintenance manager, accountant and consumer," Andrews said. "This is not something that's taken care of by some government agency. So if people want clean, safe water to drink from a private well, no one else is going to do anything about it."

The good news, she said, is that there are several support agencies people can look to for information to get started. County Extension offices are the best place to start, she said. They can also obtain information from the new web site, or contact Andrews via e-mail at gail.glick.Andrews@orst.edu.

Andrews said that if properly constructed and maintained, most private wells in Oregon actually produce very safe water. The natural filtering action of soil tends to control bacteria and viruses. Problems are most common with any well-drained soil that speeds the movement downward of surface contaminants, especially in agricultural areas that are heavily fertilized.

Testing for coliform bacteria and nitrate levels every one to three years is recommended, Andrews said, and contrary to common assumptions, taste is not a good indicator of water quality. Some crystal clear water can be contaminated and some foul-tasting water can be fine.

The Extension literature outlines a number of fairly simple things homeowners can do to help protect their well water. They include:

  • Locate your well, septic tank and drain field, as the first step towards managing and protecting these areas.
  • Have your septic tank pumped about every three to five years, depending on household usage patterns.
  • Remove any chemicals stored in your well house, and protect the soils around your property from contamination by oil, gasoline and household chemicals.
  • Make sure there is no water standing around the top of your well.
  • Ensure that a sanitary seal caps your well, to keep out foreign objects and surface contaminants.

Andrews said that the informational and educational programs she works with will continue their efforts around Oregon, and more community educational forums will be planned.

"The main thing people need to keep in mind is that they personally are responsible for making sure their well water is safe, and that they do need to be informed about the issues," Andrews said. "But there is plenty of information available to help, and often some fairly simple changes are all that's needed to correct any problems that are found."

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Gail Andrews, 541-541-737-6294

Cadmium toxicity threatening wildlife in Rocky Mountains

CORVALLIS, Ore. - An alarming number of white-tailed ptarmigan in a large region of the southern Rocky Mountains are suffering from acute cadmium poisoning - an exposure to high concentrations of the extremely toxic trace metal.

Scientists report Thursday in the journal Nature that 46 percent of the adult birds surveyed in a 10,000-square kilometer area in south-central Colorado were found with cadmium accumulations in their kidneys well above the toxic threshold of 100 parts pe r million.

Cadmium toxicity causes kidney and liver dysfunction, brittle bones, and adversely affects reproduction and survival.

Lead author James R. Larison, an Oregon State University professor and alpine ecologist, said the findings are not unlike those that linked the pesticide DDT to a problem of thin-eggshells in the peregrine falcon three decades ago. The implications of th e toxicity go beyond a single species.

"What we found in our study was that a particular genus of plants - willows - were 'biomagnifying' or concentrating cadmium," Larison said. "They act as biological pumps, increasing the concentrations of cadmium by two orders of magnitude. Birds eat a lo t of willow, especially in the winter when other foods are scarce.

"They aren't the only creatures to eat willow, though," he added. "The possibility exists that deer, elk, moose, snowshoe rabbits, beaver and other animals may face similar problems, just as it is possible that other plants - including some vegetables - may have the same abilities to biomagnify cadmium that willow does."

Larison said the human health risk from eating ptarmigan likely is small, unless the internal organs are consumed. But, he added, many people eat vegetables grown in the area and these could pose a risk to human health. The former director of Sea Grant Communications at Oregon State University, Larison has spent the past four years at Cornell University pursuing his doctorate in ecology and evolutionary biology. His doctoral study was funded primarily by the National Ge ographic Society. Other authors in the Nature article include Gene Likens, director of the Institute for Ecosystem Studies in Millbrook, N.Y., John Fitzpatrick, director of the Cornell University Laboratory of Ornithology, and J.G. Crock, a chemist with t he U.S. Geological Survey.

The study focused on an expansive section of Colorado stretching from Denver and Fort Collins to Durango known as an "ore belt." Larison, who has returned to the OSU faculty, said abandoned mines throughout this area have "exacerbated the problem."

Though cadmium is natural to the area, he pointed out, mining tends to mobilize potentially toxic metals. "Cadmium poisoning originally was discovered in Japan, with rice acting as a biomagnifier," Larison said. "Elderly women in particular were affected with severe osteomalacia - a condition not unlike osteoporosis. Trace amounts of cadmium can be found in almost all soils, surface waters and plants, but human activities tend to concentrate it. Mining is one obvious factor, but cadmium also is mobilized by certain industrial and agricultural practices."

Once ingested, cadmium cannot easily be excreted from the body and accumulates, usually in the kidneys and liver. The kidneys are responsible for calcium levels in the blood, Larison said, and when cadmium levels rise and kidneys tubules fail, calcium le vels drop. To compensate, the body "borrows" calcium from bones. In Japan, elderly women eating a diet heavy in cadmium-contaminated rice suffered from severe bone decalcification.

In Larison's study, 57 percent of the adult ptarmigan had damaged kidneys and their bones contained 8 to 10 percent less calcium.

"We also found a number of birds with bone fractures," he said. "For every one we found, there may have been others that did not survive long enough for us to discover them."

Cadmium toxicity in predators eating ptarmigan is a concern, Larison pointed out, because they likely would eat the internal organs and the cadmium would then accumulate in their bodies as well. Ptarmigan predators include eagles and hawks, as well as fo xes and coyotes.

Though the Nature article focuses on one area in the Rocky Mountains, cadmium poisoning potentially could occur elsewhere, Larison said.

"We happened to look at the effects just on white-tailed ptarmigan eating willows in Colorado," Larison said. "But there are some indications that the conditions for cadmium poisoning are widespread."

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Jim Larison, 541-737-8284

Multimedia Downloads

white-tailed ptarmigan

A new study published in Nature found that an alarming number of white-tailed ptarmigan are suffering from acute cadmium poisoning.

ptarmigan fracture

This X-ray image of a ptarmigan shows a fracture caused by calcium deficiency triggered by cadmium-damaged kidneys.

James R. Larison

Jim Larison releases a ptarmigan.

Scientists estimate area of groundwater concern near lab

CORVALLIS - An interagency team of scientists studying fish liver cancer and other fish health problems at an Oregon State University research facility east of Corvallis has estimated an "area of highest potential groundwater concern" around the laboratory.

He estimated area extends north and south of Highway 34, from the Willamette River east approximately two miles to the vicinity of Terra Circle, and southeast along Peoria Road to the old Dixie School.

Although there is not yet direct evidence linking a known groundwater contaminant to the fish problems, persons living within the area of concern should consider drinking bottled water as a precaution, recommended Duncan Gilroy, public health toxicologist with the Oregon Health Division. Use of bottled water outside the area is probably not necessary.

This spring, OSU researchers discovered an unusually high rate of liver cancer and other effects in a number of untreated "control" fish at the Food Toxicology and Nutrition Laboratory, located one mile east of Corvallis on Highway 34. The OSU researcher s previously had experienced a mass fish kill of thousands during December of 1998. Subsequent analysis of the trout's diet, the source and biology of the fish, and laboratory infrastructure and procedures revealed no possible method of contamination, oth er than the source of the lab's water, which is pumped from the groundwater through a series of wells.

Scientists with Oregon Health Division and the Oregon Department of Environmental Quality have been studying the hydrology of the area, and have made some approximations about groundwater movement and the dimensions of the groundwater area providing wate r to the OSU laboratory. A number of private wells also are within this area.

"The area is based largely on groundwater modeling and is only an estimate at this point," emphasized Dennis Nelson, groundwater coordinator for the Health Division's Drinking Water Program. "But it will help identify which households should consider usi ng bottled water."

The area estimated by the agencies is not necessarily an area of groundwater contamination, pointed out Bill Mason, a hydrogeologist with DEQ. Numerous tests of the groundwater thus far have revealed no contaminants that could be responsible for the fish cancer and other effects.

"The task force wants people to understand that the area we have estimated is NOT an area of known groundwater contamination," Mason said. "It is simply an area where private wells could be drawing the same water as the wells at the OSU lab."

Mason said conservative assumptions were used in defining the area of concern, and it is likely that some wells within the area draw water from a different part of the aquifer than the OSU lab. For example, another Oregon State fish laboratory, located l ess than a mile away, has had no apparent problems with its fish.

Scientists with OHD and DEQ have not ruled out the possibility that stream water seeping into the groundwater could carry a contaminant. They therefore also recommend that residents having wells within approximately 100 feet of the East Channel or Muddy Creek consider using bottled water, especially during high water levels in the winter and spring.

Larry Curtis, chair of the Department of Environmental and Molecular Toxicology at OSU, said it is possible that a groundwater contaminant appears only sporadically and could be triggered by high water. The December 1998 incident at the lab that killed t housands of fish occurred during a prolonged rainy period, added Curtis, who chairs the interagency task force.

Curtis said the team is continuing its effort to identify potential contaminants that could have caused the health problems in the fish. The Environmental Protection Agency's national laboratory in Las Vegas is assisting the team in the analysis of addit ional water samples and tissue from the affected fish.

In the meantime, residents who live inside the area of concern should consider using bottled water for drinking and cooking, said OHD's Gilroy.

"Until we know more about what is going on, using bottled water is a sensible precaution," Gilroy said. "We will continue to provide the community with updates as they develop."

A fact sheet with additional details about the fish laboratory and groundwater testing is available by calling the Oregon Health Division at 503-731-4015, or accessing it on the .

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Dennis Nelson, OHD, 541-726-2587

Multimedia Downloads

Oregon Health Division's Drinking Water Program,

This map, produced by the Oregon Health Division's Drinking Water Program, shows an "area of concern" that may be drawing the same well water as an OSU fish laboratory which has experienced high rates of cancer and other symptoms in rainbow trout. (Source: The Oregon Health Division)

Study of huge numbers of genetic mutations point to oxidative stress as underlying cause

CORVALLIS, Ore. – A study that tracked genetic mutations through the human equivalent of about 5,000 years has demonstrated for the first time that oxidative DNA damage is a primary cause of the process of mutation – the fuel for evolution but also a leading cause of aging, cancer and other diseases.

The research, published today in Proceedings of the National Academy of Sciences, also indicated that natural selection is affecting the parts of the genome that don’t contain genes – supposedly “junk” DNA that increasingly appears to have important roles in life processes that are poorly understood.

The analysis was done by scientists at Oregon State University, Indiana University, the University of Florida and University of New Hampshire, in studies supported by the National Institutes of Health.

This research was unusual, scientists say, because the model animal used for the study, a type of roundworm called C. elegans, was tracked through 250 generations and in that period of time accumulated 391 genetic mutations through normal life processes. That’s more than 10 times as many mutations as have ever before been tracked in a study such as this.

Several Nobel Prizes have been awarded based on studies done with this roundworm, which was the first animal to have its entire genome sequenced. And despite their vast evolutionary separation as life forms, this tiny roundworm and humans still share comparable forms of DNA maintenance.

“Genetic mutations in animals are actually pretty rare, they don’t happen very often unless they are induced by something,” said Dee Denver, an assistant professor of zoology at OSU and principal investigator on the study. “The value of using this roundworm is that it reaches reproductive age in about four days, so we can study changes that happen through hundreds of generations, using advanced genome sequencing technology.”

Genetic mutations can take various forms, such as a disruption in the sequence of DNA bases, larger deletions of whole sections of DNA, or other events. They are a fundamental part of the biological process of life and the basis of evolution, allowing organisms to change – sometimes in ways that are good and lead to greater survival value, sometimes bad and leading to decline or death. But the process is difficult to study and a real understanding of the driving forces behind mutation, its frequency, and the types of mutation that happen most often has been elusive, researchers say.

A primary finding of the new study is that a predominant number of genetic mutations – most, but not all of them – are linked to guanine, one of the four basic nucleotides that make up DNA and form the genetic code of life. Guanine is known to be particularly sensitive to oxidative damage.

“Most life on Earth depends in some form on oxygen, which is great at the production of energy,” Denver said. “But we pay a high price for our dependence on oxygen, because the process of using it is not 100 percent efficient, and it can result in free oxygen radicals that can damage proteins, fats and DNA. And this process gets worse with age, as free radicals accumulate and begin to cause disease.”

This is one of the first studies, Denver said, that clearly demonstrates the effects of oxidative damage at a genome-wide scale.

“The research showed that the majority of all DNA mutations bear the signature of oxidative stress,” Denver said. “That’s exactly what you would expect if you believe that oxidative stress is an underlying cause of aging and disease.”

Beyond that, however, the study also found that mutation and natural selection is also operating in the “junk DNA” parts of the roundworm, which actually comprises about 75 percent of its genome but traditionally was not thought to play any major role in life and genetic processes. This suggests that these poorly-understood and little appreciated parts of the genome may have important biological roles that are not yet known, Denver said.

Oxidative stress for decades has been suspected as a mechanism for some of the processes that lead to aging and disease, and it has been studied extensively for that reason. This research provides a better fundamental understanding of the genetic impacts of oxidative stress and its role in both genetic disease and evolution, researchers say.

Story By: 

Dee Denver, 541-737-3698

Wolves in Yellowstone may aid aspen recovery

CORVALLIS, Ore. - A new study suggests that the decline of aspen groves in Yellowstone National Park during much of the past century may be at least partly due to the absence of wolves.

The loss of native aspen groves in Yellowstone and other areas of the Rocky Mountains is reaching crisis proportions, experts say, having declined as much as 50-90 percent in certain areas.

Now, scientists have outlined in more detail the magnitude of the aspen decline in Yellowstone National Park, and developed a new theory for the tree's decline within the park. It links those declines to the loss of wolves, a key predator species, and their interactions with elk and bear populations.

The study was done by Eric Larsen, with the Department of Geosciences at Oregon State University, and William Ripple, professor of forestry and director of the OSU Environmental Remote Sensing Applications Laboratory. It was just published in the journal Biological Conservation.

"This hypothesis is not yet proven, and we're working closely now with National Park Service biologists in more than 115 permanent research plots to test the theory," Larsen said. "What is clear is that the wolves disappeared during the same era that the successful development of mature aspen stands ground to a halt."

The loss of aspen, scientists say, is an ecological crisis that's poorly appreciated by much of the public.

Aspen not only adds scenic beauty to the landscape with their rich golden fall color, but they are often the only significant hardwood present in these conifer-dominated ecosystems. Groves of aspens, which are biologically rich with herbs, shrubs, insects, birds and berries, offer a diversity of plant and animal life often exceeded only in riparian zones in the mountain West.

Using historic documents, aerial photographs, and dendrochronological, or tree ring dating techniques, Ripple and Larsen determined that Yellowstone Park aspen successfully recruited tree-sized aspen into their overstory from about 1751 to 1928, but have been unable to do so since. Various theories have been proposed to explain the lack of aspen overstory recruitment in Yellowstone since the 1920s, including the effects of fire suppression and a trend towards a warmer and drier climate. A key factor on which virtually all scientists agree is that elk browsing has had a major effect on suppressing the growth of young aspen in Yellowstone.

"During winter, elk browse off the aspen suckers, preventing them from growing to a full tree height," Larsen said. "But elk have been in this ecosystem for centuries, so the question becomes why are the aspen declining only now?"

One answer is that due to their protected status, elk populations may now be unusually high. However, there may be additional factors other than just the total number of elk present.

"The difference between the effect of elk on aspen now, compared to periods prior to 1900, may be a reflection of both their population levels and their behavior," Ripple said "Foraging behavior of elk may be influenced by the risk of predation on them."

Wolves are a natural elk predator, the OSU researchers say. Wolf packs not only lower the overall elk population, but may also change elk behavior by their very presence. Elk avoid areas frequented by wolves, which can include aspen thickets, and protect themselves by staying in open areas. By influencing both the total number and foraging behavior of elk, the wolf packs may historically have prevented extensive elk browsing in some of Yellowstone's aspen stands.

Seen as a threat to local herds of elk and bison, the wolves in and near Yellowstone Park were eliminated by 1926. By counting the annual growth rings on a sample of Yellowstone Parks' aspen trees, the OSU research has determined that the 1920s were also the last decade in which aspen overstory trees were able to regenerate.

"When the wolves were eliminated the aspen overstory began to decline, and young trees were unable to join the mature overstory," Larsen said. "Prior to the elimination of the wolf, we documented successful aspen regeneration for a period of at least 170 years."

The ecological link between wolves, elk and aspen is being tested with continued research in Yellowstone Park. The study is comparing aspen growth and survival rates both inside and outside the territories of Yellowstone's wolf packs. The researchers will acquire data on the amount of elk use of those areas and its effect on aspen growth.

This project and others are part of a larger "Aspen Project" at OSU, focusing on the condition of aspen throughout the western United States and Canada. More information can be obtained on the Internet.

"This is one of the most important tree species in these ecosystems," Larsen said. "And in the fall it provides much of the natural beauty in the Yellowstone forests. We have to determine what is happening to these trees and what we can do to prevent their decline."

Story By: 

Bill Ripple, 541-737-3056

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Aspens in Yellowstone National Park

A withering stand of aspen in Yellowstone National Park reflect a phenomenon that researchers from Oregon State University believe is now far more widespread - the loss of wolves in the American West leading to the decline of tree and stream ecosystems.