In nature, apparently, bigger is not always better.
Researchers at Oregon State University and Diversa Corporation have discovered that the smallest known free-living cell also has the smallest genome, or genetic structure, of any independent cell. Yet this tiny organism dominates life in the oceans, thrives where most other cells would die, and plays a huge role in the cycling of carbon on Earth.
“The ocean is a very competitive environment, and these bacteria, known as SAR11, apparently won the race,” said Stephen Giovannoni, an OSU professor of microbiology. “Our analysis of the SAR11 genome indicates that they became the dominant life form in the oceans largely by being the simplest.”
Giovannoni’s team has found that SAR11 has one of the most compact, streamlined genomes ever discovered.
“This organism is extremely small and efficient, with almost no wasted DNA,” Giovannoni said. “Every genetic part serves a purpose, more so than any other genome we’ve studied.”
“By comparison, humans are mostly junk DNA, with large parts of the human genome having no important function,” Giovannoni said.
This type of genome streamlining, researchers say, appears to be a major factor in the evolutionary success of SAR11, which they believe may have been thriving for a billion years or more. One scientific hypothesis holds that natural selection acts to reduce genome size because of the metabolic burden of replicating “junk” DNA with no adaptive value. SAR11 supports that theory.
SAR11 was first discovered by Giovannoni’s team in 1990. Researchers are particularly interested in the microbe because of the critical role it plays in the earth’s carbon cycle, according to Giovannoni. SAR11 is a major consumer of the organic carbon in the oceans, which nearly equals the amount of carbon dioxide in the atmosphere.
“SAR11, through its sheer abundance, plays a major role in the Earth’s carbon cycle,” Giovannoni said. “Quite simply, this is something we need to know more about.”
Collaborators on the new study included the University of Hawaii and Diversa Corporation of San Diego. Funding was provided by the National Science Foundation, Diversa Corporation, the Gordon and Betty Moore Foundation, and the OSU Center for Gene Research and Biotechnology.
Get To Know Oregon Trees
Did you know that lodgepole pine was first named by Lewis and Clark? Or that there are more than 1,000 varieties of pears but only a half-dozen are grown commercially?
The new expanded edition of Trees to Know in Oregon offers an entertaining mix of identification and anecdote with maps and color photographs to help readers get to know Oregon trees.
Edward C. Jensen, an OSU forestry professor, is the primary author and principal photographer of the new edition of the book. But Jensen is quick to recognize the contributions of others, especially the book’s original author, retired OSU Extension forestry specialist Charles R. Ross, who modeled the first edition after books he loved as a child.
Comprehensive and thoroughly readable, Trees to Know in Oregon is far more than a field guide, with updated sections on ornamental trees, Oregon’s forests, and record-breaking big trees.
According to the book, Oregon is home to more than 50 national champion trees listed in the American Forestry Association’s National Register of Big Trees. For example, Oregon has the nation’s largest black cottonwood (320 inches around), black walnut (278 inches around), and garden plum (a 47-foot giant more than 10 feet around).
Learn more about Oregon trees. The book costs $12 per copy and is available from many county offices of the OSU Extension Service. Or, order by calling 1-800-561-6719.
Is suburban life making people overweight? Or could it be that overweight people tend to choose the suburban life?
In a study recently published in the Journal of Regional Science, researchers from Oregon State University found that the relationship between obesity and urban sprawl may be a two-way street.
Economists Andrew Plantinga from OSU’s Department of Agricultural and Resource Economics and Stephanie Bernell from OSU’s Department of Public Health found that the relationship between obesity and urban sprawl may be due to personal preferences when choosing a home location rather than to direct impacts of the suburban environment on physical activity and weight.
Location, location, location.
Plantinga and Bernell found that the relationship between obesity and urban sprawl can be explained by the way people sort themselves by personal preference. Their study suggests that an individual’s body weight may be a factor determining the desirability of a residential location.
In a follow-up study, Plantinga and Bernell used a national data set to test whether body mass index influences the decisions of adults to locate in counties with a high or low degree of sprawl. To measure body weight, the researchers used data from the U.S. Department of Labor’s National Longitudinal Survey of Youth, which has tracked statistics on thousands of individuals since their youth in 1979. The researchers examined many factors, among them ethnicity, gender, age, income, education, marital status, and body weight.
“Among people who moved recently, we find that in addition to a high body mass index, being female, younger, and married increases the probability of choosing to reside in a sprawling county,” Bernell said.
“In many sprawling areas, distances are too great for people to walk to work or to the store,” Plantinga explained. “Transportation infrastructure is often designed for automobiles, with the result that walking and bicycling are impractical and unsafe. The incentives are for people to drive instead of walk. In contrast, in urban neighborhoods like the Pearl District in Portland, people can walk to work, school, or shopping. In many cases, it’s easier to walk to the store than to drive.”
Previous studies had suggested that the relationship between obesity and urban sprawl is related to suburban environments that discourage routine physical activity such as walking and biking. However, previous studies did not consider the choices people make in selecting where to live.
“When you select a residential location, you are really choosing a bundle of attributes,” Plantinga said. “The house you choose may be near a shopping center or a park, or it may have a three-car garage and a bonus room. The market sets a price on each of these attributes. It follows that individuals, given their income, will choose locations that provide the attributes of greatest value to them. People who value walking will tend to choose walkable neighborhoods. People who do not care for walking will tend not to.”
These findings have implications for urban planners and public health officials, according to Plantinga. Many recent planning initiatives include funding for bicycle and pedestrian facilities in order to increase physical activity. However, making communities more exercise-friendly may simply attract people who are predisposed to physical activity.
Plantinga and Bernell’s study, “The Association Between Urban Sprawl and Obesity: Is it a Two-way Street?” is available online:
Can You Hear Me Now?
Songbirds with cell phones? Researchers at Oregon State University have hatched a plan to chart the migration routes of songbirds by equipping the tiny flyers with miniaturized cell phones.
Funded by a three-year, $750,000 grant from the National Science Foundation, the OSU research team plans to build a series of stripped-down, miniature cell phones that would register the birds’ presence as they pass by cell towers in populated areas during their long migrations.
“If we are successful, the same technology could be used to track a variety of migratory animals, not just songbirds,” said W. Douglas Robinson, an avian ecologist in OSU’s Department of Fisheries and Wildlife.
About half of the world’s 9,200 bird species are songbirds, including jays, robins, chickadees, warblers, and sparrows — the “birds you see around your neighborhood,” said Robinson. Although tiny in size, many songbirds are marathon flyers, migrating between North and South America every spring and fall.
The number of some kinds of songbirds is declining. Much of that decline is attributed to habitat loss, but other factors may be involved.
“We can’t address management issues until we know what these songbirds do and where they go,” Robinson said. So he came up with the idea of using cell phone technology to track the birds.
Robinson enlisted Huaping Liu of OSU’s College of Engineering, a former systems engineer for code-division multiple-access mobile cellular systems at Lucent Technologies.
“It is a very, very challenging problem,” Liu said. “The first step is to strip down all of the functions that are unnecessary. The birds don’t talk. They don’t need games and voice mail. What is important is that when the phone powers on, it sends a signal to the cell tower that identifies which bird it is. And then we need to work with the cell companies to identify the tower locations.”
In addition, the weight of the phones cannot exceed 5 percent of the birds’ body weight. That means the phones can weigh no more than two dimes.
“We think the way to lighten the phone is to implement a digital clock,” Liu said. “We’ll use migration estimates and when they think birds may arrive in an area, a coded timer will turn on to connect with cell towers.”
Current battery capacities will allow them to try connecting to the towers about 20 times during a three-week period, which would give them a very high probability of connecting, Liu said.
If they are successful, there might be other applications for the technology.
“The military is interested in the results, and so is the medical community,” Robinson said. “With cardiac patients, for example, you could monitor heart rhythms and, if a troubling pattern emerges, the ‘cell phone’ could send a signal directly to a physician for diagnosis.”
Can you hear me now?
Oregon’s tsunami warning signs go global
The illustration shows a big wave and a figure running up a steep hill. The message is clear: when a tsunami is about to hit the coast, head for high ground.
The illustration, created by Oregon State University Extension Service designer Tom Weeks, has been displayed on the Oregon coast for many years as part of the state’s tsunami warning system.
Now Weeks’s illustration is being used to warn coastal residents around the world, providing unmistakable instructions in the universal language of pictures.
The tsunami warning illustration is one in a series of communication graphics Weeks developed as part of OSU’s efforts to help people move quickly to safety in the event of an earthquake or tsunami. Other illustrations graphically identify tsunami hazard zones, evacuation routes, and assembly areas. The signs have been adopted in other Pacific coastal states -— Washington, California, Alaska, and Hawaii — as part of the National Tsunami Hazard Mitigation Program, a collaborative state-federal program to improve tsunami warning systems and public awareness.
Jim Good, an OSU Extension Sea Grant scientist, developed the tsunami sign concepts with state geologists and planners and worked with Weeks on the illustration designs.
Following the Indian Ocean tsunami last winter, Good’s graduate student, Somrudee Meprasert, went to Thailand to serve on a tsunami assessment group, and she took copies of the signs with her to share with Thai officials. In May, Weeks’s illustration was posted on new warning signs along Thai beaches as part of Thailand’s new National Disaster Warning Centre.
“Extension Sea Grant’s leadership and Tom’s clear, unambiguous design will now save lives around the world, not just in the United States,” Good said.
The year of the vole
This year’s wet spring let loose a flood of unexpected proportions. It was a flood of little rodents called voles, which chewed their way through the Willamette Valley’s grass seed crop this summer, then moved into vineyards and orchards in the fall.
Gray-tailed voles gobbled up as much as 80 million pounds of grass seed this year, according to Mark Mellbye, field crops specialist for the Oregon State University Extension Service in Linn, Lane, and Benton counties. Annual ryegrass, a staple of Oregon’s grass seed crop, was hit especially hard, with as much as a 40 percent crop loss.
“This is the worst vole outbreak on record for the south Willamette Valley and caused the worst damage to our seed crops that anyone can remember,” Mellbye said. The U.S. Department of Agriculture declared nine Oregon counties agriculture disaster areas because of weather and vole damage.
And now voles are moving into vineyards and orchards, chewing bark and girdling young trees and vines, according to Ross Penhallegon, horticulture agent for the OSU Extension Service in Lane County.
In response, the OSU Extension Service is coordinating a Vole Task Force, with Oregon Department of Agriculture officials and the grass seed industry, to survey the extent of crop yield damage and help growers stem the tide of voles.
Often referred to as meadow mice or field mice, voles breed rapidly. A female can produce a new litter of 4 to 8 young every three weeks and breed again immediately after delivering young. Typically, their populations peak every 3 to 5 years, according to Dan Edge, head of OSU’s Department of Fisheries and Wildlife.
While the flood of voles has been difficult for growers, it has been easy pickings for hawks, owls, herons, and other animals that prey on the rodents. “Voles are little packages of protein to these predators,” Edge said.
DVD helps land managers plan for the future
Rural land managers reflect on their past and plan for the future in a new DVD, “Landmarks in Conservation,” produced by the Oregon State University Extension Service.
“The DVD draws on the experiences of nearly 30 land managers from across Oregon,” said Bill Braunworth, agriculture program leader for the OSU Extension Service. “It demonstrates the importance of resource management planning, whether you operate a five-acre farm near Portland or a 100,000-acre ranch in southeast Oregon.”
The DVD holds nearly two hours of video clips, and its companion website serves as a gateway to more than 120 print, video, and online resources to give land managers access to research-based information in an understandable, user-friendly fashion.
“The insights and stories of these Oregon land managers are really what bring this project to life,” Braunworth said.
“They help viewers understand the connection between healthy natural resources and a profitable, sustainable operation.”
“Landmarks in Conservation” (DVD-1) is a cooperative effort by the OSU Extension Service, the USDA Natural Resources Conservation Service, and the OSU Foundation. To order a copy ($19.95 plus shipping), call toll-free, 1-800-561-6719.