OREGON STATE UNIVERSITY

college of agricultural sciences

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.

Media Contact: 

Steve Lundeberg, 541-737-4039

Source: 
Multimedia Downloads
Multimedia: 

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.

Story By: 
Source: 

Maret Traber, 541-737-7977

maret.traber@oregonstate.edu

Multimedia Downloads
Multimedia: 

Vitamin E
Vitamin E supplements

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.” 

Media Contact: 

Steve Lundeberg, 541-737-4039

Multimedia Downloads
Multimedia: 

Belding's Ground Squirrel

Belding's ground squirrel

Whale lovers can support Marine Mammal Institute with new license plate

CORVALLIS, Ore. – A new license plate featuring a gray whale and her calf likely will be available to Oregon drivers by summer 2017.

This project is sponsored by the Oregon State University Marine Mammal Institute and enthusiasm for it is running high, said Bruce Mate, director of the institute.

“Everybody I’ve shown the plate design to has loved it,” said Mate, whose institute will receive $35 from the Oregon Department of Transportation every time a vehicle owner spends $40 to buy the plate.

The money will go toward whale research, graduate student education and public outreach.

The license plate depicts the cow-calf pair on a two-tone blue background that emulates sea and sky. In the upper left corner is a lighthouse, and across the bottom it reads “Coastal Playground.”

Renowned wildlife illustrator Pieter Folkens created the lifelike whale images, originally for a poster for the Marine Mammal Institute, which is part of OSU’s College of Agricultural Sciences.

“They’re extremely detailed,” Mate said. “You can see every barnacle.”

The institute paid an application fee of $5,000 to ODOT to begin the license plate process, Mate said, and will pay another $80,000 to cover production costs. In addition, it needs to turn in an “expression of interest” from at least 3,000 vehicle owners stating they plan to buy the plate. Oregon Rep. David Gomberg has helped develop and advance this initiative, which should help promote coastal tourism.

As part of the process to gain public support, 30,000 flyers will be distributed along the coast by Oregon State Parks and Recreation Department volunteers helping out during the annual weeklong “Whale Watching Spoken Here” celebration that runs between Christmas and New Year’s. Each flyer contains an expression-of-interest form.

There will be volunteers at all Oregon coastal headlands to help visitors see southward-migrating gray whales. Between 10,000 and 25,000 whale watchers interact with the volunteers each year during the week between Dec. 25 and Jan. 1, Mate said.

Interest can also be registered online at http://mmi.oregonstate.edu/whaleplate. No financial commitment is required, but it’s asked that only those serious about buying a Coastal Playground plate register.

“It’s a great plate and promotes coastal tourism and just a healthy image for Oregon,” Mate said. “I expect a lot of people will like it, and it’s a way for people to inexpensively support marine mammals.”

It’s not necessary to wait for a vehicle’s registration to need renewal, or buy a new car, to purchase the Coastal Playground plate, Mate noted. For $40, a new plate can be ordered at any time without affecting the vehicle’s registration cycle.

“This plate is a joyful celebration,” Mate said. “Gray whales were on the Endangered Species List because of exploitation, and now they’re the only whale species to have been removed from the list because they’ve recovered. And they’re Oregon’s flagship large whale. Ninety-five percent of the whales you see from shore are gray whales.”

Visible from the coastline year-round, gray whales migrate past Oregon in both directions on their annual journey between Alaska and Baja California. From late April to mid June, northward-migrating females and their calves stay close to shore to avoid predation from killer whales – so close, Mate says, “you could practically skip a stone out to them.”

During the first week in January, the peak time for the southern migration, gray whales pass by Oregon viewing points at an average rate of 35 whales per hour.

Mate said he is banking on the enduring mystique of whales to help the Coastal Playground plate pay off for the Marine Mammal Institute.

“Whales are huge, they’re warm-blooded, they live in an environment we wouldn’t do well in,” Mate said. “They’re really easy to emote with.”

Media Contact: 

Steve Lundeberg, 541-737-4039

Source: 
Multimedia Downloads
Multimedia: 

whale plate

Design of proposed plate

New tag revolutionizes whale research - and makes them partners in science

NEWPORT, Ore. – A sophisticated new type of “tag” on whales that can record data every second for hours, days and weeks at a time provides a view of whale behavior, biology and travels never before possible, scientists from Oregon State University reported today in a new study.

This “Advanced Dive Behavior,” or ADB tag, has allowed researchers to expand their knowledge of whale ecology to areas deep beneath the sea, over thousands of miles of travel, and outline their interaction with the prey they depend upon for food.

It has even turned whales into scientific colleagues to help understand ocean conditions and climate change.

The findings, just published in the journal Ecology and Evolution, showed sperm whales diving all the way to the sea floor, more than 1000 meters deep, and being submerged for up to 75 minutes. It reported baleen whales lunging after their food; provided a basis to better understand whale reactions to undersea noises such as sonar or seismic exploration; and is helping scientists observe how whales react to changes in water temperature.

The ADB tag is a pretty revolutionary breakthrough,” said Bruce Mate, professor and director of OSU’s Marine Mammal Institute in the College of Agricultural Sciences. “This provides us a broad picture of whale behavior and ecology that we’ve never had before.

“This technology has even made whales our partners in acquiring data to better understand ocean conditions and climate change,” Mate said. “It gives us vast amounts of new data about water temperatures through space and time, over large distances and in remote locations. We’re learning more about whales, and the whales are helping us to learn more about our own planet.”

The new tag, the researchers say, expands by several orders of magnitude the observations that can be made of whale feeding and behavior. Researchers say it’s showing what whales do while underwater; when, how and where they feed; how they might be affected by passing ships or other noises; and what types of water temperatures they prefer.

In the new study, researchers outlined the continued evolution and improvements made in the ADB technology from 2007-15, in which it was used on sperm, blue and fin whales. The research has been supported by the Office of Naval Research, the U.S. Navy and the International Association of Oil and Gas Producers.

“By using this technology on three different species, we’ve seen the full range of behavior that is specific to each species,” said Daniel Palacios, a co-author on the study. “Sperm whales, for instance, really like to dive deep, staying down a long time and appearing to forage along the seafloor at times. During summer the baleen whales will feed as much as possible in one area, and then they move on, probably after the prey density gets too low.”

Unlike earlier technology that could not return data from the deep sea for much longer than a day, the new ADB tags are designed to acquire data constantly, for up to seven weeks at a time, before they detach from the whale, float to the surface and are retrieved in the open sea to download data. The retrieval itself is a little tricky – scientists compare it to searching for a hamburger floating in thousands of square miles of open ocean – but it has worked pretty well, thanks to the tags transmitting GPS-quality locations and flashing LED lights once they have released.

The tag can sense water depth, whale movement and body orientation, water temperature and light levels.

“With this system we can acquire much more data at a lower cost, with far less commitment of time by ships and personnel,” said Ladd Irvine, the corresponding author on the study. “This tag type yields amazing results. It’s going to significantly expand what we can accomplish, learning both about whale ecology and the ocean itself.”

Story By: 
Source: 

Bruce Mate, 541-867-0202

bruce.mate@oregonstate.edu

Multimedia Downloads
Multimedia: 

Whale tag

Whale with tag


Whale tag 2

Whale with tag

Whale travels
Whale travel and feeding

OSU Press publishes first guide to Oregon freshwater fishes

CORVALLIS, Ore. – The first comprehensive guide to Oregon’s freshwater fishes has been published by the Oregon State University Press.

Written by Professor Emeritus Douglas Markle in the Department of Fisheries and Wildlife at Oregon State, the guide includes tips on identifying the state’s 137 known species and subspecies, along with photos and illustrations of native and non-native fish.

“A Guide to Freshwater Fishes of Oregon” is available in bookstores, by calling 1-800-621-2736, or by ordering online at osupress.oregonstate.edu

The guide includes information about Oregon’s most iconic fishes – including Chinook and coho salmon – as well as those species not as well-known, such as sculpins and minnows. Markle notes that the number of introduced, non-native fishes continues to increase and “they often are responsible in part for the decline of native fishes.”

“The book is a great guide for anglers and others who may encounter a fish that they cannot easily recognize,” said Marty Brown, marketing coordinator for the OSU Press. “Many groups of Oregon fishes are difficult to identify because of their size, diversity of forms, or lack of study, and there are ongoing debates about the actual number of species and subspecies of fish in the state.”

The guide covers fish both large and small. The white sturgeon is Oregon’s largest freshwater fish, reaching sizes of up to 19 feet and 1,800 pounds, and it is the most long-lived reaching estimated ages of close to 100 years. Among the smaller fish are minnows, which are the largest family of fishes in Oregon, and include such species as the Oregon chub and Umpqua chub – species only found in this state.

Markle is a long-time faculty member at Oregon State who parlayed a childhood interest in aquarium fish into a career teaching and conducting research on deep-sea fishes, coral reef fish, and a variety of freshwater fishes.

In addition to the many color photographs in “A Guide to Freshwater Fishes of Oregon” are numerous illustrations by well-known fish artist Joseph R. Tomelleri.

Story By: 
Source: 

Marty Brown, 541-737-3866, marty.brown@oregonstate.edu;

Doug Markle, 541-737-1970, douglas.markle@oregonstate.edu

Multimedia Downloads
Multimedia: 

Freshwater Fishes of Oregon

Douglas F. Markle

Douglas Markle

Study finds less fragmentation in muzzleloading and black powder cartridge rifles

CORVALLIS, Ore. – A new study found that traditional bullets for muzzleloading rifles and black powder rifle cartridges fragment less upon impact and may leave far fewer lead fragments in game than a modern high-velocity rifle bullet.

The findings suggest that hunters using those styles of guns may have a reduced risk of secondary lead poisoning from consuming game meat, and that there may be a reduced risk to scavenging animals as well, compared to ammunition for modern rifles that also contain lead. 

Results of the study, by researchers in the Department of Fisheries and Wildlife at Oregon State University, have been published in the Journal of Fish and Wildlife Management.

Bullet fragmentation has been well-described in many modern, high-velocity rifles, but not for black-powder cartridge rifles or muzzleloading firearms, said Clinton Epps, a wildlife ecologist at Oregon State and co-author on the study. 

“There is a lot more complexity to the lead versus non-lead ammunition discussion than many people realize and the black powder/muzzleloader niche of hunters needs to be included in the conversation,” Epps said.

To study the fragmentation, the researchers evaluated a traditional .54 caliber round ball and a modern-designed .54 caliber conical bullet for muzzleloaders and two types of .45-70 caliber black powder rifle cartridges, and compared them with a modern, lead-core high-velocity bullet (Remington Core-Lokt) for a .30-06. 

They found that the modern .30-06 bullets retained a mean 57.5 percent of their original mass, with the remaining 42.5 percent fragmenting. Mean mass retention for muzzleloader and black powder cartridge bullets ranged from 87.8 percent to 99.7 percent.

“We tested penetration and fragmentation for each bullet type in both water and ballistics gel,” said Dana Sanchez, an OSU wildlife Extension specialist and lead author on the article. “Obviously, these kinds of artificial tests cannot replicate conditions in the field, but the striking differences in fragmentation suggests follow-up tests on game animals harvested in actual hunting situations may be warranted.” 

Muzzleloaders use black powder, typically made from charcoal, potassium nitrate and sulfur, and loaded from the muzzle using loose components rather than self-contained cartridges. Traditional hunting bullets for muzzleloaders are round balls made of pure lead and wrapped in a cloth patch to engage the rifling. Because of their low velocity and low potential for expansion, most states require muzzleloaders to have larger (greater than .45) calibers than modern high-velocity rifles.

“The speed of a bullet is a key factor in fragmentation, although there are other variables,” said Epps, who is a rifle builder, ballistics specialist and a hunter. “Black powder cartridges and round balls don’t go as fast, so they have to use a bigger bullet, which tends not to break apart as much.” 

Muzzleloader hunting is popular in many states, especially in the Midwest and the South, where special seasons allow hunters to use this method in addition to traditional rifle and archery hunts. Oregon has special muzzleloader tags for deer, elk and pronghorn antelope. Hunting with muzzleloaders and black powder rifles remains a comparatively small niche among hunters and the researchers emphasize that their study was solely intended to provide information on fragmentation that had been missing.

Oregon allows use of both lead and non-lead ammunition in big game hunting. And while non-lead ammunition choices for modern firearms are increasingly more available, Epps said, “non-lead options for muzzleloaders and other older-style firearms are still limited and may not function well in all rifles.” 

David Taylor, a graduate student in OSU’s Department of Integrative Biology, also was an author on the study and conducted the field work as part of an undergraduate project funded in part by the Undergraduate Research, Innovation, Scholarship and Creativity program at Oregon State.

Story By: 
Source: 

Clint Epps, 541-737-2478, Clinton.epps@oregonstate.edu; Dana Sanchez, 541-737-6003, dana.sanchez@oregonstate.edu

Despite evolutionary inexperience, northern sockeye manage heat stress

CORVALLIS, Ore. – Sockeye salmon that evolved in the generally colder waters of the far north still know how to cool off if necessary, an important factor in the species’ potential for dealing with global climate change.

Sockeyes, which spawn in fresh water and spend two to three years in the Pacific Ocean, range from southern Alaska south to the Columbia River.

Research by Oregon State University revealed that sockeyes at the northern edge of that range, despite lacking their southern counterparts’ evolutionary history of dealing with heat stress, nevertheless have an innate ability to “thermoregulate.”

Thermoregulation means that when their surroundings warm up too much, the fish will seek cooler water that precisely meets their physiological needs. A study conducted by an OSU researcher at an Alaska lake during a heat wave shed light on sockeyes’ ability to find the water temperatures they need.

Multiple earlier studies had demonstrated thermoregulation behavior among sockeye salmon at lower latitudes, but northern populations’ behavioral response to heat stress had largely gone unexamined.

While it may seem obvious that any fish would move around to find the water temperature it needed, prior research has shown thermoregulation is far from automatic – even among populations living where heat stress is a regular occurrence.

“Often what’s happened has been counterintuitive, so we had no idea what to expect,” said Jonathan B. Armstrong, assistant professor in the College of Agricultural Sciences’ Department of Fish and Wildlife, the lead author on the study. “About 40 million sockeye return to Bristol Bay every year. These huge salmon runs are a big part of the regional culture and economy, so how these fish respond to climate change will have very real effects on people’s lives. It’s encouraging that the sockeyes showed this innate capacity to respond.”

Results of the research were recently published in Conservation Physiology.

Armstrong and his collaborators at the University of Washington worked in 2013 at Little Togiak Lake – one of five major lakes in the Wood River watershed that drain into Bristol Bay, a fishery that produces nearly 70 percent of all the sockeye salmon caught in the United States. Bristol Bay is close to the 60-degree latitude that marks the northern boundary of the sockeyes’ primary range.

Adult sockeye salmon return to the Wood River system from the Bering Sea in early summer, then mature and develop secondary sexual traits before spawning later in the summer or at the beginning of fall.

During the time between entering fresh water and spawning, the fish group together in their lake’s epilimnion – the upper, warmer level of water in a thermally stratified lake. Usually the fish congregate, or stage, near tributary inlets and along shorelines.

During a staging period of unusually warm weather – maximum daily air temperatures hovered around 80 degrees for a week, the second-warmest heat wave on record – researchers used a seine to capture fish and outfitted 95 of them with devices that logged water temperatures at 20-minute intervals.

What they learned from the 40 recovered temperature loggers was that when the epilimnion temperature rose above about 12 degrees Celsius, or about 53 degrees, the fish thermoregulated by moving to tributary plumes or to deeper water.

By swimming away from the rising temperatures, the fish expended 50 percent less energy during the warmest conditions – 64 to 68 degrees – than they would have had they stayed put.

“The hotter it is, the more energy they burn, but these fish don’t just want the coldest water possible,” Armstrong said. “If they were cars looking for maximum fuel efficiency, they’d just find the coldest water, but instead it’s a Goldilocks sort of thing - they’re looking for not too warm, not too cold.

“They want their system to go fast enough for them to go through maturation before they spawn, where they go from these silver torpedoes to these crazy, exaggerated beasts of sexual selection with a red body and green jaws.”

Armstrong noted the broader message of the study is what it says about the ability of animals to exploit the kinds of diversity of temperature and diversity of habitat found in ecosystems that are intact and not heavily developed.

“There’s all this diversity and connectivity up there,” Armstrong said. “Fish have lots of options for coping with warming or environmental change in general.

“When we develop watersheds, we often simplify habitats and take away these options. In our research we are constantly stumbling across new and interesting ways that fish and wildlife thrive by exploiting diversity in temperatures, often at small spatial scales that would be very easy to overlook. This study is one more example of how all the little details matter, and they could be what save animals from climate change, or at least reduce the impacts.”

Media Contact: 

Steve Lundeberg, 541-737-4039 

Multimedia Downloads
Multimedia: 

sockeye salmon

Sockeye salmon

The golden drool: Study finds treasure trove of info in saliva of foraging bears

CORVALLIS, Ore. – The rivers and streams of Alaska are littered in the summer and fall with carcasses of tens of thousands of salmon that not only provide a smorgasbord for hungry brown bears but are also the newest database in the arsenal of wildlife biologists.

A new study, published this week in the journal PLOS ONE, documents the ability of researchers to gather DNA from residual saliva on partially consumed salmon to the point that they can even identify individual bears from the genetic samples. The discovery should provide a significant boost to research on the population and health of brown bears, which can grow to a size of 1,500 pounds. 

“In the past, population estimates have been largely based on visual observations and on the analysis of fecal samples,” said Taal Levi, an assistant professor of fisheries and wildlife at Oregon State University and co-author on the study. “We found that using bear saliva is not only easier and cheaper as a research tool, it is more effective.”

In their study, the researchers examined 156 partially consumed salmon carcasses of lakeshore-spawning sockeye salmon in the Chilkoot watershed and stream-spawning chum salmon at Herman Creek in the Klehini watershed – both near Haines, Alaska. They also swabbed a total of 272 brown bear “scats,” or fecal samples, from those same locations. 

They found that the saliva collected from the salmon carcasses delivered a higher rate of genotyping success, allowing the researchers to identify individual bears more accurately and quickly than the fecal samples, and required significantly less labor.

“Bears love salmon because they are such a rich food source, and fortunately for us, the way they consume them lends itself to genetic monitoring,” said the study’s lead author, Rachel Wheat, who conducted the research as part of her doctoral dissertation at the University of California, Santa Cruz. 

“When salmon are plentiful, bears rarely eat the entire fish. In some cases, they only eat the brain, and we’ve found that swabbing along the edges of the braincase gives us the best results for extracting DNA,” Wheat said. “We also had success with swabbing inside distinct bite holes, and in the muscle tissue where the bears have stripped the skin off the salmon.”

The researchers were able to get brown bear genotypes for 55 percent of all the salmon carcasses sampled for saliva, compared to 34 percent for the scat samples. 

From a purely cost-savings perspective, the saliva sampling proved cheaper. It costs the researchers roughly $370 per bear to genetically identify individual animals using scat samples; the cost with saliva samples dropped to $118.

“This advance will help allow us to more effectively – and more economically – study one of the largest bears on the planet,” Wheat said. 

Levi agreed and also noted that the method does not have to be restricted to bear research. It could be adapted to other species, as well.

 “Many predators leave saliva on food remains,” he said. “We feel this type of saliva sampling could become an important tool for wildlife population monitoring.”

Story By: 
Source: 

Taal Levi, 541-737-4067, taal.levi@oregonstate.edu; Rachel Wheat, 719-439-3397, r.e.wheat@gmail.com

Multimedia Downloads
Multimedia: 

Bear with salmon (Photo by Jennifer Allen)

Bear with salmon

Chum salmon (Photo by Rachel Wheat)

Chum salmon

Fall Creek hatchery to hold annual festival on Nov. 5

CORVALLIS, Ore. – The Oregon Hatchery Research Center will host its annual Fall Creek Festival on Saturday, Nov. 5, from 10 a.m. to 4 p.m. at the hatchery, located 13 miles west of Alsea on Highway 34.

The festival, which is free and open to the public, features a day of art workshops – scheduled for 10:30 a.m. and 2 p.m. – as well as children’s activities and tours. Registration is required because space is limited; lunch will be provided for registered participants.

To register, call 541-487-5512 and state workshop preferences, or send an email to oregonhatchery.researchcenter@state.or.us

“It’s a wonderful opportunity to see wild coho and Chinook salmon spawning in Fall Creek,” said David Noakes, an OSU professor of fisheries and wildlife.

The workshops include:

  • Water color painting
  • Fish printing
  • Bird house construction
  • Grocery bag stenciling
  • Wind chime construction
  • Nature journal illustration

The center is jointly operated by the Oregon Department of Fish and Wildlife and Oregon State University’s Department of Fisheries and Wildlife.

Story By: 
Source: 

David Noakes, 541-737-1953, david.noakes@oregonstate.edu

Multimedia Downloads
Multimedia: